Synthesis and Structures of Transition Metal Complexes

Derived from a Pentafluorophenyl Substituted

2-Pyridyl Amido Ligand

LAI, Yin Man

A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of

Master of Philosophy in

Chemistry

November 2008

AN 0

Thesis/ Assessment Committee

Professor Kin Shing Chan (Chair)

Professor Hung Kay Lee (Thesis Supervisor)

Professor Hak Fun Chow (Committee Member)

Professor Raymond Wai Yeung Wong (External Examiner)

Acknowledgement

I would like to take this opportunity to express my sincere thanks to my

supervisor, Prof. Hung Kay Lee, for his guidance and advices during my research

study. I would also like to thank Prof. Thomas Mak, Prof. Chi Keung Lam, Prof.

Raymond Wong and Miss Bella Chan for the X-ray structural studies. Thanks

also go to Dr. Yu San Cheung, Dr. Kendrew Mak and Mr. Man Ho Lee for their

assistance in measuring magnetic moments and ^ F NMR spectroscopy of some of

the metal complexes. My appreciation also goes to my labmates for their help

throughout my study.

Most importantly, support from my beloved family and my friends, makes

me strong to counter difficulties during my research study.

Lastly, financial support from The Chinese University of Hong Kong is

gratefully acknowledged.

Yin Man Lai

Department of Chemistry

The Chinese University of Hong Kong

September, 2008

Abstract

Over the past decades, amido ligands have been widely investigated due to

their flexibility in ligand designs. Considerable efforts have been devoted to the

development of amido ligands with sterically demanding substituents. However,

studies of electronic properties of amido ligands have received relatively less

attention. Our research work has been focused on the chemistry of transition

metal complexes derived from the highly electron-withdrawing

pentafluorophenyl substituted 2-pyridyl amido ligand

[N(C6F5)(2-C5H3N-6-Me)]- (LC6F5).

Chap te r 1 gives an overview on amidometal chemistry. The preparations

of the ligand precursor [HN(C6F5)(2-C5H3N-6-Me)] (HLC6F5) (1) and the

potassium salts of the LC6F5 ligand [K(LC6F5)(tmeda)]2 (2) and [K(LC6F5)(thf)2]2 (3)

are also discussed.

Chap te r 2 deals with the synthesis of Group 4 -6 metal complexes of the

LC6F5 ligand. The tris(amido) complexes [Zr(LC6F5)3(Cl).(C7H8)] (4) and

[Cr(LC6F5)3] (6) were synthesized and structurally characterized. The V(III)

derivative V(LC6F5)3 (5) was also prepared. The result of elemental analysis is

consistent with the empirical formula of complex 5.

Chap te r 3 reports the coordination chemistry of the LC6F5 ligand towards the

later transition metals (Mn—Ni). Metathetical reaction of the potassium amide 2

with one equivalent of anhydrous MCI2 (M = Mn, Fe, Co, Ni) yielded the

corresponding metal(II) diamides of the type [M(LC6F5)2(tmeda)] (M = Mn 7’ Fe 8，

II

Co 9, Ni 10). X-Ray crystallography revealed that complexes 7-10 are

mononuclear and isostructural. Reaction of 1:2 2/FeCl2 yielded the monoamido

complex [Fe(LC6F5)(Cl)(tmeda)] (11). Subsequent reaction of 11 with LiNH2,

LiMe and potassium metal only led to the bis(amido) complex [Fe(LC6F5)2(tmeda)]

(8). Besides, the reaction of FeCl3 with the potassium amide 2 yielded the Fe(III)

tris(amido) complex Fe(LC6F5)3 (12).

Chapter 4 summarizes the results of our work. III

摘要

過去數十年，氨基類配體在結構設計上的靈活多樣性受到了化學家

的廣泛關注。以往的硏究主要是關於配體位阻效應，而對電子效應的硏究相

對較少。本論文報導我們對[N(C6F5)(2-C5H3N-6-Me)r (L^^''')的配位化學

的硏究。

第一章簡要介紹了氨基類配體及其金屬絡合物的合成和特性。包括配體

前體[HN(C6F5)(2-C5H3N-6-Me)] (HL^' ' ' )⑴及鉀驢[K(L^' ' ' ) ( tmeda)]2 (2)

和[K(LC6F5)(thf)2]2 (3)的合成 °

第二章描述了第四至第六組前過渡金屬配合物的合成。配合物

[Zr(L^^^^)3(Cl).(C7H8)]⑷和[Cr(Le6F5)3] (6)被成功分離和表徵。配合物

V(Le6F5)3 (5)則通過元素分析得到表徵。

第三章是關於後過渡金屬的配位元化學。兩當量2和一當量的無水MCh

(M = Mn, Fe, Co, Ni)反應生成[M(LC6F5)2(tmeda)] (M = Mn 7，Fe 8, Co 9, Ni

10)�SS合物的磁矩和相應的電子構型一致°通過反應I:2 2/FeCl2，得到二價

鐵的配合物[Fe(L"'')(Cl)(tmeda)] (11) °我們進一步硏究了配合物11的反應

活性。配合物11與氨基鋰、甲基鋰和金屬鉀反應，只能產生配合物8。另

外，三當量的2和FeCb反應生成了配合物Fe(Le6P5)3(i2)。

第四章總結了本硏究之工作結果。

IV

Abbreviations

Groups or Functions Ad adamantyl Ar aryl Bu" n-h\xiy\

Bu' 紐-butyl Cp cyclopentadienyl Cy cyclohexyl Et ethyl Me methyl Ph phenyl Pr' i^c^propyl Py pyridyl R alkyl

NMR Spectroscopy 5 chemical shift br broad signal d doublet dd double of doublet dt double of triplet J coupling constant m multiplet s singlet t triplet

Miscellaneous Anal. analysis ave. average Calc. calculated dec decomposed M.p. melting point r.t. room temperature

V

Compound 2 [K(L^^^^)(tmeda)]2

Compound 3 [K(L^''')(thf)2]

�N火 N'CeFs

thf>

thr

\ \

K K / thf

�thf

Y I

P.9

Compound 4 邮閒)3((：1) • CyHg] cL

-ft

Compound 5 p.35

VI

List of Compounds

[HN(C6F5)(2—C5H3N—6-M Compound 1 e)]orHLC6F5 力 N 八

I

P.8

p.9

^ 6F5

A

C

—

/

N >

i

K

N

I :N \

: N Z I

CeFs

z 卜

r ^ N ^ V x

/ R：

I ^ N ,F \ I )=N F

VII

5

3

d-

p.54

p.54

p.54

p.54

Compound 6 [0(严5 )3 ]

Compound 7 [Mn(L^^^^)2(tmeda)]

Compound 8 [Fe(L^^^^)2(tmeda)]

Compound 9 [Co(L^^^^)2(tmeda)]

Compound 10 [Ni(L^^^^)2(tmeda)]

> N�

J F

N'

:N /

N Z

t

F F / ' X

Compound 11 [Fe(LC6F5)(ci)(tmeda)]

Compound 12

VIII

P.6

p.69

CI

N «

Fi

F

—N I

Table of Contents

ACKNOWLEDGEMENT I

A B S T R A C T II

臓 IV

A B B R E V I A T I O N S V

LIST OF COMPOUNDS VI

TABLE OF CONTENTS DC

C H A P T E R 1 A 2 - P Y R I D Y L A M I D O L I G A N D C O N T A I N I N G A

P E N T A F L U O R O P H E N Y L S U B S T I T U E N T 1

1.1 GENERAL BACKGROUND 1

1 .2 EXAMPLES OF AMIDO LIGANDS 3

1 .3 AN OVERVIEW ON AMIDO LIGANDS CONTAINING ELECTRON-WITHDRAWING

SUBSTITUENTS 5

1 .4 OBJECTIVES OF THIS WORK 7

1.5 RESULTS AND DISCUSSION 8

1.5.1 PREPARATION OF HL^^^^ (1) AND ITS POTASSIUM DERIVATIVES 8

1.5.2 PHYSICAL CHARACTERIZATION OF COMPOUNDS 1-3 ]0

1.5.3 MOLECULAR STRUCTURES OF COMPOUNDS 2 AND 3 13

1.6 EXPERIMENTALS FOR CHAPTER 1 19

1 .7 REFERENCES FOR CHAPTER 1 2 2

CHAPTER 2 ZIRCONIUM(IV), VANADIUM(ni) AND CHROMIUM(ni)

COMPLEXES DERIVED FROM THE [N(C6Fs)(2-CsH3N"6"ME)l LIGAND 27

2 .1 AN OVERVIEW ON Z R ( I V ) , V ( I I I ) AND CR(III ) COMPLEXES SUPPORTED BY

2-PYRIDYL AMIDO LIGANDS 27

2 . 2 RECENT RESULTS FROM OUR GROUP 3 2

2 . 3 OBJECTIVES OF THIS WORK 33

2 . 4 SYNTHESIS AND STRUCTURES OF TRIS(AMIDO) COMPLEXES OF Z R ( I V ) , V ( N I ) AND

CR(III ) 34

2.4.1 SYNTHESIS OF [2略腦)3((：1> • CYHS] (4), V ( L 園 ) � � ANDLCROF'� 1 (6)……“34

2.4.2 MOLECULAR STRUCTURES OF FZRLL^'^^^ICO'CYHSJ (4), AND (6) 37

2 . 5 EXPERIMENTALS FOR CHAPTER 2 4 3

IX

2 .6 REFERENCES FOR CHAPTER 2 45

C H A P T E R 3 M A N G A N E S E ( I I ) , I R O N ( I I ) , C O B A L T ( I I ) A N D N I C K E L ( I I )

C O M P L E X E S O F T H E � N ( C 6 F S ) ( 2 - C S H 3 N " 6 ~ M E ) ] - L I G A N D 4 9

3 .1 A BRIEF REVIEW ON AMIDES OF THE LATE TRANSITION METALS 4 9

3 . 2 EXAMPLES OF LATE TRANSITION METAL COMPLEXES SUPPORTED BY 2-PYRIDYL

AMIDO LIGANDS 51

3 . 3 OBJECTIVES OF OUR STUDIES 53

3 . 4 SYNTHESIS AND STRUCTURES OF BIS(AMIDO) COMPLEXES OF MN(II ) , FE(II) , CO(II)

AND NI(II) 54

3.4.1 SYNTHESIS OF [M(LF^^^)2(TMEDA)][M = MN (7), FE (8), CO (9), NI (10)] 54

3.4.2 MOLECULAR STRUCTURES OF COMPLEXES 7-10 5 7

3 . 5 SYNTHESIS, STRUCTURE AND REACTIVITY OF A MONO(AMIDO) FE(II) COMPLEX... 61

3.5.1 SYNTHESIS OF[FE(L^)(CO(TMED(OJ (11) 61

3.5.2 PHYSICAL CHARACTERIZATION OF COMPOUND 11 62

3.5.3 MOLECULAR STRUCTURES OF COMPOUND 11 62

3.5.4 REACTIVITY STUDIES OF�FE(LC6’(CL>(TMEDA)�(11) 66

3 .6 SYNTHESIS OF FE(III) TRI(AMIDO) COMPLEX 6 9

3 .7 EXPERIMENTALS FOR CHAPTER 3 7 0

3 .8 REFERENCES FOR CHAPTER 3 73

C H A P T E R 4 S U M M A R Y O F T H E P R E S E N T R E S E A R C H W O R K 75

T A B L E O F A P P E N D I X 79

GENERAL PROCEDURES, PHYSICAL MEASUREMENTS AND X - R A Y STRUCTURAL ANALYSIS. 8 0

I H N M R O F H 严 ‘ ⑴ 82

" C N M R O F H L C , 1 ) 83

I9FNMROFHLC®"S (1) 8 4

IH N M R O F IK(L"^S)(TMEDA)�2 (2) 85

" C N M R OF [ K ( L C ® " S ) _ D A ) ] 2 (2)) 86

I9F N M R O F [K(L"^S)(TMEDA)12 (2)) 87

IH N M R OF [K(LC®•勺(THF)2H (3) 8 8

" C N M R OF [K(LC证勺(THF)2�2 (3) 8 9

� N M R OF�K(LC研S)(THF)2�2 (3) 9 0

IH N M R O F Z R ( L , ( C L ) . ( C 7 H 8 ) 1 (4) 91

SELECTED CRYSTALLOGRAPHIC DATA OF COMPLEXES 2 AND 3 9 4

SELECTED CRYSTALLOGRAPHIC DATA OF COMPLEXES 4 AND 6 95

SELECTED CRYSTALLOGRAPHIC DATA OF COMPLEXES 7 AND 8 96

X

SELECTED CRYSTALLOGRAPHIC DATA OF COMPLEXES 9 AND 10 97

SELECTED CRYSTALLOGRAPHIC DATA OF COMPLEX 11 9 8

XI

CHAPTER 1 A 2-Pyridyl Amido Ligand

Containing a Pentafluorophenyl Substituent

1.1 General Bacl^round

Metal amides refer to those compounds with one or more amido ligand(s)

[NRR,r (R, R' = H, alkyl, aryl or silyl) attached to the metal center. The typical

structure of a metal amide is depicted in Chart 1-1.^

M——N

R

R, Chart 1-1

Over the past decades, considerable efforts have been directed towards the

development of various ligand systems as alternatives to cyclopentadienyl ligands

(Chart 1-2).2 Studies of amido ligands have attracted much attention because of

their flexibility in ligand design via double substitution on the amido nitrogen

atom. By incorporating substituents of different steric and electronic properties,

the reactivity of the corresponding metal complexes can be modified.

R R, N

M M

Cyclopentadienyl ligand Amido ligand

Chart 1-2

/

M

Alkoxy ligand

In 1856, Frankland synthesized the first metal amide, Zn(NEt2)2. This zinc

amide was prepared by the reaction of diethyl zinc with diethylamine (Equation

ZnEt2 + 2 HNEt2 Zn(NEt2)2 + 2 C2H6

Equation 1-1

The development of amidometal chemistry was pioneered by the research

groups of Burger, Wannagat, Bradley and Lappert in 1960s and 1970s/'^' “

Early work in the field was initiated by an exploration on the reactivity of

metal-nitrogen bonds. In the past decades, the chemistry of transition metal

amides has attracted much research interest because of their importance in various

industrial and biological processes. Examples of industrial processes include

amination of alkenes and preparations of heterocycles such as pyridine/"^ which

involve catalytic reactions of amines as synthetic reagents. In biological studies,

metal amido species are believed to be intermediate species that occur in

enzymatic reactions such as those involve in nitrogenase.^

with an amido pendant functionality an amido nitrogen bridged Ref. lOe between two phosphine coligands

Ref. lOf

Chart 1-3

1.2 Examples of Amido Ligands

Chart 1-3 shows a number of metal complexes supported by amido ligands

with different steric and electronic properties.

(Me3Si)2N——Ni: � � � � P P h 3

'PPh3

Me2N\

monodentate, monoanionic Ref. 10a

tridentate, trianionic Ref. 10b

V Fe

/ \ �s旧 iA/ |e2

N

w a

N N

r

/

0

bidentate, monoanionic Ref. 10c

diamido, dianionic Ref. lOd

H

2

9 i

/妒

P

P

The chemistry of 2-pyridyl amido ligands is one of the research focuses in

our group. This type of monoanionic ligands has been extensively studied by

several research groups lOd, 11-13 Some examples are illustrated in Chart 1-4.

R 入 广

R = H, Me R’ = H,Ad，SiMe3，

SiBu^e. or SiBu中h:

e

R=SiMe3, Bu'

Chart 1-4

f 1 r y

e ^

Ar = 2,6-C6H3Me2, 2,4,6-C6H2Pr'3

2-Pyridyl amido ligands belong to an interesting class of amido ligands due

to their flexibility in their binding modes (Chart 1-5). lod They are capable of

stabilizing a number of main-groups and transition metal complexes/^ as well as

lanthanide complexes^^ with different coordination geometries and different

degree of association.

Z R 'N N

I M

monodentate TV-centered

M

bidentate A/,A -chelating

Chart 1-5

I I M——M'

MA -bridging

1.3 An overview on Amido Ligands Containing

Electron-withdrawing Substituents

The reactivity of amidometal complexes depends on both steric and

electronic properties of substituents attached to the amido nitrogen atom. Earlier

studies were focused on the use of amido ligands containing bulky substituents.

A number of sterically demanding amido ligands are illustrated in Chart 1-4. On

the other hand, studies on the electronic properties of amido ligands have received

relatively less attention. In recent years, the incorporation of the highly

electron-withdrawing fluorine substituents to amido ligands has attracted an

increasing interest. These ligands have proven to stabilize main groupi^c’ i ’

transition m e t a l a n d lanthanide species^^ with unusual molecular

geometries. A few examples of fluorinated amido ligands are depicted in Chart

1-6.

M = Re R = Br M = Ti R = py

Ref. 19c

F

N

\ 一 Br

�

F

M = Fe, Co Ref. 20

I -CCFC Nd•……,nZ �

C 6 F 5 � , / \ \

)6F5 Cerg CrfI r j \�6汗5

61-5

Ref. 17

F E t o N ^ S b — R

R = N(C2H5)2, N(C6F5)(2-C5H4N) Ref. 14c

Ar ^ ^ N � � � � � 0 E t 2

� 0 E t 2

Ar=2,6-C6H3'Pr2 Ref. 15

Ref. 17

Chart 1-6

Ar F

M = Zr, Hf Ar= 2，6-C6H3'Pr2 R = CI, Me, 'Bu, CHzPh

Ref. 15

M = Fe L = thf M = Co L = py

Ref. 18

1,4 Objectives of This Work

Over the past decades, the chemistry of metal amides has attracted much

research interest. 2-Pyridyl amido ligands belong to a class of versatile ligands,

which form complexes with a number of metal ions. Previous works reported in

the literature were focused on the use of amido ligands with sterically demanding

substituents. In this research project, the coordination chemistry of the highly

electron-withdrawing pentafluorophenyl substituted 2-pyridyl amido ligand

[N(C6F5)(2—C5H3N-6-Me)]—(lC6F5) was examined.

A N 八

(HLC6F5)

1.5 Results and Discussion

1.5.1 Preparation of HL ^ ^ (1) and its Potassium Derivatives

The new compound [HN(C6F5)(2-C5H3N—6-Me)] (HLC6F5，” " a s

synthesized according to a procedure similar to that reported for

[HN(C6F5)(C6H5)].21

F

I 丄 1) UBu", tmeda, thf, r.t., 2h 丄 11 丄 I

八 z NH2 " " " 2 ) LiNHs.CeFe, thf. reflux, 8h N N ^ ^ ^ ^ F

F

1 70%

Scheme 1-1

Lithation of 2-amino-6-picoline with LiBu" (1.6 M in hexane) in the

presence of the tmeda, followed by treatment with lithium amide and

hexafluorobenzene under reflux gave a dark brown solution. The mixture was

extracted with diethyl ether and the crude product was developed by column

chromatography to give compound 1 as a white solid in 70% yield (Scheme 1-1).

The compound was recrystallized from hexane.

Attempted lithiation of 1 in diethyl ether with one equivalent of LiBu" in the

presence of one equivalent of tmeda gave only an intractable oil (Scheme 1-2).

Schrock and co-workers have also reported an unsuccessful preparation of lithium

salts of fluoro-substituted ligands.i^

广 N 入

LiBu", tmeda, EtzO

r.t. ,4h intractable oil

Scheme 1-2

Although attempts to prepare the lithium salt of the ligand were

unsuccessful, its potassium derivatives (2 and 3) were readily prepared by

treatment of 1 with potassium hydride as illustrated in Scheme 1-3.

A

力 N 八

H I

KH, tmeda, toluene

r.t.. 4h

KH. thf

r.t, 4h

Scheme 1-：

CeFs \ I

u 2 80%

thf \

thf

N N X K K

/

N�yN

,thf

�thf

6F5 X j

20%

In the presence of one equivalent of tmeda, treatment of 1 with one

equivalent of potassium hydride in toluene gave compound 2 as yellow crystals in

80% yield.

On the other hand, treatment of a solution of 1 in thf, in the absence of tmeda,

with one equivalent of potassium hydride gave compound 3 as pale yellow

crystals in 20% yield. The low product yield of compound 3 may be attributed

to a high solubility of the compound in the polar thf solvent, which renders the

isolation process difficult. Both complexes 2 and 3 are sensitive towards

moisture and oxygen.

1.5.2 Physical Characterization of Compounds 1-3

Compounds 1-3 have been characterized by ^H, ^ C and ^ F NMR

spectroscopy, elemental analysis, as well as melting-point determination. The

solid-state structures of compounds 2 and 3 were determined by single-crystal

X-ray crystallography. Table 1-1 lists some physical properties of these

compounds.

Table 1-1 Some physical properties of compounds 1一:

Compound Yield (%) Colour M.p. C O

70

80

20

white solids

yellow crystals

pale yellow crystals

113-114

200-203

214-215 (dec)

The ipi, 13c and ^ F NMR spectral data of compounds 1-3 are summarized in

Table 1-2. The ^H NMR spectra of the compounds show a singlet resonance

signal at 2.0-2.4 ppm, which is assignable to the 6-Me substituent of the L 閉

ligand. The pyridyl protons show three sets of signals at 5.9-7.5 ppm. The

tmeda ligand of compound 2 elicits two singlet signals at 1.87 and 1.99 ppm.

10

The ^H NMR spectrum of compound 3 shows the presence of only one thf

ligand molecule, as revealed by peak integration at 5 1.40 and 3.54, whilst two thf

molecules are observed in the crystal structure of the compound (See section

1.5.3). This is attributed to the loss of one thf ligand molecule under vacuum

during the preparation of the NMR sample.

The 13c NMR spectra of 1-3 are normal. Only one set of resonance signals

due to the ligand were observed. The resonance signals due to the carbon

atoms of the CeFs ring have a lower intensity, probably due to a fast relaxation

rate of these carbon atoms.

The I9F NMR spectra

-80 - -112 ppm, which are

and para-positions.

of compounds 1-3 show three

assignable to the fluorine atoms

resonance signals at

at the ortho-, meta-

11

Tabl

e ^H

, 13c

and

^F

NM

R S

pect

ral D

ata

(ppm

) for

Com

poun

ds 1

-

Com

poun

d Ce

Fe

CH3

NH

C5

H3N

tm

eda/

thf

^H N

MR

(30

0.13

MH

z)

1

13�

NM

R (75

.47

MH

z)

1

i9F N

MR

(37

6.30

MH

z)

1 3

136.

5 (m

), 14

1.3

(m),

135.

2 (m

), 14

1.5

(m),

137.

4 (m

), 14

1.4

(m).

139.

9 (m

), 14

4.5

(m)

140.

9 (m

), 14

4.6

(m)

140.

7 (m

), 14

4.5

(m)

-80.

4 (d

), -9

4.2

�,

-99.

6 (t)

-9

1.0(

d),-

103.

5 (t)

, -1

11.4

(s)

-90.

4 (s

),-1

03.0

(t),

-1

10.2

(s)

2.39

(s)

6.

05 (

br)

2.16

(S)

-

2.06

(S)

-

24.1

-

24.5

--

24.3

--

6.33

(d)

, 6.6

9 (d

), 7.

43 (

t)

6.03

(dt

), 6.

11(d

), 7.

04 (

dd)

5.97

(dt

), 6.

10(d

), 7.

05 (

dd)

105.

0, 1

15.8

, 13

8.5,

154

.3,

157.

5

105.3, 107.5, 137.8，

156.2, 165.0

105.

2, 1

07.8

, 13

8.1,

156

.4,

164.

8

1.87

(s),

1.99

(s)

1.40

(m),

3.54

(m

)

45.1

, 57.

5

25.8

, 67.

8

*Sol

vent

for

com

poun

d 1

is CD

CI3,

whi

le s

olve

nt f

or c

ompo

und

2 an

d 3

is C

eDe.

12

1.5.3 Molecular Structures of Compounds 2 and 3

1. Molecular Structure of [K{N(C6F5)(2-C5H3N-6-Me)}(tmeda)h (2)

The solid-state structure of compound 2 with the atom-numbering scheme is

shown in Figure 1-1. Selected bond distances (A) and angles (。）are listed in

Table 1-3. Compound 2 crystallizes in a monoclinic crystal system with the

space group CUc. X-Ray crystallography revealed that compound 2 is dimeric

with the amido nitrogen atoms N1 and NIA bridging two potassium ions. In

addition, each potassium ion is also bound by a chelating tmeda molecule.

The average K-Npyridyi bond distance in 2 is 2.887(3) A, which is shorter than

the average K - N a m i d o bond distances of 2.955 A. As N1 is bridging between K1

and KIA, the bond distances of K(l)-N(l) and K(1)-N(1A) are expected to be

longer as compared to the K-Npyridyi distances. The K(1)—K(1A) distance in

complex 2 is 3.689(1) A.

Both the K - N a m i d o and K-Npyridyi bond distances in 2 are shorter than that of

2.955 A (average) and 2.931 A (average), respectively, in the closely related

[K{N(SiBu'Me2)(2-C5H3N-6-Me)}(tmeda)]2 complex?� The N(l)-K(l)-N(2)

bite angle in 2 is 46.28(9)。，which is slightly larger than that of 45.2 ( 1 ) � i n

[K{N(SiBu'Me2)(2-C5H3N-6-Me)}(tmeda)]2.22

13

Figu

re 1

-1

Mol

ecul

ar s

truc

ture

of

[K{N

(C6F

5)(2

-C5H

3N—

6~M

e)}(

tined

a)]2

(2)

Ther

mal

elli

psoi

ds a

re p

lotte

d at

30%

pro

babi

lity

leve

l.

Table 1-3 Selected bond distances (A) and angles (。）for compound 2

K(l)-N(l) K � - N �

K(l)-N �

N � - C ( l ) N(1)-C(7)

2.903(3) 2.887(3) 2.919(4) 1.360(5) 1.365(5)

K(1)-N(1A) K � - N ( 3 ) K(1)—K(1A) N(2)—C �

2.915(3) 3.028(4) 3.689(1) 1.345(5)

N(l)-K(l)-N(2) N(1)-K(1)-N(1A) K � - N � - C �

N(l)-C(l)-N(2)

46.28(9) 101.30(7) 97.1(2) 114.5(3)

N(3)-K(l)-N(4) N(1)-K(1)-N(1A) K(l)-N(l)-C(l) C(l)-N(l)-C(7)

61.2(1)

101.30(7) 96.0(2) 119.3(3)

15

2. Molecular Structure of [K{N(C6F5)(2-C5H3N-6-Me)}(thJ)2]2 (3)

The molecular structure of compound 3 with the atom-numbering scheme is

shown in Figure 1-2. Selected bond distances (A) and angles (。）are listed in

Table 1-3. The dimeric compound 3 crystallizes in a monoclinic crystal system

with the space group P2\/n. The two ligands bridge between two

potassium metal centers through both the amido and pyridyl nitrogens.

The K-Namido bond distances K(l)-N(l) and K(1)-N(1A) in 3 are 2.802(3) A

and 2.901(3) A (average 2.852 A), respectively. They are shorter than that of

2.955 A (average) in [K{N(SiBu'Me2)(2-C5H3N-6-Me)}(tmeda)]2.22 The

K -Npyr idy i bond distances K(l)-N(2) and K(1)-N(2A) in 3 are 2.973(3) A and

3.136(3) A (average 3.055 A). They are longer than that of 2.787 A (average) in

[K{N(SiBu'Me2)(2-C5H3N-6-Me)}(tmeda)]2^^ where both the amido and pyridyl

nitrogens in the latter complex bridge between two potassium centers.

The N ( l ) - K ( l ) — N � angle in 3 is 44.5(1)�. For the thf ligand molecules,

the K(l ) -0(1) and K(l) -0(2) distances are 2.758(4) and 2.749(4) A, respectively,

whilst the 0 ( l ) -K( l ) -0 (2 ) angle is 87.6(1)�.

16

Figu

re 1

-2

Mol

ecul

ar s

truc

ture

of

[K{N

(C6F

5)(2

—C

5H3N

-6~M

e)}(

thf)2

]2 (

3)

Ther

mal

elli

psoi

ds a

re p

lotte

d at

30%

pro

babi

lity

leve

l.

Table 1-4 Selected bond distances (A) and angles (") for compound 3

K(l)-N(l) K(1)-N(2) K � - O �

K(1)—K(1A) N � - C �

K(1)-N(1)-K(1A) K(1)-N(2)-K(1A) N(l)-K(l)-N(2) N(l)-C � - N �

O � - K � - O �

2.802(3) 3.136(3) 2.758(4) 3.568(1) 1.353(5)

77.44(8) 71.42(7) 44.5(1) 113.7(4) 87.6(1)

K(1)-N(1A) K(1)-N(2A) K � - 0 ( 2 ) N � - C �

N � - C ( 7 )

N(1)-K(1)-N(1A) N(2)-K(1)-N(2A) K � - N ( 2 ) - C �

K � - N � - C �

C(l)-N(l)-C(7)

2.901(3) 2.973(3) 2.749(4) 1.356(5) 1.376(5)

102.56(8) 108.58(7) 85.9(2) 100.4(3) 121.4(3)

18

1.6 Experimentals for Chapter 1

Materials:

2-Amino-6-picoline, w-butyllithium (ca. 1.6 M in hexane), and LiNH: were

purchased from Acros. Hexafluorobenzene was purchased from Alfa Asear.

All of these reagents were used as received.

A^’A/;A/"',A^'-Tetramethylethylenediamine (Acros) was distilled over sodium and

degassed by freeze—thaw cycles twice before use. Potassium hydride (Aldrich)

was washed with hexane to remove the paraffin oil before use.

Synthesis of Compounds:

[HN(C6F5)(2-C5H3N-6-Me)] (HLC6F5，i). To a mixture of 2-amino-6-picoline

(6.5 g, 60 mmol) and tmeda (9 ml, 60 mmol) in thf (80 ml) was added dropwise a

solution of «-butyllithium in hexane (45 ml, 1.6 M, 72 mmol). The reaction

mixture was stirred at room temperature for 2h, and then added to a mixture of

LiNH2 (1.5 g, 65 mmol) and CeFg (7.6 ml, 66 mmol) in thf (30 ml). The

resultant mixture was refluxed under nitrogen for 8h. All the volatiles were

removed in vacuo and the residue was extracted with diethyl ether. The crude

product was purified by column chromatography using hexane/ethyl acetate (10:1)

as eluent (Rf 二 0.31). Removal of the solvent gave compound 1 as a white solid,

which was recrystallized from hexane. Yield: 11.5 g, 70%. M.p: 113-114

1h N M R (300.13 MHz, CDCI3): 5 2.39 (s, 3 H, Me), 6.05 (br, 1 H, NH), 6.33 (d, J

==8.1 Hz, 1 H, C5H3N), 6.69 (d, J = 7 . 5 Hz, 1 H, C5H3N), 7.43 (t,J= 7.8 Hz, 1 H,

C5H3N). 13c NMR (75.47 MHz, CDCI3): 5 24.1 (Me), 105.0’ 115.8, 138.5,

154.3, 157.5 (C5H3N), 136.5 (m), 139.9 (m), 141.3 (m), 144.5 (m) (CeFs). ^'F

NMR (376.30 MHz, CDCI3)： 5 -80.4 (d, J = 19.9 Hz, ortho-F), -94.2 (t, J =21.4

19

Hz, para-V\ -99.6 (t, J = 20.7 Hz, meta-V). Anal. Found: C, 52.69; H, 2.54; N,

10.12 %. Calc. for C12H7N2F5： C, 52.57; H, 2.57; N, 10.21 %.

[K(LC6F5)(tmeda)�2(2). To a slurry of potassium hydride (0.8 g, 20 mmol) and

tmeda (2.6 mL, 17 mmol) in toluene (20 mL) was added dropwise a pale yellow

solution of HLC6F5 (4.70 g, 17 mmol) in toluene (20 mL) at 0。(：• The pale

yellow reaction mixture was stirred at room temperature for 4h and filtered. The

filtrate was concentrated to ca, 20mL to yield compound 2 as yellow crystals.

The product was washed three times with toluene and dried in vacuo. Yield: 6.9

g, 80 0/0. M.p: 200-203 ^H NMR (300.13 MHz, CeDe): 5 1.87 (s, 24H,

NMei), 1.99 (s, 8 H, NCH2), 2.16 (s, 6 H, Me), 6.03 (dt, J = 8.4, 2.7 Hz, 2 H,

C5H3N), 6.11 (d,J= 6.9 Hz, 2 H, C5H3N), 7.04 (dd, J= 8.4, 6.9 Hz, 2 H, C5H3N).

13c NMR (75.47 MHz, CsDs): 5 24.5 (Me), 45.1 (NMe!), 57.5 (NCH2), 105.3,

107.5, 137.8, 156.2, 165.0 (C5H3N), 135.2 (m), 140.9 (m), 141.5 (m), 144.6 (m)

(C6F5). i9F NMR (376.30 MHz, CgDs): 5 -91.0 (d, J = 18.4 Hz, ortho-F), -103.5

(t, 20.7 Hz, meta-F), -111.4 (s,para-Fy Anal. Found: C, 50.37; H, 5.22; N,

13.09 0/0. Calc. for C36H44N8F10K2： C, 50.46; H, 5.17; N, 13.07 %.

20

[K(LC6F5)(thf)2�2 (3). To a slurry of potassium hydride (0.8 g, 20 mmol) in thf

(20 mL) was added dropwise a pale yellow solution of HL^^"^ (4.7 g, 17 mmol) in

thf (20 mL) at 0 The reaction mixture was stirred at room temperature for 4h

and filtered. The filtrate was concentrated to ca. 10 mL to yield compound 3 as

pale yellow crystals. The product was washed with thf and dried in vacuo.

Yield: 1.5 g, 20 %. M.p: 214-215�C (dec). ^H NMR (300.13 MHz, CgDe): 5

1.40 (m, 8 H, thf), 2.06 (s, 6 H, Me), 3.54 (m, 8 H, thf), 5.97 (dt, J = 8.4, 2.4 Hz, 2

H , C5H3N), 6 .10 (d, J = 7.2 Hz , 2 H, C5H3N), 7 .05 (dd, J = 8.4, 7 .2 Hz , 2 H ,

C5H3N). " c NMR (75.47 MHz, CgDg): 5 24.3 (Me), 25.8 (CH2), 67.8 (OCH2),

105.2, 107.8, 138.1, 156.4, 164.8 (C5H3N), 137.4 (m), 140.7 (m), 141.4 (m), 144.5

(m) (C6F5). I9F N M R (376 .30 MHz, CEDE): 5 -90.4 (s, ortho-F), - 1 0 3 . 0 (t, J =

22.2 Hz, meta-Y), -110.2 (s, para-V). Anal. Found: C, 50.86; H, 4.05; N, 7.43

0/0. Calc. for C32H28N4F10K2O2： C, 49.99; H, 3.67; N, 7.29 %.

21

1.7 References for Chapter 1

1. (a) Lappert, M. F; Power, P. P.; Sanger, A. R.; Srivastava, R. C. Metal and

Metalloid Amides-, Ellis-Horwood: Chichester, 1980, p.235-381, 465-544.

(b) Fryzuk, M. D.; Montgomery, C. D. Coord. Chem. Rev. 1989, 95, 1-40.

2. Kempe, R. Angew. Chem. Int. Ed 2000，59, 468-493.

3. Frankland, E. Proc. Roy. Soc. 1856-7, 8, 502.

4. (a) Burger, H.;Wannagat, U. Monatsh. Chem. 1963, 94, 1007-1012.

(b) Burger, H.;Wannagat, U. Monatsh. Chem. 1964, 95, 1099-1102.

5. Andersen, R. A.; Faegri, K.; Green, J. C.; Haaland, A.; Lappert, M. R; Leung,

W.-R; Rypdal, K. Inorg. Chem. 1988, 27, 1782-1786.

6. Bradley, D. C.; Ghotra, J. S.; Hart, F. A.; J. Chem. Soc., Da/ton Trans. 1973,

1021-1023.

7. Bryndza, H. E.; Tarn, W. Chem. Rev. 1988, 88, 1163-1188.

8. Roundhill, D. M. Chem. Rev. 1992, 92, 1-27.

9. Holm, R. H.; Kennepohl, P.; Solomon, E . I. Chem. Rev. 1996, 96, 2 2 3 9 - 2 3 1 4 .

10. (a) Bradley, D. C.; Hursthouse, M. B.; Smallwood, R. J.; Welch, A. J. J. Chem.

Soc., Chem. Commun. 1972, 872-873.

(b) Turculet, L.; Tilley, T. D. Organowetallics 2002’ 27, 3961-3972.

(c) Lam, C. H. M. Phil. Thesis, The Chinese University of Hong Kong, 2001.

22

(d) Kempe, R. Eur. J. Inorg. Chem. 2003，791-803.

(e) Jimehez, G; Royo, P.; Cuence, T. Organometallics 2002, 21, 2189-2195.

(f) Liang, L. C.; Chien, P. S. ； Lee, P. Y. Organometallics 2008, 27,

3082-3093.

11. (a) Barr, D.; Clegg, W.; Mulvey, R. E.; Snaith, R. J. Chem. Soc., Chem.

Commun. 1984, 469-470.

(b) Barr, D.; Clegg, W.; Mulvey, R. E.; Snaith, R. J. Chem. Soc., Chem.

Commun. 1984, 700-710.

(c) Engelhardt, L. M.; Jacobsen, G. E.; Junk, R. C.; Raston, C. L.; Skelton, B.

W.; White, A. H. J. Chem. Soc., Dalton Tram. 1988, 1011-1020.

(d) Engelhardt, L. M.; Jacobsen, G E.; Junk, R. C.; Raston, C. L.; White, A.

H. J. Chem. Soc., Chem. Commun. 1990, 89-91.

(e) Engelhardt, L. M.; Junk, P. C.; Patalinghug, W. C.; Sue, R. E.; Raston, C.

L.; Skelton, B. V; White, A. H. J. Chem. Soc., Chem. Commun. 1991，

930-932.

(f) Engelhardt, L. M.; Gardiner, M. G; Jones, C.; Junk, P. C.; Raston, C. L.;

White, A. H. J. Chem. Soc., Dalton Trans. 1996, 3053-3057.

(g) Henderson, K. W.; Mulvey, R. E.; Dorigo, A. E. J. Organomet. Chem.

1996, 518, 139-146.

(h) Raston, C. L.; Skelton, B. W.; Tolhurst, V. A.; White, A. H. Polyhedron

1998, 77, 9 3 5 - 9 4 2 .

(i) Raston, C. L.; Skelton, B. W.; Tolhurst, V. A.; White, A. H. J. Chem. Soc.,

Dalton Trans. 2000, 1279-1285.

(j) Liddle, S. T.; Clegg, W. J. Chem. Soc., Dalton Trans. 2001, 402-408.

23

(k) Liddle, S. T.; Clegg, W.; Morrison, C. A. Dalton Trans. 2004, 2514-2525.

12. (a) Polamo, M.; Leskela, M. J. Chem. Soc” Dalton Trans. 1996，4345-4349.

(b) Kempe, R.; Arndt, P. Inorg. Chem. 1996, 35, 2644-2649.

(c) Kempe, R.; Brenner, S. Arndt, P. Organometallics, 1996’ 15, 1071-1074.

(d) Fuhrmann, H.; Brenner, S.; Arndt, P.; Kempe, R. Inorg. Chem. 1996, 35,

6742-6745.

(e) Polamo, M.; Leskela, M. Acta Chem. Scand 1997, 57, 69-72.

(f) Oberthur, M.; Hillebrand, G; Arndt, P.; Kempe, R. Chern. Ber. 1997, 130,

789-794.

(g) Cotton, F. A.; Daniels, L. M.; Jordan IV, G T. Chem. Commun. 1997,

421-422.

(h) Spannenberg, A.; Tillack, A.; Arndt, P.; Kirmse, R.; Kempe, R.

Polyhedron 1998, 77, 845-850.

(i) Cotton, F. A.; Daniels, L. M.; Murillo, C. A.; Pascual, I. Inorg. Chem.

Commun. 1998, 1-3.

(j) Morton, C.; O'Shaughnessy, P.; Scott, P. Chem. Commun. 2000,

2099-2100.

(k) Lee, H. K.; Peng, Y.; Kui, S. C. F.; Zhang, Z. Y; Zhou, Z Y; Mak, T. C.

W. Em J. Inorg. Chem. 2000 , 2 1 5 9 - 2 1 6 2 .

(1) Lee, H. K.; Wong, Y. L.; Zhang. Z. Y.; Ng, D. K. P.; Mak, T. C. W. J. Chem.

Soc., Dalton Trans. 2000, 539-544.

(m) Lee, H. K.; Lam, C. H.; Li, S. L.; Zhang, Z. Y.; Mak, T. C. W. Inorg.

Chem. 2001，40, 4691-4695.

24

13. (a) Spannenberg, A.; Arndt, P.; Kempe, R. Angew. Chem. Int. Ed 1998, 37,

832-835.

(b) Kempe. R.; Noss, H.; Irrgang, T. J. Organomet. Chem. 2002, 647, 12-20.

(c) Baldamus, J.; Cole, M. L.; Helmstedt, U.; Hawkins, E. M. H.; Jones, C.;

Junk, P. C.; Lange, R; Smithies, N. A. J. Organomet. Chem. 2003, 665, 33-42.

(d) Cole, M. L.; Junk, P. C. New. J. Chem. 2003, 27, 1032-1037.

(e) Kui, S. C. R; Li, H. W.; Lee, H. K. Inorg. Chem. 2003, 42, 2824-2826.

(f) Kempe, R. ； Scott, N. M.; Eur, J. Inorg. Chem. 2005, 1319-1324.

14. (a) Banks, R. E.; Smart, B. E.; Tatlow, J. C. Organofluorine Chemistry:

Principles and Commercial Applications; Plenum: New York, 1994.

(b) Hiyama, T. Organofluorine Compounds, Springer: Berlin, 2000.

(c) Shutov, P. L.; Karlov, S. S.; Harms, K.; Tyurin, D. A.; Sundermeyer, J.;

Lorberth, J.; Zaitseva, G S. Eur. J. Inorg. Chem. 2004, 2498-2503.

15. Lee, W. Y; Liang, L. C. Inorg. Chem. 2008, 47, 3298-3306.

16. (a) Bear, J. L.; Li, Y.; Han, B.; Caemalbecke, E. V; Kadish, K. M. Inorg.

Chem. 1997 , 36, 5 4 4 9 - 5 4 5 6 .

(b) Kadish, K. M.; Phan, T. D.; Giribabu, L.; Caemalbecke, E. V; Bear, J. L.

Inorg. Chem. 2003, 42, 8663-8673.

17. Click, D. R.; Scott, B. L.; Watkin, J. G Chem. Commun. 1999, 633-634.

18. Giesbrecht, G. R.; Gordon, J. C.; Clark, D. L.; Hijar, C. A.; Scott, B. L.;

Watkin, J. G. Polyhedron 2003, 22, 153-163.

25

19. (a) Nomura, K.; Schrock, R. R.; Davis, W. M. Inorg. Chem. 1996, 55,

3695-3701.

(b) Schrock, R. R. ； Cummins, C. C.; Wilhelm. T.; Lin, S.; Reid, S. M.; Kol,

M.; Davis, W. M. Organometallics 1996, 15, 1470-1476.

(c) Neuner, B.; Schrock, R. R. Organometallics 1996, 15, 5-6.

(d) Rosenberger, C.; Schrock, R. R.; Davis, W. M. Inorg. Chem. 1997, 36,

123-125.

(e) Seidel, S. W.; Schrock, R. R.; Davis, W. M. Organometallics 1998’ 77,

1058-1068.

(f) Reid, S. M.; Beuner, N.; Schrock, R. R.; Davis, W. M. Organometallics

1998, 77,4077-4089.

(g) Cochran, F. V.; Bonitatebus, P. J.; Schrock, R. R. Organometallics 2000,

19, 2414.

(h) Greco, G R; O'Donoghue, P. B.; Seidel, S. W.; Davis, W. M.; Schrock, R.

R. Organometallics 2000, 19, 1132.

20. Tellmann, K. P.; Gibson, V. C.; White, A. J. P.; Williams, D. J.

Organometallics 2005, 24, 280-286.

21. Koppang, R. J. Organomet. Chem. 1972, 46, 193-200.

22. Kui, S. C. F. M. Phil Thesis, The Chinese University of Hong Kong, 2001.

26

CHAPTER 2 Zirconium(IV)，Vanadium(III) and

Chromium(III) Complexes Derived from the

[N(C6F5)(2-C5H3N-6-Me)]- Ligand

2.1 An Overview on Zr(IV), V(III) and Cr(III) Complexes

Supported by 2-Pyridyl Amido Ligands

Early research focus was the chemistry of cyclopentadienyl ligands with

special interest devoted to Group 4 metallocenes, which showed high activities in

polymerization and activation of small molecules. Later, development of amido

ligands attracted an increasing research interest as an alternative of

cyclopentadienes. Amido ligands have been widely investigated to stabilize

early, electron-poor transition metals in medium or high oxidation states. In

1935, the first early transition metal amide [Ti(NPh2)4] was reported]

Studies of Group 4 metal amides have attracted considerable attention due to

their potential applications in olefin polymerization.^'^® There are several

methods for the preparation of Group 4 metal amides, such as transmetallation

with the use of alkali metal amides, transamination or direct synthesis from the

metal chloride and ligand precursor to eliminate HCl. Bradley and co-workers

have reported a series of zirconium(IV) complexes supported by a dialkylamido

ligand and the bulky bis(trimethylsilyl)amido (Equation 2—1)."

27

4 LiNR, ， ， … � Zr(NR2)4

4 Li[N(SiMe3)2] MeLi ^^ Zr[N(SiMe3)2]3CI 丨 • • > Zr[N(SiMe3)2]3Me

Equation 2-1

In the last decade, the chemistry of 2—pyridyl amido ligands has attracted

much attention. Zr(IV) complexes supported by 2-pyridyl amido ligands of

different steric bulkiness have been reported by several research groups. By

reacting A/-phenyl substituted 2-aminopyridine with ZrCU, Polamo and Leskela

have successfully prepared the binuclear [Zr(L^^)2(Cl)(//-Cl)]2 (l/h =

N(Ph)(2-C5H4N)) complex (Scheme 2-1).^^

Fh .. r ^ CI N ^

f ^ ^ 2 equiv. ZrCU ^ N - ^ \ \ \ 4 equiv. \\ ] [ j ) 一 > Z r z N � P h

^ N ^ N ^ ^ ^ toluene, reflux P h - N - ^ \ \ c r

H > N \a k A 7 O ph, V

Scheme 2-1

Since 1996, Kempe and co-workers have reported a series of early transition

metal complexes supported by r|^-bound aminopyridinato ligands (Chart 2-1).^' ^

28

MegSi� N

R 尸 N,

\ / R—Zr—NHEto

/ \ CI CI

R = CI, NEt,

y N N SiMea MesSr 丫 飞

R = CI, Me, Ph, C=CPh, C=CSiMe3, C=CC=CSiMe3

Kempe et.d.�

R' = H, R = Me, X = CI R = R' /-Pr, X = Cl/Me

Chart 2-1

Using the very bulky A/-adamantyl-2-aminopyridinato ligand, Scott and

co-workers have successfully synthesized bis(aminopyridinato) complexes of the

type [ZVL2X2] (X= CI, NMe2, CHiPh, CHjBu') with a better control of the

zirconium/ligand stoichiometry and the incorporation of more sterically

demanding ligands (Scheme 2-2) ."

2 equiv. R入N人

2 N

H

ZrX, Q

\ /

A d - N

R

X

tj X

-R

Scheme

R = H/Me X = CI, NMe2, CH2Ph,

CH2-胁/-butyli5

Recently, Jones and co-workers have also reported a mononuclear Zr(IV)

triamide complex, which was readily prepared by the reaction of ZrCU with

Li[N(SiMe3)(2-C5H3N-6-Me)](Et20) in diethyl ether (Scheme 2-3). 13

29

n SiMes Et20, 0°C 广N N \ / Li

I OEt,

1/3 equiv ZrCU Et,0

f Y ^ a 尹 Me3

N——Zr-M /) MeaSi / \ \ J

v O N 厂

Scheme 2-：

Other than the Group 4 metal amides, chemistry of vanadium(II) and

vanadium(III) amido complexes has attracted the interest of researchers in the past

decades because of their ability to activate small molecules such as dinitrogen?

The reactivity is initiated by the presence of the two or more ^/-electrons on the

metal center. Early work involved the use of the [N(SiMe3)2r Hgand, which led

to the homoleptic V(III) tris(amido) complex [V{N(SiMe3)2}3].i7 In 1994,

Gambarotta and co-workers have reported the reactivity of vanadium(III) amides

supported by [LiNRi]" (R = 'Pr, Cy, or Ph).'^ The first well characterized

vanadium complex supported by aminopyridine was reported by Gambarotta et

al.i9 Kempe and co-workers have reported a vanadium(III) triamide complex by

employing the monoanionic [N(SiMe3)(2-C5H3N-4-Me)]~ ligand (Chart 2 - 2 ) . 丄 之 。

thf Me I

N.

RoN NRo

( V v^ N -N

Me,

MegSi \ .N

R = 'Pr, Cy, Ph

Gambarotta et. al.

MegSrN 丫N ) \ I

Kempe et. a/.以

Chart 1-i

30

R = Me, Et and 'Pr

MegSi MesSi z

N 一 C r N-S iMe.

MegSi

MegSi N—SiMe.

�N—CfZ \ N-

Homoleptic Cr(III) complexes derived from dialkylamido ligands, [Cr(NR2)3]

(R = Me, Et and 'Pr), were reported by Abel and co-workers, �20-22 Using the

more bulky [N(SiMe3)2]~ ligand, Burger and Wannagat have successfully

prepared the homoleptic [Cr{N(SiMe3)2}3] complex?�Cr(I I I ) complex of the

[N(SiMe3)(2-C5H3N-4-Me)]" ligand was prepared and structurally characterized

by Kempe and co-workers/^'' The latter complex is isostructural to its V(III)

analogue (Chart 2-3).

Abel et a/. 17，2022

MegSi .N 0 /

l rij—c〈一 N � 狐

MesSi / \

N � . N -

Kempe et a / ^

Chart 2-：

Burger et a/

31

<

2 /

//

2

R N

NR <

2.2 Recent Results from our Group

Recently, a few early transition metal complexes supported by the

[N(SiBu'Me2)(2-C5H3N-6-Me)]" ligand were prepared and structurally

characterized by our group (Chart The Zr(IV) and Cr(III) complexes

are mononuclear. X-Ray crystallography revealed that the Zr(IV) complex

consists of three bidentate [N(SiBu'Me2)(2-C5H3N-6-Me)]' ligands. Attempts

to substitute the remaining chloride ligand in order to prepare the corresponding

tetra(amido) species have been unsuccessful. The V(III) complex was isolated

as a binuclear compound. Each V(III) center is bound by two

[N(SiBu'Me2)(2-C5H3N-6-Me)]- ligands and two bridging chloride ligands.

SiBu^Me, V\ MezBu Si' Z r - N

(\ N �

�SBi/Me2

� 1 MesBi/Si�

Me2BL/Si�N/^N R N-

d S 旧 i /Me

/ \ f(l .N^SiBu'Mej

Me2Bi/Si�l/^N � 令 / S旧i/Me2

V r - N

SiBu'Me,

Chart

32

2.3 Objectives of this work

Recently, a number of early transition metal complexes derived from

2-pyridyl amido ligands have been prepared by others and our group. These

works were focused on the use of 2-pyridyl amido ligands containing bulky

substituents. However, reports on early transition metal complexes supported by

amido ligands with electron-withdrawing substituents are rare. It is expected

that the highly electron-withdrawing [N(C6F5)(2-C5H3N-6-Me)]" (L^^^^) ligand

may form stable transition metal complexes with interesting structural and

reaction chemistry. In this chapter, we describe the synthesis and structures of

Zr(III), V(III) and Cr(III) complexes derived from the ligand.

33

3/2 equiv

A Z n 人 N'CeFs I

；N

S CeFs

\ /\

A / K / N：

N： \ 广I

ZrCl

toluene, r.t, 8h

Scheme 2-^

C7H8

The same reaction conditions were applied to prepare the vanadium(III)

derivative. Treatment of VCl3(thf)3 with 3/2 equivalents of 2 under an identical

reaction condition yielded the corresponding V(III) triamide as dark red

crystals in 60% yield (Scheme 2-5). The V(III) triamide is readily soluble in

toluene and thf. Unfortunately, good quality crystals of complex 5 suitable for

X-ray crystallographic analysis could not be obtained. Nevertheless, results of

34

2.4 Synthesis and Structures of Tris(amido) Complexes of

Zr(IV), V(III) and Cr(III)

2.4.1 Synthesis of • C,Hs\ ( 4 ) ， ( 5 ) and

[Cr(LC6F5)3j (6)

The reaction of 3/2 equivalents of [{K(L^^^^)(tmeda)}2] (2) with anhydrous

ZrCU in toluene at ambient temperature yielded [Zr(L^^^^)3(Cl)«C7H8] (4) as

fluorescent yellow crystals in 80% yield (Scheme 2-4). The presence of one

toluene solvate molecule has been confirmed by X-ray crystallography, NMR

studies and as well as elemental analysis.

F

F

ciN. F

OF

f x ( 少N F \ CI

人 N [ N'

人 : � �

F

4 80%

elemental analysis were consistent with the formulation of the complex.

A ^ N N'CsFS I \

3/2 equiv /

N： V C I v 3 t h f

C«F=

N；

\ ‘

toluene, r.t., 8h

V(LC6F5)3

5 60%

Scheme 2-5

Attempts to react CrCb with 3/2 equivalents of 2 in toluene at room

temperature were unsuccessful. Only the starting materials were recovered after

the reaction. The reaction was then repeated in the same solvent at 40

Under the latter reaction conditions, the (6) complex was successfully

synthesized in 40% yield (Scheme 2-6).

n ^ N N'C6F5 I \

CrCl3 toluene, r.t., 8h

:N 3/2 equiv > ' \ /

/ N-

CrF 广 V ( 7 �

CrClg

toluene, 40°C. 8h

Scheme 2-6

No reaction

6 40%

35

Attempts to prepare a Cr(II) derivative of the ligand by the reactions of

CrCl2 with the potassium amide 2 in toluene were unsuccessful. Only the

starting material [K(L^^^^)(tmeda)]2 (2) was recovered after the reactions at both

room temperature and 40 °C. Previous results in our group have shown that the

reaction of CrCb with Li[N(SiBu'Me2)(2-C5H3N-6-Me)](tmeda) only led to the

23 corresponding Cr(III) tris(amide).

Complex 4 was characterized by NMR, elemental analysis as well as X-ray

crystallography. The ^H and ^ C NMR of complex 4 showed one set of

resonance signals due to the ligand. The ^H NMR spectra of the compound

shows a singlet resonance signal at 2.05 ppm, which is assignable to the 6-Me

substituent of the ligand. The pyridyl protons show three sets of signals at

5.5-6.8 ppm. The toluene solvate molecule elicits two signals at 2.12 and

7.0-7.2 ppm. Three resonance signals were obtained on the ^ F NMR spectrum

of the complex, which were assignable to the ortho-, meta- and para—substituted

fluorine atoms on the C6F5 ring.

Complexes 5 and 6 are paramagnetic. The solution magnetic moments of

the complexes were determined by the Evans NMR method in toluene solutions at

298K. Their magnetic moments are consistent with a high-spin electronic

configuration for V(III) and Cr(III), respectively. Table 2-1 lists some physical

properties of these compounds.

36

Table 2-1 Some physical properties of compounds 4-6

Compound Yield (%) Colour M.P. CQ Magnetic

moment (HB)

4 80 fluorescent yellow crystals 205-208 (dec) diamagnetic

5 60 dark red crystals 213-215 2.91

6 40 dark green crystals 237-239 3.85

2.4.2 Molecular Structures of [Zr(L^^^ )3(Cl)*C7H8l (4)，and

[Cr(LC,3� (6 )

1. Molecular Structure of . CyHg] (4)

Compound 4 crystallizes in a monoclinic crystal system with the space group

C2/c. The Zr(IV) center is bound by three A^,A^-chelating ligands and one

terminal chloride ligand. In addition, one toluene solvate molecule is also

present. Figures 2-1 depicts the molecular structure of 4 with the

atom-numbering schemes. Selected bond distances (A) and angles (。）are listed

in Table 2-2.

The observed Zr-Namido bond distances of 2.190(4)-2.209(3) A in complex 4，

are shorter than the corresponding Zr-Npyridyi bond distances of 2.309(3)-2.342(3)

A . The Zr-Namido bond distances in complex 4 are longer than those of 2.17 A

(ave.) in [Zr{N(SiMe3)(2-C5H3N-6-Me)}3Cl]^^ and 2.174(5)-2.195(5) A in

[Zr{N(SiBu'Me2)(2-C5H3N-6-Me)}3Cl]23. The Namido-Zr-Npyndyi bite angles in

4 are 58.60(4)。，58.2(1)�and 58.6(1)。，which are slightly smaller than those in the

former two c o m p o u n d s . T h e Zr(l)-Cl(l) bond distance in 4 is 2.421(1) A.

37

Figure 2-1 Molecular structure of [Zr{N(C6F5)(2-C5H3N-6-Me)}3(CI)*(C7H8)] (4)

Thermal ellipsoids are plotted at 30% probability level.

38

Table 1-： Molecular structure of • CTHS] (4)

Zr � - N ( l ) 2.190(4) Z r � - N � 2.341(3) Zr � - N ( 3 ) 2.209(3) Zr(l)-N(4) 2.342(3) Zr � - N ( 5 ) 2.208(3) Zr(l)-N(6) 2.309(3) Z r � - C I � 2.421(1) N � - C � 1.383(6) N(2)-C(l) 1.347(6) N(1)-C(7) 1.391(6) N(3)-C(13) 1.369(5) N(4)-C(13) 1.354(6) N(3)-C(19) 1.382(5) N(5)-C(25) • 1.364(5) N(6)-C(25) 1.360(5) N(5)-C(31) 1.405(5)

N(l)-Zr(l)-N(2) 58.60(4) N(l)-Zr(l)-N(3) 147.4(1) N(l)-Zr(l)-N(5) 106.2(1) N(2)-Zr(l)-N(6) 135.1(1) N(3)-Zr(l)-N(2) 95.1 � N(3)-Zr(l)-N(4) 58.2(1) N(3)-Zr(l)-N(5) 86.6(1) N(4)-Zr(l)-N(6) 133.9(1) N(5)-Zr(l)-N(6) 58.6(1) N(2)-Zr(l)-Cl(l) 84.97(9) N(4)-Zr(l)-Cl(l) 137.8(1) N(5)-Zr(l)-Cl(l) 130.7(1) N(6)-Zr(l)-Cl(l) 85.24(9) C(l)-N(l)-Zr(l) 99.1(3) C(7)-N(l)-Zr(l) 138.9(3) C(7)-N � - C � 120.4(4) N(l)-C(l)-N(2) 108.9(4)

39

2. Molecular Structure of (6)

Figures 2-2 depicts the molecular structure of 6 with the atom-numbering

schemes. Selected bond distances (A) and angles (。）are listed in Table 2-3.

Complex 6 crystallizes in a monoclinic crystal system with the space group

Plxln. The Cr(III) complex has a distorted octahedral geometry. The Cr(III)

center exhibits a distorted octahedral geometry with N(l), N(4), N(5), N(6)

forming the equatorial plane, whereas N(2) and N(3) occupying the axial positions.

Each lC6F5 ligand is coordinated to the Cr(III) center in a A ，A —chelating fashion,

resulting in a highly strained four-member b r N o J metalacycle ring. The

observed Cr-Namido bond lengths are 2.000(2), 2.011(2) and 2.019(2) A, whereas

the Cr-Npyridyl distances are 2.066(2), 2.069(2) and 2.072(2) A. The Cr-Namido

bond distances in 6 are shorter than those of 2.056(6)-2.079(5) A reported for the

closely related [Cr{N(SiMe3)(2-C5H3N-4-Me)}3]^^' and 2.069(2)—2.078� k for

[Cr{N(SiBu^Me2)(2-C5H3N-6-Me)}3]''. The shorter Cr-Namido distances in

complex 6 may be ascribed to the sterically less demanding ligand as

compared to the silylated derivatives [N(SiMe3)(2-C5H3N-4-Me)]" and

[N(SiBu'Me2)(2-C5H3N-6-Me)r.

The Namido-Cr-Npyridyibite angles in 6 are 64.87(9)°, 64.89(8)�and 65.24(8)�,

which are similar to those in [Cr{N(SiBu'Me2)(2-C5H3N—6-Me)}3]23, but are

smaller than those in [Cr{N(SiMe3)(2-C5H3N-4-Me)}3]^^'

40

Figure 2-2 Molecular structure of [Cr{N(C6F5)(2-C5H3N-6~Me)}3�(6)

Thermal ellipsoids are plotted at 30% probability level.

41

Table 2-3 Molecular structure of [Cr{N(C6F5)(2-C5H3N-6~Me)}3] (6)

Cr(l)-N � 2.011(2) Cr(l)-N(2) 2.072(2) Cr(l)-N(3) 2.019(2) Cr(l)-N(4) 2.069(2) Cr(l)-N(5) 2.000(2) Cr(l)-N(6) 2.066(2) N � - C � 1.356(3) N(2)-C(l) 1.360(4) N � - C ( 7 ) 1.387(3) N(3)-C(13) 1.355(3) N(4)-C(13) 1.358(3) N(3)-C(19) 1.398(3) N(5)-C(25) 1.354(3) N(6)-C(25) 1.354(3) N(5)-C(31) 1.397(3)

N(l)-Cr(l)-N(2) 64.87(9) N(l)-Cr(l)-N(4) 92.37(9) N(l)-Cr(l)-N(5) 101.14(9) N(2)-Cr(l)-N(4) 100.24(8) N(2)-Cr(l)-N(6) 100.94(8) N(3)-Cr(l)-N(4) 64.89(8) N(3)-Cr(l)-N(5) 102.45(9) N(3)-Cr(l)-N(6) 95.26(9) N(4)-Cr(l)-N(6) 103.76(9) N(5)-Cr(l)-N(6) 65.24(8) C(l)-N(l)-Cr(l) 95.2(1) N � - C O ) - N � 107.6(2) C(7)-N � - C r ( l ) 139.6(1) C(7)-N(l)-C(l) 124.9(2)

42

2.5 Experimentals for Chapter 2

Materials:

ZrCU and CrCb were purchased from Strem and used as received.

VCl3(thf)3 was prepared according to literature procedure.

General Procedures for the Preparation of Complexes 4-6

In a typical experiment, a Schlenk tube was charged with an appropriate

metal salt (ca. 2 mmol) and toluene (15 ml). To a slurry of the above mixture at

0 was slowly added a solution of [{K(L^^^^)(tmeda)}2] (2) (ca. 3 mmol) in the

same solvent (20 ml). The reaction mixture was stirred at room temperature (for

complexes 4 and 5) or at 40 (for complex 6) for 24h. The product mixture

was filtered through Celite, and concentrated to ca. 10 ml. Standing the solution

at room temperature afforded the desired products.

[Zr(LC6F5)3a • C7H8�（4). ZrCU： 0.47 g, 2.02 mmol;

[{K(LC6F5)(tmeda)}2]: 2.57 g, 3.00 mmol. Yield: 1.66 g, 80%. M R: 205-208

oc (dec). 1 h N M R (300.13 MHz, CeDe): 5 2.05 (s, 9 H, Me), 2.12 (s, 2 H, CVRG)

5.55 (d, J= 8.4 Hz, 1 H, C5H3N), 5.78 (d, J= 12 Hz, 1 H, C5H3N), 6.73 ( t , J = 7.8

Hz, 1 H, C5H3N), 7.01-7.14 (m, 2 H, CvHs). ^ C NMR (75.47 MHz, CsDs): 5

21.4 (Me overlapping with O/疋6H5), 103.3, 113.7, 141.8, 154.2, 166.0 (C5H3N),

136.6 (m), 139.9 (m), 141.2 (m), 144.4 (m) (C6F5), 125.7, 128.6, 129.3, 137.9

(CvHg). I9f NMR (376.30 MHz, CsDs): 5 -81.9 (s, ortho-V\ -99.1 (s, para-V\

-100.8 (s, meta-¥). Anal. Found: C, 49.86; H 2.47; N, 8.50 %. Calc. for

C36H18N6F15CIZPC7H8： C, 49.74; H, 2.52; N, 8.09 %.

43

V(lC6F5)3 (5). VCl3(thf)3： 0.75 g, 2.01 mmol; [{K(L^^^^)(tmeda)}2]: 2.57 g, 3.00

mmol. Yield: 1.04 g, 60%. M.P.: 213-215 X. Anal. Found:

C, 49.54; H 2.02; N, 9.73 %. Calc. for CaeHigNeFisV: C, 49.67; H, 2.08; N, 9.65

%.

[Cr(LC6F5)3�(6). CrCb： 0.32 g, 2.02 mmol; [{K(L^'^')(tmeda)}2]: 2.57 g, 3.00

mmol. Yield: 0.70 g, 40%. M R: 237-239 X. i eff =3.85 Anal. Found:

C, 49.52; H 1.99; N, 9.72 %. Calc. for CaeHigNgFisCr: C, 49.61; H, 2.08; N,

9.64 %.

44

2.6 References for Chapter 2

1. Dermer, O. C.; Fernelius. W. C. Z Anorg. Chem. 1935’ 221, 83.

2. (a) Kempe, R. Angew. Chem. Int. Ed 2000, 39, 468-493.

(b) Kempe, R. Eur. J. Inorg. Chem. 2003, 791-803.

(c) Fuhrmann, H.; Brenner, S.; Arndt, P.; Kempe, R. Inorg. Chem. 1996’ 35,

6742-6745.

3. (a) Scollard，J. D.; McConville, D. H.; Payne, N. C.; Vittal, J. J.

Macromolecules 1996，29, 5241-5243.

(b) Scollard, J. D.; McConville, D. H. J. Am. Chem. Soc. 1996, 118,

10008-10009.

4. Shah, S. A. A.; Dorn, H.; Voigt, A.; Roesky, H. W.; Parisini, E.; Schmidt, H.

G. ； Noltemeyer, M. Organometallics 1996, 15, 3176-3181.

5. Mack, H.; Eisen, M. S. J. Organomet. Chem. 1996, 525, 81-87.

6. Baumann, R.; Davis, W. M.; Schrock, R. R. 1 Am. Chem. Soc. 1997，JJ9,

3830-3831.

7. (a) Gibson, V. C.; Kimberley, B. S.; White, A. J. P.; Williams, D. J.; Howard,

P. Chem. Commun. 1998, 313-314.

(b) Britovsek, G J. P.; Gibson, V. C.; Wass, D. F. Angew. Chem. Int. Ed 1999，

38, 428-477.

(c) Gibson, V. C.; Spitzmesser, S. K. Chem. Rev. 2003, J03, 2 8 3 - 3 1 5 .

45

8. (a) Deelman, B. J.; Hitchcock, P. B.; Lappert, M. R; Leung, W. P.; Lee, H. K.;

Mak, T. C. W. Organometallics 1999, 18, 1444-1452.

(b) Daniele, S.; Hitchcock, P. B.; Lappert, M. R; Merle, P. G. J. Chem. Soc”

Dalton Trans. 2001, 13-19.

(c) Love, J. B.; Clark, H. C. S.; Cloke, F. G N.; Green, J. C ; Hitchrock, P. B.

J. Am. Chem. Soc. 1999, 121, 6843-6849.

9. Gade, L. H. Chem. Commun. 2000, 173-181.

10. (a) Mehrkhodavandi, P.; Bonitatebus Jr., P. J.; Schrock, R. R. J. Am. Chem.

Soc. 2000, 122, 7841-7842.

(b) Mehrkhodavandi, P.; Schrock, R. R. J. Am. Chem. Soc. 2001, 123,

10746-10747.

(c) Mehrkhodavandi, P.; Schrock, R. R.; Bonitatebus Jr., P. J. Organometallics

2002, 27, 5785-5798.

(d) Mehrkhodavandi, P.; Pryor, L. L.; Schrock, R. R. Organometallics 2003,

22, 4569-4583.

(e) Tonzetich, Z. J.; Schrock, R. R. Polyhedron 2006, 469-476.

11. (a) Bradley, D. C.; Thomas, I. M. J. Chem. Soc. 1960, 3857-3861.

(b) Clark, R. J. H.; Bradley, D. C.; Thornton, P. Comprehensive Inorganic

Chemistry: Ch. 32-33, The Chemistry of Titanium, Zirconiiim and Hafnium,

Pergamon Press, Oxford, 1973.

12. (a) Kempe. R.; Brenner, S.; Arndt, P. Organometallics, 1996，75, 1071-1074.

(b) Kempe, R.; Arndt, P. Inorg. Chem. 1996’ 55, 2644-2649.

46

(c) Spannenberg, A.; Tillack, A.; Arndt, P.; Kirmse, R.; Kempe, R. Polyhedron

1998, 17, 845-850.

(d) Kretschmer, W. P.; Hessen, B.; Noor, A.; Scott, N. M.; Kempe, R. J.

Organomet. Chem. 2007, 692, 4569-4579.

13. Jones, C.; Junk, P. C.; Leary, S. G; Smithies, N. A. Inorg. Chem. Commun.

2003，6, 1126-1128.

14. Polamo, M.; Leskela, M. J. Chem. Soc., Dalton Tram. 1996, 4345-4349.

15. (a) Morton, C.; O'Shaughnessy, P. N.; Scott, P. Chem. Commun. 2000,

2099-2100.

(b) O'Shaughnessy, P. N.; Gillespie, K. M.; Morton, C.; Westmoreland, I.;

Scott, P. Organometallics 2002，21, 4496-4504.

(c) Westmoreland, I.; Munslow, I. J.; O'Shaughnessy, P. N.; Scott, P.

Organometallics 2003, 22, 2972-2976.

16. Clancy, G P.; Clark, H. C. S.; Clentsmith, G K. B.; Coke, F. G. N.; Hitchcock,

P. B. J. Chem. Soc., Dalton Trans. 1999, 3345-3347.

17. (a) Alyea, E. W.; Bradley, D. C.; Lappert, M. R; Sanger, A. R. J. Chem, Soc.,

Chem. Commun. 1969, 1064-1065.

(b) Bradley, D. C.; Copperthwaite, R. G J. Chem. Soc., Chem. Commun. 1971，

764.

(c) Alyea, E. W.; Bradley, D. C.; Copperthwaite, R. G. J. Chem. Soc., Dalton

Trans. 1972, 1580-1584.

47

18. Song, J. I.; Berno, P.; Gambarotta. S. J. Am. Chem. Soc. 1994, 116,

6927-6928.

19. Edema, J. J. H.; Gambarotta, S.; Meetsma, A.; Spek, A. L.; Veldman, N. Inorg.

Chem. 1991, 30, 2062-2066.

20. (a) Burger, H.; Wannagat, U. Monatsh. Chem. 1963, 94, 1007-1012.

(b) Burger, H.; Wannagat, U. Monatsh. Chem. 1964, 95, 1099-1102.

21. Abel, E. W.; Armitage, D. A.; Brady, D. B. Trans. Faraday Soc. 1966, 62,

3459.

22. Sr Wilkinson, G; Gillard, R. D.; McCleverty, J. A. Comprehensive

Coordination Chemistry: the synthesis, reactions, properties and applications

of coordination compounds, Pergamon Press, Oxford, 1987, 3, 835-837.

23. Lam, P. C. M Phil. Thesis, The Chinese University of Hong Kong, 2006.

24. Lee, H. K.; Cheng, P. S.; unpublished work.

48

CHAPTER 3 Manganese(II), Iron(II)，Cobalt(II)

and Nickel(II) Complexes of the

[N(C6F5)(2-C5H3N-6-Me)]- Ligand

3.1 A Brief Review on Amides of the Late Transition Metals

The chemistry of the late transition metal amides has received relatively less

attention when compared to that of the early transition metal counterparts. Late

transition metal centers are regarded as "soft", which makes their combination

with the "hard" amido ligands unfavourable.''^ Moreover, a Tc-conflict between

the lone-pair electron density on the amido nitrogen and the <i-electron-rich

metal center may cause the metal-nitrogen bond highly reactive (Chart 3-l).i’4

oi

c^l、

M N. � R

Chart 3-1

In order to stabilize the reactive metal-nitrogen bond, sterically demanding

amido ligands were employed in the early studies of late transition metal amides.

Early examples of late transition metal amides were mainly supported by silylated

amido ligands. Divalent manganese and cobalt amides, supported by the

bis(trimethylsilyl)amido ligand [N(SiMe3)2]", were reported by Burger and

Wannagat in the Later, Power and co-workers reported the molecular

structures of the Mn(II) and Co(II) derivatives [M{N(SiMe3)2}2]2 (M = Mn, Co),

49

as well as the Fe(II) counterpart (Chart 3-2, left) 5c-5e

MesSi� �SiMe3

MesSi/,, / N \ ���SiMe: "n—M M—N；

N SiMe3 / • �

MegSi SiMeg

Burger and Wannagat M = Mn, Co Lappert ef al. M = Fe

Ref. 5c-5e

Power et al. M = Mn, Fe, Co Ref. 6

Chart 3-2

Beside the bis(trimethylsilyl)amido ligand, the sterically more demanding

bis(diphenylmethylsilyl)amido ligand was also shown to be capable of stabilizing

two-coordinate Mn(II), Fe(II) and Co(II) complexes of the type

[M{N(SiMePh2)2}2] (M = Mn, Fe, Co) (Chart 3-2, right).'

Attempts to prepare homoleptic divalent nickel derivative by reacting Nil:

with Na[N(SiMe3)2] were unsuccessful 7a Only the Ni(I) amide

[Ni{N(SiMe3)2}(PPh3)2] was isolated (Chart 3-3) 7b

( S i M e 3 ) 2 N — — N i： ������PPh3

Ref. 7b

Chart 3-3

'PPh.

50

n o

/V -

Av

6,6

Av c^

Ln Nd, n La, n :

r.t., 8h

[Li(thOn]

-S i -N N' [(dme)NiCl2] � � .

‘ J \ J / 力 、 卞

Si-

. N ^ N - S i -

[(cocORCy r.t., 8h

- S i - N N' / \ /

O Pt \ / \ -Si-N^

Scheme 3-1

51

3.2 Examples of Late Transition Metal Complexes

Supported by 2-Pyridyl Amido Ligands

While the chemistry of early transition metal amides has been extensively

studied, reports on late transition metal amido complexes are rare. Kempe and

co-workers have reported a few of Group 10 metal complexes supported by

2-pyridyl amido ligands, which showed different coordination modes (Chart

3-4).8

Chart 3-4

In addition to transmetallation method, Kempe and co-workers have also

reported the preparation of late transition metal bis(amido) complexes using

lanthanide complexes as a ligand transfer reagent (Scheme 3-1).^

S i -\

O /

Si -

sp

- S i /

O \

—Si I

SiM(

N

\

N SiM(

N

N

n \ N

N.

K \ , r u

MESSJZ Y ’

< > fi

SiM(

N < MeaSi

a

V/

K \

/

Bu

N \

N

But\ N < c

MezBu'Si N N / ^ M八 MeoBu'Si, / = \

N H . / )

K . SiBu'Me.

fi /N~SiBu'Me2

n MejBu'Si^Kl^N^

\ / Fe

Z \

M = Co. Fe Ref. 10a

10b

R A / Ni\ R

/ N'

N y S

R = SiMes, Si'BuMej Ref. 12

Chart 3-5

52

A few divalent transition metal complexes supported by sterically demanding

2-pyridyl amido ligands have been successfully synthesized and characterized by

former members of our research group (Chart 3-5).^ Using the

trimethylsilyl-substituted [N(SiMe3)(2-C5H3N—6-R)]— (R = H, Me) ligand,

mononuclear Co(II) and Fe(II) complexes were successfully prepared and

structurally characterized. ” Using the more bulky

[N(SiBu'Me2)(2-C5H3N-6—Me)]- ligand, binuclear Co(II) and Fe(II) complexes

were isolated, in which a tmeda ligand binds to two metal centers in a

"，AM^inding rnode.^®^ In the absence of tmeda, a mononuclear Fe(II) amido

complex [Fe{N(SiBuMe2)(2-C5H3N-6-Me)}2] was p r e p a r e d . T h e latter

complex was found to be extremely sensitive to air. In addition to the 2-pyridyl

amido ligands, the closely related 8-quinolinyl amido ligands have also been

studied and the corresponding Ni(II) complexes [Ni{N(R)(8-CgHsN)}�](R :

SiMes, SiBu'Me2) were synthesized/^

N M

N

N-Si

c H,<3

--=

RM

M(

3.3 Objectives of our studies

The main objective of this part of our research work was focused on the

synthesis and structures of late transition metal complexes derived from the

[N(C6F5)(2-C5H3N-6-Me)r (L ^ ^ ) Hgand. A series of Co(II) and Fe(II)

complexes supported by the sterically bulky [N(R)(2-C5H3N-6-Me)]" (R = SiMes,

SiBu^Mei) ligands were synthesized by previous members of our research group.^

On the other hand, there is no systematic study on the chemistry of 2-pyridyl

amido ligands containing electron-withdrawing substituents. The highly

electron-withdrawing CePs substituent on the ligand can reduce the electron

density on the amido nitrogen atom, and thereby reduce the Tr-conflict between

the lone-pair electron density on the amido nitrogen and the t/—electron rich late

transition metal center.

53

Scheme 3-2

Complexes 7, 8, 9 and 10 were isolated as pale yellow, yellow, red and green

crystals, respectively. They are highly sensitive to air and moisture.

Complexes 7-10 are soluble in toluene and thf. The formulation of compounds

7-10 were confirmed by elemental analysis and their molecular structure

determined by single-crystal X-ray diffraction studies. Table 3-1 lists some

physical properties of the compounds.

54

3.4 Synthesis and Structures of Bis(amido) Complexes of

Mn(II), Fe(II), Co(II) and Ni(II)

3.4.1 Synthesis of [M(L"^^)2(tmeda)] [M = Mn (7)，Fe (8)，Co (9)，

Ni (10)]

The reaction of metal(II) dichlorides with one molar equivalent of

[K(LC6F5)(tmeda)]2 (2) in toluene at room temperature yielded the corresponding

metal(II) bis(amido) complexes 7-10 (Scheme 3-2).

广 N N'CsFS

MCI x X

A /

N；

( 7 �

toluene

r.t. 8h

广 N .

%%%%

o o o o

3 7 4 5

M

Table 3-1 Some physical properties of compounds 7-10

Compound Yield (%) Colour M.p. C Q Magnetic

moment (I B)

7 30 pale yellow crystals 254-256 5.96

8 70 yellow crystals 220-222 (dec) 5.12

9 40 red crystals 207-209 4.28

10 50 green crystals 237-238 (dec) 2.82

The solution magnetic moments of the complexes were determined by the

Evans NMR method in toluene solutions at 298K. The magnetic moments for

complexes 7-10 are consistent with a high-spin electronic configuration for

Mn(II), Fe(II), Co(II) and Ni(II), respectively.

As complexes 7-10 were isolated as tmeda-adducts, we attempted to prepare

the corresponding bis(amido) species in the absence of tmeda. In a separate

experiment, we attempted to react C 0 C I 2 with one molar equivalent of

[K(LC6F5)(thf)2]2 (3) under

reaction was observed and

reaction (Scheme 3-3).

an identical reaction condition,

only the starting materials were

Unfortunately, no

recovered after the

55

CoCl2

C<

I N

A /th " M �

t f

t h f \

thf

toluene

r.t., 8h No reaction

Scheme 3-3

It is believed that the basicity of the ligand in the tmeda-adduct

[K(LC6F5)(tmeda)]2 (2) is higher than that in (3). Therefore,

complex 2 behaves as a more reactive ligand-transfer reagent. This may account

for the inertness of the potassium salt 3 towards C 0 C I 2 .

56

3.4.2 Molecular Structures of Complexes 7-10

The molecular structures of complexes 7-10 were determined by

single-crystal X-ray crystallography. Figure 3—1 depicts the molecular structure

of complex 7, which is i so structural to that of 8-10. Selected bond distances (A)

and angles ( � ) of the four complexes are listed in Table 3-2 and Table 3-3.

Complexes 7-10 crystallize in a monoclinic crystal system with the space

group CUc. All complexes conform to a C2 symmetry with the metal center in

each complex being bounded by a pair ofL^^^^ ligands and a tmeda ligand.

The LC6F5 ligand binds in a 7V,7V-chelating manner, leading to a highly

strained MNCN metallacycle ring. The Namido-M-Npyridyi bite angles are acute:

59.98(9)�for 7, 61.4(3)�for 8, 62.7(3)�for 9 and 62.1(4)�for 10. The M-Namido

distances of 2.243(2) A for 7’ 2.210(3) A for 8 and 2.182(4) A for 9, which are

slightly shorter than the corresponding M-Npyndyi distances of 2.254(2) A for 7,

2.236(7) A for 8 and 2.202(8) A for 9, respectively. On the other hand, the

Ni - N a m i d o distance of 2.203(6) A is slightly longer than the corresponding

Ni-Npyridyi distance of 2.13(1) A, suggesting that the ligand in 10 may

behave as an aminopyridinato ligand.

Compared to the related [M{N(SiMe3)(2-C5H3N-6-Me)}2(tmeda)] (M = Co,

Fe) complexes, the M-Namido distances in complex 7-9 are longer than those of

the former complexes/^ This may be ascribed to the presence of the highly

electron-withdrawing C6F5 substituent in the LC6F5 ligand.

57

Figure 3-1 Molecular structure of [Mn{N(C6F5)(2-C5H3N-6~Me)}2(tmeda)�(7)

Thermal ellipsoids are plotted at 30% probability level. The ligand is two-fold

disordered and only one of the two possible orientations is shown for clarity.

58

Table 3-2 Selected bond distances (A) and angles (。）for complexes 7-8

[Mn{N(C6F5)(2-C5H3N-6~Me)}2(tmeda)�(7)

Mn(l)-N(l) Mn(l)-N(3) N(2)-C(l)

2.243(2) 2.362(3) 1.3900

Mn(l)-N(2) N(l)-C �

N � — C ( 7 )

2.254(2) 1.3900 1.4411

N(l)-Mn(l)-N(2) 59.98(9) N(2)-Mn(l)-N(2A) 106.2(1) N(1A)-Mn(l)-N(2) 97.8(1) C(l)-N(l)-Mn(l) 95.5(1) C(5)-N(2)-Mn(l) 145.7(1) N(l)-C(l)-N(2) 110.9(2)

N(l)-Mn(l)-N(3A) 93.3(1) N(3)-Mn(l)-N(3A) 77.3(2) N(1A)-Mn(l)-N(3A) 114.7(1) C(l)-N(2)-Mn(l) C(7)-N(l)-Mn(l) C(7)-N � - C �

93.5(1) 144.5(1) 119.2(1)

[Fe{N(C6F5)(2-C5H3N-6-Me)}2(tmeda)] (8)

Fe(l)-N(l) Fe � - N ( 3 ) N(2)-C �

2.210(3) 2.290(3) 1.39(1)

F e � - N �

N � - C �

N(1)-C(7)

2.236(7)

1.355(5)

1.382(5)

N(l)-Fe(l)-N(2) 61.4(3) N(2)-Fe(l)-N(2A) 100.2(7) N(1A)-Fe(l)-N(2) 96.5(4)

C(l)-N(l)-Fe(l) 94.3(2)

C(5)-N(2)-Fe(l) 145.0(7) N(l)-C(l)-N(2) 111.5(4)

N(l)-Fe(l)-N(3A) 113.7(1) N(3)-Fe(l)-N(3A) 79.3(1) N(1A)-Fe(l)-N(3A) 92.2(1) C(l)-N(2)-Fe(l) 92.2(5)

C(7)-N(l)-Fe(l) 146.3(3) C(7)-N(l)-C(l) 118.5(3)

59

Table 3-3 Selected bond distances (A) and angles (。）for complexes 9-10

[Co{N(C6F5)(2-C5H3N-6-Me)}2(tmeda)] (9)

Co(l)-N(l) Co � - N ( 3 ) N(2)-C(l)

2.182(4) 2.253(3) 1.40(1)

Co(l)-N(2) N � - C �

N(1)-C(7)

2.202(8)

1.357(6) 1.380(6)

N(l)-Co(l)-N(2) 62.7(3) N(2)-Co(l)-N(2A) 104.3(4) N(lA)-Co(l)-N(2) 96.6(3) C(l)-N(l)-Co(l) 93.7(3) C(5)-N(2)-Co(l) 148.0(8) N(l)-C(l)-N(2) 111.7(5)

N(l)-Co(l)-N(3) 113.4(1) N(3)-Co(l)-N(3A) 80.8(1) N(lA)-Co(l)-N(3) 91.8(1) C(l)-N(2)-Co(l) 91.7(5) C(7)-N(l)-Co(l) 147.0(3) C(7)-N(l)-C(l) 118.4(4)

[Ni{N(C6F5)(2-C5H3N-6~Me)}2(tmeda)] (10)

Ni(l)-N(l) Ni(l)-N(3) N(2)-C(l)

2.203(6) 2.174(4) 1.35 �

Ni(l)-N(2) N � - C �

N(1)-C(7)

2.13(1) 1.36 �

1.38(1)

N(l)-Ni(l)-N(2) 62.1(4) N(2)-Ni(l)-N(2A) 100.6(5) N(1A)-Ni(l)-N(2) 100.3(4) C(l)-N(l)-Ni(l) 91.3(5) C(5)-N(2)-Ni(l) 142.8(1) N(l)-C(l)-N(2) 111.3(9)

N(l)-Ni(l)-N(3A) 113.9(2) N(3)-Ni(l)-N(3A) 81.8(2) N(1A)-Ni(l)-N(3A) 86.3(2) C(l)-N(2)-Ni(l) 95.1(8) C(7)-N(l)-Ni(l) 149.6(6) C(7)-N(l)-C(l) 117.6(7)

60

2 FeCl2

广 N N'CEFS

:N

I �

\ X K

/

�N :

卜5 T I

toluene

r.t, 8h

Scheme 3-4

Attempts to prepare analogous Mn(II), Co(II) and Ni(II) derivatives have

been unsuccessful. Similar results have been reported on the coordination

chemistry of an unsymmetrical benzamidinate ligand

[(Me3Si)NC(C6H5)N(C6H3Me2-2,6)]-. In the latter studies, the direct reaction of

FeCb with one molar equivalent of [Li(L)(tmeda)] (L =

{(Me3Si)NC(C6H5)N(C6H3Me2-2,6)}) yielded the corresponding

[Fe(L)(Cl)(tmeda)]. Attempts to prepare the analogous mono(benzamidinate)

derivative of Mn(II), Co(II) and Ni(II) were unsuccessful.

61

3.5 Synthesis, Structure and Reactivity of a Mono(amido)

Fe(II) Complex

3.5.1 Synthesis of [Fe(L^^^ )(Cl)(tmeda)] (11)

Metathetical reaction of the dimeric potassium amide 2 with two molar

equivalents of FeCb in toluene afforded the mono-substituted

[Fe(LC6F5)ci(tmeda)] (11) in 80% yield (Scheme 3-4).

F

N'

N N

80%

F.

F

3.5.2 Physical Characterization of Compound 11

Compound 11 was characterized by melting point determination, magnetic

moment measurement and elemental analysis, in addition to single-crystal X-ray

diffraction studies. Table 3-4 lists some physical properties of the compound.

Table 3-4 Some physical properties of compound 11

Compound Yield (%) Colour M.p. C O

11 80 yellowish green crystals 176-180 (dec)

The structure of the complex as shown in Scheme 3-3 was confirmed by

X-ray crystallography. Result of elemental analysis was consistent with the

empirical formula of the complex. The magnetic moment of the complex was

found to be 4.94 HB by the Evans method at 298 K, which is consistent with a

high-spin dt electronic configuration for Fe(II).

3.5.3 Molecular Structures of Compound 11

Compound 11 crystallizes in an orthorhombic crystal system with the space

group Pl\l\l\. The amido ligand coordinates to the metal center in a

A^,A/'-chelating fashion. The Fe(II) center exhibits a distorted trigonal

bipyramidal geometry with N(l), N(3) and Cl(l) forming the equatorial plane,

whereas N(2) and N(4) occupying the axial positions. The Fe-Namido bond

distance of 2.088(1) A is shorter than the Fe-Npyndyi bond of 2.242(1) A, as

expected. The Fe-Namido bond distance in complex 11 is shorter than the

corresponding bond distance of 2.210(3) A in 8. This may be attributed to the

less crowded environment around the metal center in complex 11.

62

The Fe(l)-Cl(l) bond distance is 2.2840(8) A . The Namido-Fe-Npyridyi

angle is acute, viz. 61.90(7)°. The tmeda ligand binds to the Fe(II) center

chelating fashion with the N(3)-Fe(l)-N(4) angle of 81.03(9)�.

bite

in a

63

C16

C13

Figure 3-2 Molecular structure of [Fe{N(C6F5)(2-C5H3N-6-Me)}CI(tmeda)] (11)

Thermal ellipsoids are plotted at 30% probability level.

64

Table 3-5 Selected bond distances (A) and angles (。）for compound 11

Fe(l)-N(l) Fe(l)-N(3) Fe(l)-Cl(l) N(2)-C(l)

2.088(1) 2.197(2) 2.2840(8) 1.353(3)

F e � - N �

Fe(l)-N(4) N � - C �

N(1)-C(7)

2.242(1)

2.261(2)

1.351(3)

1.397(3)

N(l)-Fe(l)-N(2)

N(l)-Fe(l)-N(4)

N(2)-Fe(l)-N �

N(l)-Fe(l)-Cl( l ) N(3)-Fe(l)-Cl(l) C(l)-N(2)-Fe(l)

C(7)-N(l)-C �

61.90(7)

100.71(8)

160.38(8)

138.94(7)

110.37(7)

89.9(1)

119.2(1)

N(l)-Fe(l)-N(3)

N(2)-Fe(l)-N(3)

N(3)-Fe(l)-N(4)

N(2)-Fe(l)-Cl(l)

C(l)-N(l)-Fe(l)

C(7)-N(l)-Fe(l)

108.73(9)

95.54(7)

81.03(9)

102.03(5)

96.7(1)

143.7(1)

65

3.5.4 Reactivity Studies of [Fe(L^^^^)(Cl)(tmeda)] (11)

We have also investigated the reaction chemistry of complex 11. Our

approach was focused on the plausible substitution of the chloride ligand in

complex 11 by various anionic ligands, and chemical reduction of the complex by

alkali metals.

3.5.4.1 Ligand Substitution

1. Reactions with Lithium Amides

Attempts to replace the chloride ligand in complex 11 with other anionic

ligands such as NH2" and NMe�— have been unsuccessful. No reaction was

observed when complex 11 was reacted with LiNMe: under ambient conditions.

The reaction of complex 11 with LiNH: in thf under reflux for 8h yielded,

unexpectedly, the bis(amido) complex 8 (Scheme 3-5).

LiNH

thf, reflux, 8h

LiNMe

toluene, r.t.，8h

Scheme 3-5

No reaction

66

The mechanism for the formation of complex 8 in Scheme 3-5 is unclear at

this moment. Conceivably, the ligand may prefer forming a more stable

bis(amido) complex.

2. Reactions with Methyllithium and Other A Ikylating Reagents

Attempts to react [Fe(L"^^)Cl(tmeda)] (11) with LiMe yielded, again, the

bis(amido) [Fe(L^^^^)2(tmeda)] (8). Attempts to prepare other metal alkyl

complexes by reacting complex 11 with /er/-butyllithium or ethyl magnesium

bromide yielded unidentified products (Scheme 3-6).

LiMe

toluene r.t.. 8h

toluene r.t., 8h

EtMgBr

toluene r.t., 8h

Scheme 3-6

Unidentified products

67

3.5.4.2 Reduction with Alkali Metals

Attempts to prepare univalent iron complexes by reduction of complex 11

with sodium or potassium metal were unsuccessful. No reaction was observed

upon treatment of complex 11 with sodium metal in toluene. Only the starting

material, complex 11, was isolated after work-up of the reaction mixture. On the

other hand, treatment of complex 11 with potassium metal under identical reaction

conditions yielded only the bis(amido) complex 8 (Scheme 3-7).

Na

toluene, r.t., 8h

K

No reactio门

toluene, r.t., 8h

F F

Scheme 3-7

68

3.6 Synthesis of Fe(III) Tri(amido) Complex

Other than the iron(II) complexes 8 and 11, we are also interested in the

preparation of the corresponding Fe(III) derivative. Reaction of 3/2 equivalents

of the potassium amide 2 with FeCls in toluene afforded (12) in 40%

yield (Scheme 3-8).

n Z n 入 N I \

-CcFc

:N 3/2 equiv

:N K K

N:

N：

�6卜5 T I

FeClg toluene, r.t., 8h

Fe(LC6F5)3

12 40%

Scheme 3-8

Attempts to obtain good quality crystals of complex 12 for X-ray diffraction

studies were unsuccessful. Nevertheless, the formulation of complex 12 was

confirmed by elemental analysis. Melting point determination was recorded as

176—180° (dec). The solution magnetic moment of 5.98 ^B for complex 12, as

determined by the Evans method in toluene at 298 K, is consistent with a

high-spin Fe(III) center with a (f electronic configuration.

69

3.7 Experimentals for Chapter 3

Materials:

The metal chlorides MnCb, FeCb, NiCb (Strem), C0CI2 (Alfa Asear) and

FeCls (Aldrich) were used as received. Methyl lithium (ca. 1.6 M in diethyl ether)

and EtMgBr (ca. 3M in thf) were purchased from Acros. /^rZ-Butyllithium (ca.

1.67 M in pentane) was purchased from Aldrich. Sodium and potassium metal

(Riedel-de Haen) were washed with hexane before use.

Synthesis of Complexes:

General Procedures for the Preparation of (7-10)

In a typical experiment, a Schlenk tube was charged with MCI2 (ca. 2 mmol)

and toluene (15 ml). To a slurry of MCI2 in toluene at 0 was slowly added a

solution of [{K(LC6F5)(tmeda)}2] (2) (ca. 2 mmol) in the same solvent (20 ml).

The reaction mixture was stirred at room temperature for 24h. The reaction

mixture was filtered through Celite and concentrated to ca. 10 ml. Standing the

solution at room temperature afforded the desired metal(II) bis(amido) complex.

70

[Mn(LC6F5)2(tmeda)] (7). MnCls： 0.26 g, 2.07 mmol; [{K(L"^^)(tmeda)}2]:

1.71 g, 2.00 mmol. Yield: 0.43 g, 30%. M.p.: 254-256 X. jiidr = 5.96 lB.

Anal. Found: C, 50.73; H 3.76; N, 11.96 %. Calc. for CsoHzgNeFioMn: C, 50.22;

H, 3.93; N, 11.71%.

[Fe(LC6F5)2(tmeda)�（8). FeCb： 0.26 g, 2.05 mmol; [{K(L^^^^)(tmeda)}2]：

I.71 g, 2.00 mmol. Yield: 1.00 g, 70%. M.p.: 220-222 "C (dec). |ieff= 5.12

I B. Anal. Found: C, 50.01; H 3.86; N, 11.71 %. Calc. for CaoHjgNeFioFe: C,

50.16; H, 3.93; N, 11.69%.

[Co(LC6F5)2(tmeda)�（9). C0CI2： 0.26 g, 2.00 mmol; [{K(L^^^^)(tmeda)}2]:

1.71 g, 2.00 mmol. Yield: 0.57 g, 40%. M.p.: 207-209 leir = 4.28

Anal. Found: C, 49.82; H 3.93; N, 11.67 %. Calc. for CsoHzgNgFioCo: C, 49.94;

H, 3.91; N, 11.64%.

[Ni(LC6F5)2(tmedjO�（10). NiCb： 0.26 g, 2.00 mmol; [{K(L^^^^)(tmeda)}2]：

I.71 g, 2.00 mmol. Yield: 0.72 g, 50%. M.p.: 237—238�C (dec). |ieff = 2.82

|LIB. Anal. Found: C, 49.74; H 3.89; N, 11.63 %. Calc. for CaoHjgNeFioNi: C,

49.96; H，3.91;N, 11.65%.

[Fe(LC6F5)ci(tmeda)�（11). To a slurry o fFeCb (0.26 g, 2.05 mmol) in toluene

(10 mL) at OX added a solution of [{K(L^^^^)(tmeda)}2] (0.86 g, 1.00 mmol) in

the same solvent (10 mL). The reaction mixture was allowed to warm slowly to

room temperature, stirred for 8h, and then filtered. The solution was

concentrated under reduced pressure to ca. 8mL to afford the title compound as

yellowish green crystals. Yield: 0.48 g, 80%. M.p.: 176-180�C (dec). |Lieff =

71

4.94 i B. Anal. Found: C, 45.20; H 4.67; N, 11.75 %. Calc. for

Ci8H22N4F5ClFe: C, 44.98; H, 4.61; N, 11.65 %.

Fe(LC6Fs)3 (12). To a slurry ofFeCb (0.33 g, 2.03 mmol) in toluene (15 mL) at

0 was added a solution of [{K(L^^^^)(tmeda)}2] (2.6 g, 3.03 mmol) in the same

solvent (10 mL). The reaction mixture was allowed to warm slowly to room

temperature, stirred for 8h, and then filtered. The solution was concentrated to

ca. 8mL to afford the title compound as deep blue crystals. Yield: 0.71 g, 40%.

M.P.: 264-266�C (dec). fieff= 5.98 hb. Anal. Found: C, 49.32; H 1.94; N, 9.79

%. Calc. for Ci8H22N4F5ClFe: C, 49.39; H, 2.07; N, 9.68 %.

72

3.8 References for Chapter 3

1. (a) Lappert, M. R; Power, P. P.; Sanger, A. R.; Srivastava, R. C. Metal and

Metalloid Amides- Ellis-Horwood: Chichester, 1980, p.235-381, 465-544.

(b) Fryzuk, M. D.; Montgomery, C. D. Coord Chem. Rev. 1989, 95, 1-40.

2. Kempe, R. Angew. Chem. Int. Ed 2000, 39, 468-493.

3. (a) Fryzuk, M. D.; ManNeil, P. A. J. Am. Chem. Soc. 1981, JOS, 3592-3593.

(b) Fryzuk, M. D.; ManNeil, P. A.; Rettig, S. J.; Secco, A. S.; Trotter, J.

Organometallics 1982, 7, 918-930.

4. Mayer, J. M. Comments Inorg. Chem. 1988, 8, 125-135.

5. (a) Burger, H.; Wannagat, U. Monatsh. Chem. 1963, 94, 1007-1012.

(b) Burger, H.; Wannagat, U. Monatsh. Chem. 1964, 95, 1099-1102.

(c) Andersen, R. A.; Faegri, K.; Green, J. C.; Haaland, A.; Lappert, M. R;

Leung, W. P.; Rypdal, K. Inorg Chem. 1988, 27, 1782-1786.

(d) Murray, B. D.; Power, P. P. Inorg. Chem. 1984, 23, 4584-4588.

(e) Olmstead, M. M.; Power, P. P.; Shoner, S. C. Inorg. Chem. 1991, 30,

2547-2551.

6. (a) Barlett, R. A.; Power, P. P. J. Am. Chem. Soc. 1987, 109, 7563-7564.

(b) Chen, H.; Barlett, R. A.; Dias, H. V. R.; Olmstead, M. M.; Power, P. P.丄

Am. Chem. Soc. 1989 , 111, 4 3 3 8 - 4 3 4 5 .

7. (a) Bradley, D. C.; Fisher, K. J. J. Am. Chem. Soc. 1971, 93, 2058-2059.

(b) Bradley, D. C.; Hursthouse, M. B.; Smallwood, R. J.; Welch, A. J. J. Chem.

73

Soc., Chem. Commun. 1972, 872.

8. Deeken, S.; Proch, S.; Casini, E.; Braun, H. F.; Mechtler, C.; Marschner, C.;

Motz, G; Kempe, R. Inorg. Chem. 2006, 45, 1871-1879.

9. Kempe, R.; Noss, H.; Fuhrmann, H. Chem. Eur. J. 2001, 7, 1630-1636.

10. (a) Lee, H. K.; Lam, C. H.; Li, S. L.; Zhang, Z Y.; Mak, T. C. W. Inorg. Chem.

2001, 40, 4691-4695.

(b) Lam, C. H. M. Phil Thesis, The Chinese University of Hong Kong, 2002.

11. Lam, T. S. M. Phil Thesis, The Chinese University of Hong Kong, 2002.

12. Lee, H. K.; Peng, Yu; Kui, S. C. R; Zhang, Z. Y; Zhou, Z. Y; Mak, T. C. W.

Eur. J. Inorg. Chem. 2000, 2159-2162.

13. (a) VanderLende, D. D.; Abboud, K. A.; Boncella, J. M. Inorg. Chem. 1995，

34, 5319-5326.

(b) VanderLende, D. D.; Boncella, J. M.; Abboud, K. A. Acta Cryst. 1995’

C5I, 591-593.

74

CHAPTER 4 Summary of the Present Research

Work

The present research work was focused on the coordination chemistry of the

highly electron-withdrawing [N(C6F5)(2-C5H3N-6-Me)]~ (L^^^^) ligand towards

the transition metals.

The ligand precursor, [HN(C6F5)(2-C5H3N-6—Me)] (HLC6F5, i), ^^^ readily

prepared from 2-amino-6-picoline and hexafluorobenzene according to a

procedure similar to that of [HN(C6F5)(C6H5)] as described by Koppang and

CO—workers] The potassium derivatives [K(L^^^^)(tmeda)]2 (2) and

[K(LC6F5)(thf)2]2(3) were readily prepared from HLC6F5 ^ d kH, in the presence

and absence of tmeda, respectively (Scheme 4-1). The dimeric potassium amide

2 was used as a ligand-transfer reagent in our work.

KH, tmeda toluene, r.t.

rT^ I ^ 1) LiBu", tmeda, thf

N NH2 2) LiNHs.CgFe.thf.A ^

y I , � N >入 < N �

u X V CeFs'

thf\ X /thf th f .

^ X

X Shf

20%

Scheme 4-1

75

The reaction of ZrCU with 3/2 equivalents of 2 gave the tris(amido) complex

[Zr(LC6F5)3(a).(C7H8)] (4). X—Ray crystallography revealed that complex 4 is

mononuclear with the Zr(IV) center being bound by three A^,A/'-chelating

ligands and one terminal chloride ligand. The formulation of the complex was

also confirmed by NMR spectroscopy and elemental analysis. The reaction of

VCl3(thf)3 with 3/2 equivalents of 2 under the same reaction conditions afforded

the dark red crystalline (5). Unfortunately, attempts to obtain good

quality crystals of complex 5 for X-ray diffraction studies were unsuccessful.

Nevertheless, the result of elemental analysis was consistent with the empirical

formula of the complex. The Cr(III) derivative, (6)，was readily

prepared by treatment of CrCla with complex 2 in toluene at 40 X-Ray

crystallography revealed that complex 6 is mononuclear with the Cr(III) center

being bound by three A ’7V*-chelating ligands, forming a distorted octahedral

geometry (Scheme 4-2).

p k X I A 3/2 equiv ^ K K ^ J

r i x 丫

ZrCU

toluene, r.t., 8h

VCl3(thf)3 toluene, r.t., 8h

CrCIa toluene, 40°C, 8h

CTHD

\/(LC6F5)3

Scheme 4-2

76

Scheme 4-3

The reaction of FeCb with 0.5 molar equivalent of 2 led to the

mono substituted [Fe(L^^^^)Cl(tmeda)] (11). Attempts to prepare analogous

mono(amido) derivatives of Mn(II), Co(II) and Ni(II) were unsuccessful.

Attempts to react complex 11 with LiNH2, LiMe and potassium metal only led to

ligand rearrangement and the formation of the bis(amido) complex 8 (Scheme

4-4). These results suggest that the ligand has a high tendency to form

77

Treatment of anhydrous MCI2 (M = Mn, Fe, Co, Ni) with complex 2 in

toluene under ambient conditions yielded the corresponding bis(amido)

complexes [M(L^^^^)2(tmeda)] (M = Mn 7，Fe 8, Co 9，Ni 10) (Scheme 4—3).

X-Ray crystallography revealed that complexes 7-10 are isostmctural with the

metal center being bound by a pair of A^,A^-chelating ligands and one tmeda

molecule. The M-Npyridyi bond distances in complexes 7-9 are longer than the

corresponding M-Namido distances. On the other hand, the M-Npyndyi bond

distance in the Ni(II) analogue 10 is shorter than the corresponding M—Namido

distance. This observation suggests that the ligand in the Ni(II) complex

10 may behave as an aminopyridinato ligand with the anionic charge being

delocalized onto the pyridyl functionality.

MCI X K

XeFs

( 7 �

toluene

r . t , 8h

30% 70% 40% 50%

^ e

o i

M

c N

M

bis(amido) complexes with the late transition metal ions.

11

LiNH

thf, reflux, 8h

LiMe

toluene r.t., 8h

L . . 力 、 厂 尸

N F f , � F

K

toluene r.t., 8h

Scheme 4-4

Finally, the Fe(III) derivative, (12), was also successfully

synthesized in our work (Scheme 4-5). Although structural data of complex 12

could not be obtained at this stage of our work, results of elemental analysis are

consistent with the formulation of the complex.

|Z�

\

Z N 人 N'C6F5

3/2 equiv :N

CeFs

> K / N：

N丫 Ny^

FeCIs toluene, r.t., 8h

Fe 严 ) 3

12 40%

Scheme 4—5

1. Koppang, R. J. Organomet. Chem. 1972, 46, 193-200.

78

Table of Appendix

G E N E R A L P R O C E D U R E S , P H Y S I C A L M E A S U R E M E N T S A N D X - R A Y S T R U C T U R A L

A N A L Y S I S 8 0

IH N M R OFHLC6FS(1 ) 8 2

I^C N M R O F HLC6FS � 8 3

I9F N M R 0 F H L C 6 F S ( I ) 8 4

^H N M R O F [ K ( L C啦 ) ( T M E D A ) ] 2 (2) 8 5

" C N M R O F [K(LC6FS)(TMEDA)]2 (2)) 86

I 'F N M R O F [K(LC6FS)(TMEDA)H (2)) 8 7

IH N M R O F [K(LC6FS)(THF)2]2 (3) 8 8

" C N M R O F � K ( 严 ) ( T H F ) 2 ] 2 (3) 8 9

N M R O F [K(LC6FS)(THF)2H (3) 9 0

N M R O F ZR(L"^S)3(CL) . (C7H8)] (4) 9 1

13C N M R O F � Z R ( L C ® \ ( C L ) . ( C 7 H 8 ) 1 (4) 9 2

I9F N M R O F [ Z R ( L C ® \ C L ) . ( C 7 H 8 ) ] (4) 9 3

S E L E C T E D C R Y S T A L L O G R A P H I C D A T A O F C O M P L E X E S 2 A N D 3 9 4

S E L E C T E D C R Y S T A L L O G R A P H I C D A T A O F C O M P L E X E S 4 A N D 6 9 5

S E L E C T E D C R Y S T A L L O G R A P H I C D A T A O F C O M P L E X E S 7 A N D 8 9 6

S E L E C T E D C R Y S T A L L O G R A P H I C D A T A O F C O M P L E X E S 9 A N D 10 9 7

S E L E C T E D C R Y S T A L L O G R A P H I C D A T A O F C O M P L E X 11 9 8

79

General Procedures, Physical Measurements and X-Ray

Structural Analysis

All reactions were carried out under a purified nitrogen atmosphere using

Schlenk techniques. Solvents were dried over sodium wire and distilled under

nitrogen from sodium/potassium (hexane and toluene), sodium benzophenone

(diethyl ether and thf) and degassed twice by freeze-thaw cycle.

^H and ^ C NMR spectra were recorded on a Bruker DPX300 spectrometer at

300.13 MHz and 75.47 MHz, respectively. ^ F NMR spectra were recorded on a

Varian Inova 400 NMR spectrometer at 376.30 MHz. All spectra were recorded

in CDCI3 or C6D6 and the chemical shifts were referenced at 7.24 and 7.16 (^H

NMR), 77.16 and 128.06 ('^C NMR), respectively. ^ F NMR spectra were

referenced to the C6H5CF3 solvent at O.OOppm. Melting-points were recorded on

an Electrothermal melting-point apparatus and were uncorrected. Magnetic

moments were measured in toluene solutions at 298 K by the Evans NMR method

using a JEOL 60 MHz NMR spectrometer. Elemental analysis (C, H, N) were

performed by MED AC Ltd, Brunei University, UK.

Single-crystals of compounds 2-4, 6-11 suitable for crystallographic studies

were mounted in glass capillaries and sealed under nitrogen. Data were collected

on a Bruker SMART 1000 CCD diffractrometer using graphite—monochromatized

Mo-Ka radiation {X = 0.71073 A). The structures were solved by direct phase

determination using the computer programme SHELX-97 and refined by

full-matrix least squares with anisotropic thermal parameters for the

80

non-hydrogen atoms,

positions and included

temperature factors.

Hydrogen atoms were introduced in their idealized

in structure factor calculations with assigned isotropic

81

s o

5 T E

§

Z O Z

O t - g

_ §

^H

NM

R

Of

(1)

产N

入

X

TT

jtV

F F

00

K)

A

Current Ddta

NAME

EXPNO

PRDCNO

HL-

PULPROC

SOLVE

NT

NS •S

SWH

FIDHE

S AQ H6

•W

DE TE

•

1

MCREST

MCWRK

iBitinn Parameters

20070131

58

5 mm

BBO

======

==CHA

NNEL

f1 =

======

= NUCl

IH

PI

5.00 usee

PLl

-2.00 dB

SFOl

300.1312000 MHz

F2

-SI

SF 隱

LB

GB

PC

Processing

parameters MH

z

ID

NMR

plot paranfieters

CX

22.00

CY

12.00

FIP

8.500

F1

2551.10

F2P

0.000

F2

0.00

PPMCM

0.38536

HZCM

115.95932

Hz

Hz

ppni/c

Hz/cm

5 5 E . S - 0 0 0 0

2 I S . 0

l\ 5 1 7 2 6 d

> V.

g g T 6 - 0

S 卜 9 6 . 0

I e J C T 3 如 u i

，N

MR

o

f f

tj

OJ RU

^ C

N I

N

卜

CD

CD

R-^

—

RU

••

IN

— C

N O

D L

D

^ RN

RO

RN

^ CD

UD

CD

C

D

cn

iSD

c

n r^

in

cn

s . g 卜

o g r 卜 z

s s . 卜 卜

F N H

入 • N

^^

^J

l

18

0 1

60

14

0 1

20

BO

6

0 4

0

Parameters

HL-C

Acquisition

_ 20070303

11.09

"DOG

5 mm

NUCl

SFOl

CPDPflG2

NUC2

PL 12

SFD2

F2

SI

SF WDW

SSB

CHANNEL fl

========

13C

3.00

usee

-B.OQ

dB

75.4745111 MHz

CHANNEL f

2 ==

====

==

CX

CY

F2

PPMCM

HZCM

waltzlB IH

100.00 usee

120

OQ

dB

19

00

dB

.1315007 MHZ

75.4677390 MHz

EM

NMR

p]Qt

3 OQ 0

1 40

93,00 cm

B.21

cm

15093 55

-4.375

-330,20

Hz ppm

Hz

ppm/c

Hz/cir

S E E . S r

9 5 二 5 1 -

e

ca.

i=L

00

OJ

Pulse

Solvent:

Ambient

F1le:

YML_L2

INOVA-

S2p

u 1

chem. ciihk

75

•80

10

105

ppn

，9

f N

MR

o

f f

”

广N

八

F

a>

cn

CT5

a?

cn

CM

B S 2 ,

ar>

cc

UL

\

il

k W

Jv

NMR

of [K

(LC6

F5)(t咖

如)]2

(2)

卜 o

jcn 订

—o 卜

卜 C

Doo

i —

cvj

inr-^TT^^TruruoiTrmn

— —

o

—O

CD

OO

—

oo

oo

oo

o 卜

r^

卜

cn

UD

en

CD

Cir

NAME

EXPNQ

PRu'JNQ

KL (tireda) -H

F2

Acquisition

Parameters

20070703

Time

PR.'RHD

PU 二

WG

TD

SOLVTi-JT

NS •E

SViH

FISHE

S AQ DW

Ot

TF

• 1

MCHtST

MCWRK

5 mm

BBQ

NUCl

PI

PLl

SFOl

CHANNEL f1

===:

IH

5.00

-2.0

0 300.1312000

MHz

F2

SI

SF

GB

PC

Pro

cess

ing

pai^

amet

ers

MHz

ID

NMR

PLOT

PARAMETERS

CX

22

00

CY

50.00

FIP

0.

F1

2551,

F2P

F2

PPMCM

H2CM

An

人 N

'C6F

5 I

\/

Iz

N\ 入

/

N�

^K

K

�

NZ

y "

NC

I

A

\

V\

cn OD

―I

cn OJ

V

I O

OJ

O M

O

^

TN

CN

cn

J / s ^ . o ru

1 2 & 芸 I

rjMR plot

cx

CY

NM

R o

f�

K(

LC

6F

5)

(t

me

dJ

J2 (

2)

23.00 cm

50 .00

cm

185.000 ppm

13951.53 Hz

5.000 卩

pm

377.34 Hz

7 82609 pDm/cdi

)90

61694 Hz/cm

INST 隱

PRDBHD

PULPRDG

TO SOL

VENT

SWH

FIDRE5

AG

TE

•N 八

N'C

6F5

\/

\/

N:

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K�

z

V、

：

PC

.40

oo

OS

r P'

N

N^

MCRES

T MCW

RK

NUCl

PI SFOl

0.030

0QO

OD

0.

0000

0000

0

01500000

CHANNEL f1

========

13C

3.00

usee

-5.00

dS

75.4745113 MHz

CHANNEL

f2

300

waltzlB IH

100.00 usee

120.00 dB

19.00 d已

1315007 MHz

Deta

Param

eters

KL (tm

eda) -

C

lisition 2Q07Q722

12.17

5 mm

MM

yyyrv

A/

Jj

j u

J

iiiiiini

JiiiB

Htfii

iiiiiiiiii

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0 rrn

ymiim

rn

150

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60

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30

20

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S S . B S T

s o . §

s . g E T s r s — 1

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E

CL

C

L

c M

p M c

e e l s 附

付 o

e Q N

t 呢 w K

F2

Da1

Tim

STANDARD

IH

OBSERVE

，N

MR

o

f [K

(LC6

F5)(t

med

J�2

(2)

Pulse

s2pul

So

1vent:

Ambient

temperature

File:

YML^KLt

INOVA-^00

”inova400.chem.cuhk,

Pulse

.5

Acq

Width

100-0

kHz

128

repetitions

OBSERVE

F19,

376.3039260

MHz

DATA

PROCESSING

Line

broadening

1.5

Hz

FT

size

262144

Total

time

1 min,

53

sec

A ,八

:N

/ C6F5

Ar

C.F

N

N

\X

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K

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90

9

5

100

10

5

11

0

15

pp

m

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R

of

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s s . 工

g . s -

3 . g 」

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u o . z

0 9 二

cn C

5 i

n r

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in

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m r\

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—

in in

in m

m in

in

n m

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rn m

m

00

00

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K Z

thf

thf'

C.

IN LD CD M

R-- RU OJ

O

JLO

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CN

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CD

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C

OR

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M

C\J

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o

cn

cn

o

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nj

m

m

Cu-n^nt

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•at3_

Time

工

PRiiRHO

TD

SOLVPrtT

NS •S

SW-"

Finni

S DW

DE

TE

MCREST

MCWHK

20071014

15.25

5 nim

BBO

-IH

CDC13

NUCl

PI

PLl

SFDl

F2

-SI

SF

HOW

SSB

LB

GG

CX

CY

FIP

F1

F2P

F2

PPMCM

H2CM

CHANNEL f1

========

IH

5.00

usee

-2.00

dB

300.1312000 MHz

Processing

parameters

32768

MHZ

.1300308

EM 0

0.30 0

1.00

Hz

plot parameters

22.00 cm

10.00

cm

2701.17

-0.0

00

—0.

00

122.

HZ ppm

Hz

ppm/c

Hz/cn

广 i

MCBE3T

MCWRK

NUCl

PI

SFOl

CHAN

NEL f

l ==-=

13C

3

00

-6

.0

0

75.4745111

MHz

CP0PHG2

NUC2

PL12

SF02

CHANNEL

f2

====

waltzlB IH

lOO.00

120

OD

19

00

300.1315007

MHz

MHz

^D

NMR

plot

parameters

CX

23

00

CY

100

00

FIP

204.375

Fl

15423 75

Hz

_F2

PPMCM

HZCM

97

Hz

ppni/c

HZ/CT

NM

R

of

(3)

00 vo

180

140

120

80

60

40

20

E E e - S I -

B B 二 2 1

^L

nr

uL

nm

oo

cn

oc

n LD

•

ro "s—

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or

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7

—

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7 订

m

mr

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jc

Mc

u

0 6 E 9 g I .

u z . s 二

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NM

R

of

(3)

STANDARD

IH

S2

pu 1

Sol

vent:

Ambi

ent

temperature

=116：

YML

KLTHF

• c

hem.cuhk.

Pulse

40.9

degree

Acq.

time

0.875 s

Width

60015.0

Hz

128

repetitions

DBSERVE

F19

, 376 .

PROCESSING

! ii

C6F5

-85

-90

—,

T

, i

— -

T

r •

• r

——

I .

—•—

-9

5 -10

0

J�

1

05

110

11

5

ppm

s ^

CD m

m oj

in

un in

m

en cn

m

OD c

\j 卜

mm

in

rvi O

LD C

\J o

QO U

D U

D m

o

oo

r^r^

r^

卜、

inin

A J

_v

^H

NM

R

of

[Zr(

L^^'=

^)3(

CIH

CjH

8)]

(4)

IT?

— in

OJ —

O

oj

oj r

u

F N

^

OjU

8

U

1

Cu~"，

t NAME

EX—NO

PRuCNQ

Zr-

F2

- Acquisition

Time

INS I:細

Ppn

HO

PUi-r.qOG

5 mm

BBO

SOLVE

NT

NS •E

SWH

Fin

q;is

DW

Qb

TE

• 1

MLHbST

HCIf'nK

========CHANNEL

f1

========

隱1

IH

PI

5.00

usee

PLl

-2.00 dB

SFOl

300.1312000

MHz

F2

SI

SF

Processing

parameters

MHz

ID

NMR

plot

parameters

CX

22.00

CY

15.00

FIP

B.500

F1

2551.11

F2P

0.000

F2

0.00

PPMCM

HZCM

115

Hz

O O O C T B

( 8 s l e j f I , 卯

”c

NMR

of

[Zr(

LC6F

5)3(

ci)*

(C7H

8)�

(4)

—

CN

OC

DO

CD

M

IN

ML

O^

^R

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⑴”

OD"^

卜卜

O

OJ

MO

D

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DL

DC

DL

NM

LN

RN

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R•

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MU

D M

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——

CN

CN

I^

C^

DC

NA

DC

OC

OH

LN

RU

NI

M

LH

'^

'^

'Q

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CT

^M

MR

UO

JO

JN

JC

UN

JO

J^

O

—

—

—

I

— --L —

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一

a欢

CvHg

FIDRCS

AG

RG •W

•E

TE

•1 dll

MCRE5T

NUCl

PI

PL,

SFOl

-ID

NMR p

CX

CY

F1

^PM

CM

HZ CM

Current

NAME

EXPN'J

Tilntr

INF-

VIUM

pnf

:?HD

PU

L'iQ

G

TC

S01.,.= NT

I W

i

Parameters

Zn-080901

CHANNEL fl 13C

3 00

use:

-6.00 dB

75.4745111 MHz

CHANNEL f2

waltzie IH

100 00 usee

120.00 dB

19.00

dB

300.1315007 MHz

let

EM 0

3 00

0

1.40

23.00

30

00

Hz

15093 55

0.000

0,0

0

Hz

HZ

69565 ppm/cni

24109 Hz/con

iiiiiiiiiiii|iiiiiii.i.i.iuiniiiiiiiiitiriiii

llllllllllllllllllllll|II.I.I.IIMMIIIIIUIIIIII.Iil.lllllll|llll

14

0 丨""|111川|丄

uiiimmiii"im"‘"Miinmiji

120

100

1»丨,1",1"1丨"1|丨丨1""1_11""1""",1丨1丨1丨111"丨丨1丨1丨_丨,丨1""丨丨丨丨丨1"丨丨"丨_丨丨丨丨旧11旧丨1"||111

80

60

4

0

B Z 5 - S T -

e C3L

Q.

SO

to

，N

MR

of

[Zr(

LC網

)3(C履

).(C

tHs)

�(4

) STANDARD

IH

S2pu

1

novalOO.chem.cuhk.

Pulse

40.9

degr<

Acq.

time

0.875

Width

100.0

kHz

128

repetitions

OBSERVE

F19,

37i

DATA

PROCESSING

Line

broadening

FT

size

262144

Total

time

1 mi

n,

Hz

53

VO UJ

.1

F

\ zC

l

L %

Cy

Hg

U

10

10

20

•30

40

60

7 0

•80

90

JN 1

--10

110

IZO

ppm

Selected crystallographic data of complexes 9 and 10

Compound

Molecular formula C36H44N8F10K2 C40H44N4F10K2O4

Molecular weight 856.97 912.98

Crystal size, mm^ 0.50x0.40x0.30 0 .40x0.30x0.20

Crystal system monoclinic monoclinic

Space group Cllc P2i/n

a, A 19.939(2) 13.5275(14)

b，A 12.0041(12) 10.1730(10)

c ,A 17.7619(18) 16.5168(18)

P，deg

Z

v，A3

96.910(2) 4

99.105(2) 9

P，deg

Z

v，A3 4220.4(7) 22.443(4)

Density, g cm" 1.349 1.351

Abs. coeff., mm-i 0.305 0.295

Reflection collected 14181 14960

Independent reflections 5108 (Rint = 0.0526) 5426 (Rint = 0.0464)

Obs. Data wi th />2 o(/) 2081 2137

Final R indices [/>2o(/)] R1 = 0.0656

= 0.1674 RJ =0.0744

wR2 =0.2167

R indices (all data) RJ = 0.1698

wR2 = 0.2229 RI =0.1707

wR2 二0.2856

94

Selected crystallographic data of complexes 9 and 10

Compound

Molecular formula C43H26N6Fi5ClZr C36Hi8N6Fi5Cr

Molecular weight 1038.36 871.56

Crystal size, mm^ 0.40x0.30x0.20 0 .34x0.25x0.22

Crystal system monoclinic monoclinic

Space group CUc Pliln

a, A 30.973(4) .11.1051(5)

b’A 14.0278(14) 19.938(1)

c ,A 20.885(2) 16.1663(8)

P, deg

Z

v，A3

106.954(4)

8

92.996(1)

4

P, deg

Z

v，A3

o

8680.0(16) 3574.6(3)

Density, g cm" 1.589 1.619

Abs. coeff, mm-i 0.419 0.436

Reflection collected 29121 22002

Independent reflections 10481 (Rint = 0.0698) 8689 (Rint = 0.0196)

Obs. Data with/>2o(7) 5721 6301

Final R indices [/>2o(7)] 7 7 = 0.0571 慮=0.1414

R1 = 0.0507

= 0.1463

R indices (all data) RJ = 0.1233

wR2 = 0.1763 R1 = 0.0725

wR2 = Q.\661

95

Selected crystallographic data of complexes 9 and 10

Compound

Molecular formula CsoHigFioNeMn C3oH28FioN6Fe

Molecular weight 717.52 718.41

Crystal size, mm^ 0.40x0.40x0.30 0 .40x0.30x0.20

Crystal system monoclinic monoclinic

Space group C2/c C2/c

a, A 24.178(4) 24.171(3)

b ,A 8.0068(14) 7.9661(8)

c ,A 18.930(3) 18.8339(19)

P, deg

Z

v , A 3

119.609(3)

4

119.933(2)

Q

P, deg

Z

v , A 3 3186.0(10)

O

3142.7(6)

Density, g cm" 1.496 1.518

Abs. coeff., mm-i 0.504 0.571

Reflection collected 9073 8867

Independent reflections 3125 (Rint= 0.0440) 3082 (Rint = 0.0289)

Obs. Data wi th />2 o(/) 2380 2452

Final R indices [/ >2o(/)] RI = 0.0619 減2 = 0.1670

RJ = 0.0469

慮=0.1207

R indices (all data) R1 = 0.0808

= 0.1834 RJ = 0.06\5 慮=0.1323

96

Selected crystallographic data of complexes 9 and 10

Compound 9 10

Molecular formula C30H28F10N6C0 C3oH28FioN6Ni

Molecular weight 721.5 721.26

Crystal size, mm^ 0.40x0.30x0.30 0.40x0.30x0.20

Crystal system monoclinic monoclinic

Space group CUc CUc

a, A 24.163(3) 24.350(2)

b, A 7.9164(10) 7.9425(8)

c,A 18.748(2) 18.6483(18)

P，deg

Z

v,A3

119.786(2)

8

121.302(2) « P，deg

Z

v,A3

0

3112.4(7)

0

3081.6(5)

Density, g cm" 1.540 1.555

Abs. coeff., mm"' 0.643 0.722

Reflection collected 8739 8736

Independent reflections 3052 (Rint= 0.0364) 3033 (Rint = 0.0448)

Obs. Data with/>2a(/) 2375 2137

Final R indices [/>2o(/)] R1 = 0.0527

wR2 = 0.1294 R1 = 0.0540

wR2 = 0.\225

R indices (all data) R1 = 0.0703 慮=0.1 4 1 0

7 7 = 0.0859

= 0.1409

97

Selected crystallographic data of complexes 9 and 10

Compound 11

Molecular formula Ci8H22N4F5ClFe

Molecular weight 480.70

Crystal size, mm^ 0.40x0.30x0.20

Crystal system orthorhombic

Space group P2i2I2I

a, A 7.7277 (9)

b，A 16.031(2)

c，A 17.163(2)

(3, deg 90

Z 4

v ,A3 2126.2 (4)

Density, g cm'^ 1.502

Abs. coeff.，mm-i 0.889

Reflection collected 14429

Independent reflections 5138 (Rint= 0.0306)

Obs. Data with/>2o(7) 4180

RI = 0.0349 Final R indices [/>2o(7)]

RI = 0.0349 Final R indices [/>2o(7)]

= 0.0751

R indices (all data) RJ = 0.0489

R indices (all data) = 0.0810

98

CUHK Libraries

004561477