O tlin Outline 2007/Lectures/Michel 0 Bangal… · 4. Magnetism of molecules assemblies without...
Transcript of O tlin Outline 2007/Lectures/Michel 0 Bangal… · 4. Magnetism of molecules assemblies without...
O tlin
ICMSICMS--ICMR Winterschool on Chemistry and Physics of Materials, Nov. 6ICMR Winterschool on Chemistry and Physics of Materials, Nov. 6--13, 2007, Bangalore13, 2007, Bangalore
1. IntroductionBrief history of molecular magnetism [1-6]
Outline
Brief history of molecular magnetism [ 6]2. Mononuclear species (complexes)2.1. Prequisites : free ion terms, states, orbitals and ligand field. Point Group Symmetry2.2. Metal-ligand interaction to tune electronic structure.2.3. Spin states, spin cross-over, devices [7]3. Magnetism of molecular assemblies in interaction. Polynuclear complexes
l h l l d l h3.1. Interaction between two electrons : phenomenological and orbital approaches3.2. Interaction Models [1]
Kahn ; comparison with Hoffmann (molecules)Comparison with Anderson, Goodenough-Kanamori (solids)
3.3. Case studies :Binuclear complexes [1 5]Binuclear complexes [1,5]Ferrimagnetic chains [1,5]Molecule-based magnets ; devices [8]
4. Magnetism of molecules assemblies without interaction :Single-molecule, single-chain magnets [9]Molecular, "bottom-up", approach of nanosystems, high spin molecules, p , pp y , g pThe "Mn12" and "Fe8" moleculesLocal anisotropy ; magnetic quantum tunneling effect.
5. ProspectsMultifunctional materials [10]Magnetism of a single molecule ; Information storage. Electronic quantum computingMagnetism of a single molecule ; Information storage. Electronic quantum computing
molecule-based magnets ? Why ?y
L d it
Specific propertiesLow densityTransparentNanosizedOften biocompatible and biodegradableVery flexible chemistryMild chemistry : Room T Room PMild chemistry : Room T, Room P, Solution Chemistry
Fragile Agingg gDiluted
Multifunctional materials
• Flexibility of molecular chemistryT bl St t d P tiTunable Structures and Properties
• Magnetic and optical propertiesMagnetic and optical propertiesColor, chirality, non linear optics
M ti d l t i l ti• Magnetic and electrical properties(Supra)Conducting magnetic materials
Conducting magnets See P. Day lecture Nº2
Coronado et al. Nature 2000
Multifunctional materials
• Interplay of Spin with Light
• Light reveals the spin (magnetisation) :
• Interplay of « Spin » with Light
Light reveals the spin (magnetisation) Photomagnetic Prussian Blues analoguesPhotomagnetic molecules
• The spin (magnetisation) transforms light :Magneto-opticsO i ll i MOptically active Magnets
Ph t tPhotomagnets
Transforming magnetism by light
J. Miró, Muro de Luna, Mural ceramics, UNESCO, Paris
Spin cross over
Photoexcitation … Jablonski Diagramme
Many things can happen after excitation …
EnergySinglet Spin = 0
Intersystem crossinggy
Triplet Spin = 1hνIntersystem crossing
hν ‘
hν ‘’
Singlet Spin = 0
Coordinate
Photomagnetism in coordination chemistry• LIESST Effect • LD-LISC Effect• LIESST Effect
Light-Induced Excited Spin State
HS
• LD LISC EffectLigand-Driven Light-Induced
Spin Change
HSHSHS HS
HSh
LShν
L
hν
D ti t l I Ch 1984 24 2174
LS
R t l I Ch 1994 33 2273
LS
hν
Decurtins et al. Inorg. Chem., 1984, 24, 2174.
NN322 nm
Roux et al. Inorg. Chem., 1994, 33, 2273.
FeII(BS) → FeII(HS)hν
T < 50 K260 nm
Trans-StpyFeII(BS)
Cis-StpyFeII(HS)T < 90 K
« L.I.E.S.S.T. » Effect
LightInducedExcitedSpin StateStateTrapping
J.
« L.I.E.S.S.T. » Effect , Interpretation
P. Gütlich et al. et al., Angewandte Chem., 1994
Photoexcitation …
ESpin = 0
Many things can happen after excitation …
Energy
Spin = 1
Intersystem crossing
Metastable state(s)
Spin = 1
M ( )
• LIESST EffectLi h I d d E i d S i SSpin 1
Spin = 0
Light-Induced Excited Spin State
• LD-LISC Effect
CoordinateLigand-Driven Light-Induced Spin Change
S.Decurtins, A. Hauser, P. Gutlich Inorg. Chem. 1984, 24, 2174C. Roux, J. Zarembovitch et al. Inorg. Chem. 1994, 33, 2273
Gymkhana campus Bangalore, December 8, 2007
1) Ph t ti1) Photomagnetism= Transforming magnetism by light
2) Magneto optics2) Magneto-optics= Transforming light by magnetism
3) Applications3) Applications= Writing and reading
magnetic information with lightmagnetic information with light
What about the 8 branches star?What about the 8 branches star?Octacyano Complex ?
PolynuclearComplexp
Interaction with lightOctacyanometalate Precursors Heptanuclear Complexes
WIVC II WIVNiII WIVM IIWIVCuII6
MoIVCuII6
WIVNiII6MoIVNiII6
Monoclinic P na = 24 89 Å; b = 14 39 Å; c = 30 11 Å
Monoclinic 22 03 Å b 28 39 Å 22 01 Å
Monoclinic C ca = 25 39 Å; b = 15 22 Å; c = 30 72 Å
WIVMnII6
MoIVMnII6
a = 24.89 Å; b = 14,39 Å; c = 30,11 Åa = g = 90°; b = 108.81°;
a = 22.03 Å; b = 28,39 Å; c = 22,01 Åa = g = 90°; b =99.48°;
a = 25.39 Å; b = 15,22 Å; c = 30,72 Åa = g = 90°; b = 111.45°;
V. Marvaud, J.M. Herrera, work in progress
MoCu6 : Photomagnetic high spin molecule
hν (=405 nm), 19 h 5 K 5,0
6 x S = 1/2
S = 364 % S = 3
After hν
After hv and T> 300 K
Before hν4,0
4,5
mol
-1.K
)
h
3,0
3,5
χT (c
m3 .m hν406 nm
0 50 100 150 200 250 300
2,5H = 20000 G
T (K)
Collaboration: C. Mathonière, ICMC Bordeaux
Photo-induced electron transferPhoto-induced electron transfer
MoIV CuIIhν MoV CuI
5
MoIVCuII MoVCuI CuII
+5 +5
Mo VCu 6 MoVCu 1Cu 5MoV, d1 , S=1/2
Ferro interaction …MoIV, d2 , S=0No exchangeNo exchange6 isolated S=1/2 S=3
10
12
MoCu6BT avant Ir
Evolution de MoCu6 avant Ir, apres Ir et apres relaxation
8
10 MoCu6BT, avant Ir
MoCu6BTI2, apres Ir
RT Apres relaxation
4
6
Abs
orba
nce
2
4
0
2510 2520 2530 2540 2550 2560
EnergieEnergie
From V. Marvaud, F, Villain, A. Bachschmidt, Elettra, Triesta
MoCu6 : Magnetization under Irradiation in a microSQUID
4
60.008 T/s
2
4
B
0
M/N
µ B
-4
-2 0.04 K0.5 K1 K2 K
0.04 K0.5 K1 K2 K
0 h 10 h
-6-1 -0 5 0 0 5 1
2 K4 K
2 K4 K
1 0.5 0 0.5 1µ0 H (T)
V. Marvaud and Wernsdorfer, Louis Néel Laboratory, Grenoble
Looking at ther Mo-Cu compounds (also W analogues)
Monoclinic P 21/ca = 10.514 Å; b = 14.584 Å; c = 22.182 Åα = γ = 90°; β = 96 18°; V= 3381 4 Å3
MoIVCu2-(tren)
Monoclinic P 21/aa = 14.790 Å; b = 15.901 Å; c = �18.395 Å
MoVCu (AF, S=0)
α = γ = 90 ; β = 96.18 ; V= 3381.4 Å3
MoVCu4
α = γ = 90°; β = 109.208°; V= 4085.2 Å3
Orthorhombic P bcma = 10.388 Å; b =22.000 Å; c = �30.172 Å
α = β = γ = 90°; V= 6895.4 Å3
NH2
N NH2
H2N
MoIVCu6-(TPA)
Monoclinica = 27.0�95 Å; b = 17.13�5 Å; c = 33.172 Å
α = γ = 90°; β = 66.42°; V= 14114 Å3
NH2 H2N
li i 21/
N
N N
N
MoIVCu6
Monoclinic P na = 24.89 Å; b = 14,39 Å; c = 30,11 Å
α = γ = 90°; β = 108.81°;
Monoclinic P 21/na = 14.292 Å; b = 24,554 Å; c = 15,017 Åα = γ = 90°; β = 108.78°; V=4989.6 Å3MoIVCu6-Cis
TPA
Work by V. Marvaud et al.
Theoretical Study (DFT)Theoretical Study (DFT)
Collaboration : J.Tercero, E. Ruiz, S. AlvarezBarcelona University
Molecular Orbitals [Mo(V)(CN) ]3- (DFT)[Mo(V)(CN)8]3 (DFT)
Mo Square Antiprism Mo DodecahedronMo Square Antiprismd z2
Mo Dodecahedrond x2 -y 2
Molecular Orbitals for a pair[Mo(V)(CN) ] CN Cu(II)[Mo(V)(CN)7]-CN-Cu(II)
Dinuclear MoCu square antiprism Dinuclear MoCu dodecahedron
3,00000
SAP CSM - (Photo)MagnetismAntiprism
2,50000 WIVCu2SAPR
Antiprism
2,000001MoIVCu6FM
MoVCuAF
1'WVCuAFMoIVCu6FM(Trifl)
1'MoIVCu6FM
WIVCu4FM
1WVCuAF
1,50000Est1
2MoIVCu6FM
CuWV5 FMMoVCuFM(cyc)
MoIVCu2(en)N3D
1 Mo Cu6FM
2'MoIVCu6FM
Photomagnetism
0 50000
1,00000
Est2 MoIVCu6(Tpa) Dodecahedron
0,00000
0,50000
Est3DD
MoIVCu2
MoIVCu2(cyc)N2D
MoIVCuAF(bipy)
Dodecahedron
,0,00000 0,50000 1,00000 1,50000 2,00000 2,50000 3,00000 DD
in Prussian blue analogues … (3D) g ( )
Photomagnetism
C III F II [(C II(HS)F III(BS)]*hν
CoIII-FeII ⇒ [(CoII(HS)FeIII(BS)]*diamagnetic pairs paramagnetic
3D ferrimagneticbelow TCbelow TC
Hashimoto et al., Science, 1996 ; Verdaguer, Science, 1996
Photomagnets Cobalt-Iron Prussian blue analogues
The properties are deeply modified by the insertion of alkali cations
Co4[FeIII(CN)6]8/3•nH2O Cs2CoIII10/3CoII
2/3[FeII(CN)6]10/3 Cs4CoIII4[FeII(CN)6
8
on /
10-3
em
u
No effect of light
on /1
0-3
emu
neti
zati
on 1
0-4 /e
mu
4
4
2.5
Very small effect of light
n /1
0-3
emu4
h
0
4
5 10 15 20 25
Mag
neti
zatio
Mag
netiz
atio
Temperature /K
Mag
n
248 12 16 20
0
2
8 12 16 20 24
1
Temperatu re /K
Mag
netiz
atio
n
0
2
8 12 16 20 24T t /K
hν
Temperature /K Temperature /KTemperature /K
Under pressure V. Ksenofontov P. Gütlich, A. Bleuzen et al. Phys. Rev. B, 2003, 68, 0244151-6A. Bleuzen et al. Angew. Chem. Int. Ed., 2004, 43, 3728.
Synthesis.[FeIII(CN)6]3- + [CoII(H2O)6]2+ + C+ (C+=K+, Rb+, Cs+)
increasing size of the cation C
Rb1.8Co4[Fe(CN)6]3.30 13H2O Cs3.7Co4[Fe(CN)6]3.7 9.2H2OK0.1Co4[Fe(CN)6]2.8 18.4H2O
increasing size of the cation C
K+ Rb+ Cs+
O
O
O
O
OO
O
O
Fe/Co 0.70 0.83 0.93
IIIN C-N
C-N O
O
O
O
O
O
O
O
N
Co ligand field
CoIII -FeII
rally induced CoIIN4O2
CoIIIN6
a = 10.04 ± 0.05 Å
a 10 36 ± 0 05 Å
Co
N
N N
NN
N
Co
N
N O
O
CoII-FeIIIstructurally ind
electron transfera = 10.36 ± 0.05 Å
∆ 0 3 ÅN
N
O ∆a = 0.3 Å
Formation of CoIII-FeII pairs …I ti f lk li tiInsertion of alkali cation …
1) + n C+
Fe(CN)6
2) + n/3 [Fe(CN)6]3-
O
OO
O
OO
OO
O
OO
O
Fe(CN)6Co
H2OC N
OO
O
O
O
O
Co(NC)4+n/2(OH2)2-n/2
C-N O
• Insertion of C+ increases the ligand field ∆Co of Co(II)g Co ( )
Cobalt(II) : Ligand Field, spin state, geometry and reactivity
H O OHOH2
NC CNCN
CN NCNC
H2OCo
H2O OH2
OH2OH2
NCCo
NC CN
CNCN
CNCo
CN NC
OH2OH2OH2 CN
E² ² t
OH2
²² oct oct² oct
Strong FieldIntermediate FieldWeak Field Strong FieldLow SpinS = 1/2
Very Reducing Short Co-C
Intermediate Field Spin Transition ?
S = 3/2 or 1/2Reducing
Weak FieldHigh SpinS = 3/2Long Co-O Very Reducing Short Co CReducingLong Co O
CN
Origin of the diamagnetic pairs in Co-Fe Prussian Blues
NC FeIIINC CN
CN
CN
C NC FeIINC CN
CN
CNCoII
CN N
OH2
CNCN
C
CNCoIII
CN N
OH
NC FeII
CNCN
C215 pm
195 pm2
OH2
CN OH2OH2
E eg*e * El fAntibonding ! g
t2gt2g
eg* Electron transferAntibonding !
2g2g
HS CoII LS FeIII LS CoIII LS FeII
Paramagnetic : 3/2, 1/2 Diamagnetic : 0, 0Paramagnetic 3/2, 1/2 Diamagnetic 0, 0Distance CoIINeighbours 215 pm Distance CoIINeighbours 195 pm
Photo-induced electron transfer L l t t d C
• Photo-induced electron transfer = important dilation of the network
Local structure around Co.p
Rb1.8Co4[Fe(CN)6]3.30 Cs3.7Co4[Fe(CN)6]3.7hν =
defects = strains relaxation easy dilation
dilation strong strains very small effect of light
Rb C• Excited pairs CoII-NC-FeIII - same electronic structure - same local structure
Rb2 Cs4
as CoII-NC-FeIII pairs in K0.1Co4[Fe(CN)6]2.8
Oxidation StateOxidation StateXANES at the Co K edge : 1s2 4p 1s1 4p1
[CoII(OH2)6]2+
orba
nce
/a.u
.
1
23
K+
Rb+
Cs+
CoII
CoIII ]
Abs
o
[CoIII(CN)6]3-
Cs
• K0.1CoII4[FeIII(CN)6]2.8 18.4H2O
7700 7720 7740 7760 7780 7800Energy /eV
• Rb1.8CoII0.7CoIII
3.30[FeII(CN)6]3.30 13H2O • Cs3.9CoIII
4[FeII(CN)6]3.9 9.2H2O
Photoinduced electron transfer …hν
Spin = 0Intersystem crossing
[Co(II)-Fe(III)]*Co(III)-Fe(II)hν
Spin = 1
Energy Intersystem crossing+ Electron transfer
Spin = 1 Metastable stateSpin 1
Spin = 0 Co Fe distance
Metastable state
Pair : Paramagnetic3D : FerrimagneticCo-Fe distance 3D : Ferrimagnetic
Co(III)-Fe(II)
Diamagnetic
[Co(II)-Fe(III)]*
ParamagneticDiamagnetic Paramagnetic
Towards devices … ?
Magneto-opticsg pHow magnetism transforms light …g g
1
Eff
et
0
0,005
0,01
0,015
2 he res
Faible flux lumineuxP = 0.7 mW /mm2Spot du�
laserMagneto-optics
Le composˇ est initialement faiblement paramagnˇ tique�Le syst me ne transite pas sous faible flux lumineux
Champ /Oe
-0,015
-0,01
-0,005
-8000 -6000 -4000-2000 0 2000 4000 6000 8000
2 heures
Echantillon Reading
Le syst¸ me ne transite pas sous faible flux lumineux
0,005
0,01
0,015
Fort flux lumineux0 / 2S t d �
2 Writing
-4000 -3000- 2000 -1000 0 1000 2000 3000 4000
Champ /Oe
Eff
et
-0,015
-0,01
-0,005
0
2 heuresP = 70 mW /mm2
Au même point de
l'échantillon
Spot du�laser
Echantillon
Example of a+ Reading
Le syst¸ me transite sous fort flux lumineux = ECRITURE
0,0153
Example of aphotomagneticerasable
d it blAu même point de
l'échantillon
Spot du�laser
Echantillon
Eff
et
-0,015
-0,01
-0,005
0
0,005
0,01Faible flux lumineux
2 heuresP = 0.7 mW /mm2
3and rewritablememory
ReadingEchantillon
Champ /Oe-4000 -3000- 2000 -1000 0 1000 2000 3000 4000
Le signal dichro•que est tr¸ s faible : une partie des paires excitˇes relaxent
LECTURE
Coll. J. Ferré, J.P. Jamet, LPS Orsay
g
Next step : going to nanosize
200 200 nm200 nm
x 23000 nanometricr anisati n
200 nm
nanoparticles organisationof particles
A. Bleuzen, LCI Orsay, private communication
Work in progress : Magnetization of a few nanoparticles of CoFe Prussian Blue analogues, microSQUID, 4 K, under irradiaction
14 K
g , Q , ,
0.5
4 K
A50
00 min
M/M
s
irradiation with white light
-0.5
0 min1 min5 min20 min30 min70 min100 min3 h
-1-1 -0.5 0 0.5 1
3 h4 h12 h
µ0 H (T)µ0 ( )
(A. Bleuzen, W. Werndorfer)
Chi l M tChiral Magnets
Optically Active Magnets : Why ?
θθn
εn-θn
M
M
θm
εm-θm
-εnCotton Effect Faraday Effect
M-εm
Cotton : breaking of space symmetryFaraday : breaking of time symmetry
Formal Similarity of Faraday and Cotton Effects
MichaelMichaelMichaelMichaelFaradayFaraday ……FaradayFaraday ……1791-1867Fullerian Professor of Chemistry1833-1867
andand…… and and AiméAiméAiméAimé
CottonCotton
1869 - 1951French PhysicistOptical Physics
Circular dichroïsmCircular dichroïsm
What is new with Optically Active Magnets ?
Breaking of space and time symmetry
Cross-effect MagnetoCHiral Dichroism (MChD)
Unpolarised light
k Id+
≠
contributionγd(ω)k.M
to theUnpolarised light
k Id-
≠
dielectric tensor
L.D. Barron, J. Vrbancich, Mol. Phys. 51 (1984) 715
Magnetochiral Dichroism (MChD) :
µ(k,M,ω) = αd,l(ω)k + β(ω)M + γd,l(ω)k.M
CottonChi lit
FaradayM ti ti
Cross-Term2 d dChirality Magnetisation 2nd order(MChD)
k light wave vectorM magnetisation
Cf Barron, Rikken ...
Oxalate ligand1. Bis-Chelating
2 Stable (and inert) precursors complexes2. Stable (and inert) precursors complexes
3. Complexes as ligands
O
O
M'O
O
OM
O O
O
OO
O
O
M'O
MO O
O
OO
O
O
O
O
O
1 O OO
O
OO
M' 3
OO
O 21
Chiral complex
STRUCTURES OF 2D and 3D NETWORKS
Λ∆
ΛOO
MM1
L. Atovmyan et al, JETP Lett. 1993, 58, 766
2D∆∆
ΛOO
M2M1
∆ − Λ
Heterochiral Honeycomb Plane 2D Materials∆-Λ
Heterochiral Honeycomb Plane 2D Materials
ΛΛΛ
Λ ΛΛ
S. Decurtins et al, Inorg. Chem.1993, 32, 1888
3DO
O
O
O
M2M1
Λ − Λ or ∆ − ∆
Λ ΛΛ
ΛΛ 3D
Λ-Λ ou ∆-∆Λ Λ or ∆ ∆Homochiral Helix Structure 3D Materials
Interconnected helices
Λ-Λ ou ∆-∆
Fabrice Pointillart, Ph.D ThesisFabrice Pointillart, Ph.D Thesis
A very useful cation for chiral design
∆-[RuII(bpy)2(ppy)]+
• dimension• D3 Symmetry• Charge : +1g
ll lé
Cf Clément et al., Monatsh. Chem. 497 (2002), 117
Gruselle, Malézieux, Brissard …
BUILDING the 3D NETWORKS. Decurtins et al, Inorg. Chem. 1993, 32, 1888 R. Andrès et al, Inorg. Chem. 1999, 38, 4637 , g , ,
R. Andrès et al. Inorg. Chem. 2001, 40, 4633
The anionic subnetwork WRAPS around the assembling cation [Ru(bpy)3]2+
Helix PHelix M
STRUCTURES of 3D NETWORKSeHelix M
(P)(M)
Anionic Subnetwork Cationic Subnetwork[M(L)3]n+
- Cation Symmetry D3
Charge and
[MaMb(ox)3]n-
- Charge and size ad hoc
INDUCING CHIRALITY
Ru – N : 2,063(5) Å
{[RuΛ(bpy)3][Mn2Λ(ox)3]}n
Groupe d’espace : P4132
Mn – O1 : 2,135(5) Å
Mn – O2 : 2,169(5) Å
a = 15,508(1) Å
α = β = γ = 90°
{[Ru∆(bpy)3][Mn2∆(ox)3]}n
Groupe d’espace : P4332
a = 15,492(2) Å
Ru – N : 2,059(4) Å
Mn – O1 : 2,167(5) Å
α = β = γ = 90° Mn – O2 : 2,133(5) Å
The assembling chiral cation [Ru(bpy)3]2+ induces chirality on all the metallic centres of the anionic subnetwork
[Ru(bpy)2 (ppy)][MnCr(ox)3][ ( py)2 (ppy)][ ( )3]
They are chiralThrough resolved precursor [∆ or Λ MIII(ox)3]3-
NBu4[MnΛCr∆(ox)3]NBu4[MnΛCr∆(ox)3]
300
350
100
150
200
250
ΛCottonEffect
-100
-50
0
50
300 350 400 450 500 550 600 650 700
Effect
300
-250
-200
-150
-100
∆
-350
-300
Wavelength / nm
2D or 3D : Magnets below 10-20Kg
2 5
3.0
3.5
50
60
70
cm-3
1 5
2.0
2.52D-{MnCr}
20
30
40
M /
µ B
χ−1 /
mol
.c[Ru(bpy)3][ClO4][MnCr(ox)3][R (b ) ( )][M C ( ) ]
0 5
1.0
1.5
0 50 100 150 200 250 3000
10
T / K
M [Ru(bpy)2(ppy)][MnCr(ox)3][Ru(bpy)2(ppy)][NiCr(ox)3]
0 2 4 6 8 10 12 14 16 18 20
0.0
0.52D-{NiCr}
T / K0 2 4 6 8 10 12 14 16 18 20
TBAC NiO T 4 4K (l 580 )
Evidence of the MChD unpublished …3000 250
TBACrNiOx T= 4.4K (l=580 nm)
Phase Delta / °
Phase Lambda / ° ∆
2000
2500
200M Delta / ua
M Lambda / ua
Phase Lambda / °
Phase°a gr
ee
∆
1500150
sign
al d
elta
/ua P
hase delta
≈ 180°
nal /
ua
se /
deg
500
1000100M
s/ °
Sign
Pha
Λ
00
0
0
50
-500 0-100 0 100 200 300 400 500 600 700
H / mVC. Train, Coll. G. RikkenDFG MM SPP
Noyori museum, nagoya
On the way to transparent single crystals(work in progress)(work in progress)
R. Gheorghe, M. Gruselle, C. Train
1. (NH4)3[Cr(C2O4)3] + Mn(NO3)2+ ... 2. (NH4)3[Cr(C2O4)3] + Mn(NO3)2+ …
HCH3
CH3
+
H CH3CH3
+S+ R-N+ CH3
CH3
CH3
I- N+
CH3
CH3
CH3
I-S+ R-
NMePr2(S+)-secBuI NMePr2(R-)-secBuI
[NMePr2(S+)-secBu]3[Mn-∆-Cr(C2O4)3] [NMePr2(R-)-secBu]3[Mn-Λ-Cr(C2O4)3]
R. Gheorghe, M. Gruselle, C. Train
Structure of one of the enantiomers
Along a axis
Pl bHexagonalP 63 (no 173)Plane ab P 63 (no. 173)a = 9.4160 Åc = 16.8430 ÅVolume = 1293.11 Å3