7456 Chem. Commun., 2012, 48, 7456–7458 This journal is c The Royal Society of Chemistry 2012

Cite this: Chem. Commun., 2012, 48, 7456–7458

Heterometallic thiacalix[4]arene-supported Na2NiII12LnIII

2 clusters with

vertex-fused tricubane cores (Ln = Dy and Tb)w

Kecai Xiong,ac

Xinyi Wang,bFeilong Jiang,

aYanli Gai,

acWentao Xu,

acKongzhao Su,

ac

Xingjun Li,ac

Daqiang Yuanaand Maochun Hong*

a

Received 1st April 2012, Accepted 15th May 2012

DOI: 10.1039/c2cc32360e

Two heterometallic thiacalix[4]arene-supported complexes

possess a trinary-cubane core composed of one [Ni2Ln2] cubane

unit and two [NaNi2Ln] cubane units sharing one LnIII

ion

(Ln = Dy and Tb). Only the DyIII

complex exhibits slow

magnetic relaxation behaviour of single molecule magnet nature.

The design and construction of transition-lanthanide (3d–4f)

heterometallic complexes has attracted considerable attention

in the past two decades because of their fascinating architectures1

and their potential applications as functional materials in

magnetism,2–4 luminescent materials,5 absorption materials6

and bimetal catalysts.7 As a result of the cooperativity between

the 3d–4f metal ions, significant magnetic behaviors have been

documented such as single molecule magnets (SMMs),2 single

chain magnets (SCMs)3 and magnetic refrigerants.4 However, the

preparation of designed heterometallic aggregates is still a formid-

able challenge owing to the variable and versatile coordination

behaviour of lanthanide ions and other factors. As is widely

known, the critical factor for the construction of heterometallic

3d–4f complexes is the rational choice of organic building block.

On the other hand, calix[4]arene derivatives and thiacalix[4]-

arene derivatives with functional groups and molecular back-

bones are most pivotal in the structural regulation of resultant

crystalline materials.8–10 In particular, thiacalix[4]arene deri-

vatives with four additional bridging sulfur atoms can bind to

up to four metal ions simultaneously forming metal4-

thiacalix[4]arene building blocks to support various polynuclear

clusters. To date, several homometallic thiacalix[4]arene-

supported complexes have been obtained.9,10 However, few 3d–4f

mixed-metal complexes involving (thia)calix[4]arenes have

been reported.8a–c,9a,b To the best of our knowledge,

MnIII4LnIII

4 are the largest 3d–4f aggregates sustained by

(thia)calix[4]arenes so far.8b For the reasons above and along

the line of our previous research on creating thiacalix[4]arene-

based complexes with interesting magnetic properties, we have

tried to expand the uses of carbonato anion in synthesizing

thiacalix[4]arene-supported 3d and/or 4f heterometallic

clusters employing sodium carbonate as a reactant. In the

present work, we have successfully obtained two new high nucle-

arity 3d–4f heterometallic clusters with vertex-fused tricubane

cores: [Na2NiII12LnIII

2(BTC4A)3(m7-CO3)3(m3-OH)4(m3-Cl)2-(OAc)6(dma)4]�2OAc�0.5dma�3MeCN�8DMA (Ln = Dy for

1, and Tb for 2; H4BTC4A = p-tert-butylthiacalix[4]arene;

dma= dimethylamine and DMA= N,N0-dimethylacetamide).

Herein the syntheses, structures and magnetic properties of

complexes 1 and 2 are presented.

X-Ray analysis reveals that both 1 and 2 crystallize in the

monoclinic system with space group P21/c.z The two

thiacalix[4]arene-supported clusters are isomorphous. Taking

complex 1 as representative, the structure possesses a hetero-

metallic Na2NiII12DyIII2 core capped by three BTC4A4� ligands

(Fig. 1). Within complex 1, both sodium ions are five-coordinated

in a distorted square-pyramidal geometry, while each NiII ion is

six-coordinated with distorted octahedral geometry. In addition,

Fig. 1 Molecular structure of complexes 1 (Ln=Dy) and 2 (Ln=Tb);

hydrogen atoms are omitted for clarity.

a State Key Laboratory of Structure Chemistry, Fujian Institute ofResearch on the Structure of Matter, Chinese Academy of Sciences,Fuzhou, 350002, China. E-mail: hmc@fjirsm.ac.cn;Fax: +86-591-83794946; Tel: +86-591-83714605

b State Key Laboratory of Coordination Chemistry, School ofChemistry and Chemical Engineering, Nanjing University, Nanjing,210093, China

c Graduate School of the Chinese Academy of Sciences, Beijing,100049, Chinaw Electronic supplementary information (ESI) available: Syntheses,crystallographic information, supplementary figures, PXRD of com-plexes 1 and 2. CCDC 874210 and 874211. For ESI and crystallo-graphic data in CIF or other electronic format see DOI: 10.1039/c2cc32360e

ChemComm Dynamic Article Links

www.rsc.org/chemcomm COMMUNICATION

Dow

nloa

ded

on 2

2 D

ecem

ber

2012

Publ

ishe

d on

22

June

201

2 on

http

://pu

bs.r

sc.o

rg |

doi:1

0.10

39/C

2CC

3236

0EView Article Online / Journal Homepage / Table of Contents for this issue

This journal is c The Royal Society of Chemistry 2012 Chem. Commun., 2012, 48, 7456–7458 7457

Dy1 and Dy2 are ten-coordinated with a distorted bicapped

square-antiprism geometry and eight-coordinated with a dis-

torted square-antiprism geometry, respectively. The two DyIII

centers are connected by two carbonato and one acetate

anions. Every four NiII ions simultaneously bond to the lower-

rim phenoxy oxygens and bridge sulfur atoms of one fully

deprotonated BTC4A4� ligand leading to a shuttlecock-like build-

ing block of NiII4-BTC4A, in which one carbonato anion acts as

the cork base. Three subunits are linked together in an up-to-up

fashion through four cations (two Na+ ions and two DyIII ions)

along with other anions (including two Cl� anions, four OH�

anions and three OAc� anions), leading to a pseudo-trigonal

planar entity with heterometallic Na2NiII12DyIII2 cluster. All

carbonato anions bind to seven metal centres with the same

chelating and bridging configurations, which can be represented

as [7.21233453567] according to Harris notation (Fig. 2a),11 different

from the reported [6.222]10b or [5.212234245]10c within the

thiacalix[4]arene-supported complexes. It is noteworthy that this

coordination mode has not been reported heretofore.

Further analysis shows that there is an unprecedented

trinary-cubane core composed of one [Ni2Dy2] cubane unit

and two [NaNi2Dy] cubane units, which share one DyIII ion at

the center of the Na2NiII12DyIII2 cluster (Fig. 2b and c). To the

best of our knowledge, the discrete cubane-like heterometallic

systems reported so far are restricted to a few 3d–4f systems.

This [NaNi2Dy] cubane core presents the first example which

consists of more than two metal elements. In addition, the

vertex-fused tricubane topology is a very rare structural type.

There is no previous example of such a discrete unit in

heterometallic chemistry, but two 3d–4f examples with tricubane

cores have been reported: three [Ce2Mn2] cubanes sharing a

trigonal-bipyramidal unit {Ce2(OH)3} in the centre12 or three

[Gd2Cu2] cubanes sharing three GdIII ions in a triangular way.13

The heterometallic cluster of 1 can be viewed as a tricubane

connects to six peripheral NiII ions through three m7-carbonatoanions (Fig. 2c). Three BTC4A4� ligands are located on the

trigonal plane of the tricubane core. Although there has been a

report with three calixarenes bonded to one CuII9 cluster, those

three p-tert-butylcalix[4]arene ligands lie on the trigonal plane.14

All the Ni–N, Ni–O, Ni–Cl, Ni-S, Na–N, Na–O, Na–Cl and

Dy–O bond distances are located in the normal bond length

range.1d,10b,15 The dma molecules were generated through the

decarbonylation of DMA.10b The Ni� � �Ni distances are

3.07–3.73 A, while the Ni� � �Dy distances are 3.46–3.69 A

within 1. Analysis of the bond lengths, charge balance and

bond valence sum calculations (BVS) suggests all Ni and Ln ions

of complexes 1 and 2 to be NiII and LnIII.16 Two CH3CN and

one DMA molecules penetrate slantwise into three

thiacalix[4]arene cavities stabilized by C–H� � �p interactions. In

addition, one acetate counter anion locates above the afore-

mentioned tricubane core via hydrogen bonds (Fig. S1w). Upon

crystal packing, complex 1 exhibits a bilayer structure in which

the pseudo-trigonal planar entities sit in an up–down fashion.

The interstices of the lattice are occupied by the solvent molecules

and acetate counter anions (Fig. S2w).The temperature dependent of magnetic susceptibilities

measured on the polycrystalline samples of 1 and 2 under

Hdc = 1000 Oe were displayed in Fig. 3a. At 300 K, the wmTvalues (40.53 and 36.48 cm3 K mol�1 for 1 and 2) are in

good agreement with the theoretical values of 40.34 and

35.64 cm3 K mol�1 for the two non-interacting LnIII ions

(Dy: 6H15/2, gJ = 4/3; Tb: 7F6, gJ = 3/2) and twelve NiII ions

(S= 1, g= 2).17 As the temperature is lowered, the wmT value

decreases continuously and falls rapidly in the lower tempera-

ture region, reaching 16.89 and 13.54 cm3 K mol�1 for 1 and 2

at 2 K, respectively. The Curie–Weiss fit of the data above

50 K give the Weiss constants y = �13.52 and �16.09 K for

complexes 1 and 2, respectively (Fig. 3a). The negative y valuesand the decrease of the wmT values at high temperature could

be ascribed to two sources, the antiferromagnetic interaction

between the spin carriers and the thermal depopulation of the

Stark levels of the DyIII and TbIII centers.

Upon increasing the applied external magnetic field, the

magnetizations of 1 and 2 increase to 15.7 and 16.0 Nb at

60 kOe, far below the saturation values of 44 and 42 Nb(Fig. S3w).17a No obvious hysteresis loop could be observed

for either complex at 2 K (Fig. S3w). In addition, temperature

dependent ac susceptibilities were measured under zero dc field

for 1 and 2; and slow relaxation of magnetization was

observed only in 1 (Fig. S4 and S5w). The frequency dependentac susceptibilities under zero dc field were also measured for 1

(Fig. S6w), from which the relaxation time at different temp-

eratures were evaluated. An estimation of the energy barrier

Ueff = 8.4 K and the pre-exponential factor t0 = 6.8 � 10�7 s

can be obtained from the Arrhenius fit of the t values (Fig. S6winset). Furthermore, Cole–Cole plots (Fig. S7w) have also been

obtained. The analyses of the plots according to the generalized

Debye functions give a values of 0.18–0.31 above 2.2 K,

indicating the presence of a relatively narrow width of the

Fig. 2 (a) Coordination modes of carbonato anions within 1 and 2

indicated by the Harris notation [7.21233453567]. (b) [NaNi2Ln] cubane

unit and [Ni2Ln2] cubane unit of 1 and 2. (c) The heterometallic

Na2NiII12LnIII

2 cluster possessing vertex-fused tricubane core and six

peripheral NiII ions connected through three m7-carbonato anions.

Fig. 3 (a) Temperature dependence of magnetic susceptibilities of 1 (Dy)

and 2 (Tb) in a 1000 Oe field. The solid lines are the best fitting to the

Curie–Weiss Law. (b) Temperature dependence of the in-phase (top) and

out-of phase (bottom) components of the ac magnetic susceptibility for

complex 1 in a static applied dc field of 2000 Oe and an ac field of 3 Oe.

Dow

nloa

ded

on 2

2 D

ecem

ber

2012

Publ

ishe

d on

22

June

201

2 on

http

://pu

bs.r

sc.o

rg |

doi:1

0.10

39/C

2CC

3236

0E

View Article Online

7458 Chem. Commun., 2012, 48, 7456–7458 This journal is c The Royal Society of Chemistry 2012

distribution of slow relaxation. However, the a value at 2 K

increases sharply to about 0.75, indicating the presence of

quantum tunnelling at lower temperature. The quantum

tunnelling could be partly suppressed by the application of

an external dc field, as can be seen from the shift of the peaks

of the ac signals toward higher temperatures measured under a

2000 Oe dc field (Fig. 3b). All these magnetic parameters

clearly evidence the SMM nature of this Dy-containing

complex 1. Given that 1 and 2 are isomorphous, it appears

that the necessary magnetic anisotropy is contributed by the

DyIII ions.17b One possible reason might be the fact that the

ground state of the Kramers ion DyIII is always degenerate

while this is not the case for TbIII ion.

In conclusion, two isomorphous heterometallic complexes 1

and 2 have been synthesized and structurally characterized. In

the presented structures, three shuttlecock-like NiII4-BTC4A

subunits are linked together in an up-to-up fashion through

two Na+ ions and two LnIII ions, along with other anions,

leading to a pseudo-trigonal planar entity. Within this entity,

there is a trinary-cubane core composed of one [Ni2Ln2] cubane

unit and two [NaNi2Ln] cubane units sharing one LnIII ion. It

should be noted that a cubane unit possessing more than two

metal elements has not been reported to date. Magnetic studies

reveal that only the DyIII complex shows the slow relaxation of

the magnetization expected for SMM behaviour. This work

shows that thiacalix[4]arenes can indeed lead to high-nuclearity

heterometallic clusters with intriguing structure and interesting

magnetic properties in the presence of ancillary anions. Our

efforts to prepare isotypic heterometallic complexes are ongoing.

We thank 973 Program (2011CBA00507, 2011CB932504),

National Natural Science Foundation of China (21131006,

20231020, 20971121, 21101093) and the Natural Science

Foundation of Fujian Province for funding this research.

The authors are grateful to Prof. Xiaoying Huang for assis-

tance with the crystallographic studies and Prof. Zhangzhen

He for valuable advice and discussions.

Notes and references

z Crystal data for complexes 1/2: C186H272.5N15.5O49Cl2S12Na2Ni12-Dy2/Tb2, M = 5040.73/5033.58, monoclinic, space group P21/c, a =21.546(2)/21.608(5), b = 30.412(3)/30.507(7), c = 36.028(4)/36.110(9) A,b = 99.774(2)/99.870(5)1, V = 23265(4)/23451(10) A3, Z = 4, Dc =1.439/1.437 g cm�3, F000 = 9496/9488, l = 0.71073 A, T = 120(2) K,2ymax = 52.0/52.01, 191383/183986 reflections collected, 45039/45032unique (Rint = 0.0420/0.0604). Final GooF = 1.076/1.077, R1 =0.0814/0.0938, wR2 = 0.2348/0.2446, R indices based on 41840/37462 reflections with I > 2s(I) (refinement on F2). The diffractiondata were treated by the ‘‘SQUEEZE’’ method as implemented inPLATON18 to remove diffuse electron density associated with thebadly disordered solvent molecules. This had the effect of dramaticallyimproving the agreement indices.

1 For example, see: (a) X. J. Kong, Y. P. Ren, W. X. Chen, L. S. Long,Z. Zheng, R. B. Huang and L. S. Zheng, Angew. Chem., Int. Ed.,2008, 47, 2398; (b) R. E. P. Winpenny,Chem. Soc. Rev., 1998, 27, 447;(c) C. Papatriantafyllopoulou, T. C. Stamatatos, C. G. Efthymiou,L. Cunha-Silva, F. A. Almeida Paz, S. P. Perlepes and G. Christou,Inorg. Chem., 2010, 49, 9743; (d) G. L. Zhuang, W. X. Chen,H. X. Zhao, X. J. Kong, L. S. Long, R. B. Huang andL. S. Zheng, Inorg. Chem., 2011, 50, 3843.

2 (a) C. Papatriantafyllopoulou, W. Wernsdorfer, K. A. Abboudand G. Christou, Inorg. Chem., 2011, 50, 421; (b) V. M. Mereacre,A. M. Ako, R. Clerac, W. Wernsdorfer, G. Filoti, J. Bartolome,C. E. Anson and A. K. Powell, J. Am. Chem. Soc., 2007, 129, 9248;

(c) Y. F. Zeng, G. C. Xu, X. Hu, Z. Chen, X. H. Bu, S. Gao andE. C. Sanudo, Inorg. Chem., 2010, 49, 9734.

3 D. Visinescu, A. M. Madalan, M. Andruh, C. Duhayon,J.-P. Sutter, L. Ungur, W. Van den Heuvel and L. F. Chibotaru,Chem.–Eur. J., 2009, 15, 11808.

4 (a) M. Manoli, A. Collins, S. Parsons, A. Candini, M. Evangelistiand E. K. Brechin, J. Am. Chem. Soc., 2008, 130, 11129;(b) G. Karotsis, M. Evangelisti, S. J. Dalgarno and E. K. Brechin,Angew. Chem., Int. Ed., 2009, 48, 9928; (c) Y. Z. Zheng,M. Evangelisti and R. E. P. Winpenny, Chem. Sci., 2011, 2, 99.

5 B. Zhao, X. Y. Chen, P. Cheng, D. Z. Liao, S. P. Yan andZ. H. Jiang, J. Am. Chem. Soc., 2004, 126, 15394.

6 C. J. Li, Z. j. Lin, M. X. Peng, J. D. Leng, M. M. Yang andM. L. Tong, Chem. Commun., 2008, 6348.

7 M. Shibasaki, S. Matsunaga and N. Kumagai, Synlett, 2008, 1583.8 For example, see: (a) S. Sanz, K. Ferreira, R. D. McIntosh,S. J. Dalgarno and E. K. Brechin, Chem. Commun., 2011,47, 9042; (b) G. Karotsis, S. Kennedy, S. J. Teat, C. M. Beavers,D. A. Fowler, J. J. Morales, M. Evangelisti, S. J. Dalgarno andE. K. Brechin, J. Am. Chem. Soc., 2010, 132, 12983; (c) G. Karotsis,M. Evangelisti, S. J. Dalgarno and E. K. Brechin, Angew. Chem.,Int. Ed., 2009, 48, 9928; (d) S. M. Taylor, R. D. McIntosh,C. M. Beavers, S. J. Teat, S. Piligkos, S. J. Dalgarno andE. K. Brechin, Chem. Commun., 2011, 47, 1440.

9 For example, see: (a) Y. F. Bi, Y. L. Li, W. P. Liao, H. J. Zhang andD. Q. Li, Inorg. Chem., 2008, 47, 9733; (b) Y. F. Bi, X. T. Wang,B. W. Wang, W. P. Liao, X. F. Wang, H. J. Zhang, S. Gao andD. Q. Li, Dalton Trans., 2009, 2250; (c) G. Mislin, E. Graf,M. W. Hosseini, A. Bilyk, A. K. Hall, J. M. Harrowfield,B. W. Skelton and A. H. White, Chem. Commun., 1999, 373;(d) A. Bilyk, J. W. Dunlop, R. O. Fuller, A. K. Hall, J. M.Harrowfield, M. W. Hosseini, G. A. Koutsantonis, I. W. Murray,B. W. Skelton, R. L. Stamps and A. H. White, Eur. J. Inorg. Chem.,2010, 2106; (e) A. Bilyk, J. W. Dunlop, R. O. Fuller, A. K. Hall,J. M. Harrowfield, M. W. Hosseini, G. A. Koutsantonis,I. W. Murray, B. W. Skelton, A. N. Sobolev, R. L. Stamps andA. H. White, Eur. J. Inorg. Chem., 2010, 2127; (f) T. Kajiwara,N. Kon, S. Yokozawa, T. Ito, N. Iki and S. Miyano, J. Am. Chem.Soc., 2002, 124, 11274; (g) N. Morohashi, F. Narumi, N. Iki,T. Hattori and S. Miyano, Chem. Rev., 2006, 106, 5291.

10 For example, see: (a) C. M. Liu, D. Q. Zhang, X. Hao andD. B. Zhu, Chem.–Eur. J., 2011, 17, 12285; (b) K. C. Xiong,F. L. Jiang, Y. L. Gai, Y. F. Zhou, D. Q. Yuan, K. Z. Su,X. Y. Wang and M. C. Hong, Inorg. Chem., 2012, 51, 3283;(c) K. C. Xiong, F. L. Jiang, Y. L. Gai, D. Q. Yuan, D. Han,J. Ma, S. Q. Zhang and M. C. Hong, Chem.–Eur. J., 2012,18, 5536; (d) K. C. Xiong, F. L. Jiang, Y. L. Gai, Z. Z. He,D. Q. Yuan, L. Chen, K. Z. Su and M. C. Hong, Cryst. GrowthDes., 2012, DOI: 10.1021/cg300483c; (e) K. C. Xiong, F. L. Jiang,Y. L. Gai, D. Q. Yuan, L. Chen, M. Y. Wu, K. Z. Su andM. C. Hong, Chem. Sci., 2012, DOI: 10.1039/c2sc20264f;(f) T. Kajiwara, N. Iki and M. Yamashita, Coord. Chem. Rev.,2007, 251, 1734; (g) A. Gehin, S. Ferlay, J. M. Harrowfield,D. Fenske, N. Kyritsakas and M. W. Hosseini, Inorg. Chem.,2012, 51, 5481.

11 R. A. Coxall, S. G. Harris, D. K. Henderson, S. Parsons,P. A. Tasker and R. E. P. Winpenny, J. Chem. Soc., Dalton Trans.,2000, 2349.

12 M. Wang, D. Q. Yuan, C. B. Ma, M. J. Yuan, M. Q. Hu, N. Li,H. Chen, C. N. Chen and Q. T. Liu, Dalton Trans., 2010, 39, 7276.

13 C. Aronica, G. Chastanet, G. Pilet, B. Le Guennic, V. Robert,W. Wernsdorfer and D. Luneau, Inorg. Chem., 2007, 46, 6108.

14 G. Karotsis, S. Kennedy, S. J. Dalgarno and E. K. Brechin, Chem.Commun., 2010, 46, 3884.

15 C. M. Anderson, A. Herman and F. D. Rochon, Polyhedron, 2007,26, 3661.

16 N. E. Brese andM. Okeeffe, Acta Crystallogr., Sect. B: Struct. Sci.,1991, 47, 192.

17 (a) M. Y. Li, Y. H. Lan, A. M. Ako, W.Wernsdorfer, C. E. Anson,G. Buth, A. K. Powell, Z. M. Wang and S. Gao, Inorg. Chem.,2010, 49, 11587; (b) M. Y. Li, A. M. Ako, Y. H. Lan,W. Wernsdorfer, G. Buth, C. E. Anson, A. K. Powell,Z. M. Wang and S. Gao, Dalton Trans., 2010, 39, 3375.

18 P. van der Sluis and A. L. Spek, Acta Crystallogr., Sect. A: Found.Crystallogr., 1990, 46, 194.

Dow

nloa

ded

on 2

2 D

ecem

ber

2012

Publ

ishe

d on

22

June

201

2 on

http

://pu

bs.r

sc.o

rg |

doi:1

0.10

39/C

2CC

3236

0E

View Article Online