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Volume 70 
Part 2 
Pages 169-172  
February 2014  

Received 5 October 2013
Accepted 19 December 2013
Online 9 January 2014

Two novel tri­methyl­sulfonium salts with polymeric {[SbCl4]-}n or {[CdCl3]-}n anions

aOrdered Matter Science Research Centre, College of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, People's Republic of China
Correspondence e-mail: jgsdxlml@163.com

The title organic-inorganic hybrid salts poly[tri­methyl­sul­fon­ium [[di­chlorido­anti­mony(III)]-di-[mu]-chlorido]], {(C3H9S)[SbCl4]}n, (I), and catena-poly[tri­methyl­sulfonium [cadmium(II)-tri-[mu]-chlorido]], {(C3H9S)[CdCl3]}n, (II), consist of tri­methyl­sul­fon­ium cations and polymeric {[SbCl4]-}n or {[CdCl3]-}n anions. The central metal atoms are coordinated by six Cl atoms, forming an anionic {[SbCl4]-}n three-dimensional framework (two of the four bridging chloride anions are located on two different centres of inversion) or anionic {[CdCl3]-}n one-dimensional chains. The tri­methyl­sulfonium cation of (II) is disordered over two sets of sites in a 0.791 (4):0.209 (4) ratio. All the anions are linked by tri­methyl­sulfonium cations through weak C-H...Cl hydrogen bonds to form three-dimensional structures.

1. Introduction

Recently, much attention has been concentrated on studies of new dielectric and ferroelectric materials, due to the discovery of dielectric-ferroelectric systems and their wide range of applications, for instance, as filters, capacitors, resonators or solid-state transducer components in microwave communication systems (Fu et al., 2008[Fu, D.-W., Zhang, W. & Xiong, R.-G. (2008). Dalton Trans. pp. 3946-3948.]; Vanderah, 2002[Vanderah, T. A. (2002). Nature, 298, 1182-1184.]; Ye et al., 2009[Ye, H.-Y., Fu, D.-W., Zhang, Y., Zhang, W., Xiong, R.-G. & Huang, S.-D. (2009). J. Am. Chem. Soc. 131, 42-43.]; Zhang et al., 2010[Zhang, W., Cai, Y., Xiong, R.-G., Yoshikawa, H. & Awaga, K. (2010). Angew. Chem. Int. Ed. 122, 6758-6760.]; Zhang & Xiong, 2012[Zhang, W. & Xiong, R.-G. (2012). Chem. Rev. 112, 1163-1195.]). In the search for potential ferroelectric materials, mol­ecular-based chlorido­antimonate(III) or chlorido­cadmate(II) organic-inorganic compounds have been of inter­est, as they often display solid-solid phase transitions induced by a variation in temperature (Walther et al., 1978[Walther, U., Brinkmann, D., Chapuis, G. & Arend, H. (1978). Solid State Commun. 27, 901-905.]; Piecha et al., 2012[Piecha, A., Bialonska, A. & Jakubas, R. (2012). J. Mater. Chem. 22, 333-336.]; Chaabouni et al., 2003[Chaabouni, S., Hadrich, A., Romain, F. & Salah, A. B. (2003). Solid State Sci. 5, 1041-1046.]; Zaleski, 1997[Zaleski, J. (1997). Ferroelectrics, 192, 71-79.]; Bujak & Zaleski, 2004[Bujak, M. & Zaleski, J. (2004). J. Solid State Chem. 177, 3202-3211.]; Ma et al., 2006[Ma, K., Xu, J., Zhang, P., Wang, Y., Wang, L., Fan, Y. & Song, T.-Y. (2006). Solid State Sci. 8, 1473-1476.]; Peral et al., 2000[Peral, I., Madariaga, G., Pérez-Etxebarria, A. & Breczewski, T. (2000). Acta Cryst. B56, 215-225.]; Kind et al., 1979[Kind, R., Plesko, S. & Arend, H. (1979). J. Chem. Phys. 71, 2118-2130.]). In previously reported ferroelectric metal-organic frameworks, compounds having the formulae A[SbX4] or A[CdX3] (A = organic cation and X = halide) often exhibit phase transitions, such as the structures of (4-NH2PyH)[SbCl4] and [(CH3)4N][CdBr3] (4-NH2PyH is 4-amino­pyridinium; Zhang & Xiong, 2012[Zhang, W. & Xiong, R.-G. (2012). Chem. Rev. 112, 1163-1195.]). In addition, chlorido­antimonates and chlorido­cadmates show a wide variety of stereochemical complexity because of both the variability of the metal-ion coordination geometry and the bridging capability of the halide anions. Knowing that the structures of {[CH3C6H4NH(CH3)2][SbCl4]}n and {(C3H10N)[CdCl3]}n, which contain polymeric anions, undergo solid-solid phase transitions (Walther et al., 1978[Walther, U., Brinkmann, D., Chapuis, G. & Arend, H. (1978). Solid State Commun. 27, 901-905.]; Chaabouni et al., 2003[Chaabouni, S., Hadrich, A., Romain, F. & Salah, A. B. (2003). Solid State Sci. 5, 1041-1046.]), we expected to obtain their tri­methyl­sulfonium analogues which would possibly have solid-solid phase transitions. With this in mind, two new organic-inorganic hybrid complexes {(C3H9S)[SbCl4]}n, (I)[link], and {(C3H9S)[CdCl3]}n, (II)[link], were pre­pared and characterized.

[Scheme 1]
[Figure 1]
Figure 1
The one-dimensional polymeric zigzag chain of (I)[link] with the SbCl3 pyramids (shaded), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes: (i) x - [{1\over 2}], y + [{1\over 2}], z; (ii) -x, -y + 1, -z + 2; (iii) -x + [{1\over 2}], -y + [{1\over 2}], -z + 2; (iv) x + [{1\over 2}], y - [{1\over 2}], z; (v) -x, y, -z + [{3\over 2}]; (vi) x, -y + 1, z + [{1\over 2}]; (vii) x + [{1\over 2}], -y + [{1\over 2}], z + [{1\over 2}].]
[Figure 2]
Figure 2
A packing diagram for (I)[link], viewed along the b axis, with weak C-H...Cl hydrogen-bond inter­actions shown as dashed lines.
[Figure 3]
Figure 3
The one-dimensional {[Cd([mu]-Cl)3]-}n chain in (II)[link], showing the atom-numbering scheme and the disordered cation. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes: (i) x + [{1\over 2}], -y + [{3\over 2}], -z + 1; (ii) x - [{1\over 2}], -y + [{3\over 2}], -z + 1.]
[Figure 4]
Figure 4
A packing diagram for (II)[link], with weak C-H...Cl hydrogen-bond inter­actions shown as dashed lines.

2. Experimental

2.1. Synthesis and crystallization

Mixtures of tri­methyl­sulfonium iodide (1.02 g, 5 mmol) and silver carbonate (0.69 g, 2.5 mmol) were added to water (30 ml) and stirred for 30 min at room temperature. The mixtures were then filtered and hydro­chloric acid (0.97 g, 5 mmol, 37% solution in water) was added to the filtrates with stirring over a period of 2 min. SbCl3 (1.14 g, 5 mmol) or CdCl2·2.5H2O (1.14 g, 5 mmol) were added to the above solutions to afford a colourless solution in each case. These solutions were left to evaporate at room temperature in air for two weeks and yielded colourless crystals of (I)[link] and (II)[link] suitable for single-crystal X-ray diffraction.

2.2. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1[link]. For both compounds, C-bound H atoms were included in calculated positions and refined using a riding model, with C-H = 0.97 Å and Uiso(H) = 1.5Ueq(C). The tri­methyl­sulfonium cation in (II)[link] was modelled as disordered over two sites, with a site-occupancy ratio of 0.791 (4):0.209 (4). All S-C and C...C distances in the disordered cation were restrained to be similar. The atomic displacement parameters of all atoms of this cation were also restrained to be similar.

3. Results and discussion

The asymmetric unit of (I)[link] consists of a trimethylsulfonium cation and an [SbCl4]- unit of a polymeric anion, with three Cl atoms in general positions and two bridging Cl atoms (Cl4 and Cl5) located on two different centres of inversion. As shown in Fig. 1[link], there are SbCl3 pyramids (Sb1, Cl1, Cl2 and Cl3) in the structure, with Sb-Cl bond lengths ranging from 2.3754 (9) to 2.4931 (9) Å. The average Cl-Sb-Cl angle for these atoms is 90.82 (3)°. Atoms Cl4 and Cl5 form symmetrical Sb-Cl-Sb bridges with considerably longer Sb-Cl distances [3.0325 (6) and 2.9024 (7) Å, respectively] between the SbCl3 subunits. These bridges result in extended zigzag anionic chains. Additionally, atom Cl3 has a short, probably bonding, contact with another Sb centre [3.4542 (13) Å]. Each Sb atom therefore accepts three long Sb-Cl contacts, although these are still much shorter than the sum of the van der Waals radii of Sb and Cl (4.0 Å; Pauling, 1960[Pauling, L. (1960). The Nature of the Chemical Bond, p. 260. Ithaca: Cornell University Press.]). The six Cl atoms bonded to each Sb atom form a distorted octahedron, with the short and long bonds in trans positions. As a consequence, the SbCl3 subunit is considerably deformed compared with gaseous SbCl3 (Konaka & Kimura, 1973[Konaka, S. & Kimura, M. (1973). Bull. Chem. Soc. Jpn, 46, 404-407.]), which has an Sb---Cl bond length of 2.333 (3) Å and a bond angle of 97.2 (9)°.

A coordination very similar to that in (I)[link] is found in the crystal structure of [NH(CH3)3]3[Sb2Cl9] (Kallel & Bats, 1985[Kallel, A. & Bats, J. W. (1985). Acta Cryst. C41, 1022-1024.]). In the crystal structure of SbCl3, on the other hand, no coordinative Sb...Cl contacts are shorter than 3.457 (1) Å; thus, an almost undistorted SbCl3 mol­ecule is observed, with bond lengths between 2.340 (2) and 2.368 (1) Å (Lipka, 1979[Lipka, A. (1979). Acta Cryst. B35, 3020-3022.]). Almost undistorted SbCl3 subunits are also observed in many other SbCl3 adducts (Demaldé et al., 1972[Demaldé, A., Mangia, A., Nardelli, M., Pelizzi, G. & Tani, M. E. V. (1972). Acta Cryst. B28, 147-150.]; Lipka & Mootz, 1978[Lipka, A. & Mootz, D. (1978). Z. Anorg. Allg. Chem. 440, 217-236.]).

The Sb-Cl distances of (I)[link] are very different, unlike those in Cd complexes such as the structure reported by Corradi et al. (1997[Corradi, A. B., Cramarossa, M. R. & Saradini, M. (1997). Inorg. Chim. Acta, 257, 19-26.]), and this may be induced by the difference in valence electron count. The Cl-Sb-Cl angles are in the ranges 80.54 (2)-106.987 (15) and 166.250 (19)-169.30 (3)°, deviating slightly from ideal octa­hedral angle values (90 and 180°). The Sb atoms are bridged by atoms Cl4 and Cl5, giving rise to infinite polymeric chains extending in the [110] and [[\overline{1}]10] directions, with an Sb1ii...Sb1...Sb1iii angle of 103.65 (3)° (symmetry codes as in Fig. 1[link]), indicating that the polymeric chain is zigzag (Fig. 1[link]). The Sb...Sb distances in these chains are 6.0648 (13) and 5.8046 (15) Å, which are much longer than those found in the previously reported structures (C5H14n3)[SbCl4] and (C2H5N)4[Sb4Cl16] (Bujak et al., 1999[Bujak, M., Osadczuk, P. & Zaleski, J. (1999). Acta Cryst. C55, 1443-1447.]; Zaleski, 1997[Zaleski, J. (1997). Ferroelectrics, 192, 71-79.]), but comparable with those found in (C3n5n2)4(Sb2Cl10) and [BeCl(12-crown-4)][SbCl4] (Neu­muller & Dehnicke, 2006[Neumuller, B. & Dehnicke, K. (2006). Z. Anorg. Allg. Chem. 632, 1681-1686.]; Piecha et al., 2012[Piecha, A., Bialonska, A. & Jakubas, R. (2012). J. Mater. Chem. 22, 333-336.]). The nearest two perpendicularly oriented chains are linked to each other by long Sb1-Cl3v contacts in the [001] direction, forming Sb2Cl2 loops with an Sb...Sb distance of 4.5725 (12) Å, which results in a three-dimensional framework (symmetry codes as in Fig. 1[link]). The tri­methyl­sulfonium cations are located in the inter-framework space and the charges of the cations are balanced by the anionic {[SbCl4]-}n polymer framework.

The bond lengths and angles of the tri­methyl­sulfonium cations of (I)[link] are in agreement with those reported in the literature (Hess et al., 2007[Hess, D., Gorlov, M., Fischer, A. & Kloo, L. (2007). Z. Anorg. Allg. Chem. 633, 643-646.]). The elongated displacement ellipsoids of atoms Cl5 and C3 show traces of disorder, which means that atoms C3 and Cl5 are quite mobile at room temperature, but examination of a difference map of the two atoms does show they exist as distinct atoms, so this kind of disorder could be dynamic disorder. All the tri­methyl­sulfonium cations are linked by the anionic {[SbCl4]-}n polymer framework, with weak C1-H1A...Cl3i, C1-H1B...Cl1ii, C2-H2C...Cl1 and C3-H3B...Cl2iii hydrogen bonds, forming a three-dimensional structure (Fig. 2[link] and Table 2[link]).

Salt (II)[link] has an asymmetric unit that consists of a disordered tri­methyl­sulfonium cation and a [CdCl3]- anion. The other three chloride ligands (Cl1ii, Cl2ii and Clii) are generated by the (x - [{1\over 2}], -y + [{3\over 2}], -z + 1) twofold screw-axis operation (Fig. 3[link]). The tri­methyl­sulfonium cation of (II) is more mobile than that of (I)[link], and is disordered over two sets of sites in a ratio of 0.791 (4):0.209 (4), but the bond lengths and angles of the cations are similar to those of (I)[link], which is consistent with structures reported in the literature (Hess et al., 2007[Hess, D., Gorlov, M., Fischer, A. & Kloo, L. (2007). Z. Anorg. Allg. Chem. 633, 643-646.]). The Cd atoms are hexa­coordinated in a slightly distorted octa­hedral Cd([mu]-Cl)6 arrangement. The Cd-Cl bond lengths are in the range 2.6159 (11)-2.6647 (11) Å, which are comparable with those found in a previously reported structure (Corradi et al., 1997[Corradi, A. B., Cramarossa, M. R. & Saradini, M. (1997). Inorg. Chim. Acta, 257, 19-26.]). The Cl-Cd-Cl angles are in the ranges 82.74 (4)-98.07 (4) and 178.93 (4)-179.22 (2)°, deviating slightly from ideal octa­hedral angle values. The octa­hedra are linked by two opposite shared faces, giving rise to infinite {[Cd([mu]-Cl)3]-}n chains parallel to the [100] direction, with a Cd1...Cd1ii distance of 3.3723 (8) Å, which is much shorter than those reported in other one-dimensional cadmium polymers bridged by Cl atoms (Huang et al., 1998[Huang, C.-F., Wei, H.-H., Lee, G.-H. & Wang, Y. (1998). Inorg. Chim. Acta, 279, 233-237.]; Hu et al., 2003[Hu, C., Li, Q. & Englert, U. (2003). CrystEngComm, 5, 519-529.]; Laskar et al., 2002[Laskar, I. R., Mostafa, G., Maji, T. K., Das, D., Welch, A. J. & Chaudhuri, N. R. (2002). J. Chem. Soc. Dalton Trans. 31, 1066-1071.]), and a Cd1i...Cd1...Cd1ii angle of 178.80 (1)° [symmetry codes: (i) x + [{1\over 2}], -y + [{3\over 2}], -z + 1; (ii) x - [{1\over 2}], -y + [{3\over 2}], -z + 1], indicating that the polymer chain icis nearly linear. Thus, all the chloride ligands act as bridges between two consecutive Cd atoms, and each pair of consecutive Cd atoms is linked by three corner-shared bridging chloride ligands (Fig. 4[link]). The tri­methyl­sulfonium cations are located in the inter-chain space and the charges of the cations are balanced by the anionic {[Cd([mu]-Cl)3]-}n polymer chains.

There are numerous nonclassical C-H...Cl hydrogen bonds in the structure of (II)[link]. The crystal structure is stabilized by C3-H3B...Cl1(x + 1, y, z) and C3-H3C...Cl1(x + [{1\over 2}], -y + [{1\over 2}], -z + 1) hydrogen-bond inter­actions, linking the cations and anionic chains (Fig. 4[link] and Table 3[link]).

Our original inter­est in (I)[link] and (II)[link] lay mainly in their potential as mol­ecular ferroelectric materials. The variable-temperature dielectric constants of (I)[link] and (II)[link] were initially measured on powder samples in the form of pressed pellets with a sandwich architecture, Ag/sample/Ag, in the temperature range 275-345 K. However, measurement of their dielectric properties with varying temperature did not show any dielectric anomaly but only a smooth increase over the measured temperature range. The steady dielectric constants of the two compounds are the result of the contribution of electronic and ionic displacements. A contribution from dipolar reorientation does not occur under the measuring conditions used here, although it is what we are searching for. This implies that there is no structural phase transition within this temperature range and so (I)[link] and (II)[link] are not ferroelectric materials, unlike those reported earlier (Ye et al., 2009[Ye, H.-Y., Fu, D.-W., Zhang, Y., Zhang, W., Xiong, R.-G. & Huang, S.-D. (2009). J. Am. Chem. Soc. 131, 42-43.]; Fu et al., 2008[Fu, D.-W., Zhang, W. & Xiong, R.-G. (2008). Dalton Trans. pp. 3946-3948.]). Other related materials are currently being investigated for ferroelectric activity.

In summary, two novel organic-inorganic complexes which contain the same cation and different kinds of polymeric anions were prepared, and the possibility of undergoing a phase transition was investigated. They form two distinct types of polymeric anions linked by tri­methyl­sulfonium cations with different C-H...Cl nonclassical hydrogen-bonding inter­actions, forming three-dimensional structures with different packing modes.

Table 1
Experimental details

  (I) (II)
Crystal data
Chemical formula (C3H9S)[SbCl4] (C3H9S)[CdCl3]
Mr 340.71 295.91
Crystal system, space group Monoclinic, C2/c Orthorhombic, P212121
Temperature (K) 293 293
a, b, c (Å) 13.182 (3), 13.214 (3), 12.374 (3) 6.7443 (13), 9.0050 (18), 15.224 (3)
[alpha], [beta], [gamma] (°) 90, 91.58 (3), 90 90, 90, 90
V3) 2154.7 (7) 924.6 (3)
Z 8 4
Radiation type Mo K[alpha] Mo K[alpha]
[mu] (mm-1) 3.68 3.37
Crystal size (mm) 0.36 × 0.32 × 0.28 0.2 × 0.2 × 0.2
 
Data collection
Diffractometer Rigaku Mercury2 diffractometer Rigaku Mercury2 diffractometer
Absorption correction Multi-scan (CrystalClear; Rigaku, 2005[Rigaku (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.]) Multi-scan (CrystalClear; Rigaku, 2005[Rigaku (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.])
Tmin, Tmax 0.275, 0.355 0.500, 0.513
No. of measured, independent and observed [I > 2[sigma](I)] reflections 10903, 2461, 2335 8566, 2108, 1990
Rint 0.031 0.038
(sin [theta]/[lambda])max-1) 0.649 0.649
 
Refinement
R[F2 > 2[sigma](F2)], wR(F2), S 0.020, 0.045, 1.22 0.029, 0.077, 1.01
No. of reflections 2461 2108
No. of parameters 89 117
No. of restraints 0 198
H-atom treatment H-atom parameters constrained H-atom parameters constrained
[Delta][rho]max, [Delta][rho]min (e Å-3) 0.49, -0.39 1.25, -0.79
Absolute structure - Flack (1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.]), with 868 Friedel pairs
Absolute structure parameter - -0.01 (7)
Computer programs: CrystalClear (Rigaku, 2005[Rigaku (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.]), SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]), DIAMOND (Brandenburg & Putz, 2005[Brandenburg, K. & Putz, H. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany.]) and SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]).

Table 2
Hydrogen-bond geometry (Å, °) for (I)[link]

D-H...A D-H H...A D...A D-H...A
C1-H1A...Cl3i 0.96 2.83 3.765 (3) 165
C1-H1B...Cl1ii 0.96 2.83 3.771 (3) 166
C2-H2C...Cl1 0.96 2.81 3.610 (3) 142
C3-H3B...Cl2iii 0.96 2.81 3.695 (3) 153
Symmetry codes: (i) [-x, y, -z+{\script{3\over 2}}]; (ii) [x, -y, z-{\script{1\over 2}}]; (iii) [x+{\script{1\over 2}}, -y+{\script{1\over 2}}, z-{\script{1\over 2}}].

Table 3
Hydrogen-bond geometry (Å, °) for (II)[link]

D-H...A D-H H...A D...A D-H...A
C3-H3C...Cl1iii 0.96 2.72 3.596 (10) 152
C3-H3B...Cl1iv 0.96 3.06 3.592 (9) 116
Symmetry codes: (iii) [x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+1]; (iv) x+1, y, z.

Supplementary data for this paper are available from the IUCr electronic archives (Reference: KU3119 ). Services for accessing these data are described at the back of the journal.


Acknowledgements

This work was supported by the National Natural Science Foundation of China (grant No. 91022003).

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Acta Cryst (2014). C70, 169-172   [ doi:10.1107/S2053229613034207 ]