Bis(tetra-n-butylammonium) (a redetermination at 150 K) and bis(tetraphenylarsonium) bis(1,3-dithiole-2-thione-4,5-dithiolato)zinc(II) (at 300 K)

Abstract

The title compounds are salts of the general form (Q(+))(2)[Zn(dmit)(2)](2-), where dmit corresponds to the ligand (C(3)S(5))(-) present in both and Q(+) to the counter-cations ((n)Bu(4)N)(+) [or C(16)H(36)N(+)] and (Ph(4)As)(+) [or C(24)H(20)As(+)], respectively. In the first case, Zn is in the 4e special positions of space group C2/c and hence the [Zn(dmit)(2)](2-) dianion possesses twofold axial crystallographic symmetry. Including these, there are now 11 known examples of [Zn(dmit)(2)](2-) or its analogues, with O replacing the exocyclic thione S, and [Zn(dmio)(2)](2-) dianions in nine structures with various Q. Comparison of these reveals a remarkable variation in details of the conformation which the dianion may adopt in terms of Zn coordination, equivalence of the Zn-S bond lengths, displacement of Zn from the plane of the ligand and overall dianion shape.

Vibrational spectra of bis(dmit) complexes of main group metals: IR, Raman and ab initio calculations

“…The calculated optimised C 2 gas phase structure is just the same as that found in the solid state, ignoring the inter-anionic Sb-S interactions: the gas-phase calculated and experimental solid state intra-atomic distances differed by less than 6%. 6,2004 The results between the three basis functions do not exhibit significant variations as also found for the zincate complex discussed earlier, an indication that polarization functions do not play a qualitative role in this geometry calculation. Analysing the differences between the several calculations methods, it is noticeable that the RHF method provided the closest match to the experimental values, similarly as observed for the dmit zinc complex.…”

“…In the Raman spectrum, the main band in this region was observed at 310 cm -1 with a shoulder at 302 cm -1 . At 279 cm -1 in the 6,2004 infrared spectrum a band was observed, while the Raman band in this region was found at 283 cm -1 with a low intensity. In the region between 260 and 240 cm -1 , two bands at 252 and 247 cm -1 were observed in the infrared, while in the Raman spectrum just one band was observed at 249 cm -1 .…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] For instance, D 2d symmetry is present in Cu(II) and Zn(II) complexes, D 2h symmetry in Ni(II) complexes and C 2 symmetry for complexes of the Group 15 elements, Sb and Bi, in their trivalent oxidation state.…”

“…All the crystal structures of these complexes are known, [6][7][8][9][10][11][12][13][14][15] including those of the tetraethylammonium salts, a family showing an increasing degree of inter-anion interactions from the Zn to Bi complex. Therefore we could assess M-S inter-anion interactions in the solid state, by carefully comparing the gas-phase calculation to the solid-state bulk spectra of these systems.…”

“…Therefore we could assess M-S inter-anion interactions in the solid state, by carefully comparing the gas-phase calculation to the solid-state bulk spectra of these systems. The [Zn(dmit) 2 ] -2 anions in complex salts [Q] 2 [Zn(dmit) 2 ] (Q = NEt 4 , NBu 4 , ferrocenyl-CH 2 NMe 3 , 1,4-Me 2 -pyridinium, PPh 4 and AsPh 4 ) [6][7][8][9] in the solid state, invariably have distorted tetrahedral geometries, and four coordinate zinc centres, with no anionanion interactions apart for very weak S---S contacts close to its van der Waals radii sum. The distortion from an ideal zinc tetrahedral coordination is a consequence of the near 95 o bite angles of the chelating dmit ligands.…”