Co-crystallization of Oxalate Salts of Monoprotonated Amines with a Double Sn-Ph Bond Cleavage

Two oxalate compounds [(C4H7N2)3][Sb(C2O4)3] (1) and [(Et3NH)][SnPhCl(C2O4)2] (2), have been isolated and characterized by single-crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic system, space group P21/c with a=13.3944 (6) Å, b=11.3554 (5) Å, c=16.3314 (7) Å, β=107.206 (1), V=2372.82 (18) Å3 and Z=4. Compound 2 crystallizes in the monoclinic system, space group P21/n with a=8.6903 (4) Å, b=15.3844 (8) Å, c=20.3144 (10) Å, β=100.869 (2), V=2667.2 (2) Å3 and Z=4. The complex-anion [Sb(O2CCO2)3]3- of the compound 1 adopts a distorted pentagonal pyramidal arrangement with monochelating oxalates. The asymmetric unit of 1 consists of three 2-methyl-1H-imidazolium cations, C4H7N2+, three oxalate anions, C2O42-, and one antimony (III) ion, Sb3+. From a supramolecular point of view, in 1 complex-anions are connected by cations through N-H•••(O,O) and N-H•••O hydrogen bonds involving the two oxalates of the basal plane into sheets which are then connected via the remaining oxalate and cations through N-H•••O hydrogen bonds to give rise to a three-dimensional structure. The complex-anion of 2 is comprised of a tin centre linked to a chlorine atom and a phenyl group, and cis-chelated by two oxalates in a distorted octahedral fashion. Each triethylammonium cation is connected to the complex-anion through bifurcated N-H•••(O,O) hydrogen bonds. These interactions lead to a discrete structure. A double Sn-C bond cleavage has occurred during the process of the formation of the compound 2. In both complounds 1 and 2, one cation exhibits some positional disorder.