Synthesis, structure determination and characterization by UV-Vis and IR spectroscopy of bis(diisopropylammonium) cis-dichloridobis-(oxalato-kappa O-2(1),O-2)stannate(IV)

The organic-inorganic title salt, (C6H16N)(2)[Sn(C2O4)(2)Cl-2] or ((Pr2NH2)-Pr-i)(2)-[Sn(C2O4)(2)Cl-2], was obtained by reacting bis(diisopropylammonium) oxalate with tin(IV) chloride dihydrate in methanol. The Sn-IV atom is coordinated by two chelating oxalate ligands and two chloride ions in cis positions, giving rise to an [Sn(C2O4)(2)Cl-2](2-) anion (point group symmetry 2), with the Sn-IV atom in a slightly distorted octahedral coordination. The cohesion of the crystal structure is ensured by the formation of N-H center dot center dot center dot O hydrogen bonding between ((Pr2NH2)-Pr-i)(+) cations and [SnCl2(C2O4)(2)](2-) anions. This gives rise to an infinite chain structure extending parallel to [101]. The main inter-chain interactions are van der Waals forces. The electronic spectrum of the title compound displays only one high intensity band in the UV region assignable to ligand-metal ion charge-transfer (LMCT) transitions. An IR spectrum was also recorded and is discussed.