Preparation and crystal structures of novel bis(maleodintriledithiolato) platinum(III) complexes

[Pt(NH2Oc)4][Pt(mnt)2]2 was prepared by oxidation of [Pt(NH2Oc)4][Pt(mnt)2] with iodine (mnt stands for maleodinitriledithiolate and Oc for octyl). UV and IR spectra confirmed that the [Pt(mnt)2]2− and not the [Pt(NH2Oc)4]2+ unit was oxidized, yielding [Pt(mnt)2]− entities where platinum is present in the uncommon formal oxidation state III. [Pt(NH2Oc)4][Pt(mnt)2] crystallized from acetone or dimethyl sulfoxide with two solvent molecules per formula unit as revealed by X-ray diffraction studies of single crystals. The [Pt(mnt)2]− moieties formed parallel pairs in the crystals spaced by 3.57 Å as a consequence of intermolecular π-interactions between mnt ligands. The electrostatic attractions between the oppositely charged [Pt(NH2Oc)4]2+ and [Pt(mnt)2]2 2− units or the π-interactions between neighboring [Pt(mnt)2]− units were obviously not sufficient to cause a stacking of the coordination units as in the case of [Pt(NH2Oc)4][Pt(mnt)2] or [Pt(CNCH3)4][Pt(mnt)2]2; it appears that the crystal structure of [Pt(NH2Oc)4][Pt(mnt)2]2 is markedly influenced by packing of the alkyl groups.