Reaction of Dichloro(N-methylethylenediamine)platinum(II) PtmenCl_2 with Iodine: The Crystal Structure of Mixed-Valence Compound {[PtI_4] [PtI_6]} [(CH_3)_2NH_2]_4

摘要

The reaction of dichloro(N-methylethylenediamine)platinum(II) with iodine gave {[PtI_4][PtI_6]}[(CH_3)_2NH_2]_4 (I). Compound I was studied by X-ray diffraction. The crystals are triclinic, a = 7.833(2) A, b = 8.889(2) A, c = 13.737(3) A, alpha = 97.65(3) deg, beta = 97.46(3) deg, gamma = 114.13(3) deg, V = 857.0(3) A~3, Z= 1, space group P1-bar, R = 0.047 over 1431 reflections. This is a class I anionic mixed-valence compound. It is built of isolated centrosymmetrical square (platinum(II)) and octahedral (platinum(IV)) complexes, [PtI_4]~(2-) and [PtI_6]~(2-), respectively, and dimethylammonium cations. Average Pt~(II)-I and Pt~(IV)-I distances are 2.608(2) and 2.673(2) A, respectively. The structural units in the crystal are combined by a hydrogen-bond array.