Studies on Mixed Valence Complexes of Platinum and Palladium. II. The Crystal Structures of [Pt(tn)2][PtCl2(tn)2](BF4)4, [Pt(tn)2][PtBr2(tn)2](ClO4)4, and [Pt(tn)2][PtBr2(tn)2](BF4)4

Abstract The crystal structures of Pt(II)–Pt(IV) complexes, [Pt(tn)2][PtCl2(tn)2](BF4)4 (1), [Pt(tn)2][PtBr2(tn)2](ClO4)4 (2), and [Pt(tn)2][PtBr2(tn)2](BF4)4 (3) have been determined by the single-crystal X-ray diffraction method, where tn denotes trimethylenediamine. The crystals of these complexes are isomorphous with one another and the space group is A222 with a=10.790(2), b=13.872(2), c=10.287(1) Å for 1, a=11.003(6), b=13.979(6), c=10.355(4) Å for 2, and a=10.925(3), b=13.862(3), c=10.291(1) Å for 3. The structures were determined by the heavy atom method and refined by the block-diagonal least-squares method to give the disagreement factor 0.082, 0.089, and 0.086 for 1, 2, and 3, respectively. Each crystal comprises infinite PtII…X–PtIV–X… chains running parallel to the a-axis. In the chain, tetragonal bipyramidal [PtIVX2(tn)2]2+ (X=Cl or Br) and square planar [PtII(tn)2]2+ units are stacked alternately. Two of the fluorine or oxygen atoms of the counter anion are hydrogen-bonded to the nitrogen atoms of the ligand, contributing to the formation of an infinite chain.