Pt···Pt vs Pt···S Contacts Between Pt-Containing Heterobimetallic Lantern Complexes

A trio of Pt-based heterobimetallic lantern complexes of the form [(py)­PtM­(SAc)₄(py)] (M = Co, <b>1</b>; Ni, <b>2</b>; Zn, <b>3</b>) with unusual octahedral coordination of Pt­(II) was prepared from a reaction of [PtM­(SAc)₄] with excess pyridine. These dipyridine lantern complexes could be converted to monopyridine derivatives with gentle heat to give the series [PtM­(SAc)₄(py)] (M = Co, <b>4</b>; Ni, <b>5</b>; Zn, <b>6</b>). An additional family of the form [PtM­(SAc)₄(pyNH₂)] (M = Co, <b>7</b>; Ni, <b>8</b>; Zn, <b>9</b>) was synthesized from reaction of [PtM­(SAc)₄(OH₂)] or [PtM­(SAc)₄] with 4-aminopyridine. Dimethylsulfoxide and <i>N</i>,<i>N</i>-dimethylformamide were also determined to react with [PtM­(SAc)₄] (M = Co, Ni), respectively, to give [PtCo­(SAc)₄(DMSO)]­(DMSO), <b>10</b>, and [PtNi­(SAc)₄(DMF)]­(DMF), <b>11</b>. Structural and magnetic data for these compounds and those for two other previously published families, [PtM­(tba)₄(OH₂)] and [PtM­(SAc)₄(L)], L = OH₂, pyNO₂, are used to divide the structures among three distinct categories based on Pt···Pt and Pt···S distances. In general, the weaker donors H₂O and pyNO₂ seem to favor metallophilicity and antiferromagnetic coupling between 3d metal centers. When Pt···S interactions are favored over Pt···Pt ones, no coupling is observed and the p<i>K</i>_a of the pyridine donor correlates with the interlantern S···S distance. UV–vis–NIR electronic and ¹H NMR spectra provide complementary characterization as well