PtII2 and PtIII2 dimers containing a Pt2 (2,2′-bipyridine)2(μ-N,N-dimethyl-guanidinato)2 unit

The syntheses and crystal structures of the title Pt-2(II) and Pt-2(III) dimers doubly bridged with N, N-dimethylguanidinate ligands, namely bis(mu-N,N-dimethylguanidinato) bis[(2,2'-bipyridine)platinum( II)](Pt-Pt) bis(hexafluorophosphate) acetonitrile disolvate, [Pt-2(II)(C3H8N3)(2)(C10H8N2)(2)]( PF6)(2)(.)2CH(3)CN, (I), and guanidinium bis(mu-N, N-dimethylguanidinato) bis[( 2,2'- bipyridine) sulfatoplatinum(III)](Pt-Pt) bis(hexafluorophosphate) nitrate hexahydrate, (C3H10N3)[Pt-2(III)(C3H8N3)(2)(SO4)(2)(C10H8N2) (2)]NO(3)(.)6H(2)O, (II), are reported. The oxidation of the Pt-2(II) dimer into the Pt2 III dimer results in a marked shortening of the Pt-Pt distance from 2.8512 (6) to 2.5656 (4) angstrom. The change is mainly compensated for by the change in the dihedral angle between the two Pt coordination planes upon oxidation, from 21.9 (2) to 16.9 (3)degrees. We attribute the relatively strong one-dimensional stack of dimers achieved in the Pt-2(II) compound in part to the strong Pt-II (...) C( bpy) associations ( bpy is 2,2-bipyridine) in the crystal structure [ Pt (...) C = 3.416 ( 10) and 3.361 (12) angstrom].