Structural chemistry of dihalogenopalladium(II) and platinum(II) complexes of heteroleptic N,S- and N,Se- donor ligands based on the 2-organochalcogenomethylpyridine motif

The structural chemistry of dihalogenopalladium(II) and platinum(II) complexes of 2-organochalcogenomethylpyridine ligands is described. Complexes with a methyl group in the 6-position of the pyridyl ring, 6-MepyCH(2)ER, form dimeric complexes [trans-PdX(2)(mu-6-MepyCH(2)SePh-N,Se)](2) (X = Br (1), I (2)) or mononuclear complexes trans-PdI(2)(6-MepyCH(2)SR-N)(2) (R = Me (5), Ph (6)). Absence of a 6-methyl substituent results in the bidentate configuration observed for PdI(2)(pyCH(2)SePh-N,Se) (3) and PdI(2)(4-MepyCH(2)SMeN, S) (4). Related platinum(II) complexes are mononuclear including PtCl(2)(6-MepyCH(2)SPh-N,S) (8) as an analogue of trimeric [trans-PdCl(2)(mu-6-MepyCH(2)SPh-N,S)](3). Differences between palladium and platinum appear to result from a combination of steric and electronic factors.