Transition Metal Silyl Complexes. 62.1 Platinum Dimethyl Complexes with Hemilabile P,N-Chelating Ligands: Synthesis, Structure, and Reactions with Iodotrimethylsilane and 1,2-Bis(dimethylsilyl)benzene

Reaction of (η 4 -2,5-norbornadiene)dimethylplatinum(II) with (2-diphenylphosphinoethyl)dimethylamine, (3-diphenylphosphinopropyl)dimethylamine, 2-diphenylphosphino- N, N -dimethylaniline, or ( o -diphenylphosphinobenzyl)dimethylamine resulted in the formation of the corresponding dimethyl platinum complexes containing the P,N-chelating ligands, while reaction with (diphenylphosphinomethyl)dimethylamine gave only the bis(phosphine) complex. Reaction of the P,N-chelated dimethyl complexes with iodotrimethylsilane stereoselectively gave the corresponding methyl iodo complexes in which only the methyl group trans to the phosphorus atom was exchanged. Reaction with 1,2-bis(dimethylsilyl)benzene yielded cyclic bis(silyl) complexes. Analogous experiments with (dppe)PtMe 2 revealed that the P,N-chelated complexes exhibit a considerably higher reactivity than the bis(phosphine) complex. The most interesting feature in the solid-state structures of [(κ 2 -P,N)-Ph 2 PC 2 H 4 NMe 2 ]PtMe 2, trans -[(κ 2 -P,N)-Ph 2 PC 6 H 4 -2-CH 2 NMe 2 ]Pt(I)Me, and [(κ 2 -P,N)-Ph 2 PC 6 H 4 -2-NMe 2 ]Pt[ o -(Me 2 Si) 2 C 6 H 4 ] is the very long Pt−N distances (221.0(7), 223.3(6), and 236.8(5) pm, respectively), showing that the nitrogen atom of the P,N-chelating ligand is only weakly bonded. The Pt−C and Pt−Si distances trans to nitrogen are much shorter (203.7(9), 230.4(2) pm) than those trans to phosphorus (206.9(8), 237.2(2) pm).