Sterically hindered metal alkenyls. Part 1. Synthesis, reactions, and crystal and molecular structures of some palladium and platinum σ-alkenyls

Abstract

The compounds trans-[PtBr{C(C₁₀H₁₅)CH₂}(PEt₃)₂](1)(C₁₀H₁₅= adamant-1-yl), trans-[MBr{C(C₁₀H₇)CMe₂}(PEt₃)₂][M = Pd (2) or Pt (3); C₁₀H₇= naphth-1-yl], and trans-[MBr{C(Ph)CMe₂}(PEt₃)₂][M = Pd (4) or Pt (5)] have been prepared from Grignard [for (2) and (3)] or lithium reagents [for (1), (4), and (5)] and appropriate dichlorobis(phosphine)metal derivatives. Full single-crystal X-ray data are reported for (1) and (3), and reveal unusually long Pt–C(sp²) bonds. Insertion reactions into these M–C bonds occur with MeNC [for (1), (3), and (5)], and with CO [for (1) and (3)]; the latter, the first reported insertion into a Pt–C(sp²) bond, occurs under mild conditions as expected for the abnormally long M–C bonds.