σ‑GeH and Germyl Cationic Pt(II) Complexes

Description

The low electron count Pt(II) complexes [Pt(NHC′)(NHC)]- [BArF] (where NHC is a N-heterocyclic carbene ligand and NHC′ its metalated form) react with tertiary hydrogermanes HGeR3 at room temperature to generate the 14-electron platinum(II) germyl derivatives [Pt(GeR3)(NHC)2][BArF]. Low-temperature NMR studies allowed us to detect and characterize spectroscopically some of the σ-GeH intermediates [Pt(η2-HGeR3)(NHC′)(NHC)][BArF] that evolve into the platinum-germyl species. One of these compounds has been characterized by X-ray diffraction studies, and the interaction of the H−Ge bond with the platinum center has been analyzed in detail by computational methods, which suggest that the main contribution is the donation of the H−Ge to a σ*(Pt−C) orbital, but backdonation from the platinum to the σ*(Ge−H) orbital is significant. Primary and secondary hydrogermanes also produce the corresponding platinum-germyl complexes, a result that contrasts with the reactivity observed with primary silanes, in which carbon−silicon bond-forming reactions have been reported. According to density functional theory calculations, the formation of Pt−Ge/C−H bonds is both kinetically and thermodynamically preferred over the competitive reaction pathway leading to Pt−H/C−Ge bonds.

Abstract

Ministerio de Ciencia e Innovación PID2019-109312GB-I00, PID2019-106184GB-I00, RED2018-102387-T

Abstract

Junta de Andalucía P20_00513

Abstract

Universidad de Oviedo MU-21-UP2021-030 53307942

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