An Iminophosphonamido‐Chlorosilylene as a Strong σ‐Donating NHSi Ligand: Synthesis and Coordination Chemistry

Abstract

AbstractTheN‐heterocyclic silylene (NHSi) [Ph2P(tBuN)2]SiCl (1), supported by an iminophosphonamide ligand, was obtained from the dehydrochlorination of [Ph2P(tBuN)2]SiHCl2(2) with LiN(SiMe3)2. NHSi1contains an extremely high‐energy HOMO level and consequently displays unique coordination behavior toward RhIcomplexes. When1was treated with 1/4 of an equivalent of [RhCl(cod)]2(cod=1,5‐cyclooctadiene), the 14‐electron Y‐shaped bis(chlorosilylene) RhIcomplex5was obtained as dark purple crystals. The reaction of1with 1/6 of an equivalent of [RhCl(cod)]2yielded the cationic tris(silylene)‐RhIcomplex [6]+⋅Cl−as red crystals, wherein a two‐coordinated silylene ligand engages in a Si=Rh double bond. A structural analysis of5and [6]+⋅Cl−revealed that the central rhodium atoms adopt trigonal and square‐planar coordination geometries, respectively, with considerably shortened Si‐Rh bonds [5: 2.1605(5) Å; [6]+: 2.133(1) Å].