Iron- and Cobalt-Catalyzed Synthesis of Carbene Phosphinidenes.

Kuntal Pal,Oliver B Hemming,Richard A Layfield,David J Evans,Benjamin M Day,Thomas Pugh

doi:10.1002/anie.201508303

Kuntal Pal, Oliver B Hemming + Show 4 more

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https://doi.org/10.1002/anie.201508303

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Abstract

In the presence of stoichiometric or catalytic amounts of [M{N(SiMe3)2}2] (M=Fe, Co), N‐heterocyclic carbenes (NHCs) react with primary phosphines to give a series of carbene phosphinidenes of the type (NHC)⋅PAr. The formation of (IMe4)⋅PMes (Mes=mesityl) is also catalyzed by the phosphinidene‐bridged complex [(IMe4)2Fe(μ‐PMes)]2, which provides evidence for metal‐catalyzed phosphinidene transfer.

Highlights

In the presence of stoichiometric or catalytic amounts of [M{N(SiMe3)2}2] (M = Fe, Co), N-heterocyclic carbenes (NHCs) react with primary phosphines to give a series of carbene phosphinidenes of the type (NHC)·PAr
Our interest in low-coordinate transition-metal chemistry has focused on iron and cobalt complexes of N-heterocyclic carbene (NHC) ligands.[8,9,10,11,12]
NHC-stabilized iron and cobalt complexes of terminal or bridging phosphinidene ligands are currently unknown, we are interested in developing the phosphinidene-transfer chemistry of complexes of the type [(NHC)nM(PR)] (M = Fe, Co)

Summary

Introduction

The structures of 1Fe and 1Co (Figure 1; see Table S1 in the Supporting Information) are very similar to those of previously reported [(NHC)M(N’’)2] complexes.[8,9] The reactions of 1Fe and 1Co with MesPH2 in toluene produced dark green solutions, from which green crystals of the phosphinidenebridged dimetallic compounds [(IMe4)2M(m-PMes)]2·toluene were obtained (2Fe·toluene and 2Co·toluene). The compounds 2Fe·toluene and 2Co·toluene can be synthesized by combining IMe4, [M(N’’)2], and MesPH2 in the observed 2:1:1 stoichiometry, and isolated in yields of 45 % and

Results

Conclusion