Aminolysis of Bis[bis(trimethylsilyl)amido]iron and -cobalt as a Versatile Route to N-Heterocyclic Carbene Complexes

Abstract

A range of new N-heterocyclic carbene complexes of iron(II) and cobalt(II) have been conveniently obtained by the aminolysis of bis[bis(trimethylsilyl)amido]iron and -cobalt precursors with imidazol(in)ium salts. Whereas sterically less hindered salts produced the tetrahedral complexes [M(carbene)2Cl2] (M = Fe), bulkier salts gave the three-coordinate [M(carbene){N(SiMe3)2}Cl] (M = Fe, Co), which serve as versatile precursors to a range of derivatives; mechanistic aspects of the reaction are discussed.

Carbon dioxide cleavage by a Ni 2 complex supported by a binucleating bis(N-heterocyclic carbene) framework

“…A related monocobalt complex with Cl − , N(SiMe 3 ) 2 − , and imidazole-based NHC ligands has previously been isolated and structurally characterized. 14 The 1 H NMR spectrum of a C 6 D 6 solution of 3 displays broad peaks between −70 and 90 ppm, consistent with a paramagnetic compound.…”

Synthesis of new iron–NHC complexes as catalysts for hydrosilylation reactions

“…Iron–NHC complexes are generally prepared via free carbenes (generated from deprotonation of imidazolium salts by a strong base) or by using iron amides . Recently, Chen and colleages have have elucidated new approaches to Fe–NHC complexes: (i) the electrochemical synthesis using imidazolium salts and metal plates and (ii) direct reaction of metal powders with imidazolium salts or silver–NHC complexes .…”

Iron complexes of a bidentate picolyl-NHC ligand: synthesis, structure and reactivity

“…The average Fe-C NHC and Fe-N HMDS bond lengths of the two enantiomers are 2.095(8) and 1.945(8) Å, respectively, comparable to those of the analogous literature complexes. 45,46 The average bite angle of the HL ligand in 2 is 88.1(3)°, wider than that in 1. The largest peak in the 1 H NMR spectrum of 2 in C 6 D 6 at 13.92 ppm has been tentatively assigned to the protons of the HMDS group.…”