Homoleptic Two-Coordinate Silylamido Complexes of Chromium(I), Manganese(I), and Cobalt(I)

Abstract

Anionic two-coordinate complexes of first-row transition-metal(I) centres are rare molecules that are expected to reveal new magnetic properties and reactivity. Recently, we demonstrated that a N(SiMe3)2(-) ligand set, which is unable to prevent dimerisation or extraneous ligand coordination at the +2 oxidation state of iron, was nonetheless able to stabilise anionic two-coordinate Fe(I) complexes even in the presence of a Lewis base. We now report analogous Cr(I) and Co(I) complexes with exclusively this amido ligand and the isolation of a [Mn(I){N(SiMe3)2}2]2(2-) dimer that features a Mn-Mn bond. Additionally, by increasing the steric hindrance of the ligand set, the two-coordinate complex [Mn(I){N(Dipp)(SiMe3)}2](-) was isolated (Dipp=2,6-iPr2-C6H3). Characterisation of these compounds by using X-ray crystallography, NMR spectroscopy, and magnetic susceptibility measurements is provided along with ligand-field analysis based on CASSCF/NEVPT2 ab initio calculations.

Keywords: N ligands; ab initio calculations; coordination modes; magnetic properties; transition metals.