In memory of Davood Amiri (Feb 1974–Apr 2022)
Abstract
We report the use of alkaline earth metals magnesium and calcium for the reduction
of the cobalt(II) complex [
i
Pr2NN]Co(μ-Cl)2Li(thf)2 [
i
Pr2NN = 2,4-bis(2,6-diisopropylphenylimido)pentyl] that resulted in heterotrimetallic
dinitrogen complexes with a rare example of a [Co–N2–M–N2–Co] core where M = Mg and Ca. The dinitrogen ligands in these new complexes showed
weakened N–N bonds, as judged by infrared spectroscopy, and the crystal structures
of the complexes were illustrated by X-ray crystallography. These cobalt complexes
can be isolated as pure solids that are stable in solutions of non-coordinating solvents
such as n-pentane or cyclohexane, as well as tetrahydrofuran. These results demonstrate the
correlation between the binding mode of the Lewis acid and N–N weakening in heterotrimetallic
dinitrogen complexes.
Key words
cobalt - dinitrogen activation - β-diketiminates - alkaline earth metals - X-ray crystallography
