A S=3/2 Cr(III) Complex In A Square‐Capping NHC Framework

Abstract

Deprotonation of our pentadentate N‐Heterocyclic Carbene (NHC) ligand with lithium diisopropylamine in tetrahydrofuran and subsequent salt metathesis with CrCl3THF3 readily forms the complex PhCC4MeCrCl (1), a S=3/2 species in moderate yield. DFT calculations reveal three singly occupied molecular orbitals with π‐backbonding character to the square‐capping framework, UV‐Vis spectroscopy reveals 3 bands ascribed to d‐to‐d transitions, and cyclic voltammetry reveals an irreversible and quazi‐reversible reduction events as well as an irreversible oxidation event. We attempted to exchange the chloride ligand of 1 through salt‐metathesis with lithium phenylacetylide without success, the absence of reactivity is rationalized considering our XRD and DFT results.