Synthesis, characterization and electrochemical investigation of hetaryl chromium(0) aminocarbene complexes

In this contribution a new series of aminocarbene complexes of chromium(0) was synthesized, where the originally used phenyl substituent in the compound I pentacarbonyl[(N,N-dimethylamino)(phenyl)carbene]chromium(0), was replaced by various five-membered heteroaromatic rings: furan (II), thiophene (III) and N-Me-pyrrol (IV), attached either by their position 2 or 3 (Fig. 1). The compounds were characterized by 1H and 13C NMR and elemental analysis. In the second part of this work an electrochemical investigation in acetonitrile followed in order to understand more deeply the oxidation and reduction process and to analyze the relative contribution of inductive and mesomeric effects of the heterocycles to the reduction of the chromium aminocarbenes. Their electrochemical behavior was compared with that obtained for the phenyl derivative I, the interpretation was correlated with quantum chemical calculations and the differences were discussed.