Synthesis and the Optical and Electrochemical Properties of Indium(III) Bis(arylimino)acenaphthene Complexes

Aryl bis­(imino)­acenaphthenes (Ar-BIANs) are well-established rigid and sterically bulky diimine ligands, which are redox-noninnocent and versatile π-acceptors due to their low-lying π* orbitals and are frequently used to bind transition metals. However, the coordination chemistry of Ar-BIAN ligands to main group elements is not as well-developed as that of their transition metal counterparts. In particular, there are no comprehensive studies describing the spectroscopic and electrochemical properties of main group Ar-BIAN complexes. Herein, we report the synthesis and full characterization of a series of new indium­(III) Ar-BIAN complexes, bearing 2,6-dialkyl (1b and 2b), 4-nitro (3b), and 4-dimethylamino (4b) groups at the aryl-diimine part of the ligand. Their optical and electrochemical properties have been revealed by UV–vis spectroscopy and cyclic voltammetry, respectively. Additionally, DFT calculations were performed to gain insights into the nature of the properties displayed.