Chromophoric Nickel(II) and Cobalt(II) Complexes Based on New o-Iminobenzoquinone

Bis(ligand) coordination compounds of Ni(II) (I) and Co(II) (II) are synthesized from the o-iminobenzoquinone ligand (6-((2,6-diisopropylphenyl)imino)-3-methoxy-4-(2,4,4-trimethylpentan-2-yl)cyclohexa-2,4-dien-1-one). The molecular and crystal structures of complexes I and II are determined by single-crystal XRD (CIF files CCDC nos. 2494475 (I) and 2494474 (II)). The electronic structures of compounds I and II are refined by magnetic susceptibility measurements and density functional theory calculations. The electrochemical behavior of complexes I and II is studied by cyclic voltammetry. According to the data of electronic absorption spectroscopy, the synthesized compounds are metal-complex chromophores intensely absorbing light (ε about 104 M–1 cm–1) in the visible and near-IR ranges due to the photoinduced intramolecular “ligand–ligand” charge transfer. A comprehensive study of the thermal properties (thermal stability, volatility) using differential scanning calorimetry, thermogravimetry, and Knudsen effusion method for the Ni(II) (I) and Co(II) (II) complexes shows that they are appropriate for further testing in heterojunction optoelectronic devices with the vacuum layer sputtering technology.