Phenyl-substituted biliazine: Structure and spectroscopy

In this report, we present four new phenyl-substituted biliazine (H₂BlzPhH) metal complexes with the metals Co(II), Ni(II), Cu(II), and Zn(II). As in the previously reported unsubstituted biliazine [Schrage BR, Nemykin VN, Ziegler CJ. Chem. Commun. 2020; 56: 6628-6631], these metal adducts were formed via template reactions using a pyrazole-modified diiminoisoindoline. The modification of the biliazine rings with phenyl groups off the pyrazole units reduces their solubilities. We were able to structurally characterize the Co(BlzPhH) and Ni(BlzPhH)(py)₂ complexes by using single crystal X-ray diffraction, which were in good agreement with previously reported biliazine systems. Spectroscopically, these compounds exhibit moderately intense bands in the visible region due to π orbital-based transitions, and we probed the electronic structures of these four phthalocyanine analogs by DFT and TD-DFT methods.