Synthesis, Structures, and Properties of the Zn(II), Cu(II), Co(II), and Ni(II) Bis(chelate) Complexes Based on 2,4,9,11-Tetra-tert-butylbenzo[5,6][1,4]oxazino[2,3-b]phenoxazin-1-ol

A series of zinc, copper, cobalt, and nickel bis(chelate) complexes ( I – IV ) with 2,4,9,11-tetra- tert -butylbenzo[5,6][1,4]oxazino[2,3- b ]phenoxazin-1-ol (LН) of the general formula ML 2 is synthesized. The spatial and electronic structures of the synthesized coordination compounds are studied by the density functional theory (DFT B3LYP/6-311++g(d,p)). The molecular structure of the adduct of the copper complex with pyridine ( II ·Py) is determined by X-ray diffraction (CIF file CCDC no. 2113818). The spectral characteristics of the ligand and related complexes are studied.