Quantum Chemical Calculations of the Structures and Electronic Properties of N,N‘- Bis(3,5-dibromosalicylidene)-1,2-diaminobenzene and Its Cobalt(II) Complex. Origin of the Redox Activity of the Cobalt Complex

The geometry, electronic structure, and UV−visible spectra of N,N‘-bis(3,5-dibromosalicylidene)-1,2-diaminobenzene and its Co(II) complex are studied by means of AM1 and INDO/1 calculations for the conformational analysis and INDO/S-CI for the UV−visible spectra. The color of the ligand is justified and the catalytic redox activity of the Co(II) complex is explained on the bases of the electronic transitions associated with the spectroscopic features and the electronic characteristics of the redox states.