Studies on Oxovanadium(IV), Nickel(II), Copper(II), and Palladium(II) Complexes with 5,14-Dihydro-6,8,15,17-Tetramethyldibenzo[b,i][1,4,8,11]Tetraazacyclotetradecine

The oxovanadium(IV), nickel(II), copper(II), and palladium(II) complexes of 5,14-dihydro-6,8,15,17-tetramethyldibenzo-[b,i][1,4,8,11]tetraazacyclotetradecine have been prepared and investigated by the use of mass, electronic, vibrational, NMR, ESR, and ESCA spectroscopy. In view of the ligand field spectra, the oxovanadium(IV) complex presumes the square-pyramidal configuration and the other complexes assume the square-planar configurations. A strong IR band due to the V=O stretching mode was observed at 970 cm−1 for the oxovanadium(IV) complex. As judged by the spin Hamiltonian parameters, the oxovanadium(IV) complex is in C4v coordination symmetry with an unpaired electron in the dxy orbital and the copper(II) complex is confirmed to have D2h coordination symmetry with an unpaired electron in the dx2−y2 orbital. The result of ESCA spectra is comparable to those obtained for porphyrins.