Spectroscopic Studies of Transition Metal Complexes with 2, 2'-Diaminobiphenyl

Abstract

2, 2t-Diaminebiphenyl(dabp) c6mplexes with transjtion mAetalS, CO(II), Ni(II) and Cu(II), were studied by various spectroscopic techniques such as reflect.ance s-petral .X-ray diffwraAction, IR and ESR spectra, 2, 2'-Diamin6phenyl as a bidentate ligand was located between.H2O and vly- in a spectrochemical series. Trans hexa-coordinated structure was estimated for disubstituted complex except (Ni(dabp)2(NO3)s), based on the reflectance, far-infrared, ESR spectras and powder X-ray diffraction data, while cis-structure was postulated for (Ni(dabp)2(NO3)2). From the ESR spectrum of (CU(dabp)2CL2), elongated trans-tetragonal structure was assumed for this compound. The covalent bond character between Cu2+ ion and N atom in dabp was ascertained from thr ESR spectrum of the methanol solution of Cu(dabp)2(H2O)(CIO4)2. The far-infrared spectra were measured for metal-dabp complexes and the assignments of the bands associated with metal-N stretching vibrations were made. The assignments were also made for those hands associated with metal-halogen and metal-oxygen stretching vibrations. On the basis of these vibrational assignments, the bonding nature between metal atoms and ligands was discussed, and considerable degree of ionic character of the bonds between metal atom and halogen or NO3- was presumed.