The resonance Raman profile of a nickel Schiff base complex at 10 K

Abstract

The resonance Raman profile for the Schiff-base complex N,N′-bis(salicyladehyde)- o-diaminobenzene nickel (II) has been measured at 290 and 10 K and the main peaks assigned. A broad fluorescence with a maximum at ca. 672 nm reduced the sensitivity of some measurements at room temperature but at 10 K this band had shifted sufficiently to enable definitive Raman spectra to be recorded over the entire range of exciting lines used. A second sharper fluorescence was observed and in this case, the band position was dependent on the exciting line, occurring about 7.4 nm from it. More bands were observed in the resonance profile at 10 K than at room temperature, and two electronic transitions which were not resolved in the electronic spectra at either temperature were characterized. The lowest-energy electronic transitions are charge-transfer transitions between a ground state, which is largely composed of phenyl ring and oxygen orbitals and an excited state, composed mainly of oxygen and nickel orbitals. The electronic spectrum in the visible region is assigned on the basis of the resonance profile.