Structural Characterization, thermal studies, fluorescence and optical properties of metal carbonyl derivatives of N2O2 Schiff Base

Abstract

A series of four binuclear complexes [Cr2(CO)2L2] (1), [Mo2O4(L)2] (2), and [W2O4(L)2] (3) [Mo2O5(CO)L].H2O (4) were synthesized from the reaction of [M(CO)6] (M = Cr, Mo and W) with 6,6'-(([1,1'-biphenyl]-4,4' diylbis(azaneylylidene)) bis(methaneylylidene)) bis(2,4-dichlorophenol) H2L in THF. The structures of the ligand and its complexes were characterized using elemental studies, IR, mass, UV-vis and 1H NMR spectroscopy. Magnetic measurements showed diamagnetic properties for molybdenum and tungsten complexes and paramagnetic character for chromium complex. The thermal analyses for all metal complexes were also determined by the thermogravimetry technique. The thermodynamics parameters of complexes were calculated. Spectroscopic data revealed that H2L was coordinated as a tetradentate ligand through two imine nitrogen and two deprotonated phenolic oxygen atoms. The Schiff base ligand (H2L) and its complexes displayed fluorescence properties and can potentially serve as photoactive materials. The values of optical band gap energy (Eg) of the prepared complexes suggested that these compounds could be used as semiconductors.

Keywords

• benzidine; metal carbonyl complexes; fluorescence; optical properties