International Journal of Advanced Research in Chemical Science Volume 7, Issue 7, 2020, PP 1-12 ISSN No.: 2349-0403 DOI: https:// doi.org/10.20431/2349-0403.0707001 www.arcjournals.org International Journal of Advanced Research in Chemical Science Page | 1 Spectroscopic, Structural Studies, Fluorescence and Optical Properties of Group VI Dinuclear Derivatives of N2O2 Schiff Base Aml A. A. Awad, Doaa A. Nassar * , Omyma A. M. Ali Chemistry Department, Faculty of Women for Arts, Science and Education, Ain Shams University, Cairo, Egypt. 1. INTRODUCTION Schiff bases metal complexes containing nitrogen and oxygen donor atoms play an important role in an enormous number of publications, ranging from pure synthetic work to physicochemical [1] and biochemically relevant studies of metal complexes [2]. They also use as photo-sensitizers, catalysts and conducting coordinating polymers [3,4,5] and found wide range of applications [6,7]. On the other hand, carbonyl complexes are useful intermediates in the synthesis of important coordination compounds [8,9,10]. In addition, metal carbonyl complexes are of considerable structural interest as well as of industrial, catalytical importance, epoxidation reactions, catalytic activity in hydrogenation of olefines and photochromic properties [11,12]. Schiff bases containing nitrogen and oxygen donor atoms such as bis-(salicylaldehyde)ethylenediimine (salenH2), bis (salicylaldehyde) phenylenediimine (salphenH2), salicylideneimine-2-anisole (salanH), N-salicylidene-2-hydroxyaniline (shaH2), 2,4-dichloro-5- Fluorophenyl and derivatives of benzimidazole, thiazole, pyridine, pyrazolone, hydrazine, p- fluorobezaldehyde are useful for the synthesis of transition metal complexes which play important role in biological systems [13,14,15,16,17,18]. Our interest in investigation of the reactions of metal carbonyls with Schiff bases has prompted us to investigate the reactions of M(CO)6 (M=Cr, Mo and W) with Schiff base (H2L) derived from 3,5- dichlorosalicylaldehyde and benzidine. 2. EXPERIMENTAL 2.1.Materials M(CO)6, M=Cr, Mo and W; 3,5-Dichlorosalicylaldehyde and benzidine were supplied from Aldrich. All the chemicals were of analytical reagent grade and used without purification 2.2. Instrumentation Carbon, hydrogen and nitrogen (C, H & N) analyses were carried out on a Perkin- Elmer 2400 mode instrument. IR spectra were recorded using KBr pellets in the region 4000-400 cm -1 on FTIR spectrophotometer, Shimadzu 8201. The 1 H NMR spectra was recorded by using DMSO as a solvent *Corresponding Author: Doaa A. Nassar, Chemistry Department, Faculty of Women for Arts, Science and Education, Ain Shams University, Cairo, Egypt. Abstract: 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 were investigated. Under Sunlight irradiation, dinuclear carbonyl chromium complex [Cr2(CO)2L2] and two dinuclear oxo complexes [Mo2O4L2] and [W2O4L2] were isolated. In air, the corresponding reaction with Mo(CO)6 produced the dinuclear carbonyl oxo complex [Mo2O5(CO)L]. H2O. All complexes were characterized by elemental analysis, IR, mass and 1 H NMR spectroscopy. Magnetic studies for [Mo2O4L2], [W2O4L2] and [Mo2O5(CO)L]. H2O complexes showed diamagnetic characteristics. TG-DTG study was done to track the thermal behavior of the complexes and the thermodynamic parameters were computed from the thermal data using Coats-Redfern and Horowitz–Metzger methods. The ultraviolet–vis spectra of the complexes in DMSO showed broad bands due to ligand-to-metal charge transfer. The fluorescence spectra of these complexes indicate the luminescence characteristics of the complexes. The values of optical band gap energy (Eg) of the synthesized complexes suggested that these compounds could be used as semiconductors. Keywords: Benzidine; Carbonyl; Complexes; Fluorescence; Optical Properties