Sharif Digital Repository

Two series of the novel unsymmetrical diimino tetradentate Schiff bases derived from phenylenediamine and 1,3-naphthalene diamine and their vanadyl complexes were synthesized by template and non-template methods and characterized by 1H, 13C NMR, IR, UV-Vis and elemental analysis. These complexes are used as catalysts for the selective aerobic oxidation of cyclohexene. The catalytic activity increases as the number of electron-donor groups decreases, and the catalytic selectivity is varied by changing the substituents on the ligands. The catalytic system described here is an efficient and inexpensive method for the oxidation of olefins, with the advantages of high activity, selectivity,... 

Novel vanadyl Schiff base complexes with the general formula VOLx (x = 7-18) were synthesized and characterized by physicochemical methods. Only an orange polymeric form was obtained for VOL13, both brown polymeric and green monomeric forms were obtained for VOLx, x = 16, 17. These observations suggest that in these complexes oxovanadium(IV) exhibit a coordination number of five. Systematic substitution on the ancillary ligand have allowed V(V)/V(IV) reduction potentials to be tuned over a range of approximately 130mV. The complexes are catalysts for the aerobic oxidation of cyclohexene. Catalytic activity increases with increasing V(V)/V(IV) reduction potential and the catalytic selectivity... 

The novel N2O2 unsymmetrical tetradentate Schiff bases complexes are used as catalysts for the selective aerobic oxidation of cyclohexene. In general, conversion percentages decrease with increasing ΔEp and decreasing Eredox 0′. Catalytic activity increases with decrease of the number of electron-donating groups and the catalytic selectivity varies according to the types of substituents in the ligands. The catalytic system described here is an inexpensive method for selective oxidation of olefins, with advantages of high activity, selectivity, re-usability and short reaction times. Analysing GC and redox potential results shows a moderate correlation between selectivity and activity. © 2004...