title: Complexes of cis-dioxomolybdenum(VI) and oxovanadium(IV) with a tridentate ONS donor ligand: synthesis, spectroscopic properties, X-ray crystal structure and catalytic activity.
abstract: New cis-dioxomolybdenum(VI) and oxovanadium(IV) complexes of the Schiff base, derived from S-methyl dithiocarbazate and 2,3-dihydroxybenzaldehyde (H2dhsm), have been synthesized. The complexes of the type cis-[MoO2(dhsm)] (1a), cis-[MoO2(dhsm)(D)] (1b-1d) [D=neutral monodentate ligand; EtOH, pyridine (py) or imidazole (imz)], [VO(dhsm)(NN)] (2a, 2b) [NN=2,2'-bipyridine (bipy) or 1,10-phenanthroline (phen)] and [VO(dhsm)] (2c) have been isolated, characterized by (1)H NMR, IR, UV-Vis and EPR spectral studies and investigated by cyclic voltammetry. The X-ray crystal structure of cis-[MoO2(dhsm)(EtOH)] (1b) has been determined and shows that the complex has a distorted octahedral geometry in which the H2dhsm behaves as a dianionic ONS tridentate ligand coordinating via phenoxide oxygen, hydrazinic nitrogen and thiolate sulfur. The oxomolybdenum(IV) complex [MoO(dhsm)] (1e) has obtained from dioxomolybdenum(VI) complex (1b) by oxo abstraction with PPh3. The reactivity of the complexes toward catalytic oxidation of alcohols in the presence of H2O2 and t-BuOOH as co-oxidants under solvent free conditions is reported.
authors.affiliation: Department of Chemistry, Faculty of Science, Damietta University, Damietta, Egypt.
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: Fayed
authors.affiliation: Department of Chemistry, Faculty of Science, Damietta University, Damietta, Egypt.
authors.forename: Shadia A
authors.initials: SA
authors.lastname: Elsayed
authors.affiliation: Department of Chemistry, Faculty of Science, Damietta University, Damietta, Egypt. Electronic address: amelhendawy@yahoo.com.
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: El-Hendawy
authors.affiliation: Department of Chemistry, Faculty of Science, Damietta University, Damietta, Egypt.
authors.forename: Mohamed R
authors.initials: MR
authors.lastname: Mostafa
mesh_terms: D015082:2,2'-Dipyridyl / Q000138:chemical synthesis / Q000737:chemistry; D001547:Benzaldehydes / Q000138:chemical synthesis / Q000737:chemistry; D002384:Catalysis; D002396:Catechols / Q000138:chemical synthesis / Q000737:chemistry; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D007093:Imidazoles / Q000138:chemical synthesis / Q000737:chemistry; D008024:Ligands; D008958:Models, Molecular; D008982:Molybdenum / Q000737:chemistry*; D016877:Oxidants / Q000138:chemical synthesis / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000138:chemical synthesis / Q000737:chemistry*; D010618:Phenanthrolines / Q000138:chemical synthesis / Q000737:chemistry; D011725:Pyridines / Q000138:chemical synthesis / Q000737:chemistry; D012545:Schiff Bases / Q000138:chemical synthesis / Q000737:chemistry; D013057:Spectrum Analysis; D014638:Vanadates / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D001547:Benzaldehydes; D002396:Catechols; D056831:Coordination Complexes; D007093:Imidazoles; D008024:Ligands; D016877:Oxidants; D010087:Oxides; D010618:Phenanthrolines; D011725:Pyridines; D012545:Schiff Bases; C539565:molybdenum dioxide; C075743:oxovanadium IV; C067077:2,3-dihydroxybenzaldehyde; D014638:Vanadates; D015082:2,2'-Dipyridyl; C029899:imidazole; D008982:Molybdenum; C023666:pyridine; C025205:1,10-phenanthroline
keywords: Catalytic oxidations; Dioxomolybdenum(VI) complexes; ONS-donor ligand; Oxovanadium(IV) complexes; X-ray crystal structure