title: Tetradentate Schiff base ligands and their complexes: synthesis, structural characterization, thermal, electrochemical and alkane oxidation.
abstract: Three Schiff base ligands (H(2)L(1)-H(2)L(3)) with N(2)O(2) donor sites were synthesized by condensation of 1,5-diaminonapthalene with benzaldehyde derivatives. A series of Cu(II), Co(II), Ni(II), Mn(II) and Cr(III) complexes were prepared and characterized by spectroscopic and analytical methods. Thermal, electrochemical and alkane oxidation reactions of the ligands and their metal complexes were investigated. Extensive application of 1D ((1)H, (13)C NMR) and 2D (COSY, HETCOR, HMBC and TOSCY) NMR techniques were used to characterize the structures of the ligands and establish the (1)H and (13)C resonance assignments of the three ligands. Ligands H(2)L(1) and H(2)L(3) were obtained as single crystals from THF solution and characterized by X-ray diffraction. Both molecules are centrosymmetric and asymmetric unit contains one half of the molecule. Catalytic alkane oxidation reactions with the transition metal complexes investigated using cyclohexane and cyclooctane as substrates. The Cu(II) and Cr(III) complexes showed good catalytic activity in the oxidation of cyclohexane and cyclooctane to desired oxidized products. Electrochemical and thermal properties of the compounds were also investigated.
authors.affiliation: Kahramanmaraş Sütçü Imam University, Chemistry Department, 46100 K. Maras, Turkey.
authors.forename: Gökhan
authors.initials: G
authors.lastname: Ceyhan
authors.forename: Muhammet
authors.initials: M
authors.lastname: Köse
authors.forename: Vickie
authors.initials: V
authors.lastname: McKee
authors.forename: Serhan
authors.initials: S
authors.lastname: Uruş
authors.forename: Ayşegül
authors.initials: A
authors.lastname: Gölcü
authors.forename: Mehmet
authors.initials: M
authors.lastname: Tümer
mesh_terms: D000042:Absorption; D000473:Alkanes / Q000737:chemistry*; D002384:Catalysis; D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003510:Cyclohexanes / Q000737:chemistry; D034242:Cyclooctanes / Q000737:chemistry; D055664:Electrochemical Techniques / Q000379:methods*; D004583:Electrons; D006860:Hydrogen Bonding; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008872:Microwaves; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D012545:Schiff Bases / Q000138:chemical synthesis* / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013696:Temperature
chemical_list: D000473:Alkanes; D056831:Coordination Complexes; D003510:Cyclohexanes; D034242:Cyclooctanes; D008024:Ligands; D012545:Schiff Bases; C506365:Cyclohexane; D006861:Hydrogen Peroxide; C474479:cyclooctane