%0 Journal Article
%T Polydentate Schiff Base Ligands and Their La(III) Complexes: Synthesis, Characterization, Antibacterial, Thermal, and Electrochemical Properties
%A Ali E. £¿abik
%A Muharrem Karab£¿rk
%A G£¿khan Ceyhan
%A Mehmet T¨¹mer
%A Metin D£¿£¿rak
%J International Journal of Inorganic Chemistry
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/791219
%X We synthesized the Schiff base ligands H2L1¨CH2L4 and their La(III) complexes and characterized them by the analytical and spectroscopic methods. We investigated their electrochemical and antimicrobial activity properties. The electrochemical properties of the ligands H2L1¨CH2L4 and their La(III) complexes were studied at the different scan rates (100 and 200£¿mV), different pH ranges ( ), and in the different solvents. The electrooxidation of the Schiff base ligands involves a reversible transfer of two electrons and two protons in solutions of pH up to 5.5, in agreement with the one-step two-electron mechanism. In solutions of pH higher than 5.5, the process of electrooxidation reaction of the Schiff base ligands and their La(III) complexes follows an ECi mechanism. The antimicrobial activities of the ligands and their complexes were studied. The thermal properties of the metal complexes were studied under nitrogen atmosphere in the range of temperature 20¨C1000¡ãC. 1. Introduction Schiff bases were firstly synthesized by H. Schiff. Condensation of primary amines with carbonyl compounds yields Schiff bases [1, 2]. Schiff bases have been amongst the most widely studied coordination compounds and are becoming increasingly important as biochemical, analytical, and antimicrobial reagents [3]. Schiff bases derived from a large number of carbonyl compounds and amines have been used [4, 5]. The transition metal complexes having oxygen and nitrogen donor Schiff bases possess unusual configuration, structural liability, and are sensitive to the molecular environment [6]. Lanthanides or lanthanos form a largest series of periodic table. It is 4f inner transition series. Lanthanide (III) ions, because of their size, are the best ions form stable complexes with high coordination number [7, 8]. The number of Schiff base complexes of the lanthanide elements is similarly limited to a few reports [9]. A large number of compounds of the type M(N2O2), M(N2S2), M(N2), and M(N4) (using the binding atom representation) have been synthesized and characterized. These type complexes have been investigated because of their catalytic activity in oxygenation reactions [10], carrying out, for instance, the selective oxidation of organic substrates, such as olefins, alcohols, alkanes, and aldehydes, under mild conditions. This property may be very attractive [11], since the oxidation products can provide important starting materials for the production of fine chemicals and polymers [12, 13]. In addition, the oxidation of organic substrates mediated by high valent ruthenium oxo species
%U http://www.hindawi.com/journals/ijic/2012/791219/