%0 Journal Article
%T Synthesis, Characterization, and Electrochemical Behaviour of Cobalt(II) and Nickel(II) Complexes with Chelating Ligand 4,4¡ä-(Biphenyl-4,4¡ä-diyldinitrilo)dipentan-2-one
%A Lakhdar Sibous
%A Embarek Bentouhami
%A Mustayeen Ahmed Khan
%J Journal of Inorganic Chemistry
%D 2013
%R 10.1155/2013/104979
%X 4,4¡ä-Diaminobiphenyl reacts with 2,4-pentanedione in absolute ethanol in a molar ratio 1£¿:£¿2 to form mainly the product of [1 + 2] condensation, 4,4¡ä-(biphenyl-4,4¡ä-diyldinitrilo)dipentan-2-one (H2L). The Schiff base was used as tetradentate chelating ligand to coordinate and chlorides leading to complexes where the ratio of metal ligand was found to be 2£¿:£¿1 or 2£¿:£¿2. All the synthesized products were characterized by elemental analysis, infrared, electronic, and mass spectroscopy, 1H NMR, and DSC. The electrochemical behaviour of the ligand and its complexes in DMF is also investigated. 1. Introduction Aromatic Schiff base compounds have significant importance in the fields of coordination chemistry and material sciences because they are potentially capable to form stable complexes with different metal ions [1¨C3]. Schiff base ligands that have solvent dependent UV-vis spectra (solvatochromicity) can be suitable nonlinear optical (NLO) active materials [4]. They can be useful materials in solid phase extraction and synthesis of ion-selective electrodes for the determination of anions in analytical samples [5¨C7]. Schiff base ligands can also be used in enantioselective [8] and regioselective [9] ring opening of epoxides, enantioselective epoxidation of alkenes [10], and asymmetric oxidation of methyl phenyl sulphide [11]. Transition metal complexes with oxygen and nitrogen donor Schiff base ligands are of particular interest [12] because of their ability to possess unusual configuration, being structurally labile and their sensitivity to molecular environment [13]. Schiff base ligands can accommodate different metal centres involving various coordination modes thereby allowing successful synthesis of homo- and heterometallic complexes with varied stereochemistry [14]. This feature is employed for modelling active sites in biological systems [15]. Additionally, these complexes have wide applications such as antibacterial and antifungal agents [16]. Recently, much research on macrocyclic complexes have been focused on species containing the first-row transition metal ions and tetradentate ligands [17]. The formation of macrocyclic complexes depends significantly on the dimension of internal cavity, on the rigidity of the macrocycles, on the nature of its donor atoms, and on the complexing properties of the anion involved in the coordination [18]. The interest in such species stems from the application of these complexes ranging from modelling the active sites of many metalloenzymes [19] to hosting and carrying small molecules [20] or catalysts [21, 22].
%U http://www.hindawi.com/journals/jic/2013/104979/