%0 Journal Article
%T Cobalt(II) and Manganese(II) Complexes of Novel Schiff Bases, Synthesis, Charcterization, and Thermal, Antimicrobial, Electronic, and Catalytic Features
%A Selma Bal
%A Sedat Salih Bal
%J Advances in Chemistry
%D 2014
%R 10.1155/2014/506851
%X Carbazoles containing two new Schiff bases (Z,Z)-N,N¡ä-bis[(9-ethyl-9H-carbazole-3-yl)methylene]propane-1,3 diamine (L1) and (Z,Z)-N,N¡ä-bis[(9-ethyl-9H-carbazole-3-yl)methylene]-2,2-dimethylpropane-1,3-diamine (L2) and their Co(II) and Mn(II) complexes were synthesized and characterized using various spectroscopic methods and thermal analysis, which gave high thermal stability results for the ligands and their cobalt complexes. The title compounds were examined for their antimicrobial and antifungal activities, which resulted in high activity values for the ligands and their manganese complexes. Oxidation reactions carried out on styrene and cyclohexene revealed that the complex compounds were the most effective catalysts for styrene oxidation, giving good selectivities than those of cyclohexene oxidation. Electronic features of the synthesized compounds were also reported within this work. 1. Introduction Schiff bases and their complexes have been and are being employed to many reactions in synthetic chemistry. In particular, the oxidation of alkenes is important intermediate to get new, industrially important chemicals for both organic synthesis and pharmaceutical industry. Catalytic transformations of hydrocarbons into valuable oxygenated derivatives such as alcohols, aldehydes, and epoxides using peroxides as oxidants have been extensively studied over the last few decades [1¨C5]. In particular, the catalysis of alkene oxidation by soluble transition metal complexes is of great interest in both biomimetic chemistry and synthetic chemistry [6]. So far various Schiff base complexes have been employed to catalytic oxidation of olefins to epoxides and aldehydes, and it has been proved that many Schiff base complexes gave improved results as catalysts for these kinds of oxidation reactions [7¨C20]. In our research, the synthesized Schiff base complexes have been searched for their potential use as catalysts in oxidation reactions for both cyclohexene and styrene. Not only for these oxidation reactions but also for many kinds, it is important to use eco-friendly with easy recoverability oxidants such as H2O2 and air. It is also important that the catalysts are thermally stable enough to carry out these kinds of reactions which generally require elevated temperatures [21, 22]. In addition their catalytic activities, various Schiff bases have also been examined for their biological activities in many previous studies [23¨C25]. This interest comes from the fact that their metal complexes can be used as antimicrobial, antifungal, and antitumor agents [26¨C28]. In
%U http://www.hindawi.com/journals/ac/2014/506851/