%0 Journal Article
%T Synthesis and Characterization of New Lead(II) and Organotin(IV) Complexes of Schiff Bases Derived from Histidine and Methionine
%A Har Lal Singh
%A J. B. Singh
%J International Journal of Inorganic Chemistry
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/568797
%X New Schiff base (HL) ligand is prepared via condensation of isatins and amino acids in 1:1 molar ratio. Metal complexes are prepared and characterized by elemental analysis, molar conductance, electronic, infrared, and multinuclear magnetic resonance (1H NMR, 13C NMR, and 119Sn NMR). The analytical data showed that the ligand acts as bidentate toward metal ions via azomethine nitrogen and carboxylate oxygen by a stoichiometric reaction of metalˋ:ˋligand (1ˋ:ˋ2) to from metal complexes (Pb(II)(L)2 and Bu2Sn(L)2, where L is the Schiff base ligands of histidine and methionine). The conductivity values between 15 and 25 次ˋ1cm2ˋmolˋ1 in DMF imply the presence of nonelectrolyte species. On the basis of the above spectral studies, distorted octahedral and tetrahedral geometry have been proposed for the resulting organotin(IV) and lead(II) complexes. 1. Introduction Metal Schiff-base complexes have continued to play the role of one of the most important stereochemical models in main group and transition metal coordination chemistry due to their preparative accessibility, diversity, and structural variability. In recent years, a number of Schiff bases have been reported to possess significant and diverse biological activities such as antifungal, analgesic, anti-inflammatory, antibacterial, antioxidant, antitumor, local anesthetic, and antimicrobial activities [1每6]. On the other hand, radicals retard the progress of many chronic diseases such as vascular diseases, oxidative stress responsible for DNA, protein and membrane damage, and some forms of cancer [7, 8]. During the last few decades, metal carboxylates have been the subject of extensive investigations because of their remarkable structural diversity [9, 10] as well as significant biological activity, for example, pesticidal, bactericidal, and antitumor agents [11, 12]. In continuation of recent reports from this laboratory on some amino acid Schiff base metal complex systems [13每16], the present studies, ligand (L1H每L4H) is obtained by the condensation reaction between amino acids (L-histidine, DL-methionine) and isatin, chloroisatin with this hope that it may provide us valuable theoretical information for exploring metal-based bacteriostatic and carcinostatic pharmaceuticals with high efficacy and low toxicity. In this effort, we have also introduced an azomethine (每C=N每) linkage with the concern that it may permit a notable variety in the remarkable chemistry and behavior of such compounds. The synthesized Schiff base derived compounds (L1H每L4H) have been exposed to act as bidentate towards Pb(II) and
%U http://www.hindawi.com/journals/ijic/2012/568797/