Effect of pH on the formation of complex compounds with Schiff ...

<strong>Effect</strong> <strong>of</strong> <strong>pH</strong>....B. M. Kalshetty et al.Pyruic acid Transuminase (SGPT) to normal condition, and it helps to restore the liver functioning byproviding multidimensional approach by showing anti-viral, anti-oxidant, anti-inflammatory, immunomodulatory,choleretic and anti-cholestatic activity 8 .The metal complexes are still a major line <strong>of</strong> approach to develop new drugs. It involves efforts to combinethe separate pharmacophoric groups <strong>of</strong> similar activity into one compound. Thus making structural changes inthe biological activity. As reported earlier the thiazolidine ring present in a large number <strong>of</strong> biologically activecompounds exhibiting different activities. The development <strong>of</strong> penicillin which shows the thiozoline ring.The present developments <strong>of</strong> 7-Amino-4-methyl coumarin compounds with metal ions are most fascinatingand useful areas in medical chemistry. The discovery <strong>of</strong> coumarin as therapeutic agents in 1820’s was thebeginning <strong>of</strong> the coumarin drug development. Due to the diversified nature <strong>of</strong> coumarin and is completely safewhich renders as useful substance in drug research.Keeping in view the above importance <strong>of</strong> 7-Amino-4methyl coumarin and the continuation <strong>of</strong> work on thesynthesis <strong>of</strong> Schiff base derived from 3-Aldehydosalicylic acid and its complex compounds with metal ionssuch as Cu (II), Zn (II), Ni (II), Co (II), and Cd (II) at different <strong>pH</strong>. The Schiff base compound (Scheme 1)synthesized followed by standard procedures 9,10 contains the acidic groups such as –COOH and –OH(phenolic), it is predicted that the coordination behavior <strong>of</strong> ligand would be developed on <strong>pH</strong> using differentreaction conditions and are remarkably different from those reported by Nag et al 11 .,COOHCH 3OHHCNOOScheme-1: Schiff base ligand (LH2) 2-hydroxy-3-((4-methyl-2-oxo-2H-chromen-7-ylimino)methyl)benzoic acidResults and DiscussionSchiff base ligands LH 2 (Scheme 1) was synthesized by the standard methods 9, 10 . It is dark yellow incolor; it is sparingly soluble in water, in aqueous sodium hydroxide solution. But, readily soluble in alcohol(owing to the possession <strong>of</strong> the phenolic and carboxylic groups).The synthesis <strong>of</strong> coordination compoundswith metal ions at various <strong>pH</strong> ranges reported as follows:(I) At <strong>pH</strong>= 3-4: An aqueous or water-ethanol solution <strong>of</strong> the ligand LH 2 (Scheme 1) reacts with metal ions in2:1 molar ratio forming metal complex compounds <strong>of</strong> the types [M(LH) 2 ] where M= Cu(II), Zn(II), Cd(II)(Scheme 2) and [M(LH) 2 (OH) 2 ] where M= Co(II), Ni(II) (Scheme 3). The formations <strong>of</strong> the complexcompounds at this <strong>pH</strong> range are shown below:MCl 2 (aq) + 2LH 2 (aq)[M (LH) 2 ] + 2 HCl...1Wher as M= Cu (II), Zn (II), Cd (II).andMCl 2 (aq) + 2LH 2 (aq) [M (LH) 2(H 2 O) 2 ]...2wher as M= Co (II), Ni (II).7J. Chem. Bio. Phy. Sci. Sec. A. Nov. 2011- Jan. 2012, Vol.2, N0.1, 6-13