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In continuation of our previous work here also, we have been interested in studying the stability of complexes of transition metals with biologically active ligands. Here we are presenting determination of stability constant of complex compounds using ligands synthesised from 5-Methyl furan-2-carbaldehyde and 7-methoxy naphthalene-2 -amine with bivalent transition metals i.e. Co(II), Ni(II), Cu(II) and Zn(II). Schiff's base ligands were synthesized by the condensation reaction of 5-Methyl furan-2-carbaldehyde with 7-Methoxy naphthalene -2 -amine. Nitrate salts of divalent cobalt, nickel, copper and zinc were estimated by standard volumetric and gravimetric methods. Ligand was analysed for elements by reported methods. pH metric titrations were carried out in an inert atmosphere of nitrogen gas at constant ionic strength of 0.1M KNO 3 with the help of digital pH meter.Stability constant of complexes of these metals with the ligands synthesized were computed by Irving-Rossoti technique 1 modified by Calvin Bjerrum 2 at temperatures 298K. The stability constant values of metals for the given ligand at the given temperature were found to be in the order Cu (II) > Ni(II), Co(II) > Zn (II). This result is in agreement with the natural order proposed by Irving-William. . A large number of such chelates have been synthesized, their structure and activity have been studied, but little is known about its stability in solution which will be its functioning condition. INTRODUCTION ExperimentalNitrate salts of divalent Co, Ni, Cu and Zn all were E. Merck. All other chemicals used were Anal R grade and used without further purification. Elemental analysis of metal salts were done by volumetric and gravimetric methods 11. Double distilled and deionised water was used throu778ghout the experiment. All titrations were done in aqueous-dioxane medium in the ratio 3:2 (v/v). Dioxane was purified by standard method.Schiff's base ligands were synthesised by reported method 12 1.5 g of 3-Methyl furan-2-carbaldehyde in solution were mixed with 3.5 g 7 -Hydroxy naphthalene -2 -amine. The mixture was refluxed in the presence of glacial acetic acid for 3 hours. The solution was concentrated and cooled to 0 0 C. The product obtained was filtered, washed several times and recrystallised from ethanol. The yield of product was nearly 2.40 g Solution of metal salts, ligands, electrolytes etc were prepared in doubly distilled CO 2 free water. Strength of various solutions used were tabulated in Table - A R T I C L E I N F O A B S T R A C TIn continuation of our previous work here also, we have been interested in studying the stability of complexes of transition metals with biologically active ligands.Here we are presenting determination of stability constant of complex compounds using ligands synthesised from 5-Methyl furan-2-carbaldehyde and 7-methoxy naphthalene-2 -amine with bivalent transition metals i.e. Co(II), Ni(II), Cu(II) and Zn(II). Schiff's base ligands were synthesized by the condensation reaction of 5-Methyl furan-2-carbaldehyde ...

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In this paper an attempt has been made to highlight the physicochemical study of methnolic extract of leaves of Tilkor carried out by soxhlet extraction process, phytochemical analysis of the extract, separations, isolation of bioactive components through Thin Layer Chromatography (TLC) as well as column chromatography respectively and characterisation of isolated compound by the means of several spectral analysis such as 1H NMR, 13C NMR, IR, U.V. Mass spectroscopy. The methanolic extract of leaves of the plant (in tropical conditions of Mithilanchal, Bihar, India) reveal the presence of phytochemicals like alkaloids, flavanoids, tannins, saponins, cardiac glycosides, steroids, terpenoids etc. The secondary metaboilities showed antimicrobial activity. The two isolated compounds were characterised by spectroscopic techniques which revealed the structure of compound A as - stigmosterol and compound B as tritriaconatane and is also found to have antimicrobial activity.

In continuation of the previous work here we are going to report stability constant values of transition metals like Cu(II) , Ni(II), Co(II) and Zn (II) with Schiff;s base ligand. Schiff's base ligands were synthesized by the condensation reaction of β-Naphthaldehyde with 7-Hydroxy naphthalene -2 -amine .Nitrate salts of divalent cobalt, nickel, copper and zinc were estimated by usual methods. Ligand was analysed for elements by standard method. pH metric titrations were carried out with the help of digital pH meter and stability constant of complexes of these metals with the ligands synthesized were computed by Irving-Rossotti technique modified by Calvin-Bjerrum. The stability constant values of metals for the given ligand were found to be in the order Cu(II) > Ni(II), Co(II) > Zn (II). This result is in agreement with the natural order proposed by Irving-William.