Research Journal of Chemical Sciences ______________________________________________ ISSN 2231-606X Vol. 3(9), 77-79, September (2013) Res. J. Chem. Sci. International Science Congress Association 77 Short Communication Effect of Dielectric constants of Dioxane-Water mixtures on Proton-Ligand Dissociation constants (pK) and formation Constants of Cu (II) complexes with 1, 3-Diphenyl Thiazines pH-metrically at 0.1M ionic strength Rathore M.M., Parhate V.V. and Rajput P.R. Department of Chemistry, Vidya Bharati Mahavidyalaya, C. K. Naidu road, Camp, Amravati, MS, INDIA Available online at: www.isca.in Received 2nd February 2013, revised 12th July 2013, accepted 14th September 2013Abstract The interactions between Cu(II) and nitro-phenyl thiazine(L), chlorodiphenyl-thiazine (L), chloro, 1,3.thiazine (L), 1,3 phenyl thiazine (L), and 1,3 diphenyl thiazine (L), have been investigated by pH-metric technique at 0.1M ionic strength and in different percentage of dioxone-water mixture with Cu(II)-1,3, diphenyl thiazine data obtained can be used to study the effect of dielectric constants on proton–ligand stability constant. It showed that Cu (II) forms 1:1 and 1:2 complexes with substituted thiazines. It could be also seen that pK and log k values are found to be increased with increasing the percentage of dioxane-water mixtures. Keywords: Substituted thiazine, Cu (II) metal ion and dioxane. IntroductionSubstituted thiazines are antibiotic drugs and good chelating agents due to presence of electron donor nitro, phenyl and chloro groups. A survey of literature reveals that metal-ligand stability constants of Aminoacids, Adific acid, sulphonic acid and salicylic and their derivatives have seen studied by many workers. Proton-ligand and metal-ligand stability constants of Lanthanide Metal ions with substituted Pyrazolines and Pyrazoles have been studied by Bansod Narwade etal3 have investigated the stability constants of Lanthanide metal ions with some substituted sulphonic acids spectrophotometrically. Sandawale and Narwade4 have studied the influence of dielectric constants of methanol-water mixtures on formation constants of Cu(II). Glycyl-Glycyl-Glycine peptide complexes. In a view of analytical applications and antibiotic drugs it is worthwhile to know the physico-chemical properties of metal ion complexes and effect of dielectric constants of solvents on stability constants. Therefore, the present work is undertaken to make of systematic study of Cu(II) complexes with substituted thiazines. Rare earth ions are used as probe in biochemistry of calcium. Birnhanm etal5 showed that lanthanide ion could substitute the calcium ion to produce active enzymine system. Use of unnatural diacting agents in biological system is reported by Narwade. The role of binary complexes in storage and transport for physiological activity of substances has been studied. The biological properties of transition metal ion complexes have been reported by Sharma etal. Material and MethodsExperimental: Standard solution of 0.2M NaOH, 1M.KNOand 0.1M.KNO were prepared by using A.R. grade reagents. The aqueous solution of 0.01M of Cu(II) was prepared in double distilled water and its concentration was checked by standard solution of EDTA(0.01M). The solutions of 1, 3 all above substituted thiazine is prepared in 70% dioxane-water mixture as a solvent. Calvin-Bjerrum Titration Process: Titrations are carried out in an inert atmosphere of nitrogen gas, in order to keep away CO and removal of dissolved oxygen. Three sets of titrations are performed as follows: i. Free acid titration nitric acid (1 x 10-1M), ii. Free acid nitric acid (1 x 10M) + ligand (20 x 10-4 M), iii. Free acid, nitric acid (1 x 10-1M) + ligand (20 x 10-4 M) + Metal ion Cu(II), (4 x 10-4 M). Above three sets were titrated against standard solution of 0.2M NaOH and 0.1M ionic strength was maintained constant by adding an appropriate amount of 1M KNO solution. Titrations were carried out by bubbling nitrogen gas for removal of dissolved oxygen gas. pH values were corrected by the use of Van-Vitart and Hass equation10. Metal-ligand Stability Constants (log k and log k): The deviation of (acid + ligand metal ion) curves from (acid + ligand) curves was found around pH 2.75 and increased continued for all the systems. This indicated the commencement of complex formation between ligand and metal ion before hydrolysis. The values (n) metal-ligand formation numbers were evaluated by the use of Irving-Rossetti’s expression". The values of log k for 1:1 complex and log k f or 1:2 complex were evaluated and presented in table 1. Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 3(9), 77-79, September (2013) Res. J. Chem. Sci. International Science Congress Association 78 The values of stability constant increased with increasing the percentage of dioxane-water mixture. Table 2 There is no an appreciable change in log k and log k values this may be due to fact of the effect of dixane –bulk solvent that indicates the formation of simultaneously complexes. The deviation between ligand curve and metal ion curve indicated the commentment of complex formation morever the change in colour during titration also indicated the formation of complex between metal ion and ligand. The Plots of pK/log k vs 1/D (D-Dielectric Constant) The plots between pK /log k and 1/D showed linear relationship. Water is recognized by all workers in solution field as being a unique structure having three dimensional like frame work. The dielectric constant of a medium is not solely responsible for the extent of dissociation. There is at least an additional factor for the chemical role of solvent in most cases. Table-1 Metal ligand stability constant between Cu(II) and substituted thiazines at 0.1m ionic strength S.N. System Log k Log 2 1 Nitrophenyl thiazine(L1) 5.15 4.85 2 Chloro diphenyl thiazine(L2) 5.05 4.65 3 Chloro 1,3 thiazine(L3) 5.25 4.95 4 1,3-phenil thiazine(L4) 4.95 4.75 5 1,3,diphenil thiazine(L5) 5.00 4.65 Results and DiscussionCalculation of Proton-ligand stability constant (pK). Existance of proton-ligand equilibria corresponds to dissociation of proton from -OH group of legand. HL= H+ + L- . The deviation between acid titration curve and legand titration curve showed to start the dissociation of -OH group of ligand. The average number of proton-associated with legand (n¯) were determined ¯from deviation employing using Irving-Rossotti's expression". Formation curves were obtained by plotting nA vs pH in different percentage of dioxane-water mixture and pK values were obtained at n = 0.5. The pK values were found to be increased with increasing the percentage of dioxane-water mixture. That may be due to the effect of bulky solvent12-14. ConclusionIt is also observed that from the above results are clearly indicates that the interaction of ligands with metal ions will directly affect the complex formation and due to that changes occur in log K values. It could be also seen that pK and log k values are found to be increased with increasing the percentage of dioxane-water mixtures. References1.Mane G.V., Kolhatkar D.G. and Shinde L.P., pH – Metric studies in binary and ternary complexes of dicarboxylic acids and amino acids with some transition and inner transition metal ions, Journal of Chemical and Pharmaceutical Research,4(2), 1022-1027 (2012) 2.Gharib F., Farajtabar A. and Bahmani F., Solvent effects on protonation constants of tryptophan in some aqueous aliphatic alcohol solutions, J. Chem. Eng. Data,55(1),327–332 (2010)3.Ramteke A.A. and Narwade M.L., Spectrophotometric Studies on stability constant of chlorosubstituted pyrazoles with Cu (II) Nd (III) and Tb (III) metal ions at 0.1 M Ionic strength, Der Chemica Sinica,3(4), 770-774, (2012)4.Meshram U.P., Narwade M.L. and Yaul A.R., Studies in formation constant of Al(III), Cr(III) and Fe(III) complexes with some substituted isoxazoline, pyrazole and pyrazoline pH-metrically, spectrophotometrycally and polarizibility constant refractometrically, J. Chem. Pharm. Res., 3(3), 77-82 (2011)5.Zaker Y.M., Hossain A. and IslamT.S.A., Adsorption kinetics of methylene blue onto clay fractionated from bijoypur soil, Bangladesh, Res. J. Chem. Sci., 3(2), 65-72 (2013)Table-2 The values of pK and log k in different percentage of dioxane-water mixture of Cu (II) - 1,3 diphenyl complex % Dioxane Dielectric Constant D 1/D Mole Fraction pK log k log k 50 34.26 0.02910 0.1735 5.75 4.65 4.55 55 30.10 0.03322 0.2041 6.50 4.70 4.60 60 25.85 0.03868 0.2395 7.15 4.85 4.65 65 21.80 0.04587 0.2805 7.75 4.95 4.72 70 17.69 0.05652 0.3288 8.00 5.15 4.85 75 14.4 0.06944 0.3864 8.50 5.30 4.93 Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 3(9), 77-79, September (2013) Res. J. Chem. Sci. International Science Congress Association 79 6.Hirpaye B.Y., Zekarias M.T. and Rao G.N., Chemical speciation studies of binary complexes of malonic acid with some essential biologically important metal ions in 1, 2-propanediol-water mixtures, Journal of Chemical and Pharmaceutical Research,4(3), 1725-1733 (2012)7.Raymond P., Peter P.R., Rajendran S. and Manivannan M., Investigation of corrosion inhibition of stainless steel by sodium tungstate patric, Res. J. Chem. Sci., 3(2), 54-58 (2013)8.Gaikwad M.N., Gaikwad S.T. and Rajbhoj A.S., Potentiometric study of menadione complexes with transition metals in DMSO-Water and DMF-Water medium, J. Chem. Bio. Phy. Sci. Sec., A2(4), 1651-1656 (2012)9. Zaida A.A., Farooquia M. and Janrao D.M., Study of stability constant of biological active molecules (drug) using potentiometric titration technique, J. Chem. Bio. Phy. Sci. Sec. A.,2(1), 67-81 (2012)10.Gangwar M.K. and Saxena A.K., Ultrasonic study of molecular interactions in binary mixtures of isopropylbenzene (Cumene) with Benzene, Toluene and Acetone at 303K, Res. J. Chem. Sci.,3(2), 27-30 (2013)11.Maldhure A.K., Agarkar S.S., Taywade R.K. and Wankhade R.S., Metal-ligand stability constants of Co(II), Ni(II) and Cu(II) metal ion complexes with N-(5-methyl-2-hydroxyacetophenone) - N’ - (2-hydroxyacetophenone)ethylenediamine at 0.1 M ionic strength pH metrically, Journal of Chemical and Pharmaceutical Research,4(8),3865-3868 (2012)12.Anderegg G., Delgado R., Felcman J., and Popov K., Critical evaluation of stability constants of metal complexes of complexones for biomedical and environmental applications, Pure Appl. Chem., 77(8),1445–1495 (2005)13.Patil S.S. and Mirgane S.R., Thermo acoustic study of acrylates with decane-1-ol, Res. J. Chem. Sci., 3(2), 73-78 (2013)14.Onigbinde A.O., Munson B. and Amos-Tautua B.M.W., Gas chromatography/ chemical ionization mass spectrometry of polyethylene glycol monoalkyl ethers,Res. J. Chem. Sci., 3(2), 4-9 (2013)