International Journal of Chemistry Vol. 3, No. 1; February 2011

Transcription

1 International Journal of hemistry Vol., o. ; February Metric Studies of Interaction of Synthesized Ligands -amino--hydroxy--methylpyrimidine and -(-hydroxy--methylpyrimidino--phenylthiocarbamide with u(ii, d(ii, r(ii, ations t. M Ionic Strength Dipak T. Tayade Department of hemistry, S. R. R. Lahoti Science ollege Morshi, (MS, IDI Dinesh. Pund Department of hemistry, J. Darda college of Engee. & technology Yevatmal, (MS, IDI dinesh_pund@rediffmail.com Rahul. Bhagwatkar (orresponding author Department of hemistry, S. R. R. Lahoti Science ollege, Morshi, (MS, IDI Tel: bhagwatkar@gmail.com Dinesh B. Rathod Department of hemistry, S. S. K. Innani. Mv. Karanja Lad, (MS, IDI eha. Bhagwatkar Department of hemistry, Shivagi Science ollege, mravati, (MS, IDI bstract Guanidine was successfully interacted with acetoacetic ester to synthesize -amino--hydroxy--methylpyrimidine (L which on further treatment with phenylisothiocyanate furnishes -(-hydroxy--methylpyrimidino--phenylthiocarbamide (L. The interactions of u(ii, d(ii, r(ii metal ions with L and L have been studied at. M ionic strength in % Dioxane-water mixture by Bjerrum method as adopted by alvin and Wilson, It is observed that u(ii, d(ii, r(ii metal ions form : and : complexes with ligands (L and L. The data obtained were used to estimate and compare the values of proton-ligand stability constant (pk. and metal-ligand stability constants (log k.the effect of substituents were studied from estimated data (pk & log k. Keywords: Pyrimidines, Thiocarbamide, cetoacetic ester, Ionic strength, metry. Introduction Pyrimidino and thiocarbamido nucleus containing heterocycles possesses pharmaceutical, medicinal agricultural industrial and biotechnological significance(barnes, D. M., ; yril V., ; Ghaigy, ; Bossinger, ; Seidal,. Recently -amino--hydroxy--methylpyrimidine was successfully condensed with various isothiocyanates in acetone, ethanol, dioxane mediums to obtain -(-hydroxy--methylpyrimidino--substitutedthiocarbamides.(patil, When above reaction mixture was condensed in acetone-ethanol medium in : molar praportion the yield and purity increases with decrease in time span. ISS - E-ISS -

2 International Journal of hemistry Vol., o. ; February The manifold research work has been done on the study of metal and nitrogen heterocyclic ligands containing complexes(irving H, ; Martell,. Many workers have reported their results on metal-ligand stability constants. With the view to understand the bio-inorganic chemistry of metal ions, Banarjee et al ( have synthesized a number of mixed-ligand alkaline earth metal complexes. The studies of metal-ligand complexes in solution having number of metal ions with ligands carboxylic acids, oximes, phenols etc. would be interesting which throw a light on the mode of storage and transport of metal ions in biological kingdom. Bejerrum s ( dissertation describes the initiative to develop this field. Metal complexation not only brings the reacting molecules together to give activated complexes (Irving H, but also polarized electrons from the ligands towards the metal. The relation between stability and basicity of the ligands is indicated by the formation constant and free energy change value. Bulkier group increases the basicity of ligands as well as stability. The stability of the complexes is determined by the nature of central metal atom and ligand. The stability of complexes is influenced by the most important characteristics degree of oxidation, radius and electronic structure. Irving and Williams had studied the order of stability of metal complexes of transition metal ions by comparing the ionic radius and second ionization potentials of metal ions, as it is valid for most nitrogen and oxygen donor ligands. arwade et al ( have investigated metal-ligand stability constants of some lanthanides with some substituted sulphonic acids. Bodkhe et al ( have reported the metal-ligand stability constants of some β-dikctones. Tekade et al ( have investigated stability constants of some substituted pyrazolines, isoxalline and diketone. Prasad et al ( have studied mixed ligand complexes of alkaline earth metals, Mg(II. a(ii, Sr(II and Ba(II with -nitrosalicyladehyde and -diketones. Recently, Thakur et al ( studied the interaction between some lanthanide and radioactive metal ion with substituted Schiff s bases at. M ionic strength metrically and spectrophotometrically. In present work an attempt has been made to study the interactions between u(ii, d(ii, r(ii and -(-hydroxy--methylpyrimidino--substitutedthiocarbamide (L and L at. M ionic strength metrically in % dioxane-water mixture.. Materials and Methods ll the chemicals used were analar grade (India make alkyl/arylisothiocyanates were prepared according to the literature, melting points of all synthesized compounds were determined in open capillary and uncorrected. IR spectra were recorded on Perkin-Elmer spectrophotometer in the range - cm - in KBr pellets. PMR spectra were recorded with TMS as internal standard using Dl and DMSO. The purity of the compounds was checked on silica gel-g plates by TL.. Synthesis of -amino--hydroxy--methyl pyrimidine [L ] The interaction of guanidine with acetoacetic ester had been carried out in acetone-ethanol (:medium for eight hours in water bath. The precipitate was filtered. It was crystallized by precipitation method. (By precipitating it with acetic acid from its alkaline solution. Reaction yielded %, m.p. was. Product was off-white solid, soluble in hot acetone, benzene, hot ethanol and dioxane and insoluble in water and chloroform. When hot aqueous solution of the product was treated with aqueous ferric chloride (% gave red colouration, indicating the presence of phenolic - group. Desulphuration was noticed when the product was warmed with alkaline plumbite solution. It formed picrate (m.p.. The reaction scheme was shown in Scheme-I. The spectral data for IR (Table, H-MR (Table and HS-O analysis (Table was reported.. Synthesis of -(-hydroxy--methylpyrimidino--phenylthiocarbamide [L ] The interaction of -amino--hydroxy--methylpyrimidine with phenylisothiocyanates has been carried out in acetone-ethanol medium in : molar proportion in the boiling water bath for four hours, filter the reaction mixture to separate out -(-hydroxy--methylpyrimidino--phenylthiocarbamide [L ], washed several times with ml of water and crystallized with ethanol. Reaction yielded %, m.p. was. Product was brown solid, soluble in hot acetone, benzene, ethanol and dioxane and insoluble in water and chloroform. When hot aqueous solution of the product was treated with aqueous ferric chloride (% it gave red colouration, indicating the presence of phenolic - group. Desulphuration was noticed when the product was warmed with alkaline plumbite solution. It formed picrate (m.p.. The reaction scheme was shown in Scheme-II. The spectral data for IR (Table, H-MR (Table and HS-O analysis (Table was reported.. metric analysis Systronic microprocessor based instrument with accuracy in. unit with glass and saturated calomel electrode was used for the titrations. It was calibrated with the buffer solution of. and. at ±. before titrations. Titrations were carried out in an inert atmosphere by bubbling a constant flow of nitrogen gas. Published by anadian enter of Science and Education

3 International Journal of hemistry Vol., o. ; February The experimental procedure involved the titrations of i Free acid HlO (. M ii Free acid HlO (. M and ligand ( x - iii Free acid HlO (. M and ligand ( x - and metal ion ( x - M with standard a solution The ionic strength of all the solution was maintained constant (. M by adding appropriate amount of alo solution. ll the titrations were carried out in % dioxane-water mixture and the reading were recorded for each. ml addition. The graph of volume of alkali (a against were plotted (Fig. to Fig... Results and Discussion. Proton-ligand stability constants: The -(-hydroxy--methylpyrimidino--substitutedthiocarbamide was monobasic acids having only one dissociable H + ion from group. It can therefore, be represented as HL HL H + + L - The titration curves of the acid and ligand deviate at about.. The deviation between acid curves from ligand for all the systems showed the dissociation of H + ions from - groups of ligands. The proton-ligand formation number ( n were calculated by Irving and Rossotti expression. Where, V = Initial volume of solution ( ml E = Initial concentration of free acid (HlO T L = oncentration of ligand in ml solution = umber of dissociable protons from ligand = vagadros umber (V V = Volume of alkali (a consumed by acid and ligand on the same. The pk values were calculated from the formation curves between Vs n noting the at which n =. (half integral method and point wise calculations which are represented in Table. It is observed that, the order of pk values of ligands is found to be as, pk L > pk L. The reduction in pk values of L is attributed to the presence of electron withdrawing - group.. Metal-Ligand Stability onstants The stepwise formation constants of u(ii, d(ii, r(ii metal ions with ligands (L and L in % dioxane-water mixture were determined. The values of log K and log K were directly computed from the formation curve ( n Vs using half integral method. The most accurate values were calculated by point wise calculations which are presented in Table.. onclusion From the titration curves, it is observed that the departure between acid + ligand (+L curve and acid + ligand + metal (+L+M curve for all systems started from =.. This indicated the commencement of complex formation. lso change in colour from yellow to red in the range from to during titration showed the complex formation between metal and ligand. Observation of Table and shows that the less difference between log K and log K values indicates the complex formation between metal ion and ligand occurring simultaneously. The values of log K and log K (Table the stability of complexes was decided. For -amino--hydroxy--methylpyrimidine (L the difference between the values of log K and log K is higher with u(ii complex than d(ii and r(ii. It indicates that u(ii forms ISS - E-ISS -

4 International Journal of hemistry Vol., o. ; February more stable complex with Ligand- (L than d(ii and r(ii. nd for -(-hydroxy--methylpyrimidino--phenylthiocarbamide (L the difference between the values of log K and log K is higher with d(ii complex than u(ii and r(ii complexes. d(ii forms more stable complex with ligand than u(ii and r(ii metal ions. References Banarjee. K. and Rao T. V. R. (. J. Indian hem. Soc.,,. Barnes, D. M., Jianguo Ji, Fickes, M. G. (. J. m. hem. Soc.,, -. Bjerrum J. (. Metal amine formation in aqueous solutions, P. Haase and Sons, openhagen. Bodkhe P. S., Patil K.., arwade M. L. and Doshi,. G. (. isan J. hem., Vol., o. &, -. Bossinger,.D. and Tekeshi E. (. hem. bstr.,,. yril V., Milam, M. (. hem. bstr.,,. Florence. T. and ttwood D. (. Physical principle s of pharmacy, Macmillan. London. Fukuda V., Morishita R. and Sone K. (. Bull. hem. Sep. Jpn.,,. Ghaigy,. G. (. Siess Patent,,. Gudadhe S., arwade M. L. and Jamode V, S. (. cta. iencia. Indica (hem.,,. Irving H. and Rossotti H. (. J. hem. Soc.,. Irving H. and William R J. P. (. J. hem. Soc.,. Jansen J.. and Reedijk. J. (.. aturforsch. Teil B.,, (Eng.. Jolly V. S. rora G. D. and Taiwar P. (. J. Indian hem. Soc.,,. Kadu M. V. and Jamode V. S. (. sian, J. hem.,,. Martell. E. and alvin M. (. hemistry of metal chelate compounds. Prentice Hall. Inc. England. liffs.. J. arwade M. L. and Wankhade. S. (. J. Indian hem. Sot,,. arwade M. L., hincholkar M. M. and Sathe S. W. (. J. Indian hem. Soc.,,. atrajan. and Thormaraj P. (. Indian J. hem.,,. Patil S. U. (. Synthesis and studies on solute-solventinteraction of bromoacetophenones and coumaren--ones and their antimicrobialactivity. Ph. D. Thesis, mravati University, mravati. Patil, S. U., Raghuvanshi, P. B. (. sian J. hem., (, -. Pfeiffer. (. ngew ham.,,. Poddar S.., Dey K. and Poddar. G. (. Indian J. hem.,,. Prasad R.., grawal M., Ratnani R. and Sarswal K. (. J. Indian hemical Soc, Vol., PP.,. Rana. K. and Shah J. R. (. J. Indian hem. Soc.,,. Saha. Dalia M. and Sinha S. (. Indian J. hem.,,. Sawalakhe P. D. and arwade M. L. (. J. Indian hem. Soc.,,. Sawalakhe P.D. (. Studies in melal-ligand complexes with some substituted-.-diones and,-diarylpyrazole and pyrazoline. Ph. D. Thesis, mravati University, mravati. Schwarzenbach and nkerman. (. Helv. him. cta.,,. Seidal, M., Betiver, F. E., S. (. frican Patent,,,. Shuter Ya.. (. Zh. Obshch. Khim.,,. Tekade P. V., Patil K.., arwade M. L. (. cta iencia Indica., Vol. XXXI o.,. Thakur S. D., Munot K. P., Raghuvanshi P. B., Tayade D. T. (. cta iencia Indica, Vol. XXX o.,. Published by anadian enter of Science and Education

5 International Journal of hemistry Vol., o. ; February Table. IR spectra of synthesized compounds in (cm - ompound ν (-H ν (= ν(-= ν (>-O ν (>=S [(L ] [(L ]..... Table. H-MR spectra of synthesized compounds in (ppm ompound ( r- ( -H (r-h (pyrimidino-h ( -H [(L ] [(L ]..... Table. HS-O analysis of synthesized compounds in (ppm Table. ompound [(L ] [(L ] alculated (% Found (% alculated (% Found (% arbon.... Hydrogen.... itrogen.... Sulphur Ligands System Half internal Point wise method method L -amino--hydroxy--methylpyrimidine.. L -(-hydroxy--methylpyrimidino--phenylylthiocarbamide.. Table. Metal-ligand stability constants (log K System log K log K u(ii - ligand -.. d(ii - ligand -.. r(ii - ligand -.. u(ii - ligand -.. d(ii - ligand -.. r(ii - ligand -.. Table. Metal-ligand stability constants (log K System log K - log K log K / log K u(ii - ligand -.. d(ii - ligand -.. r(ii - ligand -.. u(ii - ligand -.. d(ii - ligand -.. r(ii - ligand -.. pk ISS - E-ISS -

6 International Journal of hemistry Vol., o. ; February Fig. Fig. Fig. SYSTEM - u(ii-(l SYSTEM - d(ii-(l SYSTEM - r(ii-(l +L +L+M +L +L+M Volum e of a (ml +L +L+M Fig. SYSTEM - u(ii-(l +L +L+M Fig. SYSTEM - d(ii-(l +L +L+M Fig. SYSTEM - r(ii-(l +L +L+M Where, - cid, L - Ligand, M - Metal H H H Guanidine + H H O cetoacetic ester H H cetone-ethanol : O H H (L -mino--hydroxy-- methylpyrimidine SHEME-I H H + S H (L -mino--hydroxy-- methylpyrimidine Phenylisothiocyanate Ethanol H H H (L S H -(-Hydroxy--methylpyrimidino- -phenylthiocarbamide SHEME-II Published by anadian enter of Science and Education