Interactions between Pr(III) Sm(III) Cations

Interactions betwixt Pr(III) Sm(III) CationspH-metric study of substituted3,5-diaryl isoxazolines interlacinges in 70% Dioxane resolvent media .S.A.Thorat1,S.D.Thakur2ABSTRACT-The complex defining between Pr(III)Sm(III) metal ions and 3-(2-hydroxy-3-nitro-5-methylphenyl)-5-(2-phenylethenyl)isoxazolineHNMP2EIL1,3-(2-hydroxy-3-bromo-4-nitro-5-methyl)-5-(4-methoxyphenyl)isoxazolineHBNM4MIL2,3-(2-hydroxy-3-bromo-4-nitro-5-methyl)-5-(3-nitrophenyl)isoxazolineHBNM3NIL3 make water been studied at 0.1M Ionic peculiarity (260.1)oC in 70% Dioxane water mixture by Bjerrum system as adopted by Calvin Wilson .It is observed that Pr(III)Sm(III) metal ions form 11 12 complexes with ligand L1,L2L3.The data obtained were used to estimate comp ar the set of proton ligand constancy constant (pK) metal ligand stability constant (log K).From estimated data (pK log K),the effect of substituents were studied.Key lyric poem-Substituted 3,5-diarylisoxazoline,Dioxane-water mixture,stability c onstant.1.INTRODUCTION-The studies in metal ligand complexes in outcome of a number of metal ion with carboxylic acids, oximes, phenol etcetera Would be interesting which throw light on the mode of storage and transport of metal ions in biological Kingdom.Metal with the view to understand the bioinorganic chemistry of metal ions, Banergee et al1 have synthesized a no. of mixed ligand alkalic earth metal complexes. Bjerrums 2 dissertation has taken the initiative to develop field. Metal complexation not only brings the reacting molecules to rushher to give activated complex 3 but also polarized electrons from the ligand towards the metal. The relation between stability and basicity of ligands is indicated by the defining constant and free energy change value Bulkier group increases the basicity of ligands as well as stability. The stability of complexes is determined by the nature of central metal atom and ligands. Poddar et al 4 investigated stability constants of some substitu ted pyrazolines,isoxaline and diketone Karalmai et al 5 have studied formation constants and thermodynamic parameters of bivalent metal ion complexes with3-amino-5-ethyl isoxazole Schiff bases and N,NN,O and O,O donar ligands in solution.Recently Tihile 6 studies on interaction between cu (II), Cr(II), Nd(II) and Pr(II) metal ions and substituted hydroxyl chalcones at 0.1 M ionicstrength pH metrically. Thakur et al 7,8 have studies the influence of dielectric constants of medium on the complex equilibrium of substituted hydroxyl-1,3- propandiones with Cr(II) metal ions and studies on interaction between Cu(II), Cr(II) and Ni(II) metal ions at 0.1M ionic strength pH metrically. Isoxazolines posses medicinal activities such as anti-inflammatory9,antibacterial,anticonvulsant10,antibiotic11,antituberculer12, antifungal13and anxiolytic activity14.In present work an attempt has been made to study the interactions between Pr(III)Sm(III) Cations At 0.1 M Ionic Strength with Ligand at 0.1 io nic strength,pH metrically in 70% Dioxane-water mixture.2. MATERIALS AND METHODSThe ligands L1,L2,L3 was synthesized in the laboratory by known books method. The purity of these compounds exceeds 99.5% and structures were confirmed by NMR, IR and melting points. The stock solutions of the ligand was prepared by dissolving inevitable amount of ligand in a minimum hatful of dioxane subsequently diluted to final volume. Metal ion solution was prepared by dissolving metal nitrate (Sigma Aldrich) and standardized by EDTA titration method as discussed in literature . Carbonate free sodium hydroxide solution was prepared by dissolving the Analar pellets in deionised water and solution was standardized 22. The stock solution of percholric acid was prepared and used after normalization 23.2.1. MeasurementsAll measurements were carried out at (260.1) 0C. Systronic microprocessor based pH meter with magnetic stirrer and feature glaze over and calomel electrode assembly used for pH measur ements. The sensitivity of pH meter is 0.01 units. The instrument could read pH in the range 0.00 to 14.00 in the steps of 0.005. The pH meter was switched on half an hour earlier starting the titration for initial warm up of the instrument. It was calibrated before each titration with an aqueous standard caramel solution of pH 7.00 and 9.20 at (260.1) 0C prepared from a Qualigens buffer tablets. The hydrogen ion ingress was measured with combined glass electrode.2.2. ProcedureThe data-based procedure involved the titrations ofi. Free acid HClO4 (0.01 mol.dm-3)ii. Free acid HClO4 (0.01 mol.dm-3) and ligand (20 x 10-4 mol.dm-3)iii. Free acid HClO4 (0.01 mole dm-3) and ligand (20 x 10-4 mol.dm-3) and metal ion (4 x 10-4mol.dm-3) against standard carbonate free sodium hydroxide(0.15 mol.dm-3) solution using Calvin-Bjerrum and Calvin-Wilson pH titration techniques. The ionic strength of all the solutions were maintained constant by adding appropriate amount of NaClO4 solution. All ti trations were carried out in 70 percentages of Dioxane-water mixtures and reading were recorded for each 0.1 ml addition. The sprains of pH against volume of NaOH solution were plotted (fig 1-3). The Proton-Ligand constants were compute from pH values obtained from the titration bows using the Irvin-Rossotti method and MATLAB figurer program (Table 1) .3. RESULTS AND DISCUSSIONThe extent of deviation may be the dissociation of -OH group. 3-(2-hydroxy-3-nitro-5-methylphenyl)-5-(2-phenylethenyl)isoxazolineHNMP2EIL1,3-(2-hydroxy-3-bromo-4-nitro-5-methyl)-5-(4-methoxyphenyl)isoxazolineHBNM4MIL2,3-(2-hydroxy-3-bromo-4-nitro-5-methyl)-5-(3-nitrophenyl)isoxazolineHBNM3NIL3 may be considered as a monobasic acid having one replaceable H+ ion from phenolic -OH group and can be delineate asHL H+ + LThe titration data were used to construct the curves acid curve (A), acid + ligand curve (A+L) and acid + ligand + metal ion curve (A+L+M) between volume of NaOH against pH.The proton-ligand for mation number nA were calculated by Irving and Rossotti expression (Table1)Where denotes the number of dissociable protons, N is the concentration of sodium hydroxide(0.15 mol.dm-3), (V2-V1) is the measure of displacement of the ligand curve relative to acid curve, where V2 and V1 are the volume of alkali added to reach the same pH reading to get accurate values of (V2-V1) the titration curves were drawn on an enlarged scale E0 and TL0are the resultant concentration of perchloric acid and concentration of Ligand, respectively. V0 isthe initial volume of reaction mixture (50 cm3). Proton-Ligand stability constant pk values of Ligand were calculated by algebraical method point wise calculation and also, estimated from formation curves nA Vs pH (Half integral method) by noting pH at which nA = 0.5Bjerrum 1957 (Table 2).Metal-Ligand stability constants (log k) were determined by the half integral method by plotting Vs pL. The experimental values determined using expressionWhere N, E0 , Vo and V2have same significance as in equation (1), V3 is the volume of NaOH added in the metal ion titration to attain the given pH reading and TM0 (4 x 10-4 mol dm-3) is the concentration of metal ion in reaction mixture. The stability constants for various binary complexes have been calculated ( Table 3).3.1. Metal Ligand constancy Constant ( log K)It is observed that (Table3 a-c ) sufficiently large difference between log K1 logK2Values of Sm(III)for ligand L1 L2Pr(III) for ligand L3 indicates the stepwise formation of complex between metal ion and ligand except Pr(III)for ligand L1L2 Sm(III)for ligand L3. It showed that less difference between log K1 log K2 values indicates complexes are occurring simultaneously. The higher value of ratio(Log K1/ Log K2) forPr(III)- Ligand- L1 L3 Sm(III)-ligand-L2 complex indicates the more stable stepwise complex formation as compare to Sm(III) Ligand-L1 L3 Pr(III)-Ligand L2 complexes.3.2. Proton-Ligand stability constant (pK)-It is obs erved from titration curve in (fig.1,2,3)shows that the ligand curves starts deviating from free acid (HClO4) curves at pH 2.12,2.0,2.14 respectively. The extent of deviation s may be the dissociation of OH group completely.4. CONCLUSIONFrom the titration curve, it is observed that the release between (Acid + Ligand) curve (Acid+Ligand +Metal) Curve for all system of L1,L2,L3 started from pH=2.12 to 3.38, this indicate the commencement of complex formation. in addition change in color from yellow to brown in pH range from 3.35 to 10.07 during the titration showed the complex formation between Metal Ligand.Table no.1 Proton Ligand Formation number (A) at (260.1)0C and at ionic strength =0.1 moldm-3 NaClO4 in 70%Dioxane-Water mixture.a) System HBMP2EI(L1) PHV1V2V2 V1A4.424.705.075.145.215.425.636.006.146.216.286.356.376.426.496.706.847.007.357.427.567.708.008.358.428.568.709.009.359.703.25183.25193.27433.27433.27433.30003.33303.33303.33303.34133.34133.35723.35893.36603.36613.36 623.44963.45823.46623.46623.48673.48673.50003.50003.53303.53323.56603.63303.66603.76613.41173.45013.50303.50393.50603.53273.56593.56603.56603.60833.62933.65683.65893.68073.68893.69773.78243.79123.81593.81593.84643.85093.86703.86703.91123.91193.95024.03304.12274.24870.15990.19820.22870.22960.23170.23270.23290.23300.23300.26700.28800.29960.30000.31470.32280.33150.33280.33300.34970.34970.35970.36420.36700.36700.37820.37870.38420.40000.45670.48260.75970.70230.65660.65520.65200.65070.65040.65030.65030.59960.56810.55060.55020.52820.56080.50300.50180.50160.47670.47670.46190.45520.45120.45120.43490.43420.42600.40370.31920.2805b) System HBNM4MI(L2) PHV1V2V2 V1A3.353.373.563.704.004.354.374.424.495.075.145.215.425.636.006.146.216.286.356.376.426.496.636.847.007.357.427.567.708.008.358.428.568.709.009.359.499.639.709.849.9810.003.20213.20243.20383.20423.20833.24753.24823.25183.25193.27433.27433.27433.30003.33303.33303.33303.34133.34133.35723.35893.36603.36613.36623.44963.45823.46623.46623.48 673.48673.50003.50003.53303.53323.56603.63303.66603.66613.66623.66633.70033.76603.80003.28343.29623.32053.32153.32673.36713.37583.38483.38493.43323.43333.43333.46593.49953.49963.49973.50833.50863.52503.52953.53703.53713.53743.62133.62993.64743.65343.67423.68243.69743.69873.73283.75883.79273.88263.96603.99994.02404.03334.08304.16604.23300.08130.09380.11670.11730.11840.11960.12760.13300.13300.15890.15900.15900.16590.16650.16660.16670.16700.16730.16780.170600.17100.17100.17120.17170.17170.18120.18720.18750.19570.19740.19870.19980.22560.22670.24960.30000.33380.35780.36700.38270.40000.43300.87770.85590.82450.82310.82190.82030.80830.80020.80020.76140.76130.76130.75090.75030.75010.74990.74950.74900.74840.74420.74360.74350.74340.74300.74300.72880.71990.71960.70450.70430.70280.70140.66290.66140.62770.55270.50230.46660.44700.44510.41700.3723c) System HBNM3NI(L3) PHV1V2V2 V1A3.353.373.563.704.004.354.374.424.495.075.145.215.425.636.006.146.216.286.356.376.426.496.706.847.007.357.427.567.708. 008.358.428.568.709.009.359.709.8410.0010.3510.703.20213.20243.20383.20423.20833.24753.24823.25183.25193.27433.27433.27433.30003.33303.33303.33303.34133.34133.35723.35893.36603.36613.36623.44963.45823.46623.46623.48673.48673.50003.50003.53303.53323.56603.63303.66603.76613.79073.80003.90004.03303.26083.26383.27083.30423.32503.37553.37803.38183.38193.43213.43323.43333.46413.49823.49823.49913.50773.50823.52423.52593.53303.53323.53333.63333.65693.66653.68283.70333.70343.75033.75063.79223.79303.83283.89983.93294.06614.12484.16604.29884.53160.05870.06140.06700.10000.11670.12800.12980.13000.13000.15780.15890.15900.16410.16520.16520.16610.16640.16690.16700.16700.16700.16710.16710.18370.19870.20030.21660.21660.21670.25030.25060.25920.25980.26680.26680.26690.30000.33400.36600.39880.49860.91170.90780.89940.84990.82480.80610.80480.80470.80470.76300.76140.76120.75370.75220.75220.75200.75170.75070.74960.74960.74960.74930.74930.72430.70100.70030.67550.67570.67590.62560.62530.61260.61170.60390.6039 0.60370.55340.50240.45570.40810.2617Table 2 Proton Ligand Stability Constant pKSystem pKHalf integral methodPointwise calculation methodHNMP2EI (L1)HBNM4MI(L2)HBNM3NI(L3)7.00279.49399.84427.34879.26439.2987Table 3 Metal Ligand Stability Constant(Log K)a) HNMP2EI (L1)SystemLog K1Log K2Log K1-LogK2LogK1/LogK2Pr(III)Sm(III)6.58076.79263.84653.97882.73422.81381.71081.7071 b) HBNM4MI(L2)SystemLog K1Log K2LogK1-LogK2LogK1/LogK2Pr(III)Sm(III)9.47869.57477.73776.65631.74092.91841.22491.4384c) HBNM3NI(L3)SystemLog K1Log K2Log K1 LogK2LogK1/LogK2Pr(III)Sm(III)9.99909.76587.49117.48912.50792.27671.33471.3040