ارائه ي روشي جديد براي محاسبه ي انرژي آزاد گيبس حلال پوشي يون هاي تك بار و ثابت اسيدي تركيبات مختلف در حلال هاي غيرآبي

چكيده انگليسي :

142 A New Method for Estimating the Solvation Gibbs Free Energy of Monovalent Ions and Acidity Constant of Some Compounds in Non aqueous Solvents Mohammad Manassir Email address m manassir@ch iut ac ir Date of submission Department of Chemistry Isfahan University of Technology Isfahan 84156 83111 Iran Supervisor Dr Hossein Farrokhpour h farrokh@cc iut ac ir Department Graduate Coordinator Alireza Najafi Chermahini Department of Chemistry Isfahan University of Technology Isfahan 84156 83111 IranAbstractIn the present work the free energy solvation of H Gsol was estimated in various important non Haqueous solvents including alcohols and polar aprotic solvents semi empirically The selectedsolvents were methanol ethanol 2 propanol 2 methyl 2 propanol dimethyle sulfoxide DMSO dimethyle formamid DMF and acetonitrile ACN The values of Gsol in 2 propanol and 2 H methyl 2 propanol were reported for the first time The estimated values of Gsol were used to Hpredict the acidity constants pKa of different compounds in the selected solvents These pKavalues have better agreement with the experimental values than the corresponding values obtained using the other Gsol reported in literature This confirmes that the values of Gsol predicted in this H Hwork are reasonable The calculated pKa values of selected compounds in non aqueous solventswere further corrected by accounting the error of the applied computational method for predictingthe pKa values of the compounds in water New correlation equations were proposed and used toestimate the pKa values of carboxylic acids aliphatic and aromatic derivatives phenol derivatives a series of active pharmaceutical ingredients and some anti inflammatory agents in the consideredsolvents when their experimental pKa values are known in water The calculations presented in thiswork were performed at four different levels of theory including B3LYP M062X MP2 and CCSDusing 6 311 G d p basis set separately The solvation Gibbs free energies SGFE of thirty nineions were estimated in protic and aprotic solvents including methanol ethanol N Ndimethylformamide DMF and acetonitrile ACN using a proposed approach In this method theerror of the applied computational method for estimating the SGFE of a specific ion in water anddimethyl solfoxide DMSO solvents was used as a reference value to correct the calculated SGFEof the ion in other protic and aprotic solvents respectively The predicted values of SGFE of ions obtained in this work show good agreement with those obtained using the other methods reportedin literature New correlation equations were also proposed which correlate the estimated values ofSGFE of ions in a specific solvent to the corresponding values in water and DMSO for protic andaprotic solvent respectively By using the proposed method in this work it is possible to estimatethe values of SGFE of ions in the solvents that there are no reports on them in literature providedthat the appropriate and correct reference solvent is selected Typically this method was applied ontwo most popular solvents in organic chemistry including acetone and 1 propanol to estimate theSGFE of the considered ions in them for the first time Keywords Acidity constant Solvation Gibbs Free Energy pharmaceutical Non aqueousSolvent Ion SMD DFT and Ab initio calculation

مناصير، محمد

ارائه ي روشي جديد براي محاسبه ي انرژي آزاد گيبس حلال پوشي يون هاي تك بار و ثابت اسيدي تركيبات مختلف در حلال هاي غيرآبي

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