ChemInform Abstract: AN INTERPRETATION OF A GENERAL SCALE OF SOLVENT POLARITIES. A SIMPLIFIED REACTION FIELD THEORY MODIFICATION

1979 ◽  
Vol 10 (20) ◽  
Author(s):  
J.-L. M. ABBOUD ◽  
R. W. TAFT
Keyword(s):  
Field Theory ◽  
Reaction Field ◽  
General Scale

Simulation of volume polarization in reaction field theory

1999 ◽  
Vol 110 (16) ◽  
pp. 8012-8018 ◽  
Author(s):  
Daniel M. Chipman
Keyword(s):  
Field Theory ◽  
Reaction Field

Electrostatic effects on conformational equilibria: Solvation enthalpies and the reaction field theory

1984 ◽  
Vol 49 (9) ◽  
pp. 2050-2069 ◽  
Author(s):  
Zdeněk Friedl ◽  
Pavel Fiedler ◽  
Ján Biroš ◽  
Věra Uchytilová ◽  
Igor Tvaroška ◽  
...  
Keyword(s):  
Field Theory ◽  
Gas Phase ◽  
Quantum Chemical ◽  
Present Theory ◽  
Coulombic Interaction ◽  
Reaction Field ◽  
Considerable Uncertainty ◽  
Quantum Chemical Methods ◽  
Homogenous Medium ◽  
The Individual

Solvation enthalpies of isomeric methyl 2-, 3-, and 4-fluorobenzoates in solvents n-hexane and nitromethane were determined calorimetrically. The enthalpy of the conformational equilibrium ap ⇌ sp of methyl 2-fluorobenzoate was estimated from the temperature dependence of IR spectra and served to calculate the solvation enthalpies of the two conformers, although with a considerable uncertainty. All the results together were discussed in terms of two theories: a) the simple electrostatic approach predicting the reaction enthalphy from the coulombic interaction of atomic charges in an apparently homogenous medium, and b) the extended reaction-field theory expressing the solvation energy as a sum of dipole, quadrupole, cavity, and dispersion terms. In addition, quantum chemical calculations on various levels were carried out. Comparison with experiments revealed that the reaction-field theory, even if extended, reproduces only the general trend in the solvation enthalpies. Of the individual terms particularly the dispersion term is likely to be responsible for the bad fit: it is significant but cannot be satisfactorily predicted by the present theory. Also cavity term is mispresented by theory while it is in fact unimportant for isomeric molecules. The simple electrostatic approach predicts the reaction enthalpy in the gas phase relatively well, i.e. with a similar precision as semiempirical quantum chemical methods. In solvents this approach works worse, but still better than a two-step calculation consisting of the electrostatic gas-phase value and of the reaction-field solvation enthalpy; the latter procedure cannot be generally recommended. Summarizing, our results are in favour of simple theories which yield approximate results of the same quality as the more sophisticated ones, sometimes even better.

scholarly journals A Combined Synthetic and DFT Study on the Catalyst-Free and Solvent-Assisted Synthesis of 1,3,4-Oxadiazole-2-thiol Derivatives

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Mohammad Soleiman-Beigi ◽  
Reza Aryan ◽  
Maryam Yousofizadeh ◽  
Shima Khosravi
Keyword(s):  
Field Theory ◽  
Ab Initio ◽  
Solvent Effects ◽  
Reaction Medium ◽  
Theoretical Studies ◽  
Product Selectivity ◽  
Efficient Catalyst ◽  
Reaction Field ◽  
Effect Of Solvents ◽  
Catalyst Free

A novel practical and efficient catalyst-free method for the synthesis of 5-substituted 1,3,4-oxadiazole-2-thiols has been developed, which is assisted by reaction solvent (DMF). The solvent effects on product selectivity were studied based on Onsager’s reaction field theory of electrostatic solvation. The ab initio theoretical studies on the effect of solvents on the process also supported the suitability of DMF as the reaction medium for the preparation of 1,3,4-oxadiazole-2-thiol derivatives.

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