scholarly journals The influence of the solvent on organic reactivity. Part II. Hydroxylic solvent effects on the reaction rates of diazodiphenylmethane with 2-(2-substituted cyclohex-1-enyl)acetic and 2-(2-substituted

2004 ◽  
Vol 69 (8-9) ◽  
pp. 601-610 ◽  
Author(s):  
Jasmina Nikolic ◽  
Gordana Uscumlic ◽  
Vera Krstic
Keyword(s):  
Hydrogen Bond ◽  
Solvent Effects ◽  
Linear Regression Analysis ◽  
Solvent Polarity ◽  
Multiple Linear Regression Analysis ◽  
Reaction Rates ◽  
Hydrogen Bond Donor ◽  
Initial State ◽  
Hydrogen Bond Acceptor ◽  
Acetic Acids

The rate constants for the reaction of diazodiphenylmethane with 2-(2-substituted cyclohex-1-enyl)acetic acids and 2-(2-substituted phenyl)acetic acids, previously determined in seven hydroxylic solvents, were correlated using the total solvatochromic equation, of the form logk = logk0 + s?*+ a? + b?, the two-parameter model, logk=logk0 + s?*+ a? and a single parameter model logk = logk0 + b?, where ?*is a measure of the solvent polarity, ? represents the scale of solvent hydrogen bond acceptor basicities and ? represents the scale of solvent hydrogen bond donor acidities. The correlations of the kinetic data were carried out by means of multiple linear regression analysis and the solvent effects on the reaction rates were analyzed in terms of initial state and transition state contributions.

scholarly journals The kinetics of the reactions of 2-substituted nicotinic acids with diazodiphenylmethane in various alcohols

2003 ◽  
Vol 68 (7) ◽  
pp. 515-524 ◽  
Author(s):  
Sasa Drmanic ◽  
Bratislav Jovanovic ◽  
Aleksandar Marinkovic ◽  
Milica Misic-Vukovic
Keyword(s):  
Hydrogen Bond ◽  
Rate Constants ◽  
Linear Regression Analysis ◽  
Solvent Polarity ◽  
Multiple Linear Regression Analysis ◽  
Hydrogen Bond Donor ◽  
Initial State ◽  
Experimental Conditions ◽  
Hydrogen Bond Acceptor ◽  
Reaction Rate Constants

The rate constants of 2-substituted nicotinic acids in reaction with diazodiphenylmethane (DDM) in eight alcohols at 30 ?C have been determined. In order to explain the obtained results through solvent effects, the second order reaction rate constants (k) of the examined acids were correlated using the appropriate solvent parameters by the equation: logk=logk0 af(?) + b?* + cn?H where f(?) is the measure of solvent ability as a dielectric to stabilize the separation of opposite charges in the activated complex, ?* is the measure of solvent ability to stabilize proton in the initial state and n?H represents the ability of protic solvents to form hydrogen bond with the negative end of the ion-pair intermediate. These constants were correlated also by using solvatochromic equation of the form logk=logk0 + s?* + a? + b? where ?* is the measure of the solvent polarity, ? represents the scale of the solvent hydrogen bond donor acidities (HBD) and ? represents the scale of the solvent hydrogen bond acceptor basicities (HBA). The correlations of the kinetic data were carried out by means of multiple linear regression analysis. The results obtained for 2-substituted nicotinic acids were compared with the results for ortho-substituted benzoic acid under the same experimental conditions.

scholarly journals The reactivity of α,β-unsaturated carboxylic acids. Part XVI. The kinetics of the reaction of cycloalkenecarboxylic and cycloalkenylacetic acids with diazodiphenylmethane in various alcohols

2002 ◽  
Vol 67 (2) ◽  
pp. 77-85 ◽  
Author(s):  
Gordana Uscumlic ◽  
Jasmina Nikolic ◽  
Vera Krstic
Keyword(s):  
Hydrogen Bond ◽  
Rate Constants ◽  
Kinetic Data ◽  
Linear Regression Analysis ◽  
Spectroscopic Method ◽  
Solvent Polarity ◽  
Multiple Linear Regression Analysis ◽  
Hydrogen Bond Donor ◽  
Experimental Conditions ◽  
Hydrogen Bond Acceptor

The rate constants for the reaction of diazodiphenylmethane with 1-cyclopentenecarboxylic, 1-cycloheptenecarboxylic, cyclopent-1-enylacetic and cyclohept-1-enylacetic acids were determined in eight alcohols at 30 ?C using the appropriate UV-spectroscopic method. In order to explain the kinetic results through solvent effects, the second order rate constants of the examined acids were correlated using a total solvatochromic equation, of the form: log k = A0+ s?*+a??+ b?, where ?* is a measure of the solvent polarity, ??represents the scale of solvent hydrogen bond acceptor basicities and ? represents the scale of solvent hydrogen bond donor acidities. The correlations of the kinetic data were carried out by means of multiple linear regression analysis. The opposite sings of the electrophilic and the nucleophilic parameters are in agreement with the well-known reaction mechanism. The results presented in this paper were compared with the kinetic data for 1-cyclohexenecarboxylic and cyclohex-1-enylacetic acids obtained under the same experimental conditions.

scholarly journals Solvent effect on electronic absorption spectra of cyclohex-1-enylcarboxylic and 2-methylcyclohex-1-enylcarboxylic acids

2000 ◽  
Vol 65 (5-6) ◽  
pp. 353-359 ◽  
Author(s):  
Jasmina Nikolic ◽  
Gordana Uscumlic ◽  
Vera Krstic
Keyword(s):  
Hydrogen Bond ◽  
Absorption Spectra ◽  
Electronic Absorption Spectra ◽  
Linear Regression Analysis ◽  
Solvent Polarity ◽  
Multiple Linear Regression Analysis ◽  
Ultraviolet Absorption ◽  
Aprotic Solvents ◽  
Hydrogen Bond Donor ◽  
Hydrogen Bond Acceptor

The ultraviolet absorption spectra of cyclohex-1-enylcarboxylic acid and 2- methylcyclohex-1-enylcarboxylic acid were determined in six protic and nine aprotic solvents in the wavelength range from 200 to 400 nm. The position of the ?max of the two examined acids showed that the ultraviolet absorption maximums of cyclohex-1-enylcarboxylic acid were at consistently longer wavelengths in protic solvents than those of methylcyclohex-1-enylcarboxylic acid. The opposite was true in aprotic solvents. In order to explain the obtained results, the ultraviolet absorption frequencies of the electronic transitions in the carboxy carbonyl group of the examined acids were correlated using a total solvatochromic equation of the form: v = v0 + s?* + a? + b?, where ?* is a measure of the solvent polarity, ? represents the scale of solvent hydrogen bond acceptor basicities and a represents the scale of solvent hydrogen bond donor acidities. The correlation of the spectroscopic data was carried out by means of multiple linear regression analysis. The opposing solvent effects on the ultraviolet absorption maximums of the two examined acids were discussed.

scholarly journals Solvent effect on electronic absorption spectra of some 2-aminobenzimidazoles

2002 ◽  
pp. 93-99
Author(s):  
Nada Perusic-Janjic ◽  
Jevrem Janjic ◽  
Sanja Podunavac-Kuzmanovic
Keyword(s):  
Hydrogen Bond ◽  
Electronic Absorption Spectra ◽  
Linear Regression Analysis ◽  
Solvent Polarity ◽  
Multiple Linear Regression Analysis ◽  
Proton Donor ◽  
Proton Acceptor ◽  
Aprotic Solvents ◽  
Hydrogen Bond Donor ◽  
Hydrogen Bond Acceptor

The effect of protic and aprotic solvents on electronic apsorption spectra of 1-(3-X-benzil)-2-aminobenzimidazoles (X=CH3;OCH3; Cl) was examined. UV-apsorption spectra (200-400 nm) were recorded in five protic and four aprotic solvents. Batochromic shift of absorption maxima, ?max, occurs from the solvent with the highest proton-donor ability to the proton acceptor solvent (from water to DMSO). Positions of absortion maxima in various solvents are in correlation with the dielectric constant of the solvent. In order to explain the obtained results, the ultraviolet absorption frequences of the electronic transitions of the compounds were correlated using a total solvatochromic equation of the form: ?max = ?0 + s?* + a? + b?, where??* is the measure of solvent polarity. Prepresents the scale of solvent hydrogen bond acceptor basicities and ? represents the scale of solvent hydrogen bond donor acidities. Correlation of spectroscopic data was carried out by means of multiple linear regression analysis.

scholarly journals The comparative study of linear solvatation energy relationship for the reactivity of pyridine carboxylic acids with diazodiphenylmethane in protic and aprotic solvents

2012 ◽  
Vol 77 (10) ◽  
pp. 1311-1338 ◽  
Author(s):  
Sasa Drmanic ◽  
Jasmina Nikolic ◽  
Aleksandar Marinkovic ◽  
Bratislav Jovanovic
Keyword(s):  
Solvent Effects ◽  
Kinetic Data ◽  
Aprotic Solvent ◽  
Isonicotinic Acid ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Reaction Rates ◽  
Aprotic Solvents ◽  
Pyridine Carboxylic ◽  
The Comparative Study

Protic and aprotic solvent effects on the reactivity of picolinic, nicotinic and isonicotinic acid, as well as of some substituted nicotinic acids with diazodiphenylmethane (DDM) were investigated. In order to explain the kinetic results through solvent effects, the second-order rate constants for the reaction of the examined acids with DDM were correlated using the Kamlet-Taft solvatochromic equation. The correlations of the kinetic data were carried out by means of the multiple linear regression analysis and the solvent effects on the reaction rates were analyzed in terms of the contributions of the initial and the transition state. The signs of the equation coefficients support the already known reaction mechanism. The solvatation models for all the investigated acids are suggested and related to their specific structure.

scholarly journals Reactivity of cyclohex-1-enylcarboxylic and 2-methylcyclohex-1-enylcarboxylic acids with diazodiphenylmethane in aprotic solvents

2000 ◽  
Vol 65 (12) ◽  
pp. 839-846
Author(s):  
Jasmina Nikolic ◽  
Gordana Uscumlic ◽  
Vera Krstic
Keyword(s):  
Hydrogen Bond ◽  
Rate Constants ◽  
Kinetic Data ◽  
Linear Regression Analysis ◽  
Spectroscopic Method ◽  
Reaction Rates ◽  
Aprotic Solvents ◽  
Experimental Conditions ◽  
Hydrogen Bond Acceptor ◽  
Protic Solvents

Rate constants for the reaction of diazodiphenylmethane with cyclohex-1-enylcarboxylic acid and 2-methylcyclohex-1-enylcarboxylic acid were determined in nine aprotic solvents, as well as in seven protic solvents, at 30?C using the appropriate UV-spectroscopic method. In protic solvents the unsubsituted acid displayed higher reaction rates than the methyl-substituted one. The results in aprotic solvents showed quite the opposite, and the reaction rates were considerably lower. In order to explain the obtained results through solvent effects, reaction rate constants (k) of the examined acids were correlated using the total solvatochromic equation of the form: log k=logk0+s?*+a?+b?, where ?* is the measure of the solvent polarity, a represents the scale of the solvent hydrogen bond donor acidities (HBD) and b represents the scale of the solvent hydrogen bond acceptor basicities (HBA). The correlation of the kinetic data were carried out by means of multiple linear regression analysis and the opposite effects of aprotic solvents, as well as the difference in the influence of protic and aprotic solvents on the reaction of the two examined acids with DDM were discussed. The results presented in this paper for cyclohex-1-enylcarboxylic and 2-methylcyclohex-1-enylcarboxylic acids were compared with the kinetic data for benzoic acid obtained in the same chemical reaction, under the same experimental conditions.

Solvent effects in organic chemistry — recent developments

1988 ◽  
Vol 66 (11) ◽  
pp. 2673-2686 ◽  
Author(s):  
Michael H. Abraham ◽  
Priscilla L. Grellier ◽  
Jose-Luis M. Abboud ◽  
Ruth M. Doherty ◽  
Robert W. Taft
Keyword(s):  
Organic Chemistry ◽  
Solvent Effects ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Reaction Rates ◽  
Distribution Coefficients ◽  
Solvent Interactions ◽  
Conformational Equilibria ◽  
Recent Developments ◽  
Solubility Of Gases

Solvent effects on a number of different processes have been surveyed, and results of the application of multiple linear regression analysis are discussed. The processes examined include examples of solubility of gases or vapours, distribution coefficients of solutes between water and a series of solvents, and solvent effects on conformational equilibria, on keto–enol tautomerism, and on reaction rates. It is shown that two particular equations, that due to Koppel and Palm and extended by Makitra and Pirig, and that due to Abraham, Kamlet, and Taft, can cope quite satisfactorily with solvent effects on these various processes. It is pointed out that interpretation of parameters obtained from equations that involve macroscopic quantities such as ΔG≠ or ΔG0 is not necessarily straightforward, and that some model is needed in order to interpret these macroscopic quantities in terms of microscopic quantities that can characterise, for example, solute–solvent interactions.

scholarly journals Synthesis and investigation of solvent effects on the ultraviolet absorption spectra of 1, 3-bis-substituted-5, 5-dimethylhydantoins

2003 ◽  
Vol 68 (10) ◽  
pp. 699-706 ◽  
Author(s):  
Gordana Uscumlic ◽  
Abdulbaseta Kshad ◽  
Dusan Mijin
Keyword(s):  
Hydrogen Bond ◽  
Absorption Spectra ◽  
Electronic Absorption Spectra ◽  
Alkyl Halide ◽  
Substituent Effects ◽  
Solvent Polarity ◽  
Hydrogen Bond Donor ◽  
Hydrogen Bond Acceptor ◽  
Isolation Techniques ◽  
Energy Relationships

A series of 1,3-bis-substituted-5,5-dimethylhydantoins was synthesized using the reaction of 5,5-dimethylhydantoin with the corresponding alkyl halide in the presence of trimethylamine as catalyst and sodium hydroxide, according to a modified literature procedure. The experimental investigation included modification of the synthetic procedure in terms of starting materials solvent, temperature, isolation techniques, as well as purification and identification of the products. The absorption spectra of the 1,3-bis-substituted-5,5-dimethylhydantoins were recorded in twelve solvents in the range 200?400 nm. The effects of the solvent polarity and hydrogen bonding on the absorption spectra were interpreted by means of linear solvation energy relationships using a general equation of the form ? = ?0 s?* + a? + b? and by two-parameter models presented by the equation ? = ?0 s?* + a?, where ?* is a measure of the solvent polarity/polarisability, ? is the scale of the solvent hydrogen bond donor acidities and ? is the scale of the solvent hydrogen bond acceptor basicities. The solvent and substituent effects on the electronic absorption spectra of the investigated hydantoins is discussed.

Resonance and solvent effects on absorption spectra of some 2- and 4-( - M)-substituted aniline derivatives

1983 ◽  
Vol 36 (4) ◽  
pp. 701 ◽  
Author(s):  
T Yokoyama ◽  
RW Taft ◽  
MJ Kamlet
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Spectral Data ◽  
Absorption Spectra ◽  
Solvent Effects ◽  
Hydrogen Bond Donor ◽  
Intermolecular Hydrogen Bonds ◽  
Hydrogen Bond Acceptor ◽  
Aniline Derivatives ◽  
Hydrogen Bonded

The N-H protons of N-methyl-2-X-aniline derivatives remain intramolecularly hydrogen bonded in HBA (hydrogen bond acceptor) solvents where X = COOMe and NO2, but form intermolecular hydrogen bonds to the HBA solvents where X = CN. The order of response of vmax to solvent HBA basicity for the Cl → C2 bands of N-unsubstituted-2-(-M)-substituted aniline derivatives and the Cl → C4 bands of 4-(-M)-substituted aniline derivatives follows the orders of the hydrogen bond donor acidities of the amine protons, which are determined primarily by the mesomeric effects of the 2- and 4-substituents. The spectral data indicate that intramolecularly hydrogen bonded 2-(-M)-substituted aniline derivatives are near sp2 hybridized in non-HBA solvents and, unlike several 4-substitute anilines, do not undergo significant rehybridization in HBA solvents. Bath ochromic shifts resulting from hydrogen bonds by corresponding 2- and 4-substituted aniline derivatives to HBA solvents are of similar magnitudes.

scholarly journals A linear solvation energy relationship study for the reactivity of 2-substituted cyclohex-1-enecarboxylic and 2-substituted benzoic acids with diazodiphenylmethane in aprotic and protic solvents

2007 ◽  
Vol 72 (12) ◽  
pp. 1217-1227 ◽  
Author(s):  
Jasmina Nikolic ◽  
Gordana Uscumlic
Keyword(s):  
Solvent Effects ◽  
Rate Constants ◽  
Chemical Reactivity ◽  
Linear Regression Analysis ◽  
Quantitative Relationship ◽  
Multiple Linear Regression Analysis ◽  
Reaction Rates ◽  
Benzoic Acids ◽  
Linear Solvation Energy ◽  
Substituted Benzoic Acids

The rate constants for the reaction of 2-substituted cyclohex-1-enecarboxylic acids and the corresponding 2-substituted benzoic acids with diazodiphenylmethane were determined in various aprotic solvents at 30 ?C. In order to explain the kinetic results through solvent effects, the second order rate constants of the reaction of the examined acids were correlated using the Kamlet-Taft solvatochromic equation. The correlations of the kinetic data were carried out by means of multiple linear regression analysis and the solvent effects on the reaction rates were analyzed in terms of the contributions of the initial and transition state. The signs of the equation coefficients support the proposed reaction mechanism. The quantitative relationship between the molecular structure and the chemical reactivity is discussed, as well as the effect of geometry on the reactivity of the examined molecules.

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