Determination of Hammett ρ Values for Substituted Phenylmercapto-, Phenylsulfinyl-, and Phenylsulfonylacetic Acids

Pasto, Daniel J.; Mcmillan, Donna A.; Murphy, Terrance B.

doi:10.1021/jo01019a043

Cited by 36 publications

(10 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If ρ > 1, then ΔΕ s‐t is more sensitive to the effect of the substituent than benzoic acid dissociation. If 0 < ρ < 1, EWGs still increase ΔΕ s‐t but less than in benzoic acid dissociation . The plot of ΔΕ s‐t for the scrutinized disilavinylidenes against their corresponding σ shows good correlation especially for para series ( R 2 = .98 and .63, with ρ = −2.07 and −1.42, for para and meta series, respectively, Figure ).…”

Section: Resultsmentioning

confidence: 89%

Toward triplet disilavinylidenes: A Hammett electronic survey for substituent effects on singlet‐triplet energy gaps of silylenes by DFT

Ayoubi‐Chianeh

Kassaee

2019

J of Physical Organic Chem

View full text Add to dashboard Cite

To reach for novel triplet silylenes, para‐ and meta‐R‐1,1‐diphenyldisilavinylidenes with various electron donating and withdrawing groups (EDGs and EWGs, respectively) are compared and contrasted using the B3LYP/6‐311++g** method, where para silylenes consist of 1H, 2boldCHbold3, 3OH, 4boldNHbold2, 5F, 6Cl, 7boldCFbold3, 8CHO, 9boldNMebold2, and 10boldNObold2, whereas their meta isomers are bold2′boldCHbold3, 3′OH, bold4′boldNHbold2, 5′F, 6′Cl, bold7′boldCFbold3, 8′CHO, bold9′boldNMebold2, and bold10′boldNObold2. The overall trend for triplet tendency of the latter group based on their singlet‐triplet energy gap (ΔEs‐t) is 3′OH > bold4′boldNHbold2 > 1H > bold2′boldCHbold3 > bold9′boldNMebold2 > 8′CHO > 5′F > 6′Cl > bold7′boldCFbold3 > bold10′boldNObold2 while that for the former, para series is 9boldNMebold2 > 4boldNHbold2 > 3OH > 2boldCHbold3 > 5F > 6Cl > 1H > 7boldCFbold3 > 8CHO > 10boldNObold2. Plotting disilavinylidenes ΔEs‐t, against their corresponding Hammett substituent constants (σp or σm) shows rather significant ρ factors of −2.07 and −1.42 with good correlations of R2 = 0.98 and 0.63, respectively. The negative sign of the ρ indicates that the more EDGs have higher impacts on stabilizing or reaching for the triplet ground states, displaying 4boldNHbold2 and 9boldNMebold2 as two silylenes with triplet ground states. The EWGs increase electrophilicity (ω) making 10boldNObold2 (7.62 eV) the most electrophilic. In contrast, EDGs increase nucleophilicity (N) showing 9boldNMebold2(5.03 eV) as the most nucleophilic silylene. Moreover, 9boldNMebold20.25emshows the highest proton affinity (PA = 388.13 kcal/mol), chemical potential (μ = −3.67 eV), energy of HOMO (EHOMO = −4.46 eV), dipole moment (5.44 debye), and the lowest band gap (ΔEH‐L = −1.59 eV), and electrophilicity (ω = 4.24 eV), with the lowest NBO charge on divalent Si atom (+0.129) among the scrutinized species.

show abstract

Section: Resultsmentioning

confidence: 89%

Toward triplet disilavinylidenes: A Hammett electronic survey for substituent effects on singlet‐triplet energy gaps of silylenes by DFT

Ayoubi‐Chianeh

Kassaee

2019

J of Physical Organic Chem

View full text Add to dashboard Cite

show abstract

“…The alkyl substituted nitrogen atom of monoakylhydrazines constitutes an example of an in either direction completely resonance free unit. The effect of the conjugation possibilities of interposed units on their transmittance efficiency has been thoroughly treated by Marcus,Reynolds,and Miller [25], who also treated the transmitting properties of sulphur, which have been suggested to be more efficient than those of oxygen [23]. There is a difference between non-conjugative and conjugative situations for interposed groups, and even in the latter case between acceptor and donor conjugation.…”

Section: Discussionmentioning

confidence: 99%

Application of the Taft Equation to the Ionisation Constants of Negatively Substituted Monoalkylhydrazines

Pollet

Eynde

1968

Bulletin des Soc Chimique

View full text Add to dashboard Cite

The ionisation constants of perfluorinated and other negatively substituted monoalkylhydrazines have been determined in water, and plotted against the Taft polar substituent constants. A reaction constant of ‐ 2.36 is obtained, providing evidence that, contrary to not negatively substituted monoalkylhydrazines, protonation takes place at the terminal amino group. Perfluoroalkylsubstitution lowers the basicity of hydrazine in such a way that the basicity order of phenyl‐hydrazine is reached. The obtained results allow a discussion about the effectiveness of transmission of electronic effects through an interposed ‐NH‐ unit.

show abstract

“…S-phenyl mercapto acetic acid were prepared and purified by literature method 8 . Piperidinium chlorochromate was prepared by a known procedure 1 and its purity was checked by determining Cr(VI) concentration iodometrically.…”

Section: Methodsmentioning

confidence: 99%

Oxidation of S-Phenylmercaptoacetic Acid by

2013

Chem Sci Trans

View full text Add to dashboard Cite

Oxidation of S-phenylmercaptoacetic acid by piperidiniumchlorochromate (PipCC) in the presence of perchloric acid has been studied in 50% (v/v) aqueous acetic acid medium. The reaction shows unit order dependence each with respect to oxidant and substrate. The order with respect to hydrogen ion concentration is fractional. The rate of oxidation increases with increase in the percentage of acetic acid and increase the ionic strength has negligible effect on the reaction rate. Number of electron transferred during the oxidation process has also determined. From the kinetic observations, the reaction mechanism and rate law has been proposed.

show abstract

Determination of Hammett ρ Values for Substituted Phenylmercapto-, Phenylsulfinyl-, and Phenylsulfonylacetic Acids

Cited by 36 publications

References 0 publications

Toward triplet disilavinylidenes: A Hammett electronic survey for substituent effects on singlet‐triplet energy gaps of silylenes by DFT

Toward triplet disilavinylidenes: A Hammett electronic survey for substituent effects on singlet‐triplet energy gaps of silylenes by DFT

Application of the Taft Equation to the Ionisation Constants of Negatively Substituted Monoalkylhydrazines

Oxidation of S-Phenylmercaptoacetic Acid by

Contact Info

Product

Resources

About