Kinetics and thermodynamics of reversible disproportionation–comproportionation in redox triad oxoammonium cations – nitroxyl radicals – hydroxylamines

Kinetics and thermodynamics of reversible disproportionation–comproportionation in redox triad oxoammonium cations – nitroxyl radicals – hydroxylamines Full article

Journal

Journal of Physical Organic Chemistry
ISSN: 0894-3230 , E-ISSN: 1099-1395

Output data

Year: 2014, Volume: 28, Number: 1, Pages: 17-24 Pages count : 8 DOI: 10.1002/poc.3392

Authors

Sen’ Vasily D. ¹ , Tikhonov Ivan V. ² , Borodin Leonid I. ² , Pliss Evgeny M. ² , Golubev Valery A. ¹ , Syroeshkin Mikhail A. ³ , Rusakov Alexander I. ²

Affiliations

1	Institute of Problems of Chemical Physics Russian Academy of Sciences Chernogolovka 142432 Russian Federation
2	P.G. Demidov Yaroslavl State University Yaroslavl 150000 Russian Federation
3	N. D. Zelinsky Institute of Organic Chemistry Russian Academy of Sciences Moscow 119991 Russian Federation

Kinetics and equilibrium of the acid-catalyzed disproportionation of cyclic nitroxyl radicals R 2NO• to oxoammonium cationsR 2 NO + and hydroxylamines R 2 NOH is deﬁned by redox and acid–base properties of these compounds. In a recent work(J. Phys. Org. Chem. 2014, 27, 114-120), we showed that the kinetic stability of R2NO• in acidic media depends on the basicityof the nitroxyl group. Here, we examined the kinetics of the reverse comproportionation reaction of R2NO+ and R2NOH to R2NO•and found that increasing in –I-effects of substituents greatly reduces the overall equilibrium constant of the reaction K4. Thisoccurs because of both the increase of acidity constants of hydroxyammonium cations K3H+ and the difference between the re-duction potentials of oxoammonium cations ER2NO+/R2NO• and nitroxyl radicals ER2NO•/R2NOH. pH dependences of reduction poten-tials of nitroxyl radicals to hydroxylamines E1/3Σ and bond dissociation energies D(O–H) for hydroxylamines R2NOH in water weredetermined. For a wide variety of piperidine- and pyrrolidine-1-oxyls values of pK3H+ and ER2NO+/R2NO• correlate with each other,as well as with the equilibrium constants K4 and the inductive substituent constants σI. The correlations obtained allow predictionof the acid–base and redox characteristics of redox triads R2NO•–R2NO+–R2NOH.

Sen’ V.D. , Tikhonov I.V. , Borodin L.I. , Pliss E.M. , Golubev V.A. , Syroeshkin M.A. , Rusakov A.I.
Kinetics and thermodynamics of reversible disproportionation–comproportionation in redox triad oxoammonium cations – nitroxyl radicals – hydroxylamines
Journal of Physical Organic Chemistry. 2014. V.28. N1. P.17-24. DOI: 10.1002/poc.3392 WOS Scopus OpenAlex

Web of science:	WOS:000346789100003
Scopus:	2-s2.0-84920424391
OpenAlex:	W2300732104

DB	Citing
OpenAlex	51
Scopus	48
Web of science	46