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Kinetic isotope effect in the protonation of anthracenide salts by MeOH and MeOD role of counterions and solvents
Author(s) -
Rainis A.,
Szwarc M.
Publication year - 1975
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550070611
Subject(s) - chemistry , protonation , kinetic isotope effect , tetrahydrofuran , counterion , dimethoxyethane , anthracene , kinetics , solvent , ion , reaction rate constant , inorganic chemistry , medicinal chemistry , photochemistry , deuterium , organic chemistry , electrolyte , physics , electrode , quantum mechanics
Kinetics of protonation of Li + , Na + , K + , and Cs + salts of anthracene radical anions (A − · ,Cat + ) and dianions (A 2− , 2Cat + ) by MeOH and MeOD in tetrahydrofuran (THF) and dimethoxyethane (DME) led to the determination of the isotope effect ( k H / k D ) in the following reactions:\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm MeOH(MeOD) + A}\bar \cdot {\rm,Cat}^{\rm + } \to MeO^ - {\rm,Cat}^{\rm + } {\rm + AH} \cdot {\rm (D)} $$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm (MeOH)}_{\rm 2} {\rm or (MeOD)}_{\rm 2} {\rm + A}\bar \cdot {\rm,Cat}^{\rm + } \to {\rm MeOH,MeO}^ - {\rm,Cat}^{\rm + } {\rm + AH} \cdot {\rm (D)} $$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm MeOH (MeOD) + A}^{{\rm 2 - }} {\rm,2Cat}^{\rm + } \to {\rm MeO}^ - {\rm,Cat}^{\rm + } {\rm + AH(D)}^{{\rm - 1}},{\rm Cat}^{\rm +} $$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm MeOH (MeOD) + (A,Cat}^{\rm + } {\rm,A}^{{\rm 2 - }} {\rm,Cat}^{\rm + }) \to {\rm MeO}^ - {\rm,Cat}^{\rm + } {\rm + A + AH(D)}^{\rm - },{\rm Cat}^{\rm +} $$\end{document}Studies of cation and solvent influence on the rate constants of these reactions and on the magnitude of the isotope effect permitted us to draw some conclusions about the structure of the pertinent transition states. It seems that only the tight A − ·,Na + pairs participate in the protonation, and on this basis the fraction of tight ion paris of A − ·,Na + in DME was estimated. Our results have been compared with data reported in the literature.