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Substituent effects on the EPR a N values of symmetrically para ‐disubstituted diphenyl nitroxides
Author(s) -
Zhang YuHuang,
Jiang Bin,
Zhou ChengMing,
Jiang XiKui
Publication year - 1994
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.19940120606
Subject(s) - chemistry , electron paramagnetic resonance , substituent , hyperfine structure , delocalized electron , spin (aerodynamics) , polar , nitrogen , computational chemistry , crystallography , medicinal chemistry , thermodynamics , nuclear magnetic resonance , organic chemistry , atomic physics , quantum mechanics , physics
Abstract Nitrogen hyperfine splitting constants (a N values) of seven symmetrically para‐ disubstituted diphenyl nitroxides (1‐Y's) were measured by EPR and used in conjunction with five literature values in our correlation analysis. The correlation of these a N values by single‐parameter Eq. 1 and dual‐parameter Eq. 2 shows that the application of Eq. 2 does not significantly improve the correlation. But our data can also be interpreted by the proposition that the spin‐delocalization effect is not completely nonexistent and that it might have revealed itself through the a N values of two very weakly polar substituents with pronounced spin‐stabilizing abilities, i.e ., SMe and SiMe 3 .