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14 N and 35 Cl nuclear quadrupole resonance data for nitrogen mustards: Attempted correlations with chemical and biological activities
Author(s) -
Buess M. L.,
Bray P. J.,
Sheppard D. W.
Publication year - 1984
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270220203
Subject(s) - chemistry , nuclear quadrupole resonance , aniline , nitrogen , resonance (particle physics) , quadrupole , spectral line , lone pair , hydrolysis , alkylation , nuclear magnetic resonance , computational chemistry , organic chemistry , molecule , atomic physics , physics , catalysis , astronomy
The 14 N nuclear quadrupole resonance (NQR) spectra of several nitrogen mustard compounds are reported and analyzed in the framework of the Townes and Dailey theory. For the aniline derivatives, a correlation exists between l –σ (where l is the nitrogen lone pair electron density and σ the average NC sigma‐bond electron density) and the enhanced Hammett sigma constant σ − . An improved correlation is obtained between l –σ and σ R − , which emphasizes the importance of resonance effects in determining l –σ. The increase of hydrolysis and alkylation rates with increasing values of l –σ is in agreement with the identification of the aziridinium ion as the intermediate in aromatic nitrogen mustard hydrolysis and alkylation. A possible correlation is noted between the 35 Cl NQR spectra for some of the mustards and measures of toxic and antitumor activity.