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Nuclear quadrupole resonance and molecular orbital studies of charge distribution in H‐bonded complexes of 2‐chloro‐4‐nitrobenzoic acid
Author(s) -
Habeeb M. M.,
Awad M. K.
Publication year - 1995
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260330612
Subject(s) - chemistry , nuclear quadrupole resonance , delocalized electron , proton , molecular orbital , resonance (particle physics) , charge density , quadrupole , natural bond orbital , computational chemistry , hydrogen bond , density functional theory , crystallography , molecule , atomic physics , nuclear magnetic resonance , organic chemistry , physics , quantum mechanics
The charge distribution in hydrogen bridges of varying strengths in solid 2‐chloro‐4‐nitrobenzoic acid complexes was studied using the 35 Cl nuclear quadrupole resonance technique (NQR). The dependence of 35 Cl NQR frequencies on the proton affinities was analysed. Molecular orbital calculations using atom superposition and electron delocalization molecular orbital theory showed that the trends of changes in the charge density on the chlorine, nitrogen and oxygen atoms, and on the binding energy and the bond order of NH and OH groups are consistent with the NQR results. Also, the agreement between theoretical and experimental results showed that the 3,5‐dimethylpyridine complex represents the critical point at 50% proton transfer.