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Theoretical study of salicylaldehyde conformal isomers and their intramolecular oxygen and hydrogen relations
Author(s) -
Chen Cheng,
Shyu ShuangFuh,
Hsu FuSheng
Publication year - 1999
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1999)74:4<395::aid-qua3>3.0.co;2-q
Subject(s) - intramolecular force , chemistry , salicylaldehyde , hydrogen bond , hydrogen , computational chemistry , density functional theory , oxygen , chemical physics , crystallography , stereochemistry , molecule , organic chemistry , schiff base
To verify the semiempirical‐type localized hydrogen bonding analysis methods introduced by us several years ago, the intramolecular oxygen and hydrogen relations within salicylaldehyde are selected as the major topic in this theoretical study. The B3LYP/6‐31G** density functional method is chosen for both the full‐optimization and frequency‐type calculations. Four ortho‐type planar conformal isomers are proven to be local minima, and four internal rotation transition states are found by QST3‐type calculation. The special interpretations of CHO and OH characteristic frequencies, energy barriers, and thermal chemical results are discussed. In the semiempirical scheme, both local hydrogen bonding population analysis and localized hydrogen bond energy breaking procedures are applied to five pairs of related oxygen and hydrogen atoms in each isomer. The explanations for the strong or weak hydrogen bonds and intra‐CHO repulsion relationships are discussed. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 74: 395–404, 1999