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Theoretical studies on the structure and electronic properties of 3‐isothiazolones
Author(s) -
Morley John O.,
Charlton Michael H.
Publication year - 1995
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/qua.560550407
Subject(s) - chemistry , ab initio , computational chemistry , electronic structure , sulfur , basis set , nucleophile , atomic charge , atom (system on chip) , reactivity (psychology) , gaussian orbital , homo/lumo , bond length , polarization (electrochemistry) , elementary charge , ab initio quantum chemistry methods , molecule , density functional theory , organic chemistry , electron , physics , quantum mechanics , medicine , alternative medicine , pathology , computer science , embedded system , catalysis
The structure of 4,5‐benzo‐3‐isothiazolone and 5‐phenyl‐2‐( E )‐styryl‐3‐isothiazolone have been calculated both at the semiempirical AM 1 level and by using the ab initio 4‐31 G basis set. Neither method gives a satisfactory account of the bond lengths and angle at the sulfur atom in comparison with crystallographic data, but the inclusion of polarization functions on the sulfur atom alone gives a marked improvement in the theoretical results. The conformations, structure, and electronic properties of a series of other antifungal 3‐isothiazolones have been calculated by the same method. Although structural effects do not appear to play an important role in the mechanism of the inhibition of fungi by the 3‐isothiazolones described here, the electronic properties calculated in terms of the atomic charge at sulfur and the LUMO energy appear to relate to their known reactivity with nucleophiles and their observed biological activity. © 1995 John Wiley & Sons, Inc.