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Experimental and theoretical study of the electronic absorption spectra of some 1,2‐benzoquinone diazides: Closed–open tautomerism
Author(s) -
AbuEittah Rafie H.,
Ibrahim Yahya M.
Publication year - 2000
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(2000)78:1<52::aid-qua7>3.0.co;2-b
Subject(s) - chemistry , tautomer , ab initio , computational chemistry , molecule , absorption spectroscopy , spectral line , molecular orbital , derivative (finance) , benzoquinone , electronic structure , stereochemistry , organic chemistry , physics , quantum mechanics , astronomy , financial economics , economics
The electronic absorption spectra as well as molecular orbital (MO) calculations at the ab initio level of some 1,2‐benzoquinone diazides have been studied. The results of spectral study support the open isomer over the closed one (1,2,3‐oxadiazole derivative) and indicate the contribution of both the benzenoid and quinonoid structures to the molecule. Spectral results were confirmed by MO calculations. The results of the latter gave a lower total energy for a benzoquinone diazide than for 1,2,3‐benzoxadiazole structure. Bond length and charge density indicate the contribution of both quinonoid and benzenoid structures for the studied compounds. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 78: 52–62, 2000