ISSN:
0009-2940
Keywords:
Conformational analysis
;
Benzene, donor-acceptor-substituted
;
Benzene ring, distortion of
;
Hydrogen bonding, intramolecular
;
Calculations, AM1
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The X-ray crystallographic analysis of the mono-, di-, and tri-potassium salts 2b - d of trinitrophloroglucinol (2a) show their benzene rings to become considerably more distorted on successive deprotonation. A parallel increase in C - C, and a decrease in C - O and C - N bond lengths leading to a radialenetype structure is also observed. For 2b, two chemically different molecules are found in the crystal which differ in their hydrogen-bond pattern as well as in their average bond lengths and deviation of their benzene rings from planarity. AM1 calculations show that for 2b,d a multitude of structures, differing widely in the deviation of their benzene cores form planarity, can exist within a small energy range ( 〈 3 kcal/mol). The experimental and computational results are discussed in terms of a model that emphasizes “push-pull” interactions as the main cause for the distortions of the benzene rings in compounds of type 1 and 2.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19911240810
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