ISSN:
0020-7608
Keywords:
Computational Chemistry and Molecular Modeling
;
Atomic, Molecular and Optical Physics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
This work examines the possibility of finding an electron-hole and an electron-pair simultaneously in a π-system substituted by an electron-donating (NH2) and/or electron-withdrawing (NO2) group. The contributions of various ionic [(+), ( ↑ ↓ )] structures are calculated from ab initio SCF-CI wave functions, using a recently developed general multielectron population analysis. The molecules studied are two monosubstituted ethylenes, aminoethylene and nitroethylene, and a disubstituted ethylene, the 2-nitroethenamine (push-pull ethylene) in its two configurational forms. The influence of the NH2 and/or NO2 group in delocalization and ionic (vs. covalent) character of the C=C double bond are investigated, along with examining the experimental chemist formalism of electron-pair “displacements” in several resonance structures. Analysis of mutual dependence of an electron-hole and an electron-pair, at short and long distances, leads to the conclusion that a push-pull π-system can stimulate the simultaneous existence of an electronhole and an electron-pair even for nonvicinal positions. The relationship between the electronpair distributions and contributions of the corresponding structures are also examined; the effects of electronic correlation are analyzed as well. © 1992 John Wiley & Sons, Inc.
Additional Material:
7 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/qua.560440304
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