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Do Partial Charges Alone Govern the Relative Stability of the Isomeric Heptaheteronortricyclane Anions [P 7− x AS x ] 3⊖ ?
Author(s) -
Burkhardt Armin,
Hönle Wolfgang,
Wedig Ulrich
Publication year - 1991
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.199108281
Subject(s) - valence (chemistry) , electronegativity , chemistry , ab initio , ab initio quantum chemistry methods , arsenic , computational chemistry , chemical physics , crystallography , molecule , organic chemistry
The answer to the question in the title is “no” in the opinion of the authors. The decrease in the skeletal strain, rather than the slight differences in electronegativity between phosphorus and arsenic, seems to direct the As occupation of positions in the P 7 3⊖framework. Ab initio calculations on [P 7− x As x ] 3⊖ systems with x = 0, 1, 2, 3, 7 show that the energy differences between the isomers contributes only ca. 10% of the activation energy for the valence tautomerism. Valence fluctuation therefore cannot favor any particular isomer.