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:
Geometries have been optimized using molecular-orbital calculations (a) with a 4-31G Gaussian basis set for carbanions CH2X- where X = H, CH3, NH2, OH, F, C≡CH, CH≡CH2, CHO, COCH3, CN, and NO2; and (b) with an STO-3G basis set for methyl acetate and acetyl deprotonated methyl acetate. All the carbanions containing unsaturated substituents are planar, with a considerable shortening of the C—X bond. Carbanions containing saturated substituents are pyramidal with the out-of-plane angle α increasing with the electronegativity of the substituent. Double-zeta basis set calculations give proton affinities over the range 449 (for CH3CH2-) to 355 kcal/mol (for CH2NO2-), with all unsaturated anions having smaller affinities than saturated anions. The correlation of proton affinities with 1s binding energies, and with charges on both the carbon of the anion and on the acidic proton of the neutral molecule are examined.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/qua.560180604
