ISSN:
0538-8066
Keywords:
Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
An earlier correlation between isolated CH stretching frequencies, visCH, and experimental CH bond dissociation energies, in hydrocarbons, fluorocarbons, and CHO compounds, is updated. A stabilization energy, EvS, which reflects only the properties of the radical, is defined by the deviation of a point from the above correlation. EvS values for a variety of radicals are listed and discussed. In H—C—N and H—C—O compounds EvS is low or negligible, due to the low visCH found in these compounds. The conventional definition of ES then represents a serious misnomer, which distracts attention from the probable source of discrepancies between experimental and ab initio values of DH°(C—H), namely, the parent molecules. Stereo electronic effects concerned with the breaking of CH bonds are predicted in a variety of situations.Some experimental determinations of DH°(C—H), viz., in C2H4, HCOOH, CH3CHO, CH3NH2, are considered to be probably in error.Schemes for partitioning energies of atomization into ‘standard’ or ‘intrinsic’ bond energies are criticized.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/kin.550210608
