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Molecular mechanics studies (MM4) of sulfides and mercaptans

✍ Scribed by Allinger, Norman L.; Fan, Yi

Publisher
John Wiley and Sons
Year
1997
Tongue
English
Weight
307 KB
Volume
18
Category
Article
ISSN
0192-8651

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✦ Synopsis

The MM4 force field has been extended to the title class of compounds. The vibrational spectra, structures, conformational equilibria, and heats of formation have been studied for 47 conformers of 29 compounds. In general, the properties may be calculated with accuracy that is competitive with that for hydrocarbons. The structures are better fit than previously because of the inclusion of a torsion᎐bend interaction term, which has its origin in the lone Ž . pair Bohlmann effect. Available experimental data do not suffice to yield detailed torsional potentials, or geometries as a function of torsion angle, and these quantities were determined by ab initio calculations at the MP2r6-31G U level. The rms error in the calculated frequencies of seven representative Ž . structures with a total of 64 experimental and 96 ab initio frequencies is 25 cm y1 . The heats of formation for 23 compounds have a weighted rms error of 0.36 kcalrmol.

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