Molecular Mechanics (MM3) calculations on sulfides

Abstract

The structures of eleven sulfide compounds including methanethiol, ethanethiol, dimethyl sulfide, ethyl methyl sulfide, di‐tert‐butyl sulfide, thiacyclopentane, thiacyclobutane, 5‐thiabicyclo [2.1.1] hexane and 7‐thiabicyclo [2.2.1] heptane have been calculated to agree with experimental data, along with the vibrational spectra of the first three of these. The heats of formation of 24 sulfides (including mercaptans) have also been calculated to agree with experimental data. In general, the force field for sulfides seems to be similar in accuracy with that for hydrocarbons.

Ab initio and molecular mechanics (MM3) calculations on alkyl- and arylboronic acids

“…The MM3 force field [8][9][10] has significantly advanced the accuracy of these calculations. MM3 can accurately handle many different functional groups, including alcohols and ethers, 11 amines, 12 aldehydes and ketones, 13 carboxylic acids and esters, 14 sulfides 15 and sulfones 16 phosphines. 17 Force field parameters for alkylboronic acids have been developed for a generic force field 18 in which reproducing the geometry was the main goal.…”

Molecular Modeling of Energetic Materials: The Parameterization and Validation of Nitrate Esters in the COMPASS Force Field

“…Popular force fields, such as MM3 [3][4][5][6][7][8][9][10][11][12][13], AMBER [14][15], and CHARMM [16], have been designed mainly to study biologically interesting molecules. The COMPASS force field, on the other hand, has been specifically designed for material science applications.…”

Heats of formation of organic molecules by ab initio methods: Thiaalkanes

“…The value calculated by MM3 [8] for this compound is -40.91 kcavmol, which is 0.77 kcaVmol more negative than the ab initio value. The agreement seems adequate.…”

“…For 2-methyl-lpropanethiol, the calculated value is about 2 kcaVmol greater than the experimental value. When we examine the molecular mechanics heat of formation treatment previously published for this class of compounds [8], we find that in that work the calculated value for H , was 0.93 kcal/mol more positive than the experimental value. The discrepancy is less in the molecular mechanics work than in the ab initio work, partly because the value was included in the molecular mechanics least squares parameter optimization, and hence deformed the fitting somewhat to minimize the error, while the value was not included here in the ab initio work.…”