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Molecular mechanics calculations (MM3) on nitriles and alkynes
Author(s) -
Goldstein Elisheva,
Ma Buyong,
Lii JennHuei,
Allinger Norman L.
Publication year - 1996
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/(sici)1099-1395(199604)9:4<191::aid-poc765>3.0.co;2-9
Subject(s) - chemistry , dipole , computational chemistry , standard enthalpy of formation , nitrile , force field (fiction) , bond length , quantum chemical , triple bond , organic chemistry , molecule , double bond , quantum mechanics , physics
The MM3 force field has been extended to include the nitriles and alkynes. Structures, heats of formation, dipole moments and conformational equilibria for aliphatic nitriles and alkynes compounds are fitted to within experimental error. The vibrational spectra for aliphatic nitriles and alkynes were studied, and the experimental values were fitted to an rms error of about 30 cm −1 . Previous MM2 studies of nitriles and alkynes left unresolved the length of the C sp (SINGLE BOND)C sp 3bonds in isopropylnitrile, 3‐methylbutyne, and tert ‐butylacetylene. In each of these compounds, previous MM2 results disagree with experiment. The present MM3 studies and quantum mechanical calculations (MP2/6‐31G** and B3LYP/6‐31G*) confirmed the previous MM2 results.