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Ab initio vibrational analysis of three rotamers of 2‐propen‐1‐imine, H 2 CCHHCNH, and methanimine, H 2 CNH
Author(s) -
Panchenko Yurii N.,
Krasnoshchiokov Sergei V.,
Bock Charles W.
Publication year - 1988
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.540090502
Subject(s) - conformational isomerism , isotopomers , ab initio , chemistry , imine , cis–trans isomerism , molecule , ab initio quantum chemistry methods , computational chemistry , crystallography , stereochemistry , organic chemistry , catalysis , biochemistry
The results of complete Hartree‐Fock (HF)/6–31G geometry optimization and HF/6–31G//HF/6–31G force fields evaluations of three rotamers of the H 2 CCH–HCNH molecule ( s ‐ trans – d ‐ trans –, s ‐ trans – d ‐ cis ‐ and s ‐ cis – d ‐ trans ‐2‐propen‐1‐imine) and the H 2 C=N–H molecule are reported. All three conformers were found to be planar with the s ‐ trans – d ‐ trans conformer lowest in energy. This was corroborated by further complete optimizations of the geometries of the s ‐ trans – d ‐ trans and s ‐ trans – d ‐ cis conformers at the HF/6–31G*(5D) level as well as single‐point MP4/6–31G*//HF/6–31G*(5D) calculations. The assignment of the vibrational frequencies of the propenimine rotamers and some isotopomers of methanimine are also reported. The majority of the experimental frequencies of propenimine in the gaseous phase are found to belong to the s ‐ trans – d ‐ trans form, but a few frequencies are attributed to the high‐energy s ‐ trans – d ‐ cis conformer.