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Gas‐Phase Structure of N , N ‐Dimethylglycine
Author(s) -
Lesarri Alberto,
Cocinero Emilio J.,
López Juan C.,
Alonso José L.
Publication year - 2005
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200500103
Subject(s) - conformational isomerism , chemistry , isotopomers , hydrogen bond , ab initio , rotational spectroscopy , intramolecular force , ab initio quantum chemistry methods , crystallography , lone pair , computational chemistry , stereochemistry , molecule , organic chemistry
Three conformers of the neutral amino acid N,N ‐dimethylglycine [(CH 3 ) 2 NCH 2 COOH] were detected in a supersonic expansion by a combination of laser ablation (LA) and molecular‐beam Fourier transform microwave (MB‐FTMW) spectroscopy. A bifurcated methyl‐to‐carbonyl (CH⋅⋅⋅OC) weak intramolecular hydrogen bond might stabilise the most stable conformer of C s symmetry. The second most stable conformer of C 1 symmetry has a hydrogen bond between the hydroxyl group and the lone pair at the nitrogen atom (N⋅⋅⋅HO). The r s and r 0 structures were derived for this conformer from the rotational data for the parent and six minor 13 C, 15 N and OD isotopomers. A third conformer exhibits a cis ‐carboxyl functional group and C 1 symmetry. Ab initio MP2/6‐311++G(d,p) predictions of the spectroscopic parameters were useful in analysing the spectra. In particular, the agreement of the nuclear quadrupole coupling constants with those calculated was conclusive in identifying the different conformers.