IR low-temperature matrix and ab initio study on beta-alanine conformers.
For the first time the argon-matrix low-temperature FTIR spectra of beta-alanine are recorded. They reveal a quite complicated spectral pattern which suggests the presence of several beta-alanine conformers in the matrix. To interpret the spectra, the eighteen beta-alanine conformers, stable in the gas phase, are estimated at the B3LYP and MP2 levels combined with the aug-cc-pVDZ. Ten low-energy structures are reoptimized at the QCISD/aug-cc-pVDZ and B3LYP and MP2 levels by using the aug-cc-pVTZ basis sets. Assignment of the experimental spectra is undertaken on the basis of the calculated B3LYP/aug-cc-pVDZ anharmonic IR frequencies as well as careful estimation of the conformer population. The presence of at least three beta-alanine conformers is demonstrated. The detailed analysis of IR spectra points to the possible presence of five additional beta-alanine conformers.
Dobrowolski
Jan Cz
JC
National Medicines Institute, 30/34 Chełmska Street, 00-725 Warsaw, Poland. janek@il.waw.pl
Jamróz
Michał H
MH
Kołos
Robert
R
Rode
Joanna E
JE
Sadlej
Joanna
J
D019295:Computational Biology; D008958:Models, Molecular; D008968:Molecular Conformation; D013055:Spectrophotometry, Infrared; D013696:Temperature; D015091:beta-Alanine / Q000737:chemistry*
D015091:beta-Alanine