Jet cooled rotational spectrum of methyl lactate

We report here the measurements of the rotational spectra of the main, O-d and four C-13 species of methyl-lactate. They have been obtained by free jet millimeter-wave absorption and molecular beam Fourier-transform microwave spectroscopy. Only lines of the most stable conformer, the one with the hydroxyl group acting as a proton donor to the carbonylic group oxygen, have been observed. The 1 3 barrier to internal rotation of the CH3-O methyl group has been determined to be 4.84(2) U mol(-1). The experimental conformational and structural information are compared to those given by MP2/6-311++G(d,p) calculations. (c) 2006 Elsevier B.V. All rights reserved.