Conformational study of taurine in the gas phase.

The conformational preferences of the amino sulfonic acid taurine (NH(2)-CH(2)-CH(2)-SO(3)H) have been investigated in the gas phase by laser ablation molecular beam Fourier transform microwave spectroscopy (LA-MB-FTMW) in the 6-14 GHz frequency range. One conformer has been observed, and its rotational, centrifugal distortion, and hyperfine quadrupole coupling constants have been determined from the analysis of its rotational spectrum. Comparison of the experimental constants with those calculated theoretically identifies the detected conformer unambiguously. The observed conformer of taurine is stabilized by an intramolecular hydrogen bond O-H...N between the hydrogen of the sulfonic acid group and the nitrogen atom of the amino group.