Invariom-model refinement of L-valinol.

The structure of L-valinol [(S)-(+)-2-amino-3-methylbutan-1-ol or hydroxylated L-valine], C5H13NO, has been determined at 100 K by single-crystal X-ray diffraction. The independent atom model geometry, Flack parameter and figures of merit are compared with results from an invariom structure refinement. The latter provides H-atom positions free of independent atom model bias and therefore yields a more accurate hydrogen-bond pattern, and the geometry from invariom refinement shows an improved agreement with results from a quantum chemical geometry optimization.