The molecular structure and conformational composition of 3-hexyn-1,6-diol have been studied by the gas electron diffraction method and by ab initio calculations. Four conformers (AA, G+G-, G+G+ and GA) have been taken into account. The experimental data are in accordance with a conformational mixture consisting of 62.2% GG (equal parts of G+G- and G+G+) and 37.8% GA with a standard deviation of 10.3%. Similar results were, however, obtained when a small contribution (0 ≤ x ≥ 12%) from the high energy AA conformer was introduced and the other forms were properly corrected (GG (62.2+x%); GA (37.8 - 2x%)). From the experimental data the total amount of gauche contribution in the two parts of the molecule is accordingly estimated to be in the region 76.0-86.3%. The GG and GA conformers are characterized by the formation of two, respectively one, OH···π hydrogen bonds. (C) 2000 Elsevier Science B.V.
Trætteberg, M., Bakken, P., Hopf, H., Mlynek, C., & Mahle, A. H. (2000). Intramolecular OH/π interaction: The molecular structure and conformations of 3-hexyn-1,6-diol. Journal of Molecular Structure, 554(2–3), 191–202. https://doi.org/10.1016/S0022-2860(00)00663-3