Intramolecular hydrogen bonding: the molecular structure and conformations of 3-butyn-1-ol

Abstract

The molecular structure and conformational composition of 3-butyn-1-ol have been studied by the gas electron diffraction method and by ab initio calculations. The preferred conformation is gauche, and the experimental data are in accordance with a conformational mixture of 85 ± 10% gauche and 15 ± 10% anti. The most important geometric parameters were determined to be r a(CC): 1.217(1) Å, r a(C 2C 3): 1.469(1) Å, r a(C 1C 2): 1.536(2) Å, r a(CO): 1.414(1) Å, ∠CCC G: 111.6(6)°, ∠CCO G: 113.9(6)°, θ(CC) G: 60.2(1.6)°. The values in parentheses are standard deviations. The experimental data are in accordance with a non-linear HCCC fragment in the gauche conformer.