Abstract The molecular structures of various conformers of 2-hydroxy-1, 4-naphthoquinone; 3-(alk-1-enyl)-2-hydroxy-1, 4-naphthoquinones; 2, 5, 8-trihydroxy-1, 4-naphthoquinone; and 3-(alk-1-enyl)-2, 5, 8-trihydroxy-1, 4-naphthoquinones were studied by density functional theory (B3LYP/6-31 (d), B3LYP/6-31 (d, p)) and ab initio (MP2/6-31G, MP2/6-31 (d)) methods. The strengths of the intramolecular hydrogen bonds formed by the β-hydroxy ...
