Hydrogen bonds, tautomers, and conformation in 2-hydroxyphenyl 2-hydroxy-2-(beta-naphthyl)vinyl ketone

Single crystal X-ray diffraction and IR spectroscopy have been used to stud y the conformation of 2-hydroxyphenyl 2-hydroxy-2-(alpha -naphthyl)vinyl ke tone in solid state. It was found that one of the two possible enol tautome ric forms is stabilized in the crystal. The 1-hydroxy-3-oxo-1,3-propenylene moiety. O=C-CH=C-OH, shows a strong intramolecular H bond with a definite character of reasonance-assisted hydrogen bond in spite of being in competi tion with ring intermolecular hydrogen bonds. The comparison of the present results with solution NMR data indicates that the molecular geometry in so lid state and in solution are similar.