A topochemically active diynol. The effect of temperature on the crystal structure of 6-hydroxyhexadiynyl benzoate, PhC(O)OCH2CC–CCCH2OH

The diynol ester PhC(O)OCH2CC–CCCH2OH readily forms very long (4 cm) needle-shaped crystals. The crystal structure in the range 100–293 K contains strong O–H⋯O hydrogen bonds which link molecules related by the operation of a 21 screw axis into chains which are parallel to the long axis of the needle. Coefficients of linear expansion suggest that attractive intermolecular forces are strongest in the direction of the needle axis.