(2E,5E)-2,5-Bis(4-hydroxy-3-methoxybenzylidene)cyclopentanone ethanol monosolvate

Abstract

In the title structure, C21H20O5· C2H5OH, the curcumine-type molecule has a double E conformation for the two benzylidene double bonds [C=C = 1.342 (4) and 1.349 (4) Å] and is nearly planar with respect to the non-H atoms (r.m.s. deviation from planarity = 0.069 Å). The two phenolic OH groups form bifurcated hydrogen bonds with intramolecular branches to adjacent methoxy O atoms and intermolecular branches to either a neighbouring molecule or an ethanol solvent molecule. The ethanol O atom donates a hydrogen bond to the keto O atom. These hydrogen bonds link the constituents into layers parallel to (101) in the crystal structure.