Low Temperature Crystal Structure of 5-Hydroxy-1,7-Bis-(4-Hydroxy-3-Methoxy-Phenyl)-Hepta-1,6-Dien-3-one

Abstract

The title compound 5-Hydroxy-1,7-bis-(4-hydroxy-3-methoxy-phenyl)-hepta-1,6-dien-3-one crystallizes in orthorhombic space group Pca2₁ with two molecules in the asymmetric unit. The unit cell parameters are: a = 35.5368(8), b = 7.7799(2), c = 12.6796(3) Å, D _calc = 1.396 Mgm⁻³, V = 3505.6(2) Å³ and Z = 8. The two aromatic rings in both the molecules are found almost coplanar, their dihedral angles are 18.8° and 13.8°, respectively. The molecular packing is stabilized by strong O–H···O and C–H···O types of hydrogen bonding interactions. The keto and enol groups form an strong O–H···O intra-molecular interaction in both molecules of asymmetric unit. The molecular alignment in the crystal forming a staircase type of stacking through cross link intermolecular interactions.

Graphical Abstract

[Graphical abstract: Crystal structure analysis of 5-Hydroxy-1,7-bis-(4-hydroxy-3-methoxy-phenyl)-hepta-1,6-dien-3-one crystallizes in orthorhombic space group Pca2₁, with two molecules in the asymmetric unit and it is a new polymorph of curcumin. The unit cell parameters are : a = 35.5368(8), b = 7.7799(2), c = 12.6796(3) Å, D _calc = 1.396 Mgm⁻³, V = 3505.6(2) Å³ and Z = 8. The molecular packing is stabilized by O–H···O and C–H···O types of hydrogen bonding interactions.]