Offset pi-pi interaction in crystal structure of (-)-gallocatechin-3-O-gallate.

The single crystal of (-)-gallocatechin-3-O-gallate (GCg) was prepared using a solution containing an equimolecular amount of GCg and (-)-epigallocatechin-3-O-gallate (EGCg) in water. The crystal structure of GCg determined by X-ray crystallographic analysis was monoclinic with the space group P2(1) at 223 K. Offset pi-pi interactions formed between the A and A rings, B and B rings, and gallate and gallate rings of GCg, and five intermolecular hydrogen bonds formed between GCgs, GCg and water. The B ring of GCg bonded to C2 was in the axial position and the gallate ring of GCg bonded to C3 was in the pseudoaxial position with respect to the C ring of GCg.