A new crystal form of methyl bacteriopheophorbide a

The structure of a new crystal form of methyl bacteriopheophorbide a, C 36 H 40 N 4 O 6 , which does not contain benzene molecules of crystallization, has been determined at 200 K. The molecule is slightly ruffled with maximum displacements from planarity of ±0.21 A in all five rings. The crystal packing is dominated by π-π interactions between pyrrole rings I and III of adjacent molecules, which are separated by 3.58 A