Crystal structure of octaethylxanthoporphinogen dihydrate

Abstract

Crystals of the title compound (I) are tetragonal, space group l4₁/a, with a= 13.801 (1), c= 18.575(6)Å, Z= 4. The chromophore molecule has crystallographic S₄ symmetry with the oxygen atoms of the associated water molecules positioned on this symmetry axis above and below the porphinogen and linked in each case to two opposing pyrrole nitrogen atoms by hydrogen bridge bonds of length 3.016 Å(N–H 0.92, H ⋯ O 2.13 Å). The atoms bonded to a bridging carbon atom form dihedral angles of –8.9 and 41.6° with the planes of the neighbouring pyrrole rings. Each of the four hydrogen atoms of tho two water molecules interacts with a ketone-oxygen atom of a neighbouring molecule such that each molecule of (1) is linked to four other similar molecules (O–H ⋯ O 2.832, O–H 0.89, H ⋯ O 2.01 Å), resulting in the formation, of water-containing tubular cavities. The structure was solved by direct methods and refined to R 0.075 for 1 115 diffractometer measured unique reflections.