A synchrotron study of [5,10,15,20-tetrakis(3- cyanophenyl)porphyrinato-κ4N5,N10,N15,N20]- copper(II) nitrobenzene trisolvate at 80 K1

Porphyrin assemblies display inter­esting photophysical properties and a relatively high thermal stability. Moreover, meso-functionalized porphyrins with virtually fourfold symmetry can be relatively readily synthesized from pyrrole and the appropriate aldehyde. A number of metallo derivatives of 5,10,15,20-tetra­kis­(4-cyano­phen­yl)porphyrin, where the N atom of the linear cyano group can act both as a donor for coordination bonds or as an acceptor for hydrogen bonds, have been structurally characterized by single-crystal X-ray analysis. The supra­molecular and structural chemistry of the corresponding 2- and 3-cyano­phenyl isomers of the parent porphyrin, however, has remained largely unexplored. The crystal structure of [5,10,15,20-tetra­kis­(3-cyano­phen­yl)porphyrinato]copper(II) (CuTCNPP) nitro­benzene tris­olvate, [Cu(C48H24N8)]·3C6H5NO2, has been determined at 80 K by synchrotron single-crystal X-ray diffraction. CuTCNPP exhibits a C2h-symmetric ααββ conformation, despite an unsymmetrical crystal environment, and is situated on a crystallographic centre of symmetry. The CuII ion adopts a genuine square-planar coordination by the four pyrrole N atoms. The 24-membered porphyrin ring system shows no marked deviation from planarity. In the crystal, the CuTCNPP mol­ecules and two nitro­benzene mol­ecules are face-to-face stacked in an alternating fashion, resulting in corrugated layers. The remaining nitro­benzene guest mol­ecule per CuTCNPP resides in the region between four neighbouring columnar stacks of CuTCNPP and sandwiched nitro­benzene mol­ecules, and is disordered over four positions about a centre of symmetry.