Date Published: May 01, 2010
Publisher: International Union of Crystallography
Author(s): Avijit Ghosh, Ray J. Butcher, Shaikh M. Mobin, M. Ravikanth.
Molecules of the title macrocycle, C36H22N4O4, are located on an inversion center. The porphyrin ring shows a wave-like conformation with adjacent pyrrole rings tilted above the porphyrin plane and the interporphyrin distance is 3.584 (3) Å. The dihedral angles between the meso-furyl groups and the porphyrin plane are 38.87 (7) and 48.29 (7)°; these are much smaller than those observed for meso-tetraphenylporphyrin, indicating that the meso-furyl groups are more inclined towards the porphyrin plane. The decrease in the dihedral angle is due to the presence of intramolecular hydroden bonding between the meso-fury O atom and the β-pyrrole CH group. Intramolecular N—H⋯N hydrogen bonds are also present.
The electronic properties of porphyrin macrocycles can be altered by selectively introducing substituents at meso- or β-positions, see: Lindsey (2000 ▶). For the effect on the electronic properties of introducing five-membered heterocycles such as thiophene and furan at the meso-position in place of six-membered aryl groups, see: Bhavana & Bhyrappa (2001 ▶); Purushothaman et al., (2001 ▶); Gupta & Ravikanth (2002 ▶, 2003a ▶,b ▶, 2005 ▶). For the structure of 5,10,15,20-tetrakis(phenyl)porphyrin, see: Senge (2000 ▶).