Crystal structure of 5-tert-but-yl-10,15,20-tri-phenyl-porphyrin.

In the title free base porphyrin, C42H34N4, the neighbouring N⋯N distances in the center of the ring vary from 2.818 (8) to 2.998 (8) Šand the phenyl rings are tilted from the 24-atom mean plane at angles varying between 62.42 (2)-71.63 (2)°. The NH groups are involved in intra-molecular bifurcated N-H⋯(N,N) hydrogen bonds. The Ca-Cm-Ca angles vary slightly for the phenyl rings, between 124.19 (18)-126.17 (18)°. The largest deviation from the mean plane of the 24-atom macrocycle is associated with the meso carbon at the substituted tert-butyl position, which is displaced from the mean plane by 0.44 (2) Å. The free base porphyrin is characterized by a significant degree of ruffled (B 1u ) distortion with contributions from domed (A 2u ) and wave [Eg (y) and Eg (x)] modes. In the crystal, mol-ecules are linked by a number of weak C-H⋯π inter-actions, forming a three-dimensional framework. The structure was refined as a two-component inversion twin.