Synthesis, Structural and Optical Properties of Tetrabenzoporphyrin Complexes Bearing Four or Eight Peripheral Phenyl Groups

A series of free‐base and phosphorus(V) complexes of tetrabenzoporphyrin (TBP) and some phosphorus(V) porphyrins containing four or eight phenyl groups on the periphery have been synthesized and characterized by X‐ray crystallography, electronic absorption, and magnetic circular dichroism (MCD) spectroscopy, together with quantum chemical calculations. All phosphorus TBP and meso‐tetraphenyl porphyrin complexes adapted ruffled conformations due to the small P(V) ion, although the Zn(II)TBPs containing eight phenyl (Φ) groups at the so‐called β and α positions showed planar and saddled structures in the solid state, due to, respectively, marginal or severe steric hindrance between the neighboring Φ groups. All P(V)TBPs showed the Soret and Q bands beyond 450 and 700 nm, respectively, which are some of the longest wavelengths exhibited by metallated TBPs reported to date. Of the eight Φ group‐substituted P(V)TBPs, those substituted at α positions always showed absorption bands at longer wavelengths than those at β positions, which was reproduced by calculated absorption spectra. The Soret band positions of meso‐tetraphenylated P(V) species without fused benzo‐groups (ca. 430–440 nm) were also some of the longest among metalloporphyrins of this type. The first synthesis of tetrabenzoporphyrin phosphorus(V) complexes has been developed. All phosphorus(V) compounds showed the Soret and Q bands beyond 450 and 700 nm, respectively. The effects of fused benzo‐groups and peripheral substituted phenyl groups were rationalized by theoretical calculations.