Oxazolochlorins. 14. 8-Oxo-5,10,15,20-tetra­phenyl-7-oxa­porphyrin N²⁴-oxide

The crystal structure of 8-oxo-5,10,15,20-tetra­phenyl-7-oxaporphyrin N²⁴-oxide is compared with its isomer, 8-oxo-5,10,15,20-tetra­phenyl-7-oxaporphyrin N²²-oxide, carrying the N-oxide at the opposing nitro­gen, and the parent tetra­aryl­porphyrin N-oxide. A detailed conformational analysis reveals subtle differences in the nonplanar conformations of their chromophores.