Octaethylporphyrin

Octaethylporphyrin (H2OEP) is an organic compound that is a relative of naturally occurring heme pigments. The compound is used in the preparation of models for the prosthetic group in heme proteins. It is a dark purple solid that is soluble in organic solvents. When treated with ferric chloride in hot acetic acid solution, it forms the square pyramidal complex Fe(OEP)Cl. It also forms the square planar complexes Ni(OEP) and Cu(OEP).
Unlike naturally occurring porphyrins, the conjugate base of H2OEP has four-fold symmetry, which simplifies spectroscopic analysis. In contrast to tetraphenylporphyrin and related analogues, H2OEP features unprotected meso positions. In this way, it is a more accurate model for naturally occurring porphyrins.
H2OEP is prepared by condensation of 3,4-diethylpyrrole with formaldehyde.