Definitive evidence for the existence of the "sitting-atop" porphyrin complexes in nonaqueous solutions.

Definitive evidence for the intermediate in metalloporphyrin formation produced in the interaction of meso-tetraphenylporphine and [Rh(CO)2Cl]2, the "sitting-atop" complex (SAT), is given in this article. The second-order kinetics of SAT complex formation, the small rate constant for the formation reaction, and the equilibrium study indicate a one-to-one complex between the meso-tetraphenylporphine and [Rh(CO)2Cl]2. The analytical data, infrared spectrum, and especially the proton magnetic resonance lead to a formulati-n of the "sitting-atop" complex shown in Fig. 8.