David Ostfeld

UNUSUAL METALLOPORPHYRINS VIII: Synthesis of Ruthenium Mesoporphyrin IX Dimethylester Carbonyl and its Imidazole Derivatives; Observation of a new type of Tautaumerism—Metal Shuttling

Abstract Ruthenium (II) porphyrin complexes have been made with mesoporphyrin IX dimethyl ester and tetraphenylporphine in which one axial position is occupied by a carbonyl group. The other axial position is shown to be either occupied by a loosely bound ligand or entirely empty. The imidazole,4,5-dimethylimidazole, and 3,5-dimethylpyrazole complexes of the mesoporphyrin complex, I, are made. Variable temperature pmr studies on the imidazole and 3,5-dimethylimidazole complexes show the metal nitrogen bond to be moving rapidly between the two imidazole nitrogens at high temperatures.

UNUSUAL METALLOPORPHYRINS XI. FURTHER STUDIES ON RHENIUM (I) PORPHYRINS

Abstract Experimental details are given for the preparation of two complexes of rhenium with mesoporphyrin IX dimethyl ester, Re(CO)3(H-MPIXDME) and μ-(MPIXDME)[Re(CO)3]2. The molecular geometry of these complexes is discussed and it is concluded that they do not have simple predictable structures. Three possible structures are discussed for the dirhenium complex. An empirical explanation, similar to the “eighteen electron rule” for metal carbonyls, is given as to why rhenium is in the +1 state. Porphyrin complexes containing a single atom of rhenium and an atom of another metal (Ag+, Hg++, or Pb++) were detected spectrally but not isolated. Finally the monorhenium complex is compared to the proposed intermediate in metal insertion, in which the metal sits above the porphyrin ring.