SYNTHESIS AND CHARACTERIZATION OF HOMOPORPHYRIN AND HETEROPORPHYRIN DIMERS INVOLVING A RHODIUM-INDIUM BOND

The synthesis of a novel family of metalloporphyrin dimers containing a metal-metal (transition-non-transition metal) bond is presented. The reduction by NaBH4 of the transition metal porphyrin complexes (Por)R h-III(Cl) generates the low oxidation state complexes (PorRh1- Na+, wh ich by reaction with chloro-indium-porphyrin derivatives. (Por)In-III( Cl), give rise to the above new family. By choosing the appropriate po rphyrin ligand it is possible to vary the bond stability in these dime rs systematically. The synthesis of porphyrin dimers involving rhodium -indium bonds, and their full characterization on the basis of H-1 NMR , UV-visible and FT-IR spectroscopy are described. A preliminary study of the photosensitivity of these complexes provides sufficient inform ation about the: stability of the metal-metal bond.