meso-Octaethylporphyrinogen displaying site selectivity in the stepwise synthesis of polymetallic aggregates with interesting redox properties: the π-binding ability of metalla-porphyrinigens

The present report deals with the synthetic approach to homo- and heteronuclear polymetallic aggregates using the Ni-II-meso-octaethylporphyrinogen complex [{eta(3)-(Et8N4Ni)}{Li(thf)(2)}(2)] (1) as a pi ligand in the reaction with metal halides. The metallation reaction occurs via the probable intermediate of an isomeric form of 1, namely 2, which should be considered an organolithium derivative. Among the polymetallic aggregates, complexes [{eta(5)-(Et8N4Ni)}(2)Co]. 2[Li(thf)(4)] (6) and [{eta(2)-eta(4)-(Et8N4Ni)}(2)Ni-2(mu-Cl)][Li(thf)] (8) display a thermal and photochemical lability. Electron transfer reactions can be photochemically or thermally induced resulting in the formation of metal(0) and oxidized forms of the meso-ctaethylporphyrinogen skeleton.