Pyriporphyrins with three different orientations for the pyridine moiety have been prepared using a '3 + 1' strategy. The nonaromatic pyriporphyrins are stable so long as phenyl substituents are present at the meso-positions adjacent to the pyridine ring. An aromatic dihydropyriporphyrin with an external CO2Ph protective group has also been prepared from 2,4-pyridinedicarbaldehyde.

Azuliporphyrins were reacted with [Ir(COD)Cl](2) in refluxing o- or p-xylene to give novel iridium(III) derivatives that regioselectively incorporated an oxidized solvent molecule. The iridium(III) is inserted within the porphyrinoid macrocycle and possesses an additional apical acyl unit.

ABSTRACT:Even though oxypyriporphyrin, a pyridone-containing porphyrinoid system, has the equivalent coordination core to true porphyrins, its coordination chemistry has been little explored. In this study, the first examples of palladium(II), platinum(II) and silver(II) oxypyriporphyrins have been synthesized. Conventional conditions failed to result in the formation of a platinum(II) complex, but moderate yields were obtained when oxypyriporphyrin was reacted with platinum(II) chloride in refluxing mixtures of DMF and acetic acid containing potassium acetate. The palladium(II) and platinum(II) derivatives were characterized by X-ray crystallography. The structurally analogous carbaporphyrinoid system oxybenziporphyrin was also shown to react with platinum(II) chloride under the same conditions to give a platinum(II) hydroxybenziporphyrin complex. Unlike oxybenziporphyrin, this complex is only weakly diatropic. In the presence of base, the diatropic character was reasserted to afford an aromatic anionic species.

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