Synthesis and spectroscopic behaviour of metal complexes of meso-alkylidenyl carbaporphyrinoids and their expanded analogues.

Treatment of meso-malonylidene-(m-benzi)porphyrin and meso-malonylidene-(m-benzi)pentaphyrin with Pd(ii), Au(iii), Ni(ii) and Ag(i) afforded the corresponding metal complexes. The synthesized metal complexes were characterized by spectroscopy including single crystal X-ray, NMR and mass spectrometry. Most metal complexes were stable in solution. The metal complexes showed strong absorption in the near IR region.

Unprecedented non-aromatic, conformationally locked dibenzohexaphyrin analogs carrying multiple meso-exocyclic double bonds.

Acid-catalysed, '3+3' condensation of m-bispyrryl benzene derivatives with acetone afforded new non-aromatic macrocycles that can be converted to meso-alkylidenyl dibenzohexaphyrins carrying four exocyclic double bonds at meso-positions by DDQ oxidation.

Stepwise π-extension of meso-alkylidenyl porphyrins through sequential 1,3-dipolar cycloaddition and redox reactions.

Several regioselectively π-extended, pyrrole fused porphyrinoids have been synthesized by the 1,3-dipolar cycloaddition of meso-alkylidene-(benzi)porphyrins. Pd(II) complexes gave oxidation resistant, bis-pyrrole fused adducts. The repeated 1,3-dipolar cycloaddition followed by oxidation-reduction of pentaphyrin analogs afforded π-extended porphyrin analogs.