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.

We present the synthesis and characterization of a new family of expanded meso-alkylidenyl (2,6-pyri)porphyrinoids bearing multiple exocyclic double bonds at the meso-positions. The synthesis was accomplished by using mixed pyrrole condensation. Similar to meso-alkylidenyl porphyrinoids, this study revealed that pyriporphyrinoids do not possess a porphyrin-like, global-aromatic character. The synthesized 2,6-pyripentaphyrin 1 displays selective ratiometric sensing of pyrophosphate anion in organic solvent.

Porphyrins and their structural analogs have drawn continuous attention owing to their physico-chemical properties associated with biological, medical and material chemistry. Consequently, many structural modifications of the porphyrin skeleton have been reported as a fundamental tool for tuning the physico-chemical properties and a variety of new classes of porphyrinoids have emerged. A vast number of applications such as photodynamic therapy (PDT), redox catalysis, chemosensors, nonlinear optical material (NLO) and two photon absorption (TPA) have been studied utilizing these systems. The “so called” meso-alkylidenyl porphyrins have been reported recently as alternative modification methods of the porphyrin skeleton. These compounds possess one or more exocyclic double bonds at meso-positions and are usually non-aromatic systems. The reported spectroscopic as well as structural properties well-corroborate the non-aromatic nature of the macrocycles. However, the protonation behavior and tautomerism are quite different from those of normal porphyrins. Considering the unique properties of meso-alkylidenyl carbaporphyrinoid macrocycles, we present a review on the recent advances in this area of chemistry.

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Oligopyrrolic macrocycles based on the naphthobipyrrole scaffold have been synthesized and characterized. The compounds showed high affinities toward multi‐oxo anions such as dihydrogen phosphate and sulfate anions in acetonitrile. Theoretical calculations for the formation of host–anion complexation revealed that the receptors adopt bowl‐shaped, cone conformations with association constants of ca. 106 m–1 with dihydrogen phosphate anions.