Simple, Axial Ligand-Mediated Route to Water-Soluble Iridium Corroles.

The synthesis and purification of water-soluble porphyrin-type compounds for photodynamic therapy and other medical applications is often a tedious exercise. Here, we have investigated the simple stratagem of adding a water-soluble axial ligand to the standard protocol for iridium insertion into simple -triarylcorroles. Early results showed that six-coordinate Ir[TXPC](dna) derivatives, in which TXPC = tris(-X-phenyl)corrole (X = CF, CN, H, and OMe) and dna = dinicotinic acid, are highly water-soluble.

Iridium Corroles Exhibit Weak Near-Infrared Phosphorescence but Efficiently Sensitize Singlet Oxygen Formation.

Six-coordinate iridium(III) triarylcorrole derivatives, Ir[TpXPC)]L, where TpXPC = tris(para-X-phenyl)corrole (X = CF, H, Me, and OCH) and L = pyridine (py), trimethylamine (tma), isoquinoline (isoq), 4-dimethylaminopyridine (dmap), and 4-picolinic acid (4pa), have been examined, with a view to identifying axial ligands most conducive to near-infrared phosphorescence. Disappointingly, the phosphorescence quantum yield invariably turned out to be very low, about 0.02 - 0.

Protonation-Induced Hyperporphyrin Spectra of -Aminophenylcorroles.

UV-vis spectrophotometric titrations have been carried out on -tris(//-aminophenyl)corrole (H[//-TAPC]) and -triphenylcorrole (H[TPC]) in dimethyl sulfoxide with methanesulfonic acid (MSA). Monoprotonation was found to result in hyperporphyrin spectra characterized by new, red-shifted, and intense Q bands. The effect was particularly dramatic for H[-TAPC] for which the Q band red-shifted from ∼637 nm for the neutral species to 764 nm in the near-IR for H[-TAPC].

Synthesis and Molecular Structure of a Copper Octaiodocorrole.

Although rather delicate on account of their propensity to undergo deiodination, β-octaiodoporphyrinoids are of considerable interest as potential precursors to novel β-octasubstituted macrocycles. Presented herein are early results of our efforts to synthesize β-octaiodocorrole derivatives. Oxidative condensation of 3,4-diiodopyrrole and aromatic aldehydes failed to yield free-base octaiodocorroles.

Octaiodoporphyrin.

Interaction of 3,4-diiodopyrrole with 4-trifluoromethylbenzaldeyde under carefully optimized, Lindsey-type conditions at -10 °C has led to the synthesis of the first β-octaiodoporphyrin, H2[I8TpCF3PP]. The free ligand readily yielded Ni, Cu, and Zn complexes, which all proved amenable to single-crystal X-ray structure analyses. The zinc complex Zn[I8TpCF3PP] exhibits the most saddled porphyrin core for any simple porphyrin known to date and a dramatically red-shifted optical spectrum with a Soret maximum at 495 nm.