This report describes versatile and catalyst-free methods for the introduction of group-16 elements at the meso-positions of diarylporphyrins. The methods involve nucleophilic aromatic substitution (S N Ar) of the meso-bromodiarylporphyrin. The reaction proceeds in almost quantitative yield in most cases. Reactions with various phenols afford the corresponding meso-phenoxyporphyrins, except for the reaction with 4-hydroxypyridine, which affords a meso-(N-pyridonyl)porphyrin. With the exception of thiocyanate, reac-tions involving sulfur-centered nucleophiles proceed smoothly and afford the corresponding functionalized porphyrins, including a meso-sulfonylporphyrin that was obtained from benzenesulfinate. To overcome problems associated with the handling of chalcogenols (instability, bad odors), we also used dichalcogenides as nucleophile precursors to afford the corresponding meso-sulfanyl or selanylporphyrins. The instability of a novel meso-tellanylporphyrin is also revealed.[a] Dr.

A series of porphyrin dimers bridged by one or two rigid arylenedioxy linkers was successfully synthesized by catalystfree meso-aryloxylation involving nucleophilic aromatic substitution. The orientational freedom and conformation of the two porphyrin macrocycles in the mono-bridged dimers depended on the steric hindrance between the macrocycles and substituents on the arylenedioxy linkers. On the other hand, the bis-bridged dimers exhibited a highly rigid cofacial conformation with a distinct interplanar distance. The fluorescence quantum yields of the bis-bridged dimers (Φ fl = 0.094 and 0.096) were quite similar to those of the monomers (Φ fl = 0.13). Owing to their high rigidities, the nonradiative deactivation of the photoexcited states associated with dimerization, which are observed for reported dimers, are mostly suppressed, thus suggesting that those dimers have highest rigidities among the cofacial porphyrin dimers exploring emission properties. Cyclic voltammetry revealed the electronic communication between the porphyrin macrocycles in the closely stacked bis-bridged dimer.