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The synthesis, spectral and structural characterization of meso-aryl sapphyrins and rubyrins containing heteroatoms such as S, O, Se in addition to pyrrole nitrogens are reported. The synthesis of the desired expanded porphyrins has been achieved using a single precursor, the modified tripyrranes containing heteroatoms, through an unprecedented oxidative coupling reaction in moderately good yields. The product distribution and the isolated yields were found to be dependent on the nature of the acid catalyst and its concentration. Use of 0.1 equiv of acid exclusively gave 26π rubyrins while a higher concentration of acid gave a mixture of 18π porphyrin, 22π sapphyrin, and 26π rubyrin. Two additional products, 22π oxasmaragdyrin and 18π oxacorrole, were isolated in the reaction of oxatripyrrane. All of the sapphyrins and rubyrins exhibit well-defined intense Soret and Q-bands in the visible region, and the intensity and the position of the absorption maxima were dependent on the number and the nature of the heteroatoms present in the cavity. The solid-state structures of sapphyrins 8 and 9 show small deviations from planarity with formation of supramolecular ladders stabilized by weak C−H···S, C−H···Se, and C−H···N hydrogen bonds. 1H NMR studies reveal retainment of supramolecular arrays in solution. The TFA adduct of 8 shows unusual binding in which both the hydroxyl oxygen and the carbonyl oxygen participate, which is reminiscent of metal carboxylate binding and in total contrast to that observed for β-substituted sapphyrins. 1H NMR studies on rubyrins indicate rapid rotation of heterocyclic rings at room temperature, and protonation leads to a decrease in rate of rotation at room temperature. 1H NMR spectra of 10 and 17 in its free base form recorded at −50 °C reveal that the heterocyclic rings are inverted and protonation leads to dramatic ring flipping. However, 11 shows normal structure in the solution. The single-crystal X-ray structures of 10, 11, and 17 show that the heterocyclic rings, thiophene in 10, selenophene in 11, and furan and thiophene in 17, are inverted in the solid state.

A synthetic access to the first members of expanded corroles 1 and 2 is achieved through formation of two direct pyrrole−pyrrole links by an oxidative coupling reaction. Spectroscopic and structural analysis reveal that 1 and 2 are 22Π aromatic macrocycles despite the nonplanar structure and properties resemble that of isocorroles rather than 22Π sapphyrins. Sapphyrin 1 is an example of the simplest possible expanded porphyrin with 22Π electrons. 1 The existence of sapphyrins was been reported long ago, but their rich and diverse chemistry has been explored only recently after the development of efficient synthetic methodologies allowing their preparation in gram quantities. Removal of one meso carbon from the sapphyrin skeleton results in a new 22Π electron macrocycle with two direct pyrrole-pyrrole links. This structural principle is referred to as "smaragdyrin" 2 in the literature. 2,3 The structural relationship between 1 and 2 is analogous to that between a porphyrin and a corrole; therefore, the chemistry of smaragdyrins is expected to resemble that of corroles. 4 Two previous attempts to syn-(1) For the recent reviews and papers on the expanded porphyrins, see: (a) Jasat, A.; Dolphin, D.