G. Demunno et al., 21,23-DITHIAPORPHYCENE - THE 1ST AROMATIC SULFUR-CONTAINING SYSTEM WITH PORPHYCENE STRUCTURE, Tetrahedron, 49(31), 1993, pp. 6863-6872
A porphycene analogue where two nitrogen atoms have been replaced with
sulfur has been prepared from 2-(2-thienyl)-1H-pyrrole. Its X-ray cry
stallographic data, UV/VIS and NMR spectroscopic properties proved the
18 pi electrons aromaticity of the system, like porphycene.