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Acid-catalyzed condensations between a dipyrrylmethane and a pyrrole bisacrylaldehyde gave an unusual stretched sapphyrin structure together with a hexaphyrin byproduct. A diazulihexaphyrin was prepared similarly. The highly diatropic sapphyrin analogue was isolated as a dication and was characterized by X-ray crystallography.
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Zhang et al. (2009) studied this question.
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