Cyclic butadiyne-linked porphyrin(2.1.2.1) oligomers
Abstract
Cyclic butadiyne-linked porphyrin(2.1.2.1) oligomers are synthesized from 5,16-diethynylporphyrin(2.1.2.1) by Glaser–Hay coupling. Porphyrin(2.1.2.1) forms a bent structure which gives advantages for making cyclic structure without templating molecules. We isolated cyclic trimer and tetramer and characterized them by MALDI-TOF-MS and 1H NMR spectroscopy, theoretical calculations, UV-vis absorption and fluorescence spectra and cyclic voltammetry. The cyclic structure mainly affects the reduction potentials because of expansion of π-conjugations through butadiyne-linkages to stabilize their LUMOs.
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Dedicated to Professor Atsuhiro Osuka on the occasion of his 65th birthday.
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