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At least 163 records · Page 9Linked to original sources
PubMed2006

Acylation of nickel meso-tetraarylporphyrins: porphyrin to corrole ring contraction and formation of seco-porphyrins.

Friedel-Crafts acylation of nickel meso-tetraarylporphyrins with aryl anhydrides, followed by air oxidation in the presence of pyridine, DMAP, and excess anhydride, produced corroles in 8-21% yields. Other products include a porphyrinic ketone, an additional corrole whose bridge has been retained as an acyl group attached to a pyrrole, and a lactone resulting from the insertion of an oxygen atom into an alpha,beta-pyrrole bond. The ring contraction is best explained by a pinacolic rearrangement reminiscent of the one taking place in the formation of corrinoids, a benzoyloxy group replacing the acetic side chain found in the natural products.

Journal Article↗
PubMed2005

Synthesis and photoinduced electron transfer processes of rotaxanes bearing [60]fullerene and zinc porphyrin: effects of interlocked structure and length of axle with porphyrins.

Three rotaxanes, with axles with two zinc porphyrins (ZnPs) at both ends penetrating into a necklace pending a C60 moiety, were synthesized with varying interlocked structures and axle lengths. The intra-rotaxane photoinduced electron transfer processes between the spatially positioned C60 and ZnP in rotaxanes were investigated. Charge-separated (CS) states (ZnP*+, C60*-)rotaxane are formed via the excited singlet state of ZnP (1ZnP*) to the C60 moiety in solvents such as benzonitrile, THF, and toluene. The rate constants and quantum yields of charge separation via 1ZnP decrease with axle length, but they are insensitive to solvent polarity. When the axle becomes long, charge separation takes place via the excited triplet state of ZnP (3ZnP*). The lifetime of the CS state increases with axle length from 180 to 650 ns at room temperature. The small activation energies of charge recombination were evaluated by temperature dependence of electron-transfer rate constants, probably reflecting through-space electron transfer in the rotaxane structures.

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PubMed2005

Cofacial porphyrin-ferrocene dyads and a new class of conjugated porphyrin.

A porphyrin-ferrocene dyad has been synthesized in which there is close face-to-face contact between the two aromatic systems, providing a model for heterobimetallic polymers based on the same repeating unit. Attempts to synthesize the 2:1 adduct instead led to a remarkable intramolecular Heck-type cyclization which planarizes the system and extends the conjugation. [structure: see text]

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