Studies on Metastable States of Porphyrins. II. Spectra and Decay Kinetics of Tetraphenylporphine, Zinc Tetraphenylporphine and Bacteriochlorophyll1
01 May 1960-Journal of the American Chemical Society (American Chemical Society)-Vol. 82, Iss: 10, pp 2407-2411
TL;DR: In this article, the flash technique used earlier to study the metastable states of chlorophyll was applied to tetraphenylporphine, zinc tetramerphine and bacteriochlorophyll in toluene and pyridine solution.
Abstract: The flash technique used earlier to study the metastable states of chlorophyll was applied to tetraphenylporphine, - zinc tetraphenylporphine, and bacteriochlorophyll in toluene and pyridine solution. The spectra all show a main band just below the Soret peak, as well as other regularities. The decay law is again --dC*/dt = k1C* + k2(C*)2 + The respective rate constants for all the compounds are almost the same, except for a much faster first-order decay in bacteriochlorophyll. Finally, little or no flash-bleaching is observed with the Cu2+, Co2+, and Ni2+ complexes of tetraphenylporphine.
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TL;DR: In this article, the absorption spectra of metal porphyrins derived from the basic skeleton are discussed in terms of a four-orbit model, that is intensity changes and energy shifts are related to the properties of two top filled and two lowest empty pi orbitals.
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TL;DR: In this article, a four-orbital model was proposed to explain the visible and Soret bands of the porphin spectrum, where the lowest two pairs of excited configurations are accidentally degenerate and the extensive interaction between them accounts for the great intensity of the Soret and the relative weakness of the visible bands; interaction with higher configurations is negligible.
420 citations
TL;DR: It is discovered that zinc porphyrins were able to selectively activate photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization of trithiocarbonate compounds under visible light irradiation over a broad range of wavelengths.
Abstract: The use of metalloporphyrins has been gaining popularity particularly in the area of medicine concerning sensitizers for the treatment of cancer and dermatological diseases through photodynamic therapy (PDT), and advanced materials for engineering molecular antenna for harvesting solar energy. In line with the myriad functions of metalloporphyrins, we investigated their capability for photoinduced living polymerization under visible light irradiation over a broad range of wavelengths. We discovered that zinc porphyrins (i.e., zinc tetraphenylporphine (ZnTPP)) were able to selectively activate photoinduced electron transfer–reversible addition–fragmentation chain transfer (PET-RAFT) polymerization of trithiocarbonate compounds for the polymerization of styrene, (meth)acrylates and (meth)acrylamides under a broad range of wavelengths (from 435 to 655 nm). Interestingly, other thiocarbonylthio compounds (dithiobenzoate, dithiocarbamate and xanthate) were not effectively activated in the presence of ZnTPP. Th...
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TL;DR: In this paper, a decrease of light transmission with increasing excitation intensity was observed in tetraphenylporphyrin/toluene solutions irradiated with 80 ps pulses at λ=532 nm.
277 citations