82565-66-0Relevant articles and documents
Towards More Photostable, Brighter, and Less Phototoxic Chromophores: Synthesis and Properties of Porphyrins Functionalized with Cyclooctatetraene
Ostapko, Jakub,Gorski, Aleksander,Buczyńska, Joanna,Golec, Barbara,Nawara, Krzysztof,Kharchenko, Anastasiia,Listkowski, Arkadiusz,Ceborska, Magdalena,Pietrzak, Mariusz,Waluk, Jacek
, p. 16666 - 16675 (2020)
Free base and zinc porphyrins functionalized with cyclooctatetraene (COT), a molecule known as a good triplet-state quencher, have been obtained and characterized in detail by structural, spectral, and photophysical techniques. Substitution with COT leads to a dramatic decrease of the intrinsic lifetime of the porphyrin triplet. As a result, photostability in oxygen-free solution increases by two to three orders of magnitude. In non-degassed solutions, improvement of photostability is about tenfold for zinc porphyrins, but the free bases become less photostable. Similar quantum yields of photodegradation in free base and zinc porphyrins containing the COT moiety indicate a common mechanism of photochemical decomposition. The new porphyrins are expected to be much less phototoxic, since the quantum yield of singlet oxygen formation strongly decreases because of the shorter triplet lifetime. The reduction of triplet lifetime should also enhance the brightness and reduce blinking in porphyrin chromophores emitting in single-molecule regime, since the duration of dark OFF states will be shorter.
Synthesis and solid-state polymerization of triyne and enediyne derivatives with similar π-conjugated structures
Mizukoshi, Kana,Okada, Shuji,Kimura, Tatsumi,Shimada, Satoru,Matsuda, Hiro
experimental part, p. 1028 - 1037 (2009/04/13)
Three diacetylene monomer model compounds with similar π-conjugation systems, 10-phenyl-5,7,9-decatriynyl W-phenylcarbamate (1), (E)-10-phenyldec-9- en-5,7-diynyl /V-phenylcarbamate (2), and (E)-10-phenyldec-5-en-7,9-diynyl N-phenylcarbamate (3), were synthesized and their properties and solid-state polymerization were investigated. Based on the absorption spectra of the monomers, it was found that the conjugation effect of a double bond was different from that of a triple bond in solution. Monomers 1,2, and 3 gave one, two, and five crystal forms, respectively, of which 1 and one of the crystal forms of 2 (2a) could be polymerized in the solid state. The conversions after y-ray irradiation (1 MGy dose) were 53% and 20%, respectively. The longest-wavelength absorption maxima of the polymers prepared from 1 and 2a were 645 and 655 nm, respectively. The polymerizable crystals 1 and 2a were found to have layered monomer structures with spacing of 3.1-3.6 nm. Based on solid-state 13CNMR spectra, the polymerization sites of 1 were determined to be the 1,4- and 3,6-positions with respect to the phenyl ring, and that of 2a was determined to be the 3,6-position with respect to the phenyl ring.
PMHS-mediated couplings of alkynes or benzothiazoles with various electrophiles: Application to the synthesis of (-)-akolactone A
Gallagher, William P.,Maleczka Jr., Robert E.
, p. 6775 - 6779 (2007/10/03)
Polymethylhydrosiloxane (PMHS) in combination with CsF facilitates the cross-coupling of alkynes or benzothiazoles with an array of vinyl, styryl, and aryl halides or nonaflates as well as acid chlorides. Experimental and spectroscopic evidence indicates that these reactions involve the in situ generation of a siloxyl intermediate. These cross-couplings proceed relatively quickly at room temperature and under amine-free conditions. To demonstrate the applicability of the method, a total synthesis of the cyctotoxic butanolide (-)-akolactone A was carried out.
