- Photochemical synthesis and electronic spectra of fulminene ([6]phenacene)
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Facile synthesis of fulminene ([6]phenacene) was achieved through the Mallory reaction of 1-(1-naphthyl)-2-(1-phenanthryl)ethene or the 9-fluorenone-sensitized photo-ring-closure of 1-(1-naphthyl)-2-(1-phenanthryl) ethane. The electronic spectral properties of fulminene were investigated for the first time using photoluminescence as well as transient absorption spectroscopy. The spectral features were compared with those of a series of lower phenacene homologs such as phenanthrene ([3]phenacene), chrysene ([4]phenacene), and picene ([5]phenacene). For the [n]phenacene series, both the fluorescence and phosphorescence bands linearly red-shifted with an increase in the number of the benzene rings (n). Trends in the energy levels of the excited singlet (E S) and the triplet (E T) states were expressed as E s = -2.6n + 89.1 (kcal mol-1) and E T = -1.8n + 66.2 (kcal mol-1), respectively. In the case of fulminene, laser flash photolysis displayed a transient spectrum with an absorption maximum (λ max T-T) at 675 nm, which was assigned as the triplet fulminene excited state. The λ max T-T values for the [n]phenacene series showed a linear correlation as a function of the ring number n, given by an equation, λ max T-T = 60n + 318 (nm).
- Okamoto, Hideki,Yamaji, Minoru,Gohda, Shin,Sato, Kaori,Sugino, Hisako,Satake, Kyosuke
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- Convenient Phenacene Synthesis by Sequentially Performed Wittig Reaction and Mallory Photocyclization Using Continuous-Flow Techniques
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Various phenacenes possessing chrysene, picene, and fulminene frameworks were prepared by using a continuous-flow synthetic protocol in which Wittig reaction affording diarylethenes and their Mallory photocyclization producing phenacene skeletons were sequentially performed. The Wittig reaction solution, containing the diaryl ethene obtained from an arylaldehyde and an arylmethyltriphenylphosphonium salt, was mixed with an iodine solution in the flow system and, subsequently, the solution was subjected to the photoreaction. Desired phenacenes were obtained with high to moderate chemical yield. For the present protocol, isolation of the intermediary diarylethene, which is the key precursor of the phenacene, is unnecessary. The approach provides a convenient method to supply a variety of phenacene samples, which are needed for initial systematic surveys in material science.
- Okamoto, Hideki,Takahashi, Haruhiko,Takane, Takamitsu,Nishiyama, Yasuhiro,Kakiuchi, Kiyomi,Gohda, Shin,Yamaji, Minoru
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p. 2949 - 2957
(2017/06/27)
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- Efficient synthetic photocyclization for phenacenes using a continuous flow reactor
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The continuous flow reaction technique has been applied to the photocyclization of 1,2-diarylethenes, the so-called Mallory reaction, to afford phenacenes in high chemical yields and efficiencies (114-288mg h-1). The present technique will allow us to produce several grams of phenacenes at a time.
- Okamoto, Hideki,Takane, Takamitsu,Gohda, Shin,Kubozono, Yoshihiro,Sato, Kaori,Yamaji, Minoru,Satake, Kyosuke
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p. 994 - 996
(2014/07/22)
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- Synthesis of substituted [6]phenacenes through Suzuki-Miyaura coupling of polyhalobenzene with alkenylboronates and sequential intramolecular cyclization via C-H bond activation
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A series of substituted [6]phenacenes were synthesized through the Suzuki-Miyaura coupling and intramolecular double cyclization, using a polyhalobenzene and two different alkenylboronates. This methodology provides a direct route to unsymmetrical [6]phenacenes. The physicochemical properties of four [6]phenacenes were evaluated using UV-vis and fluorescence spectroscopies as well as cyclic voltammetry.
- Chang, Ning-Hui,Mori, Hiroki,Chen, Xi-Chao,Okuda, Yasuhiro,Okamoto, Takeru,Nishihara, Yasushi
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supporting information
p. 1257 - 1259
(2013/10/22)
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- A New General Synthesis of Polycyclic Aromatic Compounds Based on Enamine Chemistry
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Alkylation of enamines and enamine salts by benzylic and (β-haloethyl)aryl halides, respectively, followed by acidic cyclodehydration and dehydrogenation provides an efficient synthetic approach to a wide range of polycyclic aromatic compounds of diverse structural types.Specific polycyclic hydrocarbons synthesized by this route include benzo- and benzofluorene, 7H-dibenzo-, 13H-dibenzo-, and 13H-dibenzofluorene, 15H-tribenzofluorene, dibenzochrysene, benzopentaphene, indenofluorene, fluorenofluorene, octahydrodibenzanthracene, dibenzanthracene, octahydrodibenzanthracene, dibenzanthracene, picene, benzopicene, 1H-benzaceanthrylene, and 4H-cyclopentachrysene.This method with appropriate modifications appears to be potentially broader in scope than established traditional methods of polycyclic hydrocarbon synthesis.
- Harvey, Ronald G.,Pataki, John,Cortez, Cecilia,Raddo, Pasquale Di,Yang, ChengXi
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p. 1210 - 1217
(2007/10/02)
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