Anthracene moiety

Flegel, M. Lukeman, M. Huck, L. Wan, P. Photoaddition of water and alcohols to the anthracene moiety of 9-(2 -hydroxyphenyl)anthracene via formal excited state intramolecular proton transfer. J. Am. Chem. Soc. 2004, 126, 7890-7897. 

Basaric, N. Wan, P. Competing excited state intramolecular proton transfer pathways from phenol to anthracene moieties. J. Org. Chem. 2006, 71, 2677-2686. 

Carboxylic acids can be detected fluorimetrically by attaching them to an anthracene moiety 145 ... 

They observed a constant quantum yield of fluorescence (Or = 0.3) for all members of the series independent of whether the anthracene moiety absorbed and emitted the energy or the naphthalene moiety absorbed the energy and transferred it to the anthracene moiety. Thus at these short distances singlet energy transfer is 100% efficient. 

The first chemiluminescent paracyclophanes have been described recently 208> the compounds 138 and 139 both contain a phthalhydrazide group as that part of the molecule producing the excitation energy which is transferred to the substituted benzene resp. anthracene moiety. 139 chemiluminesces with about double the amount of 2.3-anthracene dicarboxylic hydrazide on oxidation by oxygen/potassium tert. butoxide... 

In calixarene-based compound M-8 (Figure 10.28), bearing four anthracene moieties on the lower rim, some changes in fluorescence intensity were observed on binding of alkali metal ions but no excimer emission was detected. Quenching of the fluorescence by Na+ may arise from interaction of four anthracene residues brought in closer proximity to one another enhancement of fluorescence by K+ is difficult to explain. 

Heating the anthracene monoadduct in toluene affords the component molecules [1,8], which demonstrates a facile retro-Diels-Alder reaction. A thermal gravimetric analysis (TGA) of solid Cgo(anthracene) shows a cleavage of the anthracene moiety... 

Figure 5. Schematic view of parallel aligned anthracene moieties in (a) meso and (b) d,l-bis-9-anthrylmethyl ethers 24.

The molecular geometry of the parent cis-1,2-di-9-anthrylethylene 38a has not been established by X-ray diffraction, but crystal structure analyses of several 1,2-substituted cis-dianthrylethylenes 38 are available. Depending on the spatial demand of the substituents R and R, the planes of the anthracene moieties are twisted out of the plane of the ethylene by 59-84° [80],... 

In a low quantum yield process ( = 0.0008 see Figure 11), singlet excited ct s-l-(9-anthryl)-2-benzoylethylene 66a isomerizes by a skeletal rearrangement to give furano-annelated 5H-dibenzocycloheptene 67 in excellent chemical yield. Various derivatives of 65a/66a, in which either the phenyl ring or the anthracene moiety are substituted, have been found to rearrange... 

Energy of the singlel excited slate of anthracene moiety. bExciplex emission not included. 

In polar solvents, the quantum yields for the emission from the locally excited state of anthronyl-anthracenes 98 and 99 decrease drastically (see Tables 20 and 21), and a structureless, red-shifted exciplex emission is observed (see Figure 23). For the parent compound 98a in dichloromethane, for example, the quantum yield of emission from the exciplex state is 0.012, but that of emission from the locally excited state has decreased to 0.00058 (cf. Tables 20 and 22). Thus, intramolecular exciplex formation between the photoexcited anthracene moiety and the aromatic ketone in its electronic ground state represents the major mode of deactivation in polar solvents. 

Enhancement of fluorescence due to the complexation of metal ions with fluoroionophores has been used as a well-precedented technique to analyze for the presence of metal ions [189-191], A number of studies have reported chelating fluorophores whose emission spectra change upon the addition of metal ions [192-198]. One remarkable result of this emission intensity enhancement is shown in Scheme 23, where the chelation of zinc chloride to 9,10-bis(((2-(dimethylamino)ethyl)methylamino)methyl)anthracene drastically enhances the observed fluorescence by a factor greater than 1000-fold [199], In the absence of Zn2+, the singlet excited state of anthracene moiety is strongly quenched by intramolecular photoinduced electron transfer from the amine to the anthracene moiety. The complex formation of Zn2+ with the amine moiety may result in the largely positive shift of the one-electron oxidation potential. Thus, intramolecular photoinduced electron transfer is strongly suppressed by the complexation of the amine moiety with Zn2+,... 

Abstract We describe mechanochromic and thermochromic photoluminescent liquid crystals. In particular, mechanochromic photoluminescent liquid crystals found recently, which are new stimuli-responsive materials are reported. For example, photoluminescent liquid crystals having bulky dendritic moieties with long alkyl chains change their photoluminescent colors by mechanical stimuli associated with isothermal phase transitions. The photoluminescent properties of molecular assemblies depend on their assembled structures. Therefore, controlling the structures of molecular assemblies with external stimuli leads to the development of stimuli-responsive luminescent materials. Mechanochromic photoluminescent properties are also observed for a photoluminescent metallomesogen and a liquid-crystalline polymer. We also show thermochromic photoluminescent liquid crystals based on origo-(/ -phenylenevinylene) and anthracene moieties and a thermochromic photoluminescent metallocomplex. 

Dithienylethene derivatives can also be linked to a fluorescent bisfphe-nylethynyl)-anthracene residue, showing that the irradiation at 313 ran, able to give the closed form of the photochromic device, the fluorescence of the anthracene moiety at 530 nm is efficiently quenched (Of < 0.001) (01JCS(CC)711). 

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