On the relationship between molecular geometry and excited-state properties of 9-anthrylalkenes

Abstract

The excited-state properties of a series of 1-substituted and 1,1-disubstituted 2-(9-anthryl)alkenes have been investigated in terms of their fluorescence spectra and photochemical isomerizations. Large Stokes shifts of up to 10000 cm"1 between absorption and emission maxima are attributed to geometrical differences between the ground state and the emitting excited state. The [cis]: [trans] ratio of the photostationary state was found to depend markedly on the nature of the 1-substituent. Photochemical isomerization of 1,3-and l,5-bis(9anthryl)-substituted trans olefins results in the formation of intramolecular [4 + 4it] or [4 + 2x] cycloaddition products. The cycloaddition reactions of carbonyl-substituted anthracenes are suggested to involve the triplet excited state.

Diethyl 2-anthracen-9-ylmethylenemalonate

“…Compounds containing an anthracene ring system show important photochemical and physical properties (Endo et al, 1997;Becker & Andersson, 1983). Intramolecular charge transfer between the anthracene moiety and attached groups has been deeply explored by absorption and emission spectra (Becker & Andersson, 1983). The title compound contains an anthracene ring system to which an ethylene bond is attached at position 9.…”

“…Intramolecular charge transfer between the anthracene moiety and attached groups has been deeply explored by absorption and emission spectra (Becker & Andersson, 1983). The title compound contains an anthracene ring system to which an ethylene bond is attached at position 9.…”

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The structure determination of the title compound, C 22 H 20 O 4 , was undertaken in order to establish its the conformation, especially the angle between the aromatic ring system and the ethylene moiety, which turned out to be 68.06 (5)°.

CommentCompounds containing an anthracene ring system show important photochemical and physical properties (Endo et al, 1997;Becker & Andersson, 1983). Intramolecular charge transfer between the anthracene moiety and attached groups has been deeply explored by absorption and emission spectra (Becker & Andersson, 1983). The title compound contains an anthracene ring system to which an ethylene bond is attached at position 9.

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Structures and photochemical reactions of 1-(9-anthryl)-2-aroylethylenes: competing cis–trans isomerization and skeletal rearrangement

“…The absorption spectra of cis-(I), cis-(III) and cis-(IV) are similar to each other, exhibiting fine structure characteristics for the So-S~ transition of the anthracene chromophore. According to Becker & Andersson (1983), conjugation of the substituent attached to the C-~C double bond with the 9-vinylanthracene chromophore causes loss of fine structure in the absorption spectrum. As mentioned above, the anthracene plane makes a large dihedral angle with the enone moiety, which should decrease the conjugation and bring about the fine structure of the absorption spectrum.…”

Characterization and spectroelectrochemical properties of a binuclear trans,trans-bis(ferrocenylidene)acetone [(C5H5)Fe(C5H4CHCH)]2CO

“…In the non-complexed state, they generally exhibit rich photochemical (9)(10)(11)(12), electrochemical (12)(13)(14), and photoluminescent properties (1 2). Recent resonance Raman, UV-VIS, and emission spectroscopic investigations of the binuclear Pd(0)-and Pt(0)-dibenzylideneacetone complexes reveal the metal-to-ligand charge transfer (MLCT) character of the lowest singlet and triplet excited states (15).…”