0000000000230824
AUTHOR
Chunmei Gao
Structure Determination of Photoproducts of Anthracenes with (Arylmethoxymethyl) Sidechains
Irradiation of 9-(arylmethoxymethyl)anthracenes 3 leads either to a cyclomer and cyclodimer mixture (3a 4a,5a), to selectively formed dimers (3b 5b), or a selectively formed cyclomer (3c 4c). The [4π+4π]cyclodimerization is under the conditions used a regioselective head-to-tail process. In the crystals of the dimers 5a,b, the sidechains are attached in an antiperiplanar position related to the CC bonds generated in the dimerization. In solutions, however, the structures consist of three rotamers the equilibration of which was studied by temperature-dependent NMR spectra. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Protonation and rearrangement of the tricyclo[4.2.2.22,5]dodeca-3,7,9,11-tetraene scaffold
The biplanemers 2a,b contain enol ether substructures, which permit facile protonations of the π electron system. The subsequent ether cleavage is characterized by rearrangements of the polycyclic scaffold of the carbenium ions or the electroneutral primary products. Apart from the expected products 3a and 5a, a series of unexpected ketones and diketones (4a′, 9b, 10b, 11b, and 12b) were obtained.
Optical Switching and Antenna Effect of Dendrimers with an Anthracene Core
Dendrimers 6G(i) (i=1-4) consisting of an anthracene core and Fréchet dendrons which are attached via a CH(2)OCH(2) chain in the 9-position undergo quantitative and completely reversible intramolecular [4pi+4pi] cycloaddition. The process can be monitored by absorption and fluorescence measurements. The Fréchet dendrons act as an energy funnel that collects and focuses the photon energy but does not change the photostationary states, which for both directions are completely on the product side when the separate chromophores are selectively irradiated. The quantum yields of anthracene fluorescence and of singlet energy transfer from the dendrons to the core were studied as a function of dend…
CCDC 290378: Experimental Crystal Structure Determination
Related Article: Derong Cao, Sheyang Xu, Chunmei Gao, H.Meier|2006|Tetrahedron Lett.|47|2759|doi:10.1016/j.tetlet.2006.02.074
CCDC 634268: Experimental Crystal Structure Determination
Related Article: S.Dobis, D.Schollmeyer, Chunmei Gao, Derong Cao, H.Meier|2007|Eur.J.Org.Chem.|2007|2964|doi:10.1002/ejoc.200700140
CCDC 634267: Experimental Crystal Structure Determination
Related Article: S.Dobis, D.Schollmeyer, Chunmei Gao, Derong Cao, H.Meier|2007|Eur.J.Org.Chem.|2007|2964|doi:10.1002/ejoc.200700140