ORGN 518 |
| Donor–acceptor purines with various donor groups in the C(2)- and C(6)-positions of the heterocycle and either a nitrile or methyl ester acceptor in the C(8)-position have been efficiently prepared. Central to the synthesis of the nitrile derivatives is an optimized palladium-catalyzed cyanation reaction at C(8) beginning from the appropriate bromide precursor. Subsequent methanolysis provides the corresponding ester derivatives. The absorption and luminescence properties of the compounds have been studied in organic solution where relatively high fluorescence quantum yields are measured (e.g., for D1 = NH2, D2 = N(CH3)2, and A = CN in dichloromethane: λex = 320 nm, λex = 370 nm, and ΦF = 0.17). Crystal structures of two isomeric nitriles with interchanged donor groups allow direct comparison of hydrogen bonding and antiparallel π-stacking patterns as well as bond lengths in the solid state.
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Heterocycles, Aromatics, Metal-Mediated Reactions and Syntheses, Materials, Devices, and Switches
8:00 PM-10:00 PM, Wednesday, 29 March 2006 Georgia World Congress Center -- Ex. Hall B4, Poster
Division of Organic Chemistry |
