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A novel self-complementary nucleoside ((A)T), featuring two complementary nucleobases linked through an ethynyl group has been synthesized. The rigid aromatic nucleobases provided (A)T with a pale-blue fluorescence. Unlike most fluorescent organic molecules, nucleoside (A)T gives enhanced fluorescence in solid state. It exhibits considerably enhanced fluorescence intensity and a remarkable redshift (ca. 70 nm) in its emission maximum upon an increase in concentration or decrease in temperature as a result of the formation of aggregates stabilized through hydrogen bonding and π-π stacking of well-organized (A) T assemblies; these interactions are also evident in the solid-state structure, determined by X-ray crystallography. DFT calculations supported the preference of such aggregation processes., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We have carried out density functional theory calculations as well as experiments to rationalize the catalytic activity of various phosphine-copper complexes for the hydroboration of styrene with pinacolborane. The experimentally obtained catalytic efficiency was explained on the basis of activation barriers for consecutive reaction mechanism steps as well as by molecular orbitals and charges in the transition state. Bidentate ligands were found to be more efficient than monodentate ligands for catalytic activity. Bidentate ligands make the reactant complexes less stable than monodentate ligands due to steric hindrance. This information could be usefully utilized for new catalysts design. The calculated kinetic data were consistent with the experimental conversion efficiency in a process that was hypothesizd to undergo the addition of Cu-H to styrene as the rate-limiting step. From the electronic distribution of the HOMO and the charge of the copper atom in the transition state, it was found that styrenes substituted with electron withdrawing groups would give higher conversions, and the catalytic efficiency could be increased with properly designed electron-donating ligands for the copper catalyst complex.