Novel guanosine-cytidine dinucleoside that self-assembles into a trimeric supramolecule

[reaction: see text] Synthesis and assembly studies of a guanosine-cytidine dinucleoside 1 that self-assembles into a trimeric supramolecule (I) are presented. Dinucleoside 1 was obtained by utilizing two consecutive palladium-catalyzed cross-coupling reactions. Ensemble I was analyzed by ESI-MS, NMR spectroscopies, size exclusion chromatography (SEC), and vapor pressure osmometry (VPO).     

Hydrogen-bond-mediated photoinduced electron-transfer: novel dimethylaniline-anthracene ensembles formed via Watson-Crick base-pairing.

The synthesis of a new, noncovalent anthracene-dimethylaniline dyad (ensemble I) held together via guanosine-cytidine Watson-Crick base-pairing interactions is reported. Upon excitation at 420 nm, photoinduced electron-transfer from the dimethylaniline donor to the singlet excited state of the anthracene acceptor occurs, as inferred from a combination of time-resolved fluorescence quenching and transient absorption measurements. In toluene at room temperature, the rate constants for photoinduced intraensemble electron-transfer and subsequent back-electron-transfer (charge recombination) are k(CS) = (3.5 +/- 0.03) x 10(10) s(-1) and k(CR) = (1.42 +/- 0.03) x 10(9) s(-1), respectively.