Synthesis and complementary self-association of novel lipophilic π-conjugated nucleoside oligomers

A series of lipophilic nucleosides comprising natural and non-natural bases that are pi-conjugated to a short oligophenylene-ethynylene fragment has been synthesized. These bases comprise guanosine, isoguanosine, and 2-aminoadenosine as purine heterocycles, and cytidine, isocytosine and uridine as complementary pyrimidine bases. The hydrogen-bonding dimerization and association processes between complementary bases were also studied by H-1 NMR and absorption spectroscopy in order to obtain the relevant association constants.