A Self-Complementary Nucleoside: Synthesis, Solid-State Structure, and Fluorescence Behavior

Abstract

A novel self-complementary nucleoside (T-A), featuring two complementary nucleobases linked through an ethynyl group has been synthesized. The rigid aromatic nucleobases provided T-A with a pale-blue fluorescence. Unlike most fluorescent organic molecules, nucleoside T-A 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 pi-pi stacking of well-organized T-A 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.