Tracking the formation of supramolecular G-quadruplexes via self-assembly enhanced emission.

We report the synthesis and self-assembly of two lipophilic 2'-deoxyguanosine (G) derivatives whose fluorescence intensity is modulated by self-assembly into supramolecular G-quadruplexes (SGQs). Whereas both derivatives self-assemble isostructurally, one shows up to 100% emission enhancement while the other shows an initial enhancement, followed by 10% quenching. Thus, the rotational restrictions resulting from self-assembly are enough to induce significant changes in emission, but it is critical to consider the specific interactions between fluorophores since they will determine the ultimate emission signature.

A photoresponsive supramolecular G-quadruplex.

Photoirradiation of a hexadecameric supramolecular G-quadruplex leads to a diastereoselective [2 + 2] cyclodimerization of half of its constituent subunits, which in turn shifts the equilibrium toward the formation of a precise heteromeric octamer.