Nano self-aggregation of new benzotriazole-coumarin dyads displaying strengthened emission with huge Stokes shift

New benzotriazole-coumarin dyads (C1-C4) were synthesized to study π-π intermolecular interaction and intra/inter molecular hydrogen bond effects on producing molecular self-aggregates of organic dyes in mixed DMF/H2O solvents. The results show that wire shape nano self-aggregates of C1 are formed basing on strong π-π interaction and hydrogen bond in mixed DMF/H2O solution at 12 h aggregation time, exhibiting strengthened fluorescence emission with huge Stokes shift. In contrast, C2, C3 and C4 with weak π-π interaction or lack of hydrogen bond do not yield nano molecular aggregates.