Supramolecular helical self-assemblies and large stokes shift in 1-(2-cyanophenyl)piperazine and 4-piperidinopiperidine bis-substituted tetracyanoquinodimethane fluorophores

• Utilization of 1,2-CPP and 4-PP lead to interactions of type such as H-bonding, π–π, electrostatic and Van der Waals.
• Supramolecular helical self-assemblies and large stokes shift observed in 1,2-CPP and 4-PP bis-substituted TCNQ's.
• Impact of 1,2-CPP and 4-PP resulted in the enhancement of solution and solid state fluorescence with green emission.
• Scanning electron microscopy reveals dendrites, microspheres and micro rings.

Heterocyclic building blocks such as 1-(2-cyanophenyl)piperazine (1,2-CPP) and 4-piperidinopiperidine (4-PP) are very well known in oncological medicines like platins and camptothecins. Utilization of 1,2-CPP and 4-PP in the reaction with tetracyanoquinodimethane (TCNQ) produced two latest compounds, bis (1,2-cyanophenylpiperizino)dicyanoquinodimethane (1,2-CPPDQ) [1] and bis-(4-piperidinopiperidino)dicyanoquinodimethane (4-PPDQ)[2]. Compounds 1 and 2 showed very striking and impetuous results. Both compounds exhibited helical supramolecular assemblies, high fluorescence in their solid state and as well large stokes shift of about ∼95 nm. Quantum yield of solids was 14 times elevated than their solutions. Scanning electron microscope images revealed microstructures of dendrites, spheres and ring like morphologies.