Synthesis of V-shaped Thiophene Based Rotor-Stilbene: Substituent Dependent Aggregation and Photophysical Properties.

ABSTRACT

Thiophene core V-shaped rotor-stilbene derivatives have been synthesized utilizing two-fold Heck coupling reaction. These compounds are blue emitters with moderate quantum yield in dilute solution. Rotor nature of the synthesized stilbenes supports aggregation induced emission (AIE) behaviour and they show substituent dependent emission behavior in aggregate state. In presence of donating groups (e.g., tert-butyl, methoxy, diphenylamine group) in stilbenes, they exhibit AIE property. But with the introduction of electron withdrawing group (nitro group), they shows aggregation caused quenching (ACQ) behavior. Different types of nano-aggregates formation is observed in aggregated state, which was confirmed by dynamic light scattering (DLS) and scanning electron microscopy (SEM) studies. The details photophysical (absorption, fluorescence, and lifetime), electrochemical property (cyclic voltammetry) and thermal stability have been investigated. Optimized structure, energy and electronic distribution of molecular orbitals have been studied by theoretical calculation.