Design and synthesis of molecular assemblies which exhibit aggregation-induced emission (AIE) have attracted persistent attention in recent years. However, studies on the impact of the substitution position in isostructural molecules to regulate aggregation-induced emission (AIE) or convert aggregation-caused quenching (ACQ) to AIE have not been reported to date. In the present study, aggregation properties of two isostructural fluorophores viz. (E)-4-(2-(anthracen-9-yl)vinyl)benzonitrile (p-AnCN) and (E)-3-(2-(anthracen-9-yl)vinyl)benzonitrile (m-AnCN), with different substitution positions have been evaluated. It was observed that m-AnCN exhibits an ACQ behavior, whereas, p-AnCN exhibits enhanced emission upon aggregation. Upon aggregation, c.a. 1.4-fold decrease in luminescence quantum yield has been observed for m-AnCN, whereas, c.a. 11-fold enhancement in luminescence quantum yield has been achieved for p-AnCN. Results from the study indicate that absence of interplay between the excited states from a dark Intramolecular Charge Transfer (ICT) state to Locally Excited state (LE) in m-AnCN is the primary reason behind the observed difference in the emission properties of the aggregates. Thus, modulation of ACQ-AIE properties has been achieved using isostructural organic fluorophores, which in turn can be used as a versatile strategy to achieve AIE-luminophores. Further, the AIE active p-AnCN aggregates have been utilized to generate three-component white light emission with CIE coordinates of (0.33, 0.33).
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