In Situ Methylation Transforms Aggregation‐Caused Quenching into Aggregation‐Induced Emission: Functional Porous Silsesquioxane‐Based Composites with Enhanced Near‐Infrared Emission

Abstract

Methylation of TPA‐DCM (2‐(2,6‐bis‐4‐(diphenylamino)stryryl‐4H‐pyranylidene)malononitrile) that exhibits aggregation‐caused quenching (ACQ) results in the fluorophore M‐TPA‐DCM (2‐(2,6‐bis((E)‐4‐(di‐p‐tolylamino)‐styryl)‐4H‐pyran‐4‐ylidene]malononitrile) that shows aggregation‐induced emission (AIE) and NIR fluorescence and has a conjugated “D‐π‐A‐π‐D” electronic configuration. Friedel‐Crafts reaction of TPA‐DCM and octavinylsilsesquioxane (OVS) resulted in a family of porous materials (TPAIEs) that contain the M‐TPA‐DCM motif and show large Stokes shifts (180 nm), NIR emission (670 nm), tunable porosity (SBET from 160 to 720 m2 g−1, pore volumes of 0.13–0.55 cm3 g−1), as well as high thermal stability (400 °C, 5 % mass loss, N2). As a simple test case, one of TPAIE materials was used to sense Ru3+ ions with high selectivity and sensitivity.Small changes with big effect: Methylation of TPA‐DCM (2‐(2,6‐bis‐4‐(diphenylamino)stryryl‐4H‐pyranylidene)malononitrile), which exhibits aggregation‐caused quenching (ACQ), gives the fluorophore M‐TPA‐DCM (2‐(2,6‐bis((E)‐4‐(di‐p‐tolylamino)‐styryl)‐4H‐pyran‐4‐ylidene)malononitrile) that shows aggregation‐induced emission (AIE) and NIR fluorescence. Friedel‐Crafts reaction of TPA‐DCM with octavinylsilsesquioxane produces a family of porous composites (TPAIEs) with the M‐TPA‐DCM motif. TPAIEs show large Stokes shifts, NIR emission, tunable porosity as well as high thermal stability.