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\u2005nm), NIR emission (670\u2005nm), tunable porosity (SBET from 160 to 720\u2005m2 \u2009g-1 , pore volumes of 0.13-0.55\u2005cm3 \u2009g-1 ), as well as high thermal stability (400\u2009°C, 5\u2009% mass loss, N2 ). As a simple test case, one of TPAIE materials was used to sense Ru3+ ions with high selectivity and sensitivity.