Arene-Perfluoroarene-Enabled Electrostatic Modulation in Organic Porous Photocatalysts for Ni/Photoredox C-N Coupling.

Abstract

How molecular connectivity can tune photoresponsive local electrostatics in porous organic photocatalysts lacking long-range order remains unclear. Here, we use arene-perfluoroarene (AP)-based constitutional design to examine this relationship in 4CzIPN-derived porous photoredox polymers. Carbazole and perfluorocarbazole units are connected through ortho-, meta-, and para-linked biphenyl bridges. Kelvin probe force microscopy reveals local light-induced contact potential difference (CPD) shifts of 27.1, 18.3, 5.0, and 4.3 mV for o-CBCP, m-CBCP, p-CBCP, and the AP-free control P(4Cz), respectively. o-CBCP also exhibits a stronger surface photovoltage response than P(4Cz) and the lowest fitted intermediate-frequency resistance under 425 nm blue LED illumination. In a catalyst-discriminating Ni/photoredox C-N coupling reaction, product yields follow the same order as the local CPD shifts. With 0.2 mg of photocatalyst on a 0.2 mmol reaction scale, o-CBCP affords the product in good yield, whereas P(4Cz) gives only trace product. These findings identify linkage geometry as a molecular handle for tuning photoresponsive local electrostatics and catalytic behavior in disordered porous polymer photocatalysts.

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