Benzo[d]imidazole Based Organic Photocatalyst for Trifluoromethylation of Polyaromatic Hydrocarbons

The surge of organofluorine compounds, particularly incorporation of a -CF₃ group in organic molecules for pharmaceutical and materials sectors demands development of a mild and regioselective trifluoromethylation route. In this work, procarbenic benzo[d]imidazole based organic photocatalysts C1 and C2 enabled mild, regioselective trifluoromethylation, addressing the demand of -CF₃ incorporation in polyaromatic hydrocarbons (PAHs). These photocatalysts showed intense ligand-to-ligand charge transfer absorption in the UV (λ_abs ∼ 280 nm) and low-negative quasi-reversible reductions (E_red = -0.91 and -1.11 V vs SCE for C1 and C2). Both emitted deep-blue ¹LC fluorescence at RT (375-390 nm) and acted as strong photo-oxidants (E_C(II)*/C(I) ∼ 2.70 V vs SCE), enabling efficient metal- and additive-free mono(trifluoromethylation) of polyaromatic hydrocarbons.