Direct Synthesis of Dipyrrolyldipyrrins from S N Ar Reaction on 1,9-Dihalodipyrrins with Pyrroles and Their NIR Fluorescence "Turn-On" Response to Zn 2 .

A set of dipyrrolyldipyrrins have been efficiently synthesized from a direct S _N Ar reaction on 1,9-dihalodipyrrins with pyrroles and show intense absorption in the NIR region (650-800 nm, as HCl salts). Substituents on both 1,9-dihalodipyrrins and pyrroles greatly affected the reactivity of this S _N Ar reaction and the absorption properties of the resultant dipyrrolyldipyrrins. These dipyrrolyldipyrrins show sensitive and selective "turn-on" fluorescence response toward Zn ²⁺ .