Aggregation-Induced Emission in a Hyperbranched Poly(silylenevinylene) and Superamplification in Its Emission Quenching by Explosives

A silicon-containing hyperbranched polymer (hb-P1/2) with sigma*-pi* conjugation was prepared in a good yield and high molecular weight by rhodium-catalyzed alkyne polyhydrosilylation of 1,2-bis(4-ethynylphenyl)-1,2-diphenylethene (1) with tris(4-dimethylsilylphenyl)amine (2). The polymer was thermally stable, losing merely 5% of its weight when heated to 445 C. Whereas hb-P1/2 was weakly luminescent when molecularly dissolved, it became highly emissive when supramolecularly aggregated, showing an aggregation-induced emission (ATE) phenomenon. A superamplification effect was observed when the ATE nanoaggregates were used as fluorescent chemosensor for explosive detection: the quenching efficiency was greatly increased in a nonlinear fashion with increasing quencher concentration.