화학공학소재연구정보센터
Macromolecules, Vol.52, No.19, 7477-7488, 2019
Highly Fluorescent Benzophosphole Oxide Block-Copolymer Micelles
The efficient synthesis of highly fluorescent para-biphenylsubstituted benzophospholes via zirconium-mediated metallacycle transfer is reported. A norbornene-appended benzophosphole oxide monomer was found to readily undergo living ring-opening metathesis polymerization with the Grubbs third-generation catalyst to yield either a homopolymer or block copolymers. The resulting block copolymers consisting of lipophilic alkylatedor pinacolboronate-capped comonomers undergo self-assembly into spherical micelles in tetrahydrofuran/hexanes mixtures, as determined by dynamic light scattering and transmission electron microscopy. One hallmark of the benzophosphole-containing polymers is their greatly enhanced emission intensity in solution in relation to their monomers, presumably due to a restriction in molecular motion upon formation of homopolymers or assembled block-copolymer micelles. Evidence for "analyte amplified precipitation" was found, wherein addition of a substoichiometric amount of fluoride to a benzophosphole oxide-pinacolboronate block-copolymer spherical micelle leads to rapid precipitation of highly emissive aggregates. This observation should guide the development of related methods to visually detect (and sequester) analytes in solution.