Macromolecules, Vol.47, No.11, 3736-3746, 2014
Dual-Emissive Difluoroboron Naphthyl-Phenyl beta-Diketonate Polylactide Materials: Effects of Heavy Atom Placement and Polymer Molecular Weight
Luminescent materials are important for imaging and sensing. Aromatic difluoroboron beta-diketonate complexes (BF(2)bdks) are classic fluorescent molecules that have been explored as photochemical reagents, two-photon dyes, and oxygen sensors. A series of BF(2)bdks with naphthyl and phenyl groups was synthesized, and photophysical properties were investigated in both methylene chloride and poly(lactic acid) (PLA). Polymer molecular weight and dye attachment site along with bromide heavy atom placement were varied to tune optical properties of dye-PLA materials. Systems without heavy atoms have long phosphorescence lifetimes, which is useful for lifetime-based oxygen sensing. Bromine substitution on the naphthyl ring resulted in intense, clearly distinguishable fluorescence and phosphorescence peaks important for ratiometric oxygen sensing and imaging.