DeRosa Christopher A, Kolpaczynska Milena, Kerr Caroline, Daly Margaret L, Morris William A, Fraser Cassandra L
Department of Chemistry, University of Virginia, McCormick Road, Charlottesville, VA, 22904, USA.
Chempluschem. 2017 Mar;82(3):399-406. doi: 10.1002/cplu.201600520. Epub 2016 Dec 8.
Difluoroboron β-diketonate-polylactides are versatile oxygen-sensing materials. These materials have both fluorescence (F) and oxygen-sensitive, room-temperature phosphorescence (RTP). The fluorescence, being insensitive to oxygen, can act as an internal standard to the changing phosphorescence, and ratiometric sensing of oxygen can be achieved with these simple, single-component materials. To expand the range of colors for this family of fluorophores, a series of thienyl-phenyl-substituted dyes were synthesized with initiator sites for the ring-opening polymerization of lactide. Heavy atoms (Br and I) were added to the dye to modulate the phosphorescence intensity. These halide-substituted thiophene dyes readily aggregated in the poly(lactic acid) (PLA) matrix, generating two fluorescence peaks in air, one for monomer emission and another for aggregate emission. When the dye was dilute in PLA, as a blend, the iodo-thienyl derivative showed impressive singlet-triplet splitting, with blue fluorescence (440 nm) and orange phosphorescence (585 nm), the largest gap recorded for a boron β-diketonate dye. Nanoparticles fabricated from a mixture of PLA and dye-PLA conjugated polymer benefited from the large singlet-triplet splitting to yield oxygen sensitivity at levels between 0 and 21 %, which can be utilized in biological oxygen-sensing applications.
二氟硼β-二酮酸酯-聚丙交酯是多功能的氧传感材料。这些材料兼具荧光（F）和对氧敏感的室温磷光（RTP）。对氧不敏感的荧光可作为变化磷光的内标，利用这些简单的单组分材料即可实现氧的比率传感。为了扩大该荧光团家族的颜色范围，合成了一系列带有丙交酯开环聚合引发位点的噻吩基-苯基取代染料。向染料中添加重原子（Br和I）以调节磷光强度。这些卤代取代的噻吩染料在聚乳酸（PLA）基质中容易聚集，在空气中产生两个荧光峰，一个用于单体发射，另一个用于聚集体发射。当染料在PLA中作为共混物稀释时，碘代噻吩基衍生物表现出令人印象深刻的单重态-三重态分裂，具有蓝色荧光（440 nm）和橙色磷光（585 nm），这是硼β-二酮酸酯染料记录到的最大能隙。由PLA与染料-PLA共轭聚合物的混合物制成的纳米颗粒受益于大的单重态-三重态分裂，在0%至21%的水平上产生氧敏感性，可用于生物氧传感应用。
