固体三芳基硼-相变材料可调比率荧光温度计

Solid Tunable Ratiometric Fluorescence Thermometers Based on Triarylboron-Phase Change Materials

温度响应相变材料(PCMs)的微区黏度和自由体积等性质在熔点附近会发生可逆且快速的变化,这种变化可以放大荧光探针的响应性.本文合成了2个对高黏度具有比率响应发光的新型三芳基硼化合物4-(1-{4-[双(4-溴-2,3,5,6-四甲基苯基)硼烷基]-2,3,5,6-四甲基苯基}哌啶-4-基)吗啉(MPDB1)和4,4-({[(4-溴-2,3,5,6-四甲基苯基)硼烷二基]双(2,3,5,6-四甲基-4,1-亚苯基)}双(哌啶-1,4-二基))二吗啉(MPDB2),并将其与相变材料结合,制备了高灵敏度比率荧光温度计.由于化合物的高黏度响应性质,其在相变材料中的温度荧光响应范围低于体系熔点,因此得到在量程范围内为纯固体的相变材料荧光温度计,具有良好的加工性.作为黏度探针,一取代的MPDB1的荧光响应范围为100~3000 mPa·s,灵敏度高;而二取代的MPDB2则在100~46000 mPa·s的黏度区域有荧光响应,覆盖范围广.作为温度探针,MPDB1-聚乙二醇20000(PEG20000)体系的荧光温度响应区间为-10~50℃,最大相对灵敏度(Sr)为3.5%(10℃),绝对灵敏度(Sa)为4.6%(30℃),灵敏度较高,且其温度测量范围可以通过取代基数目和选用不同熔点的聚乙二醇介质调整,具有较强的适用性.

Microregion viscosity and free volume of phase change materials(PCMs)undergo reversible and rapid changes near the melting point,which can amplify the responses of fluorescent probes.In this study,two novel triarylborons,4-(1-{4-[bis(4-bromo-2,3,5,6-tetramethylphenyl)boraneyl]-2,3,5,6-tetramethylphenyl}piperidin-4-yl)morpholine(MPDB1)and 4,4'-({[(4-bromo-2,3,5,6-tetramethylphenyl)boranediyl]bis(2,3,5,6-tetramethyl-4,1-phenylene)}bis(piperidine-1,4-diyl))dimorpholine(MPDB2),with ratiometric-responsive fluorescence to high viscosity were synthesized and then combined with PCMs,thus high-sensitivity ratiometric fluorescence thermometers were prepared.Due to the compounds’rare high viscosity responsiveness,the temperature fluorescence response ranges in the PCMs are lower than their melting point,thus producing pure solid-state PCMs fluorescent thermometers with better processability.As viscosity probes,the fluorescence of the mono-substituted compound MPDB1 shows a ratiometric response range of 100—3000 mPa·s with high sensitivity,while the fluorescence of the compound MPDB2 responds from 100 to 46000 mPa·s,covering a wider range.As temperature probes,the fluorescence temperature response range of the MPDB1-polyethylene glycol 20000(PEG20000)system is -10—50℃,with a high maximum relative sensitivity of 3.5%(Sr,10℃)and absolute sensitivity of 4.6%(Sa,30℃).Also,the temperature measurement range of these thermometers can be adjusted by changing the number of substituents and selecting PEG substrates with different melting points,rendering better applicability.