近红外荧光探针对黏度和极性的双响应

Dual responses of near infrared fluorescence probe to viscosity and polarity

以3,4-二甲氧基吡喃酮为吸电子基团、半花菁染料为给电子基团,通过Witting反应合成了一种基于真菌荧光素的近红外荧光探针FUNG。通过^(1)HNMR、^(13)CNMR和HRMS表征了其结构,测试其对不同溶液体系的黏度、极性的响应性能,考察其在响应过程中的抗干扰能力、p H适用范围。结果表明,探针FUNG在水中的斯托克斯位移为178 nm,荧光发射波长(λ_(em))为700 nm,能同时对溶液体系的黏度和极性作出响应,符合扭曲的分子内电荷转移机制;在不同体积分数甘油水溶液中,探针FUNG对溶液黏度的响应表现为荧光强度线性变化,随着溶液的黏度的增加,其在700 nm处荧光强度增加6倍多,荧光寿命也能随之增加;探针FUNG对溶液极性的响应表现为荧光发射光谱的红移,随着溶剂极性参数的增加,λ_(em)从606 nm红移至698 nm;在甲苯/二甲基亚砜(DMSO)中,随着甲苯体积分数从100%减至10%,λ_(em)从669 nm红移至712 nm;在1,4-二氧六环/DMSO中,随着1,4-二氧六环体积分数从100%减至10%,λ_(em)从631 nm红移至717 nm;探针FUNG对溶液黏度和极性的响应具有选择性好、抗干扰能力强、pH适用范围广等特点。

A fungal fluorescein-based near-infrared fluorescence probe FUNG was synthesized from Witting reaction between 3,4-dimethoxypyranone as electron-withdrawing group and semicarbocyanine dye as electron-donating group,and characterized by ^(1)HNMR,^(13)CNMR and HRMS.The response performance of the probe to viscosity and polarity of different solution systems was evaluated,while its anti-interference ability and pH applicability during the response process were also investigated.The results showed that the Stokes shift of FUNG in water was 178 nm,and the fluorescence emission wavelength(λ_(em))was 700 nm.The probe could respond to the viscosity and polarity of different solution systems simultaneously,following a complex twisted intramolecular charge transfer(TICT)mechanism.In glycerol/water solutions with different glycerol volume fractions,the fluorescence intensity of the probe showed a linear relationship with solution viscosity,with its fluorescence intensity at 700 nm increased by about six times with the increase of the solution viscosity and its fluorescence lifetime increased accordingly.The response of the probe FUNG to the polarity of the solution was reflected by the red-shift of its fluorescence emission spectra,with its emission wavelength(λ_(em))red-shifted from 606 nm to 698 nm with the increase of solvent polarity parameter.λ_(em) red-shifted from 669 nm to 712 nm with the decrease of the volume fraction of toluene from 100%to 10%in toluene/dimethyl sulfoxide(DMSO)solution,and from 631 nm to 717 nm when the volume fraction of 1,4-dioxane decreased from 100%to 10%in 1,4-dioxane/DMSO solution.The response of probe FUNG to the viscosity and polarity of solution displayed good selectivity,strong anti-interference ability,and a wide pH range.