Design of large π-conjugated α-cyanostilbene derivatives as colorimetric sensors for volatile acids and organic amine gases
Design of large π-conjugated α-cyanostilbene derivatives as colorimetric sensors for volatile acids and organic amine gases
复制标题
大型α-共轭α-氰芪衍生物作为挥发酸和有机胺气体比色传感器的设计
DOI：
10.1039/c9tc06148g
复制
发表时间：
2020-03-28
影响因子：
6.4
通讯作者：
Hou, Ji-ting
中科院分区：
文献类型：
--
作者：
Cao, Xinhua;Li, Yiran;Hou, Ji-ting
以间苯二乙腈、对苯二乙腈和4-二甲氨基肉桂醛为原料，通过Knovenagel缩合反应，设计并合成了两个大的(2Z，2‘Z，4E，4’E)-2，2-‘-(1，3-phenylene)bis(5-(4-(dimethylamino)phenyl)penta-2，4-dienenitrile)(M-’-(1，4-phenylene)bis(5-(4-(dimethylamino)-phenyl)penta-2，4-dienenitrile))和(2Z，2‘Z，4E，4’E)-2，2-PDC(P-PDC)。这两个α-氰基二苯乙烯衍生物都是异构体，它们的吸收、发射、量子产率和寿命等光学性质都可以通过异构体效应来调节。在相同条件下，P-PDC比M-PDC在波长上都有一个吸收带和发射峰。与M-PDC相比，P-PDC具有更高的荧光量子产率。基于密度泛函理论(DFT)的理论计算表明，P-PDC比M-PDC具有更大的pi共轭体系。以两个二甲胺单元为质子结合部位的M-PDC和P-PDC对某些具有一定酸性的挥发酸具有灵敏的肉眼检测能力。例如，M-PDC和P-PDC在CH2Cl2中溶液的检出限分别为2.0和8.82 nm。M-PDC和P-PDC在添加TFA的CH2Cl2溶液中可检出部分有机胺，对茶叶的检出限分别为1.76和3.47 nm。M-PDC和P-PDC在CH2Cl2中的溶液被涂覆在石英板上，形成了不同形貌的薄膜，由于ACQ效应，薄膜发出了非常微弱的光。但是，幸运的是，通过引入CTAB可以克服M-PDC和P-PDC薄膜中的ACQ效应，它们的荧光分别增强了225倍和105倍。这些结果使得对挥发性酸性气体的反应成为可能。M-PDC和P-PDC薄膜对TFA的检出限分别为17.4和2.37ppm。M-PDC和P-PDC薄膜依次与挥发酸和有机胺气体接触，表现出良好的可逆性。本研究将为构建气态酸和有机胺的功能性大分子共轭体系提供一条新的途径。
Two large pi-conjugated alpha-cyanostilbene derivatives (2Z,2 ' Z,4E,4 ' E)-2,2 '-(1,3-phenylene)bis(5-(4-(dimethylamino)phenyl)penta-2,4-dienenitrile) (M-PDC) and (2Z,2 ' Z,4E,4 ' E)-2,2 '-(1,4-phenylene)bis(5-(4-(dimethylamino)-phenyl)penta-2,4-dienenitrile) (P-PDC) were designed and synthesized through a Knoevenagel condensation reaction between m-phenylenediacetonitrile, p-phenylenediacetonitrile and 4-(dimethylamino)cinnamaldehyde. The two alpha-cyanostilbene derivatives were isomers, and their optical properties including absorption, emission, quantum yields and lifetime could be tuned by the isomer effect. P-PDC showed an absorption band and an emission peak all at larger wavelengths than M-PDC under the same conditions. Compared to M-PDC, P-PDC exhibited a higher fluorescence quantum yield. Theoretical calculations demonstrated that P-PDC possessed a larger pi-conjugated system than M-PDC based on the density functional theory (DFT) method. M-PDC and P-PDC with two dimethyl amine units as proton binding sites showed sensitive naked eye detection ability toward some volatile acids with certain acidity. For example, the limits of detection of solutions of M-PDC and P-PDC in CH2Cl2 were 2.0 and 8.82 nM. Solutions of M-PDC and P-PDC in CH2Cl2 with the addition of TFA could detect some organic amines, and the limits of detection towards TEA were 1.76 and 3.47 nM. Solutions of M-PDC and P-PDC in CH2Cl2 were coated onto a quartz plate and formed a film with different morphologies, which emitted very weak light due to the ACQ effect. But, fortunately, the ACQ effect in the M-PDC and P-PDC films could be overcome via the introduction of CTAB and they exhibited great fluorescence enhancement by 225-fold and 105-fold, respectively. These results enabled a response towards volatile acid gases. The limit of detection of the M-PDC and P-PDC films towards TFA was 17.4 and 2.37 ppm. The M-PDC and P-PDC films showed good reversibility by contacting with volatile acids and organic amine gases in turn. This research will provide a new route for the construction of functional large pi-conjugated systems for the detection of gaseous acids and organic amines.