基于苯炔苯及荧光探针芘自组装单分子膜的制备及苯胺检测

Fabrication of Self-Assembled Monolayer Based on Phenylethynylbenzene and Fluorescent Probe Pyrene and Detecting for Nitroanilines

利用重氮基的光分解活性、采用自组装的方法将带有功能基团NH2的4-(4-氨基苯乙炔基)苯共价键接在石英基片上制备了共轭单分子膜;利用膜上NH2的反应活性,通过酰胺化反应或自组装的方式将稠环芘修饰在单分子膜上,构筑了含有芘荧光探针的稳定发光超薄膜;该薄膜能够与电子受体硝基苯胺间因相互作用形成电荷转移络合物而使其荧光猝灭,并且该薄膜对硝基苯胺同分异构体的荧光猝灭响应有明显的差异,其中对硝基苯胺对功能薄膜的猝灭效应最为明显,其次是邻硝基苯胺和间硝基苯胺;且具有明显的浓度依赖性.

Self-Assembled monolayers（SAMs）,a new type of organic ultra-thin films,show a lot of interesting properties in chemistry,physics,optics and electronic transport,and have potential application in biomaterials,nanoelectro-mechanical systems,sensors,and so on.In this paper,a full-conjugated unit-containing SAM ended with a functional amino group（NH2） was fabricated by self-assembly and using a light-sensitive diazonium-containing compound 4-（4-amino phenylene ethynyl） benzenic diazonium salt（APEB-N2＋）.The APEB-N2＋ was easily deposited on a pre-treated quartz substrate with negative charges by electrostatic interaction and then grafted on the surface of a quartz substrate through covalent bond after the decomposition of diazonium group under UV irradiation,and a stable SAM based on phenylethynylbenzene was obtained.Furthermore,based on the reactivity of the functional group NH2,the fluorescent probe pyrene is anchored on the surface of the full-conjugated SAM through two approaches： amidation reaction between amino group on the SAM and carboxyl group of 1-pyrenebutyric acid,and self-assembly of N2＋,which is transferred from NH2 on SAM,and electronegative COO-of 1-pyrenebutyric acid in basic aqueous solution.The obtained ultra-thin films with fluorescence probe pyrene exhibit luminescent property because of the emission of excimer of pyrene chromophore,which is mainly due to the formation of the g-g conformation of pyrene for the induction effect of the full-conjugated SAM.The electron-acceptor nitroanilines（NAs） can quench the fluorescence of the obtained ultra-thin film because of electron and energy transfer between the electron-rich pyrene and NAs.The fluorescence quenching varies obviously for the different isomers of NA,and the quenching efficiency decreases according to the sequence of p-NA,o-NA,m-NA,because the electronic effect varies obviously when the relative position of electron withdrawing group NO2 and donating group NH2 of NA are different.The fluorescence of the ultra-thin film decreases with the increasing of the NA concentration.