Madrid Institute for Advanced Studies in Nanoscience , IMDEA Nanociencia, Calle Faraday 9, Universitaria de Cantoblanco , 28049 Madrid , Spain.
REQUIMTE-LAQV, Department of Chemistry and Biochemistry, Faculty of Sciences , University of Porto , 4169-007 Porto , Portugal.
Anal Chem. 2019 Dec 17;91(24):15853-15859. doi: 10.1021/acs.analchem.9b04291. Epub 2019 Nov 21.
Luminescent metal-organic frameworks (LMOFs) are promising materials for lighting and sensing applications. Herein, exposure of the highly luminescent Zn(bpdc)(bpee) MOF (Hbpdc = 4,4'-biphenyldicarboxylic acid and bpee = 1,2-bipyridylethene) to subppm amine contents turns on a new absorption band unambiguously ascribed to free bpee molecules concomitant with the gradual appearance of a new photoluminescence band at shorter wavelengths. These findings combined with Fourier-transform infrared spectra, powder X-ray diffraction and thermogravimetric analysis of exposed LMOF powders confirm that bpee ligands are exchanged by amines and released inside the LMOF, triggering absorption and luminescence features which can be exploited for highly sensitive amine recognition. This principle was demonstrated in mixed matrix membranes (MMMs) prepared by a simple solvent-free method consisting of mixing Zn(bpdc)(bpee) with dimethylvinyl-terminated dimethylsiloxane and dimethylhydrogen siloxane. This method enabled the production of free-standing, permeable, and highly transparent MMMs which showed enormous potential and sensitivity to the detection of amines in gas phase and aqueous medium.
发光金属-有机骨架（LMOFs）是用于照明和传感应用的有前途的材料。在此，将高发光 Zn(bpdc)(bpee) MOF（Hbpdc = 4,4'-联苯二甲酸和 bpee = 1,2-联吡啶乙烯）暴露于亚ppm 级胺含量下，会明确地打开一个新的吸收带，该吸收带归因于游离的 bpee 分子，同时在较短波长处出现新的光致发光带。这些发现与暴露的 LMOF 粉末的傅里叶变换红外光谱、粉末 X 射线衍射和热重分析结合，证实 bpee 配体被胺取代并释放到 LMOF 内部，引发吸收和发光特性，可用于高灵敏度的胺识别。该原理在通过简单的无溶剂方法制备的混合基质膜（MMMs）中得到了证明，该方法由将 Zn(bpdc)(bpee)与二甲基乙烯基封端的二甲基硅氧烷和二甲基氢硅氧烷混合而成。该方法能够生产出具有自支撑性、渗透性和高透明度的 MMMs，这些 MMMs在气相和水相中的胺检测方面显示出巨大的潜力和灵敏度。
