Solvent Induced Luminescence Of Metal Organic Framework Materials And Its Application Research

With the continuous exploration and research of heavy water（deuterium oxide,D₂O）,it continues to shine in cutting-edge scientific fields,such as the need for extremely pure heavy water as a retarder in the field of atomic energy;High concentrations of heavy water are toxic to organisms,while using ordinary water containing a small amount of heavy water can stimulate plant growth,making it highly scientific to detect the concentration of heavy water in water.Due to the similarity in chemical and physical properties between heavy water and ordinary water,as well as their strong water absorption,detecting the concentration of heavy water poses a strong challenge.The current detection methods for heavy water are relatively single,such as specific gravity method,mass spectrometry,etc.,with complex operations and long detection cycles.The research on the quantitative detection of heavy water and water mainly focuses on the direction of trace water,while there is less research on trace heavy water.Metal organic framework materials（MOFs）,as a new type of three-dimensional porous material,have long been active in various fields of scientific research due to their strong adjustable functionality.In our research,we found that through in-depth exploration of metal organic framework materials and the study of solvent induced luminescence phenomena of specific metal organic framework materials,we have discovered their enormous potential in heavy water detection.Rare earth luminescent materials have extremely diverse and complex optical properties based on the f-f transitions and diverse electronic energy levels of lanthanide ions.Therefore,they have long been active in the field of luminescence and have attracted the attention of researchers.Due to their sharp emission bands and long fluorescence lifetime,rare earth luminescent materials have played an extremely important role in the development history of fluorescent probe materials.However,due to the forbidden f-f transition of rare earth light-emitting ions,their own molar extinction coefficient is very low,resulting in low luminous quantum yield,which brings great difficulties to the design of highly sensitive fluorescent probes.The emergence of lanthanide-based metal organic framework materials provides a direction for the further development of fluorescent probes.This article selected amino modified NH₂-MIL-53（Fe）material and lanthanide metal organic skeleton materials（Ln-MOFs）to design and prepare fluorescent probes for detecting heavy water concentration in water.The specific content of this article is as follows:（1）The metal organic skeleton material selected in this chapter is NH₂-MIL-53（Fe）material modified with amino groups,with the introduced ligand being2-aminoterephthalic acid and the metal coordination ion being Fe³⁺ions.A highly sensitive,full range fluorescent probe for heavy water detection can be designed to detect trace amounts of heavy water through the solvent induced luminescence phenomenon discovered in practical operations.The required amino modified NH₂-MIL-53（Fe）metal organic skeleton material was prepared using a one-step hot solvent method,and XRD testing showed that the synthesized material was consistent with the NH₂-MIL-53（Fe）metal organic skeleton material synthesized in previous literature.By comparing the fluorescence spectra of different concentrations of sample solutions prepared at room temperature with an excitation wavelength of361nm,the optimal luminescence concentration was designed,and subsequent experiments were conducted using the optimal luminescence concentration.By comparing the fluorescence spectra of different sample solutions with different p H values at optimal luminescence concentration at room temperature and excitation wavelength of 361 nm,the acid-base dependence and stability of the sample were determined.By analyzing the fluorescence spectra of NH₂-MIL-53（Fe）metal organic skeleton material dispersed in aqueous solutions containing different proportions of heavy water at room temperature with an excitation wavelength of 361 nm,the sample of NH₂-MIL-53（Fe）metal organic skeleton material exhibits fluorescence quenching in heavy water and fluorescence enhancement in pure water,The maximum fluorescence intensity of the characteristic emission peak under specific excitation conditions of the sample was found to be linearly correlated with the content of heavy water in the heavy water solution,reflecting the enormous potential of NH₂-MIL-53（Fe）metal organic skeleton material as a fluorescence probe in heavy water detection.（2）In the article,three rare earth ions Eu³⁺,Ce³⁺,and Gd³⁺were selected as metal ions,sodium acetate was introduced as the"auxiliary group"providing carboxyl groups,and benzoic acid was introduced as an organic ligand.Ce was prepared using a one-step hot solvent method Ce/Eu@Gd-MOFs Metal organic skeleton materials.The prepared lanthanide metal organic skeleton material showed good crystallinity through XRD testing,and the diffraction peak position was consistent with previous published literature.It was also found that the change in the proportion of lanthanide ions did not affect the position of XRD diffraction peaks.By measuring with a fluorescence photometer,different proportions of lanthanide based metal organic skeleton materials are measured under the same conditions to determine the optimal doping ratio.Prepare different concentrations of sample solutions with the optimal doping ratio,and determine the optimal luminescence concentration through fluorescence spectrophotometer measurement.Subsequent experiments will use the optimal doping ratio and luminescence concentration for the samples.By comparing the fluorescence spectra of different sample solutions with different p H values at optimal luminescence concentration at room temperature and excitation wavelength of 260 nm,the acid-base dependence and stability of the sample were determined.By analyzing Ce@Gd-MOFs,Eu@Gd-MOFs,and Ce/Eu@Gd-MOFs,the energy transfer strategy of lanthanide metal ions in the fluorescence spectrum with excitation light of 261 nm was analyzed and applied for detecting heavy water.