源起于发霉甜苜蓿，脱胎于生化实验室，华法林先生起初作为一种强力灭鼠毒药大杀四方。然而，在进入医药领域的道路上，他却因毒药的身份标签和种种流言而饱受质疑和反对。科学家们揭示了华法林抗凝血的机制，并证明了华法林抗凝治疗对患者的益处。从此，华法林先生以及他的衍生物们成为了抗凝治疗和防治鼠害的前线战士。

笔者在大学入学之初就受教于华彤文老师，后来跟随华老师做研究、搞教学、写教材，直至担任《大学化学》主编时依然听取华老师的教诲。在此文中分享40余年来近距离观察、感受和学习华老师严谨治学、勇于担当的教学与研究的态度和方法，期待我国的化学教育教学事业薪火相传，持续发展。

Based on the 5-(3, 4-dicarboxyphenoxy) isophthalic acid (H₄dppa) ligand, two lanthanide metal-organic frameworks (Ln-MOFs) were designed and synthesized by hydrothermal synthesis: {(dima)[Dy(dppa)(H₂O)₂]·2.5H₂O}_n (Dy - MOF) and {(dima) [Eu(dppa) (H₂O)₂]·1.5H₂O}_n (Eu - MOF) (dima=dimethylamine cation). The structures were characterized by elemental analysis, infrared spectroscopy, single-crystal X-ray diffraction, etc. Dy-MOF and Eu- MOF are hetero-isomorphic 2D network structures, and adjacent 2D networks further form 3D supramolecular network structures through hydrogen bonding. Fluorescence analysis shows that Dy-MOF and Eu-MOF have excellent fluorescence properties at room temperature, and Dy-MOF has excellent fluorescence sensing properties, which can efficiently and high-sensitively detect a variety of pollutants in water: aniline (ANI), nitrobenzene (NB), tetracycline (TC), pyrimethanil (PTH), and tryptophan (Trp). The fluorescence quenching mechanism of Dy-MOF in detecting pollutants was also investigated.

We used the natural product chamomile as a carbon source to synthesize praseodymium(Pr) and nitrogen (N) co-doped biomass carbon dots (Pr/N-BCDs) with remarkable luminescence properties by one-step hydrothermal method. Compared with single N doped BCDs (N BCDs) and Prdoped BCDs (PrBCDs), Pr/N BCDs not only showed better fluorescence properties and stability but also achieved a significant increase in quantum yield of 12%. More importantly, under certain conditions, Pr/N-BCDs and 2, 4-dinitrophenylhydrazide (2, 4-DNPH) had significant fluorescence internal filtration effect (IFE) and dynamic quenching effect, and in the concentration range of 0.50-20 μmol·L^-1, the concentration of 2, 4-DNPH had a good linear relationship with the fluorescence quenching signal, and the detection limit was as low as 2.1 nmol·L^-1.

A coordination polymer {[Cd(H₂dpa)(bpy)]·3H₂O}_n (Cd-CP) was designed and hydrothermal synthesized based on 4-(2, 4-dicarboxyphenoxy) phthalic acid (H₄dpa), 2, 2′-bipyridine (bpy) and Cd(NO₃)₂·4H₂O. The structure was characterized by single-crystal X-ray diffraction, powder X-ray diffraction, elemental analysis, and infrared spectroscopy. Cd-CP belongs to the monoclinic crystal system with the P2₁/c space group and performs in a 1D double-chain structure. The adjacent double chains further form a 3D supramolecular network structure through hydrogen bonding. Thermogravimetric analysis shows that Cd-CP has good thermal stability. Fluorescence analysis showed that Cd-CP had good choosing selectively and was sensitive to metal ions (Fe³⁺ and Zn²⁺), 2, 4, 6-trinitrophenylhydrazine (TRI), and pyrimethanil (Pth). Interestingly, when Cd-CP was used for fluorescence detection of metal ions, it was found to have a fluorescence quenching effect on Fe³⁺ but had an obvious enhancement effect on Zn²⁺. Therefore, we designed an "on-off-on" logic gate. In addition, the mechanism of fluorescence sensing has been deeply explored.

A cadmium-based coordination polymer [Cd₄(L)₄(1,4-bib)₄]·2DMA (CP1) was synthesized under solvothermal conditions, where H₂L=2 hydroxyterephthalic acid, 1, 4 bib=1, 4 bis(imidazol1 ylmethyl) benzene, and DMA=N,N-dimethylacetamide. The structure was characterized by thermogravimetric analysis, elemental analysis, infrared spectroscopy, and single-crystal X-ray diffraction. The single crystal structure shows that CP1 belongs to the orthorhombic system, the space group Pna2₁, Cd(Ⅱ) forms a 2D plane structure through L^2-, and the 2D plane structure forms a 3D network with pcu topology through 1,4-bib. CP1 shows good fluorescence sensing performance and thermal stability and realizes efficient and sensitive detection of 2,4,6-trinitrophenol (TNP), Fe³⁺, and fluridine (FLU). The detection limits were 0.051 μmol·L^-1 (TNP), 0.65 μmol·L^-1 (Fe³⁺), and 0.14 μmol·L^-1 (FLU), respectively. In addition, the mechanism of fluorescence detection of pollutant detection was explored and a portable test paper was successfully prepared. A portable test paper could not only selectively detect FLU, but also showed different fluorescence colors in different concentrations of FLU.

In this study, using 3, 5-di(3′, 5′-dicarboxylphenyl)-1H-1, 2, 4-triazole (H₄L) as ligands, a gadolinia-based organic framework complex {[GdNa(L)(H₂O)₃]·2H₂O}_n (Gd-Na-MOF) was successfully designed and synthesized by hydrothermal method. The structure and properties were systematically characterized and tested by techniques such as single-crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, infrared spectroscopy, and fluorescence spectroscopy. The results indicate that this complex has a unique 3D structure, excellent thermal stability, and outstanding luminescent performance. Based on its luminescent properties, a polymer-embedding method was employed to fabricate the Gd-Na-MOF into a flexible, washable composite fluorescent film, Gd-Na-MOF@PMMA/BMA (PMMA=polymethyl methacrylate, BMA=butyl methacrylate). This fluorescent film exhibited highly sensitive recognition capability for tyramine, with a low detection limit of 1.66 μmol·L^-1. It was used for the detection of tyramine in bananas, with a recovery rate of 96.92%-100.26%.

Based on 4′-(1H-tetrazol-5-yl)-[1, 1′-biphenyl]-2, 4, 6-tricarboxylic acid (H₄bta) ligand, zinc metal-organic framework (Zn-MOF): {[Zn₂(bta)(bpy)₂(H₂O)]·1.5H₂O}_n (bpy=2, 2′-bipyridine) was designed and synthesized by hydrothermal method. Its structure was characterized by elemental analysis, IR spectra, X-ray single crystal diffraction, etc. The asymmetric unit of Zn-MOF contains two crystallographically independent Zn²⁺ ions. Through the connection of Zn²⁺ ions via H₄bta, a 1D double-layer network structure is formed. Adjacent double-layer networks further form a 2D supramolecular network through hydrogen bonding. Notably, Zn-MOF exhibited excellent fluorescence properties and could efficiently and sensitively detect various water pollutants: 4-nitrophenol (4-NP), Cu²⁺, and pyrimethanil (Pth). Additionally, the mechanism of fluorescence sensing was investigated.

To address the challenges of poor solubility and difficult recyclability of powdered metal-organic frameworks (MOFs), a Eu-based MOF complex, [EuNa(L)(H₂O)₃]·2H₂O (Eu/Na-MOF), was synthesized by the hydrothermal method using 3,5-bis(3,5-dicarboxyphenyl)-1H-1,2,4-triazole (H₄L) as the ligand in this study. Systematic characterization and performance evaluation revealed that the complex exhibits a unique 3D structure, high phase purity, excellent thermal stability, and outstanding luminescent properties. Furthermore, the complex was encapsulated in poly(methyl methacrylate) (PMMA) to fabricate a flexible and water-washable composite fluorescent film (Eu/Na-MOF/PMMA). Based on static and dynamic quenching mechanisms, respectively, the film enables reversible detection of tryptamine and Cr₂O₇^2- ions in aqueous solutions, demonstrating high selectivity, stability, and portability.