Three Schiff base ligands containing two pyridine rings, S1, S2, and S3, show strong gelation abilities with AgNO3 in several pure or mixed solvents at room temperature. 1H NMR and Fourier transform infrared spectroscopy measurements not only demonstrated the coordination interaction between silver ion and nitrogen atom of the pyridine ring of the S2 ligand in S2-Ag metallogel, but also showed that hydrogen bonding contributes to the formation of the metallogels. In particular, S2-Ag metallogel shows a super smart and fully reversible thixotropic property, which has been rarely reported before in metallogels. X-ray diffraction (XRD) analysis revealed that S2-Ag metallogel in DMF takes a mixture of hexagonal and tetragonal packing modes. On the basis of the results of XRD and mass spectrometry analysis, a possible structure evolution process for the gel was proposed. And this model was further demonstrated by the results of polarizing microscopy and thermogravimetric analysis of S2-Ag metallogel.
三种含有两个
吡啶环的 Schiff 碱
配体 S1、S2 和 S3 在室温下与 AgNO3 的反应中表现出强烈的胶凝能力,适用于多种纯溶剂或混合溶剂。1H NMR 和傅里叶变换红外光谱测量不仅证明了
银离子与 S2
配体的
吡啶环氮原子之间的配位相互作用,还显示出氢键在
金属胶体形成中的贡献。特别是 S2-Ag
金属胶体展现出超智能且完全可逆的触变特性,这在
金属胶体中很少被报道。X 射线衍射 (XRD) 分析显示 S2-Ag
金属胶体在
DMF 中呈现六角形和四方形混合堆积模式。基于 XRD 和质谱分析的结果,提出了凝胶的可能结构演变过程,并通过 S2-Ag
金属胶体的偏振显微镜和热重分析结果进一步证明了该模型。