The Preparation And Properties Of Metal-organic Gels Based On Benzimidazole Derivatives

This paper includes four chapters:Chapter One: This one is about the development history and research ofsupramolecular gels in recent years. Including three parts:(Ⅰ) supramolecularorganic gels;(Ⅱ) supramolecular metal-organic gels. Because of thestimuli-responsive (including temperature, solvent composition, light, electric, etc.)ofsupramolecular gels, they could be applied many fields， such as molecular sensingdrug carriers, and food, ect.Chapter Two: Three multi-responsiveness supramolecular metal-organic gels(MOGs) have been prepared upon Ba(Ac)2, CdSO4·8H2O and Pb(NO3)2with a simpleligand (G17) based on a carboxyl-functionalized benzimidazole derivative inalcoholic-water solutions. The MOGs display the formation of well-developednanofibrillar networks composed of intertwined fibers which provide stability to gelsstructures through coordination, hydrogen bonding and π–π interactions werecharacterized using field emission scanning electron microscopy (FESEM), thefourier transform infrared (FT-IR) spectroscopy and powder X-ray diffraction (XRD)techniques. MOG-1shows good stimuli responsiveness toward the changes in K2CrO4,both MOG-2and MOG-3do good job toward the changes in Na2S. Moreover, due tothese MOGs were formed easily by gelator and some heavy metal ion, such as Cd(Ⅱ)and Pb(Ⅱ), it might provide the basis for heavy metal ion pollution capture andremoval.Chapter Three: A multi-responsiveness supramolecular metal-organic gel (MOG)has been prepared by silver (I) nitrate and a simple ligand (L17) based on abiscarboxyl-functionalized benzimidazole derivative. The MOG which displays theformation of well-developed nanofibrillar networks composed of intertwined fiberswas characterized using field emission scanning electron microscopy (FESEM),Fourier transform infrared (FT-IR) spectroscopy and powder X-ray diffraction (XRD)techniques. The FT-IR spectra and XRD show that supramolecular MOG was formedthrough an effective coordination of the ligand and Ag+. This MOG revealsoutstanding reversible sol–gel transitions induced by changes of temperature and pH, as well as addition of NH4OH, EDTA, and Na2S. In addition, the MOG also shows atendency in effective dye removal agent. These results demonstrate this multi-channelresponsive smart MOG has the potential to be widely applied in materials science.Chapter Four: Select the MOG of Chapter Three as adsorbent. The adsorptionability of the MOG for rhodamine B, methyl orange and malachite green was studied,the results showed that, in aqueous phases, the MOG can adsorb methyl orangemolecules selectively. More study indicated that, when the dosage was5mg,adsorption time was40~60min, the ratio of gelator and metal ions was1：1, pH valuewas5~11, the adsorption performance reached optimum one. Absorption behavior ofthe MOG for methyl orange conforms to liquid film diffusion model. Isothermadsorption process can be well described by Langmuir and Freundlich models.