Study On Benzimidazolium Salt Metal Complexes And Supramolecular Metal Gels

Benzimidazolium salt is the derivatives of imidazole salt. In addition to the fineproperties of the imidazole salt, it has a variety of new features owing to theintermolecular π-π interaction caused by the presence of benzene ring and has somepotential applications in catalysis, electrochemistry, fluorescent probes, analyticalchemistry, materials and biological activity. In addition, supramolecular gels haveevolved into a class of smart/functional nanomaterials with extensive applicationpotentials recently. Most supramolecular gels studied today employ hydrogen bondingor molecular stacking as the driving force for gelation. Despite the major role thatmetal coordination plays in supramolecular chemistry, the use of metal-ligandinteractions in the area of supramolecular gels has been somewhat neglected untilvery recently. Supramolecular gels including metal ions can capitalize on the uniquerichness of the attributes of metal ions such as photo-electronic, catalytic, redox,which stimulates research in this area. In view of this, we synthesized novelbenzimidazolium salt metal complexes and further synthesized supramolecular metalgels containing Cd（II）, Cu（II）, Zn（II）. From the study we found it can stimulativeresponse to the pH changing.The relative content is as follows:1. Research on the development of benzimidazole onium salt of metal complexes andgels.2. O-phenylenediamine and chloroacetic acid as substrate were synthesized by analkylation pairs of carboxylic acid functional Benzimidazole Salts. and then metalcomplexes [Ni（dpa）₂（H₂O）₄]（1）,[Cu（Hdpa）₂（H₂O）₂]（2）（Hdpa=2,2-（2-methyl-benzimidazolium-1,3-diyl） diacetate） have been synthesized with metalnickel and copper and characterized by IR, UV spectra and elemental analysis, Thesingle crystal structures of the title compounds were determined by X-ray diffraction.In crystal, the title compounds self-assembled to three-dimensional porous structureby π-π interaction, hydrogen bonding and intercalation of groups. Moreover,according to the stabilities of the hydrogen bonds and the intermolecular π-πinteraction, we could predict that the comp ound1is more stable than2, which is in good agreement with the available exp eriments thermal stabilities.3. A series of supramolecular metal hydrogels have been synthesized by ultrasound ofbenzimidazole onium salt-based Cd（II）, Cu（II）, Zn（II） complexes. From the study wefound that the formation of the metal and the ligand complexes is the key to prepare agel. The resulting gels display a good stimuli-responsive to EDTA and acid/base,which can be applied in molecular switches.