Research On Preparation And Property Of Metallogels And Complexes Based On Schiff Base With Long Alkyl Chain

In this paper, three new Schiff base ligands H2L1, H2L2and H2L3were successfully designed and synthesized and complexes were formed by self-assembly through the coordination bond between multidentate organic ligands and central metal ion, which were characterized by mass spectrometry, elemental analysis, nuclear magnetic resonance, UV-visible absorption spectrum and infrared spectroscopy. Length of alkyl chain, anions, ultrasound time, solvents have effects on the formation of gels. Mechanism of formation metallogels was further studied in detail.Metallogels of L2-Cu and L3-Cu were prepared in dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF) solvents, the critical concentration of gel L2-Cu and L3-Cu in DMF is0.25wt%,0.19wt%, respectively, which indicates L2-Cu and L3-Cu are supergelators. The morphology of L2-Cu was from nanofibres to nanorods with the increase of ultrasound time; ultrasound induces the shift of L2-Cu from nanofibers to short nanorods. The appropriate increase of the concentration of the reactants helps to form gel; longer length alkyl chain conduces to induce formation of a gel; polar solvents as DMF and DMSO with strong ability to form hydrogen bonds can readily form gels; acetate ions can provide weakly alkaline condition and help ligand deprotonation and formation gel with Cu2+coordination; and the gel was formed when the ligand was only coordinated with Cu2+. Thermodynamic stability of the the complexes L-Cu have been investigated by thermal gravimetric analysis. Porous PMMA were synthesized by using gel L2-Cu as a template.The effect of the ultrasonic time, concentration, solvents and alkyl chain length had effects on the morphologies of complexes L2-Zn and L2-Cd was studied. In addition, the optical properties of H2L and L-Cd were also researched by fluorescence spectra.