Preparation And Property Study Of Nanoscale Complexes/Polymers Based On Schiff Base Ligands

Nanomaterials have gained more and more attentions because of their special optical, electric, magnetic, mechanical, and chemical properties. Recently, preparation of nanostructured materials through molecular self-assembly became a hot spot. The key of this thesis is controlling morphology and properties of coordination complex/polymer nanoparticles and study the ligand-structure effect. The main works of this thesis were summarized as follows:1. We have synthesized seven Schiff base ligands H2L1, HL2, H2L3, H2L4, H2L5, H3L6and H3L7and fully characterized them by Nuclear Magnetic Resonance (NMR), Mass Spectrometry (MS), Infrared Spectroscopy (IR) and Elemental analysis.2. Metallogels of L1-Cu was prepared in DMF. L1-Cu acts as a "super-gelators" with critical concentration of0.31wt%for DMF. The effect of solvent, ultrasound and ultrasound time on nanoparticles morphology was also investigated in detail. Nanofibers were obtained in DMF, ethanol, ethyl acetate, toluene, and water. However, nanobelts were found in THF. And nanorods can be formed under ultrasonication in DMF or THF. Longer time of ultrasonication leads to shorter nanorods. The formation of1D nanostructure indicates that the intermolecular forces between complexes L1-Cu are strong enough to overcome the rapid aggregation under different synthetic conditions. The mechanism of forming1D nanostructure was studied.3. The ligand H2L1exhibits good selectivity toward different metal ions in term of metallogels formation. After addition of different metal acetate salts (Cu2+, Zn2+, Cd2+, Co2+, Mn2+, Ni2+, Li+), only L1-Cu forms gels. Besides, the ligand also exhibits good selectivity toward solvents in term of metallogels formation. Metallogels are only formed in DMF and DMSO.4. Organic ligand H3L6can self-assemble into nanofibers. At the same time, nanoscale or submicroscale coordination polymers of L5-Zn, L6-Zn and L7-Zn with uniform sizes were prepared. Modification of the ligands modified by long alkyl chain can effectively stabilize the nanoparticles and reduce particle sizes.