Fabrication Of Functionalized Dendritic Organogels From Poly(benzyl Ether) Dendrons And Their Applications

Dendrimers and dendrons are highly branched macromolecules with well-defined molecular architecture and have been widely used as building blocks in the self-assembling of supramolecular gel-phase materials. To date, a number of physically thermoreversible organogels based on dendritic macromolecules have been reported. However, there have been very limited examples of dendritic organogels with multiple functionalities. In this dissertation, great efforts have been focused on the development of new functionalized dendritic organogels and the study on their self-assembly behaviors and potential applications.(1) A new highly efficient and versatile poly(benzyl ether) dendritic organogelator HPB-G1 with HPB at the focal point was designed and synthesized. It was found that HPB-G1 could form stable organogels toward various apolar and polar organic solvents. Further studies revealed that the intermolecular multiple π-π stacking interactions were the main driving forces for the formation of organogels. Notably, the dendron HPB-G1 exhibited a significantly enhanced emission in the gel state, in contrast to weak emission in solution. Most interestingly, these dendritic organogels exhibited multiple stimuli-responsive behaviors upon exposure to environmental stimuli including temperature, anion, metal cation, acid/base, sonication, and shear stress, leading to reversible gel-sol phase transitions.、(2) A new class of poly(benzyl ether) dendritic ligands with chiral oxazoline functionality at the focal point and their corresponding Cu(Ⅱ) complexes were designed and synthesized. Compared to the dendritic ligands, the corresponding dendritic complexes exhibited much better gelation ability in various organic solvents. The morphology could be finely tuned by the coordination of Cu(Ⅱ) to the ligand. Interestingly, these metallogels could intelligently respond to multiple external stimuli including temperature, chemicals, redox and sonication, leading to gel-sol phase transitions. In addition, the supramolecular chirality of these dendritic metallogels and their application in chiral recognition has been studied.