Construction, Control And Property Of Self-assembly Systems Via Multiple Hydrogen Bonding

Due to its high directionality, specificity, adjustability, and relatively highstrength, hydrogen bonding has been described as the "masterkey interaction insupramolecular chemistry". Systems capable of forming multiple hydrogen bonds canovercome the defects that single hydrogen bond can’t accomplish and have beenwidely applied in the fields of supramolecular polymers and supramolecularassemblies. Based on two types of specific self-assembly modes mediated byhydrogen bonding, i. e., self-assembly of cyclic hexamers from hydrazide motifslinked by a120°isophthalamide spacer and dimerization of UPy(Ureidopyrimidinone) via quadruply hydrogen bonding, this thesis aims atconstruction, structural analysis, control and property study of self-assembly systemsmediated by multiple hydrogen bonds.In the first part, we just moving the alkoxy substitution on the isophthalamidespacer unit from position5to position4to form intramolecular hydrogen bonding tofix the syn-anti conformation of the spacer, precise control of the two hydrazide unitsin the cyclic hexamers (in or out) was accomplished.In the second part, we applied the strategy for precise location of differentfunctional groups on the cyclic hexamers that we developed in the first part.Functional carbazolyls were introduced into the4-alkoxy derived isophthalamidespacer units of the self-assembly monomers and precise location of the carbazolylswas achieved. Different location led to different emission property of carbazolyls.In the third part, we constructed a type of supramolecular polymer viaindependent and cooperative interactions of different hydrogen bonding motifs byintroducing UPy unit into the isophthalamide spacer unit of the monomer forhydrazide-based self-assembled cyclic hexamer. In nonpolar solvents asupramolecular gel was obtained. Gel-solution transition was achieved by addition ofDAN or hydrogen bonding competitive reagents such as carboxylic acid. In the fourth part, four UPy units were introduced into the tetraphenyl ethyleneskeleton. A supramolecular polymeric network formed via hydrogen bonding betweenUPy units. The rotation about the single bond between phenyls and the double bondwas prohibited and fluorescent emission was observed even at dilution solution. Byaddition of DAN to destroy the hydrogen bonding network, the fluorescence wasquenched.