Study On Supramolecular Assemblies Based On Pentaerythritol-derived Oxyspirocyclic Diacetals

A spiro compound is a compound in which two monocyclic rings share a carbon atom,and the shared carbon atom is the spiro atom.The spiro compound has the advantages of strong rigidity,small molecular weight,and stable structure.The oxo-spirocyclic compounds obtained by the acetalization of pentaerythritol is a classic representative of the spiro compound.Because of its two oxygen-containing six-membered rings perpendicular to each other conformational advantages and properties,it has many applications in pesticides,medicines,and polymer materials.This thesis aims to design and synthesize a series of novel and functional oxaspiro compounds based on pentaerythritol bisacetal,and to study their supramolecular assembly behavior.This thesis is mainly divided into the following three parts:Part 1,we designed and synthesized an acetal-based oxo-spirocycle bridged ditopic TPE monomer molecule(DTPE),using this monomer as a donor and Nile Red as an acceptor.In the presence of an aqueous solution of cetyltrimethylammonium bromide(CTAB),a light-harvesting system has been successfully constructed from the three small organic molecules through self-assembly.Due to the rigid framework of DTPE,Nile Red could be self-assembled into nano-sphere particles in aqueous solution,and the system exhibits ultra-high antenna effect,and can also achieve tunable emission including bright white light emission.When the molar ratio of donor/acceptor is 250/1,the antenna effect reaches 66.When DTPE is used as the donor molecule,DBT is used as the acceptor molecule I,and NDI is used as the acceptor molecule II,in the presence of the surfactant CTAB aqueous solution,the two-step continuous energy transfer can be preliminarily realized.Part 2,we designed and synthesized isoheptyl ureidopyrimidinone(UPy)precursor and n-butyl UPy precursor,and then synthesized spirocyclic structures through a series of reactions using ortho,meta,and p-nitrobenzaldehyde and pentaerythritol as raw materials.Three amino-substituted oxaspiro ring intermediates,were reacted with activated UPy precursors in chloroform solution to afford several UPy-based oxaspiro ring supramolecular monomers.Due to the quadruple hydrogen bond of UPy,by studying the assembly behavior of the target molecules,we have a better understanding of the role of the quadruple hydrogen bond.Part 3,on the basis of the above work,we further studied the influence of the electron effect of substituents on the yield of oxaspiro compounds based on pentaerythritol acetal.It is found that the yields of oxo-spirocyclic compounds were affected by electron effect.Some electron-rich groups may even prevent the reaction,while some oxo-spirocyclic compounds substituted with electron-withdrawing groups have higher yields.In addition,on the basis of the oxo-spirocycle compounds of the symmetrical pentaerythritol acetal,the oxo-spirocycle compounds of the asymmetric pentaerythritol acetal was further designed and synthesized,and the investigation of specific properties are in due course.