The Construction Of Copper Nanocluster Supramolecular Self-assembly And Their Properties And Applications

Supramolecular self-assembly has been shown to be a reliable method for the preparation of multifunctional nanomaterials,and its self-assembly process and structure can be controlled by external stimuli,and is widely used in materials science,biomedicine,catalysis and other fields.The forces driving the self-assembly of supramolecular are mainly non-covalent bonds(hydrogen bonding,π-π stacking,solvophobic interaction and host-guest interactions,etc.).Metal nanoclusters,which are made up of a few to hundreds of metal atoms,are gaining popularity due to their unique electronic structure and unusual physicochemical properties.Copper nanoclusters(Cu NCs)have excellent light stability,low toxicity,and good biocompatibility,but their quantum yield is low.In recent years,aggregation induced emission(AIE),first proposed by Tang Benzhong’s research group,has been found to significantly improve the emission intensity and quantum yield of Cu NCs.Inducing Cu NCs self-assembly by supramolecular self-assembly can not only achieve AIE,improve the quantum yield of Cu NCs,but also promote coordination between multiple functions,and enhance their chirality,electrocatalytic and other properties.In addition,Cu NCs assemblies containing light-responsive groups or other functional groups can be modulated by external stimuli.This stimulus-responsive assemblies have potential application prospects in the fields of drug release,fluorescence detection,and biosensing.In summary,the Cu NCs are prepared into functional supramolecular materials by selfassembly,which have great application value and important academic research significance.The main contents of this paper are divided into the following four parts:Part Ⅰ,introduction.The concept and force of self-assembly of supramoleculars are introduced,focusing on solvophobic interaction and π-π stacking;the concept of metal nanoclusters are introduced,focusing on copper nanoclusters and their selfassembly and applications;The concept of aggregation-induced emission(AIE)and the research progress of AIE of metal nanoclusters are summarized,and the optical properties of azobenzene and its optical properties,as well as some light-responsive materials constructed by self-assembly,are introduced.Finally,the research content and significance of this paper are proposed.Part Ⅱ,study on solvent-induced self-assembly of copper nanoclusters and their luminescence properties.The self-assembly behavior of atomically precise Cu4-NCs with triphenylphosphine-terminated was studied.Using a solvent-induced selfassembly strategy,DMSO as a good solvent and glycerol as a poor solvent,Cu4-NCs were self-assembled into branched structures,thus achieving aggregation-induced emission(AIE),thermal activation delayed fluorescence(TADF)and an absolute quantum yield of up to 67.05%.Through structural characterization and optical analysis,we demonstrated that the high compactness of the assembly enhances the cuprophilic interaction and inhibits the intramolecular vibration and rotation of the Cu4-NCs ligand,protecting the Cu core from the quenching of singlet oxygen.These features led to the emergence of TADF and AIE.Further,by mixing the assembly with a commercial phosphor,a white light-emitting diode was prepared.This study shows that the TADF emission and strong light-emitting structure of Cu4-NCs assemblies make them potential applications and expand the research direction of metal NCs in the field of optical devices.Part III,light-induced reversible supramolecular self-assembly of azo copper nanoclusters.Using toluene as a good solvent and methanol as a poor solvent,azo functionalized copper nanoclusters(Cu3-NCs)are self-assembled into rigid nanofibers in a binary solvent mixture.This nanofibers have a reversible light response,which under 365 nm ultraviolet light illumination,due to the cis-and trans-isomerization of Cu3-NCs,rigid fibers become bent,the surface is rough,the order decreases,and the fibers begin to disassemble.On the one hand,this change in morphology is due to the large steric resistance of the cis-Cu3-NCs,which disturbs the tight stacking of fibers.On the other hand,cis-Cu3-NCs have greater polarity and increased solubility in mixed solvents,resulting in the disassembly of the fibers.Under visible light,the cis-Cu3-NCs changes back to the trans-,and the morphology can restore.The one-dimensional selfassemblies with light-triggered,reversible morphological changes achieved in this work can be potentially used as a medium material in an optical information storage device,and can write and erase information through the irradiation of UV light and visible light.Part Ⅳ,the light-responsive self-assembly of azo copper nanoclusters for reversible demulsification/emulsification of emulsions.The azo functionalized copper nanoclusters(Cu3-NCs)were dissolved into the APG0810 emulsion,and the reversible self-assembly of Cu3-NCs was regulated by light,so as to achieve reversible phase separation of the emulsion.Through the dispersion test of the emulsion in water and toluene and laser confocal,it was determined that the prepared emulsion was an oil-inwater emulsion,and the addition of Cu3-NCs did not affect the stability of the emulsion.However,under ultraviolet light,the trans-Cu3-NCs transforms into cis-,and selfassembly into the long fibers,destroying the emulsion droplets,disturbing the stability of the emulsion,resulting in emulsion demulsification.In addition,this emulsification/demulsification can be circulated several times and the fibers at the interface are recyclable.This study shows that metal nanoclusters have potential application prospects in the field of light-responsive emulsions,and the prepared emulsions have potential application value in catalysis,material synthesis and other fields.