Luminescent Hybrid Nanomaterials Constructed From Gold Nanoparticles And Lanthanide Complexes With ?-diketonate And Terpyridine Derivative Ligands

The combination of lanthanides and nanoparticles to develop new hybrid nanomaterials has become a highly topical area of research in the field of sensing,biomedical imaging,drug delivery,etc.However,these novel nanomaterials have to be carefully designed to ensure that the unique properties conveyed by each component,i.e.,lanthanide ions and nanoparticles,are maximized and not negatively affected by one another.In the present study,novel luminescent hybrid nanomaterials constructed from gold nanoparticles?AuNPs?and lanthanide complexes?LnL₃?HSTPY??with?-diketonate?HL?and terpyridine derivative?HSTPY?ligands were synthesized?denoted as AuNP-STPY-LnL₃?through the self-assembly of a functional organic ligand HSTPY with luminescent precursores LnL₃?Ln=Eu,Tb,Nd?tethered to the gold surface via a C₈ alkyl thiol spacer.We further demonstrate that Eu?III?emission arising from the self-assembly sensitizing antennae on AuNPs surface can be switched“on-off”in a reversible manner over several cycles as a function of the pH value,enabling AuNPs-STPY-Eu?tta?₃ to function as a supramolecular switch.The text is divided into the following three chapters:Chapter 1:Firstly,introduced the concept of nanomaterials and elaborated their properties in detail to make a preliminary understanding of nanomaterials;Secondly,a branch of nanomaterials,gold nanoparticles,is introduced emphatically,including its special properties and common preparation methods;Finally,the research progress of the functionalized luminescent gold nanoparticles in Gunlaugsson's research group in recent years is summarized detailedly.Chapter 2:Multifunctional ligand 8-?4-?[2,2?:6?,2?-terpyridin]-4?-yl?phenoxy?octane-1-thiol?HSTPY?was prepared by multi-step reactions.The ligand was coated on the surface of gold nanoparticles with the thiol group at the end of HSTPY through Brust-Schiffin two-phase method and ligand substitution method.UV-Vis,TEM and DLS were used to determine the formation of monodisperse spherical gold nanoparticles:AuNPs-STPY.After that,luminescent precursor complexes,LnL₃?H₂O?₂,constructed with?-diketone ligands and Ln???were synthesized,and self-assembled with free ligand HSTPY and modified ligand coated on the surface of AuNPs to form luminescent ternary complexes LnL₃?HSTPY?and AuNPs-STPY-LnL₃,respectively?Ln=Eu,Nd,HL=Htta;Ln=Tb,HL=Htfacac?.Finally,the fluorescence properties of LnL₃?H₂O?₂,LnL₃?HSTPY?and AuNPs-STPY-LnL₃ were compared by various methods.Chapter 3:The energy transfer mechanism of Eu?tta?₃?HSTPY?with remarkable luminescence performance was analyzed and explained.The root cause of fluorescence quenching of Eu?tta?₃?HSTPY?complex was investigated through solvent effect and anion sensing experiment.Finally,the fluorescence"on-off"conversion effect and pH response of Eu?tta?₃?HSTPY?and AuNPs-STPY-Eu?tta?₃ with the change of pH were investigated.