Syntheses,Structures And Assemblies Of High-nuclearity Lanthanide-Transition Metal Clusters LnNi₁₂ Based On Polyoxometalates

The assembly of high-nuclearity lanthanide-transition metal clusters remains a great challenge for synthetic chemistry,especially in high-nuclearity lanthanide-transition metal clusters based on polyoxometalates.In this dissertation,entitled"Syntheses,Structures and Assembles of Lanthanide-Transition Metal clusters LaNi₁₂based on Polyoxometalates",a series of high-nuclearity lanthanide-transition metal clusters with LaNi₁₂ units were obtained based on the"slow release strategy of lanthanide ions and in situ formation of lacunary polyoxometalates".What's more,the preliminary study on the structures and properties of these clusters was carried out.The details are as follows:1.Syntheses,Structures and Properties of High-nuclearity Lanthanide-Transition Metal Cluster LaNi₁₂ and La₁₀Ni₄₈ based on Polyoxometalates:The cluster LaNi₁₂ was obtained by the synthetic strategy of "slow release of lanthanide ions and in situ formation of polyoxometalates".After that,the cluster La₁₀Ni₄₈ was synthesized by adjusting the pH,which is the tetramer of LaNi₁₂.Among them,LaioNias is the largest 3d-4f cluster in polyoxometalates chemistry.High resolution electrospray ionization mass spectrometry?HRESI-MS?analysis indicated that the LaNi₁₂ and LaioNias clusters have high stability in water.Additionally,the proton performance study showed that the proton conductivity of the cluster La₁₀Ni₄₈ was about 2.05×10^-2 S cm^-1 at T=295 K and RH=100%,which is one of the best proton conductors among on polyoxometalates-based materials at room temperature.2.Syntheses,Structures and Magnetic Properties of High-nuclearity Lanthanide-Transition Metal Clusters Ln₂Ni₂₄?Ln=La/Nd/Eu?based on Polyoxometalates:Based on the synthetic method of the cluster LaNi₁₂,three clusters of La₂Ni₂₄,Nd₂Ni₂₄ and Eu₂Ni₂₄were obtained by adjusting the ratio of experimental materials.These three clusters have the same structure except that the lanthanide species are different.They can be regarded as a dimer of LnNi₁₂ in structure,and two LnNi₁₂ are connected by{SbO₄} unit,indicating that LnNi₁₂ is an ideal secondary building block.Therefore,it strongly demonstrated that the slow release of lanthanide ions and in situ formation of polyoxometalates is an effective synthetic idea for 3d-4f heterometallic clusters based on polyoxometalates.What's more,the magnetic properties of these clusters were charactered in our work.