Syntheses, Structures And Properties Of Polynuclear Metal Complexes

Polynuclear metal complexes are enjoying widespread current interest not onlybecause of their nanoscale and aesthetically pleasing molecular structures but alsobecause of their interesting luminescent,electronic,magnetic,and catalytic properties.However,most of the works have so far been focused on polynuclear transistion metalcomplexes,while polynuclear lanthanide or heterometallic 3d-4f clusters have seldomexplored.In the thesis,we reported the syntheses,structures and properties ofPOMs-based complexes,lanthanide polynuclear clusters and 3d-4f polynuclearclusters.The findings are following:â… :Controlled assembly of POM-based coordination complexes.(1) FiveKeggin-based coordination complexes(1-5) ranged from 0D to 3D structures and twocompounds(6-7) were obtained by merely increasing the pH value,respectively;(2)Two Dawson-based complexes(8-9) were synthesized under different anions.Byanalyzing the details of the structure,it showing that the pH value and anions of thereaction play crucial roles in controlling the topological structures of thesupramolecular architectures.â…¡:Construction of POM-based complexes through electrostatic incorporation.FourPOMs-based coordination polymers (10-13) were prepared through directincorporation between POMs and 2D network.Crystal structural analysis reveals thatthe relationship between the size of the void of 2D network and that of POMs isimportance for successful synthesis of POMs-based open metal-organic frameworks.â…¢Polynuclear lanthanide clusters.(1) The largest members hitherto known ofhomonuclear lanthanide clusters,Ln₆₀(14-17),have been obtained from the hydrolysisof Ln(â…¢) ions controlled by ancillary threonine ligands.Structure analysis shows thatthe templating anions play crucial role in formation of high-nuclear clusters;(2)Tetranuclear(18-19) and Octanuclear(20-21) lanthanide hydroxide complexes havebeen synthesized,respectively,by controlled hydrolysis of the lanthanide ions usingnicotinic acid under different synthetic procedure. â…£:Coordination polymers based on polynuclear lanthanide clusters.(1) A 3Dporous coordination polymer(22) based on hexanuclear lanthanide clusters and1D(24),2D(23) coordination complexes consisted of dinuclear lanthanide units weresynthesized using nitrilotripropionic acid by changing the pH value,respectively;(2)A 3D cation framework(25-34) with 1D channel was synthesized.Investigation on theselectivity of the cation framework for anions reveals that guest water molecules playan important role in the selective separation of anions in the metal-organic framework.â…¤:High-nuclearity lanthanide-transistion metal clusters.Four series ofheterometallic high-nuclearity complexes featuring Ln₂₀Ni₂₁ (35-36),Ln₂₀Ni₃₀ (37-38),Gd₅₄Ni₅₄ (39) and Ln₅₂Ni₅₆ (40-44),Ln₆₀Ni₇₆ (45)were prepared from iminodiaceticacid.Ln₂₀Ni₃₀ clusters feature a dual shell-like core of the Keplerate type^â… .Gd₅₄Ni₅₄and Ln₅₂Ni₅₆ possess four-shell,nesting doll-like four-shell,nesting framework.Ln₆₀Ni₇₆ is the largest member hitherto known of 3d-4f clusters.That clusters of fourdistinct types were obtained indicates that the anion decomposed from ligands plays akey role in the formation of high-nuclearity complexes.â…¥:Coordination complexes based on polynuclear 3d-4f Clusters.(1) Usingmetalloligand and second organic ligand as building block in association withlanthanide cations,we have synthesized three structural kinds of 3d-4f MOFs (46-54),featuring"Ln₆Ni₄","Ln₆Ni₂"and"Ln₆Ni₄+Ln₆Ni₂"units respectively.The structuraldifferences of the complexes reveal that the shape and dimensions of the channels ofMOFs may be changed by adjusting the reaction conditions;(2) A 3D Zeolite-likecoordination polymer(67) featuring two dual cage-like MOPs"Ln₁₂Ni₂₄"and"Ln₂₄Ni₁₂",were synthesized based on HaCDTA ligand.Meanwhile,series of lanthanide coordination polymers (55--66) and mixed-valenceCu^â… Cu^â…¡complexes (68-69) were also obtained.