Syntheses,Structures And Properties Of D¹⁰ Metal/Lanthanide MOFs Based On Carboxylic Acid Ligands

Metal-Organic Frameworks?MOFs?as a new type of multifunctional material have attracted widespread attention owing to their excellent properties in various fields including luminescence,electricity,magnetism and biomedicine,etc.Based on the principle of crystal engineering,we have started from the performance of MOFs,and mainly studied the synthesis,structure and properties of d¹⁰ transition metal/lanthanide MOFs in this paper.In addition,we have explored regulation/guiding effect of metal ions and carboxylic acid ligands on the structure of MOFs.The main research work has the following four systems:1.Syntheses,Structures and Properties of Novel d¹⁰ Transition Metal MOFs Based on a Single N-carboxylic Acid LigandThree d¹⁰-MOFs[Zn?ant?₂]_n?Zn-ant?,[CdBa?aip?₂?H₂O?₂]_n?CdBa-aip?and[Cd₃?aip?₂?C₂O₄??H₂O?₆]_n?Cd-aipox?have been constructed through 5-aminonicotinic acid?Hant?,5-aminoisophthalic acid?H₂aip?and d¹⁰ transition metals under hydrothermal conditions.The single-crystal structure shows that these three MOFs have been composed of2D network layers through metal ions and organic ligands bridging,and formed 3D supramolecular frameworks by hydrogen bonding interactions.At the same time,they have good thermal stability and excellent luminescence properties.Furthermore,the influence of the different deprotonating reagents on the assemblies of MOFs based on 5-aminoisophthalic acid is far less explored.2.Syntheses,Structures and Properties of Novel d¹⁰ Transition Metal MOFs Based on Two N-Carboxylate Acid LigandsBased on the synthesis strategy of mixed ligands,with 5-aminonicotinic acid,terephthalic acid?H₂BDC?and 2,5-dichloroisonicotinic acid?HL?as the main organic ligands,introducing auxiliary ligand 4,4?-bipyridine?bipy?and 1,10-phenanthroline,four d¹⁰-MOFs[Zn?ant?₂?phen?]_n?Zn-ant-phen?,[ZnL₂?bipy?]_n?Zn-L-bipy?,[Zn?BDC??phen??H₂O?]_n?Zn-BDC-phen?,and[Cd?BDC??phen?]_n?Cd-BDC-phen?have been synthesized under hydrothermal/solvothermal conditions.Structural analysis shows that these four complexes are one-dimensional chain structures.In addition,the photoluminescent performance of Zn-ant-phen and Zn-L-bipy were better.3.Syntheses,Structures and Properties of Cage-like Clusters Ln-MOFs Based on3,3-Dimethylcyclopropane-1,2-dicarboxylic AcidA new family of octagonal-prismatic cage-like clusters Ln-MOFs,formulated as[Ln??₃-OH?₈][Ln₁₆??₄-O???₄-OH???₃-OH?₈?H₂O?₈??₄-dcd?₈][??₃-dcd?₈]·22H₂O?here,it is denoted as UJN-Ln,UJN=University of Jinan;Ln=Gd,Tb,Dy,Ho and Er;dcd=3,3-dimethylcyclopropane-1,2-dicarboxylate dianion?,have been assembled from lanthanide ions and the ligand H₂dcd under hydrothermal conditions.It should be pointed out that the H₂dcd is derived from the in-situ hydrolysis reaction of 6,6-dimethyl-3-oxabicyclo[3.1.0]hexane-2,4-dione?DMOHD?.The performance test shows that UJN-Tb displays excellent luminescence and UJN-Dy exhibits slow magnetic relaxation associated with SMMs.More importantly,UJN-Gd possesses a large MCE(-?S_m=42.3 Jkg^-1K^-1 for?H=7.0 T at 2.0 K)and is expected to be a promising candidate as a molecule-based magnetocaloric refrigerant.4.Syntheses,Structures and Properties of Wheel-shaped Clusters Ln-MOFs Based on3,3-Dimethylcyclopropane-1,2-dicarboxylic AcidOn the basis of the previous system,by changing the reaction conditions,the first example of 3D porous wheel clusters Ln-MOFs[Ln₄??₄-dcd?₆?H₂O?]?UJN-Ln4,Ln=Sm,Eu,Gd and Tb?have been successfully constructed.The structural analysis indicates that UJN-Ln4 has a special structure with unique hydrophilic and hydrophobic pores coexisting.The performance test shows that UJN-Ln4 has high water stability and selective gas/vapor adsorption performance.Furthermore,UJN-Eu4 has highly sensitive toward trace amounts of Fe³⁺,Cu²⁺ions and sodium dodecyl benzenesulfonate?SDBS?in aqueous solutions by fluorescence sensing.Magnetic studies of UJN-Gd4 reveal the presence of significant magnetocaloric effect and coexistence of competitively ferro-and antiferromagnetic exchange interactions between the constituent Gd³⁺ions.