| Metal-organic frameworks?MORFs?are new type crystal materials which are obtained by combining mechanically interlocked molecules?MIMs?with macrocyclic molecule,metal ions or metal clusters.Because of their designed and fascinating structures and excellent properties,MORFs have attracted increasing attention in recent years.Due to the introduction of macrocyclic molecules,MORFs usually have more functional sites than the traditional metal-organic frameworks?MOFs?,which also determine that have greater advantages in molecular recognition and separation,gas adsorption and storage,and catalysis.In this paper,several new MORFs have been obtained by combing cucurbit[6]uril?CB[6]?-based pseudorotaxane,different transition metal cations and rigid carboxylate ligands based on multiple synthesis strategies.The effects of different reaction temperature,pH,auxiliary ligand length,the counter ions type of the pseudorotaxane and the metal ions on structures of MOFs are discussed,and the relationship between the structure and properties of these compounds is also analyzed.In this paper,based on mixed ligands strategy,8 high dimensional metal-organic rotaxane frameworks have been obtained by hydrothermal,solvothermal and pure solvothermal methods and were characterized by single crystal X-ray diffraction,X-ray powder diffraction,UV,IR,elemental analysis,thermogravimetric,NMR and fluorescence spectrum.The fluorescence sensing and photocatalysis properties of some compounds which are selected have been studied.The solvent exchange kinetics of compound 8 with open channel was studied by NMR and single crystal.1.A cucurbit[6]uril-based[PR43]2+·2[NO3]-with terminal pyridine nitrogen atom was designed and synthesized.Based on mixed ligand strategy,four novel high-dimensional MORFs were successfully fabricated by CB[6]-based pseudorotaxanes?[PR43]?and rigid carboxylate ligands by adjusting the synthesis temperature and the length of ligands in H2O/DMF?3:1?.[Cd4?PR43?2?BDC?2Cl4]·7H2O?1?[Cd2?PR43??BDC?2Cl2]·8H2O?2?[Cd3(PR43]?BPDC?2?COO?2Cl2]·6H2O?3?[Cd3(PR43]2?BPDC?3Cl4]·10H2O?4?Compound 1 represents a three periodic 2-fold interpenetrating dia network based on a binuclear{Cd2Cl4O4}second building unit?SBU?.2 and 3 are isostructural pcu networks constructed by binuclear and trinuclear cadmium clusters,respectively,while compound 4 is a two-dimensional layered network.The solid fluorescence properties of the compounds 1-4 also have been investigated.Comparing the structures of 1,2,3 and 4,we discovered that the coordination sphere of metal clusters in MORFs can be tuned by changing temperatures and the length of auxiliary ligands.The fluorescence sensing properties of compound 1 were investigated in detail,and we found that compound 1 is a potential photoactive material.2.Three new high-dimensional MORFs were successfully synthetized by combining the CB[6]-based[PR43]2+·2[NO3]-and the auxiliary carboxylic ligands with different geometries and Co?II?metal ions by hydrothermal strategy.[Co?PR43?0.5?BDC?Cl]·H2O?5?[Co?PR43?0.5?BTC?]·4H2O?6?[Co?PR43?0.5?BPT?]·16H2O?7?The effect of triethylamine in the crystallization was investigated.The crystal can't be obtained without triethylamine.Triethylamine might well destroy the interaction between the macrocyclic molecule CB[6]and the guest molecule and increase the flexibility of pseudorotaxanes which is more favorable for obtaining the crystal.Compound 5 is a two-dimensional layered structure which is connected by mononuclear cobalt.6 and 7 are three dimensional MORFs contain mononuclear cobalt as node.UV-visible absorption spectrum analysis showed that compound 5-7semiconductor materials.Thus,compound 5 has been applied in CO2 reduction under visible light.This is also the first example of CB[6]-based MORF which is applied in visible light catalysis.3.A water soluble cucurbit[6]uril-based[PR43]2+·2[NO3]-with terminal pyridine nitrogen atom was designed and synthesized.[PR44]2+·2[PF6]-was obtained by simple ion exchange and was easily soluble in organic solvents.Solvothermal reaction of CuCl2,H2BDC and[PR44]2+·2[PF6]-yielded a MORF material,which is the first example three-dimensional?3D?porous CB[6]-based MORF.[Cu2?PR44?0.5?BDC?2Cl]·3DMF?8?Proton conductivity of compound 8 was also investigated to explore significance of incorporation of CB[6]-based pseudorotaxanes into CB[6]-based MORFs and and compound 8 exhibits high relatively proton conductivity.By exploring,we found that3 DMFs in compound 8 were readily replaced by benzenes to generate the new host-guest system of compound 9.[Cu2?PR44?0.5?BDC?2Cl]·2.5Ph?9?The kinetics of guest exchange in 8 has been probed and confirmed by NMR and X-ray crastallography.First,the DMFs in compound 8 can be completely exchanged by benzene after 10 hours which is probed by NMR.Guest exchange in 8 also has been confirmed by X-ray crastallography.2.5 benzene molecules are arranged orderly in the structure of 9 in each cell,which further validates the previous conclusion. |
PDF Full Text Request