Metal-organic frameworks(MOFs)with HKUST-like tbo structures have been paid specific attention for gas sorption and separation because of their specific pore features.According to the geometric similarity of spirobifl...Metal-organic frameworks(MOFs)with HKUST-like tbo structures have been paid specific attention for gas sorption and separation because of their specific pore features.According to the geometric similarity of spirobifluorene and[Cu_(2)(O_(2)CR)_(4)]paddlewheel secondary building units(Cu_(2)SBUs)in HKUST-1,we attempted to rationally construct a HKUST-like MOF by a substitution strategy.Using a judiciously designed octatopic carboxylate ligand,a copper-organic framework,JUC-220,was synthesized.The crystals of JUC-220 exhibited characteristic features in cubic with disorder,possibly due to the disorder substitution and high symmetry of tbo topology.Two related HKUST-like structure models were considered.Thanks to the suitable pore size and specific pore shapes,the adsorption selectivities of JUC-220 for C_(3)H_(8)/CH_(4)(5/85)and C_(2)H_(6)/CH_(4)(10/85)gas mixtures were as high as 736 and 46 respectively at 298 K and 1 bar.Specially,JUC-220 exhibited excellent trace adsorption performance of C_(3)H_(8)and C_(2)H_(6)as well as reverse adsorption behavior of C_(2)H_(6)/C_(2)H_(4).Thus,JUC-220 serves as an example of HKUST-like MOF with disorder for light hydrocarbons separation and the implementation of substitution which can be used to explore more porous MOFs.展开更多
Cationic azole-based metal-organic frameworks(MOFs)with remarkable stability and unique pore environment have aroused great research interests.Meanwhile,flexible MOFs which can undergo pore-structure changes upon expo...Cationic azole-based metal-organic frameworks(MOFs)with remarkable stability and unique pore environment have aroused great research interests.Meanwhile,flexible MOFs which can undergo pore-structure changes upon exposure to external stimuli are ideal materials for gas separation.However,introducing flexibility into the framework of cationic azole-based MOFs is rarely reported.Herein,we synthesized two stable isomorphic cationic MOFs(M-btz-as,M=Co,Ni)based on a linear azole ligand.After activated at high temperature under vacuum,M-btz-ht(M=Co,Ni)were obtained and both MOFs exhibited flexible features in which Co-btz is more flexible than Ni-btz.Different solvent-mediated activation methods were employed to explore their effects on structural flexibility and produced MOFs with different phases.Continuous phase transformation of Co-btz-e was verified by powder X-ray diffraction.In addition,these MOF phases possessed different gas separation abilities affected by their flexible frameworks,and Co-btz-ht exhibited the highest CO_(2)/CH4 separation ability.展开更多
基金This research work was supported by the National Natural Science Foundation of China(Nos.21871105,21975096,and 21501064)。
文摘Metal-organic frameworks(MOFs)with HKUST-like tbo structures have been paid specific attention for gas sorption and separation because of their specific pore features.According to the geometric similarity of spirobifluorene and[Cu_(2)(O_(2)CR)_(4)]paddlewheel secondary building units(Cu_(2)SBUs)in HKUST-1,we attempted to rationally construct a HKUST-like MOF by a substitution strategy.Using a judiciously designed octatopic carboxylate ligand,a copper-organic framework,JUC-220,was synthesized.The crystals of JUC-220 exhibited characteristic features in cubic with disorder,possibly due to the disorder substitution and high symmetry of tbo topology.Two related HKUST-like structure models were considered.Thanks to the suitable pore size and specific pore shapes,the adsorption selectivities of JUC-220 for C_(3)H_(8)/CH_(4)(5/85)and C_(2)H_(6)/CH_(4)(10/85)gas mixtures were as high as 736 and 46 respectively at 298 K and 1 bar.Specially,JUC-220 exhibited excellent trace adsorption performance of C_(3)H_(8)and C_(2)H_(6)as well as reverse adsorption behavior of C_(2)H_(6)/C_(2)H_(4).Thus,JUC-220 serves as an example of HKUST-like MOF with disorder for light hydrocarbons separation and the implementation of substitution which can be used to explore more porous MOFs.
基金supports from the Fundamental Research Funds for the Central Universities(No.2412019FZ008)the National Natural Science Foundation of China(Nos.21871105,21503038 and 21531003)the“111”project(No.B18012).
文摘Cationic azole-based metal-organic frameworks(MOFs)with remarkable stability and unique pore environment have aroused great research interests.Meanwhile,flexible MOFs which can undergo pore-structure changes upon exposure to external stimuli are ideal materials for gas separation.However,introducing flexibility into the framework of cationic azole-based MOFs is rarely reported.Herein,we synthesized two stable isomorphic cationic MOFs(M-btz-as,M=Co,Ni)based on a linear azole ligand.After activated at high temperature under vacuum,M-btz-ht(M=Co,Ni)were obtained and both MOFs exhibited flexible features in which Co-btz is more flexible than Ni-btz.Different solvent-mediated activation methods were employed to explore their effects on structural flexibility and produced MOFs with different phases.Continuous phase transformation of Co-btz-e was verified by powder X-ray diffraction.In addition,these MOF phases possessed different gas separation abilities affected by their flexible frameworks,and Co-btz-ht exhibited the highest CO_(2)/CH4 separation ability.
