Silicogermanate(JU110)with an interrupted open-framework has been synthesized by using a hydrothermal method using 1,1’-(1,4-phenylenebis(methylene))bis(1-methylpyrrolidin-1-ium)hydroxide as an organic structure-dire...Silicogermanate(JU110)with an interrupted open-framework has been synthesized by using a hydrothermal method using 1,1’-(1,4-phenylenebis(methylene))bis(1-methylpyrrolidin-1-ium)hydroxide as an organic structure-directing agent(OSDA).Silicon and fluoride anions were introduced to the concentrated-gel synthesis system,and different synthetic parameters influencing the synthesis were discussed.The structure of JU110 was characterised by using rotation electron diffraction(RED)and high-resolution powder X-ray diffraction.JU110 crystallizes in the space group Fm2m(No.42)with a=13.9117(2)Å,b=18.2980(3)Åand c=32.7800(6)Å.The structure is constructed by the sti layers found in the STI framework that are pillared by D4R/Ge7 units to form a large cavity,showing 10-ring openings along[100]and 9-ring openings along[110].Thermal stability studies showed that the framework was maintained with the loss of water molecules,but collapsed with the removal of charge-compensating cations.展开更多
To overcome the limitations of traditional single-crystal X-ray diffraction(SCXRD)for microcrystalline materials and the peak-overlapping issue of powder X-ray diffraction(PXRD),this study employed cryogenic continuou...To overcome the limitations of traditional single-crystal X-ray diffraction(SCXRD)for microcrystalline materials and the peak-overlapping issue of powder X-ray diffraction(PXRD),this study employed cryogenic continuous rotation electron diffraction(cryo-cRED)with a low-dose strategy to determine the crystal structure of CL30,a novel silicogermanate framework.It is confirmed that CL30 crystallizes in the C2/m space group and has layered topology composed of discontinuous zigzag chains connected by double four-membered ring(d4r)units,with fluoride anions(F^(-))occluded in the d4r units.In CL30,charge balance involves organic structure-directing agent(OSDA)cations,occluded F^(-),and terminal oxygen sites whose protonation state cannot be established from the present three dimensional(3D)ED data.F^(-)encapsulated in the d4r units contributes to charge compensation as the counter-anion to OSDA cations,rather than only balancing the framework charge.Although the refinement indices(R_(1)=0.29,wR_(2)=0.71)exceeded typical small-molecule crystallography standards,the structural model remained highly reliable,as supported by geometric restraints and validation.In electron diffraction,elevated R_(1) values are commonly attributed to the intrinsic factors of the technique,such as dynamic scattering,detector noise from scintillator-based detectors,and TEM stage instability(large spheres of confusion).This study introduces a new structural prototype to the silicogermanate family and establishes a feasible workflow for determining the structures of radiation-sensitive microcrystalline porous materials.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2016YFB0701100)the National Natural Science Foundation of China(Grant No.:21320102001 and 21621001)+2 种基金the 111 Project(B17020)financial support from the Swedish Research Council(VR),the Swedish Governmental Agency for Innovation Systems(VINNOVA)the Knut and Alice Wallenberg Foundation through the project grant 3DEM-NATUR.
文摘Silicogermanate(JU110)with an interrupted open-framework has been synthesized by using a hydrothermal method using 1,1’-(1,4-phenylenebis(methylene))bis(1-methylpyrrolidin-1-ium)hydroxide as an organic structure-directing agent(OSDA).Silicon and fluoride anions were introduced to the concentrated-gel synthesis system,and different synthetic parameters influencing the synthesis were discussed.The structure of JU110 was characterised by using rotation electron diffraction(RED)and high-resolution powder X-ray diffraction.JU110 crystallizes in the space group Fm2m(No.42)with a=13.9117(2)Å,b=18.2980(3)Åand c=32.7800(6)Å.The structure is constructed by the sti layers found in the STI framework that are pillared by D4R/Ge7 units to form a large cavity,showing 10-ring openings along[100]and 9-ring openings along[110].Thermal stability studies showed that the framework was maintained with the loss of water molecules,but collapsed with the removal of charge-compensating cations.
基金supported by the National Natural Science Foundation of China (Grant No.12374021)Beijing Natural Science Foundation (Grant No.1252031)。
文摘To overcome the limitations of traditional single-crystal X-ray diffraction(SCXRD)for microcrystalline materials and the peak-overlapping issue of powder X-ray diffraction(PXRD),this study employed cryogenic continuous rotation electron diffraction(cryo-cRED)with a low-dose strategy to determine the crystal structure of CL30,a novel silicogermanate framework.It is confirmed that CL30 crystallizes in the C2/m space group and has layered topology composed of discontinuous zigzag chains connected by double four-membered ring(d4r)units,with fluoride anions(F^(-))occluded in the d4r units.In CL30,charge balance involves organic structure-directing agent(OSDA)cations,occluded F^(-),and terminal oxygen sites whose protonation state cannot be established from the present three dimensional(3D)ED data.F^(-)encapsulated in the d4r units contributes to charge compensation as the counter-anion to OSDA cations,rather than only balancing the framework charge.Although the refinement indices(R_(1)=0.29,wR_(2)=0.71)exceeded typical small-molecule crystallography standards,the structural model remained highly reliable,as supported by geometric restraints and validation.In electron diffraction,elevated R_(1) values are commonly attributed to the intrinsic factors of the technique,such as dynamic scattering,detector noise from scintillator-based detectors,and TEM stage instability(large spheres of confusion).This study introduces a new structural prototype to the silicogermanate family and establishes a feasible workflow for determining the structures of radiation-sensitive microcrystalline porous materials.
