Change search
Refine search result
1 - 23 of 23
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Carson, Fabian
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Su, Jie
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Platero-Prats, Ana E.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Wan, Wei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Yun, Yifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Samain, Louise
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Framework Isomerism in Vanadium Metal-Organic Frameworks: MIL-88B(V) and MIL-101(V)2013In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 13, no 11, p. 5036-5044Article in journal (Refereed)
    Abstract [en]

    Two families of metal organic frameworks (MOFs), MIL-88 and MIL-101 built by trinuclear transition metal (TM) clusters (TM = Cr, Fe, or Sc), have been known for several years, but their syntheses are often reported separately. In fact, these MOFs are polymorphs, or framework isomers: they are assembled from the same metal secondary building units and organic linkers, but the connectivity of these components differs. Here we report for the first time the synthesis of the vanadium MOF MIL-88B(V) and compare its synthesis parameters to those of MIL-47(V) and the recently reported MIL-101(V). The properties of MIL-88B(V) and MIL-101(V) are remarkably different. MIL-88B(V) can breathe and is responsive to different solvents, while MIL-101(V) is rigid and contains mesoporous cages. MIL-101(V) exhibits the highest specific surface area among vanadium MOFs discovered so far. In addition, both MIL-88B(V) and MIL-101(V) transform to MIL-47 at higher temperatures. We have also identified the key synthesis parameters that control the formation of MIL-88B(V), MIL-101(V), and MIL-47: temperature, time, and pH. This relates to the rate of reaction between the metal and linkers, which has been monitored by ex situ X-ray powder diffraction and V K-edge X-ray absorption spectroscopy during MOF synthesis. It is therefore important to fully study the synthesis conditions to improve our understanding of framework isomerism in MOFs.

  • 2.
    Fang, Liang
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Liu, Leifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Yun, Yifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Inge, A. Ken
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Wan, Wei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Geo, Feifei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    SU-77: An Open-Framework Germanate Containing 12 × 10 × 10-Ring Channels Solved by Combining Rotation Electron Diffraction and Powder X-ray Diffraction2014In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 14, no 10, p. 5072-5078Article in journal (Refereed)
    Abstract [en]

    A novel open-framework germanate, denoted as SU-77, was prepared by hydrothermal synthesis using ethylenediamine as the structure directing agent. The as-synthesized SU-77 is monoclinic with space group P21/a and a = 13.52427(5) Å, b = 12.64862(5) Å, c = 9.60578(3) Å, β = 92.8599(4)°. The structure of SU-77 is built from a novel Ge6O17(C2H8N2)F (Ge6) cluster building unit. The Ge6 clusters are connected to form chains along the c-axis. These chains are further connected in the [110] and [1–10] directions to form a three-dimensional framework with 12 × 10 × 10-ring channels. The as-synthesized monoclinic SU-77 became orthorhombic while being observed in a transmission electron microscope (TEM) or when heated to 200 °C in air. The orthorhombic structure of SU-77 was solved from micrometer-sized crystals by rotation electron diffraction (RED). The monoclinic structure was built from the orthorhombic structure and subsequently refined against synchrotron powder X-ray diffraction data. SU-77 is the first example of an open-framework germanate with mixed coordination polyhedra solved by electron diffraction.

  • 3.
    Guo, Peng
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Chinese Academy of Sciences, China.
    Afeworki, Mobae
    Cao, Guang
    Yun, Yifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Su, Jie
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Wan, Wei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Synthesis and Structure of a Layered Fluoroaluminophosphate and Its Transformation to a Three-Dimensional Zeotype Framework2018In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 57, no 18, p. 11753-11760Article in journal (Refereed)
    Abstract [en]

    Two-dimensional zeolitic materials have drawn increasing attention because of their structural diversity, high accessible surface areas, and potential as precursors to form novel three-dimensional (3D) structures. Here we report a new layered fluoroaluminophosphate, denoted as EMM-9 (ExxonMobil Material #9), synthesized in the same synthesis system as that for a previously reported 3D framework structure EMM-8 (framework-type code: SFO) using an F- medium and 4-(dimethylamino)pyridine (DMAP) as the organic structure-directing agent. The structure of EMM-9 was solved from rotation electron diffraction data and refined against synchrotron powder X-ray diffraction data. The fluoroaluminophosphate layer of EMM-9 is composed of sti composite building units. The DMAP cations are located between the layers. pi-pi interactions between the DMAP cations and hydrogen bonding between the DMAP cations and layers were identified. The layered EMM-9 structure is closely related to the 3D framework structure of EMM-8 and can be transformed to EMM-8 by calcination.

  • 4.
    Guo, Peng
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Liu, Leifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Yun, Yifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Su, Jie
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Wan, Wei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Gies, Hermann
    Zhang, Haiyan
    Xiao, Feng-Shou
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Ab initio structure determination of interlayer expanded zeolites by single crystal rotation electron diffraction2014In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 43, no 27, p. 10593-10601Article in journal (Refereed)
    Abstract [en]

    Layered solids often form thin plate-like crystals that are too small to be studied by single-crystal X-ray diffraction. Although powder X-ray diffraction (PXRD) is the conventional method for studying such solids, it has limitations because of peak broadening and peak overlapping. We have recently developed a software-based rotation electron diffraction (RED) method for automated collection and processing of 3D electron diffraction data. Here we demonstrate the ab initio structure determination of two interlayer expanded zeolites, the microporous silicates COE-3 and COE-4 (COE-n stands for International Network of Centers of Excellence-n), from submicron-sized crystals by the RED method. COE-3 and COE-4 are built of ferrierite-type layers pillared by (-O-Si(CH3)(2)-O-) and (-O-Si(OH)(2)-O-) linker groups, respectively. The structures contain 2D intersecting 10-ring channels running parallel to the ferrierite layers. Because both COE-3 and COE-4 are electron-beam sensitive, a combination of RED datasets from 2 to 3 different crystals was needed for the structure solution and subsequent structure refinement. The structures were further refined by Rietveld refinement against the PXRD data. The structure models obtained from RED and PXRD were compared.

  • 5.
    Hao, Wenming
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Björkman, Eva
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Yun, Yifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Lilliestråle, Malte
    Hedin, Niklas
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Iron Oxide Nanoparticles Embedded in Activated Carbons Prepared from Hydrothermally Treated Waste Biomass2014In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, no 3, p. 875-882Article in journal (Refereed)
    Abstract [en]

    Particles of iron oxide (Fe3O4; 20-40nm) were embedded within activated carbons during the activation of hydrothermally carbonized (HTC) biomasses in a flow of CO2. Four different HTC biomass samples (horse manure, grass cuttings, beer production waste, and biosludge) were used as precursors for the activated carbons. Nanoparticles of iron oxide formed from iron catalyst included in the HTC biomasses. After systematic optimization, the activated carbons had specific surface areas of about 800m(2)g(-1). The pore size distributions of the activated carbons depended strongly on the degree of carbonization of the precursors. Activated carbons prepared from highly carbonized precursors had mainly micropores, whereas those prepared from less carbonized precursors contained mainly mesopores. Given the strong magnetism of the activated carbon-nano-Fe3O4 composites, they could be particularly useful for water purification.

  • 6. Jiang, Jiuxing
    et al.
    Yun, Yifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Jorda, Jose Luis
    Corma, Avelino
    ITQ-54: a multi-dimensional extra-large pore zeolite with 20 [times] 14 [times] 12-ring channels2015In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 6, p. 480-485Article in journal (Refereed)
    Abstract [en]

    A multi-dimensional extra-large pore silicogermanate zeolite, named ITQ-54, has been synthesised by in situ decomposition of the N,N-dicyclohexylisoindolinium cation into the N-cyclohexylisoindolinium cation. Its structure was solved by 3D rotation electron diffraction (RED) from crystals of ca. 1 [small mu ]m in size. The structure of ITQ-54 contains straight intersecting 20 [times] 14 [times] 12-ring channels along the three crystallographic axes and it is one of the few zeolites with extra-large channels in more than one direction. ITQ-54 has a framework density of 11.1 T atoms per 1000 A3, which is one of the lowest among the known zeolites. ITQ-54 was obtained together with GeO2 as an impurity. A heavy liquid separation method was developed and successfully applied to remove this impurity from the zeolite. ITQ-54 is stable up to 600 [degree]C and exhibits permanent porosity. The structure was further refined using powder X-ray diffraction (PXRD) data for both as-made and calcined samples.

  • 7. Martinez-Franco, Raquel
    et al.
    Moliner, Manuel
    Yun, Yifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Peking University, China.
    Wan, Wei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Corma, Avelino
    Synthesis of an extra-large molecular sieve using proton sponges as organic structure-directing agents2013In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 110, no 10, p. 3749-3754Article in journal (Refereed)
    Abstract [en]

    The synthesis of crystalline microporous materials containing large pores is in high demand by industry, especially for the use of these materials as catalysts in chemical processes involving bulky molecules. An extra-large-pore silicoaluminophosphate with 16-ring openings, ITQ-51, has been synthesized by the use of bulky aromatic proton sponges as organic structure-directing agents. Proton sponges show exceptional properties for directing extra-large zeolites because of their unusually high basicity combined with their large size and rigidity. This extra-large-pore material is stable after calcination, being one of the very few examples of hydrothermally stable molecular sieves containing extra-large pores. The structure of ITQ-51 was solved from submicrometer-sized crystals using the rotation electron diffraction method. Finally, several hypothetical zeolites related to ITQ-51 have been proposed.

  • 8. Martinez-Franco, Raquel
    et al.
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Sastre, German
    Yun, Yifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Moliner, Manuel
    Corma, Avelino
    Supra-molecular assembly of aromatic proton sponges to direct the crystallization of extra-large-pore zeotypes2014In: Proceedings of the Royal Society. Mathematical, Physical and Engineering Sciences, ISSN 1364-5021, E-ISSN 1471-2946, Vol. 470, no 2166Article in journal (Refereed)
    Abstract [en]

    The combination of different experimental techniques, such as solid C-13 and H-1 magic-angle spinning NMR spectroscopy, fluorescence spectroscopy and powder X-ray diffraction, together with theoretical calculations allows the determination of the unique structure directing the role of the bulky aromatic proton sponge 1,8-bis(dimethylamino)naphthalene (DMAN) towards the extra-large-pore ITQ-51 zeolite through supra-molecular assemblies of those organic molecules.

  • 9.
    Pascanu, Vlad
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Yao, Qingxia
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Bermejo Gomez, Antonio
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Gustafsson, Mikaela
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Yun, Yifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Wan, Wei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Samain, Louise
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Martin-Matute, Belen
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sustainable Catalysis: Rational Pd Loading on MIL-101Cr-NH2 for More Efficient and Recyclable Suzuki-Miyaura Reactions2013In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 19, no 51, p. 17483-17493Article in journal (Refereed)
    Abstract [en]

    Palladium nanoparticles have been immobilized into an amino-functionalized metal-organic framework (MOF), MIL-101Cr-NH2, to form Pd@MIL-101Cr-NH2. Four materials with different loadings of palladium have been prepared (denoted as 4-, 8-, 12-, and 16wt%Pd@MIL-101Cr-NH2). The effects of catalyst loading and the size and distribution of the Pd nanoparticles on the catalytic performance have been studied. The catalysts were characterized by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, powder X-ray diffraction (PXRD), N-2-sorption isotherms, elemental analysis, and thermogravimetric analysis (TGA). To better characterize the palladium nanoparticles and their distribution in MIL-101Cr-NH2, electron tomography was employed to reconstruct the 3D volume of 8wt%Pd@MIL-101Cr-NH2 particles. The pair distribution functions (PDFs) of the samples were extracted from total scattering experiments using high-energy X-rays (60keV). The catalytic activity of the four MOF materials with different loadings of palladium nanoparticles was studied in the Suzuki-Miyaura cross-coupling reaction. The best catalytic performance was obtained with the MOF that contained 8wt% palladium nanoparticles. The metallic palladium nanoparticles were homogeneously distributed, with an average size of 2.6nm. Excellent yields were obtained for a wide scope of substrates under remarkably mild conditions (water, aerobic conditions, room temperature, catalyst loading as low as 0.15mol%). The material can be recycled at least 10times without alteration of its catalytic properties.

  • 10.
    Singh, Devinder
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Yun, Yifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Wan, Wei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Grushko, Benjamin
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Hovmöller, Sven
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    A complex pseudo-decagonal quasicrystal approximant, Al-37(Co,Ni)(15.5), solved by rotation electron diffraction2014In: Journal of applied crystallography, ISSN 0021-8898, E-ISSN 1600-5767, Vol. 47, no 1, p. 215-221Article in journal (Refereed)
    Abstract [en]

    Electron diffraction is a complementary technique to single-crystal X-ray diffraction and powder X-ray diffraction for structure solution of unknown crystals. Crystals too small to be studied by single-crystal X-ray diffraction or too complex to be solved by powder X-ray diffraction can be studied by electron diffraction. The main drawbacks of electron diffraction have been the difficulties in collecting complete three-dimensional electron diffraction data by conventional electron diffraction methods and the very time-consuming data collection. In addition, the intensities of electron diffraction suffer from dynamical scattering. Recently, a new electron diffraction method, rotation electron diffraction (RED), was developed, which can overcome the drawbacks and reduce dynamical effects. A complete three-dimensional electron diffraction data set can be collected from a sub-micrometre-sized single crystal in less than 2 h. Here the RED method is applied for ab initio structure determination of an unknown complex intermetallic phase, the pseudo-decagonal (PD) quasicrystal approximant Al-37.0(Co,Ni)(15.5), denoted as PD2. RED shows that the crystal is F-centered, with a = 46.4, b = 64.6, c = 8.2 angstrom. However, as with other approximants in the PD series, the reflections with odd l indices are much weaker than those with l even, so it was decided to first solve the PD2 structure in the smaller, primitive unit cell. The basic structure of PD2 with unit-cell parameters a = 23.2, b = 32.3, c = 4.1 angstrom and space group Pnmm has been solved in the present study. The structure with c = 8.2 angstrom will be taken up in the near future. The basic structure contains 55 unique atoms (17 Co/Ni and 38 Al) and is one of the most complex structures solved by electron diffraction. PD2 is built of characteristic 2 nm wheel clusters with fivefold rotational symmetry, which agrees with results from high-resolution electron microscopy images. Simulated electron diffraction patterns for the structure model are in good agreement with the experimental electron diffraction patterns obtained by RED.

  • 11.
    Willhammar, Tom
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Burton, Allen W
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Yun, Yifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Afeworki, Mobae
    Strohmaier, Karl G
    Vroman, Hilda
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    EMM-23: A Stable High-Silica Multidimensional Zeolite with Extra-Large Trilobe-Shaped Channels.2014In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 136, no 39, p. 13570-3Article in journal (Refereed)
    Abstract [en]

    Stable, multidimensional, and extra-large pore zeolites are desirable by industry for catalysis and separation of bulky molecules. Here we report EMM-23, the first stable, three-dimensional extra-large pore aluminosilicate zeolite. The structure of EMM-23 was determined from submicron-sized crystals by combining electron crystallography, solid-state nuclear magnetic resonance (NMR), and powder X-ray diffraction. The framework contains highly unusual trilobe-shaped pores that are bound by 21-24 tetrahedral atoms. These extra-large pores are intersected perpendicularly by a two-dimensional 10-ring channel system. Unlike most ideal zeolite frameworks that have tetrahedral sites with four next-nearest tetrahedral neighbors (Q(4) species), this unusual zeolite possesses a high density of Q(2) and Q(3) silicon species. It is the first zeolite prepared directly with Q(2) species that are intrinsic to the framework. EMM-23 is stable after calcination at 540 °C. The formation of this highly interrupted structure is facilitated by the high density of extra framework positive charge introduced by the dicationic structure directing agent.

  • 12.
    Willhammar, Tom
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Yun, Yifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Burton, Allen
    Afeworki, Mobae
    Strohmaier, Karl G.
    Cheng, Jane
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    The first stable high silica zeolite with extra-large 24-ring channelsManuscript (preprint) (Other academic)
  • 13.
    Willhammar, Tom
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Yun, Yifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Structural Determination of Ordered Porous Solids by Electron Crystallography2014In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 24, no 2 (SI), p. 182-199Article, review/survey (Refereed)
    Abstract [en]

    Knowing the structure of porous materials is essential for understanding their properties and exploiting them for applications. Electron crystallography has two main advantages compared to X-ray diffraction for structure determination. Crystals too small or too complicated to be studied by X-ray diffraction can be studied by electron crystallography. The crystallographic structure factor phase information, which is lost in X-ray diffraction, can be obtained from high-resolution transmission electron microscopy (HRTEM) images. Here, different electron microscopic techniques and their applications for structure determination of porous materials are reviewed. The recently developed automated diffraction tomography (ADT), the rotation electron diffraction (RED), and the through-focus structure projection reconstruction (QFcous) methods make the structure determination by electron crystallography more feasible for non-TEM experts and as efficient as that by X-ray diffraction. How the various electron crystallographic methods are chosen are demonstrated and these methods used for solving different structural problems in porous materials. The benefits of combining electron crystallography and X-ray diffraction for studying complex zeolite structures are also shown. A large number of examples are given to demonstrate the use of various electron crystallographic techniques for structure determination of zeolites, metal-organic frameworks and ordered mesoporous materials. These electron crystallographic methods are general and can also be used for structural studies of other functional materials.

  • 14.
    Yao, Qingxia
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Bermejo Gómez, Antonio
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Su, Jie
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Pascanu, Vlad
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Yun, Yifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zheng, Haoquan
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Chen, Hong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Liu, Leifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Abdelhamid, Hani Nasser
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Martin-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Series of Highly Stable Isoreticular Lanthanide Metal-Organic Frameworks with Expanding Pore Size and Tunable Luminescent Properties2015In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 27, no 15, p. 5332-5339Article in journal (Refereed)
    Abstract [en]

    A series of highly porous isoreticular lanthanide-based metal organic frameworks (LnMOFs) denoted as SUMOE-7I to SUMOE-7IV (SU = Stockholm University; Ln = La, Ce, Pr, Nd, Sm, Eu, and Gd) have been synthesized using tritopic carboxylates as the organic linkers. The SUMOF-7 materials display one-dimensional pseudohexagonal channels with the pore diameter gradually enlarged from 8.4 to 23.9 angstrom, as a result of increasing sizes of the organic linkers. The structures have been solved by single crystal X-ray diffraction or rotation electron diffraction (RED) combined with powder X-ray diffraction (PXRD). The SUMOF-7 materials exhibit robust architectures with permanent porosity. More importantly, they exhibit exceptionally high thermal and chemical stability. We show that, by inclusion of organic dye molecules, the luminescence properties of the MOFs can be elaborated and modulated, leading to promising applications in sensing and optics.

  • 15.
    Yao, Qingxia
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Bermejo Gómez, Antonio
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Su, Jie
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Pascanu, Vlad
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Yun, Yifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zheng, Haoquan
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Chen, Hong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Liu, Leifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Highly porous isoreticular lanthanide metal-organic frameworksManuscript (preprint) (Other academic)
    Abstract [en]

    As an emerging type of porous materials, metal–organic frameworks (MOFs) have the advantages over conventional inorganic porous materials in that their structures and functions are systematically and predictably designable. Isoreticular expansion is an efficient way for systematic design and control of pore size and shape for MOFs. By using our proposed strategy, a series of highly porous isoreticular lanthanide-based metal-organic frameworks with systematic pore apertures has been obtained, which afford an isoreticular series of MIL-103 structures (termed SUMOF-7I to IV) with pore apertures ranging from 7.2 Å to 23 Å. These materials demonstrated exhibit robust architectures with permanent porosity, and exceptional thermal stability and chemical stability in various solvents. The combination of luminescence property and significant porosity of these MOFs enable them as a potential platform for multifunctional purpose.

  • 16.
    Yun, Yifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Characterization of crystalline materials by rotation electron diffraction: Phase identification and structure determination2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Electron crystallography is powerful for determination of complex structures. The newly-developed 3D electron diffraction (ED) methods make structure determination from nano- and micron-sized crystals much easier than using other methods, for example X-ray diffraction. Almost complete 3D ED data can be collected easily and fast from crystals at any arbitrary orientations. Dynamical effects are largely reduced compared to zonal ED patterns. 3D ED is powerful for phase identification and structure solution from individual nano- and micron-sized crystals, while powder X-ray diffraction (PXRD) provides information from all phases present in the samples. 3D ED methods and PXRD are complementary and their combinations are promising for studying multiphasic samples and complicated crystal structures.

    In this thesis, the feasibility and capability of 3D ED methods, specifically rotation electron diffraction (RED), in phase identification and structure determination of different kinds of crystalline materials with nano- or submicrometer-sized crystals are investigated. Experimental conditions for RED data collection and data processing in relation to data quality, as well as the challenges in the applications of RED are discussed.

    RED was combined with PXRD to identify phases from as-synthesized samples and to characterize atomic structures of eleven crystalline compounds. It was shown to be possible to identify as many as four distinct compounds within one sample containing submicron-sized crystals in a Ni-Se-O-Cl system. RED was also used to determine unit cell and symmetry of isoreticular metal-organic frameworks (SUMOF-7) and solve five zeolite structures with new frameworks, ITQ-51, ITQ-53, ITQ-54, EMM-23 and EMM-25 and that of a metal-organic framework (MOF), SUMOF-7I. The structure of an open-framework germanate SU-77 was solved by combining RED with PXRD. The structures of the zeolites and SU-77 were confirmed by Rietveld refinement against PXRD. High-resolution transmission electron microscopy was used to confirm the structure models of ITQ-51, EMM-25 and SUMOF-7I.

  • 17.
    Yun, Yifeng
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Hernandez, Manuel
    Wan, Wei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Jorda, Jose L.
    Cantin, Angel
    Rey, Fernando
    Corma, Avelino
    The first zeolite with a tri-directional extra-large 14-ring pore system derived using a phosphonium-based organic molecule2015In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 51, no 36, p. 7602-7605Article in journal (Refereed)
    Abstract [en]

    A new germanosilicate zeolite (denoted as ITQ-53) with extra-large pores has been synthesised using tri-tertbutylmethylphosphonium cation as the organic structure directing agent (OSDA). Rotation electron diffraction (RED) was used to identify ITQ-53 from an initially-synthesised sample containing impurities, and to solve its structure. The structure was refined against PXRD data of pure ITQ-53 samples obtained after synthesis optimisation. ITQ-53 is the first example of extra-large pore zeolites with tri-directional interconnected 14 x 14 x 14-ring channels. It is stable up to at least 650 degrees C. The structure of ITQ-53 changes from monoclinic to orthorhombic upon calcination.

  • 18.
    Yun, Yifeng
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Hernández, Manuel
    Wan, Wei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Jordá, Jose L.
    Cantín, Angel
    Rey, Fernando
    Corma, Avelino
    The first zeolite with a tri-directional extra-large 14-ring pore system derived using a phosphonium-based organic moleculeManuscript (preprint) (Other academic)
    Abstract [en]

    A new germanosilicate zeolite (denoted as ITQ-53) with extra-large 14-ring pores has been synthesized using tri-tertbutylmethylphosphonium cation as the organic structure directing agent (OSDA). The new rotation electron diffraction (RED) method was used to both identify and solve the structure of ITQ-53 from an initially synthesized sample containing impurities, which facilitated the synthesis optimization that led to pure ITQ-53. The structure was refined against PXRD data. ITQ-53 is the first example of extra-large pore zeolites with tri-directional interconnected 14 × 14 × 14-ring channels. It is built from double 3-rings (D3Rs), double 4-rings (D4Rs), and a new composite building unit [42.54.63]. D3Rs are very rare, previously only found in two zeolitic silicogermanates. ITQ-53 is stable up to at least 450 °C. The structure of ITQ-53 was changed from monoclinic to orthorhombic up on calcination.

  • 19.
    Yun, Yifeng
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Wan, Wei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Rabbani, Faiz
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Su, Jie
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Xu, Hongyi
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Hovmöller, Sven
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Johnsson, Mats
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Phase identification and structure determination from multiphase crystalline powder samples by rotation electron diffraction2014In: Journal of applied crystallography, ISSN 0021-8898, E-ISSN 1600-5767, Vol. 47, p. 2048-2054Article in journal (Refereed)
    Abstract [en]

    Phase identification and structure characterization are important in synthetic and materials science. It is difficult to characterize the individual phases from multiphase crystalline powder samples, especially if some of the phases are unknown. This problem can be solved by combining rotation electron diffraction (RED) and powder X-ray diffraction (PXRD). Four phases were identified on the same transmission electron microscopy grid from a multiphase sample in the Ni-Se-O-Cl system, and their structures were solved from the RED data. Phase 1 (NiSeO3) was found in the Inorganic Crystal Structure Database using the information from RED. Phase 2 (Ni3Se4O10Cl2) is an unknown compound, but it is isostructural to Co3Se4O10Cl2, which was recently solved by single-crystal X-ray diffraction. Phase 3 (Ni5Se6O16Cl4H2) and Phase 4 (Ni5Se4O12Cl2) are new compounds. The fact that there are at least four different compounds in the as-synthesized material explains why the phase identification and structure determination could not be done by PXRD alone. The RED method makes phase identification from such multiphase powder samples much easier than would be the case using powder X-ray diffraction. The RED method also makes structure determination of submicrometre-sized crystals from multiphase samples possible.

  • 20.
    Yun, Yifeng
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Wan, Wei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Rabbani, Faiz
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Su, Jie
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Xu, Hongyi
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Hovmöller, Sven
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Johnsson, Mats
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Phase identification and structure determination from multiphasic crystalline powder samples by rotation electron diffractionIn: Journal of applied crystallography, ISSN 0021-8898, E-ISSN 1600-5767Article in journal (Refereed)
    Abstract [en]

    Phase identification and structure characterisation are important in synthetic and material science. It is difficult to characterise the individual phases from multiphasic crystalline powder samples, especially if some of the phases are unknown. Here we describe how this problem can be solved by combining rotation electron diffraction (RED) and powder X-ray diffraction (PXRD). Four phases were identified on the same transmission electron microscopy (TEM) grid from a multiphasic sample in the Ni-Se-O-Cl system and their structures were solved from the RED data. Phase 1 (NiSeO3) was found in the Inorganic Crystal Structure Data (ICSD) database using the information from RED. Phase 2 (Ni3Se4O10Cl2) is an unknown compound but it is iso-structural to Co3Se4O10Cl2, which was recently solved by single crystal X-ray diffraction. Phase 3 (Ni5Se6O16Cl4H2) and Phase 4 (Ni5Se4O12Cl2) are new compounds. The fact that there are at least four different compounds in the as-synthesised material explains why the phase identification and structure determination could not be done only by PXRD. The RED method makes phase identification from such multiphasic powder samples much easier compared to powder X-ray diffraction. The RED method also makes structure determination of submicron-sized crystals from multiphasic samples possible.

  • 21.
    Yun, Yifeng
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Willhammar, Tom
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Wan, Wei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Burton, Allen
    Strohmaier, Karl G.
    Terefenko, Gene
    Vroman, Hilda
    Afeworki, Mobae
    Cheng, Jane
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Rational synthesis and structure of a borosilicate zeolite with intersecting 10- and 11-ring channelsManuscript (preprint) (Other academic)
  • 22.
    Yun, Yifeng
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Hovmöller, Sven
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Wan, Wei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Three-dimensional electron diffraction as a complementary technique to powder X-ray diffraction for phase identification and structure solution of powders2015In: IUCrJ, ISSN 2052-2525, Vol. 2, p. 267-282Article in journal (Refereed)
    Abstract [en]

    Phase identification and structure determination are important and widely used techniques in chemistry, physics and materials science. Recently, two methods for automated three-dimensional electron diffraction (ED) data collection, namely automated diffraction tomography (ADT) and rotation electron diffraction (RED), have been developed. Compared with X-ray diffraction (XRD) and two-dimensional zonal ED, three-dimensional ED methods have many advantages in identifying phases and determining unknown structures. Almost complete three-dimensional ED data can be collected using the ADT and RED methods. Since each ED pattern is usually measured off the zone axes by three-dimensional ED methods, dynamic effects are much reduced compared with zonal ED patterns. Data collection is easy and fast, and can start at any arbitrary orientation of the crystal, which facilitates automation. Threedimensional ED is a powerful technique for structure identification and structure solution from individual nano-or micron-sized particles, while powder X-ray diffraction (PXRD) provides information from all phases present in a sample. ED suffers from dynamic scattering, while PXRD data are kinematic. Three-dimensional ED methods and PXRD are complementary and their combinations are promising for studying multiphase samples and complicated crystal structures. Here, two three-dimensional ED methods, ADTand RED, are described. Examples are given of combinations of three-dimensional ED methods and PXRD for phase identification and structure determination over a large number of different materials, from Ni-Se-O-Cl crystals, zeolites, germanates, metal-organic frameworks and organic compounds to intermetallics with modulated structures. It is shown that three-dimensional ED is now as feasible as X-ray diffraction for phase identification and structure solution, but still needs further development in order to be as accurate as X-ray diffraction. It is expected that three-dimensional ED methods will become crucially important in the near future.

  • 23. Zhang, Yue-Biao
    et al.
    Su, Jie
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Furukawa, Hiroyasu
    Yun, Yifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Gandara, Felipe
    Duong, Adam
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Yaghi, Omar M.
    Single-Crystal Structure of a Covalent Organic Framework2013In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 135, no 44, p. 16336-16339Article in journal (Refereed)
    Abstract [en]

    The crystal structure of a new covalent organic framework, termed COF-320, is determined by single-crystal 3D electron diffraction using the rotation electron diffraction (RED) method for data collection. The COF crystals are prepared by an imine condensation of tetra-(4-anilyl)methane and 4,4'-biphenyldialdehyde in 1,4-dioxane at 120 degrees C to produce a highly porous 9-fold interwoven diamond net. COF-320 exhibits permanent porosity with a Langmuir surface area of 2400 m(2)/g and a methane total uptake of 15.0 wt % (176 cm(3)/cm(3)) at 25 degrees C and 80 bar. The successful determination of the structure of COF-320 directly from single-crystal samples is an important advance in the development of COF chemistry.

1 - 23 of 23
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf