| 1. |
- Albat, Martin, et al.
(författare)
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Synthesis and crystal structure of three new bismuth(III) arylsulfonatocarboxylates
- 2017
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Ingår i: Zeitschrift für Kristallographie - Crystalline Materials. - : Walter de Gruyter GmbH. - 2194-4946 .- 2196-7105. ; 232:1-3, s. 245-253
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Tidskriftsartikel (refereegranskat)abstract
- Three new bismuth arylsulfonatocarboxylates [Bi(OH)(SB)] (1), [Bi-4(ST)(2)(HST)O-2(H2O)(2)]center dot H2O (2) and [Bi-4(ST)(2)O-3(H2O)(2)] (3) were synthesized under solvothermal reaction conditions at 180 degrees C using the potassium or sodium salt of 4-sulfobenzoic acid (H2SB) and 2-sulfoterephthalic acid (H3ST), respectively. The compounds were characterized in detail and the crystal structures were determined from single crystal X-ray diffraction data. Phase purity was confirmed by powder X-ray diffraction and elemental analysis. Structural comparisons to the only three other known bismuth sulfonatocarboxylates are presented. Due to the higher reaction temperatures employed for the synthesis of the title compounds a higher degree of condensation of the BiOx polyhedra (X = 7 or 8) to tetrameric units, 1D chains or a 2D layer is observed. Connection through the organic linker molecules leads to the formation of 3D coordination polymers in all three title compounds.
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| 2. |
- Carlson, Stefan, et al.
(författare)
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On the structure of Na5Mn3F14
- 1995
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Ingår i: Zeitschrift für Kristallographie. - : Walter de Gruyter GmbH. - 0044-2968. ; 210, s. 489-493
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Tidskriftsartikel (refereegranskat)abstract
- The crystal structure of the sodium manganese(III) fluoride compound, Na5Mn3F14, has been reinvestigated. The previous structure model, assuming the non-centrosymmetric space group symmetryPna21, has been transformed to the centrosymmetric symmetryPnam. Least squares refinements, based on new collected single crystal X-ray diffraction data, converged smoothly with the new structural model and yielded anR-value of 0.022. The general structural features described earlier, as the structural relations to the chiolite structure, still applies. However, the changed space group symmetry introduces new symmetry constraints to e.g. some of the coordination polyhedra in the structure.
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| 3. |
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| 4. |
- Gavryushkin, Pavel N., et al.
(författare)
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Temperature induced twinning in aragonite : transmission electron microscopy experiments and ab initio calculations
- 2019
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Ingår i: ZEITSCHRIFT FUR KRISTALLOGRAPHIE-CRYSTALLINE MATERIALS. - : WALTER DE GRUYTER GMBH. - 2194-4946 .- 2196-7105. ; 234:2, s. 79-84
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Tidskriftsartikel (refereegranskat)abstract
- The microstructure of aragonite, one of the main bio-mineral and component of bio-inspired materials, was described in numerous investigations. Using transmission electron microscopy (TEM), for the first time we show the effect of temperature on aragonite microstructure. The local increase of (0.5 0.5 0) reflections intensities and appearance of satellite reflections in [1 (1) over bar0] zone axis were observed above 350 degrees C. We explain the appearance of satellite reflections by the generation and ordering of {110} twin boundaries and suggest new thermal mechanism of the twin boundaries generation. We check the viability of this mechanism by ab initio molecular dynamics (AIMD) simulations and generalized solid state nudge elastic band (g-SSNEB) calculations.
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| 5. |
- Guo, Peng, et al.
(författare)
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On the relationship between unit cells and channel systems in high silica zeolites with the butterfly projection
- 2015
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Ingår i: Zeitschrift für Kristallographie - Crystalline Materials. - : Walter de Gruyter GmbH. - 2194-4946 .- 2196-7105. ; 230:5, s. 301-309
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Tidskriftsartikel (refereegranskat)abstract
- Zeolites are crystalline aluminosilicate framework materials with corner sharing TO 4 (T = Al, Si) tetrahedra forming well-defined pores and channels. Many zeolites are built from similar building units (i.e., isolated units, chains or layers), which are connected in different ways to form a variety of topologies. We have identified ten zeolite frameworks that share the same two-dimensional butterfly net containing 5-, 6- and 10-rings: (MRE)-M-star, FER, MEL, SZR, MFS, MFI, TUN, IMF, BOG and TON. Different orientations of the TO4 tetrahedra within the layer lead to different connectivities between neighboring layers. Some layers are corrugated and some are flat, resulting in different channel systems parallel to the layer. We found some interesting relationships between the unit cell parameters and this channel system that allow the size of the channels and their directions to be deduced from the unit cell dimensions. This may facilitate the prediction of new members of this zeolite family. In addition, other zeolites containing the butterfly layers are also discussed.
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| 6. |
- Karmakar, Anirban, 1983, et al.
(författare)
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Synthesis, structure and thermal study of a new 3-aminopyrazine-2-carboxylate based zinc(II) coordination polymer
- 2015
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Ingår i: Zeitschrift fur Kristallographie - Crystalline Materials. - : Walter de Gruyter GmbH. - 2196-7105 .- 2194-4946. ; 230:6, s. 413-419
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Tidskriftsartikel (refereegranskat)abstract
- A two-dimensional coordination polymer [Zn(L)(2)](n) (1) (L = 3-aminopyrazine-2-carboxylate) synthesized from the solvothermal reaction of zinc(II) salt with 3-aminopyrazine-2-carboxylic acid (HL) is described. Compound 1 has been characterized by single X-ray diffraction, IR spectra and thermogravimetric analyses. Crystal structure analysis reveals that each hexacoordinated zinc(II) center adopts a distorted octahedral geometry occupied by three O-carboxylate and three N-pyrazine atoms. The L-ligand binds the metal cation by means of a pyrazine N-atom and one, or both, carboxylate O-atoms. A three-dimensional supramolecular associate in the crystal lattice of 1 has been stabilized by a number of non-covalent interactions. The IR spectroscopic and TGA properties are investigated in this work. Topological analysis of the two-dimensional network has been also discussed.
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| 7. |
- Karpus, Vytautas, et al.
(författare)
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Optical response of si-ZnMgHo quasicrystal
- 2009
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Ingår i: ZEITSCHRIFT FUR KRISTALLOGRAPHIE. - : Walter de Gruyter GmbH. - 0044-2968. ; 224:1-2, s. 39-41
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Tidskriftsartikel (refereegranskat)abstract
- The results of room-temperature optical study of single-grain simple icosahedral ZnMgHo quasicrystals are presented. The dielectric function epsilon(omega) of the quasicrystals was measured by spectroscopic ellipsometry technique in the spectral range of 0.1 - 7 eV. The si-ZnMgHo optical response is a superposition of the free-electron Drude-type contribution and that of the interband transitions. The experimental epsilon(omega) spectra are well simulated within a framework of the band structure hypothesis. The deduced parameters of the si-ZnMgHo electron energy spectrum are close to their values determined previously in an analysis of the si-ZnMgHo photoemission data.
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| 8. |
- Langer, Vratislav, 1949, et al.
(författare)
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Crystal and electronic structure of aqua(N-salicylidene-methylester-L-glutamato)Cu(II) monohydrate
- 2004
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Ingår i: Zeitschfrift für Kristallographie. - : Walter de Gruyter GmbH. - 0044-2968. ; 219:2, s. 112-116
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Tidskriftsartikel (refereegranskat)abstract
- The absolute structure of the title compound, CuNC13H17O7, has been determined. The crystal structure consists of the molecular units Cu(N-sal-5-met-L-glu)(H2O) connected by a three-dimensional network of hydrogen bonds. The coordination polyhedron in the complex is approximately square-pyramidal with a pentacoordinated Cu(II) atom. The base of the pyramid is formed by nitrogen and oxygen atoms belonging to the molecule, while the apex of the pyramid contains a weakly bonded oxygen atom of the carboxylic group of another molecule. The B3LYP/SVP method and basis set in Gaussian98 was used for quantum chemical calculation of the nature of CuX (X = O, N) bonds. While the calculated dissociation energy of the weakly bonded crystalline water is only 17.2 kJ/mol, the bonding energy of the water molecule coordinating to the Cu atom is 62.3 kJ/mol.
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| 9. |
- Mohammadnezhad, G., et al.
(författare)
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Formation of R-4(4) (8) ring in chloride salts of 8-hydroxyquinolinium derivatives: synthesis, structural, and theoretical studies
- 2015
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Ingår i: Zeitschrift Fur Kristallographie-Crystalline Materials. - : Walter de Gruyter GmbH. - 2194-4946 .- 2196-7105. ; 230:3, s. 157-165
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Tidskriftsartikel (refereegranskat)abstract
- The molecular structures of chloride salts of 2and 5- substituted derivatives of 8- hydroxyquinoline, MeH 2 Q+ u Cl- ([ C 10 H 10 NO] Cl) and Cl- H 2 Q+ u Cl- ([ C 9 H 7 ClNO]+ u Cl-), were determined by single crystal X- ray diffraction methods; the latter is a new polymorph. In the crystal structures of these salts, several intra- and inter- molecular interactions result in a step- shaped centrosymmetric 4 4 R ( 8) ring. Unlike most quinolinium salts, there was no solvent present in these structures. Protonation of the quinoline N atom had an effect on the N uuu O bite distances and C- N- C angle and greater conjugation of the benzene ring with a hydroxyl group was also observed. p- p Interactions between each pair of quinolinium rings were observed in Me- H 2 Q+ u Clbut not in Cl- H 2 Q+ u Cl-. In addition, the quantum chemical calculations were performed on the new structures as well as similar compounds for comparison. The optimized structures were compared with the experimental observations for the effect of protonation and of hydrogen bonding interactions.
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| 10. |
- Piątek, Jędrzej, 1993-, et al.
(författare)
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Organic-inorganic interface chemistry for sustainable materials
- 2023
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Ingår i: Zeitschrift für Kristallographie - Crystalline Materials. - : Walter de Gruyter GmbH. - 2196-7105 .- 2194-4946. ; 238:3-4, s. 73-85
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Forskningsöversikt (refereegranskat)abstract
- This mini-review focuses on up-to-date advances of hybrid materials consisting of organic and inorganic components and their applications in different chemical processes. The purpose of forming such hybrids is mainly to functionalize and stabilize inorganic supports by attaching an organic linker to enhance their performance towards a target application. The interface chemistry is present with the emphasis on the sustainability of their components, chemical changes in substrates during synthesis, improvements of their physical and chemical properties, and, finally, their implementation. The latter is the main sectioning feature of this review, while we present the most prosperous applications ranging from catalysis, through water purification and energy storage. Emphasis was given to materials that can be classified as green to the best in our consideration. As the summary, the current situation on developing hybrid materials as well as directions towards sustainable future using organic-inorganic hybrids are presented.
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| 11. |
- Ptasiewicz-Bak, H., et al.
(författare)
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Location of the proton in the very strong OHO hydrogen bonds in 2-(N,N-diethylamino-N-oxymethyl)-4,6-dichlorophenol. A single crystal neutron diffraction study
- 1997
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Ingår i: Zeitschrift für Kristallographie. New crystal structures. - : Walter de Gruyter GmbH. - 1433-7266 .- 2197-4578. ; 212:2, s. 126-129
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Tidskriftsartikel (refereegranskat)abstract
- The crystal structure of 2-(N,N-diethylamino-N-oxymethyl)-4,6-dichlorophenol contains two slightly different molecules A and B, both with very strong intramolecular O … H … O hydrogen bonds, with O–O distances 2.423(4) Å and 2.400(5) Å, respectively, and with no crystallographic symmetry. The bridging oxygen atoms are also chemically different, O1 is bonded to carbon and O2 to nitrogen. The single crystal neutron diffraction study shows quite unambiguously that the proton in both cases is located slightly off-centred. In the A molecule O1–H = 1.167(6) Å, H–O2 = 1.258(6) Å and the angle O–H–O = 175.8(5)°; in the B molecule O1–H = 1.186(7) Å, H–O2 = 1.214(7) Å and the angle O–H–O = 176.5(5)°. As expected the proton is thus closer to the centre in the slightly shorter hydrogen bond.
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| 12. |
- Richter, Kai, et al.
(författare)
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Elucidating structure-property relationships in imidazolium-based halide ionic liquids : crystal structures and thermal behavior
- 2020
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Ingår i: Zeitschrift für Kristallographie - Crystalline Materials. - : Walter de Gruyter GmbH. - 2194-4946 .- 2196-7105. ; 235:8-9, s. 365-374
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Tidskriftsartikel (refereegranskat)abstract
- A set of imidazolium-based ionic liquids (ILs), 1-(2-hydroxyethyl)-3-methylimidazolium chloride (1), 1,3-bis-(2-hydroxyethyl)-imidazolium chloride (2), and 1-butyl-2,3,4,5-tetramethylimidazolium bromide (3), has been synthesized and their structural and thermal behavior studied. Organic halides are well-known IL formers with imidazolium halides being the most prominent ones. Functionalization of the imidazolium cation by enhancing its hydrogen bonding capacity, i.e. through introduction of -OH groups or by diminishing it, i.e. through substitution of the ring hydrogen atoms by methyl groups is expected to change the inter-ionic interactions. Consequently, the solid-state structures of 1-3 have been characterized with means of single X-ray diffraction to shed light on preferential inter-ionic interactions for obtaining valuable information on anti-crystal engineering, i.e. designing ion combinations that favor a low melting point and exhibit a low tendency for crystallization. The study reveals that endowing IL forming ions with an enhanced hydrogen bonding capacity leads to a depression in melting points and kinetically hinders crystallization. This study provides hints towards new design concepts for IL design, similar to the common strategy of employing conformationally flexible ions.
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| 13. |
- Smrcok, Lubomir, et al.
(författare)
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Intramolecular hydrogen bond and proton transfer in 3-(2-benzimidazolylthio)-2,4-pentanedione. Crystallographic evidence and theoretical calculations
- 2002
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Ingår i: Zeitschfrift für Kristallographie. - : Walter de Gruyter GmbH. - 0044-2968. ; 217:5, s. 217-222
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Tidskriftsartikel (refereegranskat)abstract
- Crystal structure of the title compound is orthorhombic, Pbca, a=7.8689(2)Å, b=9.6519(3)Å, c=31.3579(9)Å. The structure was solved by direct methods and refined by a full-matrix least squares procedure to final R (all)=0.0682 for 2853 unique diffractions merged from 24459 measured at 183(2)K. The molecule is formed by two planar moieties joined through an atom of sulphur. The short intramolecular O...O contact is 2.430(2)Å, the intramolecular hydrogen bond is slightly asymmetric. Theoretical ab initio calculations done at B3LYP/SVP and ONIOM(MP2/SVP:B3LYP/SVP) levels showed that the experimental geometry of pentanedione pseudoring is close to the geometry corresponding to a transition state on the asymmetric potential energy curve. Calculated energy difference between two minima is only 4.72 kJ/mol and the energy barrier 6.02 kJ/mol, which agrees well to ~6.6kJ/mol found in microwave spectroscopic study of malonaldehyde.
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| 14. |
- Strand, Daniel, et al.
(författare)
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Allotwinning and OD-structures-the example of malonamide
- 2016
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Ingår i: Zeitschrift fur Kristallographie - Crystalline Materials. - : Walter de Gruyter GmbH. - 2194-4946 .- 2196-7105. ; 231:10, s. 623-629
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Tidskriftsartikel (refereegranskat)abstract
- Allotwinning, the ordered intergrowth of two different structures may often be seen as a special case of OD-structures. The same structural ambiguity that allows for locally identical but globally different components of an allotwin may also allow the formation of an OD structure. When this is the case, the components of the allotwin often correspond to the MDO-structures of OD theory. Starting from the example of malonamide, we observe that any structure with z′=2 and a pronounced pseudo symmetry is a candidate for allotwinning and/or OD-structuring.
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| 15. |
- Yamada, Tsunetomo, et al.
(författare)
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In-situ high-pressure X-ray diffraction on the Zn6Sc 1/1 periodic cubic approximant to a quasicrystal
- 2014
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Ingår i: Zeitschrift fur Kristallographie. - : Walter de Gruyter GmbH. - 0044-2968. ; 229:3, s. 230-235
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Tidskriftsartikel (refereegranskat)abstract
- The Zn6Sc 1/1 cubic approximant to a quasicrystal has been studied in-situ at high pressures by single-crystal X-ray diffraction. This phase can be described as a bcc packing of Tsai-type icosahedral clusters whose center is occupied by a disordered Zn-4 tetrahedron. At ambient pressure the Zn6Sc undergoes a structural phase transition at 159 K to a monoclinic superstructure in which the Zn-4 tetrahedra are orientationally ordered along the [101] direction of the high-temperature bcc phase. In the pressure range up to 35 GPa, two new superstructures have been observed. The second phase corresponds to a four-fold pseudo cubic superstructure, i.e. a very large unit cell with a lattice parameter of about 5.5 nm. The resulting pressure-temperature phase diagram is different from that of Cd6Yb, which was reported by Watanuki et al. (2006).
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| 16. |
- Johannesson, Louise, et al.
(författare)
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Basic language learning in artificial animals
- 2019
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Ingår i: Advances in Intelligent Systems and Computing. - Cham : Springer International Publishing. - 2194-5365 .- 2194-5357. - 9783319993157 ; , s. 155-161
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Konferensbidrag (refereegranskat)abstract
- We explore a general architecture for artificial animals, or animats, that develops over time. The architecture combines reinforcement learning, dynamic concept formation, and homeostatic decision-making aimed at need satisfaction. We show that this architecture, which contains no ad hoc features for language processing, is capable of basic language learning of three kinds: (i) learning to reproduce phonemes that are perceived in the environment via motor babbling; (ii) learning to reproduce sequences of phonemes corresponding to spoken words perceived in the environment; and (iii) learning to ground the semantics of spoken words in sensory experience by associating spoken words (e.g. the word “cold”) to sensory experience (e.g. the activity of a sensor for cold temperature) and vice versa.
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| 17. |
- Gemmi, Mauro, et al.
(författare)
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Scanning reciprocal space for solving unknown structures : energy filtered diffraction tomography and rotation diffraction tomography methods
- 2013
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Ingår i: Zeitschrift fur Kristallographie. - : Walter de Gruyter GmbH. - 0044-2968. ; 228:1, s. 51-58
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Tidskriftsartikel (refereegranskat)abstract
- Structure solutions of CaFe2O4 from energy filtered and unfiltered precession electron diffraction tomography and rotation electron diffraction tomography data, collected on two different microscopes, are reported. The collected data are analysed with three available software packages (ADT3D, PETS and EDT-PROCESS) and the obtained results are compared. In all cases the structure solution is successfully achieved. Energy filtered precession electron diffraction tomography, performed here for the first time, gives sharper diffraction peaks and less background compared to the unfiltered data and the final recovered model is closer to the X-ray refinement. Simultaneously the first crystal structure solution obtained from the rotation electron diffraction tomography data is reported.
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| 18. |
- Karmakar, Anirban, 1983, et al.
(författare)
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A two-dimensional metal organic network with 1,3,5-benzenetricarboxylate and cobalt (II) ions: synthesis, structure and topology
- 2013
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Ingår i: Zeitschfrift für Kristallographie. - : Walter de Gruyter GmbH. - 0044-2968. ; 228:7, s. 330-334
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Tidskriftsartikel (refereegranskat)abstract
- We herein report the synthesis and structure of a two dimensional (2D) metal-organic coordination polymer (or metal-organic network) which extends in two dimensions via Co2+ and 1,3,5-benzenetricarboxylate ions. The hydrothermal reaction of (2R,2'R,2 '' R)-2,2',2 ''-(benzenetricarbonyltris(azanediyl))tripropanoic acid (parent ligand) with cobalt nitrate in the presence of pyridine lead to the decomposition of the parent ligand producing 1,3,5-benzenetricarboxylate, which in turn reacted with cobalt ions to afford a 2D network [Co-1.5(BTC3-) center dot (pyridine)(3) center dot (H2O)](H2O)(0.26) center dot (MeOH) (1). This network was characterized by single crystal X-ray diffraction and IR spectroscopy. The topological study indicated that the framework is a 3,4-connected binodal net.
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| 19. |
- Klingstedt, Miia, et al.
(författare)
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Exit wave reconstruction from focal series of hrtem images, single crystal xrd and total energy studies on sbxwo3+y (x similar to 0.11)
- 2012
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Ingår i: Zeitschrift fur Kristallographie. - : Walter de Gruyter GmbH. - 0044-2968 .- 2194-4946. ; 227:6, s. 341-349
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Tidskriftsartikel (refereegranskat)abstract
- A new tungsten bronze in the Sb-W-O system has been prepared in a solid state reaction from Sb2O3, WO3 and W metal powder. The average structure was determined by single crystal X-ray diffraction. SbxWO3+y (x similar to 0.11) crystallizes in the orthorhombic space group Pm2(1)n (no. 31), a = 27.8135(9) angstrom, b = 7.3659(2) angstrom and c = 3.8672(1) angstrom. The structure belongs to the (n)-ITB class of intergrowth tungsten bronzes. It contains slabs of hexagonal channels formed by six WO6 octahedra. These slabs are separated by three layers of WO6 octahedra that are arranged in a WO3-type fashion. The WO6 octahedra share all vertices to build up a three-dimensional framework. The hexagonal channels are filled with Sb atoms to similar to 80% and additional 0 atoms. The atoms are shifted out of the center of the channels. Exit-wave reconstruction of focal series of high resolution-transmission-electron-microscope (HRTEM) images combined with statistical parameter estimation techniques allowed to study local ordering in the channels. Sb atoms in neighbouring channels tend to be displaced in the same direction, which is in agreement with total energy calculations on ordered structure models, but the ratio of the occupation of the two possible Sb sites varies from channel to channel. The structure of SbxWO3+y exhibits pronounced local modulations.
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| 20. |
- Lundberg, Daniel, et al.
(författare)
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On the coordination chemistry of the dimercury(I) ion with O-donor ligands
- 2012
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Ingår i: Zeitschrift für Kristallographie. - : Walter de Gruyter GmbH. - 0044-2968. ; 227, s. 683-687
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Tidskriftsartikel (refereegranskat)abstract
- An overview of published crystalline dimercury(I) hydrates, solvates, and complexes/compounds with other O-donor ligands shows that there is virtually no correlation between the Hg-Hg bond distance and the overall Hg-O bonding conditions. Additionally, many structures feature a different Hg-O bonding situation for the different halves of the dimercury(I) ion, Hg22+. To supplement these findings, the crystal structures of the perchlorate salts of hydrated and dimethylsulfoxide (dmso) solvated mercury(I), [Hg2(H2O)2](ClO4)2 (1) and [Hg10(OS(CH3)2)16](ClO4)10 (2), respectively, have been determined by single crystal X-ray diffraction. In compound 1, the perchlorate ions act as bridges between the almost linear [Hg2(H2O)2]2+ units forming infinite chains. The Hg-Hg bond distance is 2.500(1) Å and the Hg-O distance to the water molecule is 2.231(19) Å, and with six additional much weaker Hg-O bonds to bridging perchlorate oxygens in the range 2.78-3.15 Å. Compound 2 consists of five separate entities where the [Hg-Hg]2+ units are solvated and bridged by dmso oxygens. These entities form chains through much weaker bridging perchlorate ions at longer distances, 3.0-3.3 Å, with a few remaining perchlorate ions isolated in the lattice. The mean Hg-Hg bond distance is 2.500(1) Å, while the Hg-Odmso bond distances are in the range of 2.15-2.92 Å. The dmso molecules display three kinds of coordination, strong κO-terminal, medium μ2O-bridging, or medium + weak μ3O-bridging, depending on which mercury(I) ion(s) in the entity they coordinate to.
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| 21. |
- Nimmermark, Anders, 1971, et al.
(författare)
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Metal-ligand bond lengths and strengths: are they correlated? A detailed CSD analysis
- 2013
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Ingår i: Zeitschfrift für Kristallographie. - : Walter de Gruyter GmbH. - 0044-2968. ; 228:7, s. 311-317
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Konferensbidrag (refereegranskat)abstract
- Structure data on metal-alkoxides, metal-alcohol, metal-carboxylates, metal-carboxylic acid, metal-azolate and metal-azole coordination compounds from the Cambridge Structural Database (CSD) were analysed in terms of bond lengths. In general the anionic ligands form shorter metal-ligand bonds by about 0.02-0.05 angstrom compared to neutral ligands, a clear indication of a charge contribution to the bonding interactions. This small difference is not, however, deemed as sufficient to generate two distinct classes of metal-ligand bonding. Instead, the anionic ligands can be viewed as having "charge assisted" metal-ligand bonding, corresponding to the same term used for "charge-assisted hydrogen bonding".
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| 22. |
- Willhammar, Tom, et al.
(författare)
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Stacking disorders in zeolites and open-frameworks - structure elucidation and analysis by electron crystallography and X-ray diffraction
- 2013
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Ingår i: Zeitschrift fur Kristallographie. - : Walter de Gruyter GmbH. - 0044-2968. ; 228:1, s. 11-27
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Forskningsöversikt (refereegranskat)abstract
- Intergrowth and stacking disorders are often found in minerals and synthetic zeolites and inorganic open-frameworks. Structure elucidation of stacking disorders in these materials have been difficult and structure solution of stacking disorders in unknown zeolites and open-frameworks has been challenging. There exist no standard methods for structure analysis of such disordered materials. In this review we present various stacking disorders and intergrowth in a number of representative zeolite families containing stacking disorders. These include zeolite beta, SSZ-26/SSZ-33, ITQ-39, ABC-6, ZSM-48, SSZ-31, UTD-1, faujasite FAU/EMT, pentasil ZSM-5/ZSM-11, ITQ-13/ITQ-34, ITQ-22/ITQ-38 etc. Stacking disorders in open-frameworks containing mixed coordinations, including titanosilicates ETS-10 and ETS-4, and the silicogermanate SU-JU-14 are also described. Various crystallographic methods used for solving disordered structures are summarized. The methods include powder X-ray diffraction (PXRD), electron diffraction, high resolution transmission electron microscopy (HRTEM), and single-crystal X-ray diffraction. Examples of model building combined with simulations of PXRD and single crystal X-ray diffraction to verify the structure models are given.
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| 23. |
- Yao, Qingxia, et al.
(författare)
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SUMOF-5 : a mesoporous metal-organic framework with the tbo topology built from the dicopper paddle-wheel cluster and a new tritopic linker
- 2013
-
Ingår i: Zeitschrift fur Kristallographie. - : Walter de Gruyter GmbH. - 0044-2968. ; 228:7, s. 323-329
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Tidskriftsartikel (refereegranskat)abstract
- A mesoporous metal-organic framework Cu-3(PTB)(2)(H2O)(3) center dot guest (denoted as SUMOF-5) has been synthesized using a new tritopic linker pyridine-2,4,6-tribenzoic acid (H3PTB). SUMOF-5 is cubic with the space group Fm (3) over barm and a = 47.272(3) angstrom. The framework is built of the dicopper paddle-wheel secondary building unit (SBU) [Cu-2(OOC)(4)(H2O)(2)] and contains two different cavities of 1.22 and 2.33 nm in diameter, respectively. The framework topology follows the (3,4)-connected tbo net, and can be regarded as an extended version of Cu-3(BTC)(2)(H2O)(3) center dot guest (HKUST-1, BTC = benzene tricarboxylate). The structure of SUMOF-5 is compared to other MOFs built from dicopper paddle-wheels and tritopic linkers. SUMOF-5 has permanent porosity with a Langmuir surface area of 1733 m(2)/g and is stable in various organic solvents, which makes this material potentially useful as a crystalline carrier for loading molecular catalysts or drugs.
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| 24. |
- Öhrström, Lars, 1963, et al.
(författare)
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Network topology approach to new allotropes of the group 14 elements
- 2013
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Ingår i: Zeitschfrift für Kristallographie. - : Walter de Gruyter GmbH. - 0044-2968. ; 228:7, s. 343-346
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Tidskriftsartikel (refereegranskat)abstract
- The network topology approach has been a major driving force in the search for new metal-organic frameworks and coordination networks. In this work we demonstrate how this method not only generated the recently described "T12" allotrope of the group 14 elements, identical to the cdp topology found in the structure of CdP2, but also a number of other candidate structures for polymorphs of these network-forming elements. Data on such network structures have been compiled since the 1950's and is readily accessible through several internet based systems. The usefulness of topology for the classification of these allotropes is emphasised.
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