Studying the structure of metal-organic polymers using in-house powder X-ray diffraction data: structural transformations induced by thermal treatment

Author(s):  
Antonia Neels ◽  
Yi Wang ◽  
Helen Stoeckli-Evans

AbstractThe use of X-ray powder diffraction for the structure determination of inorganic, organic and metal-organic compounds has grown impressively over the last ten years. In supramolecular chemistry, the knowledge of the three-dimensional structure of a material is essential for the discussion of its macroscopic behaviour, and as a result the design of new functionalized materials.TheThe reaction of pyrazine-2,5-dimethyl-3,6-dicarboxylic acid with first row transition metal salts lead to the formation of coordination polymers always in the form of microcrystalline powders. With manganese and nickel salts isostructural 1D coordination polymers were obtained. With zinc chloride and copper chloride isomorphous 1D coordination polymers were obtained. The thermal decomposition of the nickel and copper polymers were studied and it was shown that on the loss of the coordinated water molecules new 3D coordination polymers could be obtained. In both the 1D and 3D coordination polymers the metal atoms have octahedral geometry in N

2015 ◽  
Vol 68 (1) ◽  
pp. 121 ◽  
Author(s):  
Wenlong Liu ◽  
Xueying Wang ◽  
Mengqiang Wu ◽  
Bing Wang

Two new coordination polymers, namely, {[Cd3(bpt)2(bimb)2]·2(H2O)}n (1) and [Zn3(bpt)2(bimb)2]n (2) (bpt = biphenyl-3,4′,5-tricarboxylate, bimb = 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene), have been obtained under hydrothermal conditions. Their structures have been determined by single-crystal X-ray diffraction analysis and further characterised by elemental analysis and infrared spectroscopy. Complex 1 exhibits a trinodal (4,4,4)-connected topology with Schläfli symbol of (4.62.83)4.(64.82). Complex 2 is also a three-dimensional structure and displays a (3,4,6)-connected topology with Schläfli symbol of (4.62)2.(42.66.85.102).(64.82). It is shown that the asymmetrically tricarboxylate can bear diverse structures regulated by metal ions. The photoluminescence behaviours of compounds 1 and 2 were also discussed.


Author(s):  
Jian-Qing Tao

In the title mixed-ligand metal–organic polymeric complex [Cd(C14H8O6S)(C16H16N2)(H2O)]n, the asymmetric unit contains a crystallographically unique CdIIatom, one doubly deprotonated 4,4′-sulfonyldibenzoic acid ligand (H2SDBA), one 3,4,7,8-tetramethyl-1,10-phenanthroline (TMPHEN) molecule and one water molecule. Each CdIIcentre is coordinated by two N atoms from the chelating TMPHEN ligand, three O atoms from monodentate carboxylate groups of three different SDBA2−ligands and one O atom from a coordinated water molecule, giving a distorted CdN2O4octahedral geometry. Single-crystal X-ray diffraction analysis reveals that the compound is a one-dimensional double-chain polymer containing 28-membered rings based on Cd2O2clusters, with a Cd...Cd separation of 3.6889 (4) Å. These chains are linked by O—H...O and C—H...O hydrogen bonds to form a three-dimensional supramolecular framework. The framework is reinforced by π–π and C—O...π interactions.


Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 204
Author(s):  
Yu Li ◽  
Chumin Liang ◽  
Xunzhong Zou ◽  
Jinzhong Gu ◽  
Marina V. Kirillova ◽  
...  

Three 2D coordination polymers, [Cu2(µ4-dpa)(bipy)2(H2O)]n∙6nH2O (1), [Mn2(µ6-dpa)(bipy)2]n (2), and [Zn2(µ4-dpa)(bipy)2(H2O)2]n·2nH2O (3), were prepared by a hydrothermal method using metal(II) chloride salts, 3-(2′,4′-dicarboxylphenoxy)phthalic acid (H4dpa) as a linker, as well as 2,2′-bipyridine (bipy) as a crystallization mediator. Compounds 1–3 were obtained as crystalline solids and fully characterized. The structures of 1–3 were established by single-crystal X-ray diffraction, revealing 2D metal-organic networks of sql, 3,6L66, and hcb topological types. Thermal stability and catalytic behavior of 1–3 were also studied. In particular, zinc(II) coordination polymer 3 functions as a highly active and recoverable heterogeneous catalyst in the mild cyanosilylation of benzaldehydes with trimethylsilyl cyanide to give cyanohydrin derivatives. The influence of various parameters was investigated, including a time of reaction, a loading of catalyst and its recycling, an effect of solvent type, and a substrate scope. As a result, up to 93% product yields were attained in a catalyst recoverable and reusable system when exploring 4-nitrobenzaldehyde as a model substrate. This study contributes to widening the types of multifunctional polycarboxylic acid linkers for the design of novel coordination polymers with notable applications in heterogeneous catalysis.


2014 ◽  
Vol 919-921 ◽  
pp. 2013-2016 ◽  
Author(s):  
Ya Bing Liu ◽  
Hong Jie Wang ◽  
Hong Kai Zhao

A POM - based organice - inorganic hybrid compound with the chemical formula of[Cu (phen)2]3[W6O19] (phen = 1,10-phenanthroline) (1) has been hydrothermally synthesized andstructurally characterized by the elemental analysis, and single crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic space groupC2/c witha=18.319(4) Å,b= 17.311(4) Å,c= 22.248(4) Å,β= 112.40(3) o,V= 6523(2) Å3,Z= 4, R1= 0.0448, andwR2=0.1218. Compound 1 consists of the [W6O19]3-building blocks and [Cu (phen)2]+metal organic cationic moieties, which are packed together via the extensive hydrogen-bonding interactions to form a three-dimensional supramolecular framework. The adsorption of methylene blue (MB) under UV irradiation with 1 as the heterogeneous adsorbent has been investigated, showing a good adsorptive property of 1 for MB degradation.


2021 ◽  
Vol 9 ◽  
Author(s):  
Wang Xie ◽  
Jie Wu ◽  
Xiaochun Hang ◽  
Honghai Zhang ◽  
Kang shen ◽  
...  

By employment of amino-functionalized dicarboxylate ligands to react with d10 metal ions, four novel metal-organic frameworks (MOFs) were obtained with the formula of {[Cd(BCPAB)(μ2-H2O)]}n (1), {[Cd(BDAB)]∙2H2O∙DMF}n (2), {[Zn(BDAB)(BPD)0.5(H2O)]∙2H2O}n (3) and {[Zn(BDAB)(DBPB)0.5(H2O)]∙2H2O}n (4) (H2BCPAB = 2,5-bis(p-carbonylphenyl)-1-aminobenzene; H2BDAB = 1,2-diamino-3,6-bis(4-carboxyphenyl)benzene); BPD = (4,4′-bipyridine); DBPB = (E,E-2,5-dimethoxy-1,4-bis-[2-pyridin-vinyl]-benzene; DMF = N,N-dimethylformamide). Complex 1 is a three-dimensional (3D) framework bearing seh-3,5-Pbca nets with point symbol of {4.62}{4.67.82}. Complex 2 exhibits a 4,4-connected new topology that has never been reported before with point symbol of {42.84}. Complex 3 and 4 are quite similar in structure and both have 3D supramolecular frameworks formed by 6-fold and 8-fold interpenetrated 2D coordination layers. The structures of these complexes were characterized by single crystal X-ray diffraction (SC-XRD), thermal gravimetric analysis (TGA) and powder X-ray diffraction (PXRD) measurements. In addition, the fluorescence properties and the sensing capability of 2–4 were investigated as well and the results indicated that complex 2 could function as sensor for Cu2+ and complex 3 could detect Cu2+ and Ag+via quenching effect.


2006 ◽  
Vol 59 (9) ◽  
pp. 647 ◽  
Author(s):  
Yong-Tao Wang ◽  
Gui-Mei Tang ◽  
Da-Wei Qin

Three new inorganic–organic coordination polymers based on a versatile linking unit 2-(1H-imidazole-1-yl)acetate (Hima) and divalent Mn(ii), Ni(ii), and Cu(ii) ions, exhibiting two kinds of two dimensionalities with different topological structures, have been prepared in water medium and structurally characterized by single-crystal X-ray diffraction analysis. Reaction of MnCl2·4H2O and Ni(NO3)2·6H2O with Hima yielded neutral two-dimensional (2D) coordination polymers [M(ima)2]n, M = Mn(ii) 1, and Ni(ii) 2 with isostructural 2D coordination polymers possessing (3,6) topology structures, which further stack into three-dimensional (3D) supramolecular networks through C–H···O weak interactions. However, when Cu(NO3)2·4H2O was used, a neutral 2D coordination polymer [Cu(ima)2]n 3 consisting of rhombus units was generated, which showed a 3D supramolecular network through C–H···O weak interactions. Among these polymers, the building block ima anion exhibits different coordination modes. These results indicate that the versatile nature of this flexible ligand, together with the coordination preferences of the metal ions, plays a critical role in construction of these novel coordination polymers. Spectral and thermal properties of these new materials have also been investigated.


2011 ◽  
Vol 44 (3) ◽  
pp. 526-531 ◽  
Author(s):  
David Allen ◽  
Jochen Wittge ◽  
Jennifer Stopford ◽  
Andreas Danilewsky ◽  
Patrick McNally

In the semiconductor industry, wafer handling introduces micro-cracks at the wafer edge and the causal relationship of these cracks to wafer breakage is a difficult task. By way of understanding the wafer breakage process, a series of nano-indents were introduced both into 20 × 20 mm (100) wafer pieces and into whole wafers as a means of introducing controlled strain. Visualization of the three-dimensional structure of crystal defects has been demonstrated. The silicon samples were then treated by various thermal anneal processes to initiate the formation of dislocation loops around the indents. This article reports the three-dimensional X-ray diffraction imaging and visualization of the structure of these dislocations. A series of X-ray section topographs of both the indents and the dislocation loops were taken at the ANKA Synchrotron, Karlsruhe, Germany. The topographs were recorded on a CCD system combined with a high-resolution scintillator crystal and were measured by repeated cycles of exposure and sample translation along a direction perpendicular to the beam. The resulting images were then rendered into three dimensions utilizing open-source three-dimensional medical tomography algorithms that show the dislocation loops formed. Furthermore this technique allows for the production of a video (avi) file showing the rotation of the rendered topographs around any defined axis. The software also has the capability of splitting the image along a segmentation line and viewing the internal structure of the strain fields.


2019 ◽  
Vol 74 (6) ◽  
pp. 485-489
Author(s):  
Yuan Huang ◽  
Xiu-feng Yu ◽  
Zhen Rong ◽  
Yi-chun Ai ◽  
Kun Qian ◽  
...  

AbstractA new complex [Pr3NH]+ [Mn(dca)3]− · H2O (dicyanamide = dca−) was synthesized, in which the Mn2+ cations are bridged by end-to-end dca anions to form three-dimensional [Mn(dca)3]nn− networks and tripropylammonium cations reside in the cavities of these networks. The complex has been characterized by single-crystal X-ray diffraction, infrared spectroscopy, elemental analysis, and magnetic measurements. Magnetic susceptibility data indicate ferromagnetic interactions among the MnII ions.


1998 ◽  
Vol 333 (3) ◽  
pp. 811-816 ◽  
Author(s):  
Antonio PÁRRAGA ◽  
Isabel GARCÍA-SÁEZ ◽  
Sinead B. WALSH ◽  
Timothy J. MANTLE ◽  
Miquel COLL

The structure of mouse liver glutathione S-transferase P1-1 complexed with its substrate glutathione (GSH) has been determined by X-ray diffraction analysis. No conformational changes in the glutathione moiety or in the protein, other than small adjustments of some side chains, are observed when compared with glutathione adduct complexes. Our structure confirms that the role of Tyr-7 is to stabilize the thiolate by hydrogen bonding and to position it in the right orientation. A comparison of the enzyme–GSH structure reported here with previously described structures reveals rearrangements in a well-defined network of water molecules in the active site. One of these water molecules (W0), identified in the unliganded enzyme (carboxymethylated at Cys-47), is displaced by the binding of GSH, and a further water molecule (W4) is displaced following the binding of the electrophilic substrate and the formation of the glutathione conjugate. The possibility that one of these water molecules participates in the proton abstraction from the glutathione thiol is discussed.


2020 ◽  
pp. 174751982096816
Author(s):  
Fang-Kuo Wang ◽  
Shi-Yao Yang ◽  
Hua-Ze Dong

Two coordination polymers with two-dimensional and three-dimensional structures are, {[Zn3(bdc)3(py)2]·2NMP}n (1) (H2bdc = 1,4-benzenedicarboxylic acid) and [Zn2(NO3−)(btc)(nmp)2(py)]n (2) (H3btc = 1,3,5-benzenetricarboxylic acid), synthesized by hot-solution reactions of Zn(NO3)2·6H2O, pyridine (py) and two different ligands in N-methylpyrrolidone (NMP). {[Zn3(bdc)3(py)2]·2NMP}n exhibits two-dimensional networks with trizinc subunits [Zn3(COO)6py2] stacking with a layer-by-layer alignment, and there are strong π–π interactions involving py from adjacent layers. [Zn2(NO3−)(btc)(nmp)2(py)]n has a three-dimensional structure containing two independent zinc ions, tetrahedral ZnO4 and octahedral ZnNO5. Based on X-ray studies, the coordination polymers {[Zn3(bdc)3(py)2]·2NMP}n (1) have a porous structure with NMP guest molecules. In contrast, X-ray studies revealed that coordination polymer [Zn2(NO3−)(btc)(nmp)2(py)]n (2) had a larger void that was inhabited by coordinated py and NMP. In addition, the form of the two coordination polymers changed from two-dimensional to three-dimensional with transformation of the ligand geometry.


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