Robust Microporous Molecular Frameworks Which Retain Structural Integrity Upon Template Loss

1998 ◽  
Vol 547 ◽  
Author(s):  
C. J. Kepert ◽  
M. J. Rosseinsky ◽  
D. Hesek ◽  
P. D. Beer
Keyword(s):  
Hydrogen Bonding ◽  
Molecular Modelling ◽  
Structural Integrity ◽  
Stacking Interactions ◽  
Void Space ◽  
X Ray Diffraction ◽  
X Ray ◽  
Donor And Acceptor ◽  
Modelling Techniques ◽  
Symmetry Change

AbstractRetention of the void space upon loss of the solvent template is directly demonstrated using single-crystal X-ray diffraction for molecular frameworks constructed using both hydrogen and co-ordinate bonds. While the co-ordination polymer remains rigid upon desolvation, the extra flexibility in the hydrogen-bonded framework, due both to the large number of redundant hydrogen-bonding donor and acceptor groups and the possibility of significant φ-φ stacking interactions within the framework, lead to a significant structural and symmetry change while retaining significant void volume. Molecular modelling techniques are used to understand and predict the guest uptake chemistry of these host frameworks.

2D X-ray diffraction and molecular modelling of the crystalline structure of polyesters under uniaxial stress

2021 ◽  
pp. 096739112199822
Author(s):  
Ahmed I Abou-Kandil ◽  
Gerhard Goldbeck
Keyword(s):  
Crystalline Structure ◽  
Molecular Modelling ◽  
Three Dimensional ◽  
Uniaxial Stress ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Modelling Techniques ◽  
Diffraction Patterns

Studying the crystalline structure of uniaxially and biaxially drawn polyesters is of great importance due to their wide range of applications. In this study, we shed some light on the behaviour of PET and PEN under uniaxial stress using experimental and molecular modelling techniques. Comparing experiment with modelling provides insights into polymer crystallisation with extended chains. Experimental x-ray diffraction patterns are reproduced by means of models of chains sliding along the c-axis leading to some loss of three-dimensional order, i.e. moving away from the condition of perfect register of the fully extended chains in triclinic crystals of both PET and PEN. This will help us understand the mechanism of polymer crystallisation under uniaxial stress and the appearance of mesophases in some cases as discussed herein.

Assembly of a Flexible 2,2ʹ-Oxydibenzoate and Silver(I) Ions to a Novel 3D Supramolecular Framework: Syntheses, Structure and Properties

2012 ◽  
Vol 67 (11) ◽  
pp. 1191-1196 ◽  
Author(s):  
Chong-Zhen Mei ◽  
Kai-Hui Li ◽  
Hai-Hua Li
Keyword(s):  
Hydrogen Bonding ◽  
Elemental Analysis ◽  
Self Assembly ◽  
Three Dimensional ◽  
Stacking Interactions ◽  
Supramolecular Architecture ◽  
Supramolecular Framework ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
X Ray

Self-assembly of silver(I) cations, flexible 2,2ʹ-oxydibenzoate anions (L2-), and 1,2-bis(4- pyridyl)ethane (bpa) ligands affords a new three-dimensional supramolecular architecture, {[Ag2(L)(bpa)2]⋅(H2O)4}n (1), which has been characterized by elemental analysis, IR, TGA, PXRD, and single-crystal X-ray diffraction. Complex 1exhibits layers further connected through hydrogen bonding and π...π stacking interactions. Its photoluminescence was also investigated.

scholarly journals Supramolecular frameworks based on [60]fullerene hexakisadducts

2017 ◽  
Vol 13 ◽  
pp. 1-9 ◽  
Author(s):  
Andreas Kraft ◽  
Johannes Stangl ◽  
Ana-Maria Krause ◽  
Klaus Müller-Buschbaum ◽  
Florian Beuerle
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Carboxylic Acid ◽  
Structural Integrity ◽  
Structure Stability ◽  
Side Chains ◽  
X Ray Diffraction ◽  
X Ray

[60]Fullerene hexakisadducts possessing 12 carboxylic acid side chains form crystalline hydrogen-bonding frameworks in the solid state. Depending on the length of the linker between the reactive sites and the malonate units, the distance of the [60]fullerene nodes and thereby the spacing of the frameworks can be controlled and for the most elongated derivative, continuous channels are obtained within the structure. Stability, structural integrity and porosity of the material were investigated by powder X-ray diffraction, thermogravimetry and sorption measurements.

Synthesis, Crystal Structure and Fluorescence Behavior of 2,6- Di(thiophen-2-yl)-benzo[1,2-d:4,5-d´]bisoxazole

2013 ◽  
Vol 68 (3) ◽  
pp. 239-244 ◽  
Author(s):  
Lan-Qin Chai ◽  
Yu-Li Zhang ◽  
Jun-Feng Tong ◽  
Gang Liu
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Emission Spectroscopy ◽  
3D Structure ◽  
Monoclinic Space Group ◽  
Stacking Interactions ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
C Nmr

An effective and clean new aerobic approach for the synthesis of 2,6-disubstituted benzobisoxazole by using a one-pot reaction of an organic aminoxyl radical as the catalyst is reported. 2,6- Di(thiophen-2-yl)-benzo[1,2-d : 4,5-d´]bisoxazole was synthesized with catalysis by the free radical 4-methoxy-TEMPO and characterized by 1H and 13C NMR spectroscopy, HRMS, as well as by elemental analysis, UV/Vis and emission spectroscopy. The crystal structure of the title compound has been determined by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group C2/c with a=12.531(1), b=3.8960(2), c = 28.733(2) Å, b = 100:760(1)°, Z = 4. Through intermolecular weak C-H· · ·O hydrogen bonding and p-p stacking interactions, a supramolecular 3D structure is formed.

Compound with Coexisting Mono- and Dinuclear Cu(II) Complexes Hosting a New Water Tape Cluster (H2O)22

2014 ◽  
Vol 69 (9-10) ◽  
pp. 987-994
Author(s):  
Wei Xu ◽  
Yue-Qing Zheng
Keyword(s):  
Complex Cation ◽  
Stacking Interactions ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Complex Molecules ◽  
X Ray ◽  
Thermoanalytical Techniques ◽  
Hydrogen Bond Interactions ◽  
Donor And Acceptor ◽  
2D Network

AbstractA new compound containing mono- and dinuclear Cu(II) complexes, [Cu2(phen)2(H2O)2(OH)2] [Cu(phen)2(CO3)]2(HCO3)2 · 22H2O] (phen=1,10-phenanthroline), has been prepared and characterized by X-ray diffraction analysis, thermoanalytical techniques and temperature-dependent magnetic susceptibility measurements. The hydroxo-bridged dinuclear [Cu2(phen)2(H2O)2(OH)2]2+ complex cations and the mononuclear [Cu(phen)2(CO3)] complex molecules are assembled via π···π stacking interactions into layers. A novel water tape containing (H2O)22 cluster units has been observed in the structure of the title complex. In hydrogen bond interactions HCO3- anions act as donor and acceptor to link the water tapes to form an infinite 2D network parallel to (010). According to the magnetic analyses, the coupling interactions in the dinuclear complex cation is ferromagnetic (J=34:5 cm-1)

Syntheses, structures, and properties of zinc(II) and copper(II) coordination polymers with imidazole-containing ligands

2019 ◽  
Vol 74 (10) ◽  
pp. 739-744
Author(s):  
Long Tang ◽  
Ye Guo ◽  
Shili Xue ◽  
Jijiang Wang ◽  
Xiangyang Hou ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Infrared Spectroscopy ◽  
Coordination Polymers ◽  
Supramolecular Structure ◽  
Stacking Interactions ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Structures And Properties ◽  
A Chain

AbstractThe reactions of Zn(NO3)2 · 6H2O/CuCl2 · 2H2O and 1,4-bis(1-imidazolyl)benzene (bib)/1,4-bis(1-imidazol-1-ylmethyl)benzene (biyb), carried out under hydrothermal conditions, produced two new coordination polymers [Zn(bib)(HCOO)2 · H2O] (1) and [Cu(biyb)Cl2] (2), respectively, which were characterized by elemental analysis, infrared spectroscopy, thermogravimetric analyses, and single-crystal X-ray diffraction. In complex 1, the ZnII centers are bridged by bib ligands to form a chain, where the adjacent chains are condensed by strong intermolecular O–H · · · O hydrogen-bonding and aromatic π-π stacking interactions to generate a 3D supramolecular structure. In 2, the CuII centers are bridged by biyb ligands to form, again, chains through C–H · · · Cl hydrogen bonds, and these adjacent chains with different orientations are joined to generate a 3D supramolecular structure.

Modified polyoxometalate: a novel monocapped bi-supporting and reduced α-Keggin structure {PMo12O40[Cu(2,2′-bpy)]}[Cu(2,2′-bpy)(en)(H2O)]2

2019 ◽  
Vol 75 (10) ◽  
pp. 1344-1352
Author(s):  
Yu-Kun Lu ◽  
Ya-Ping Li ◽  
Ling-Yu Yang ◽  
Wen-Hong Wang ◽  
Yuan Pan ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Hydrogen Bonding ◽  
Structural Analysis ◽  
Organic Pollutant ◽  
Three Dimensional ◽  
Supramolecular Network ◽  
Stacking Interactions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Π Stacking

A novel modified polyoxometalate, {PMo12O40[Cu(2,2′-bpy)]}[Cu(2,2′-bpy)(en)(H2O)]2 [2,2′-bpy is 2,2′-bipyridyl (C10H8N2) and en is ethylenediamine (C2H8N2)], has been synthesized hydrothermally and structurally characterized by elemental analysis, TG, IR, XPS and single-crystal X-ray diffraction. The structural analysis reveals that the compound contains the reduced Keggin polyanion [PMo12O40]6− as the parent unit, which is monocapped by [Cu(2,2′-bpy)]2+ fragments via four bridging O atoms on an {Mo4O4} pit and bi-supported by two [Cu(2,2′-bpy)(en)(H2O)]2+ coordination cations simultaneously. There exist strong intramolecular π–π stacking between the capping and supporting units, which play a stabilizing role during the crystallization of the compound. Adjacent POM clusters are further aggregated to form a three-dimensional supramolecular network through noncovalent forces, hydrogen bonding and π–π stacking interactions. In addition, the photocatalytic properties were investigated in detail, and the results indicated that the compound can be used as a photocatalyst towards the decomposition of the organic pollutant methylene blue (MB).

Synthesis, structure, and luminescent properties of two novel polynuclear complexes of 1,3-di(pyridin-2-yl)propane-1,3-dione

2012 ◽  
Vol 66 (1) ◽  
Author(s):  
Jin-Ting Tan ◽  
Wen-Jie Zhao ◽  
San-Ping Chen ◽  
Xia Li ◽  
Ying-Li Lu ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Elemental Analysis ◽  
Complex I ◽  
Luminescent Properties ◽  
Polynuclear Complexes ◽  
Stacking Interactions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Supramolecular Architectures ◽  
Solid Fluorescence

AbstractTwo complexes, {[Cd6(o-dppd)2(µ2-Cl)6(µ3-Cl)2(DMF)2(H2O)2Cl2]·DMF·CH3OH}n (I) (DMF = N,N-dimethylformamide; o-dppdH = 1,3-di(pyridin-2-yl)propane-1,3-dione) and [Cu4(o-dppd)2(OAc)4(OH)2]·4H2O (II), were synthesised and characterised by single-crystal X-ray diffraction, elemental analysis, IR, solid fluorescence and TGA. The results showed that complex I had a rodshaped polynuclear chain with hexacoordinating Cd atoms bridged by oxygen, µ2-Cl and µ3-Cl; complex II was a tetranuclear oligomer. In general, supramolecular architectures are constructed through hydrogen-bonding and π-π stacking interactions. I shows luminescence.

Self-Recognizing π-π Stacking Interactions Designed for the Generation of Ultrastable Mesoporous Hydrogen-Bonded Organic Frameworks

2019 ◽  
Author(s):  
KAIKAI MA ◽  
Peng Li ◽  
John Xin ◽  
Yongwei Chen ◽  
Zhijie Chen ◽  
...  
Keyword(s):  
Pore Size ◽  
Fiber Composite ◽  
Aqueous Media ◽  
Stacking Interactions ◽  
Mustard Gas ◽  
X Ray Diffraction ◽  
X Ray ◽  
Expansion Strategy ◽  
Π Stacking ◽  
Hydrogen Bonded

Creating crystalline porous materials with large pores is typically challenging due to undesired interpen-etration, staggered stacking, or weakened framework stability. Here, we report a pore size expansion strategy by self-recognizing π-π stacking interactions in a series of two-dimensional (2D) hydrogen–bonded organic frameworks (HOFs), HOF-10x (x=0,1,2), self-assembled from pyrene-based tectons with systematic elongation of π-conjugated molecular arms. This strategy successfully avoids interpene-tration or staggered stacking and expands the pore size of HOF materials to access mesoporous HOF-102, which features a surface area of ~ 2,500 m2/g and the largest pore volume (1.3 cm3/g) to date among all reported HOFs. More importantly, HOF-102 shows significantly enhanced thermal and chemical stability as evidenced by powder x-ray diffraction and N2 isotherms after treatments in chal-lenging conditions. Such stability enables the adsorption of dyes and cytochrome c from aqueous media by HOF-102 and affords a processible HOF-102/fiber composite for the efficient photochemical detox-ification of a mustard gas simulant.

scholarly journals X-ray and Neutron Study on the Structure of Hydrous SiO2 Glass up to 10 GPa

Minerals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 84 ◽  
Author(s):  
Satoru Urakawa ◽  
Toru Inoue ◽  
Takanori Hattori ◽  
Asami Sano-Furukawa ◽  
Shinji Kohara ◽  
...  
Keyword(s):  
Oxide Glasses ◽  
Void Space ◽  
X Ray Diffraction ◽  
Amorphous Sio2 ◽  
Sio2 Glass ◽  
X Ray ◽  
X Ray Scattering ◽  
Medium Range ◽  
Two Phases ◽  
A Minor

The structure of hydrous amorphous SiO2 is fundamental in order to investigate the effects of water on the physicochemical properties of oxide glasses and magma. The hydrous SiO2 glass with 13 wt.% D2O was synthesized under high-pressure and high-temperature conditions and its structure was investigated by small angle X-ray scattering, X-ray diffraction, and neutron diffraction experiments at pressures of up to 10 GPa and room temperature. This hydrous glass is separated into two phases: a major phase rich in SiO2 and a minor phase rich in D2O molecules distributed as small domains with dimensions of less than 100 Å. Medium-range order of the hydrous glass shrinks compared to the anhydrous SiO2 glass by disruption of SiO4 linkage due to the formation of Si–OD deuterioxyl, while the response of its structure to pressure is almost the same as that of the anhydrous SiO2 glass. Most of D2O molecules are in the small domains and hardly penetrate into the void space in the ring consisting of SiO4 tetrahedra.

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