Coordination Polymers Constructed from TCNQ2– Anions and Chelating Ligands

2014 ◽  
Vol 67 (12) ◽  
pp. 1871 ◽  
Author(s):  
Brendan F. Abrahams ◽  
Robert W. Elliott ◽  
Richard Robson

Coordination polymers containing tetracyanoquinodimethane (TCNQ) in its dianionic form, TCNQ–II, have been formed by combining the acid form of the dianion, TCNQH2, with divalent metal centres in the presence of chelating ligands such as 2,2′-bipyridine (bipy) and 1,10-phenanthroline (phen). When MnII or CdII is employed, two-dimensional (2D) corrugated sheet structures with the formula MII(TCNQ–II)L (M = Mn, Cd; L = bipy, phen) are obtained. In contrast, when CoII is used as the metal centre a complex three-dimensional (3D) structure of composition [CoII(TCNQ–II)(phen)] is formed. Despite the significant differences between the 2D and 3D network structures, the metal coordination geometry and the binding mode of the TCNQ dianion are very similar in all cases.

2019 ◽  
Vol 75 (4) ◽  
pp. 443-450
Author(s):  
Guiying Zhu ◽  
Yang Lu ◽  
Guoxia Jin ◽  
Xuan Ji ◽  
Jianping Ma

Three new one- (1D) and two-dimensional (2D) CuII coordination polymers, namely poly[[bis{μ2-4-amino-3-(pyridin-2-yl)-5-[(pyridin-3-ylmethyl)sulfanyl]-1,2,4-triazole}copper(II)] bis(methanesulfonate) tetrahydrate], {[Cu(C13H12N5S)2](CH3SO3)2·4H2O} n (1), catena-poly[[copper(II)-bis{μ2-4-amino-3-(pyridin-2-yl)-5-[(pyridin-4-ylmethyl)sulfanyl]-1,2,4-triazole}] dinitrate methanol disolvate], {[Cu(C13H12N5S)2](NO3)2·2CH3OH} n (2), and catena-poly[[copper(II)-bis{μ2-4-amino-3-(pyridin-2-yl)-5-[(pyridin-4-ylmethyl)sulfanyl]-1,2,4-triazole}] bis(perchlorate) monohydrate], {[Cu(C13H12N5S)2](ClO4)2·H2O} n (3), were obtained from 4-amino-3-(pyridin-2-yl)-5-[(pyridin-3-ylmethyl)sulfanyl]-1,2,4-triazole with pyridin-3-yl terminal groups and from 4-amino-3-(pyridin-2-yl)-5-[(pyridin-4-ylmethyl)sulfanyl]-1,2,4-triazole with pyridin-4-yl terminal groups. Compound 1 displays a 2D net-like structure. The 2D layers are further linked through hydrogen bonds between methanesulfonate anions and amino groups on the framework and guest H2O molecules in the lattice to form a three-dimensional (3D) structure. Compound 2 and 3 exhibit 1D chain structures, in which the complicated hydrogen-bonding interactions play an important role in the formation of the 3D network. These experimental results indicate that the coordination orientation of the heteroatoms on the ligands has a great influence on the polymeric structures. Moreover, the selection of different counter-anions, together with the inclusion of different guest solvent molecules, would also have a great effect on the hydrogen-bonding systems in the crystal structures.


2019 ◽  
Vol 75 (5) ◽  
pp. 575-583 ◽  
Author(s):  
Yuting Bai ◽  
Meirong Han ◽  
Enxi Wu ◽  
Sisi Feng ◽  
Miaoli Zhu

Two three-dimensional (3D) CdII coordination polymers, namely poly[[di-μ-aqua-diaquabis{μ5-4,4′,4′′-[benzene-1,3,5-triyltris(oxy)]tribenzoato}tricadmium(II)] dihydrate], {[Cd3(C27H15O9)2(H2O)4]·2H2O} n , (I), and poly[[aqua{μ6-4,4′,4′′-[benzene-1,3,5-triyltris(oxy)]tribenzoato}(μ-formato)[μ-1,1′-(1,4-phenylene)bis(1H-imidazole)]dicadmium(II)] dihydrate], {[Cd2(C27H15O9)(C12H10N4)(HCOO)(H2O)]·2H2O} n , (II), have been hydrothermally synthesized from the reaction system containing Cd(NO3)2·4H2O and the flexible tripodal ligand 1,3,5-tris(4-carboxyphenoxy)benzene (H3tcpb) via tuning of the auxiliary ligand. Both complexes have been characterized by single-crystal X-ray diffraction analysis, elemental analysis, IR spectra, powder X-ray diffraction and thermogravimetric analysis. Complex (I) is a 3D framework constructed from trinuclear structural units and tcpb3− ligands in a μ5-coordination mode. The central CdII atom of the trinuclear unit is located on a crystallographic inversion centre and adopts an octahedral geometry. The metal atoms are bridged by four syn–syn carboxylate groups and two μ2-water molecules to form trinuclear [Cd3(COO)4(μ2-H2O)2] secondary building units (SBUs). These SBUs are incorporated into clusters by bridging carboxylate groups to produce pillars along the c axis. The one-dimensional inorganic pillars are connected by tcpb3− linkers in a μ5-coordination mode, thus forming a 3D network; its topology corresponds to the point symbol (42.62.82)(44.62)2(45.66.84)2. In contrast to (I), complex (II) is characterized by a 3D framework based on dinuclear cadmium SBUs, i.e. [Cd2(COO)3]. The two symmetry-independent CdII ions display different coordinated geometries, namely octahedral [CdN2O4] and monocapped octahedral [CdO7]. The dinuclear SBUs are incorporated into clusters by bridging formate groups to produce pillars along the c axis. These pillars are further bridged either by tcpb3− ligands into sheets or by 1,4-bis(imidazol-1-yl)benzene ligands into undulating layers, and finally these two-dimensional surfaces interweave, forming a 3D structure with the point symbol (4.62)(47.614). Compound (II) exhibits reversible I2 uptake of 56.8 mg g−1 with apparent changes in the visible colour and the UV–Vis and fluorescence spectra, and therefore may be regarded as a potential reagent for the capture and release of I2.


2020 ◽  
Vol 842 ◽  
pp. 63-68
Author(s):  
Xiao Zhang ◽  
Jian Zheng ◽  
Yong Qiang Du ◽  
Chun Ming Zhang

Three-dimensional (3D) network structure has been recognized as an efficient approach to enhance the mechanical and thermal conductive properties of polymeric composites. However, it has not been applied in energetic materials. In this work, a fluoropolymer based composite with vertically oriented and interconnected 3D graphite network was fabricated for polymer bonded explosives (PBXs). Here, the graphite and graphene oxide platelets were mixed, and self-assembled via rapid freezing and using crystallized ice as the template. The 3D structure was finally obtained by freezing-dry, and infiltrating with polymer. With the increasing of filler fraction and cooling rate, the thermal conductivity of the polymer composite was significantly improved to 2.15 W m-1 K-1 by 919% than that of pure polymer. Moreover, the mechanical properties, such as tensile strength and elastic modulus, were enhanced by 117% and 563%, respectively, when the highly ordered structure was embedded in the polymer. We attribute the increased thermal and mechanical properties to this 3D network, which is beneficial to the effective heat conduction and force transfer. This study supports a desirable way to fabricate the strong and thermal conductive fluoropolymer composites used for the high-performance polymer bonded explosives (PBXs).


CISM journal ◽  
1990 ◽  
Vol 44 (1) ◽  
pp. 9-18 ◽  
Author(s):  
Michael G. Sideris

The geoid and its horizontal derivatives, the deflections of the vertical, play an important role in the adjustment of geodetic networks. In the one-dimensional (1D) case, represented typically by networks of orthometric heights, the geoid provides the reference surface for the measurements. In the two-dimensional (2D) adjustment of horizontal control networks, the geoidal undulations N and deflections of the vertical ξ, η are needed for the reduction of the measured quantities onto the reference ellipsoid. In the three-dimensional (3D) adjustment, N and ξ, η are basically required to relate geodetic and astronomic quantities. The paper presents the major gravimetric methods currently used for predicting ξ, η and N, and briefly intercompares them in terms of accuracy, efficiency, and data required. The effects of N, ξ, η on various quantities used in the ID, 2D, and 3D network adjustments are described explicitly for each case and formulas are given for the errors introduced by either neglecting or using erroneous N, ξ, η in the computational procedures.


2019 ◽  
Vol 75 (8) ◽  
pp. 1073-1083 ◽  
Author(s):  
Feng Su ◽  
Cheng-Yong Zhou ◽  
Lin-Tao Wu ◽  
Xi Wu ◽  
Jing Su ◽  
...  

Two CoII-based coordination polymers, namely poly[(μ4-biphenyl-2,2′,5,5′-tetracarboxylato){μ2-1,3-bis[(1H-imidazol-1-yl)methyl]benzene}dicobalt(II)], [Co2(C16H6O8)(C14H14N4)2] n or [Co2(o,m-bpta)(1,3-bimb)2] n (I), and poly[[aqua(μ4-biphenyl-2,2′,5,5′-tetracarboxylato){1,4-bis[(1H-imidazol-1-yl)methyl]benzene}dicobalt(II)] dihydrate], {[Co2(C16H6O8)(C14H14N4)2(H2O)2]·4H2O} n or {[Co2(o,m-bpta)(1,4-bimb)2(H2O)2]·4H2O} n (II), were synthesized from a mixture of biphenyl-2,2′,5,5′-tetracarboxylic acid, i.e. [H4(o,m-bpta)], CoCl2·6H2O and N-donor ligands under solvothermal conditions. The complexes were characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction and powder X-ray diffraction analysis. The bridging (o,m-bpta)4− ligands combine with CoII ions in different μ4-coordination modes, leading to the formation of one-dimensional chains. The central CoII atoms display tetrahedral [CoN2O2] and octahedral [CoN2O4] geometries in I and II, respectively. The bis[(1H-imidazol-1-yl)methyl]benzene (bimb) ligands adopt trans or cis conformations to connect CoII ions, thus forming two three-dimensional (3D) networks. Complex I shows a (2,4)-connected 3D network with left- and right-handed helical chains constructed by (o,m-bpta)4− ligands. Complex II is a (4,4)-connected 3D novel network with ribbon-like chains formed by (o,m-bpta)4− linkers. Magnetic studies indicate an orbital contribution to the magnetic moment of I and II due to the longer Co...Co distances. An attempt has been made to fit the χM T results to the magnetic formulae for mononuclear CoII complexes, the fitting indicating the presence of weak antiferromagnetic interactions between the CoII ions.


IUCrData ◽  
2019 ◽  
Vol 4 (4) ◽  
Author(s):  
Laura Gasque ◽  
Óscar Guzmán-Méndez ◽  
Sylvain Bernès

The title compound, [Gd(C11H7O4)3(C2H5OH)(H2O)]·C2H5OH, was crystallized from ethanol, affording a solvate. The main ligand in the complex results from deprotonation of the hydroxy group in 3-acetyl-4-hydroxycoumarin (C11H8O4) and the resulting anionic ligands chelate the GdIII centre. Three anions, one ethanol and one water molecule are bonded to the lanthanide, giving an eight-coordinate metal centre with a slightly distorted trigonal–prismatic square-face-bicapped coordination geometry. All water and ethanol molecules participate in an intricate three-dimensional framework of hydrogen bonds. The complex is isostructural to the Tb and Dy compounds reported previously [Guzmán-Méndez et al. (2018). Inorg. Chem. 57, 908–911].


2019 ◽  
Vol 75 (11) ◽  
pp. 1664-1671 ◽  
Author(s):  
Sailesh Chettri ◽  
Dhiraj Brahman ◽  
Biswajit Sinha ◽  
Mukesh M. Jotani ◽  
Edward R. T. Tiekink

The crystal and molecular structures of the title CuII complex, isolated as a dihydrate, [Cu(C21H14N3O3)2]·2H2O, reveals a highly distorted coordination geometry intermediate between square-planar and tetrahedral defined by an N2O2 donor set derived from two mono-anionic bidentate ligands. Furthermore, each six-membered chelate ring adopts an envelope conformation with the Cu atom being the flap. In the crystal, imidazolyl-amine-N—H...O(water), water-O—H...O(coordinated, nitro and water), phenyl-C—H...O(nitro) and π(imidazolyl)–π(nitrobenzene) [inter-centroid distances = 3.7452 (14) and 3.6647 (13) Å] contacts link the components into a supramolecular layer lying parallel to (101). The connections between layers forming a three-dimensional architecture are of the types nitrobenzene-C—H...O(nitro) and phenyl-C—H...π(phenyl). The distorted coordination geometry for the CuII atom is highlighted in an analysis of the Hirshfeld surface calculated for the metal centre alone. The significance of the intermolecular contacts is also revealed in a study of the calculated Hirshfeld surfaces; the dominant contacts in the crystal are H...H (41.0%), O...H/H...O (27.1%) and C...H/H...C (19.6%).


Author(s):  
Zhi-Guo Zhong ◽  
Yu-Quan Feng ◽  
Ping Zhang

A novel copper–niobium oxyfluoride, {[Cu2(C10H7N2O)2][NbOF4]}n, has been synthesized by a hydrothermal method and characterized by elemental analysis, EDS, IR, XPS and single-crystal X-ray diffraction. The structural unit consists of oneC2-symmetric [NbOF4]−anion and one centrosymmetric coordinated [Cu2(obpy)2]+cation (obpy is 2,2′-bipyridin-6-olate). In the [NbOF4]−anion, each NbVmetal centre is five-coordinated by four F atoms and one O atom in the first coordination shell, forming a square-pyramidal coordination geometry. These square pyramids are then further connected to each othervia transO atoms [Nb—O = 2.187 (3) Å], forming an infinite linear {[NbOF4]−}npolyanion. In the coordinated [Cu2(obpy)2]+cation, the oxidation state of each Cu site is disordered, which is confirmed by the XPS results. The disordered Cu sites are coordinated by two N atoms and one O atom from two different obpy ligands. The [NbOF4]−and [Cu2(obpy)2]+units are assembledviaweak C—H...F hydrogen bonds, resulting in the formation of a three-dimensional supramolecular structure. π–π stacking interactions between the pyridine rings [centroid–centroid distance = 3.610 (2) Å] may further stabilize the crystal structure.


2015 ◽  
Vol 68 (6) ◽  
pp. 906
Author(s):  
Zhuo-Wei Wang ◽  
Hui Zhao ◽  
Min Hu ◽  
Chun-Sen Liu

Two distinct three-dimensional (3D) CdII coordination polymers with 1,2-naphthalenedicarboxylate (ndc2–) and dipyridyl co-ligands have been synthesized under hydrothermal conditions. Interestingly, the slight difference in the two 4,4′-dipyridyl building blocks, namely, 1,2-bi(4-pyridyl)ethane (bpp) and 1,2-bi(4-pyridyl)ethene (bpe) with C–C or C=C spacers, results in the significant structural divergence of the resultant coordination polymers. Structural analysis reveals that complexes [Cd(ndc)(bpp)(H2O)]n (1) and {[Cd5(ndc)4(bpe)2(OH)2](H2O)1.5}n (2) are constructed by discrete metal–carboxylate dimeric units and metal–carboxylate chains, respectively, which are further extended by bpp or bpe linkers to form the inclined interpenetrated two-dimensional (2D)→3D network for 1 and the 3D porous framework for 2. This result reveals that the flexibility of auxiliary ligands plays an important role in the structural assemblies of coordination networks. The thermal and luminescence properties of both complexes were also investigated in solid state.


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