scholarly journals Synthesis, structure and magnetocaloric properties of a new two-dimensional gadolinium(III) coordination polymer based on azobenzene-2,2′,3,3′-tetracarboxylic acid

2021 ◽  
Vol 77 (10) ◽  
pp. 591-598
Author(s):  
Wen-Wen Wei ◽  
Li-Ping Lu ◽  
Si-Si Feng ◽  
Miao-Li Zhu ◽  
Ulli Englert

A new Gd3+ coordination polymer (CP), namely, poly[diaqua[μ4-1′-carboxy-3,3′-(diazene-1,2-diyl)dibenzene-1,2,2′-tricarboxylato]gadolinium(III)], [Gd(C16H7N2O8)(H2O)2] n , (I), has been synthesized hydrothermally from Gd(NO3)3·6H2O and azobenzene-2,2′,3,3′-tetracarboxylic acid (H4abtc). The target solid has been characterized by single-crystal and powder X-ray diffraction, elemental analysis, IR spectroscopy and susceptibility measurements. CP (I) crystallizes in the monoclinic space group C2/c. The structure features a 4-connected topology in which Gd3+ ions are connected by carboxylate groups into a linear chain along the monoclinic symmetry direction. Adjacent one-dimensional aggregates are bridged by Habtc3− ligands to form a two-dimensional CP in the (10-1) plane. A very short hydrogen bond [O...O = 2.4393 (4) Å] links neighbouring layers into a three-dimensional network. A magnetic study revealed antiferromagnetic Gd...Gd coupling within the chain direction. CP (I) displays a significant magnetocaloric effect (MCE), with a maximum −ΔS m of 27.26 J kg−1 K−1 for ΔH = 7 T at 3.0 K. As the MCE in (I) exceeds that of the commercial magnetic refrigerant GGG (Gd3Ga5O12, −ΔS m = 24 J kg−1 K−1, ΔH = 30 kG), CP (I) can be regarded as a potential cryogenic material for low-temperature magnetic refrigeration.

2015 ◽  
Vol 71 (4) ◽  
pp. 306-310 ◽  
Author(s):  
Qiu-Ying Huang ◽  
Yu-Hong Zhang ◽  
Xiang-Ru Meng

In the title coordination polymer,catena-poly[[bis[{1-[(1H-benzimidazol-2-yl-κN3)methyl]-1H-tetrazole}zinc(II)]-bis(μ4-pentane-1,5-dioato-1:2:1′:2′κ4O1:O1′:O5:O5′)] methanol disolvate], {[Zn(C5H6O4)(C9H8N6)]·CH3OH}n, each ZnIIion is five-coordinated by four O atoms from four glutarate ligands and by one N atom from a 1-[(1H-benzimidazol-2-yl)methyl]-1H-tetrazole (bimt) ligand, leading to a slightly distorted square-pyramidal coordination environment. Two ZnIIions are linked by four bridging glutarate carboxylate groups to generate a dinuclear [Zn2(CO2)4] paddle-wheel unit. The dinuclear units are further connected into a one-dimensional chainviathe glutarate ligands. The bimt ligands coordinate to the ZnIIions in a monodentate mode and are pendant on both sides of the main chain. In the crystal, the chains are linked by O—H...O and N—H...O hydrogen bonds into a two-dimensional layered structure. Adjacent layers are further packed into a three-dimensional network through van der Waals forces. A thermogravimetric analysis was carried out and the photoluminescent behaviour of the polymer was investigated.


2006 ◽  
Vol 62 (7) ◽  
pp. m1550-m1552 ◽  
Author(s):  
Zi-Lu Chen ◽  
Yu-Zhen Zhang ◽  
Fu-Pei Liang

In the title compound, [Gd(C7H6NO2)3(H2O)] n , a two-dimensional coordination polymer, the eight-coordinate GdIII ions are bridged by two carboxylate groups from two μ2-p-aminobenzoate ligands, forming a centrosymmetric dinuclear block. These blocks are further connected by μ3-p-aminobenzoate ligands, yielding a two-dimensional network. The coordination polymers thus formed are connected via hydrogen bonds, producing a three-dimensional supramolecular structure.


2014 ◽  
Vol 70 (5) ◽  
pp. 517-521
Author(s):  
Yu-Xiu Jin ◽  
Fang Yang ◽  
Li-Min Yuan ◽  
Chao-Guo Yan ◽  
Wen-Long Liu

In poly[[μ3-2,2′-(disulfanediyl)dibenzoato-κ5 O:O,O′:O′′,O′′′](1,10-phenanthroline-κ2 N,N′)cadmium(II)], [Cd(C14H8O4S2)(C12H8N2)] n , the asymmetric unit contains one CdII cation, one 2,2′-(disulfanediyl)dibenzoate anion (denoted dtdb2−) and one 1,10-phenanthroline ligand (denoted phen). Each CdII centre is seven-coordinated by five O atoms of bridging/chelating carboxylate groups from three dtdb2− ligands and by two N atoms from one phen ligand, forming a distorted pentagonal–bipyramidal geometry. The CdII cations are bridged by dtdb2− anions to give a two-dimensional (4,4) layer. The layers are stacked to generate a three-dimensional supramolecular architecture via a combination of aromatic C—H...π and π–π interactions. The thermogravimetric and luminescence properties of this compound were also investigated.


2019 ◽  
Vol 75 (2) ◽  
pp. 141-149 ◽  
Author(s):  
Feng Su ◽  
Cheng-Yong Zhou ◽  
Lin-Tao Wu ◽  
Xi Wu ◽  
Chun Han ◽  
...  

Coordination polymers constructed from conjugated organic ligands and metal ions with a d 10 electronic configuration exhibit intriguing properties for chemical sensing and photochemistry. A ZnII-based coordination polymer, namely poly[aqua(μ6-biphenyl-3,3′,5,5′-tetracarboxylato)(μ2-4,4′-bipyridine)dizinc(II)], [Zn2(C16H6O8)(C10H8N2)(H2O)2] n or [Zn2(m,m-bpta)(4,4′-bipy)(H2O)2] n , was synthesized from a mixture of biphenyl-3,3′,5,5′-tetracarboxylic acid [H4(m,m-bpta)], 4,4′-bipyridine (4,4′-bipy) and Zn(NO3)2·6H2O under solvothermal conditions. The title complex has been structurally characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction and powder X-ray diffraction analysis, and features a μ6-coordination mode. The ZnII ions adopt square-pyramidal geometries and are bridged by two syn–syn carboxylate groups to form [Zn2(COO)2] secondary buildding units (SBUs). The SBUs are crosslinked by (m,m-bpta)4− ligands to produce a two-dimensional grid-like layer that exhibits a stair-like structure along the a axis. Adjacent layers are linked by 4,4′-bipy ligands to form a three-dimensional network with a {44.610.8}{44.62} topology. In the solid state, the complex displays a strong photoluminescence and an excellent solvent stability. In addition, the luminescence sensing results indicate a highly selective and sensitive sensing for Fe3+ ions.


2009 ◽  
Vol 65 (3) ◽  
pp. m118-m120
Author(s):  
Olha Sereda ◽  
Helen Stoeckli-Evans

The title coordination polymer, [Cd3Co2(CN)12(C2H8N2)4]n, has an infinite two-dimensional network structure. The asymmetric unit is composed of two crystallographically independent CdIIatoms, one of which is located on a twofold rotation axis. There are two independent ethylenediamine (en) ligands, one of which bis-chelates to the Cd atom that sits in a general position, while the other bridges this Cd atom to that sitting on the twofold axis. The Cd atom located on the twofold rotation axis is linked to four equivalent CoIIIatomsviacyanide bridges, while the Cd atom that sits in a general position is connected to three equivalent CoIIIatomsviacyanide bridges. In this way, a series of trinuclear, tetranuclear and pentanuclear macrocycles are linked to form a two-dimensional network structure lying parallel to thebcplane. In the crystal structure, these two-dimensional networks are linkedviaN—H...N hydrogen bonds involving an en NH2H atom and a cyanide N atom, leading to the formation of a three-dimensional structure. This coordination polymer is only the second example involving a cyanometallate where the en ligand is present in both chelating and bridging coordination modes.


2011 ◽  
Vol 66 (4) ◽  
pp. 355-358
Author(s):  
Man-Sheng Chen ◽  
Yi-Fang Deng ◽  
Zhi-Min Chen ◽  
Chun-Hua Zhang ◽  
Dai-Zhi Kuang

A unique 3D fourfold interpenetrated metal-organic framework, [Co(L)(H2O)2]・H2O (1), has been synthesized by the solvothermal reaction of H2L with Co(NO3)2・6H2O (H2L = 5-(isonicotinamido) isophthalic acid). Compound 1 crystallizes in the monoclinic space group P21/c, with the cell parameters: a = 81301(8), b = 107711(11), c = 167697(16) Å , β = 92.656(2) °, V = 14669(3) Å3, R1 = 0.0325 and wR2 = 0.0833. Its framework has (10,3)-b topology, where the cobalt atoms are alternately bridged by the pyridyl and the carboxylate groups of the L2− ligands into a three-dimensional network. Compound 1 displays antiferromagnetic interactions. Above 40 K, χm −1 obeys the Curie- Weiss law with C = 3.28 emu Kmol−1 andΘ = −0.66 K.


2015 ◽  
Vol 71 (11) ◽  
pp. 1010-1016 ◽  
Author(s):  
Shridhar H. Thorat ◽  
Sanjay Kumar Sahu ◽  
Rajesh G. Gonnade

The synthesis of pharmaceutical cocrystals is a strategy to enhance the performance of active pharmaceutical ingredients (APIs) without affecting their therapeutic efficiency. The 1:1 pharmaceutical cocrystal of the antituberculosis drug pyrazinamide (PZA) and the cocrystal formerp-aminobenzoic acid (p-ABA), C7H7NO2·C5H5N3O, (1), was synthesized successfully and characterized by relevant solid-state characterization methods. The cocrystal crystallizes in the monoclinic space groupP21/ncontaining one molecule of each component. Both molecules associateviaintermolecular O—H...O and N—H...O hydrogen bonds [O...O = 2.6102 (15) Å and O—H...O = 168.3 (19)°; N...O = 2.9259 (18) Å and N—H...O = 167.7 (16)°] to generate a dimeric acid–amide synthon. Neighbouring dimers are linked centrosymmetrically through N—H...O interactions [N...O = 3.1201 (18) Å and N—H...O = 136.9 (14)°] to form a tetrameric assembly supplemented by C—H...N interactions [C...N = 3.5277 (19) Å and C—H...N = 147°]. Linking of these tetrameric assemblies through N—H...O [N...O = 3.3026 (19) Å and N—H...O = 143.1 (17)°], N—H...N [N...N = 3.221 (2) Å and N—H...N = 177.9 (17)°] and C—H...O [C...O = 3.5354 (18) Å and C—H...O = 152°] interactions creates the two-dimensional packing. Recrystallization of the cocrystals from the molten state revealed the formation of 4-(pyrazine-2-carboxamido)benzoic acid, C12H9N3O3, (2), through a transamidation reaction between PZA andp-ABA. Carboxamide (2) crystallizes in the triclinic space groupP-1 with one molecule in the asymmetric unit. Molecules of (2) form a centrosymmetric dimeric homosynthon through an acid–acid O—H...O hydrogen bond [O...O = 2.666 (3) Å and O—H...O = 178 (4)°]. Neighbouring assemblies are connected centrosymmetricallyviaa C—H...N interaction [C...N = 3.365 (3) Å and C—H...N = 142°] engaging the pyrazine groups to generate a linear chain. Adjacent chains are connected looselyviaC—H...O interactions [C...O = 3.212 (3) Å and C—H...O = 149°] to generate a two-dimensional sheet structure. Closely associated two-dimensional sheets in both compounds are stackedviaaromatic π-stacking interactions engaging the pyrazine and benzene rings to create a three-dimensional multi-stack structure.


2006 ◽  
Vol 62 (7) ◽  
pp. m1620-m1622 ◽  
Author(s):  
Bin Yu ◽  
Xiao-Qing Wang ◽  
Ru-Ji Wang ◽  
Guang-Qiu Shen ◽  
De-Zhong Shen

The HoIII center in the title coordination polymer, {[Ho2(C4H4O4)3(H2O)2]·H2O} n , is nine-coordinated in a tricapped trigonal prism by eight O atoms, derived from six carboxylate groups and a water molecule. One of the independent succinate anions is located about a crystallographic center of inversion and the uncoordinated water molecule lies on a twofold axis. The crystal structure comprises edge-shared HoO9 polyhedra linked by succinate bridges, forming a three-dimensional network structure.


2014 ◽  
Vol 70 (7) ◽  
pp. 650-653
Author(s):  
Lei-Lei Liu ◽  
Cai-Xia Yu ◽  
Lei Hua ◽  
Lu Lin

In the title coordination polymer, [Pb(C14H8N2O4)(CH3OH)2]n, the asymmetric unit contains half of a PbIIcation, half of a 2,2′-(diazene-1,2-diyl)dibenzoate dianionic ligand (denotedL2−) and one methanol ligand. Each PbIIcentre is eight-coordinated by six O atoms of chelating/bridging carboxylate groups from fourL2−ligands and two O atoms from two terminal methanol ligands, forming a distorted dodecahedron. The [PbL2(MeOH)2] subunits are interlinkedviathe sharing of two carboxylate O atoms to form a one-dimensional [PbL2(MeOH)2]nchain. Adjacent chains are further connected byL2−ligands, giving rise to a two-dimensional layer, and these layers are bridged byL2−linkers to afford a three-dimensional framework with a 41263topology.


1996 ◽  
Vol 49 (7) ◽  
pp. 835 ◽  
Author(s):  
XM Chen ◽  
ML Tong ◽  
YJ Luo ◽  
ZN Chen

An example of a 4,4'-bipyridine ( γbpy ) clathrate in its copper(II) complex has been established. The compound, [Cu( γbpy )(H2O)2(ClO4)2]n.( γbpy )n, crystallizes in the monoclinic space group C2/c with a 16.651(3), b 11.089(2), c 14.360(3) Ǻ, β 116.45(3)°, V 2373.9(8)Ǻ3. The crystal structure comprises γbpy -bridged linear polymeric [Cu( γbpy )(H2O)2(ClO4)2]n chains, where the copper atom, located on a crystallographic twofold axis, is coordinated in an elongated octahedral environment by two nitrogen atoms of the bridging γbpy ligands (Cu-N 1.998(4)Ǻ) and two water molecules (Cu-O 1.968(3)Ǻ) at the equatorial positions, and two perchlorate oxygen atoms at the axial positions (Cu-O 2.414(4)Ǻ). The chains are interconnected by hydrogen bonds between the aqua ligands and the uncoordinated perchlorate oxygen atoms to form two-dimensional layers with cavities each enclosing a γbpy molecule. Hydrogen bonding between the aqua ligands and the nitrogen atoms of the solvate γbpy molecules further extends the structure into a three-dimensional network in the solid.


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