A thermal- and light-induced switchable one-dimensional rare loop-like spin crossover coordination polymer

2019 ◽  
Vol 48 (45) ◽  
pp. 17014-17021 ◽  
Author(s):  
Wenlong Lan ◽  
Francisco Javier Valverde-Muñoz ◽  
Yong Dou ◽  
Xiaoyun Hao ◽  
M. Carmen Muñoz ◽  
...  

The looped-like 1D coordination polymer {Fe(DPIP)2(NCSe)2}n·4DMF displays a thermal and light spin crossover behavior strongly dependent on the occurrence of intermolecular hydrogen bonds between the ligand amide functions and the solvent molecules.

2017 ◽  
Vol 4 (6) ◽  
pp. 921-926 ◽  
Author(s):  
Zheng Yan ◽  
Long-Feng Zhu ◽  
Lian-Wen Zhu ◽  
Yan Meng ◽  
Md. Najbul Hoque ◽  
...  

A ladder-type 1D coordination polymer with enhanced spin-crossover behaviour is reported. It showed an abrupt spin transition above room temperature with a 3 K hysteresis (T1/2↓ = 335 K andT1/2↑ = 338 K).


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3358
Author(s):  
Sadaf Rauf ◽  
Agata Trzesowska-Kruszynska ◽  
Tomasz Sierański ◽  
Marcin Świątkowski

Three new copper coordination compounds derived from 2,2-bis(hydroxymethyl)propionic acid (dmpa) and hexamethylenetetramine (hmta) were obtained and their crystal structures were determined. The stoichiometry of the reagents applied in the syntheses reflects the metal to ligand molar ratio in the formed solid products. Due to the multiple coordination modes of the used ligands, wide structural diversity was achieved among synthesized compounds, i.e., mononuclear [Cu(dmp)2(hmta)2(H2O)] (1), dinuclear [Cu2(dmp)4(hmta)2] (2), and 1D coordination polymer [Cu2(dmp)4(hmta)]n (3). Their supramolecular structures are governed by O—H•••O and O—H•••N hydrogen bonds. The compounds were characterized in terms of absorption (UV-Vis and IR) and thermal properties. The relationships between structural features and properties were discussed in detail. Owing to discrepancies in the coordination mode of a dmp ligand, bidentate chelating in 1, and bidentate bridging in 2 and 3, there is a noticeable change in the position of the bands corresponding to the stretching vibrations of the carboxylate group in the IR spectra. The differences in the structures of the compounds are also reflected in the nature and position of the UV-Vis absorption maxima, which are located at lower wavelengths for 1.


2015 ◽  
Vol 71 (8) ◽  
pp. m148-m149
Author(s):  
Mohammad Iqbal ◽  
James Raftery ◽  
Peter Quayle

The title copper(II) complex, {(C27H37N2)[Cu4(CH3COO)8Cl]·3CH2Cl2}n, is a one-dimensional coordination polymer. The asymmetric unit is composed of a copper(II) tetraacetate paddle-wheel complex, a Cl−anion situated on a twofold rotation axis, half a 1,3-bis(2,6-diisopropylphenyl)imidazolium cation (the whole molecule being generated by twofold rotation symmetry) and one and a half of a dichloromethane solvent molecule (one being located about a twofold rotation axis). The central metal-organic framework comprises of a tetranuclear copper(II) acetate `paddle-wheel' complex which arises from the dimerization of the copper(II) tetraacetate core comprising of three μ2-bidentate acetate and one μ3-tridentate acetate ligands per binuclear paddle-wheel complex. Both CuIIatoms of the binuclear component adopt a distorted square-pyramidal coordination geometry (τ = 0.04), with a Cu...Cu separation of 2.6016 (2) Å. The apical coordination site of one CuIIatom is occupied by an O atom of a neighbouring acetate bridge [Cu—O = 2.200 (2) Å], while that of the second CuIIatom is occupied by a bridging chloride ligand [Cu...Cl = 2.4364 (4) Å]. The chloride bridge is slightly bent with respect to the Cu...Cu internuclear axis [Cu—Cl—Cu = 167.06 (6)°] and the tetranuclear units are located about a twofold rotation axis, forming the one-dimensional polymer that propagates along [101]. Charge neutrality is maintained by the inclusion of the 1,3-bis(2,6-diisopropylphenyl)imidazolium cation within the crystal lattice. In the crystal, the cation and dichloromethane solvent molecules are linked to the coordination polymer by various C—H...O and C—H...Cl hydrogen bonds. There are no other significant intermolecular interactions present.


Sci ◽  
2020 ◽  
Vol 2 (3) ◽  
pp. 66
Author(s):  
Manuel Baumgartner ◽  
Raphael Schaller ◽  
Paul Smith ◽  
Irene Weymuth ◽  
Walter Caseri

The coordination polymer [Fe(NH2trz)3](2ns)2 exhibits the rare phenomenon of spin crossover in an attractive temperature range, i.e., somewhat above room temperature. Spin crossover in [Fe(NH2trz)3](2ns)2 is manifest by thermochromism, which is accompanied by a magnetic transition from diamagnetism to paramagnetism. However, [Fe(NH2trz)3](2ns)2 is brittle and difficult to process, which limits its use. In this study, we show that [Fe(NH2trz)3](2ns)2 can be co-processed with ultrahigh molecular weight polyethylene (UHMWPE), which possesses outstanding mechanical properties, particularly when tensile drawn. Therefore, [Fe(NH2trz)3](2ns)2–UHMWPE blends were gel-processed by extrusion, employing a relatively poor solvent, which has recently been shown to offer advantages compared to good solvents. Uniform and flexible films, ribbons and fibers with [Fe(NH2trz)3](2ns)2 fractions as high as 33.3% m/m were obtained that could be readily drawn. Spin crossover in the coordination polymer is retained in these materials, as evident from their thermochromism. The tensile strength and Young’s modulus of the blends exceed those of typical commodity polymers. Thus, the films, ribbons and fibers constitute a special class of multifunctional materials that combine the flexibility and excellent mechanical properties of drawn UHMWPE with the spin crossover behavior of [Fe(NH2trz)3](2ns)2.


2013 ◽  
Vol 69 (9) ◽  
pp. 1017-1021
Author(s):  
Liu-cheng Gui ◽  
Guang-ming Liang ◽  
Hua-hong Zou ◽  
Zhong Hou

The title complexes, poly[[bis[μ2-2-ethyl-1-(pyridin-3-ylmethyl)-1H-benzimidazole-κ2N1:N3]copper(I)] tetrafluoroborate acetonitrile monosolvate], {[Cu(C15H15N3)2]BF4·CH3CN}n, (I), and poly[[bis[μ2-2-ethyl-1-(pyridin-3-ylmethyl)-1H-benzimidazole-κ2N1:N3]silver(I)] perchlorate methanol monosolvate], {[Ag(C15H15N3)2]ClO4·CH3OH}n, (II), are isostructural and exhibit one-dimensional ladder-like structures in which each asymmetric unit contains one metal ion (Cu+or Ag+), two 2-ethyl-1-(pyridin-3-ylmethyl)-1H-benzimidazole (bep) ligands, one counter-anion (tetrafluoroborate or perchlorate) and one interstitial molecule (acetonitrile or methanol). Each metal ion exhibits a distorted tetrahedral coordination geometry consisting of two pyridyl and two benzimidazole N atoms from four distinct ligands. Two metal ions are linked by two bep ligands to form a centrosymmetric 18-memberedM2(bep)2metallacycle, while adjacentM2(bep)2metallacycles are further interlinked by another two bep ligands resulting in a ladder-like array. In the extended structure, four adjacent ladder-like arrays are connected together through C—H...F, O—H...O and C—H...O hydrogen bonds between bep ligands, solvent molecules and counter-anions into a three-dimensional supramolecular structure.


2014 ◽  
Vol 70 (4) ◽  
pp. 359-363 ◽  
Author(s):  
Zouaoui Setifi ◽  
Fatima Setifi ◽  
Mohamed Saadi ◽  
Djamil-Azzeddine Rouag ◽  
Christopher Glidewell

In the title compound, [Cu(C2N3)2(C12H10N6)]nor [Cu(dca)2(abpt)]n, where abpt is 4-amino-3,5-bis(pyridin-2-yl)-4H-1,2,4-triazole and dca is the dicyanamide anion, the CuIIcentre is five-coordinate with an approximately square-pyramidal geometry. One of the two dicyanamide ligands is a terminal ligand, but the other one acts as a μ1,5-bridging ligand between pairs of CuIIcentres, so generating a one-dimensional coordination polymer. A combination of N—H...N and C—H...N hydrogen bonds, augmented by π–π stacking interactions, links the coordination polymer chains into a bilayer structure. Comparisons are made with some related CuIIcomplexes containing dca ligands and heteroaromatic co-ligands.


2012 ◽  
Vol 68 (8) ◽  
pp. m1131-m1131
Author(s):  
Jun Wang ◽  
Wubiao Zhu ◽  
Jichang Li

In the title one-dimensional coordination polymer, [Mn(NCS)3(C10H16N3)]n, the MnIIatom is coordinated by anN,N′-bidentate Schiff base and four thiocyanate ligands in a distorted octahedral N5S geometry. Bridging thiocyanate ligands interconnect adjacent [Mn(NCS)2(C10H16N3)] units, giving rise to helical chains extending along thebaxis. The chains are further linked through N—H...S hydrogen bonds, leading to a three-dimensional supramolecular network.


2013 ◽  
Vol 69 (10) ◽  
pp. 1140-1143 ◽  
Author(s):  
Masoud Mirzaei ◽  
Hossein Eshtiagh-Hosseini ◽  
Zahra Karrabi ◽  
Behrouz Notash

4-Hydroxypyridine-2,6-dicarboxylic acid (chelidamic acid, hypydc[H]H2) reacts with MnCl2·2H2O in the presence of piperazine in water to afford the title complex, {[Mn3(C7H2NO5)2(H2O)8]·3H2O}nor {[Mn3(hypydc)2(H2O)8]·3H2O}n. This compound is a one-dimensional coordination polymer, with the twofold symmetric repeat unit containing three metal centres. Two different coordination geometries are observed for the two independent MnIImetal centres,viz.a distorted pentagonal bipyramid and a distorted octahedron. The 4-oxidopyridine-2,6-dicarboxylate anions and two of the water molecules act as bridging ligands. The zigzag-like geometry of the coordination polymer is stabilized by hydrogen bonds. O—H...O and C—H...O hydrogen bonds and water clusters consolidate the three-dimensional network structure.


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