scholarly journals Spin Crossover Metal-Organic Frameworks with Inserted Photoactive Guests: On the Quest to Control the Spin State by Photoisomerization

2021 ◽  
Author(s):  
Barbora Brachnakova ◽  
Jan Moncol ◽  
Jan Pavlik ◽  
Ivan Salitros ◽  
Sébastien Bonhommeau ◽  
...  

Three Hofmann-like metal-organic frameworks {Fe(bpac)[Pt(CN)4]}·G (bpac=1,2-bis(4-pyridyl)acetylene) were synthesized with photoisomerizable guest molecules (G = trans-azobenzene, trans-stilbene or cis-stilbene) and were characterized by elemental analysis, thermogravimetry and powder X-ray diffraction. The...

2021 ◽  
Vol 47 (9) ◽  
pp. 593-600
Author(s):  
A. A. Lysova ◽  
V. A. Dubskikh ◽  
K. D. Abasheeva ◽  
A. A. Vasileva ◽  
D. G. Samsonenko ◽  
...  

Abstract Three new metal−organic frameworks based on scandium(III) cations and 2,5-thiophenedicarboxylic acid (H2Tdc) are synthesized: [Sc(Tdc)(OH)]·1.2DMF (I), [Sc(Tdc)(OH)]·2/3DMF (II), and (Me2NH2)[Sc3(Tdc)4(OH)2]·DMF (III) (DMF is N,N-dimethylformamide). The structures of the compounds are determined by single-crystal X-ray structure analysis (CIF file CCDC nos. 2067819 (I), 2067820 (II), and 2067821 (III)). The chemical and phase purity of compound I is proved by elemental analysis, thermogravimetry, X-ray diffraction analysis, and IR spectroscopy.


2014 ◽  
Vol 14 (11) ◽  
pp. 5397-5407 ◽  
Author(s):  
Andrey A. Yakovenko ◽  
Zhangwen Wei ◽  
Mario Wriedt ◽  
Jian-Rong Li ◽  
Gregory J. Halder ◽  
...  

2018 ◽  
Author(s):  
C. Huy Pham ◽  
Francesco Paesani

<div> <div> <div> <p>Computer simulations are carried out to characterize the variation of spin crossover (SCO) behavior of the prototypical {Fe(pz)[Pt(CN)4]} metal-organic framework (MOF) upon adsorption of chemically and structurally different guest molecules. A detailed analysis of both strength and anisotropy of guest molecule-framework interactions reveals direct correlations between the mobility of the guest molecules inside the MOF pores, the rotational mobility of the pyrazine rings of the framework, and the stabilization of the low-spin state of the material. Based on these correlations, precise molecular criteria are established for predicting the spin state of {Fe(pz)[Pt(CN)4]} upon guest adsorption. Finally, predictions of the SCO temperature upon adsorption of various toxic gases demonstrate that in silico modeling can provide fundamental insights and design principles for the development of spin-crossover MOFs for applications in gas detection and chemical sensing. </p> </div> </div> </div>


2018 ◽  
Author(s):  
C. Huy Pham ◽  
Francesco Paesani

<div> <div> <div> <p>Computer simulations are carried out to characterize the variation of spin crossover (SCO) behavior of the prototypical {Fe(pz)[Pt(CN)4]} metal-organic framework (MOF) upon adsorption of chemically and structurally different guest molecules. A detailed analysis of both strength and anisotropy of guest molecule-framework interactions reveals direct correlations between the mobility of the guest molecules inside the MOF pores, the rotational mobility of the pyrazine rings of the framework, and the stabilization of the low-spin state of the material. Based on these correlations, precise molecular criteria are established for predicting the spin state of {Fe(pz)[Pt(CN)4]} upon guest adsorption. Finally, predictions of the SCO temperature upon adsorption of various toxic gases demonstrate that in silico modeling can provide fundamental insights and design principles for the development of spin-crossover MOFs for applications in gas detection and chemical sensing. </p> </div> </div> </div>


2008 ◽  
Vol 73 (1) ◽  
pp. 24-31
Author(s):  
Dayu Wu ◽  
Genhua Wu ◽  
Wei Huang ◽  
Zhuqing Wang

The compound [Cd(4,4'-bpy)2(H2O)2](ClO4)2·(L)2 was obtained by the reaction of Cd(ClO4)2, bis(1-pyrazinylethylidene)hydrazine (L) and 4,4'-bipyridine in aqueous MeOH. Single-crystal X-ray diffraction has revealed its two-dimensional metal-organic framework. The 2-D layers superpose on each other, giving a channel structure. The square planar grids consist of two pairs of shared edges with Cd(II) ion and a 4,4'-bipyridine molecule each vertex and side, respectively. The square cavity has a dimension of 11.817 × 11.781 Å. Two guest molecules of bis(1-pyrazinylethylidene)hydrazine are clathrated in every hydrophobic host cavity, being further stabilized by π-π stacking and hydrogen bonding. The results suggest that the hydrazine molecules present in the network serve as structure-directing templates in the formation of crystal structures.


2020 ◽  
Vol 75 (8) ◽  
pp. 727-732
Author(s):  
Chen Zhang ◽  
Jian-Qing Tao

AbstractA new Cu(II) metal-organic framework, [Cu(L)(OBA)·H2O]n (1) [H2OBA = 4,4′-oxybis(benzoic acid), L = 3,5-di(1H-benzimidazol-1-yl)pyridine] was hydrothermally synthesized and characterized through IR spectroscopy, elemental and thermal analysis and single-crystal X-ray diffraction. Complex 1 is a four-connected uni-nodal 2D net with a (44·62) topology which shows an emission centered at λ ∼393 nm upon excitation at λ = 245 nm. Moreover, complex 1 possesses high photocatalytic activities for the decomposition of Rhodamine B (RhB) under UV light irradiation.


Author(s):  
Stephen J. I. Shearan ◽  
Jannick Jacobsen ◽  
Ferdinando Costantino ◽  
Roberto D’Amato ◽  
Dmitri Novikov ◽  
...  

2021 ◽  
Author(s):  
Qing-Xia Yao ◽  
Miaomiao Tian ◽  
Jun Zheng ◽  
Jintang Xue ◽  
Xuze Pan ◽  
...  

A series of microporous Ln(III)-based metal-organic frameworks (1-Ln) have been hydrothermally synthesized by using 4,4',4''-nitrilotribenzoic acid (H3NTB). Single crystal X-ray diffraction analyses show 1-Ln are isostructural and have 3D porous...


2014 ◽  
Vol 70 (a1) ◽  
pp. C157-C157
Author(s):  
Claire Hobday ◽  
Stephen Moggach ◽  
Carole Morrison ◽  
Tina Duren ◽  
Ross Forgan

Metal-organic frameworks (MOFs) are a well-studied class of porous materials with the potential to be used in many applications such as gas storage and catalysis.[1] UiO-67 (UiO = University of Oslo), a MOF built from zirconium oxide units connected with 4,4-biphenyldicarboxylate (BDC) linkers, forms a face centred cubic structure. Zirconium has a high affinity towards oxygen ligands making these bridges very strong, resulting in UiO-based MOFs having high chemical and thermal stability compared to other MOF structures. Moreover, UiO-67 has become popular in engineering studies due to its high mechanical stability.[2] Using high pressure x-ray crystallography we can exert MOFs to GPa pressures, experimentally exploring the mechanical stability of MOFs to external pressure. By immersing the crystal in a hydrostatic medium, pressure is applied evenly to the crystal. On surrounding a porous MOF with a hydrostatic medium composed of small molecules (e.g. methanol), the medium can penetrate the MOF, resulting in medium-dependant compression. On compressing MOF-5 (Zn4O(BDC)3) using diethylformamide as a penetrating medium, the framework was shown to have an increased resistance to compression, becoming amorphous several orders of magnitude higher in pressure than observed on grinding the sample.[3] Here we present a high-pressure x-ray diffraction study on the UiO-based MOF UiO-67, and several new synthesised derivatives built from same metal node but with altered organic linkers, allowing us to study in a systematic way, the mechanical stability of the MOF, and its pressure dependence on both the linker, and pressure medium.


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.


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