The properties of the bonding between CO and ZIF-8 structures: a density functional theory study

Wang, Haifeng; Zhao, Lianming; Xu, Wenbin; Wang, Shengping; Ding, Qiuyue; Lu, Xiaoqing; Guo, Wenyue

doi:10.1007/s00214-015-1636-4

Cited by 9 publications

(10 citation statements)

References 40 publications

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“…From a fundamental perspective, these characteristics are ruled by the electronic charge distribution in the material and the nature of the chemical bonds therein. Despite the general consensus regarding the ionic nature of the Zn–N bond in ZIFs, − the actual strength of this bond and the influence exerted on it by the chemical environment are still a matter of debate. ,, In particular, recent studies have unraveled nontrivial characteristics in the electronic structure of ZIF-8, − which point to the existence of some degree of covalence in the bond between Zn and N. This hypothesis is supported by ab initio calculations on the transport properties and by the vibrational activity of ZIFs. , Experimental evidence of the (partial) covalent character of Zn–N coordination is, to date, only indirect. Observations of chemical bond stability of ZIF-8 and related compounds especially in acidic environments point to their susceptibility to hydrolytic cleavage, which is only known for covalent bonds .…”

Section: Introductionmentioning

confidence: 98%

Effects of Ligand Substituents on the Character of Zn-Coordination in Zeolitic Imidazolate Frameworks

Edzards,

Saßnick,

Buzanich

et al. 2023

J. Phys. Chem. C

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Due to their favorable properties and high porosity, zeolitic imidazolate frameworks (ZIFs) have recently received much limelight for key technologies such as energy storage, optoelectronics, sensorics, and catalysis. Despite widespread interest in these materials, fundamental questions regarding the zinc coordination environment remain poorly understood. By focusing on zinc(II)2-methylimidazolate (ZIF-8) and its tetrahedrally coordinated analogues with Br-, Cl-, and H-substitution in the 2-ring position, we aim to clarify how variations in the local environment of Zn impact the charge distribution and the electronic properties of these materials. Our results from densityfunctional theory confirm the presence of a Zn coordinative bond with a large polarization that is quantitatively affected by different substituents on the organic ligand. Moreover, our findings suggest that the variations in the Zn coordination induced by the functionalization have a negligible effect on the electronic structure of the considered compounds. On the other hand, halogen terminations of the ligands lead to distinct electronic contributions in the vicinity of the frontier region which ultimately reduce the band gap size by a few hundred millielectron volts. Experimental results obtained from X-ray absorption spectroscopy (Zn K-edge) confirm the trends predicted by theory and, together with them, contribute to a better understanding of the structure−property relationships that are needed to tailor ZIFs for target applications.

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Section: Introductionmentioning

confidence: 98%

Effects of Ligand Substituents on the Character of Zn-Coordination in Zeolitic Imidazolate Frameworks

Edzards,

Saßnick,

Buzanich

et al. 2023

J. Phys. Chem. C

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“…ZIFs have been used as fillers in polymeric matrices in membrane technology due to its great potential for sorption, separation of mixtures of gases and vapors [10,11,12,13]. ZIF-8, which molecular formula is: Zn (mIm)2, (where mIm=2-methylimidazole) has sodalite topology and shows adsorption affinity CO2 molecules; also the ZIF-8 exhibits exceptional thermal and chemical stability [8,14,15]. ZIF-67, Co (mIm)2, ZIF-Mix, Zn/Co (mIm)2, and ZIF-8 are isostructural materials exhibit six members rings (~ 3.4 Å) as pore openings [16,17,18].…”

Section: Introductionmentioning

confidence: 99%

Modification of polyetherimide membranes with ZIFs fillers for CO2 separation

Vega

Andrio

Lemus

et al. 2019

Separation and Purification Technology

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Flat hybrid membranes composed of polyetherimide (PEI) as matrix and zeolitic imidazolate frameworks (ZIFs) as fillers at concentrations of 10 and 20 wt % were prepared. Apparent permeability coefficient and apparent diffusivity coefficient of gases (CO2 and N2) for these hybrid membranes (PZIFs) were determined by the "time-lag" method. The experimental conditions used were from 25 °C to 55 °C with pressures of 2, 3 and 5 bar. The PZIFs with fillers of ZIF-8 (PZ-Zn) and ZIF-67 (PZ-Co) showed apparent selectivities ( ( 2 ) ( 2 ) ⁄ ) of 39.6 and 27.5, respectively, higher than the( 2 ) ⁄ of the reference membrane PEI, while the membrane with filler of ZIF-Mix (PZ-Zn/Co) showed the lowest( 2 ) ⁄ selectivity of 10.3 in the membrane series (under conditions of 25 °C and 2 bar). It is proposed that the selectivity of the membrane series can be attributed to two critical factors: the particle size/distribution ratio in the polymer base and sorption of CO2 at local sites of the bimetallic mixture.On the other hand, gas permeation studies (O2, CO2 and CH4, and CO2/CH4 and CO2/C2H4 mixtures), were carried out in the series of PZIFs membranes. Permeability data were obtained by an isostatic method based on a permeation cell connected in series to a gas chromatograph where the rate of permeated gases was analyzed until a stationary state was reached. The complementary characterization techniques were: scanning electron microscopy, thermogravimetric analysis, and powder X-ray diffraction, which support the existence of the amorphous/crystalline phases of the PZIFs.

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“…In most post-modifications, only a local area can be functionalized without altering the original structural integrity [14][15]. The resulting heterogeneous regions, called defects, can significantly alter the material performance in some applications [9,14,[16][17].…”

Section: Introductionmentioning

confidence: 99%

“…Theoretical and computational methods can therefore more readily provide a microscopic understanding of the post-modification defect framework [18][19][20][21]. Density functional theory (DFT) calculations have, independent of force field parameters, contributed significantly to a better understanding of the post-modified framework structure [17,22]. Schmidt et al for example showed that post-modification via missing elementary linkers and metals in ZIFs impose only a small energy penalty, making their appearance thermodynamically unsurprising [22].…”

Section: Introductionmentioning

confidence: 99%

“…Schmidt et al for example showed that post-modification via missing elementary linkers and metals in ZIFs impose only a small energy penalty, making their appearance thermodynamically unsurprising [22]. In other work, post-modified ZIFs have been shown to exhibit strong Lewis acidity, having a potentially outsized impact on guest molecule adsorption and hence catalytic properties [17,22]. In a few limited examples, post-modification has been shown to alter gate size [16,23], an essential characteristic in guest transfer for chemical separation and drug delivery applications [24][25][26].…”

Section: Introductionmentioning

confidence: 99%

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ZIF-8 gate tuning via terminal group modification: A computational study

Zheng

Wang

et al. 2016

Chemical Physics Letters

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Tuning the pore structure of zeolitic imidazolate frameworks (ZIFs) enables unique control of their material properties. In this work, we used computational methods to examine the gate structure of ZIF-8 tuned by substitution terminal groups. The substitution position and electron affinity of the added groups were shown to be key factors in gate size. Electrostatic interactions are responsible for the variation in gate opening. These results suggest that the post-modification of terminal group in ZIFs can be used to finely tune the pore gate, opening up new strategies in the design of ZIFs with desired properties. Highlights 1. The substitution position of the added groups tunes the ZIF-8 gate via steric effect.2. The electron affinity of the terminal group can be used to finely control the ZIF-8 gate.3. Electrostatic interactions between linkers comprising the tetrahedron geometry of Zn(IM) 4 are responsible for the variation in ZIF-8 gate opening.

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The properties of the bonding between CO and ZIF-8 structures: a density functional theory study

Cited by 9 publications

References 40 publications

Effects of Ligand Substituents on the Character of Zn-Coordination in Zeolitic Imidazolate Frameworks

Effects of Ligand Substituents on the Character of Zn-Coordination in Zeolitic Imidazolate Frameworks

Modification of polyetherimide membranes with ZIFs fillers for CO2 separation

ZIF-8 gate tuning via terminal group modification: A computational study

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