Water Adsorption on Coordinatively Unsaturated Sites in CuBTC MOF

Grajciar, Lukáš; Bludský, Ota; Nachtigall, Petr

doi:10.1021/jz101378z

Cited by 180 publications

(242 citation statements)

References 41 publications

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“…This cluster was found to provide identical results to those obtained with much larger cluster models. 103 It was found that the combination of the predicted interaction enthalpies in very good agreement with the benchmark result calculated by Grajciar et al 101 The water to Cu and the Cu-Cu distances are quite different from functional to functional. The fact that the M06-2X yields almost as good results as the M06-L or M06 functionals is surprising since the latter were suggested to be better than the former for systems containing transition metal elements.…”

Section: Molecular Adsorptionsupporting

confidence: 71%

“…It was found that standard DFT methods are inadequate for describing the interaction of organic molecules with those metal sites very probably due to difficulties in the correct description of the dispersion interactions between the adsorbate and the MOF organic parts. In fact, in recent studies by Grajciar et al 101 it was found that BLYP, PBE, TPSS and B3LYP underestimate significantly the interaction energies for water with HKUST-1, a MOF with copper open metal sites based on copper ''paddle-wheels'' connected by benzene 1,3-5-tricarboxylate linkers (Fig. 11).…”

Section: Molecular Adsorptionmentioning

confidence: 98%

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Accounting for van der Waals interactions between adsorbates and surfaces in density functional theory based calculations: selected examples

2013

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This article reviews the different density functional theory (DFT) methods available in the literature for dealing with dispersion interactions and recent applications of DFT approaches including van der Waals corrections in the study of the interaction of atoms and molecules with several different surfaces. Focus is given to the interaction of atoms and molecules with metal, metal oxide and graphite surfaces or more complex systems. It will be shown that DFT approaches including van der Waals corrections present significant advances over standard exchange correlation functionals for treating systems dominated by weak interactions.

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Section: Molecular Adsorptionsupporting

confidence: 71%

Section: Molecular Adsorptionmentioning

confidence: 98%

Accounting for van der Waals interactions between adsorbates and surfaces in density functional theory based calculations: selected examples

2013

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“…The transition states from the extended cluster calculations were taken as starting geometries to find the transition states in the periodic model. An optimized Cu-BTC unit-cell was obtained from Nachtigall et al [61] and was reoptimized with periodic DFT-D2 calculations. For those simulations, the Brillouin zone was restricted to the Г-point.…”

Section: Periodic Calculationsmentioning

confidence: 99%

Insight in the activity and diastereoselectivity of various Lewis acid catalysts for the citronellal cyclization

Vandichel

Vermoortele

Cottenie

et al. 2013

Journal of Catalysis

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RECEIVED DATE (to be automatically inserted after your manuscript is accepted if required according to the journal that you are submitting your paper to) TITLE RUNNING HEAD Kinetics of the Lewis acid catalyzed citronellal cyclization 2 ABSTRACT Industrial (-)-menthol production generally relies on the hydrogenation of (-)-isopulegol, which is in turn produced with high selectivity by cyclization of (+)-citronellal. This paper uses a combined theoretical and experimental approach to study the activity and selectivity of three Lewis acid catalysts for this reaction, namely ZnBr 2 , aluminum tris(2,6-diphenylphenoxide) (ATPH) and the heterogeneous metal-organic framework Cu 3 BTC 2 (BTC = benzene-1,3,5-tricarboxylate). ATPH is a strong Lewis acid homogeneous catalyst with bulky ligands which provides very high selectivities for the desired stereoisomer (> 99 %). The performance of the catalysts was evaluated as a function of temperature, which revealed that higher catalyst activity allows working at lower temperatures and improves the selectivity for isopulegol. The selectivity distribution is kinetically driven for ZnBr 2 and ATPH. The theoretical selectivity distributions rely on the determination of an extensive set of diastereomeric transition states, for which the differences in free energy have been calculated using a complementary set of ab initio techniques. Given the sensitivity of the selectivity to small Gibbs free energy differences, the agreement between experimental and theoretical selectivities is satisfactory. On basis of the obtained insights rational design of new catalysts may be obtained. As proof of concept, the hypothetical Cu 3 (BTC-(NO 2 ) 3 ) 2 Lewis catalyst -in which each phenyl hydrogen of the BTC ligand is replaced by a nitro group -is predicted to be very selective.

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“…The separation of flue gas, however, requires thermodynamic information (for example, adsorption isotherms) at flue-gas conditions (40 8C and 1 atm). This type of information can be obtained from molecular simulation using classical force fields.For some classes of MOFs these predictions still pose significant difficulties, namely for MOFs with unsaturated-referred to as 'open'-metal sites [8][9][10][11][12][13][14][15] . These materials crystallize in such a way that both linkers and solvent molecules coordinate to the metal centres.…”

mentioning

confidence: 99%

“…The reason is that an open metal site imposes a chemical environment very different from those considered in the development of these force fields. 12 Ideally, we would use state-of-the-art quantum chemical calculations to evaluate the energy for each state point of a grand canonical Monte Carlo (GCMC) simulation to compute the adsorption isotherm. However, such calculations would require millions of years of central processing unit time.…”

mentioning

confidence: 99%

Ab initio carbon capture in open-site metal–organic frameworks

et al. 2012

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During the formation of metal-organic frameworks (MOFs), metal centres can coordinate with the intended organic linkers, but also with solvent molecules. In this case, subsequent activation by removal of the solvent molecules creates unsaturated 'open' metal sites known to have a strong affinity for CO 2 molecules, but their interactions are still poorly understood. Common force fields typically underestimate by as much as two orders of magnitude the adsorption of CO 2 in open-site Mg-MOF-74, which has emerged as a promising MOF for CO 2 capture. Here we present a systematic procedure to generate force fields using high-level quantum chemical calculations. Monte Carlo simulations based on an ab initio force field generated for CO 2 in Mg-MOF-74 shed some light on the interpretation of thermodynamic data from flue gas in this material. The force field describes accurately the chemistry of the open metal sites, and is transferable to other structures. This approach may serve in molecular simulations in general and in the study of fluid-solid interactions. Most energy scenarios project a significant increase in the role of renewable energy sources 1 . These scenarios also predict an even higher increase in our energy needs. As a consequence, although the relative consumption of fossil fuels will be decreasing, in absolute terms we will continue to burn more coal. In such a scenario, carbon capture and sequestration will be one of the only viable technologies to mitigate CO 2 emissions 1,2 . At present the cost associated with the capture of CO 2 from flue gas is one of the bottlenecks in the large-scale deployment of this technology. Of particular concern is that the efficiency of a coal-fired power plant decreases by as much as 30-40% (ref. 3) because of the energy required to separate and compress CO 2 . The aim of decreasing this parasitic load has motivated the search for novel materials 4,5 .A promising class of materials is metal-organic frameworks (MOFs) 4,6 . MOFs are crystalline materials that consist of metal centres connected by organic linkers. These materials have an extremely large internal surface area and, compared to other common adsorbents, promise very specific customization of their chemistry. By changing the metal and the linker, one can in principle generate many millions of possible materials. In practice, however, we can synthesize only a very small fraction of these materials, and it is important to develop a theoretical method that supports the experimental efforts to identify an ideal MOF for carbon capture. A key aspect is the ability to predict the properties of a MOF before the material is synthesized. At present it is possible to carry out accurate quantum chemical calculations on these types of systems 7 . State-of-the-art density functional theory (DFT) calculations provide important insights into the energetics and siting of CO 2 at zero Kelvin 7 . The separation of flue gas, however, requires thermodynamic information (for example, adsorption isotherms) at flue-gas conditions (40...

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Water Adsorption on Coordinatively Unsaturated Sites in CuBTC MOF

Cited by 180 publications

References 41 publications

Accounting for van der Waals interactions between adsorbates and surfaces in density functional theory based calculations: selected examples

Accounting for van der Waals interactions between adsorbates and surfaces in density functional theory based calculations: selected examples

Insight in the activity and diastereoselectivity of various Lewis acid catalysts for the citronellal cyclization

Ab initio carbon capture in open-site metal–organic frameworks

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