A Solvent Free Synthetic Route for Cerium(IV) Metal-Organic Frame-works with UiO-66 Architecture and Their Photocatalytic Application

<div> A novel solvent-free synthesis for Ce-UiO-66 metal-organic frameworks (MOFs) is presented. The MOFs are obtained by simply grinding the reagents, cerium ammonium nitrate (CAN) and the carboxylic linkers, in a mortar for few minutes with the addition of a small amount of acetic acid (AcOH) as modulator (1.75 eq, o.1 ml). The slurry is then transferred into a 1 ml vial and heated at 120°C for 1 day. The MOFs have been characterized for their composition, crystallinity and porosity and employed as heterogenous catalysts for the photo-oxidation reaction of substituted benzylic alcohols to benzaldaldehydes under near ultraviolet light irradiation. The catalytic performances, such as yield, conversion and kinetics, exceed those of similar systems studied by chemical oxidation and using Ce-MOF as catalyst. Moreover, the MOFs were found to be reusable up to three cycles without loss of activity. Density functional theory (DFT) calculations gave an estimation of the band-gap shift due to the different nature of the linkers used and provide useful information on the catalytic activity experimentally observed. </div>

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A Solvent Free Synthetic Route for Cerium(IV) Metal-Organic Frame-works with UiO-66 Architecture and Their Photocatalytic Application

10.26434/chemrxiv.9199634 ◽

2019 ◽

Author(s):

Matteo Campanelli ◽

Tiziana Del Giacco ◽

Filippo De Angelis ◽

Edoardo Mosconi ◽

Marco Taddei ◽

...

Keyword(s):

Density Functional ◽

Chemical Oxidation ◽

Solvent Free ◽

Cerium Ammonium Nitrate ◽

Benzylic Alcohols ◽

Near Ultraviolet ◽

Photocatalytic Application ◽

Activity Density ◽

Ultraviolet Light Irradiation ◽

Metal Organic

<div> A novel solvent-free synthesis for Ce-UiO-66 metal-organic frameworks (MOFs) is presented. The MOFs are obtained by simply grinding the reagents, cerium ammonium nitrate (CAN) and the carboxylic linkers, in a mortar for few minutes with the addition of a small amount of acetic acid (AcOH) as modulator (1.75 eq, o.1 ml). The slurry is then transferred into a 1 ml vial and heated at 120°C for 1 day. The MOFs have been characterized for their composition, crystallinity and porosity and employed as heterogenous catalysts for the photo-oxidation reaction of substituted benzylic alcohols to benzaldaldehydes under near ultraviolet light irradiation. The catalytic performances, such as yield, conversion and kinetics, exceed those of similar systems studied by chemical oxidation and using Ce-MOF as catalyst. Moreover, the MOFs were found to be reusable up to three cycles without loss of activity. Density functional theory (DFT) calculations gave an estimation of the band-gap shift due to the different nature of the linkers used and provide useful information on the catalytic activity experimentally observed. </div>

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Tuning the Redox Activity of Metal−Organic Frameworks for Enhanced, Selective O2 Binding

10.26434/chemrxiv.10316681.v1 ◽

2019 ◽

Author(s):

Andrew Rosen ◽

M. Rasel Mian ◽

Timur Islamoglu ◽

Haoyuan Chen ◽

Omar Farha ◽

...

Keyword(s):

Density Functional ◽

Metal Organic Frameworks ◽

Redox Activity ◽

Screening Methods ◽

Bridging Ligands ◽

Metal Centers ◽

Computational Screening ◽

Open Metal Sites ◽

Metal Organic ◽

Unsaturated Metal Sites

Metal−organic frameworks (MOFs) with coordinatively unsaturated metal sites are appealing as adsorbent materials due to their tunable functionality and ability to selectively bind small molecules. Through the use of computational screening methods based on periodic density functional theory, we investigate O2 and N2 adsorption at the coordinatively unsaturated metal sites of several MOF families. A variety of design handles are identified that can be used to modify the redox activity of the metal centers, including changing the functionalization of the linkers (replacing oxido donors with sulfido donors), anion exchange of bridging ligands (considering μ-Br-, μ-Cl-, μ-F-, μ-SH-, or μ-OH- groups), and altering the formal oxidation state of the metal. As a result, we show that it is possible to tune the O2 affinity at the open metal sites of MOFs for applications involving the strong and/or selective binding of O2. In contrast with O2 adsorption, N2 adsorption at open metal sites is predicted to be relatively weak across the MOF dataset, with the exception of MOFs containing synthetically elusive V2+ open metal sites. As one example from the screening study, we predict that exchanging the μ-Cl- ligands of M2Cl2(BBTA) (H2BBTA = 1H,5H-benzo(1,2-d:4,5-d′)bistriazole) with μ-OH- groups would significantly enhance the strength of O2 adsorption at the open metal sites without a corresponding increase in the N2 affinity. Experimental investigation of Co2Cl2(BBTA) and Co2(OH)2(BBTA) confirms that the former exhibits only weak physisorption, whereas the latter is capable of chemisorbing O2 at room temperature. The chemisorption behavior is attributed to the greater electron-donating character of the μ-OH- ligands and the presence of H-bonding interactions between the μ-OH- bridging ligands and the O2 adsorbate.

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Green Synthesis and Enhanced CO2 Capture Performance of Perfluorinated Cerium-Based Metal-Organic Frameworks with UiO-66 and MIL-140 Topology

10.26434/chemrxiv.6876749.v1 ◽

2018 ◽

Cited By ~ 1

Author(s):

Roberto D’Amato ◽

Anna Donnadio ◽

Mariolino Carta ◽

Claudio Sangregorio ◽

Riccardo Vivani ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Metal Organic Frameworks ◽

Isosteric Heat ◽

Experimental Conditions ◽

Cerium Ammonium Nitrate ◽

Ideal Adsorbed Solution Theory ◽

Metal Organic ◽

Adsorbed Solution ◽

Better Than ◽

The Ideal

Reaction of cerium ammonium nitrate and tetrafluoroterephthalic acid in water afforded two new metal-organic frameworks with UiO-66 [F4_UiO-66(Ce)] and MIL-140 [F4_MIL-140A(Ce)] topologies. The two compounds can be obtained in the same experimental conditions, just by varying the amount of acetic acid used as crystallization modulator in the synthesis. Both F4_UiO-66(Ce) and F4_MIL-140A(Ce) feature pores with size < 8 Å, which classifies them as ultramicroporous. Combination of X-ray photoelectron spectroscopy and magnetic susceptibility measurements revealed that both compounds contain a small amount of Ce(III), which is preferentially accumulated near the surface of the crystallites. The CO2 sorption properties of F4_UiO-66(Ce) and F4_MIL-140A(Ce) were investigated, finding that they perform better than their Zr-based analogues. F4_MIL-140A(Ce) displays an unusual S-shaped isotherm with steep uptake increase at pressure < 0.2 bar at 298 K. This makes F4_MIL-140A(Ce) exceptionally selective for CO2 over N2: the calculated selectivity, according to the ideal adsorbed solution theory for a 0.15:0.85 mixture at 1 bar and 293 K, is higher than 1900, amongst the highest ever reported for metal-organic frameworks. The calculated isosteric heat of CO2 adsorption is in the range of 38-40 kJ mol-1, indicating a strong physisorptive character.

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Density Functional Investigation of the Conversion of Furfural to Furfuryl Alcohol by Reaction with i-Propanol over UiO-66 Metal–Organic Framework

Inorganic Chemistry ◽

10.1021/acs.inorgchem.0c03764 ◽

2021 ◽

Author(s):

Jarinya Sittiwong ◽

Sininat Boonmark ◽

Watinee Nunthakitgoson ◽

Thana Maihom ◽

Chularat Wattanakit ◽

...

Keyword(s):

Furfuryl Alcohol ◽

Density Functional ◽

Metal Organic Framework ◽

Metal Organic ◽

Functional Investigation ◽

Organic Framework

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A direct solvent-free conversion approach to prepare mixed-metal metal–organic frameworks from doped metal oxides

Chemical Communications ◽

10.1039/d1cc00671a ◽

2021 ◽

Vol 57 (29) ◽

pp. 3587-3590

Author(s):

Beili Yi ◽

Haojie Zhao ◽

Yue Zhang ◽

Xiaomeng Si ◽

Guanqun Zhang ◽

...

Keyword(s):

Metal Oxides ◽

Metal Organic Frameworks ◽

Solvent Free ◽

Mixed Metal ◽

Synthesis Strategy ◽

Metal Metal ◽

Metal Organic

We propose a novel solvent-free conversion strategy of Pt–ZnO to Pt-ZIF-8. This synthesis strategy may facilitate the discovery of MMOFs that have not been reported previously.

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Selective capture of carbon dioxide from hydrocarbons using a metal-organic framework

Nature Communications ◽

10.1038/s41467-020-20489-2 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Omid T. Qazvini ◽

Ravichandar Babarao ◽

Shane G. Telfer

Keyword(s):

Carbon Dioxide ◽

Density Functional ◽

Metal Organic Framework ◽

Density Functional Theory Calculations ◽

Time Lags ◽

X Ray Crystallography ◽

Metal Organic ◽

Adsorption Of Co ◽

Short Time ◽

Organic Framework

AbstractEfficient and sustainable methods for carbon dioxide capture are highly sought after. Mature technologies involve chemical reactions that absorb CO2, but they have many drawbacks. Energy-efficient alternatives may be realised by porous physisorbents with void spaces that are complementary in size and electrostatic potential to molecular CO2. Here, we present a robust, recyclable and inexpensive adsorbent termed MUF-16. This metal-organic framework captures CO2 with a high affinity in its one-dimensional channels, as determined by adsorption isotherms, X-ray crystallography and density-functional theory calculations. Its low affinity for other competing gases delivers high selectivity for the adsorption of CO2 over methane, acetylene, ethylene, ethane, propylene and propane. For equimolar mixtures of CO2/CH4 and CO2/C2H2, the selectivity is 6690 and 510, respectively. Breakthrough gas separations under dynamic conditions benefit from short time lags in the elution of the weakly-adsorbed component to deliver high-purity hydrocarbon products, including pure methane and acetylene.

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