Selective, High-Temperature O2 Adsorption in Chemically Reduced, Redox-Active Iron-Pyrazolate Metal–Organic Frameworks

Developing O2-selective adsorbents that can produce high-purity oxygen from air remains a significant challenge. Here, we show that chemically reduced metal–organic framework materials of the type AxFe2(bdp)3 (A = Na+, K+; bdp2− = 1,4-benzenedipyrazolate; 0 < x ≤ 2), which feature coordinatively saturated iron centers, are capable of strong and selective adsorption of O2 over N2 at ambient (25 °C) or even elevated (200 °C) temperature. A combination of gas adsorption analysis, single-crystal X-ray diffraction, magnetic susceptibility measurements, and a range of spectroscopic methods, including 23Na solid-state NMR, Mössbauer, and X-ray photoelectron spectroscopies, are employed as probes of O2 uptake. Significantly, the results support a selective adsorption mechanism involving outer-sphere electron transfer from the framework to form superoxide species, which are subsequently stabilized by intercalated alkali metal cations that reside in the one-dimensional triangular pores of the structure. We further demonstrate similar O2 uptake behavior to that of AxFe2(bdp)3 in an expanded-pore framework analogue and thereby gain additional insight into the O2 adsorption mechanism. The chemical reduction of a robust metal–organic framework to render it capable of binding O2 through such an outer-sphere electron transfer mechanism represents a promising and underexplored strategy for the design of next-generation O2 adsorbents.

Download Full-text

Selective, High-Temperature O2 Adsorption in Chemically Reduced, Redox-Active Iron-Pyrazolate Metal–Organic Frameworks

10.26434/chemrxiv.9922541.v4 ◽

2020 ◽

Author(s):

Adam Jaffe ◽

Michael Ziebel ◽

David M. Halat ◽

Naomi Biggins ◽

Ryan Murphy ◽

...

Keyword(s):

Electron Transfer ◽

Adsorption Mechanism ◽

Selective Adsorption ◽

Metal Organic Framework ◽

Outer Sphere ◽

Electron Transfer Mechanism ◽

X Ray ◽

Metal Organic ◽

Outer Sphere Electron Transfer ◽

Organic Framework

Developing O2-selective adsorbents that can produce high-purity oxygen from air remains a significant challenge. Here, we show that chemically reduced metal–organic framework materials of the type AxFe2(bdp)3 (A = Na+, K+; bdp2− = 1,4-benzenedipyrazolate; 0 < x ≤ 2), which feature coordinatively saturated iron centers, are capable of strong and selective adsorption of O2 over N2 at ambient (25 °C) or even elevated (200 °C) temperature. A combination of gas adsorption analysis, single-crystal X-ray diffraction, magnetic susceptibility measurements, and a range of spectroscopic methods, including 23Na solid-state NMR, Mössbauer, and X-ray photoelectron spectroscopies, are employed as probes of O2 uptake. Significantly, the results support a selective adsorption mechanism involving outer-sphere electron transfer from the framework to form superoxide species, which are subsequently stabilized by intercalated alkali metal cations that reside in the one-dimensional triangular pores of the structure. We further demonstrate similar O2 uptake behavior to that of AxFe2(bdp)3 in an expanded-pore framework analogue and thereby gain additional insight into the O2 adsorption mechanism. The chemical reduction of a robust metal–organic framework to render it capable of binding O2 through such an outer-sphere electron transfer mechanism represents a promising and underexplored strategy for the design of next-generation O2 adsorbents.

Download Full-text

Selective, High-Temperature O2 Adsorption in Chemically Reduced, Redox-Active Iron-Pyrazolate Metal–Organic Frameworks

10.26434/chemrxiv.9922541.v2 ◽

2019 ◽

Cited By ~ 1

Author(s):

Adam Jaffe ◽

Michael Ziebel ◽

David M. Halat ◽

Naomi Biggins ◽

Ryan Murphy ◽

...

Keyword(s):

Electron Transfer ◽

Photoelectron Spectroscopy ◽

Chemical Reduction ◽

Metal Organic Framework ◽

Outer Sphere ◽

Electron Transfer Mechanism ◽

X Ray ◽

Metal Organic ◽

Outer Sphere Electron Transfer ◽

Organic Framework

Developing O2-selective adsorbents that can produce high-purity oxygen from air remains a significant challenge. Here, we show that the chemically reduced metal–organic framework AxFe2(BDP)3 (A = Na+, K+; BDP2− = 1,4-benzenedipyrazolate; 0 < x ≤ 2), which features coordinatively-saturated iron centers, is capable of strong and selective adsorption of O2 over N2 at ambient (25 °C) or even elevated (200 °C) temperature. Through a combination of gas adsorption measurements, single-crystal X-ray diffraction, and numerous spectroscopic probes, including 23Na solid-state NMR and X-ray photoelectron spectroscopy, we demonstrate that selective O2 uptake likely occurs as a result of outer-sphere electron transfer from the framework to form superoxide species, which are subsequently stabilized by intercalated alkali metal cations that reside in the one-dimensional triangular pores of the framework. The chemical reduction of a robust metal–organic framework to render it capable of binding O2 through an outer-sphere electron transfer mechanism thus represents a promising and underexplored strategy for the design of next-generation O2 adsorbents.

Download Full-text

Selective, High-Temperature O2 Adsorption in Chemically Reduced, Redox-Active Iron-Pyrazolate Metal–Organic Frameworks

10.26434/chemrxiv.9922541.v1 ◽

2019 ◽

Author(s):

Adam Jaffe ◽

Michael Ziebel ◽

David M. Halat ◽

Naomi Biggins ◽

Ryan Murphy ◽

...

Keyword(s):

Electron Transfer ◽

Photoelectron Spectroscopy ◽

Chemical Reduction ◽

Metal Organic Framework ◽

Outer Sphere ◽

Electron Transfer Mechanism ◽

X Ray ◽

Metal Organic ◽

Outer Sphere Electron Transfer ◽

Organic Framework

Developing O2-selective adsorbents that can produce high-purity oxygen from air remains a significant challenge. Here, we show that the chemically reduced metal–organic framework AxFe2(BDP)3 (A = Na+, K+; BDP2− = 1,4-benzenedipyrazolate; 0 < x ≤ 2), which features coordinatively-saturated iron centers, is capable of strong and selective adsorption of O2 over N2 at ambient (25 °C) or even elevated (200 °C) temperature. Through a combination of gas adsorption measurements, single-crystal X-ray diffraction, and numerous spectroscopic probes, including 23Na solid-state NMR and X-ray photoelectron spectroscopy, we demonstrate that selective O2 uptake likely occurs as a result of outer-sphere electron transfer from the framework to form superoxide species, which are subsequently stabilized by intercalated alkali metal cations that reside in the one-dimensional triangular pores of the framework. The chemical reduction of a robust metal–organic framework to render it capable of binding O2 through an outer-sphere electron transfer mechanism thus represents a promising and underexplored strategy for the design of next-generation O2 adsorbents.

Download Full-text

Imidazole-containing Cd Metal-Organic Framework with Selective Adsorption Properties

E3S Web of Conferences ◽

10.1051/e3sconf/201911801044 ◽

2019 ◽

Vol 118 ◽

pp. 01044

Author(s):

Yu-Ling Li ◽

Zin Zheng ◽

Hui Nie ◽

Chun-Mei Zhao ◽

Yu-Fei Wang ◽

...

Keyword(s):

Hydrogen Bonds ◽

Selective Adsorption ◽

Metal Organic Framework ◽

Chain Structure ◽

Adsorption Properties ◽

X Ray Diffraction ◽

X Ray ◽

1D Chain ◽

Metal Organic ◽

Organic Framework

Metal-organic framework material [Cd(tib)(dnbpdc) (H2O)]·2DMF·2H2O (1) [tib = 1, 3, 5-tris(1-imidazolyl)benzene, H2dnbpdc = 2, 2′-dinitro-4, 4′-biphenyldicarboxylic acid] was synthesized and characterized by Thermogravimetric analyses (TGA), Powder X-ray diffraction (PXRD) analyses and Bruker D8 Advance X-ray diffractometer. The results showed that 1 was a 1D chain structure to be joined together by hydrogen bonds to generate a 3D supramolecular structure. CO2 and N2 adsorption behavior of the material was studied. It is significative that 1 can selective sorption of CO2.

Download Full-text

Understanding the Adsorption Mechanism of Xe and Kr in a Metal–Organic Framework from X-ray Structural Analysis and First-Principles Calculations

The Journal of Physical Chemistry Letters ◽

10.1021/acs.jpclett.5b00440 ◽

2015 ◽

Vol 6 (10) ◽

pp. 1790-1794 ◽

Cited By ~ 29

Author(s):

Sanjit K. Ghose ◽

Yan Li ◽

Andrey Yakovenko ◽

Eric Dooryhee ◽

Lars Ehm ◽

...

Keyword(s):

Structural Analysis ◽

First Principles ◽

Adsorption Mechanism ◽

Metal Organic Framework ◽

First Principles Calculations ◽

X Ray ◽

Metal Organic ◽

Organic Framework

Download Full-text

A fourfold interpenetrating cadmium(II) metal–organic framework based on 2,4,6-tris(pyridin-4-yl)-1,3,5-triazine with reversible photochromic properties

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s2053229619002663 ◽

2019 ◽

Vol 75 (3) ◽

pp. 372-377 ◽

Cited By ~ 1

Author(s):

Jian-Jun Liu ◽

Li-Zhi Li ◽

Chun-Ping Chen ◽

Jin-Zhong Wei ◽

Fei-Xiang Cheng

Keyword(s):

Electron Transfer ◽

Photoinduced Electron Transfer ◽

Metal Organic Framework ◽

Crystal Structure Analysis ◽

X Ray Diffraction ◽

Photochromic Properties ◽

X Ray ◽

Good Thermal Stability ◽

Metal Organic ◽

Organic Framework

2,4,6-Tris(pyridin-4-yl)-1,3,5-triazine (tpt), as an organic molecule with an electron-deficient nature, has attracted considerable interest because of its photoinduced electron transfer from neutral organic molecules to form stable anionic radicals. This makes it an excellent candidate as an organic linker in the construction of photochromic complexes. Such a photochromic three-dimensional (3D) metal–organic framework (MOF) has been prepared using this ligand. Crystallization of tpt with Cd(NO3)2·4H2O in an N,N-dimethylacetamide–methanol mixed-solvent system under solvothermal conditions afforded the 3D MOF poly[[bis(nitrato-κ2 O,O′)cadmium(II)]-μ3-2,4,6-tris(pyridin-4-yl)-1,3,5-triazine-κ3 N 2:N 4:N 6], [Cd(NO3)2(C18H12N6)] n , which was characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis and single-crystal X-ray diffraction. The X-ray diffraction crystal structure analysis reveals that the asymmetric unit contains one independent CdII cation, one tpt ligand and two coordinated NO3 − anions. The CdII cations are connected by tpt ligands to generate a 3D framework. The single framework leaves voids that are filled by mutual interpenetration of three independent equivalent frameworks in a fourfold interpenetrating architecture. The compound shows a good thermal stability and exhibits a reversible photochromic behaviour, which may originate from the photoinduced electron-transfer generation of radicals in the tpt ligand.

Download Full-text

Synthesis, structure and selective adsorption property of Zn metal-organic framework

E3S Web of Conferences ◽

10.1051/e3sconf/20185301034 ◽

2018 ◽

Vol 53 ◽

pp. 01034 ◽

Cited By ~ 1

Author(s):

Yu-Ling Li ◽

Yu-Fei Wang ◽

Li-Ping Zheng ◽

Xiao-Li Zhou ◽

Jing-Jing Li

Keyword(s):

Hydrogen Bonds ◽

Supramolecular Structure ◽

Selective Adsorption ◽

Adsorption Property ◽

Metal Organic Framework ◽

X Ray Diffraction ◽

X Ray ◽

Metal Organic ◽

2D Network ◽

Organic Framework

Zn metal-organic framework material [Zn2(tib)(HBTB)2(H2O)]·2H2O (1) [tib = 1,3,5-tris(1- imidazolyl)benzene, H3BTB = 4,4′,4″-benzene-1,3,5-triyl-tribenzoic acid] was synthesized and characterized by Thermogravimetric analyses (TGA), Powder X-ray diffraction (PXRD) analyses and Bruker D8 Advance X-ray diffractometer. The results showed that 1 was a 2D network to be joined together by hydrogen bonds to generate a 3D supramolecular structure. Gas, vapor adsorption behavior of the material was studied. It is meaningful that 1 can selective sorption of CO2 and MeOH.

Download Full-text

Synthesis and Structure of a Clathrated Two-Dimensional Metal-Organic Framework: [Cd(4,4'-bpy)2(H2O)2](ClO4)2·(L)2·H2O (L = Bis(1-pyrazinylethylidene)hydrazine)

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20080024 ◽

2008 ◽

Vol 73 (1) ◽

pp. 24-31

Author(s):

Dayu Wu ◽

Genhua Wu ◽

Wei Huang ◽

Zhuqing Wang

Keyword(s):

Metal Organic Framework ◽

Channel Structure ◽

Two Dimensional ◽

X Ray Diffraction ◽

Guest Molecules ◽

X Ray ◽

Square Planar ◽

Metal Organic ◽

Aqueous Meoh ◽

Organic Framework

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.

Download Full-text

Backbonding contributions to small molecule chemisorption in a metal–organic framework with open copper(i) centers

Chemical Science ◽

10.1039/d0sc06038k ◽

2021 ◽

Author(s):

Gregory M. Su ◽

Han Wang ◽

Brandon R. Barnett ◽

Jeffrey R. Long ◽

David Prendergast ◽

...

Keyword(s):

Fine Structure ◽

Small Molecule ◽

Metal Organic Framework ◽

X Ray ◽

Metal Site ◽

Absorption Fine ◽

Metal Organic ◽

X Ray Absorption ◽

Organic Framework

In situ near edge X-ray absorption fine structure spectroscopy directly probes unoccupied states associated with backbonding interactions between the open metal site in a metal–organic framework and various small molecule guests.

Download Full-text