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Title: Topological analysis of void space in phosphate frameworks: Assessing storage properties for the environmentally important guest molecules and ions: CO 2, H 2O, UO 2, PuO 2, U, Pu, Sr 2+, Cs +, CH 4, and H 2

Abstract

The entrapment of environmentally important materials to enable containment of polluting wastes from industry or energy production, storage of alternative fuels, or water sanitation, is of vital and immediate importance. Many of these materials are small molecules or ions that can be encapsulated via their adsorption into framework structures to create a host-guest complex. This is an ever-growing field of study and, as such, the search for more suitable porous materials for environmental applications is fundamental to progress. However, many industrial areas that require the use of adsorbents are fraught with practical challenges such as high temperatures, rapid gas expansion, radioactivity, or repetitive gas cycling, that the host material must withstand. Inorganic phosphates have a proven history of rigid structures, thermal stability, and are suspected to possess good resistance to radiation over geologic time scales. Furthermore, various experimental studies have established their ability to adsorb small molecules, such as water. In light of this, all known crystal structures of phosphate frameworks with meta- (P 3O 9) or ultra- (P 5O 14) stoichiometries are combined in a data-mining survey together with all theoretically possible structures of Ln aP bO c (where a, b, c are any integer, and Ln = La,more » Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, or Tm) that are statistically likely to form. Topological patterns within these framework structures are used to assess their suitability for hosting a variety of small guest molecules or ions that are important for environmental applications: CO 2, H 2O, UO 2, PuO 2, U, Pu, Sr 2+, Cs +, CH 4 and H 2. A range of viable phosphate-based host-guest complexes are identified from this data-mining and pattern-based structural analysis. Moreover, distinct topological preferences for hosting such guests are found, and metaphosphate stoichiometries are generally preferred over ultraphosphate configurations.« less

Authors:
 [1];  [2]
  1. Univ. of Cambridge (United Kingdom)
  2. Univ. of Cambridge (United Kingdom); STFC Rutherford Appleton Lab., Harwell Science and Innovation Campus, Oxfordshire (United Kingdom); Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1333909
Grant/Contract Number:
AC02-06CH11357
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
ACS Sustainable Chemistry & Engineering
Additional Journal Information:
Journal Volume: 4; Journal Issue: 8; Journal ID: ISSN 2168-0485
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; CO2 emissions; energy fuel storage; host-guest structure; nuclear waste storage; phosphate; water sanitation

Citation Formats

Cramer, Alisha J., and Cole, Jacqueline M. Topological analysis of void space in phosphate frameworks: Assessing storage properties for the environmentally important guest molecules and ions: CO2, H2O, UO2, PuO2, U, Pu, Sr2+, Cs+, CH4, and H2. United States: N. p., 2016. Web. doi:10.1021/acssuschemeng.6b00316.
Cramer, Alisha J., & Cole, Jacqueline M. Topological analysis of void space in phosphate frameworks: Assessing storage properties for the environmentally important guest molecules and ions: CO2, H2O, UO2, PuO2, U, Pu, Sr2+, Cs+, CH4, and H2. United States. doi:10.1021/acssuschemeng.6b00316.
Cramer, Alisha J., and Cole, Jacqueline M. 2016. "Topological analysis of void space in phosphate frameworks: Assessing storage properties for the environmentally important guest molecules and ions: CO2, H2O, UO2, PuO2, U, Pu, Sr2+, Cs+, CH4, and H2". United States. doi:10.1021/acssuschemeng.6b00316. https://www.osti.gov/servlets/purl/1333909.
@article{osti_1333909,
title = {Topological analysis of void space in phosphate frameworks: Assessing storage properties for the environmentally important guest molecules and ions: CO2, H2O, UO2, PuO2, U, Pu, Sr2+, Cs+, CH4, and H2},
author = {Cramer, Alisha J. and Cole, Jacqueline M.},
abstractNote = {The entrapment of environmentally important materials to enable containment of polluting wastes from industry or energy production, storage of alternative fuels, or water sanitation, is of vital and immediate importance. Many of these materials are small molecules or ions that can be encapsulated via their adsorption into framework structures to create a host-guest complex. This is an ever-growing field of study and, as such, the search for more suitable porous materials for environmental applications is fundamental to progress. However, many industrial areas that require the use of adsorbents are fraught with practical challenges such as high temperatures, rapid gas expansion, radioactivity, or repetitive gas cycling, that the host material must withstand. Inorganic phosphates have a proven history of rigid structures, thermal stability, and are suspected to possess good resistance to radiation over geologic time scales. Furthermore, various experimental studies have established their ability to adsorb small molecules, such as water. In light of this, all known crystal structures of phosphate frameworks with meta- (P3O9) or ultra- (P5O14) stoichiometries are combined in a data-mining survey together with all theoretically possible structures of LnaPbOc (where a, b, c are any integer, and Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, or Tm) that are statistically likely to form. Topological patterns within these framework structures are used to assess their suitability for hosting a variety of small guest molecules or ions that are important for environmental applications: CO2, H2O, UO2, PuO2, U, Pu, Sr2+, Cs+, CH4 and H2. A range of viable phosphate-based host-guest complexes are identified from this data-mining and pattern-based structural analysis. Moreover, distinct topological preferences for hosting such guests are found, and metaphosphate stoichiometries are generally preferred over ultraphosphate configurations.},
doi = {10.1021/acssuschemeng.6b00316},
journal = {ACS Sustainable Chemistry & Engineering},
number = 8,
volume = 4,
place = {United States},
year = 2016,
month = 6
}

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  • The identification of inorganic materials, which are able to encapsulate environmentally important small molecules or ions via host-guest interactions, is crucial for the design and development of next-generation energy sources and for storing environmental waste. Especially sought after are molecular sponges with the ability to incorporate CO 2, gas pollutants, or nuclear waste materials such as UO 2 and PuO 2 oxides or U, Pu, Sr 2+ or Cs + ions. Porous framework structures promise very attractive prospects for applications in environmental technologies, if they are able to incorporate CH 4 for biogas energy applications, or to store H 2,more » which is important for fuel cells e.g. in the automotive industry. All of these applications should benefit from the host being resistant to extreme conditions such as heat, nuclear radiation, rapid gas expansion, or wear and tear from heavy gas cycling. As inorganic tungstates are well known for their thermal stability, and their rigid open-framework networks, the potential of Na 2O-Al 2O 3-WO 3 and Na 2O-WO 3 phases for such applications was evaluated. To this end, all known experimentally-determined crystal structures with the stoichiometric formula M aM’ bW cO d (M = any element) are surveyed together with all corresponding theoretically calculated Na aAl bW cO d and Na xW yO z structures that are statistically likely to form. Network descriptors that categorize these host structures are used to reveal topological patterns in the hosts, including the nature of porous cages which are able to accommodate a certain type of guest; this leads to the classification of preferential structure types for a given environmental storage application. Crystal structures of two new tungstates NaAlW 2O 8 (1) and NaAlW 3O 11 (2) and one updated structure determination of Na 2W 2O 7 (3) are also presented from in-house X-ray diffraction studies, and their potential merits for environmental applications are assessed against those of this larger data-sourced survey. Altogether, results show that tungstate structures with three-nodal topologies are most frequently able to accommodate CH 4 or H 2, while CO 2 appears to be captured by a wide range of nodal structure types. The computationally generated host structures appear systematically smaller than the experimentally determined structures. For the structures of 1 and 2, potential applications in nuclear waste storage seem feasible.« less
  • The well-known synthetic versatility of MOFs is rooted in the ability to predict the metal ion coordination geometry and the vast possibilities to use organic chemistry to modify the linker groups. However, the use of “non-innocent” guest molecules as a component of framework design has been largely ignored. Nevertheless, recent reports show that the presence of guest molecules can have dramatic effects, even when these are seemingly innocuous species such as water or polar solvents. Advantages of using guests to impart new properties to MOFs include the relative ease of introducing new functionalities, the ability to modify the properties materialmore » at will by removing the guest or inserting different ones, and avoidance of the difficulties associated with synthesizing new frameworks, which can be challenging even when the basic topology remains constant. In this article we describe the “Guest@MOF” concept and provide examples illustrating its potential as a new MOF design element.« less
  • The physical properties of [CuL{sup 1} {sub 2}(H{sub 2}O)] (1) and [CuL{sup 2} {sub 2}(H{sub 2}O)] (2) and preparation and crystal structures of the inclusion compounds 1.(P)-C{sub 2}H{sub 4}Br{sub 2}, 2.(M)-C{sub 2}H{sub 4}Br{sub 2}, 1.CH{sub 3}CN and 2.CH{sub 3}CN are described. HL{sup 1} and HL{sup 2} (H represents the dissociable phenolic proton) are the N,O-donor chiral reduced Schiff bases N-(2-hydroxy-5-nitrobenzyl)-(R)-{alpha}-methyl-benzylamine and N-(2-hydroxy-5-nitrobenzyl)-(S)-{alpha}-methylbenzylamine, respectively. All the compounds crystallize in the non-centrosymmetric space group C2. In the crystal lattice, the host [CuL {sup n} {sub 2}(H{sub 2}O)] (1 and 2) molecules connected by O-H...O and C-H...O interactions form perfectly polar two-dimensional networks.more » In these chiral and polar host frameworks, enantiospecific inclusion with polar ordering of the right-handed (P) and the left-handed (M) gauche form of 1,2-dibromoethane as well as polar alignment of acetonitrile molecules are observed. The host and guest molecules are linked by C-H...O interactions. The O-atoms of the nitro substituent on the ligands of 1 and 2 act as the acceptors in all these intermolecular O-H...O and C-H...O interactions. The structures reported in this work provide rare examples of enantiospecific trapping of the chiral rotamers of 1,2-dibromoethane as well as perfectly polar alignment of both guest and host molecules. - Graphical abstract: The square-pyramidal Cu(II) complexes [CuL {sup n} {sub 2}(H{sub 2}O)] with the bidentate HL {sup n} (HL{sup 1}=N-(2-hydroxy-5-nitrobenzyl)-(R)-{alpha}-methyl-benzylamine and HL{sup 2}=N-(2-hydroxy-5-nitrobenzyl)-(S)-{alpha}-methylbenzylamine) form 1:1 host-guest compounds with Br(CH{sub 2}){sub 2}Br and CH{sub 3}CN. The X-ray structures of these species reveal the enantiospecific confinement of the chiral rotamers of Br(CH{sub 2}){sub 2}Br and perfectly polar ordering of both host and guest molecules in the crystal lattice. The figure shows the polar alignments of (a) [CuL{sup 1} {sub 2}(H{sub 2}O)].(P)-C{sub 2}H{sub 4}Br{sub 2} and (b) [CuL{sup 2} {sub 2}(H{sub 2}O)].CH{sub 3}CN.« less
  • The host–guest interaction between metal ions (Pt 2+ and Cu 2+) and a zirconium metal–organic framework (UiO-66-NH2) was explored using dynamic nuclear polarization-enhanced 15N{1H} CPMAS NMR spectroscopy supported by X-ray absorption spectroscopy and density functional calculations. The combined experimental results conclude that each Pt 2+ coordinates with two NH2 groups from the MOF and two Cl - from the metal precursor, whereas Cu 2+ do not form chemical bonds with the NH2 groups of the MOF framework. Density functional calculations reveal that Pt 2+ prefers a square-planar structure with the four ligands and resides in the octahedral cage of themore » MOF in either cis or trans configurations.« less
  • The host–guest interaction between metal ions (Pt²⁺ and Cu²⁺) and a zirconium metal–organic framework (UiO-66-NH₂) was explored using dynamic nuclear polarization-enhanced ¹⁵N{¹H} CPMAS NMR spectroscopy supported by X-ray absorption spectroscopy and density functional calculations. The combined experimental results conclude that each Pt²⁺ coordinates with two NH₂ groups from the MOF and two Cl⁻ from the metal precursor, whereas Cu²⁺ do not form chemical bonds with the NH₂ groups of the MOF framework. Density functional calculations reveal that Pt²⁺ prefers a square-planar structure with the four ligands and resides in the octahedral cage of the MOF in either cis or transmore » configurations.« less