Browsing by Author "Batten, SR"

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    Anisotropic thermal and guest-induced responses of an ultramicroporous framework with rigid linkers
    (John Wiley & Sons, Inc, 2018-02-16) Auckett, JE; Duyker, SG; Izgorodina, EI; Hawes, CS; Turner, DR; Batten, SR; Peterson, VK
    The interdependent effects of temperature and guest uptake on the structure of the ultramicroporous metal–organic framework [Cu3(cdm)4] (cdm=C(CN)2(CONH2)−) were explored in detail by using in situ neutron scattering and density functional theory calculations. The tetragonal lattice displays an anisotropic thermal response related to a hinged “lattice-fence” mechanism, unusual for this topology, which is facilitated by pivoting of the rigid cdm anion about the Cu nodes. Calculated pore-size metrics clearly illustrate the potential for temperature-mediated adsorption in ultramicroporous frameworks due to thermal fluctuations of the pore diameter near the value of the target guest kinetic diameter, though in [Cu3(cdm)4] this is counteracted by a competing contraction of the pore with increasing temperature as a result of the anisotropic lattice response. © 2018 Wiley-VCH Verlag GmbH & Co.
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    Insights into selective gas sorbent functionality gained by using time-resolved neutron diffraction
    (John Wiley & Sons, Inc, 2018-05-05) Auckett, JE; Duyker, SG; Turner, DR; Batten, SR; Peterson, VK
    An understanding of the atomic-scale interactions between gas sorbent materials and their molecular guests is essential for the identification of the origins of desirable function and the rational optimization of performance. However, characterizations performed on equilibrated sorbent–guest systems may not accurately represent their behavior under dynamic operating conditions. The emergence of fast (minute-scale) neutron powder diffraction coupled with direct, real-time quantification of gas uptake opens up new possibilities for obtaining knowledge about concentration-dependent effects of guest loading upon function-critical features of sorbent materials, including atomic structure, diffusion pathways, and thermal expansion of the sorbent framework. This article presents a detailed investigation of the ultramicroporous metal–organic framework [Cu3(cdm)4] as a case study to demonstrate the variety of insights into sorbent performance that can be obtained from real-time characterizations using neutron diffraction. © 2018 Wiley-VCH Verlag GmbH & Co
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    A neutron diffraction study of hydrogen bonding in isostructural potassium and ammonium lanthanoidates
    (Royal Society of Chemistry, 2014-10-08) Emerson, AJ; Edwards, AJ; Batten, SR; Turner, DR
    Two isostructural series of compounds NH4[Ln(cdm)4(H2O)4]·18c6·3H2O (1Ln) and [K(18c6)(H2O)2][Ln(cdm)4(H2O)4]·H2O (2Ln) have been synthesised and structurally characterised (Ln = Gd, Dy, Er, cdm = C(CN)2(CONH2)−). These two classes of compounds are shown to be essentially isostructural to each other despite the change in counter-cation (ammonium vs. potassium) and the ensuing changes in coordination and hydrogen-bonding of water molecules in the structure. Structural data for 1Dy and 2Dy have been obtained using single crystal Laue neutron diffraction, allowing the precise location of all hydrogen atoms to be determined using fully anisotropic models. Both 1 and 2 contain the anionic complex [Ln(cdm)4(H2O)4]− in which the 8-coordinate lanthanoid is coordinated by a ring of four O-bound cdm ligands supported by inter-ligand N–H⋯O hydrogen bonds. The structures pack with complicated hydrogen-bonding networks in which both coordinated and non-coordinated water molecules are hydrogen-bond donors and all of the nitrile groups of the cdm ligands are hydrogen-bond acceptors. The change in cation between ammonium and potassium affects two water molecule sites which are both coordinated in 2Ln but not in 1Ln; in 1Ln one of these water molecules forms a hydrogen bond with NH4+ whilst the other has neither a coordination interaction nor a hydrogen bond to its oxygen atom. © The Royal Society of Chemistry.
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    Ultramicroporous MOF with high concentration of vacant Cu 11 sites
    (American Chemical Society, 2015-07) McCormick, LJ; Duyker, SG; Thornton, AW; Hawes, CS; Hill, MR; Peterson, VK; Batten, SR; Turner, DR
    An ultramicroporous metal–organic framework (MOF) is reported that contains 0.35 nm nanotube-like channels with an unprecedented concentration of vacant CuII coordination sites. The nonintersecting, narrow channels in [Cu3(cdm)4] (cdm = C(CN)2(CONH2)−) align in two perpendicular directions, structurally resembling copper-doped carbon nanotubes with CuII embedded in the walls of the channels. The combination of ultramicroporosity with the exposed CuII coordination sites gives size-based selectivity of CO2 over CH4, based on pore-size distribution and modeling. Neutron powder diffraction and molecular dynamics simulations show the close packing of single rows of guests within the tubular nanostructure and interaction of CO2 with the exposed metal sites. © 2014, American Chemical Society.