Facile mechanosynthesis of amorphous zeolitic imidazolate frameworks.

Journal of the American Chemical Society 133:37 (2011) 14546-14549

Authors:

Thomas D Bennett, Shuai Cao, Jin Chong Tan, David A Keen, Erica G Bithell, Patrick J Beldon, Tomislav Friscic, Anthony K Cheetham

Abstract:

A fast and efficient mechanosynthesis (ball-milling) method of preparing amorphous zeolitic imidazolate frameworks (ZIFs) from different starting materials is discussed. Using X-ray total scattering, N(2) sorption analysis, and gas pycnometry, these frameworks are indistinguishable from one another and from temperature-amorphized ZIFs. Gas sorption analysis also confirms that they are nonporous once formed, in contrast to activated ZIF-4, which displays interesting gate-opening behavior. Nanoparticles of a prototypical nanoporous substituted ZIF, ZIF-8, were also prepared and shown to undergo amorphization.

Identification of the elusive hydronium ion exchanging roles with a proton in an enzyme at lower pH values.

Angewandte Chemie (International ed. in English) 50:33 (2011) 7520-7523

Authors:

Andrey Y Kovalevsky, BL Hanson, SA Mason, T Yoshida, SZ Fisher, M Mustyakimov, VT Forsyth, MP Blakeley, DA Keen, Paul Langan

Crystal structure determinations of Zr Rich-PbZr1-x Ti x O3

Ferroelectrics 414:1 (2011) 147-154

Authors:

H Yokota, N Zhang, PA Thomas, AM Glazer

Abstract:

TOF experiments were carried out at room temperature and high temperature for Zr rich PbZr1-xTixO3 powders. The best R-factors were obtained with a mixture of R3c and Cm phases. The composition of the Cm phase monotonically increases towards the MPB. At high temperature in the cubic phase, the ADPs for the Pb atom become smaller when Pb displacements along either >110111

Structural investigation of LN/LT1 superlattice thin films by field effect scanning transmission electron microscopy equipped with electron disspersive x-ray spectroscopy

Institute of Electrical and Electronics Engineers (IEEE) (2011) 1-4

Authors:

T Kobata, G Tsukahara, Y Uesu, S Huband, S Gorfman, D Walker, P Thomas, H Yokota, M Glazer, A Bartasyte

Reversible pressure-induced amorphization of a zeolitic imidazolate framework (ZIF-4).

Chemical communications (Cambridge, England) 47:28 (2011) 7983-7985

Authors:

Thomas D Bennett, Petra Simoncic, Stephen A Moggach, Fabia Gozzo, Piero Macchi, David A Keen, Jin-Chong Tan, Anthony K Cheetham

Abstract:

We report the reversible pressure-induced amorphization of a zeolitic imidazolate framework (ZIF-4, [Zn(Im)(2)]). This occurs irrespective of pore occupancy and takes place via a novel high pressure phase (ZIF-4-I) when solvent molecules are present in the pores. A significant reduction in bulk modulus upon framework evacuation is also observed for both ZIF-4 and ZIF-4-I.