Reference diffraction patterns, microstructure, and pore-size distribution for the copper (II) benzene-1,3,5-tricarboxylate metal organic framework (Cu-BTC) compounds

摘要

Cu-paddle-wheel-based Cu-3(BTC)(2) (nicknamed Cu-BTC, where BTC equivalent to benzene 1,3,5-tricarboxylate) is a metal organic framework (MOF) compound that adopts a zeolite-like topology. We have determined the pore-size distribution using the Gelb and Gubbins technique, the microstructure using small-angle neutron scattering and (ultra) small-angle X-ray scattering (USAXSSAXS) techniques, and X-ray powder diffraction reference patterns for both dehydrated d-Cu-BTC [Cu-3(C9H3O6)(2)] and hydrated h-Cu-BTC [Cu-3(C9H3O6)(2)(H2O)(6.96)] using the Rietveld refinement technique. Both samples were confirmed to be cubic Fm (3) over bar m (no. 225), with lattice parameters of a = 26.279 19(3) angstrom, V = 18 148.31(6) angstrom(3) for d-Cu-BTC, and a = 26.3103(11) angstrom, and V= 18 213(2) angstrom(3) for h-Cu-BTC. The structure of d-Cu-BTC contains three main pores of which the diameters are approximately, in decreasing order, 12.6, 10.6, and 5.0 angstrom. The free volume for d-Cu-BTC is approximately (71.85 +/- 0.05)% of the total volume and is reduced to approximately (61.33 +/- 0.03)% for the h-Cu-BTC structure. The d-Cu-BTC phase undergoes microstructural changes when exposed to moisture in air. The reference X-ray powder patterns for these two materials have been determined for inclusion in the Powder Diffraction File. (C) 2014 International Centre for Diffraction Data.