High pressure effects on hydrate Cu-BTC investigated by vibrational spectroscopy and synchrotron X-ray diffraction

Abstract

The high pressure behaviors of hydrate Cu-BTC metal-organic framework (MOF) in terms of phase stability, compressibility and reversibility were investigated in situ by synchrotron X-ray powder diffraction as well as vibrational spectroscopy. Two phase transitions, caused by the interaction of water and the sample framework, were revealed by the vibrational spectroscopies. Compressibility of the hydrate Cu-BTC also displays soft and hard regimes, which is the same scenario as non-hydrate Cu-BTC with a pressure transmitting medium. It is further confirmed that the residual water molecules in hydrate Cu-BTC can serve as a pressure transmitting medium with small molecule size under high pressure. Our results not only prove the high stability of Cu-BTC but also provide spectroscopic evidence for the interactions taking place between the guest molecules and the sample framework. Such findings could provide further guidelines for improving Cu-BTC's absorption and storage abilities.

A Cu(ii)-MOF based on a propargyl carbamate-functionalized isophthalate ligand

“…32,33 In the lowfrequencies region (600-200 cm À1 range), [Cu(1,3-YBDC)]$ xH 2 O exhibits, in agreement with previous studies, two peaks at 495 and 276 cm À1 , respectively assigned to the vibrational stretching modes of equatorial and axial Cu-O bonds. 34,35 The elemental analysis of the synthesized sample is in good agreement with the theoretical chemical composition, showing a Cu/N molar ratio of ca. 1 (see Experimental part).…”

Poly(ionic liquid)-based engineered mixed matrix membranes for CO2/H2 separation

“…The region below 1150 cm -1 is where most vibrational modes of the BTC ligand are detected. The peak at 1110 cm -1 and the peaks at 758 cm -1 and 729 cm -1 correspond to the inplane and out-of-plane C-H bending modes, respectively, all associated with the aromatic ring of the BTC ligand [37].…”

NiFe2O4@SiO2@Cu3(BTC)2 nanocomposite as a magnetic metal–organic framework

“…These characteristic peaks are proven for the identification of Cu 3 (BCT) 2 . [ 36 ] As can be seen, the existence of similar characteristic peaks in the composite compound approved the formation of the MOF structure in the aimed sample.…”