High-pressure sapphire capillary cell for synchrotron single-crystal X-ray diffraction measurements to 1500 bar

Abstract

A new sapphire capillary pressure cell for single-crystal X-ray diffraction measurements at moderate pressures (200−1500 bar; 1 bar = 100 kPa) has been developed and optimized for use on beamline I19 at Diamond Light Source. The three-component cell permits optical centring of the crystal and in situ pressure modification to a precision of 1 bar. Compression of hexamethylenetetramine and its deuterated analogue to 1000 bar was performed, showcasing the accuracy and precision of the measurements, and highlighting evidence of a geometric isotope effect.

Pressure and guest-mediated pore shape modification in a small pore MOF to 1200 bar

“…25 By contrast, compression of the framework in a PTM of isopentane from ambient pressure to 1200 bar resulted in direct compression of the unit cell by 11(1) Å 3 (-0.18 %). The precision obtained in these measurements reflects that of the data collected previously on hexamethylenetetramine (or HMTH), 22 making this cell ideal for studying very flexible systems under compression of a variety of fluids. The compressibility of Sc 2 BDC 3 in isopentane corresponds to a relatively high bulk modulus, K 0 , of 48(2) GPa, calculated using a third-order Birch-Murnaghan equation of state in the EoSFit7 program 26 (Supplementary Information S3) and a comparison to the bulk moduli of other MOFs is shown in Supplementary Table S3.…”

“…25 By contrast, compression of the framework in a PTM of isopentane from ambient pressure to 1200 bar resulted in direct compression of the unit cell by 11(1) Å 3 (À0.18%). The precision obtained in these measurements reflects that of the data collected previously on hexamethylenetetramine (or HMTH), 22 making this cell ideal for studying very flexible systems under compression of a variety of fluids.…”

“…With this in mind, we recently developed a sapphire capillary cell (SCC, Figure 2) which addresses this issue, and is designed for in situ single crystal X-ray diffraction using liquid PTM from ambient pressure to 1500 bar. 22 Here, the SCC is used to extend previous work on the pore-shape modification of Sc 2 BDC 3 upon adsorption of n-pentane or isopentane between 50-1200 bar, with the aim of clarifying the mechanism for the rotation of the Group 2 BDC linker at lower pressures. This is the first atomistic structural analysis of any metal-organic framework under these types of pressure conditions, using a cell capable of studying in detail, the uptake of a variety of guest species into the pores.…”

Design and use of a sapphire single-crystal gas-pressure cell forin situneutron powder diffraction

“…Single-crystal tubes as sample holders are also known in neutron spectroscopy (Rondinone et al, 2003) and are widely used in synchrotron powder diffraction (Jensen et al, 2010). A gas-pressure cell similar to the one described in this contribution was recently reported for single-crystal X-ray diffraction (McMonagle et al, 2020). Gas-pressure cells for small-angle neutron scattering often contain sapphire windows (Xu, 2020).…”

Structural Chemistry of Metal–Organic Frameworks under Hydrostatic Pressures

“…The aforementioned amorphization of MOF-5 and phase transitions of ZIF-4­(Zn,Co) , and MIL-47 are good examples where a high-pressure resolution below p = 0.1 GPa is desirable. Therefore, custom-made high-pressure diffraction setups that allow tracking of changes of lattice parameters in small and well-defined pressure steps with p start = ambient are gaining importance; see Table for a selection of existing custom-made and DAC setups. − The majority of such setups use a hydraulic fluid (or gas) to generate pressure in the sample chamber which contains the PTM and the sample. By increasing the pressure of the hydraulic fluid through pumping, very small and defined pressure steps can be achieved.…”