20 research outputs found
Semi-analytical mean-field model for predicting breathing in metalâorganic frameworks
A breathing zirconium metal-organic framework with reversible loss of crystallinity by correlated nanodomain formation
The isoreticular analogue of the metal-organic framework UiO-66(Zr), synthesized with the flexible trans-1,4-cyclohexanedicarboxylic acid as linker, shows a peculiar breathing behavior by reversibly losing long-range crystalline order upon evacuation. The underlying flexibility is attributed to a concerted conformational contraction of up to two thirds of the linkers, which breaks the local lattice symmetry. X-ray scattering data are described well by a nanodomain model in which differently oriented tetragonal-type distortions propagate over about 7-10 unit cells
A Comparison of Barostats for the Mechanical Characterization of MetalOrganic Frameworks
Thermodynamic Modeling of the Selective Adsorption of Carbon Dioxide over Methane in the Mechanically Constrained Breathing MILâ53(Cr)
Exploring the Flexibility of MIL-47(V)-Type Materials Using Force Field Molecular Dynamics Simulations
Ab Initio Parametrized Force Field for the Flexible MetalâOrganic Framework MIL-53(Al)
A force field is proposed for the flexible metalâorganic
framework MIL-53Â(Al), which is calibrated using density functional
theory calculations on nonperiodic clusters. The force field has three
main contributions: an electrostatic term based on atomic charges
derived with a modified Hirshfeld-I method, a van der Waals (vdW)
term with parameters taken from the MM3 model, and a valence force
field whose parameters were estimated with a new methodology that
uses the gradients and Hessian matrix elements retrieved from nonperiodic
cluster calculations. The new force field predicts geometries and
cell parameters that compare well with the experimental values both
for the large and narrow pore phases. The energy profile along the
breathing mode of the empty material reveals the existence of two
minima, which confirms the intrinsic bistable behavior of the MIL-53.
Even without the stimulus of external guest molecules, the material
may transform from the large pore (lp) to the narrow pore (np) phase
[Liu et al. <i>J. Am. Chem. Soc.</i> <b>2008</b>, <i>120</i>, 11813]. The relative stability of the two phases critically
depends on the vdW parameters, and the MM3 dispersion interaction
has the tendency to overstabilize the np phase
Unraveling the thermodynamic conditions for negative gas adsorption in soft porous crystals
Mechanical energy storage performance of an aluminum fumarate metalâorganic framework
International audienc
A Breathing Zirconium Metal-Organic Framework with Reversible Loss of Crystallinity by Correlated Nanodomain Formation
The isoreticular analogue of the metalâorganic framework UiO-66(Zr), synthesized with the flexible trans-1,4-cyclohexanedicarboxylic acid as linker, shows a peculiar breathing behavior by reversibly losing long-range crystalline order upon evacuation. The underlying flexibility is attributed to a concerted conformational contraction of up to two thirds of the linkers, which breaks the local lattice symmetry. X-ray scattering data are described well by a nanodomain model in which differently oriented tetragonal-type distortions propagate over about 7â10 unit cells.status: publishe