Crystals springing into action: metal–organic framework CUK-1 as a pressure-driven molecular spring

Abstract

Mercury porosimetry and in situ high pressure single crystal X-ray diffraction revealed the wine-rack CUK-1 MOF as a unique crystalline material capable of a fully reversible mechanical pressure-triggered structural contraction....

Structural Chemistry of Metal–Organic Frameworks under Hydrostatic Pressures

“…First, MOFs as a material platform offer control over chemical bond strength, porosity, and topologya well-known but still unique selling point, giving rise to unusual chemistries and physics at high pressures, 191 which include phenomena such as pressure-induced phase transitions, negative linear or area compressibility, and unexpected PTM-dependent behavior. While such properties are not yet coupled to dedicated applications, they might form the basis for next-generation technologies such as mechanical energy storage 162 and barocalorics, 192 where high-pressure diffraction experiments are key. Research in this direction, i.e.…”

“…Reversibility and the nature of hysteretic behavior is important for the use of MOFs in pressure-induced energy storage processes. In a recent study, P. G. Yot and co-workers investigated CUK-1 (M 3 (pdc) 2 (μ 3 -OH) 2 ]·9H 2 O with M 2+ = Co 2+ , Mg 2+ ), reporting a fully reversible compression without hysteretic behavior; a desirable property for energy storage as the energy loss during storage is minimized . Looking at the (irreversible) amorphization of a MOF via pressure, it fundamentally represents a crystalline-to-amorphous phase transition.…”

“…In a recent study, P. G. Yot and co-workers investigated CUK-1 (M 3 (pdc) 2 (μ 3 -OH) 2 ]•9H 2 O with M 2+ = Co 2+ , Mg 2+ ), reporting a fully reversible compression without hysteretic behavior; a desirable property for energy storage as the energy loss during storage is minimized. 162 Looking at the (irreversible) amorphization of a MOF via pressure, it fundamentally represents a crystalline-toamorphous phase transition. In addition to the previously mentioned examples, the family of zeolitic imidazolate frameworks represents a good example in this context, showing different behaviors within one subclass of MOFs.…”

Structural phase transitions in flexible DUT-8(Ni) under high hydrostatic pressure

“…This could open a new direction in the creation of metamaterials capable of instantaneous energy storage. 24 The pressure effect on the order–disorder ferroelectric transition was demonstrated in [(CH 3 ) 2 NH 2 ]Co(HCOO) 3 , providing a comprehensive understanding of the relationship between structural distortion and ferroelectricity. 25…”

Designing Geometric Degrees of Freedom in ReO3-Type Coordination Polymers

“…In coordination polymers, the simple use of molecular scaffolds introduces new unconventional structural degrees of freedom compared to solid-state inorganics. Examples are orientational degrees of freedom related to order-disorder phase transitions in the barocaloric [(C 3 H 7 ) 4 N]Mn(C 2 N 3 ) 3 and photovoltaic absorber [CH 3 NH 3 ]PbI 3 2, 13 , large translational network deformations in the flexible metal-organic frameworks (MOFs) CUK-1 and DMOF-1 derivatives 14,15 with potential in mechanical energy storage processes, and rotational molecular motions in amphidynamic MOFs 16 as a basis for coordination polymer-based molecular machines. The concept conceptualizes current and past research progress related to stimuli-responsive properties in coordination polymers, and in looking forward, engineering the interplay of several structural degrees of freedom shows large promise in the design of materials with targeted and potentially new stimuli-responsive properties.…”