Guest-selective shape-memory effect in a switchable metal-organic framework DUT-8(Zn).

Crystal size engineering allows tailoring of flexible metal-organic frameworks (MOFs) to achieve new properties. The gating type flexibility of the DUT-8(Zn) ([Zn(2,6-ndc)(dabco)], 2,6-ndc = 2,6-naphthalene dicarboxylate, dabco = 1,4-diazabicyclo-[2.2.

Particle size-dependent flexibility in DUT-8(Cu) pillared layer metal-organic framework.

The nature of metal in the isomorphous flexible metal-organic frameworks is often reported to influence flexibility and responsivity. A prominent example of such behaviour is the DUT-8() family ([(2,6-ndc)(dabco)], 2,6-ndc = 2,6-naphthalene dicarboxylate, dabco = 1,4-diazabicyclo-[2.2.

The Dilemma of Reproducibility of Gating Isotherms for Flexible MOFs.

Porous materials receive a high level of scientific and technological interest due to their applications in various fields such as adsorption, separation and storage, catalysis, ion exchange, nanotechnology, etc. Gas adsorption is a well-established tool for the characterization of the texture of porous solids. Physisorption isotherms are generally expected to be well reproducible for rigid adsorbents, but this is not always the case for nonrigid (flexible) materials.

Linker Expansion and Its Impact on Switchability in Pillared-Layer MOFs.

Linker elongation is an important method to systematically adjust porosity and pore size in isoreticular MOFs. In flexible structures, this approach opens the possibility for the systematic analysis of the building blocks and their contribution to the overall flexible behavior enabling tuning of the framework responsivity toward molecular stimuli. In this work, we report two new compounds isoreticular to the highly flexible pillared layer structure DUT-8(Ni) ([Ni(2,6-ndc)(dabco)], 2,6-ndc = 2,6-naphthalenedicarboxylate, dabco = 1,4-diazabicylo[2.

Single particle Raman spectroscopy analysis of the metal-organic framework DUT-8(Ni) switching transition under hydrostatic pressure.

Experimental in situ observations of phase coexistence in switchable metal-organic frameworks are reported to provide a fundamental understanding of dynamic adsorbents that can change their pore structure in response to external stimuli. A prototypical flexible pillared layer framework DUT-8(Ni) (DUT = Dresden University of Technology) was studied under hydrostatic pressure by in situ Raman spectroscopy on single crystals. The closing transition of the open pore phase (op) containing DMF in the pores in silicon oil as a pressure transmitting fluid, as well as the closed pore phase (cp) to op transition under pressure in methanol, were studied.

Raman spectroscopy studies of the terahertz vibrational modes of a DUT-8 (Ni) metal-organic framework.

Low-frequency lattice vibrational modes have been discussed to play a crucial role in the phase transformation process of flexible metal-organic frameworks (MOFs). Therefore, Raman spectroscopy was applied to study the lattice dynamics of a pillared layer DUT-8(Ni) framework (DUT - Dresden University of Technology), existing in rigid and flexible forms. Both the open and the close pore phases could be unambiguously identified by breathing mode bands at 23 cm and 60 cm in the corresponding Raman spectra, showing the efficiency of the technique for monitoring the flexibility of MOF materials as well as the differences in the lattice vibrations of the two phases.