Post-synthetic modification within MOFs: a valuable strategy for modulating their ferroelectric performance

It is a great route designing new MOF ferroelectrics to enrich the scope of ferroelectrics or improving the ferroelectric performance to enhance the opportunity of applications through the strategy of post-synthetic modification (PSM).

Effect of carbon-skeleton isomerism on the dielectric properties and proton conduction of organic cocrystal compounds assembled from 1,2,4,5-benzenetetracarboxylic acid and piperazine derivatives

Two isostructural 2D supramolecular cocrystal compounds show different dielectric responses and proton conductivities due to the alteration of the carbon-skeleton of piperazine derivatives.

A three-dimensional metal–organic framework for a guest-free ultra-low dielectric material

A three-dimensional metal–organic framework compound [NH₂(CH₃)₂]₂[Zn₃(bpdc)₄]·3DMF (1) shows two step dielectric relaxation and its guest-free framework (1′) possesses an ultra-low κ value of 1.80 (at 100 kHz, it is the lowest value for MOFs reported to date) over a wide temperature range and high thermal stability.

A MOFs compound [NH₂(CH₃)₂]₂[Zn₃(bpdc)₄]·3DMF (1) shows two step dielectric relaxation and its guest-free framework (1′) possesses an ultra-low κ value of 1.80 (at 100 kHz) over a wide temperature range and high thermal stability.

A multi-functional iodoplumbate-based hybrid crystal: 1-propyl-4-aminopyridinium triiodoplumbate

The temperature-dependent photoluminescence, dielectric and impedance spectra, as well as crystal structures have been investigated for the iodoplumbate-based hybrid crystal, [C₃-Apy][PbI₃] (1) (C₃-Apy⁺ = 1-propyl-4-aminopyridinium).

Mechanochemical Synthesis of 3d Transition-Metal-1,2,4-Triazole Complexes as Precursors for Microwave-Assisted and Thermal Conversion to Coordination Polymers with a High Influence on the Dielectric Properties

The complexes [MCl2 (TzH)4] (M=Mn (1), Fe (2); TzH=1,2,4-1H-triazole) and [ZnCl2 (TzH)2] (3) have been obtained by mechanochemical reactions of the corresponding divalent metal chloride and 1,2,4-1H-triazole. They were successfully used as precursors for the formation of coordination polymers either by a microwave-assisted reaction or by thermal conversion. For manganese, the conversion directly yielded 1∞ [MnCl2 TzH] (4), whereas for the iron-containing precursor, 1∞ [FeCl2 TzH] (6), was formed via the intermediate coordination polymer 1∞ [FeCl(TzH)2]Cl (5). For cobalt, the isotypic polymer 1∞ [CoCl(TzH)2]Cl (7) was obtained, but exclusively by a microwave-induced reaction directly from CoCl2 . The crystal structures were resolved from single crystals and powders. The dielectric properties were determined and revealed large differences in permittivity between the precursor complexes and the rigid chain-like coordination polymers. Whereas the monomeric complexes exhibit very different dielectric behaviour, depending on the transition metal, from "low-k" to "high-k" with the permittivity ranging from 4.3 to >100 for frequencies of up to 1000 Hz, the coordination polymers and complexes with strong intermolecular interactions are all close to "low-k" materials with very low dielectric constants up to 50 °C. Therefore, the conversion procedures can be used to deliberately influence the dielectric properties from complex to polymer and for different 3d transition-metal ions.

Compact film fabrication of porous coordination polymer Co3[Co(CN)6]2 and its reversible vapochromic behavior

The compact films of porous coordination polymer Co₃[Co(CN)₆]₂, fabricated using a layer-by-layer assembly approach, are highly sensitive to organic vapors and the vapochromic process is reproducible and reversible.

The low dielectric constant and relaxation dielectric behavior in hydrogen-bonding metal–organic frameworks

A 3D hydrogen-bonding metal–organic framework shows a low dielectric constant and relaxation dielectric behavior at high temperature.

Dielectric response and anhydrous proton conductivity in a chiral framework containing a non-polar molecular rotor

A chiral 3D framework containing a nonpolar rotor shows two dielectric anomalies and can serve as a proton conductor under high-temperature and anhydrous conditions.