A Chemically Triggered and Thermally Switched Dielectric Constant Transition in a Metal Cyanide Based Crystal

Abstract

A dielectric constant transition is chemically triggered and thermally switched in (HPy)2[Na(H2O)Co(CN)6] (2, HPy=pyridinium cation) by single-crystal-to-single-crystal transformation and structural phase transition, respectively. Upon dehydration, (HPy)2[Na(H2O)2Co(CN)6] (1) transforms to its semi-hydrated form 2, accompanying a transition from a low-dielectric state to a high-dielectric state, and vice versa. This dielectric switch is also realized by a structural phase transition in 2 that occurs between room- and low-temperature phases, and which corresponds to high- and low-dielectric states, respectively. The switching property is due to the variation in the environment surrounding the HPy cation, that is, the hydrogen-bonding interactions and the crystal packing, which exert predominant influences on the dynamics of the cations that transit between the static and motional states.

A Niccolite Structural Multiferroic Metal–Organic Framework Possessing Four Different Types of Bistability in Response to Dielectric and Magnetic Modulation

“…Also, all these plots show little frequency dependence in the measured frequency range of 5K−1M Hz, indicating that the polar motions are much faster than 1 MHz (Figure S5, Supporting Information). Evidently, the dielectric data measured from the single crystal sample of 1 are steeper than that from the powder samples (Figure S5b, Supporting Information) as well as that reported by Maczka et al This phenomenon should be ascribed to the freezing of the DEA cations around the c ‐direction at HTP, which could give rise to an anisotropic dielectric behavior …”

“…For example, Jain et al discovered switchable dielectric constant as a function of temperature in metal formates with perovskite structure . Further studies indicate the dipolar reorientation makes a major contribution to the transition between different dielectric states . This conclusion then suggests the metal‐organic frameworks (MOFs) with mobile guest molecules around the rigid cavities to be a promising candidate for switchable dielectric materials, in which the guests can be viewed as electric dipole moments.…”

Rapid and reversible photoinduced switching of a rotaxane crystal

“…A recent application of crystalline phase transition involves positive or negative thermal expansion based on an anisotropic change of the crystal shape caused by a change in temperature678. Most previous studies have been concerned with full phase transition, where the structure, electronic state and/or conformation of all of the molecules within the crystals vary under crystallographic control145891011. Reversible processes for the repeated performance of crystals require a combination of a double stimulus for the forward and backward phase transition, that is, photoirradiation, temperature change, irradiation at different wavelengths and the backward process is generally 1–2 orders of magnitude slower than the forward process1213141516.…”

Honeycomb‐Patterned Polyimide Film as a Versatile Coating for High‐Performance Dielectric Material

“…Controlling the dielectric properties of materials for use in electronics has attracted considerable attention from both academic and industrial perspectives. [1][2][3][4][5] Low-dielectric-constant materials are of particulari nterest because of their wide use in integrated circuits to reduce electronic signal interference, power dissipation, propagation delay,a nd so on. [6][7][8][9][10] Polyimide (PI) has been generally regarded as one of the candidates with the most potential in this regardo wing to its good chemical and thermals tability alongw ith its noteworthy dielectric and mechanical properties.…”