Pressure inverse solubility and polymorphism of an edible γ-cyclodextrin-based metal–organic framework

Abstract

A very exceptional effect of pressure-induced dissolution has been revealed for an edible metal-organic framework, g-CD-MOF-1, formed using g-cyclodextrin and KOH base. In addition, a new polymorph of g-CD-MOF-1 has been obtained. The trigonal structure is a symmetry sub-group modification of the cubic form. The pressure-induced dissolution of g-CD-MOF-1 and its polymorphism are shown to be closely related and regulated by adsorption in the pores, as well as the guest framework interactions.

Efficient adsorption separation of xylene isomers using a facilely fabricated cyclodextrin‐based metal–organic framework

“…37,38 The 'breath effects' may not only be due to the inherent flexibility and porosity of the -CD linker, but also due to its weak coordination bonds with K + cations. Pressure and temperature were observed to influence the adsorption performance of CD-MOF materials because of their sensitivity to external conditions.…”

“…Pressure and temperature were observed to influence the adsorption performance of CD-MOF materials because of their sensitivity to external conditions. 37,38 The 'breath effects' may not only be due to the inherent flexibility and porosity of the -CD linker, but also due to its weak coordination bonds with K + cations. 38 At 298 K, the amount of mX and pX adsorbed reached their plateau at a pressure of 8 mbar.…”

“…37,38 The 'breath effects' may not only be due to the inherent flexibility and porosity of the -CD linker, but also due to its weak coordination bonds with K + cations. 38 At 298 K, the amount of mX and pX adsorbed reached their plateau at a pressure of 8 mbar. However, at 318 K, the amount adsorbed continued to increase, until the adsorption capacity of pX exceeded that of mX above 17 mbar pressure.…”

Stability and Phase Transitions of Nontoxic γ-Cyclodextrin-K+ Metal-Organic Framework in Various Solvents

“…This MOF (named γ-CD-MOF-1) consists of γ-CD and potassium cations and can be obtained by crystallization from water by the slow vapor diffusion of MeOH. It is known to exist in two crystalline phases, alpha (α) [11] and beta (β) [12]. In addition, α-phase of γ-CD-MOF-1 crystallizes in cubic symmetry with the I432 space group [11], whereas β-phase crystallizes in trigonal symmetry with R32 the space group [12].…”

“…It is known to exist in two crystalline phases, alpha (α) [11] and beta (β) [12]. In addition, α-phase of γ-CD-MOF-1 crystallizes in cubic symmetry with the I432 space group [11], whereas β-phase crystallizes in trigonal symmetry with R32 the space group [12]. Crystal structures of both phases are represented in Figure 1.…”