Abstract
Cyclodextrin (CD) has been used to prepare biocompatible and nontoxic metal-organic frameworks (MOFs) suitable for biomedical applications as drug carriers. In this study, γ-CD/K-based MOF (γ-CD-MOF-1-α) was synthesized and its stability in various solvents was explored by single-crystal X-ray diffractometry (SCXRD) and powder X-ray diffractometry (PXRD). As a result of solvent-induced phase transformations, two novel crystalline phases of γ-CD-MOF-1 were discovered. The newly formed ε- and δ-phases crystallize in orthorhombic and tetragonal symmetry, respectively. In ε-phase, toluene was determined as a guest molecule by SCXRD. Interactions between γ-cyclodextrin and solvent molecules in ε-phase were evaluated using Hirshfeld surface analysis. The thermal stability of the new crystal forms of γ-CD-MOF-1 was analyzed by differential scanning calorimetry and thermogravimetric analysis.
Highlights
Over the last two decades, metal-organic frameworks (MOFs) have attracted increased attention due to their diverse properties and tunable structure [1,2]
Designation of the crystalline forms used in this paper: γ-CD-based MOF (CD-MOF)-1-α [11] – α-phase; γ-CD-MOF-1-β [12] – β-phase; γ-CD-MOF-1-δ – δ-phase; γ-CD-MOF-1-ε – ε-phase; γ-CD-MOF-1-ε·tol – ε·tol-phase
The solubility of γ-CD-MOF-1 in selected solvents was assessed by 1 H NMR spectra (Supplementary Materials Figures S10–S14) [14]
Summary
Over the last two decades, metal-organic frameworks (MOFs) have attracted increased attention due to their diverse properties and tunable structure [1,2]. Porous biocompatible MOFs inherit many useful features of the class of crystalline coordination polymers simultaneously providing a key advantage, such as low toxicity, which makes them ideal candidates for biomedical applications [3,4]. Several potential drug carrier candidates are already known [2,3,7,8,9,10], with one of the promising classes of such MOFs that meet such criteria being based on a combination of cyclodextrin (CD) molecules and an alkali metal. In 2010, Stoddart et al reported the first CD-based MOF (CD-MOF) [11] 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. Α-phase of γ-CD-MOF-1 crystallizes in cubic symmetry with the
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
