Never-Ending Story: New Cyclodextrin-Based Metal–Organic Framework Crystal Structures Obtained Using Different Crystallization Methods

Abstract

Six novel cyclodextrin (CD)-based metal–organic frameworks (MOFs) were synthesized using distinct crystallization methodologies. A modified vapor diffusion method is introduced for the first time, termed fast crystallization, which enables the rapid solid-state formation of MOF compounds. This innovative method yielded four of the newly synthesized MOFs. The crystal structures of five obtained frameworks were structurally characterized through single-crystal X-ray diffraction, while one, compound 5 (γ-CD-K-5), was additionally characterized as a bulk powder. Structural analysis revealed that two of the newly obtained MOFs, namely, compound 2 (α-CD-K-2) and compound 3 (α-CD-Rb-3), exhibited isostructural characteristics, forming a three-dimensional (3D) framework. Compound 1 (α-CD-K-1) shared the same space group as EVEGET (α-CD-K) and displayed the same framework type. Furthermore, the crystal packing of compound 4 (β-CD-K-4) closely resembled that of compound 1 and EVEGET, with the only distinction lying in the type of CD employed. Notably, compound 6 (γ-CD-K-6) incorporated an iodine ion with an occupancy of 0.2. To discern the intermolecular interactions within the obtained MOFs, the Hirshfeld surface was calculated using Crystal Explorer software.

Cyclodextrin Metal–Organic Frameworks as a Drug Delivery System for Selected Active Pharmaceutical Ingredients

“…In this study, we aim to overcome these drawbacks by creating new API-encapsulated products within newly obtained γCD-K-5 and γCD-K-6 MOFs. We will characterize the loading capabilities of selected APIs with γCD-K MOFs using various encapsulation protocols and study the API release processes for the obtained host–guest complexes. Additionally, we characterize the structures of the obtained complexes with various physical methods and in vitro and in vivo tests in cells.…”