Click nanosponge - A novel amine-rich β-cyclodextrin-based crosslinked polymer for heterogeneous catalysis

Tiago F Machado; Gianluca Utzeri; Artur J M Valente; M Elisa Silva Serra; Dina Murtinho

doi:10.1016/j.carbpol.2023.121612

Click nanosponge - A novel amine-rich β-cyclodextrin-based crosslinked polymer for heterogeneous catalysis

Carbohydr Polym. 2024 Feb 15:326:121612. doi: 10.1016/j.carbpol.2023.121612. Epub 2023 Nov 20.

Authors

Tiago F Machado¹, Gianluca Utzeri¹, Artur J M Valente¹, M Elisa Silva Serra¹, Dina Murtinho²

Affiliations

¹ University of Coimbra, CQC-IMS, Department of Chemistry, 3004-535 Coimbra, Portugal.
² University of Coimbra, CQC-IMS, Department of Chemistry, 3004-535 Coimbra, Portugal. Electronic address: dmurtinho@ci.uc.pt.

PMID: 38142073
DOI: 10.1016/j.carbpol.2023.121612

Abstract

Cyclodextrin-based nanosponges are promising materials for heterogeneous catalysis due to their inherent synthetic versatility, tunable porosity and nontoxicity. In this work, a primary amine-rich β-cyclodextrin nanosponge was synthesized via click imine condensation reaction between 1,6-hexamethylamine-functionalized β-cyclodextrin (CDAM) and glutaraldehyde (GLT) to afford CDGLAM, in mild conditions. The crosslinked polymer exhibited a BET surface area of 36.39 m² g^-1, an average pore diameter of 3.09 nm (as assessed by the BJH method), and thermal stability up to 253 °C. CDGLAM was tested as heterogeneous catalyst for the metal-free Henry and Knoevenagel reactions, between aromatic aldehydes and nitromethane or ethyl cyanoacetate, respectively, affording the products in moderate to very high yields. These results show the ease of preparation of β-CD-based nanosponges from a green chemistry perspective, as well as their potential for future use in catalytic systems.

Keywords: Click chemistry; Cyclodextrin; Henry reaction; Heterogeneous metal-free catalysis; Knoevenagel reaction; Nanosponges.