Metal coordination to a deep cavitand promotes binding selectivities in water

• Published in: Chinese chemical letters Vol. 33; no. 11; pp. 4908 - 4911
• Main Authors: Chen, Yong-Qing, Guan, Hua-Wei, Kanagaraj, Kuppusamy, Rebek, Julius, Yu, Yang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2022; Skaggs Institute for Chemical Biology and Department of Chemistry,The Scripps Research Institute,La Jolla,CA 92037,United States; Center for Supramolecular Chemistry and Catalysis and Department of Chemistry,College of Science,Shanghai University,Shanghai 200444,China%Center for Supramolecular Chemistry and Catalysis and Department of Chemistry,College of Science,Shanghai University,Shanghai 200444,China
• Subjects: Host-guest chemistry; Hydrophilic small molecules; Metallo cavitand; Molecular recognition; Water-soluble containers; Molecular recognition; Metallo cavitand; Hydrophilic small molecules; Host-guest chemistry; Water-soluble containers
• ISSN: 1001-8417; 1878-5964
• DOI: 10.1016/j.cclet.2022.03.039

One goal of supramolecular chemistry is the creation of synthetic receptors that have a high affinity for hydrophilic molecules in water. We found that cavitands with upper rims extended by pyridyl groups coax hydrophilic guests into the cavity where they are shielded from the aqueous environment. The ability of Pd(II) to coordinate adjacent pyridyl groups leads to increased selectivity for highly hydrophilic solvent molecules such as acetone, 1,4-dioxane and tetrahydrofuran in water. Analysis of the binding behavior indicated that metal-coordination restricts the container entrance, shrinks the effective cavity volume and increases the energetic barrier to guest exchange. Water-soluble cavitands with pyridyl rims coordinate to Pd(II) and confine hydrophilic solvent molecules such as acetone, 1,4-dioxane and tetrahydrofuran. [Display omitted]