Host-Guest Chemistry of Carboranes: Synthesis of Carboxylate Derivatives and Their Binding to Cyclodextrins

Jan Nekvinda; Bohumír Grüner; Detlef Gabel; Werner M Nau; Khaleel I Assaf

doi:10.1002/chem.201802134

Host-Guest Chemistry of Carboranes: Synthesis of Carboxylate Derivatives and Their Binding to Cyclodextrins

Chemistry. 2018 Sep 3;24(49):12970-12975. doi: 10.1002/chem.201802134. Epub 2018 Jul 26.

Authors

Jan Nekvinda^{1

2}, Bohumír Grüner¹, Detlef Gabel³, Werner M Nau³, Khaleel I Assaf³

Affiliations

¹ Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, v.v.i., Hlavní 1001, 250 68, Řež, Czech Republic.
² Department of Organic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 42, Prague 2, Czech Republic.
³ Jacobs University Bremen, Department of Life Sciences and Chemistry, Campus Ring 1, 28759, Bremen, Germany.

PMID: 29893507
DOI: 10.1002/chem.201802134

Abstract

Polyhedral carboxymethyl carborane (C₂ B₁₀ H₁₂ ) derivatives, including mono- and disubstituted o-, m-, and p-isomers, have been synthesized. Supramolecular host-guest complexation of these derivatives with cyclodextrins (CDs; namely, α-, β-, and γ-CD) has been investigated in water. The globular structure of the carborane binding moiety and its hydrophobic character qualify it as an ideal recognition site to form stable inclusion complexes with macrocyclic host molecules in aqueous solution. The measured binding affinities for the carborane derivatives were in the millimolar range (K_a =10³ -10⁴ m^-1 ) with differently sized CDs, and preferential binding to β-CD.

Keywords: boron; carboranes; cluster compounds; host-guest systems; hydrophobic effect.