Terpenes Show Nanomolar Affinity and Selective Binding with Cucurbit[8]uril

Abstract

Eucalyptol, fenchyl alcohol, and geranylamine were tested for the binding to cucurbit[8]uril. Nanomolar affinities were found, giving rise to a highly selective binding of the terpenes by cucurbit[8]uril when compared to the smaller cucurbit[7]uril. This was rationalized with a better size fit with the larger macrocycle. These notions were supported by the calculation of the packing coefficient and NMR measurements of the free and complexed terpenes. The binding process is mainly enthalpically driven, which is associated with the release of high‐energy water.

Tuning the Sign and Magnitude of Complexation‐Induced pKa Shifts in Cucurbit[7]uril Host‐Guest Complexes by Molecular Engineering

“…Their intriguing binding abilities have been subjected to several theoretical and experimental studies, being now generally accepted that the main driving force accounting for the CBn complexation free energy is the release of high energy water molecules from their hydrophobic cavity upon guest inclusion (e. g. non‐classical hydrophobic effect) [9–11] . This notion is supported by the enthalpy‐driven high binding affinities of CBn towards neutral, complementary‐shaped organic guest molecules [11–16] . The stability of the host‐guest complexes can be further augmented, by factors of up to ca.…”

“…[9][10][11] This notion is supported by the enthalpy-driven high binding affinities of CBn towards neutral, complementary-shaped organic guest molecules. [11][12][13][14][15][16] The stability of the host-guest complexes can be further augmented, by factors of up to ca. À 23 kJ.mol À 1 , for cavity-complementary guests decorated with positively charged substituents that establish attractive electrostatic interactions with the carbonyl portals of the CBn receptor.…”

Screening Power of End-Point Free-Energy Calculations in Cucurbituril Host–Guest Systems

“…Finally, concerning the construction of data set, we select two species from the CB n family with the highest popularity (the 7-unit CB7 and 8-unit CB8) as the target that guests/ligands bind to, in order to achieve high representativity and general interest and extract 91 CB7-guest and 63 CB8-guest pairs, − resulting in a CB n host–guest data set with 154 entries. The chemical structures of all guest molecules are shown in Figure S1.…”

Toward Light-Controlled Supramolecular Peptide Dimerization

“…The stepwise binding constants show a high uncertainty, and for the same reasons as stated earlier by Urbach and co-workers, we report here just the overall 2:1 binding affinity . The binding of NVoc-FGG is clearly enthalpy-driven (Δ H = −41.5 kJ mol –1 , − T Δ S = 7.3 kJ mol –1 ; in neutral water at 25 °C), being indicative of good shape and size complementarity between the receptor cavity and the included ligand moiety. ,,, In the case of FGG, reliable Δ H values for the separate 1:1 and 2:1 binding events could not be obtained due to the observed strong correlation between these two parameters. The stoichiometries of the NVoc-FGG@CB8 and FGG 2 @CB8 complexes were also detected by mass spectrometry (see Figures S10 and S11 in the Supporting Information).…”