An adamantane-based disubstituted binding motif with picomolar dissociation constants for cucurbit[n]urils in water and related quaternary assemblies

A non-axial centerpiece based on 1,3-disubstituted adamantane was designed, and three new guests were prepared. In the structure of the heterotritopic guests, the central adamantane site was combined with two terminal butyl or 1-adamantyl sites. The new central binding motif displayed an extraordinarily high affinity towards CB8`(K-a = (5.3 +/- 0.3) x 10(12) M-1 in water) to allow formation of quaternary assemblies with geometries which are dependent on the nature of macrocycles. Based on the individual binding strengths, the replacement of CB7 by CB8 led to inverse arrangements of the quaternary assemblies; i.e., b-CD is capped at the central site by two CB7 units, while the CB8 prefers the central site to be capped with two b-CD units.Internal Founding Agency of Tomas Bata University in Zlin [IGA/FT/2016/001]; Czech Science Foundation [16-05691S

Rotaxanes Capped with Host Molecules: Supramolecular Behavior of Adamantylated Bisimidazolium Salts Containing a Biphenyl Centerpiece

Bisimidazolium salts with one central biphenyl binding site and two terminal adamantyl binding sites form water-soluble binary or ternary aggregates with cucurbit[7]uril (CB7) and β-cyclodextrin (β-CD) with rotaxane and pseudorotaxane architectures. The observed arrangements result from cooperation of the supramolecular stopper binding strength and steric barriers against free slippage of the CB7 and β-CD host molecules over the bisimidazolium guest axle. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.internal funding agency of Tomas Bata University in Zlin [IGA/FT/2015/005]; program "Projects of Large Infrastructure for Research, Development, and Innovations" [LM2010005

Cooperative binding of cucurbit[n]urils and β-cyclodextrin to heteroditopic imidazolium-based guests

Imidazolium-based guests containing two distinct binding epitopes are capable of binding beta-cyclodextrin and cucurbit[6/7]uril (CB) simultaneously to form heteroternary 1:1:1 inclusion complexes. In the final the hosts occupy binding sites disfavored in the binary complexes because of the chemically induced reorganization of the intermediate 1:1 aggregate. In addition, the reported guests are capable of binding two CBs to form either 1:2 or 1:1:1 ternary assemblies despite consisting of a single cationic moiety. Whereas the adamantane site binds CB solely via hydrophobic interactions, the CB unit at the butyl site is stabilized by a combination of hydrophobic and ion-dipole interactions.Internal Funding Agency of Tomas Bata University in Zlin [IGA/FT/2016/001]; Czech Science Foundation [16-05961S]; Ministry of Education, Youth and Sports of the Czech Republic under Project CEITEC [LQ1601]; CERIT Scientific Cloud under the program "Projects of Large Research, Development, and Innovations Infrastructures" [LM2015085

Novel adamantane-bearing anilines and properties of their supramolecular complexes with β-cyclodextrin

Several novel anilines bearing 1-adamantyl substituents that are useful for drug modification were synthesised from the corresponding 1-adamantyl (nitrophenyl) ketones. The host-guest systems of these prepared ligands with β-cyclodextrin (β-CD) were studied using electrospray ionisation mass spectrometry, NMR spectroscopy, titration calorimetry and semiempirical calculations. The complexes with 1:1 stoichiometry were found to predominantly exist as pseudorotaxane-like threaded structures with the adamantane cage sitting deep in the cavity of β-CD close to the wider rim. Such geometry was observed for all examined amines and is independent of their structure and/or presence of protic substituents. © 2011 Taylor & Francis