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The Role of Packing, Dispersion, Electrostatics, and Solvation in High‐Affinity Complexes of Cucurbit[ n ]urils with Uncharged Polar Guests
Author(s) -
Grimm Laura M.,
Spicher Sebastian,
Tkachenko Boryslav,
Schreiner Peter R.,
Grimme Stefan,
Biedermann Frank
Publication year - 2022
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202200529
Subject(s) - solvation , chemistry , dispersion (optics) , binding energy , polar , electrostatics , selectivity , supramolecular chemistry , crystallography , computational chemistry , stereochemistry , chemical physics , materials science , molecule , organic chemistry , crystal structure , atomic physics , physics , astronomy , optics , catalysis
The rationalization of non‐covalent binding trends is both of fundamental interest and provides new design concepts for biomimetic molecular systems. Cucurbit[ n ]urils (CB n ) are known for a long time as the strongest synthetic binders for a wide range of (bio)organic compounds in water. However, their host‐guest binding mechanism remains ambiguous despite their symmetric and simple macrocyclic structure and the wealth of literature reports. We herein report experimental thermodynamic binding parameters (Δ G , Δ H , TΔ S ) for CB7 and CB8 with a set of hydroxylated adamantanes, di‐, and triamantanes as uncharged, rigid, and spherical/ellipsoidal guests. Binding geometries and binding energy decomposition were obtained from high‐level theory computations. This study reveals that neither London dispersion interactions, nor electronic energies or entropic factors are decisive, selectivity‐controlling factors for CB n complexes. In contrast, peculiar host‐related solvation effects were identified as the major factor for rationalizing the unique behavior and record‐affinity characteristics of cucurbit[ n ]urils.