Tuning the Binding Dynamics of a Guest–Octaacid Capsule through Noncovalent Anchoring

Abstract

Hydrophobic or hydrophilic substituents have different effects on the binding dynamics of pyrene derivatives with a 2:1 capsule formed from two octaacid cavitands, showing a subtle interplay of different kinetic factors. Anchoring of the methyl group of 1-methylpyrene within one cavitand slowed the association and dissociation dynamics of the 1:1 complex by at least 1,000 times when compared to the 1:1 complex for pyrene. This slow down for the transient formation of the 1:1 complex is responsible for the overall increase in stability of the 2:1 complex without affecting the overall capsule dissociation. For 1-pyrenemethanol, its residence time in the 2:1 capsule is shorter compared to pyrene despite both guests having similar equilibrium constants for the binding of the second cavitand, suggesting that the hydroxymethyl substituent close to the equatorial region of the capsule can interact with water during the partial opening of the capsule.

Hybrid material by anchoring a ruthenium(ii) imine complex to SiO2: preparation, characterization and DFT studies

“…The transition A 2 (d xy ) → A 2 (pπ * ) is less intense, which may be due to the overlapping of metal ion orbitals on XY axis and the ligand orbital A 2 (pπ*) ( Fig. 8 ) 3 as suggested earlier by Day and Sanders. 5,35–39 Meanwhile the interaction B 1 (d xz ) → B 1 (pπ * ) is of higher intensity and shorter wavelength because of main back donation, as expected.…”

“…1 Synthesis of these hybrid materials can be achieved via covalent or non-covalent immobilization of either organic or inorganic compounds on the solid support by encapsulation techniques, absorption, and covalent anchoring. [2][3][4][5] In particular, in the covalent immobilization of a coordination/ organometallic complex, the reactivity of the material may be inuenced by the functional groups that anchor the compound to the solid as reported by Silva et al 5 . Moreover, the anchored compound provides solubility to the hybrid material, suspending the solid in the solvent, whereas, the solid support contributes to the heterogeneous properties.…”

“…Hybrid materials syntheses by covalent anchoring are reported by two methodologies. [2][3][4][5] The rst one involves the anchoring of previously synthesized metal complex containing ligands with functional groups that react with the functionalized support active sites. The second methodology consists of constructing in situ the metallic complex, by functionalizing the solid support by a ligand, followed by the formation of the metallic complex.…”

“…Technological uses of hybrid materials are broad. For instance, materials synthesized by non-covalent anchoring of hydrophobic molecules contained in hydrophilic cages are applied in catalysis, drug delivery as reported by Gibb–Bohne et al 3 . Likewise, covalent anchoring is applied to synthetase catalytic materials.…”

Marcus Relationship Maintained During Ultrafast Electron Transfer Across a Supramolecular Capsular Wall

“…This and larger internal dimension allow inclusion of a wider variety of guest molecules . Importantly, the capsule is tight and takes a few milliseconds to partially open and close. , Therefore, during the time of electron transfer between the encapsulated excited donor and the acceptor, the capsule remains tightly closed similar to that of the Cram-type carcerand …”