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Spatiotemporally Controlled Nuclear Translocation of Guests in Living Cells Using Caged Molecular Glues as Photoactivatable Tags
Published on: January 17, 2019
Guest exchange dynamics in an M4L6 tetrahedral host
Anna V Davis1, Dorothea Fiedler, Georg Seeber
1Department of Chemistry, University of California, Berkeley, 94720-1460, USA.
Journal of the American Chemical Society
|January 26, 2006
Summary
This study defines the host-guest kinetic behavior of a [Ga(4)L(6)](12-) supramolecular capsule. Guest exchange occurs via a nonrupture mechanism, with rates influenced by guest concentration and host flexibility.
Area of Science:
- Supramolecular Chemistry
- Coordination Chemistry
- Materials Science
Background:
- M(4)L(6) supramolecular assemblies facilitate guest exchange through a nonrupture mechanism.
- The [Ga(4)L(6)](12-) assembly, with L = 1,5-bis(2',3'-dihydroxybenzamido)naphthalene, serves as a model system for studying host-guest dynamics.
Purpose of the Study:
- To define the host-guest kinetic behavior of the [Ga(4)L(6)](12-) supramolecular capsule.
- To elucidate the mechanism of guest exchange, including activation parameters and the influence of guest concentration and host flexibility.
Main Methods:
- Guest self-exchange rates were measured at varied temperatures and pressures.
- Activation parameters (DeltaH, DeltaS, DeltaV) were determined for different tetraalkylammonium guests.
- Guest displacement reactions were analyzed to assess the impact of guest binding affinities and concentrations.
Main Results:
- Negative DeltaS and positive DeltaV values were observed, indicating a constrained transition state and increased volume during guest exchange.
- Egress of the initial guest was rate-determining in PEt(4)(+) for NEt(4)(+) exchange.
- Increasing guest concentrations inhibited exchange due to decreased host flexibility from exohedral interactions, which could be overcome by blocking exohedral sites.
Conclusions:
- Guest exchange in the [Ga(4)L(6)](12-) assembly is sensitive to guest concentration, host flexibility, and thermodynamic binding affinities.
- Exohedral guest interactions significantly influence host dynamics and guest exchange rates.
- Understanding these kinetics is crucial for designing functional supramolecular materials.
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