Supramolecular Chemistry and Self-Assembly
From intermolecular forces to function
Noncovalent interactions
Hydrogen bonding, halogen bonding, -stacking, electrostatics, induction, and dispersion collectively shape supramolecular structure. These interactions are individually weak but collectively powerful, particularly in large assemblies and biological recognition.
Design principle
Selectivity often comes from matching geometry, polarity, and desolvation penalties rather than maximizing binding energy alone.
Thermodynamics of binding
Binding free energy is governed by A favorable enthalpy can be offset by large entropic costs from conformational restriction or solvent reorganization.
Which term best captures the energetic contribution of dispersion-dominated aromatic association?
Dispersion is the attractive correlation effect important in stacking and hydrophobic association.
Correct answer: London dispersion
What is guest selectivity in host-guest chemistry?
Selectivity underlies sensing, separations, and molecular recognition.
Correct answer: The preference of a host to bind one guest more strongly or more rapidly than competing guests.
Common supramolecular motifs
| Motif | Characteristic feature | Use |
|---|---|---|
| Cyclodextrins | Hydrophobic cavity | Drug delivery and recognition |
| Crown ethers | Cation binding | Ion transport and sensing |
| Cages and capsules | Encapsulation | Stabilization of reactive species |
| MOFs/COFs | Extended porosity | Separation, storage, catalysis |
Thermodynamic vs kinetic control
Thermodynamic control
- Most stable assembly dominates
- Sensitive to equilibrium conditions
- Useful for error correction
Kinetic control
- Fastest-forming product dominates
- Depends on pathway and mixing
- Useful for trapping metastable structures
Why can solvent effects reverse host-guest preferences?
Solvent can stabilize or penalize binding partners differently, altering .
Correct answer: Because desolvation and competition for interactions can change free energies
Emerging directions
Research frontiers include dissipative self-assembly, adaptive and out-of-equilibrium materials, allosteric molecular recognition, and using supramolecular architectures as programmable reaction environments.