Scavenging sunblock agents from aquatic environment through encapsulation in cucurbit[7]uril.

Area of Science:

• Computational Chemistry
• Supramolecular Chemistry
• Environmental Science

Background:

• Organic UV filters are widely used but can pose ecological risks.
• Cucurbiturils are macrocyclic hosts with potential for molecular encapsulation.
• Understanding host-guest interactions is crucial for developing safer UV protection strategies.

Purpose of the Study:

• To investigate the encapsulation of six organic UV filters by Cucurbit[7]uril (CB[7]).
• To evaluate the thermodynamic stability and interaction mechanisms of these host-guest complexes.
• To assess the potential of CB[7] for mitigating the environmental impact of UV filters.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Analyses included interaction energy, Non-Covalent Interaction (NCI), Quantum Theory of Atoms in Molecule (QTAIM), Frontier Molecular Orbital (FMO), Density of States (DOS), and Natural Bond Orbital (NBO).
• Recovery time and desorption energy were also computed.

Main Results:

• CB[7] demonstrated thermodynamic stability in encapsulating UV filters, with interaction energies from -11.78 to -20.42 kcal/mol.
• Van der Waals interactions were predominant, confirmed by NCI and QTAIM analyses.
• Complexation decreased energy gaps and induced charge transfer from CB[7] to UV filters, notably for oxybenzone@CB[7].
• Dioxybenzone@CB[7] showed the strongest adsorption and longest recovery time, suggesting high stability.

Conclusions:

• CB[7] is an effective host for encapsulating organic UV filters.
• The study provides insights into the binding mechanisms and stability of CB[7]-UV filter complexes.
• This research offers a promising avenue for reducing the negative ecological effects of organic UV filters.