An effective simulation of aqueous micellar aggregates by computational models

Area of Science:

• Supramolecular Chemistry
• Computational Chemistry
• Physical Chemistry

Background:

• Cetyltrimethylammonium salts (CTAX) form micelles, crucial structures in various chemical and biological processes.
• Understanding the interaction of small molecules like benzene with micellar surfaces is key to controlling chemical reactions and drug delivery.
• Experimental Nuclear Magnetic Resonance (NMR) data provides insights into these interactions but requires computational interpretation.

Purpose of the Study:

• To computationally investigate the binding site, localization, and orientation of benzene (Bz) on CTAX micelle surfaces.
• To interpret experimental 1H-NMR data using computational modeling.
• To evaluate the effectiveness of simplified models for studying complex surfactant-solute interactions.

Main Methods:

• Utilized automatic molecular docking to predict benzene's position on CTAX micelles.
• Employed a computational module to calculate NMR complexation shifts, considering ring current diamagnetic anisotropy.
• Tested three distinct models of varying complexity to simulate the micellar system.

Main Results:

• Computational findings align well with experimental 1H-NMR data.
• Benzene molecules preferentially localize along the CTAX alkyl tail, approximately 3.9 angstroms from the nitrogen atom.
• The predicted orientation shows the benzene molecular plane perpendicular to the alkyl tail's C-H bonds.

Conclusions:

• The study successfully models benzene-CTAX micelle interactions, confirming experimental observations.
• The simplest computational model proved effective, indicating its potential for studying more complex surfactant systems.
• This approach can be applied to surfactants with molecular recognition or catalytic properties.