N-Arylimide Molecular Balances: A Comprehensive Platform for Studying Aromatic Interactions in Solution.
Ping Li1, Erik C Vik2, Ken D Shimizu3
1Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
Accounts of Chemical Research
|November 5, 2020
Summary
Molecular balances precisely measure weak aromatic interactions, revealing that charged groups form the strongest bonds, while electrostatics and solvent effects significantly influence stability.
Area of Science:
- Physical organic chemistry
- Supramolecular chemistry
- Materials science
Background:
- Noncovalent aromatic interactions are crucial in biology and materials science.
- Studying these weak interactions is challenging due to multiple modulating factors.
- Previous methods lacked a unified platform for diverse aromatic interaction studies.
Purpose of the Study:
- To establish and utilize N-arylimide molecular balances for quantifying weak aromatic interactions in solution.
- To systematically investigate various aromatic interactions, including stacking, cation-π, and halogen-π.
- To compare interaction energies, stability trends, and solvent effects across different interaction types within a single model system.
Main Methods:
- Utilized N-arylimide molecular balances to measure noncovalent interactions via conformational equilibrium.
- Varied the structure and nature of π-surfaces and interacting groups to study diverse interactions.
- Analyzed interaction energies, stability trends, and solvent effects using the molecular balance platform.
Main Results:
- Strongest interactions observed with positively charged groups (cation-π, metal-π) and partially positive groups.
- Electrostatic interactions are tunable from repulsive to attractive via substituents and heterocycles, applicable to halogen-π and chalcogen-π interactions.
- Nonpolar groups exhibit weak stabilizing interactions driven by dispersion and solvophobic effects, predictable by solvent-accessible surface area changes.
- Solvent effects, including solvophobic impacts and competitive solvation, significantly modulate interaction strengths.
Conclusions:
- N-arylimide molecular balances provide a versatile platform for comprehensive studies of weak aromatic interactions.
- Aromatic interaction strength is governed by electrostatics, substituent effects, and solvent properties.
- Understanding these factors is key for designing functional molecules and materials.
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