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Updated: Sep 21, 2025
06:35
Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
8.2K
Tetramethylammonium Cation: Directionality and Covalency in Its Interactions with Halide Ions
Diego M Gil1, Jorge Echeverría1, Santiago Alvarez1
1Departament de Química Inorgànica i Orgànica and Institut de Química Teòrica i Computacional IQTC-UB, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain.
Inorganic Chemistry
|June 6, 2022
Summary
A new penetration index quantifies atomic interactions, revealing two energy minima for halogen-tetramethylammonium (TMA) cation pairs. This computational study highlights charge distribution variations and covalent character in interionic bonding.
Area of Science:
- Physical Chemistry
- Computational Chemistry
- Crystallography
Background:
- Nonbonding contact distances lack a standardized quantification method.
- Understanding intermolecular interactions is crucial in various chemical and physical processes.
Purpose of the Study:
- To introduce a "penetration index" for quantifying van der Waals crust interpenetration.
- To investigate structural trends and bonding mechanisms of tetramethylammonium (TMA) cation with halogen atoms (F, Cl, Br, I, Au).
Main Methods:
- Definition and application of a novel "penetration index".
- Computational study of model X···TMA ion pairs.
- Analysis of charge distribution and bonding mechanisms using established chemical tools.
Main Results:
- Identification of two distinct energy minima in the interaction between anions and the TMA cation.
- Anions were observed to interact simultaneously with three hydrogen atoms in each minimum.
- Charge distribution analysis revealed significant variations dependent on atomic identity and proximity to the central nitrogen atom.
Conclusions:
- The "penetration index" provides a robust metric for comparing interatomic contact distances.
- The study reveals complex bonding interactions, including non-negligible covalent character, not predicted by simple electrostatic models.
- The findings offer deeper insights into the nature of ion-molecule interactions involving TMA cations.
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