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Updated: Jun 25, 2025
Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
D 4h H©K4H4-: a planar tetracoordinate hydrogen global minimum
Li-Xia Bai1, Yan-Xia Jin1, Jin-Chang Guo1
1Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China. guojc@sxu.edu.cn.
Researchers discovered a stable square-like anion, H©K₄H₄⁻, featuring a unique planar tetracoordinate hydrogen (ptH) center. This finding challenges traditional bonding models and highlights novel hydrogen bonding interactions in inorganic chemistry.
Area of Science:
- Inorganic Chemistry
- Computational Chemistry
- Quantum Chemistry
Background:
- Traditional chemical bonding models primarily involve two-center, two-electron bonds.
- The existence and stability of polycoordinate hydrogen atoms remain an area of active research.
- Exploring novel bonding motifs can expand our understanding of chemical structures and reactivity.
Purpose of the Study:
- To report the discovery and characterization of a novel square-like anion, H©K₄H₄⁻.
- To investigate the structural and electronic properties of a planar tetracoordinate hydrogen (ptH) center.
- To elucidate the bonding nature and stability factors of this unique chemical species.
Main Methods:
- High-level quantum chemical calculations were employed to determine the structure and stability.
- Analysis of electron distribution and bonding characteristics using methods like Natural Bond Orbital (NBO) analysis.
- Vibrational frequency calculations to confirm dynamic stability and the nature of the potential energy surface.
Main Results:
- A square-like D₄h H©K₄H₄⁻ anion was identified as the global minimum structure.
- The central hydrogen atom is planar and tetracoordinate (ptH), stabilized by multicenter bonding.
- The structure is maintained by four peripheral K-H-K three-center two-electron (3c-2e) σ bonds and one central 5c-2e σ bond.
- Dynamic stability was confirmed through vibrational analysis.
Conclusions:
- The H©K₄H₄⁻ anion represents a significant finding in the study of polycoordinate hydrogen.
- Multicenter ionic bonds are the primary contributors to the stability of the planar tetracoordinate hydrogen center.
- The contribution of σ aromaticity to the stability of this system is minimal.
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