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Updated: Jun 6, 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
8.1K
Structures of hexamethyl-[1,1'-biphenyl]-4,4'-diammonium salts
Rajakumar Kanthapazham1, Artyom A Osipov1, Dmitry A Zherebtsov1
1South Ural State University, Lenin prospekt 76, Chelyabinsk, 454080, Russian Federation.
Summary
This study details the crystal structures and thermal decomposition of nine hexamethyl-[1,1'-biphenyl]-4,4'-diammonium (HMB) salts. These water-soluble compounds exhibit distinct thermolysis mechanisms, including water loss and methyl group elimination.
Area of Science:
- Crystal engineering and materials science.
- Supramolecular chemistry.
- Organic and inorganic salt synthesis.
Background:
- Hexamethyl-[1,1 '-biphenyl]-4,4 '-diammonium (HMB) salts are known for their unique structural properties.
- Understanding the crystallization and thermal behavior of these salts is crucial for their application in materials science.
Purpose of the Study:
- To describe the crystal structures of nine novel HMB salts and one related compound.
- To investigate the thermal decomposition mechanisms of selected HMB salts.
- To explore the potential of HMB carbonate as an intermediate for anti-metal-organic frameworks.
Main Methods:
- Single-crystal X-ray diffraction for structural determination.
- Synchronous thermal analysis (thermogravimetry-differential scanning calorimetry) for thermolysis studies.
- Synthesis and characterization of HMB salts and related compounds.
Main Results:
- Detailed crystal structures of nine HMB salts, including iodide, triiodide, succinate, fumarate, tetravanadate, hydroterephthalate, perylenetetracarboxylate, and a metal-organic framework, are presented.
- HMB carbonate was synthesized as a precursor for anti-metal-organic frameworks.
- All compounds showed high water solubility, with crystallohydrates forming during crystallization.
- Compounds 6 (tetravanadate) and 9 (metal-organic framework) exhibit rigid framework structures, with compound 6 featuring an open framework filled with water.
- Thermolysis studies revealed consistent mechanisms: initial loss of crystallization water (80-180°C), followed by methyl group elimination to form tetramethylbenzidinium (180-250°C), and subsequent evaporation of tetramethylbenzidinium (240-355°C).
- Specific decomposition products for iodides and organic acid salts include methyl iodide and dimethyl carbonate.
Conclusions:
- The study provides comprehensive structural and thermal data for a series of HMB salts.
- The findings highlight the predictable thermolysis pathways of these quaternary ammonium salts.
- The synthesized HMB carbonate shows promise for developing new anti-metal-organic framework materials.
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