Ionic hydrogen bond. 3. Multiple NH/sup +/. O and CH/sup delta//sup +/. O bonds. Complexes of ammonium ions with polyethers and crown ethers
Complexes of ammonium ions RNH/sub 3//sup +/ (R = methyl, c-cyclohexyl), trimethylammonium/sup +/ and pyridinium/sup +/ with polyethers and crown ethers were observed in the gas phase in the absence of solvent effects. The dissociation energies, ..delta..H/sub D//sup 0/ of the RNA/sub 3//sup +/ polyether complexes range from 29.4 kcal/mole (for RNH/sub 3/.dimethoxyethane) to 46 kcal/mole (RNH/sub 3//sup +/.18-crown-6). The large ..delta..H/sub D//sup 0/ values for complexes of polydentate ligands indicate multiple -NH/sup +/...O- hydrogen bonding. Such multiple bonding can contribute up to 18 kcal/mole to the bonding in RNH/sub 3//sup +/.triethyleneglycol dimethyl ether and 21 kcal/mole in RNH/sub 3//sup +/.18-crown-6. Total ..delta..H/sub D//sup 0/ values in the trimethylammonium/sup +/.polyether complexes range from 26.7 kcal/mole in trimethyl ammonium/sup +/.dimethoxyethane to 41 kcal/mole in trimethylammonium/sup +/.18-crown-6. Multiple interaction effects are observed in pyridineum/sup +/.polyether complexes. Large negative entropies in RNH/sub 3//sup +/.acyclic polyether complexes vs those of RNH/sub 3//sup +/.cyclic crown ethers make the acyclic polyethers less efficient ligands. 3 figures, 2 tables.
- Research Organization:
- National Bureau of Standards, Washington, DC
- OSTI ID:
- 5614807
- Journal Information:
- J. Am. Chem. Soc.; (United States), Vol. 105:15
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
AMINES
HYDROGENATION
STRUCTURAL CHEMICAL ANALYSIS
HYDROGEN
CHEMICAL REACTIONS
POLYETHYLENE GLYCOLS
AMMONIUM COMPLEXES
ENTHALPY
ENTROPY
EXPERIMENTAL DATA
GASES
HYDROGEN IONS 1 PLUS
MASS SPECTRA
MOLECULAR STRUCTURE
ALCOHOLS
CATIONS
CHARGED PARTICLES
COMPLEXES
DATA
ELEMENTS
FLUIDS
GLYCOLS
HYDROGEN IONS
HYDROXY COMPOUNDS
INFORMATION
IONS
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PHYSICAL PROPERTIES
POLYMERS
SPECTRA
THERMODYNAMIC PROPERTIES
400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)