Formation and stabilization of anionic metal complexes in concentrated aqueous quaternary ammonium salt solutions
Anionic complexes of transition metals were stabilized in aqueous solutions containing high concentrations of various short-chain quaternary ammonium salts. Compounds with longer paraffin chains were effective in much less concentrated solution. Complex ions were detected spectrophotometrically. FeCl/sub 4//sup -/, which is usually formed in concentrated HCl, was the predominant Fe(III) complex in 30 m choline chloride containing only 0.12 M HCl. A yellow transitory Tc(VII) chloro-addition intermediate, formed in the reduction of TcO/sub 4//sup -/ by concentrated HCl, was stabilized when the solution also contained 25 m choline chloride. Its spectrum, as well as the isolation of an already known Tc(VII) bipyridyl complex, is reported. Concentrated organic electrolytes also stabilized Tc(V) oxide halides against disproportionation and Tc(IV) hexahalides against hydrolysis. Halochromates of Cr(VI) were formed and stabilized in dilute acid containing quaternary ammonium salts. Their UV spectra showed the well-resolved vibronic fine structure associated with the symmetric chromium-to-oxygen charge-transfer band. It is known that these progressions are resolved in aprotic solvents, but not in aqueous acidic solution alone, and that the loss of fine structure in aqueous media is due to hydrogen bonding. The stabilization of anionic metal complexes and the resolution of vibronic structure in halochromates are probably consequences of water-structure-enforced ion paring. The present work suggests that the water molecules in immediate contact with the complex anions are more strongly hydrogen bonded to each other than to the complex. 21 references, 4 figures.
- Research Organization:
- State Univ. of New York Downstate Medical Center, Brooklyn
- OSTI ID:
- 5619365
- Journal Information:
- Inorg. Chem.; (United States), Vol. 24:4
- Country of Publication:
- United States
- Language:
- English
Similar Records
Biogeochemistry of Fe and Tc Reduction and Oxidation in FRC Sediment
Speciation of technetium in carbonate media under helium ions and γ radiation
Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANIONS
STABILIZATION
SYNTHESIS
CHLORIDES
CHROMIUM COMPLEXES
HALIDES
IRON COMPLEXES
TECHNETIUM COMPLEXES
AMMONIUM COMPOUNDS
AQUEOUS SOLUTIONS
CHEMICAL BONDS
ELECTROLYTES
EXPERIMENTAL DATA
FINE STRUCTURE
HYDROCHLORIC ACID
HYDROGEN
HYDROLYSIS
ORGANIC COMPOUNDS
REACTION INTERMEDIATES
SALTS
SPECTROPHOTOMETRY
ULTRAVIOLET SPECTRA
WATER
CHARGED PARTICLES
CHEMICAL REACTIONS
CHLORINE COMPOUNDS
COMPLEXES
DATA
DECOMPOSITION
DISPERSIONS
ELEMENTS
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
INFORMATION
INORGANIC ACIDS
IONS
LYSIS
MIXTURES
NONMETALS
NUMERICAL DATA
OXYGEN COMPOUNDS
SOLUTIONS
SOLVOLYSIS
SPECTRA
TRANSITION ELEMENT COMPLEXES
400702* - Radiochemistry & Nuclear Chemistry- Properties of Radioactive Materials
400201 - Chemical & Physicochemical Properties