Charge-transfer complexation between methylviologen and sacrificial electron donors EDTA, triethanolamine, and cysteine

Journal Article · Thu Nov 08 04:00:00 EST 1984 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j150667a041· OSTI ID:5894105

Prasad, D R; Hoffman, M Z

Methylviologen dication (MV/sup 2 +/) forms charge-transfer (CT) complexes with EDTA, triethanolamine (TEOA), and cysteine (Cys) in aqueous solution. The complexes of EDTA and TEOA show enhanced tail absorption from 320 nm well into the visible region; the Cys complex shows a discrete absorption band in the 350-380-nm region. By use of the Benesi-Hildebrand and other treatments for the variations of the absorbances of the complexes with the concentrations of the components, values of K/sub eq/ and epsilon/sub lambda/ for the complexes are obtained as functions of pH. Values of K/sub eq/ range from 0.29 M/sup -1/ for the Cys complex at pH 3.5 to 18 M/sup -1/ for the EDTA complex at pH 11.2; K/sub eq/ values are significantly higher in alkaline solution where the deprotonated donors are better reducing agents. The emission at 525 nm observed in these and other MV/sup 2 +/ systems is believed to arise from a highly luminescent impurity, not a CT complex. The ramifications of CT complex formation on the photochemistry of systems containing MV/sup 2 +/ and sacrificial electron donors are discussed. 57 references, 4 figures, 1 table.

• Research Organization: Boston Univ., MA
• OSTI ID: 5894105
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 88:8; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ABSORPTION SPECTROSCOPY
ALCOHOLS
AMINES
AMINO ACIDS
AQUEOUS SOLUTIONS
AZINES
BIPYRIDINES
CARBOXYLIC ACIDS
CHELATING AGENTS
CHEMICAL REACTIONS
COMPLEXOMETRY
CORRELATIONS
CYSTEINE
DATA
DISPERSIONS
EDTA
EMISSION SPECTROSCOPY
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EQUILIBRIUM
EXCITATION
EXCITED STATES
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
INFORMATION
IONIZATION
MATHEMATICAL MODELS
MATHEMATICS
MIXTURES
NUMERICAL ANALYSIS
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PH VALUE
PHOTOIONIZATION
PYRIDINES
SOLUTIONS
SPECTROSCOPY
STRUCTURAL CHEMICAL ANALYSIS
THIOLS
VIBRATIONAL STATES