Reversible oxidation and rereduction of entire thin films of transition-metal phthalocyanines
Thin films (1000 to 2000A thick) of iron(II) (Fe), cobalt(II) (Co), nickel(II) (Ni), copper(II) (Cu), and zinc(II) (Zr) phthalocyanines (Pc) on gold or indium oxide electrodes undergo stoichiometric oxidation and rereduction. Except for FePc and CoPc, the process is essentially reversible. Chronocoulometry showed that ZnPc films oxidized to the extent of 1.21 electrons per ZnPc molecule; CoPc required 1.92 electrons per molecule. Charge compensation is attained upon oxidation by uptake of anions from the electrolyte and by expulsion of anions upon reduction. Auger electron spectrometry allowed detection of the ions and characterization of their distributions. In partially oxidized films, the anions appear to be homogeneously distributed. Oxidation seems to proceed at all grains with equal probability, with anions entering and departing along grain boundaries. Smaller anions allow full oxidation at rapid rates; larger ones inhibit the oxidation with respect to rate. Optical spectroscopy showed evidence for reorganizaton of the crystalline lattices. The rereduced form is not the same as the original material, but it can be restored to the original form by annealing at 125/sup 0/C. In cyclic oxidations and rereductions, there is a gradual loss of charge-consuming ability, apparently related to electrical isolation of small domains, perhaps grains. The oxidations and rereductions are electrochromic, and the various color changes are described. 10 figures, 1 table.
- Research Organization:
- Univ. of Illinois, Urbana
- DOE Contract Number:
- AC02-76ER01198
- OSTI ID:
- 5904255
- Journal Information:
- J. Am. Chem. Soc.; (United States), Vol. 105:10
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
COBALT COMPLEXES
OXIDATION
REDUCTION
STRUCTURAL CHEMICAL ANALYSIS
COPPER COMPLEXES
IRON COMPLEXES
NICKEL COMPLEXES
ZINC COMPLEXES
AQUEOUS SOLUTIONS
AUGER ELECTRON SPECTROSCOPY
ELECTROCHEMISTRY
ELECTRODES
EXPERIMENTAL DATA
FILMS
GLASS
GOLD
HIGH VACUUM
INDIUM OXIDES
INFRARED SPECTRA
LIGANDS
PHOSPHORUS FLUORIDES
PHTHALOCYANINES
POTASSIUM FLUORIDES
PRESSURE DEPENDENCE
SAMPLE PREPARATION
ULTRAVIOLET SPECTRA
VAPOR DEPOSITED COATINGS
VISIBLE SPECTRA
VOLTAMETRY
ALKALI METAL COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
COATINGS
COMPLEXES
DATA
DISPERSIONS
DYES
ELECTRON SPECTROSCOPY
ELEMENTS
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HETEROCYCLIC COMPOUNDS
INDIUM COMPOUNDS
INFORMATION
METALS
MIXTURES
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
POTASSIUM COMPOUNDS
SOLUTIONS
SPECTRA
SPECTROSCOPY
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENTS
400201* - Chemical & Physicochemical Properties
400301 - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)
400400 - Electrochemistry
400104 - Spectral Procedures- (-1987)