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Electron transfer reaction of electrochemically polymerized tris‐(amino‐phenanthroline)‐iron(II/III) complex films
Author(s) -
Kitagawa Mako,
Iwaku Masahiro,
Oyama Noboru
Publication year - 1995
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.1995.220060316
Subject(s) - propylene carbonate , acetonitrile , electrochemistry , electron transfer , materials science , phenanthroline , diffusion , redox , reaction rate constant , inorganic chemistry , electrode , analytical chemistry (journal) , kinetics , chemistry , organic chemistry , physics , quantum mechanics , metallurgy , thermodynamics
New films of iron complex with 4,7‐bis(2‐aminophenyl)‐methylaminosulfonylphenyl)‐1,10‐phenanthroline (APP) and 5‐amino‐1,10‐phenanthroline (AP) are prepared on the electrode surface of In–Sn oxide conducting glass (ITO) by electrochemical oxidation. The thickness (Φ) of the films prepared on the ITO can be controlled by the number of cycles of the potential scan. The resulting film‐coated electrodes show well‐defined reversible vol‐tammograms corresponding to the redox reaction of the Fe(II/III) complexes in 0.1 M NaClO 4 acetonitrile (AN), a mixture of butylene carbonate (BC) and propylene carbonate (PC) and poly2‐hydroxyethylmethacrylate gel containing BC and PC. The electron transfer processes within the films can be treated apparently as diffusional processes characterized by the rate constants of the apparent diffusion coefficient (D app ). The value of D app increase from 1.0 × 10 −9 to 1.6 × 10 −8 cm 2 sec −1 as the Fe complex concentration (C Fe ) increases from 0.06 to 1.04 M for the [Fe(AP) 3 ] complex film (Φ=0.80 μm) in 0.2 M NaClO 4 /AN solution. The D app value for the [Fe(APP) 3 ) complex film (C Fe = 0.19 M , Φ= 0.78 μm) is 3.5 × 10 −9 cm 2 sec −1 in 0.2 M NaClO 4 /AN solution. The D app values of the [Fe(AP) 3 ] complex film in the PC + BC mixture and gel containing 1.0 M NaClO 4 were smaller than those obtained in AN solution by an order of magnitude. The dependence of the apparent formal potential of the Fe(II/III) redox reaction for the [Fe(AP) 3 ] complex film on the activity of NaClO 4 supporting electrolyte in AN shows that Na + moves preferentially across the polymer/solution interfaces during the redox reaction. The Fe(II/III) redox reaction of the Fe complex films shows reversible electrochromic response between red and colorless.