Solid deposits of osmium bis-bipyridyl triazole chloride: Redox properties and electrocrystallisation

被引:10
作者
Forster, RJ [1 ]
Keyes, TE
机构
[1] Dublin City Univ, Sch Chem Sci, Natl Ctr Sensor Res, Dublin 9, Ireland
[2] Dublin Inst Technol, Sch Chem, Dublin 8, Ireland
关键词
D O I
10.1039/b008027f
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Mechanically attached, solid-state films of [Os(bpy)(2) bpt Cl] have been formed on platinum microelectrodes and their voltammetric properties investigated, bpy is 2,2'-bipyridyl and bpt is 3,5-bis(pyridin-4-yl)-1,2,4-triazole. Scanning electron microscopy reveals that voltammetric cycling in 1.0 M HClO4 converts the amorphous array of microscopically small particles into a plate-like semi-crystalline form. In contrast, crystallisation does not occur when the films are cycled in 1.0 M NaClO4. In both electrolytes, the voltammetric response of these films is reminiscent of that observed for an ideal reversible, solution phase redox couple. Slow and fast scan linear sweep voltammograms have been used to provide an absolute determination of the fixed site concentration and apparent diffusion coefficient, D-app. The fixed site concentration is 1.65 +/-0.05 M for films cycled in either electrolyte and the D-app values increase with increasing electrolyte concentration, C-elec. These observations suggest that ion transport rather than the rate of electron self-exchange limit the overall rate of charge transport through these solids. In 1.0 M NaClO4, D-app values for oxidation and reduction are identical at 8.3 +/-0.5x10(-12) cm(2) s(-1). In 1.0 M HClO4, D-app is significantly lower and depends on whether the deposit is being oxidised (9.7 +/-0.4x10(-13) cm(2) s(-1)) or reduced (6.3 +/-0.4x10(-13) cm(2) s(-1)). These data have been used to obtain an insight into the relative importance of intra- vs. inter-particle charge transport. When C-elec>0.5 M, the standard heterogeneous electron transfer rate constant, k degrees, becomes independent of the electrolyte concentration with a value of 1.7 +/-0.2x10(-5) cm s(-1) being observed in both 1.0 M NaClO4 and HClO4. Significantly, the distance normalised heterogeneous electron transfer rate constant for these solid state films is almost three orders of magnitude smaller than that found within a spontaneously adsorbed monolayer of the same complex. The importance of these results for the rational design of solid-state redox active materials for battery, display and sensor applications is considered.
引用
收藏
页码:1336 / 1344
页数:9
相关论文
共 43 条
[1]   THEORY OF LINEAR SWEEP VOLTAMMETRY WITH FINITE DIFFUSION SPACE [J].
AOKI, K ;
TOKUDA, K ;
MATSUDA, H .
JOURNAL OF ELECTROANALYTICAL CHEMISTRY, 1983, 146 (02) :417-424
[2]  
Bard A. J., 1980, ELECTROCHEMICAL METH
[3]   The relationship between the electrochemistry and the crystallography of microcrystals. The case of TCNQ (7,7,8,8-tetracyanoquinodimethane) [J].
Bond, AM ;
Fletcher, S ;
Symons, PG .
ANALYST, 1998, 123 (10) :1891-1904
[4]   MECHANISTIC ASPECTS OF THE ELECTRON AND ION-TRANSPORT PROCESSES ACROSS THE ELECTRODE SOLID SOLVENT (ELECTROLYTE) INTERFACE OF MICROCRYSTALLINE DECAMETHYLFERROCENE ATTACHED MECHANICALLY TO A GRAPHITE ELECTRODE [J].
BOND, AM ;
MARKEN, F .
JOURNAL OF ELECTROANALYTICAL CHEMISTRY, 1994, 372 (1-2) :125-135
[5]   Novel features associated with the electrochemically driven bis(η5-pentaphenylcyclopentadienyl)iron(II)-iron(III) redox transformation at an electrode-microcrystal-solvent (electrolyte) interface [J].
Bond, AM ;
Lamprecht, A ;
Tedesco, V ;
Marken, F .
INORGANICA CHIMICA ACTA, 1999, 291 (1-2) :21-31
[6]   Unusually fast electron and anion transport processes observed in the oxidation of "electrochemically open" microcrystalline [{M(bipy)2}{M′(bipy)2}(μ-L)](PF6)2 complexes (M, M′ = Ru, Os; bipy=2,2′-bipyridyl; L=1,4-dihydroxy-2,5-bis(pyrazol-1-yl)benzene dianion) at a solid-electrode-aqueous electrolyte interface [J].
Bond, AM ;
Marken, F ;
Williams, CT ;
Beattie, DA ;
Keyes, TE ;
Forster, RJ ;
Vos, JG .
JOURNAL OF PHYSICAL CHEMISTRY B, 2000, 104 (09) :1977-1983
[7]   RATE OF ELECTRON EXCHANGE BETWEEN IRON, RUTHENIUM, AND OSMIUM COMPLEXES CONTAINING 1,10-PHENANTHROLINE, 2,2'-BIPYRIDYL, OR THEIR DERIVATIVES FROM NUCLEAR MAGNETIC-RESONANCE STUDIES [J].
CHAN, MS ;
WAHL, AC .
JOURNAL OF PHYSICAL CHEMISTRY, 1978, 82 (24) :2542-2549
[8]   KINETICS OF LATERAL ELECTRON HOPPING IN OSMIUM-TRIS-4,7-DIPHENYLPHENANTHROLINE PERCHLORATE MONOLAYERS AT THE AIR-WATER-INTERFACE [J].
CHARYCH, DH ;
ANVAR, DJ ;
MAJDA, M .
THIN SOLID FILMS, 1994, 242 (1-2) :1-6
[9]   ELECTROCHEMICAL INVESTIGATIONS OF THE LATERAL DIFFUSION AND ELECTRON HOPPING IN LANGMUIR MONOLAYERS AT THE AIR-WATER-INTERFACE [J].
CHARYCH, DH ;
MAJDA, M .
THIN SOLID FILMS, 1992, 210 (1-2) :348-351
[10]   ELECTROACTIVE POLYMERS AND MACROMOLECULAR ELECTRONICS [J].
CHIDSEY, CED ;
MURRAY, RW .
SCIENCE, 1986, 231 (4733) :25-31