Redox-conducting metal complex

II. BOTTOM-UP FABRICATION OF REDOX-CONDUCTING METAL COMPLEX OLIGOMERS ON AN ELECTRODE SURFACE AND THEIR REDOX CONDUCTION BEHAVIOR 389... 

III. PHOTOELECTRIC CONVERSION SYSTEM USING PORPHYRIN AND REDOX-CONDUCTING METAL COMPLEX WIRES 401... 

In this chapter, we describe three different systems with which to construct electro- and photo-functional molecular assemblies on electrode surfaces. The first is the bottom-up fabrication of redox-conducting metal complex oligomers on an electrode surface and their characteristic redox conduction behavior, distinct from conventional redox polymers.11-13 The second is a photoelectric conversion system using a porphyrin and redoxconducting metal complex.14 The third is the use of a cyanobacterial photosystem I with molecular wires for a biophotosensor and photoelectrode.15 16 These systems will be the precursors of new types of molecular devices working in electrolyte solution. 

A. Bottom-Up Fabrication of the Porphyrin-Terminated Redox-Conducting Metal Complex Film on ITO... 

Earlandite structure, 849 Electrical conductivity metal complexes, 133 tetracyanoplatinates anion-deficient salts, 136 Electrical properties metal complexes, 133-154 Electrocatalysis, 28 Electrochemical cells, 1 Electrochemistry, 1-33 hydrogen or oxygen production from water coordination complex catalysts, 532 mineral processing, 831 reduction, 831 Electrodeposi (ion of metals, 1-15 mineral processing difficulty, 831 Electrodes clay modified, 23 ferrocene modified, 20 nation coated, 15 polymers on, 16 polyvinylferrocene coated, 19 poly(4-vinylpyridine) coated, 17 redox centres, 17 Prussian blue modified, 21 surface modified, 15-31 Electrolysis... 

In the last decade, there has been a large number of reports on synthetic macro-molecule-metal complexes concerning their complexation, catalytic activities, redox reactions, adsorptions of gaseous molecules and metal ions, photochemical behavior, biochemical effects, modified electrodes, semiconductive and conductive materials, and so on. 

While molecular assembly has proven to be effective for a photoelectric conversion system, coordination reactions are possibly a simple approach for connecting such functional molecules, as presented in the previous section. We applied the stepwise coordination method to prepare a photoelectric conversion system. Since the molecular wire exhibits redox conduction through the wire,11,13 efficient photo-electron transport through the redox sites in the wire is also expected. In this section, we demonstrate the fabrication of a photoelectric conversion system using ITO electrodes modified with M(tpy)2 (M = Co, Fe, Zn) complex wires with a terminal porphyrin moiety as a photosensitizer. The behavior of photo-electron transfer from porphyrin to ITO through the molecular wire was investigated by changing the metal element in the M(tpy)2 moieties.14... 

Hybrid materials which combine the electronic conductivity of thiophene-conjugated polymers and the redox and optical properties of metal complexes are being developed to take advantage of synergistic electronic interactions. 

Most studies indicate that the metal has the greatest effect on the properties of the polymer when it is part of the backbone, rather than a sidegroup. The direct coupling of the metal orbitals with the Tr-orbitals of the conjugated polymer may allow redox-matching to enhance the conductivity and perturb the band structure of the polymer. However, it is often synthetically easier to add the metal center as a side chain of a known polymer (e.g., on PPV) than to develop new polymerization procedures for the metal complex. 

Electropolymerization represents a useful method to control precisely the deposition of thin films of conducting polymers. These thin films have a wide variety of applications in optical devices [29]. Walder and coworkers showed that photocurrents could be generated using a trilayer thin film. The three different electropolymerized polymers were cleverly prepared from a common precursor, 4-methyl-4 -(2-pyrrolyl-1 -ethyl)-2,2 -bipyridine 7 two were alkylated, diquat derivatives and one was the Ru metal complex of this ligand, which acted as a sensitizer. The appropriate ordering of the triad in terms of their redox potentials led to the maximizing of the photocurrent (Scheme 7.2) [30],... 

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