Semiconductors metal complexes

Maeda, K. Sekizawa, K. Ishitani, O. A polymeric-semiconductor-metal-complex hybrid photocatalyst for visible-light C02 reduction. Chem. Commun., 2013, 49, 10127-10129. 

Tertiary stibines have been widely employed as ligands in a variety of transition metal complexes (99), and they appear to have numerous uses in synthetic organic chemistry (66), eg, for the olefination of carbonyl compounds (100). They have also been used for the formation of semiconductors by the metal—organic chemical vapor deposition process (101), as catalysts or cocatalysts for a number of polymerization reactions (102), as ingredients of light-sensitive substances (103), and for many other industrial purposes. 

Organic semiconductors are becoming increasingly important in the fabrication of electronic devices. For electron transport, metal complex pigments, such as hexa-deca-fluoro copper phthalocyanine (76), are showing potential.79... 

Solar energy with the short wave length range and long wave range can be utilized by photolysis and by pyrolysis, respectively. As for photolysis, we have (1) the biological area based upon the photosynthesis, and (2) the electrochemical area such as photoelectrochemical with photo semiconductor, with dye and metal complex etc. [13],... 

Coordination compounds composed of tetrapyrrole macrocyclic ligands encompassing a large metal ion in a sandwich-like fashion have been known since 1936 when Linstead and co-workers (67) reported the first synthesis of Sn(IV) bis(phthalocyanine). Numerous homoleptic and heteroleptic sandwich-type or double-decker metal complexes with phthalocyanines (68-70) and porphyrins (71-75) have been studied and structurally characterized. The electrochromic properties of the lanthanide pc sandwich complexes (76) have been investigated and the stable radical bis(phthalocyaninato)lutetium has been found to be the first example of an intrinsic molecular semiconductor (77). In contrast to the wealth of literature describing porphyrin and pc sandwich complexes, re-... 

Some transition metal complexes are excellent conductors. Thin films of cyto-chrome-C3, which contains four heme moieties coordinated by protein, exhibited a high conductivity with mixed valence state (Fe /Fe ) and showed an increase in conductivity as the temperature was decreased (2 x 10 S cm at 268 K) [68-70]. The temperature dependence of conductivity in the highly conductive region is the opposite of that of semiconductors and may preclude the ionic conduction as a dominant contribution. However, since the high conductivity is realized in the presence of hydrogenase and hydrogen, the system is not strictly a single but rather a multicomponent molecular solid. 

A metal complex Pt(bqd)2 exhibited an insulator-metal-semiconductor transition under pressure [72, 73]. A continuous color change was observed in bis (diphenylglyoximato)Pt(ll), Scheme 5 [81] under pressure and thus has been used as a pressure indicator. For these cases it is not clear that n-d orbital mixing is critical for the transport. 

Photo-electrochemical (PEC) processes can produce hydrogen in one step - splitting water by illuminating a water-immersed semiconductor with sunlight. There are two types of photo-electrochemical processes. The first uses soluble metal complexes as catalysts. When these complexes dissolve, they absorb solar energy and produce an electrical charge that drives the water splitting reaction. This process mimics photo-synthesis, however, currently there is minimal experience in this process. 

Polymers play important roles in water photolysis. For multi-electron processes, polymer supported metal colloids or colloidal polynuclear metal complexes are very useful as catalysts. Unstable semiconductors with a small bandgap which photolyse... 

Conductive polymers are useful semiconductors or coating materials to construct solar cells. A new photodiode is proposed to be made from a film of a polymer metal complex. Immobilized catalysts on polymers are used for solar energy storage systems. 

Heavier metal ions and metal complexes can find sites on nitrogen atoms of the nucleic acid bases. Examples are the platinum complex cisplatin and the DNA-cleaving antibiotic neocarzinostatin (Box 5-B). Can metals interact with the n electrons of stacked DNA bases A surprising result has been reported for intercalating complexes of ruthenium (Ru) and rhodium (Rh). Apparent transfer of electrons between Ru (II) and Rh (III) over distances in excess of 4.0 nm, presumably through the stacked bases, has been observed,181 as has electron transfer from other ions.181a Stacked bases are apparently semiconductors.182... 

Another important and well studied paramagnetic ion in the lattice of oxide semiconductors is Zr3+ in Zr02. Zirconia dioxide is widely used both as a catalyst of different chemical processes, and as a carrier for constructing supported metal-complex catalysts. In the last years, sulfated zirconia attracted significant interest as an active and selective catalyst in skeletal isomerization of normal alkanes at low temperatures, cracking of paraffins, alkylation and acylation of aromatics [42, 53 and Refs therein]. The appropriate experimental data are collected in the following Table 8.2. 

Kokorin, Alexander I, was bom in 1947. Was graduated as a biophysicist in 1970 Ph.D. (Candidate of Sciences) in 1974 D.Sc. degree (Doctor of Sciences) in physical chemistry - in 1992. At present Principal Researcher and Deputy Head of the Division of Kinetics and Catalysis, N. Semenov Institute of Chemical Physics of Russian Academy of Sciences, Moscow, Russia. Area of research interests chemical methods of solar energy conversion chemical physics of organized molecular systems, including nanosized oxide semiconductors doped with transition metal ions, and polymer-metal complexes the study of their structure, absorptive, catalytic, photocatalytic and photoelectrochemical properties. EPR spectroscopy and spin-spin interaction between paramagnetics. He is the author and co-author of more than 170 publications, including two books and several reviews and book chapters. 

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