Redox reactions with atomic

Thiocarbamate (tc, RHNCSO-) is a monodentate ambidentate ligand, and both oxygen- and sulfur-bonded forms are known for the simple pentaamminecobalt(III) complexes. These undergo redox reactions with chromium(II) ion in water via attack at the remote O or S atom of the S- and O-bound isomers respectively, with a structural trans effect suggested to direct the facile electron transfer in the former.1045 A cobalt-promoted synthesis utilizing the residual nucleophilicity of the coordinated hydroxide in [Co(NH3)5(OH)]2+ in reaction with MeNCS in (MeO)3PO solvent leads to the O-bonded monothiocarbamate, which isomerizes by an intramolecular mechanism to the S-bound isomer in water.1046... 

The majority of inorganic reactions can be placed into one of two broad classes (1) oxidation-reduction (redox) reactions including atom and electron transfer reactions and (2) substitution reactions. Terms such as inner sphere, outer sphere, and photo-related reactions are employed to describe redox reactions. Such reactions are important in the synthesis of polymers and monomers and in the use of metal-containing polymers as catalysts and in applications involving transfer of heat, electricity, and light. They will not be dealt with to any appreciable extent in this chapter. 

Complicated internal redox reactions occur when atomic H is involved as a reducing agent. In quartz where the reduction of Ti4+ has been attributed to reactions with atomic H (21) Ti4+ + H + 02" = Ti3+ + OH , atomic H is stable only at low temperature (1). In brazilianites H may be responsible for the reduction of Fe3+ to Fe2+ plus OH (12.). Because H easily combines to H2 it becomes unreactive or escapes. The irreversibility of the redox reaction in brazilianites may be due to loss of H2. 

An example of the use of direct redox reactions in the preparation of bimetallic catalysts is the modification of copper catalysts by the addition of ruthenium, platinum, gold, or palladium [11-14], Assuming the metallic state for copper atoms on the surface, the redox reaction with the noble metal salts is... 

Redox reactions with FAD involve the transfer of two hydrogen atoms to the part of the molecule shown in green. Typical reactions of FAD involve dehydrogenations—as in double bond formation from single bonds. Of course, one of the H atoms can be transferred to FAD as a proton—only one need be a hydride ion H , though both could be transferred as radicals (H ). 

If empty zeolite LTA is exposed to cesium gas, and redox reaction with the exchangeable cations of the zeolite can occur, then the product Cs" " ions may seal the zeolite crystals. Everything within the zeolite may be encapsulated, including the product atoms, perhaps as neutral clusters. Well, nearly all cations, including Na" ", are reduced by Cs(g) only some of the other alkali-metal cations may resist reaction. Depending upon the mobility of the Cs" " ions at the reaction temperature, the surfaces of the crystals may be closed initially. If the reaction proceeds, the entire volume of the zeolite may be sealed. The ultimate outcome of the process will depend upon the mobilities of all the atoms and ions in the structure at the reaction temperature, and upon considerations of the stability and lability of any structural subunits which may form. 

Fig. 9.1 Time distribution of ( ) Cu ion and (o) Pt ion concentrations in solution during the preparation of Cu-Pt by direct redox reaction, with an initial atomic ratio Pt /Cus=57 (2g of Raney Cu, lOOmL of solution). Reprinted from C.

Electron-exchange reactions can be regarded as special cases of redox reactions, and in the given case, therefore, the parallel between the electron-exchange reaction of the iron ions and their redox reaction with the Ps atoms is obvious. 

Many inorganic atoms can undergo facile low-energy redox reactions. With the exception of quinones and flavins, this characteristic is in sharp contrast to classical organic... 

Reaction (3.II) is a reversible redox reaction with H+ residing in the electrolyte solution and the H atom on the Pt surface. If the entire Pt surface is completely covered by a monolayer of H atoms, the saturated surface concentration of Pt - can be expressed as Pp, (mol/cm ). If the Pt surface is not completely covered by Pt - the surface concentration of Pt -... 

The reaction of 2,3,4,5-tetrakis(trifluoromethyl)(yclopenta-2,4-dien-l-one with tertiary phosphines results in nucleophilic attack by the phosphine at carbonyl ojgrgen to form zwitterionic adducts. Nucleophilic attack at carbonyl ojgrgen is also implicated in a phosphine-mediated addition of 1,2-dicarbonyl compounds to nitroso-electrophiles. The diphosphine l,l-bis(diphenylphosphino)methane has been shown to undergo redox reactions with o-quinones, forming phosphine oxides of type (104). An overview of the reactions of HNO (azanone) with metal porphyrins includes reference to O-atom abstraction by phosphines from HNO to form nitrite. ... 

Fig. 8 Polyhedron and ball-and-stick representations of the [0 1 0] polyhedron chain exposed at the (0 0 1) surface in fabianite. The bonds (and corresponding bond-valences required) involving surface anions and constituents of the aqueous solution are shown as lines [bond valence donated from the (aquated) cations of the aqueous solution] and as arrows (bond valence draiated from H atoms of protonated surface anions to anions of the aqueous solutirm). Note that there are not many protonated anions that can participate in redox reactions with the aqueous solution...

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