Binuclear species

Fenton. The maximum performance is usually observed at pH slightly below 3 because of two reasons (i) colloids that begin to precipitate at pH above 3 via the binuclear species (Q 2,2) are suppressed and (ii) the concentration of Fe(OH) ( i) is close to its maximum. Fe(OH ) species possess a high absorption coefficient under irradiation and maximize the oxidation yield. This holds for diluted systems. When the total Fe concentration is increased, the binuclear species become dominant and precipitation is favored. Figure 6.3b clarifies this aspect by showing the Fe2(OH)2 + concentration profiles for increasing Fe concentrations. In those cases, lowering the pH to about 2 is favorable. 

Mode of formation Binuclear species Specific decomposition rate at 25.0 °C (sec ) log k for formation of SCN complex Ref... 

That HCr04, VO and VO2 are the predominant species under the conditions of Espenson s kinetic study originates from evidence cited by Tong and King, and Rossotti and Rossotti, respectively. No binuclear species are detectable in the Cr(III) product. Vanadium(V) retards the reaction and the full form of the rate law is... 

The redox reactions of the actinide elements have been the subject of a recent and authoritative review by Newton and Baker . The net activation process concept is used to interpret the experimental data. Empirical correlations shown to exist include those between the entropies of the activated complexes and their charges, and, for a set of similar reactions, between AG and AG , and and A/f . The present state of the evidence for binuclear species is discussed. 

The binuclear species (69) and (70) are prepared from the reaction of [Ir(PEt3)2(C2H4)2Cl] with liquid NH3, followed by treatment with NaBPh4 or pyridine, respectively. Both structures are determined by X-ray crystallography and show Ir—Ir distances of 3.33 A and 3.34 A, respectively.94... 

The yellow, air-stable, binuclear species [Ir(OMe)(cod)]2 is a useful precursor in Ir alkoxy chemistry and may be prepared according to reaction Scheme 41.627... 

Reaction of [Ir(cod)Cl]2 with (6-methyl-2-pyridyl)methyl lithium yields the binuclear species [(cod)Ir(/i-CH2-py-6-Me-C, /V)]2, (401). The Ir centers in (401) are 3.5889(3) A apart, indicating little metal-metal interaction. Treatment of (401) with PPh2Et yields [(cod)Ir(PPh2Et)2(CH2-py-6Me)], which contains the monodentate, carbon-bound pyridylmethyl ligand. 

G.A. Ozin, University of Toronto In our Cr/CO matrix cocondensation experiments (Angew. Chem., Int. Ed. Eng. 1975, 14, 292), we reported evidence for the facile formation of a binuclear chromium carbonyl complex Cr2(CO)i0 or Cr2 (CCOi x which could be described as square pyramidal Cr(CO)5 weakly interacting with either a Cr(CO)5 or Cr(CO)6 moiety in the vacant (sixth) site. As a result, the infrared spectrum of this "weakly-coupled" binuclear species closely resembled that of the mononuclear fragment Cr(CO)5. I would like to ask you, whether or not you have any evidence for the existence of such a binuclear species in your Cr(CO)6 /Xe cryogenic solutions following various photolysis treatments. 

Some representative systems. A further type of binuclear species incorporates two metal ions bridged by one or two small groups within the macrocyclic ring. Such complexes differ from the previous type in that the bridges between the metal ions do not involve donor groups which are directly attached to the macrocycle - see (122) and (123). A variety of... 

A detailed kinetie study in the Fenton chemistry, based on spectrophotometric measurements of evolved O2 and the disappearance of Fe, has shown the existence of a new intermediate Kremer 1999). It was identified as the mixed valence binuclear species... 

The binuclear species can react with H2O2 to form O2 and a mixture of Fe /Fe, according to ... 

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