Oxidation states usefulness

The amount of Fe in a 0.4891-g sample of an ore was determined by a redox titration with K2Cr20y. The sample was dissolved in HCl and the iron brought into the +2 oxidation state using a Jones reductor. Titration to the diphenylamine sulfonic acid end point required 36.92 mL of 0.02153 M K2Cr20y. Report the iron content of the ore as %w/w FeyOy. 

This latter reaction is most unusual in that it simultaneously involves an element (N) in four different oxidation states. Use of N-enriched reagents shows that all the N from HNO2 goes quantitatively to the internal N of N20 ... 

To test the generality of this reaction, the indole systems 70a,b were prepared from hexahydro-8-oxopyrrolo[ 1,2-a]indole 67 and tetrahydro-4-oxindole 68 (Scheme 11). These compounds in turn were readily obtained from cyclohexane-1,3-one and the appropriate amino acid salt according to Franck s pyrrole acylation protocol.53 Attempts to directly oxidize 67 or 68 to the hydroxyindole oxidation state using DDQ met with failure despite numerous attempts involving variation in solvent and reaction temperature. To circumvent this limitation, it was reasoned that... 

Metastable species derived from (L)Cu(02), where L- = 2,4-di-te/V-butyl-phenolate linked to l,4-di-z, so-propyl-l,4,7-triazacyclononane, show multiple vCuO bands in the wavenumber range 500-550 cm-1.389 The resonance Raman spectrum of [Cu2(p-0)2(flf4-Me2-etpy)2]2+ has a vCu-O-Cu band at 579 cm-1 (551 cm-1 for lsO).390 Selective catalytic reduction of NO by NH3/02 on copper-faujasite catalysts gave rise to IR bands showing changes in copper oxidation states (using the vas[Cu-0-Cu]+ band near 900 cm-1).391... 

Since the first X-ray crystal structure of a palladium(IV) complex was published by Canty [29, 30], a number of groups have undertaken the study of these relatively uncommon intermediates. In an effort to elucidate the role of palladium(IV) and palladium(II) intermediates in the reaction mechanism, Catellani prepared a number of isolable palladacycle complexes in both the (II) and (IV) oxidation states using 1,10-phenanthroline as the ligand (Scheme 8) [31]. Catellani successfully isolated palladium(IV) palladacycle 22, which was subsequently characterized by... 

Roman numerals at the top give the oxidation states used for the Pauling-type values. 

Chlorine can have different oxidation states. Using the following species, construct a redox ladder for chlorine ... 

In order for this type of material to be a potential candidate as electrode materials (batteries and electrochemical sensors or electrocatalysts), the incorporation of suitable electroactive elements, such as V or Mn, would be helpful. This would provide a certain number of centers with highCT oxidation states useful for redox processes. 

Figure 5-9 includes the formulas of the normal oxides of the representative elements in their maximum oxidation states. Use these formulas to determine the oxidation state of each element, assuming an oxidation state of 2 for oxygen. What is the oxidation state of every element in Groups lA,... 

The definition of oxidation state used herein is the charge left on the central metal after the ligands have been removed in their normal closed shell configurations. Inasmuch as this definition is based on valence-bond formalism, there are several instances of indefinite oxidation state (see Section III). It is recognized that oxidation state is not a measurable physical quantity. However, the concepts of oxidation state and d-electron configuration which are used throughout this chapter are generally useful... 

Both in the DFT and HF calculations the values of the total calculated valence of the metal atoms practically coincide with the values of the oxidation state used by chemists for these compounds. 

Unusual oxidation states of mononuclear metal complexes can be realized when the complexes are confined in the pores of zeolites or silicoaluminophosphates. The matrix mechanically prevents the thermodynamically favored and kinetically facile disproportionation to higher and lower oxidation states. Using this concept of site isolation, mononuclear [Au"(en)2] complexes (en = 1,2-ethylenediamine)... 

SIMS analysis as carried out in our previous work [12,39] provides a qualitative analysis of Cr enrichment of the surface. Based on such qualitative analysis of Cr content, a Cr203 oxide layer was proposed to develop in nanocrystalline alloy, whereas, it was proposed that a mixed Fe-Cr oxide layer forms in case of microcrystalline alloy. A Future study quantifying the Cr, Fe and O contents of oxide layer and their oxidation states using techniques such as X-ray photoelectron spectroscopy (XPS) must provide a better understanding of the effect of nanocrystalline structure on the chemical composition of oxide layer. 

The friction and the adhesion forces of ferrocene-containing polymer films was investigated as a function of the oxidation state using electrochemical atomic force microscopy [612]. 

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