Oxidation number assistance with

The usefulness of determining the oxidation number in chemistry is twofold. First, it helps determine if there is a change in the oxidation number of a given element in a reaction. This always signals the occurrence of an oxidation-reduction reaction. Thus, it helps tell us whether a reaction is a redox reaction or some other reaction. Second, determining the oxidation number assists with detemining the number of electrons involved, which aids in balancing the equation. 

Minetto et al. (2004) carried out synthesis of tetrasubstituted pyrroles (and trisub-stituted furans) in a three-step reaction of P-ketoester with an aldehyde followed by oxidation to give number of substituted 1,4-dicarbonyl compounds, which is further cyclized by microwave-assisted with the Paal-Knorr reaction. 

Over the past few years, a large number of experimental approaches have been successfully used as routes to synthesize nanorods or nanowires based on titania, such as combining sol-gel processing with electrophoretic deposition,152 spin-on process,153 sol-gel template method,154-157 metalorganic chemical vapor deposition,158-159 anodic oxidative hydrolysis,160 sonochemical synthesis,161 inverse microemulsion method,162 molten salt-assisted and pyrolysis routes163 and hydrothermal synthesis.163-171 We will discuss more in detail the latter preparation, because the advantage of this technique is that nanorods can be obtained in relatively large amounts. 

A number of other routes are available for the syntheses of diquaternary salts of 4,4 -bipyridines. One method that has been extensively studied involves reaction of a 1-alkylpyridinium salt with sodium amalgam (or sodium in liquid ammonia) to form the 1,1 -dialkyl-1,1, 4,4 -tetrahydro-bipyridine, which is readily oxidized to the corresponding l,l -dialkyl diquaternary salt. This reaction is analogous to the synthesis of 4,4 -bipyridine by the action of sodium on pyridine, followed by oxidation of the intermediate tetrahydrobipyridine. " The reduction may be achieved electrolytically or by reaction with zinc or magnesium. Various oxidizing agents have been used to assist the conversion to the di-quaternary Another synthesis of diquaternary salts of... 

In samples of yttrium oxide codoped with europium and other trivalent rare-earth ions they correlated the 5D0->7F2 europium-emission intensities with the number of near resonances with a second ion. The permissable mismatch from a perfect resonance match was allowed to be 500 cm-1. The magnitude of the mismatch was chosen in such a way as to prohibit the inclusion of any phonon-assisted transfers. 

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