Reactions with metal oxalates

These solvents dissolve the chalcogen elements sulfur, selenium, and tellurium, and therefore can be used for the solvothermal synthesis of metal chalcogenides by the reaction of metal oxalate with chalcogens at 120°C-200°C. It has been reported that the reaction also proceeds in tetrahydrofuran or pyridine, but the reaction in polyamines having more than two chelating atoms proceeds more completely. ... 

Phenobarbital is prepared by treating benzyl ehloride with sodium eyanide when benzyl eyanide (or a-phenyl acetonitrile) is formed with the elimination of a moleeule of sodium chloride. Benzyl cyanide, first on hydrolysis yields phenyl aeetic acid which on subsequent esterification with ethanol forms the eorresponding ester as ethyl phenyl acetate. This on reaction with diethyl oxalate in the persence of absolute ethanol and sodium metal gives diethyl phenyl oxalo acetate which on distillation at 180°C results into phenyl malonic ester. When it is treated with ethyl bromide and sodium ethoxide, the lonely active hydrogen atom gets replaced with an ethyl group thus forming ethyl phenyl malonic ester. Lastly, this on condensation with urea loses two molecules of ethanol and finally forms the desired compound phenobarbital. 

Recently, it was found that not only oxides, but also transition metal oxysalts, such as carbonates and oxalates, can be electrochemically active and a conversion reaction takes place where Li reacts reversibly with the complex anion. As compared to other displacement reactions with metal oxides and fluorides, the use of a low molecular weight salt does not penalize the capacity, while giving extra stability due to the formation of lithium carbonate as the main side product. The electrochemical reactions of MnCOs and FeC204 can be written as... 

Reaction of Metal Oxalate Hydrates with Hydrazine Hydrate... 

Oxalamidinate anions represent the most simple type of bis(amidinate) ligands in which two amidinate units are directly connected via a central C-C bond. Oxalamidinate complexes of d-transition metals have recently received increasing attention for their efficient catalytic activity in olefin polymerization reactions. Almost all the oxalamidinate ligands have been synthesized by deprotonation of the corresponding oxalic amidines [pathway (a) in Scheme 190]. More recently, it was found that carbodiimides, RN = C=NR, can be reductively coupled with metallic lithium into the oxalamidinate dianions [(RN)2C-C(NR)2] [route (c)J which are clearly useful for the preparation of dinuclear oxalamidinate complexes. The lithium complex obtained this way from N,N -di(p-tolyl)carbodiimide was crystallized from pyridine/pentane and... 

Despite the volume of work concerned with metal-catalyzed decomposition of diazo compounds and carbenoid reactions 28>, relatively little work has been reported on the metal-catalyzed decomposition of sulphonyl azides. Some metal-aryl nitrene complexes have recently been isolated 29 31>. Nitro compounds have also been reduced to nitrene metal complexes with transition metal oxalates 32K... 

The scope of CAR-CLS in analytical determinations has been expanded with one other type of CL reaction (luminol-based CL reactions are restricted to direct determinations of metal ions and some indirect ones). The so-called energy transfer CL is one interesting alternative, with a high analytical potential. As stated above, PO-CL systems based on the reaction between an oxalate ester and hydrogen peroxide in the presence of a suitable fluorophore (whether native or derivatized) and an alkaline catalyst are prominent examples of energy transfer CL. This technique has proved a powerful tool for the sensitive (and occasionally selective) determination of fluorophores its implementation via the CAR technique is discussed in detail later. 

Ammonium carbonate slowly decomposes on exposure to air, or rapidly breaks down on heating to ammonia, CO2, and water bberates CO2 on treatment with dilute mineral acids. It reacts with metals forming their carbonates. Reaction with hydriodic acid produces ammonium iodide and forms ammonium oxalate with oxabc acid. 

Barium acetate converts to barium carbonate when heated in air at elevated temperatures. Reaction with sulfuric acid gives harium sulfate with hydrochloric acid and nitric acid, the chloride and nitrate salts are obtained after evaporation of the solutions. It undergoes double decomposition reactions with salts of several metals. For example, it forms ferrous acetate when treated with ferrous sulfate solution and mercurous acetate when mixed with mercurous nitrate solution acidified with nitric acid. It reacts with oxahc acid forming barium oxalate. 

In an atmosphere of nitric oxide, thermal decomposition produces barium nitrite, Ba(N02)2. Reactions with soluble metal sulfates or sulfuric acid yield barium sulfate. Many insoluble barium salts, such as the carbonate, oxalate and phosphate of the metal, are precipitated by similar double decomposition reactions. Ba(N03)2 is an oxidizer and reacts vigorously with common reducing agents. The solid powder, when mixed with many other metals such as aluminum or zinc in their finely divided form, or combined with alloys such as... 

Photooxidation of coordinated oxalate has been known since the earliest studies of transition metal photochemistry (42). In these reactions oxalate ligand is photooxidized to CO2, and up to two metal centers are reduced by one electron (e.g. ferrioxalate). We wondered whether the oxalate ligand could be a two-electron photoreductant, by simultaneous or rapid sequential electron transfer, with metals prone to 2e redox processes. Application of this concept to l6e square planar d complexes, Equation 15, was attractive because it should produce solvated I4e metal complexes that are inorganic analogues of... 

After providing a brief description of zeolitic structures, we discuss the hierarchy of structures of open-framework metal phosphates ranging from zerodimensional monomeric units and one-dimensional linear chains to complex three-dimensional structures. Aspects related to the likely pathways involved in the assemblage of these fascinating structures are examined, pointing out how the formation of the complex three-dimensional structures of open-framework metal phosphates involves the transformation and assembly of smaller units. Besides the role of the four-membered monomer, the amine phosphate route to the formation of the three-dimensional structures is discussed. The last step in the formation of these structures from preformed units of the desired structure is likely to be spontaneous. Our recent studies of open-framework metal oxalates have shown the presence of a hierarchy of structures. Reactions of amine oxalates with metal ions yield members of the oxalate family with differing complexity. 

The survey of the investigations and results covers the release of water from salts and hydroxides, the calcination of carbonates and oxalates, the reactions of metallic oxides and carbonates with SO2, and reactions on the surface of carbon. The application of the non-isothermal method to the thermal decomposition of carboxylic acids and polymeric plastics as well as to the pyrolyses of natural substances, in particular bituminous coal, is explained. Finally, chemical reactions in a liquid phase, the desorption of gases from solids, annihilation processes in disturbed crystal lattices and the emission of exo-electrons from metallic surfaces are discussed. 

Condensed imidazoles are formed in excellent yield when aromatic nitro compounds, substituted in the ortho position with an N-heteroparaffinic substituent, are cyclized using various reducing agents such as metal oxalates, iron pentacarbonyl, triethylphos-phite,113 or titanous chloride.114 The same reaction takes place under... 

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