Pyridine 1-oxide metalation

Pyridine 1-oxide, like pyridine, can act as a ligand in transition metal complexes, but unfortunately good stability constants are not known. However, Shupack and Orchin have found that the C===C stretching frequency of the ethylene ligand in trans-ethylene pyridine 1-oxide dichloroplatinum(II) varies linearly with the pA and hence with the C7-value (ct+ or a, respectively) of substituents in the pyridine oxide. The data for the above reaction series are included in Table V. 

In the production of 4,4 -bipyridyl from pyridine, the reaction between pyridine and metallic. sodium in liquid ammonia is involved, followed by oxidation. By adopting a continuous reactor, the process has been made safer and yields have probably improved. For a hazardous chemical like diazomethane, even at a capacity of 60 tpa a continous plant has been adopted. 

Experimentally it has been found that primary and secondary amines react by solvolysis, while only the tertiary amines generally produce reduction, if reduction is observed. It thus seemed appropriate to study the reaction of niobium (V) halides with pyridine, where proton dissociation need not be considered and any reaction would necessarily lead to a simple adduct of pyridine or reduction of the metal halide. In this work, reduction of the niobium(V) halides was observed, and the reaction products were characterized. Elucidation of the pyridine oxidation products has permitted an interpretation of the reaction mechanism in terms of the two-electron reduction of niobium(V) by the pyridine molecule. 

The reaction depicted also proceeds between pyridine oxide in its neutral form and the double amount of benzophenone metal-ketyl. Pyridine bases (not N-oxides) do not react with the ketyls. The N-oxides of pyridine and y-picoline give both the N-oxide of the pyridyl carbinol and the pyridyl carbinol without the N-oxide oxygen. Yields can be 70 and 80%, respectively (depending on the metal nature in the metal-ketyl). Having pronounced physiological activity, these compounds are the key materials in syntheses of atropine-like drugs. 

In metal-containing systems, synthons involving coordinated water or am-mine ligands are possible. For example, hydrogen bonding between coordinated water and pyridine oxide ligands in a R2(8) motif has been observed to link cobalt 4,4 -bipyridine dioxide coordination polymers into sheets [60]. 

Incompatible with ethanol, ethanol + butadiene, ethanol + phosphorus, ethanol + methanol + HgO, formamide + pyridine + sulfur trioxide, formamide, halogens or interhalogens (e.g., chlorine), mercuric oxide, metals (e.g., aluminum, lithium, magnesium), metal carbides (e.g., lithium carbide, zirconium carbide), oxygen, pyridine, sodium hydride, sulfides. 

Kiplinger and co-workers have also demonstrated dearomatization of pyridines with metals <05CC2591>. In the case reported, thorium complexes mediated ring opening and dearomatization of pyridine Al-oxides yielding the thorium oximate complexes. 

MAA (108-31-6) Combustible solid (flash point 215°F/102°C). Dust cloud forms an explosive mixture with air. Dissolves in water, forming maleic acid with release of energy. Violent reaction with strong oxidizers, strong alkalis. Contact with amines or alkali metals lithium, sodium, potassium, rubidium, cesium, and francium (even in low concentrations of 200 ppm) can decompose rapidly and may cause polymerization, especially if temperature is >150°F/66°C. Incompatible with pyridine. Attacks metals in the presence of moisture. Attacks some plastics, rubber, and coatings. In firefighting, water stream or foam may cause frothing. 

A typical rechargeable battery based on this idea has been constructed. It uses the [Ni(TTL)]a, polymer as the anode, poly-2-vinyl-pyridine-iodine (P2VP (x/2)l2) (68) complex as the cathode, and aqueous KI solution as the electrolyte solution (Equation 13). In the discharging process, electrons flow from the anode [Ni(TTL)]a to the cathode P2VP (x/2)l2 through the load circuit the iodide (or polyiodide) ions formed at the cathode then enter the electrolyte while an equivalent amount of iodide ions from the electrolyte solution intercalate into the oxidized metal tetrathiolene polymer (anode). The electrolyte concentration is therefore conserved. Upon recharging with an opposite... 

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