Cyanide linkage isomerism

This last reaction, which involves a cyanide linkage isomerization, was inferred from the observation of a first order decay for an intermediate. The half life of this intermediate is 1.6 sec at 25°. A similar reaction, the oxidation of Cr+2 by Com(NH3)5(CN)+2, was investigated by Espenson and Birk (1965). Two steps were observed in the kinetics. The first obeys a second order rate law,... 

An extrapolated spectrum for the presumed fsocyanide intermediate yields a maximum at 5450—5600 A which is in reasonable agreement with the expected value for five waters and a nitrogen bonded cyanide. Alternate interpretations of the first order step are a CN flip in a CN bridged intermediate or the break-up of a bridged intermediate. Espenson and Birk consider this less likely than the simple terminal cyanide linkage isomerization. 

B. Complexes Exhibiting Cyanide Linkage Isomerism / 253 IV. MAGNETIC PROPERTIES... 

A clear case of cyanide linkage isomerism was established for the pentanuclear TBP complex [Fe tmphen)2]3[Cr (CN)g]2 (174a). Unlike the similar complexes [Fe°(tmphen)2l3 [M ° CN)g]2 (M = Co or Fe), which exhibit temperature induced transitions between the high- and low-spin state at the equatorial Fe(II)... 

Linkage isomerism is but a special case of ambidentate behavior in ligands. The cyanide ion provides good examples of such behavior. In discrete complexes it almost always bonds through the carbon atom because of the. stronger tt bonding in that mode. It has also been reported to form a few linkage isomers such as cjj-[Co(lrien)(CNK] and c/4 4Co(trien)(NC)j]. ... 

Nitrogen Carbon Linkage.—From their relationship to primary amines both by decomposition and by synthesis the constitution of the isocyanides is proven to be R—NC. Taking methyl cyanide and methyl iso-cyanide for illustration the formulas of these isomeric compounds are... 

Corey et al.a were interested in developing a simple procedure for oxidation of allylic alcohols to carboxylic acids without cis-irans isomerization of the ,/3-unsaturated linkage. They reasoned that in the presence of hydrogen cyanide and cyanide ion the a,/3-unsaturated aldehyde would be converted into the cyanohydrin which would be oxidized by Mn02 to an acyl cyanide, which in the presence of an alcohol would be converted into an ester ... 

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