Silver complexes cyanopyridines

In general, the relationship between the Kb values for the bases (measured toward the proton) is approximately linearly related to the K values for the formation of the silver complexes when several nitrogen bases (amines) having similar structure are considered. However, for a base such as 4-cyanopyridine, it is found that the silver complex is much more stable than would be predicted from the basicity of the ligand toward H+. The reason for this is that some multiple bonding in the silver complex is possible as shown here ... 

Table 15 Some IR Spectral Data (cm ) for Silver(I) Complexes of Cyanopyridines...

Following the well-known Pinner synthesis of imidates by the reaction of nitriles with alcohols, there has been considerable interest in recent years in treating a nitrile bond within the coordination sphere of metal ions with water or alcohols. It has been suggested that the initial step consists of nucleophilic attack of an external or coordinated hydroxide or alkoxide anion on the nitrile carbon atom. A number of imidate complexes have been isolated from the reactions of 2-cyanopyridine with metal [Cu", Ni , Co" and Fe"] salts in alcohols, of frans-PtMeClL with pentafluorobenzonitrile and silver hexafluorophosphate in alcohols," and of o-cyanobenzylplati-num complexes. "... 

ZhaoX-L, Mak TCW (2004) Silver cages with encapsulated acetylenediide as building blocks for hydrothermtil synthesis of supramolecular complexes with n-cyanopyridine and pyridine-n-carboxamide (n = 3,4). Dalton Trans 3212-3217... 

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