Reactions of Coordinated Nitriles and Related Ligands

Coordination of nitrile to metal directly through the nitrogen or through some other proximal atom activates the carbon toward nucleophilic attack by water and other nucleophiles. The products are commonly amides. The metal-mediated reactions of dicyanodiamide (19) have been further investigated in the presence of nickel or copper salts (19) reacts with alcohols to yield (20). 

The hydrolysis of coordinated nitriles has recently attracted some attention. A very facile hydrolysis of nitriles to the corresponding amides at platinum(IV) centers has been described.The complex [Cu(H2NCOCH2CONHNH2)Cl] is formed from the reaction NCCH2CONHNH2 the copper(II) both promotes the hydrolysis and is reduced to copper(I). The hydrolysis of 2-cyanopyridine to 2-pyridinecarboxamide is accelerated several hundred times by the copper(II) complexes of the ligands (21) and (22). In the case of the (22) some picolinic acid was formed, resulting from the intramolecular attack of alkoxide to yield an intermediate iminoester.  

Related reactions at platinum(II) centers involve the methanolysis of cis- or tra/i5-[PtCl2(PhCN)2] to yield various isomers of the iminoester complexes [PtCl2LL ] (L or L = PhCN or MeO(Ph)C=NH). The reaction of the same nitrile complex with lithium phenylamidate yields the triazadiketonate analog (23). 

A number of catalytic reactions of isocyanates in the presence of ruthenium clusters has been reported. In the presence of [HRu3(CO)n] , EtaSiH reacts with RNCO to yield the novel spiro compound (24), while hydrogenation in the presence of [H3Ru4(CO)i2] yields RHNCONRCHO mechanisms were proposed for 

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