Cyanoalkyl complexes of platinum(II) : III. Alcoholysis and hydrolysis of the CN group

Abstract

Nucleophilic additions of alcohols, thiols and water to the σ-coordinated CN group of cis-[Pt( o-CH 2C 6H 4CN)(PPh 3) 2] 2(BF 4) 2 give quantitative yields of stable N-bonded iminoether, iminothioether and amide complexes. The proposed mechanism involves a fast replacement of the σ-coordinated CN by the nucleophile HY followed by the intramolecular attack of HY on the ligand in the cis position. π-Coordination of CN to Pt II has not been observed. The addition of methanol to other cyanoalkyls did not lead to stable iminoether complexes. The amide complex cis-[Pt(CH 2C 6H 4CONH 2)(PPh 3) 2] 2(BF 4) 2 is converted into the nonionic imide cis-[Pt(CH 2C 6H 4CONH)(PPh 3) 2] 2 in methanolic KOH but it catalyzes for a few cycles the conversion of benzonitrile to benzamide by water under neutral conditions. The imino and isonitrile have a higher trans effect than alkyl groups whereas their trans influence as indicated by 1 J(PtP) coupling constants is smaller.