USE OF TETRAETHYLAMMONIUM CYANIDE FOR THE PREPARATION OF CYANATED CYCLOPENTADIENYLIRON CYCLOHEXADIENYL COMPLEXES - STUDY OF THEIR ELECTROCHEMICAL AND CHEMICAL OXIDATION

Addition of tetraethylammonium cyanide to a solution of (eta(5)-cyclopentadienyl)(eta(6)-arene)iron (1+), in acetonitrile can be studied by voltammetry. With electron-withdrawing groups such as nitro, keto, sulfone, azo and azoxy bonded to the arene, the reaction occurs immediately and a wave resulting from oxidation of hexadienyl species is observed in the range 0-1V vs. SCE. Preparation of various hexadienyl compounds was achieved with good yields. In order to obtain ortho-substituted benzonitriles, electrochemical and chemical oxidations of hexadienyl complexes were compared. The best results were obtained with N-bromosuccinimide (NBS) and a demetallation generally occurs. A one-pot synthesis of benzonitrile compounds can be achieved after addition of cyanide ion and then NBS to a solution of (eta(5)-cyclopentadienyl)(eta(6)-arene) iron (1+)in acetonitrile. [CpFe(eta(6)-C6H5N(O)=NC6H4CN-2)](+) is directly obtained from the azoxy dicationic compound [(CpFe)(2)(PhN(O)NPh)](2+).