Radical Substitution in the Nickeladithiolene Ring in Bis(1-phenyl-1,2-ethenedithiolato)nickel(0)

Abstract

Substitution of the 1-cyano-1-methylethyl group for hydrogen in the nickeladithiolene ring occurs in the reaction of bis(1-phenyl-1,2-ethenedithiolato)nickel(0) with 2,2‘-azobis(isobutyronitrile). A radical mechanism is evidenced by the inhibition of the substitution in the presence of the radical scavenger TEMPO. 2,2‘-Azobis(methyl isobutyrate) and 1,1‘-azobis(1-cyanocyclohexane) undergo similar substitution reactions. The reaction is accompanied by the exchange of dithiolato ligands. Phenylation of the nickeladithiolene ring occurs in the reaction of (phenylazo)triphenylmethane. The cis−trans isomerization and the exchange of dithiolato ligands are discussed in connection with the radical substitution.