RADICAL SUBSTITUTION IN THE NICKELADITHIOLENE RING IN BIS(1-PHENYL-1,2-ETHENEDITHIOLATO)NICKEL(O)

Substitution of the 1-cyano-1-methylethyl group for hydrogen in the ni ckeladithiolene ring occurs in the reaction of bis(1-phenyl-1,2-ethene dithiolato)nickel(0) with 2,2'-azobis(isobutyronitrile). A radical mec hanism is evidenced by the inhibition of the substitution in the prese nce of the radical scavenger TEMPO. 2,2'-Azobis(methyl isobutyrate) an d 1,1'-azobis-(1-cyanocyclohexane) undergo similar substitution reacti ons. 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 excha nge of dithiolato ligands are discussed in connection with the radical substitution.