REAKTIONEN VON NICKEL(0)-KOMPLEXEN MIT p-CHINONEN. BILDUNG PHOSPHINSUBSTITUIERTER RADIKALANIONEN

Article abstract of DOI:10.1016/S0022-328X(00)95264-1

(dipy)Ni(COD) react with duroquinone (Dch) or anthraquinone (Ach) to yield the complexes (dipy)Ni(η⁴-Dch) or (dipy)Ni(η⁴-Ach).Chloranil (CA), however, reacts as an oxidant and depending on the temperature (dipy)Ni^II(CA^2-) or following an oxidative addition (diply)Ni^II(Cl)(CAH^-)(THF) are formed.By substitution of (Cy3P)2Ni(C2H4) the complexes (Cy3P)Ni(η⁴-Dch) or (Cy3P)2Ni(η⁴-Ach) are obtained, whereas a 1,1-coupling of quinone and the coordinated phosphine proceeds during the reaction between p-benzoquinone of chloranil and (Cy3P)2Ni(C2H4).By ESR studies it was demonstrated that with Ni(Cy3P...Ch)2 or Ni(Cy3P...CA)2, resp., complexes are obtained, in which radical anions, which are derived from the product of this 1,1-coupling, are coordinated to low-spin nickel (II).There is a significant difference between (Cy3P)2Ni(C2H4) and the analogous platinum or palladium complexes, which are substituted by p-benzoquinone while an oxidative addition proceeds with chloranil.