Einfluß von Ringgröße und Substitution auf die oxidative Addition cyclischer Carbonsäureanhydride und -imide an den Rumpf (N N)Niº (N N = α, α′-Dipyridyl,Tetramethylethylendiamin)

Influence of Ring Size and Substitution on the Oxidative Addition of Cyclic Carboxylic Acid Anhydrides and Imides to the Moiety (N N)Ni^º (N N = bipy, tetramethylethylenediamine) (dipy)(COD) or a mixture of tmed/Ni(COD)₂ easily react with cyclic carboxylic acid anhydrides by an oxidative addition. After decarbonylation with succinic acid anhydride a five-membered, with glutaric acid anhydride a six-membered metallacycle are formed – or With diphenic acid anhydride we obtained a seven-membered chelate in the boat form ( XIV ). Along their bond axis the two aromatic rings are twisted by 127°, i.e. the conjugative interaction is weak. Itaconic acid anhydride, as a polar olefine, can coordinate to the moiety (tmed)Ni side-on. But also on oxidative addition, yielding the five-membered chelate ( XVI ), is possible. The five-membered chelate is the only Product of the reaction with (dipy)Ni(COD). 1.8-naphthalic acid anhydride (NSA), because of its rigidity, is not suitable for an oxidative addition to electron-rich nickel(O) complexes. But as a π acceptor ligand with a relatively low half wave potential NSA displaces COD of (dipy)Ni(COD) forming (dipy)Ni(NSA) · 0.25 THF ( XVIII ). One of the final products of the acidolysis of (dipy)Ni]₂(PPI) · 1.5 THF ( XIX PPI=N-phenyl phthalimide) is benzanilide, a compound which might be an indicator of an oxidative additive connected with an -bond breaking in the course of the synthesis of XIX . But ir-data shows the framework of PPI to be preserved in the complex XIX . Evidently the bond breaking proceeds in the course of the acidolysis.