Synthèse électrochimique de complexes Ni(O)‐diazabutadiène

Electrochemical Synthesis of the Ni(O)‐Diazabutadiene Complexes The electrochemical reduction of Ni salts in the presence of diazabutadiene ligands (DAB = RNCHCHNR, R = t ‐Bu, o ‐xylyl, p ‐anisoyl, p ‐tolyl) has been studied in DMF by cyclic voltammetry and rotating disc polarography. In solutions containing DAB and halide X − , Ni(II) can be reduced to Ni(DAB) 2 , and the features of this reduction agree with a mechanism where the second DAB replaces X − in the coordination sphere of Ni only after its reduction to Ni(O). Rather concentrated (≃ 0.1M) solutions of NiBr 2 · DME and DAB in DMF have been electrolyzed without a supporting electrolyte, making the isolation of the product Ni(DAB) 2 particularly easy. Thus, gram quantities of Ni(DAB) 2 can be conveniently prepared within a few hours.