Bis(diazadien)metall(O)-Komplexe, IV. Nickel(O)-bis(chelate) mit aromatischen N-Substituenten/ Bis(diazadiene)metal(O) Complexes, IV. Nickel(O)-bis(chelates) with Aromatic N-Substituents

With N-aromatic substituted diazadienes (DAD) and R 3 = R 4 = aryl) nickel(O) forms complexes of composition (DAD) 2 Ni which are prepared preferably by reduction of Ni(II) salts in the presence of DAD. The groups R 1 , R 2 and/or the o-substituents of the aryl system determine the conformation of the DAD and its sterical ligand properties. An X-ray structure analysis of (DAD) 2 Ni 17 (DAD = glyoxalbis( 2,6-dimethyl-phenylimine)) shows a dihedral angle of 44° between the two chelate planes. With twisted N-aryl substituents nickel seems to prefer planar coordination (formal low spin Ni(II)) of two DADs over tetrahedrally coordinated formal nickel(O) state.