Nickel scorpionate complexes containing poly(aryl ether) dendritic substituents

Abstract

Novel dinitratonickel(ii) complexes with bis(pyrazolyl)methane ligands at the focal point of poly(aryl ether) Fréchet dendrons of up to the third generation are reported. The complexes are accessible by direct reaction of the corresponding scorpionate ligand with Ni(NO3)2, or by treatment of the dibromidonickel derivatives with AgNO3, although they reversibly convert to the dibromidos in the presence of KBr. The paramagnetic compounds could be characterized by 1H NMR in solution. The molecular structure of metallodendrimers G0 and G1 [Ni(NO3)2{(Gn-dend)CH(3,5-Me2pz)2}] have been determined by X-ray diffraction methods. Both structures show an almost identical three-dimensional organization of the –ArCH2CH(3,5-Me2pz)2Ni(NO3)2 moieties, with the nickel atoms exhibiting a distorted octahedral structure with a scorpionate-κ2 and two bidentate nitrato ligands.