NICKEL(II) COMPLEXES OF SOME 3-SUBSTITUTED-2,4-PENTANEDIONES AND THEIR ADDUCTS WITH 2,2'-BIPYRIDINE AND 1,10-PHENANTHROLINE

Nickel(II) complexes of 3-substituted-2,4-pentanediones (R-acacH,R = C l, Ph, NO2) and their adducts with 2,2'-bipyridine (bipy) and 1,10-phe nanthroline (phen) have been synthesised and characterised by microana lyses, conductance, magnetic and spectral measurements. Four different nickel(II) complexes of 3-phenyl-2,4-pentanedione have been isolated. The conductance data show that they are non-electrolytes except for t he [Ni(phen)3](Ph-acac)2, [Ni(phen)3] (Cl-acac)2 and [Ni(phen)3] (NO2- acac)2 adducts which are 1:2 electrolytes in nitromethane. The ligand field spectral bands of [Ni(NO2-acac)2].2H2O suggest that this compoun d is a mixture of octahedral and tetrahedral species in solution. The infrared spectral shifts in the adducts suggest the formation of Ni-N bonds while the presence of carbonyls in different environments was ob served in [Ni(NO2-acac)2.phen2], [Ni(phen)3] (Cl-acac)2, [Ni(phen)3] ( Ph-acac)2 and [Ni(phen)3] (NO2-acac)2. Octahedral coordination about t he nickel(II) ion and two outer-sphere anions in the 1:3 adducts have been proposed for the compounds except the red [Ni(Ph-acac)2] complex which is a mixture of octahedral and square-planar species.