Dinuclear Co III /Pr III and Co III /Nd III Complexes Derived from a Hexadentate Schiff Base: Synthesis,Structure and Magnetic Properties

Abstract

Two heterodimetallic complexes of formulae [LCo(AcO)₂Pr(NO₃)₂] and [LCo(AcO)₂Nd(NO₃)₂] (H₂L=N,N'-bis(3-methoxysalicylidene) propane-1,2-diamine) have been synthesised and structurally characterised. The cobalt(III) ion shows a slightly distorted octahedral geometry in which the equatorial plane is formed by the N₂O₂ set of the Salen-type Schiff base, and the axial positions are occupied by two oxygen atoms from both acetate groups. The praseodymium(III) and neodymium (III) ions are decacoordinated. In addition to the four oxygen atoms of the Schiff base, the rare earth ions coordinate two bidentate nitrate groups and two oxygen atoms of the acetate groups. The metal ions are bridged by both the phenolate oxygens and the acetate groups. The χ_MT values observed for the complexes are lower than the free-ion approximation of Pr^III and Nd^III ions, although the cobalt(III) is diamagnetic.