Magnetische Untersuchungen an Komplexen von La(III), Pr(III) und Nd(III) mitSchiffschen Basen

Abstract

Specific magnetic susceptibilities (χ_s) of several newly synthesized chelates of some of the lanthanons [La(III), Pr(III) and Nd(III)] are reported. These derivatives are of the general type,Ln(O-i-C₃H₇)_3−n (C₆H₅CH∶NRO) _n [where,Ln=La(III), Pr(III) or Nd(III);n=1 or 2 and R=CH₂CH₂, CH₂CHCH₃ or C₆H₄] and have been prepared by the reaction of the alkoxides of the lanthanons withSchiff bases such as benzylidene-2-hydroxyethylamine (C₆H₅CH∶NCH₂CH₂OH), benzylidene-2-hydroxy-n-propylamine (C₆H₅CH∶NCH₂CHOHCH₃) and benzylidene-o-aminophenol (C₆H₅CH∶NC₆H₄OH) in different molar relations in dry benzene.

The resulting crystalline derivatives are non-volatile, light to deep yellow or blackish in colour. These tend to polymerize on keeping as shown by their insoluble nature and higher melting points, the polymerisation possibly occurring by the intermolecular coordination through oxygen atoms as reported earlier¹.

UsingGouy method², the bis-isopropoxy mono-Schiff base and mono-isopropoxy bis-Schiff base complexes of La(III) have been shown to be diamagnetic, with χ_s values being in the range of −0.32 to −0.45×10⁻⁶ and −0.39 to −0.55×10⁻⁶ c.g.s. units at 305 K respectively.

In the remaining derivatives, Pr(O-i-C₃H₇)_3−n (C₆H₅CH∶ NRO) _n and Nd(O-i-C₃H₇)_3−n (C₆H₅CH∶NRO) _n (where,n=1 or 2 and R=CH₂CH₂, CH₂CHCH₃ or C₆H₄) the magnetic moment values range between 3.25 to 3.32 and 3.30 to 3.33 μ_B respectively indicating their paramagnetic nature.