Synthesis and magnetic properties of chromium(III)-nickel(II)-chromium(III)_trinuclear complexes with extended dioximato groups

Abstract

Three new trinuclear chronium(III)-nickel(II)-chromium(III) complexes with extended dioximato-bridges were prepared, and characterized, namely [Cr(salen)-Ni(dmg) 2-Cr(salen)] ( 1), [Cr(salen)-Ni(α-BD) 2-Cr(salen)] · H 2O ( 2) and [Cr(salen)-Ni(α-FD) 2-Cr(salen)] · 2H 2O ( 3), (dmg 2− = dimethylglyoximato); ( α-BD) 2− = α-benzyldioximato; ( α-FD) 2− = ( α-furildioximato); and salen 2− = N,N′-ethylenebis(salicylideneiminate). Based on elemental analysis, conductivity measurements and IR spectra, the complexes are proposed to have an extended dioximato-bridged structure. The magnetic susceptibilities of complexes ( 1) and ( 2) were measured over an 80–300 K range, giving the exchange integral J = −4.76 cm −1 for ( 1) and J = −3.38 cm −1 for ( 2), respectively. These results revealed the operation of an antiferromagnetic spin-exchange interaction between the terminal chromium(III) ions.