Novel dioximato-bridged chromium(III)-copper(II)-chromium(III) trinuclear complexes with ferromagnetic exchange interactions

Abstract

Two new dioximato-bridged trinuclear CrII-CuII-CrIII complexes, [Cr(salen)-Cu(α-BD)2-Cr(salen)] (1) and [Cr(salen)-Cu(α-FD)2-Cr(salen)]-H2O (2), have been prepared and characterized [salen2− = N,N′-ethylene-bis (salicylideneiminate), (α-BD)2− = α-benzyldioximato and (α-FD)2− = α-furildioximato]. Magnetic susceptibility measurements in the 4.2–300 K range demonstrated the operation of a ferromagnetic interaction between the adjacent CrIII and CuII ions through oximato bridges in both (1) and (2). Based on spin Hamiltonians Ĥ=−2J(Ŝ1Ŝ2+Ŝ2Ŝ3)(S1=S3=3/2,S2=1/2) the exchange integrals (J) were evaluated as 3.19 and 5.38 cm−1 for (1) and (2), respectively.