Ferromagnetic oximate-bridged complexes of chromium(<scp>III</scp>)–copper(<scp>II</scp>) and of chromium(<scp>III</scp>)–copper(<scp>II</scp>)–chromium(<scp>III</scp>)

Abstract

An oximate-bridged binuclear chromium(III)–copper(II) complex [(salen)Cr(pdmg)Cu]ClO41 and a trinuclear chromium(III)–copper(II)–chromium(III) complex [{(salen)Cr}2(dmg)2Cu]2 have been prepared and characterized [salen2–=N,N′-ethylenebis(salicylideneiminate), pdmg2–= 3,9-dimethyl-4,8-diazaundeca-3,8-diene-2,10-dione dioximate and dmg2–= dimethylglyoximate]. Magnetic susceptibility measurements in the temperature range 4.2–300 K demonstrated the operation of a ferromagnetic interaction between the adjacent chromium(III) and copper(II) ions through oximate bridges in both 1 and 2. Based on spin Hamiltonians ℋ=–2JŜ1·Ŝ2(S1=, S2=½) and ℋ=–2J(Ŝ1·Ŝ2+Ŝ2·Ŝ3)(S1=S3=, S2=½), the exchange integrals (J) were evaluated as +12.6 and +13.0 cm–1 for 1 and 2, respectively.