Ferromagnetic oximate-bridged complexes of chromium(III)–copper(II) and of chromium(III)–copper(II)–chromium(III)

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 [salen^2–=N,N′-ethylenebis(salicylideneiminate), pdmg^2–= 3,9-dimethyl-4,8-diazaundeca-3,8-diene-2,10-dione dioximate and dmg^2–= 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.