Synthesis, structure, and magnetic properties of discrete d–f heterodinuclear complexes designed from tetrahedrally distorted [Cu(salabza)] (H2salabza = N,N′-bis(salicylidene)-2-aminobenzylamine) and [Ln(hfac)3] (Hhfac = 1,1,1,5,5,5-hexafluoroacetylacetone, Ln = Gd or Lu)

Abstract

A tetrahedrally distorted mononuclear copper(II) complex, [Cu(salabza)] 1, and two dinuclear CuLn complexes, [Cu(salabza)Ln(hfac)₃] (Ln = Gd 2 or Lu 3), were synthesized and their molecular structures determined, where H₂salabza and Hhfac denote N,N′-bis(salicylidene)-2-aminobenzylamine and 1,1,1,5,5,5-hexafluoroacetylacetone, respectively. In complex 1 the deviations of the four co-ordinating atoms (O(1), O(2), N(1) and N(2)) of salabza²⁻ and the copper atom from the least-squares equatorial plane O(1)O(2)N(1)N(2) indicate the tetrahedral distortion around Cu. In 2 and 3 the Cu^II and Ln^III are bridged by the two phenolic oxygens of salabza²⁻. The Cu⋯Ln distances are 3.2481(8) Å for 2 and 3.1825(7) Å for 3. The structures of 2 and 3 were found to consist of a perfectly discrete dinuclear CuLn unit, the shortest intermolecular Cu⋯Cu, Cu⋯Ln and Ln⋯Ln distances being 6.002(1), 7.522(1) and 8.507(1) Å for 2, and 5.998(1), 7.509(1) and 8.584(1) Å for 3, respectively. Cryomagnetic susceptibility measurements of 2 in the region of 2 K to room temperature indicated the operation of a ferromagnetic interaction between Cu^II and Gd^III, with J = +0.8 cm⁻¹ based on H = −2JS_Cu·S_Gd. This was confirmed by measurements of the field dependence of magnetization at 2 K.