Synthesis, Crystal Structures, and Magnetic Properties of Two New 1D Copper(II) Coordination Polymers Containing Fumarate(−2) and Chelating N,N′-Donor as Ligands

Abstract

Two new polynuclear complexes of CuII, [Cu2(fum)(μ-OH)(bpy)2(H2O)](NO3)·2H2O (1) (fum = fumarate dianion, bpy = 2,2′-bipyridine) and [Cu(fum)(tmen)]·2H2O (2) (tmen = N,N,N′,N′-tetramethylethane-1,2-diamine), have been synthesized and structurally characterized by X-ray crystallography. Complex 1, C24H27Cu2N5O12, crystallizes in a triclinic system, space group Pequation image , with a = 10.168(14), b = 11.347(14), c = 14.74(2) Å, and Z = 2; complex 2, C10H22CuN2O6, crystallizes in an orthorhombic system, space group Pbca, with a = 14.701(19), b = 14.899(19), c = 26.90(3) Å, and Z = 16. Compound 1 is an alternating chain compound, with alternate repetition of bis(monodentate) (μ2) and bis(bidentate) (μ4) bridging modes of fumarate, showing ferromagnetic interaction between CuII ions through hydroxo bridges with a Cu−O−Cu angle of 108.5°. Compound 2 is a linear 1D zig-zag polymer. There are two copper(II) ions with equivalent coordination and geometry in the asymmetric unit, each of them bonded to a bidentate tmen ligand and to two different fumarate moieties. Magnetic susceptibility data were measured in the 300−2 K temperature range. The magnetic data for 1 were fitted by use of a ferromagnetic/antiferromagnetic alternating S = 1/2 chain system and show the following results: JF = +5.4 cm−1, JAF = −0.25 cm−1, g = 1.96. The susceptibility data of 2 were fitted by use of the Bonner−Fisher expression for antiferromagnetically coupled S = 1/2 local spins, giving the parameters J = −1.81 cm−1, g = 2.03.