Structural and magnetic characterization of copper(II) halide complexes with 2-(dimethylaminomethyl)-3-hydroxypyridine

Abstract

Dimeric complexes, bis[dihalo(2-dimethylaminomethyl-3-hydroxypyridine)-copper(II)], [Cu(dmamhp)X 2] 2, were prepared from the reaction of copper(II) halide (Cl, Br) with 2-dimethylaminomethyl-3-hydroxypyridine (dmamhp) in methanol, and their single crystal structures were determined. The chloro compound was crystallized as green needles in space group P 1 ¯ of the triclinic system with Z = 1 and unit cell dimensions a = 7.3420(12), b = 9.196(3), c = 9.817(2) Å, α = 115.16(3)°, β = 92.433(16)° and γ = 111.59(2)°. The corresponding values for the bromo complex are a = 7.5652(15), b = 9.191(3), c = 9.7926(13) Å, α = 113.912(14)°, β = 92.396(14)° and γ = 111.24(2)°. The chloro compound consists of a dimeric molecule [Cu(dmamhp)Cl 2] 2, in which copper(II) ions are bridged by chloride ligands. The geometry at the copper is distorted trigonal bipyramidal with the pyridine nitrogen [N9], terminal chloride [Cl1] and the bridging chloride [Cl2 i] in the equatorial site; and with the amine nitrogen [N9] and the remaining bridging chloride [Cl2] in the axial site. The dimer units are held through the hydrogen bonding between the hydroxy group in a pyridine ring and the terminal chloride ion. The bromo compound shows a similar structure. The magnetic susceptibility data of both compounds were followed by the Bleaney–Bowers dimer equation with J = −11.17 and −21.11 cm −1 for the chloro and bromo complexes respectively, indicating that there are antiferromagnetic interactions between the copper(II) ions in the solid state.