Synthesis, crystal structures and magnetic properties of a 1D chain based on trinuclear Cu subunits and a Cu4Dy2 complex

Two unprecedented compounds, namely a one-dimensional (1D) chain based on Cu3 subunits and a Cu4Dy2 complex have been obtained. In 1, the magnetic couplings of J1 and J2 are antiferromagnetic and ferromagnetic, respectively, in which the value of J1 was firstly determined in polynuclear Cu complexes containing Mtta ligand. [Display omitted] •A one-dimensional (1D) chain based on Cu3 subunits and a Cu4Dy2 complex have been obtained, and the topologies of both compounds have not been reported previously.•5-methyl tetrazolate (Mtta) in 1D chain was synthesized by through in situ reaction of acetonitrile and azides.•The magnetic coupling between CuII ions through the paths of CuNNCu and Cu-Oalkoxido-Cu is antiferromagnetic, whose value was firstly determined in polynuclear Cu complexes containing Mtta ligand. A one-dimensional (1D) chain [Cu3(HL)2(N3)(Mtta)]n.0.5CH3CN (1, H3L = 2-((2-hydroxybenzylidene)amino)propane-1,3-diol and Mtta = 5-methyl tetrazolate) and a Cu4Dy2 complex [Cu4Dy2{(py)2CO2}2{(py)2C(OH)O}2(CH3COO)4(N3)4].3CH3CN (2, (py)2C(OH)2 = the gem-diol form of di-2-pyridyl ketone) were obtained by the assemblies of the H3L ligand and Dy(NO3)3·5H2O with copper nitrate or with copper acetate and di-2-pyridyl ketone under the MeCN solution containing triethylamine or containing NaOH. In 1, three CuII ions were linked into a trinuclear Cu unit by three neighboring N atoms of Mtta ligand and two alkoxido-type O atoms from two HL2− ligands, then these units were further linked into a one-dimensional (1D) chain by two phenoxido O atoms from two HL2− ligands. In 2, two CuII and two DyIII ions formed a butterfly-type topology, which was further linked another two CuII by the O atoms from (py)2CO22– or from acetate ligands. Magnetic studies indicated that, in 1, the magnetic coupling through the paths of CuNNCu and Cu-Oalkoxido-Cu is antiferromagnetic (J1 = −14.81 cm−1), and its value was first determined in the polynuclear Cu complexes containing Mtta ligand. However, the magnetic coupling through the path of Cu-Ophenoxido-Cu is ferromagnetic (J2 = 24.61 cm−1). Magnetic studies revealed that 1 exhibits slow magnetic relaxation behavior, with an energy barrier Ueff of 6.06 K. The orientations of the easy magnetization axes of DyIII ions in 2 was estimated by Magellan program, indicating that the easy axes of DyIII in 2 are roughly aligned along alkoxido-type O atoms (O3 and O3a), which is slightly longer than other Dy-O distances.