Substituted group-directed assembly of six coordination compounds based on pyrazole bifunctional ligands

Six new complexes [Mn8(μ4-O)4(phpz)8(MeOH)4]·(MeOH)(H2O) (1) [Co2(HphpzH)(Hphpz)2(phpz)2]·4(MeOH) (2), Ni(Hphpz)2(3), [Ni(Hphpz)2]·H2O (4), [Zn4(pzpy)4Cl4] (5) and [Cu2(pzpy)2(HCO2)2(H2O)2] (6) have been synthesized by hydrothermal reactions of MCl2·4H2O (M = Mn, Co, Ni, Zn or Cu) with 5-(2-hydroxyphenyl)-3-pyrazole (HphpzH) or 2-(1H-pyrazol-3-yl)pyridine (Hpzpy). The complexes were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Complex 1is an octanuclear Mn(III) cluster, complexes 2and 6are binuclear Co(III) and Cu(II), respectively, complexes 3and 4are isomorphous mononuclear species, while complex 5is a tetranuclear Zn(II) cluster. The magnetic behavior of complex 1was investigated. Magnetic susceptibility measurements revealed antiferromagnetic exchange interactions between the metal centers in the clusters. The luminescence properties of the complexes were investigated at room temperature in the solid state.