New Coordination Polymers and Porous Supramolecular Metal Organic Network Based on the Trinuclear Triangular Secondary Building Unit [Cu₃(μ₃‑OH)(μ-pz)₃]²⁺ and 4,4′-Bypiridine. 1°

Abstract

The trinuclear triangular Cu^II complex [Cu₃(μ₃-OH)­(μ-pz)₃(HCOO)₂(Hpz)₂] (Hpz = pyrazole) reacts with 4,4′-bipyridine (bpy) yielding a two-dimensional (2D) waved sheets, two three-dimensional (3D) coordination polymers (CPs), as well as a hexanuclear Cu^II cluster, depending on the reagent ratios and reaction conditions. Single crystal X-ray diffraction (XRD) determinations point out that, while CPs crystal structures are not porous, the hexanuclear Cu^II clusters are packed in the solid state generating a stable porous 3D supramolecular network, where two kinds of perpendicular, hydrophobic channels (ca. 4.83 × 5.86 Ų and 4.99 × 4.79 Ų, corresponding to the 24.7% of the total crystal volume) are present. In the “as-synthesized” compound, channels of one kind are empty, while the other ones are occupied by guest bpy molecules which can be removed by soaking the crystals in suitable solvents (benzene, toluene, <i>c</i>-hexane) maintaining intact the crystal skeleton. Moreover, two of the above complexes act as catalysts (or catalyst precursors) in the peroxidative oxidation of cyclohexane