Reactions of a Coordination Polymer Based on the Triangular Cluster [Cu₃(μ₃-OH)(μ-pz)₃]²⁺ with Strong Acids. Crystal Structure and Supramolecular Assemblies of New Mono-, Tri-, and Hexanuclear Complexes and Coordination Polymers

A series of mono-, tri-, hexanuclear compounds, and coordination polymers were obtained from the reaction of [Cu3(μ3-OH)(μ-pz)3(MeCOO)2(Hpz)], 1, (Hpz = pyrazole) with H2SO4, H3PO4, HClO4, HNO3, CF3COOH, and CF3SO3H. The trinuclear [Cu3(μ3-OH)(μ-pz)3(SO4)(Hpz)3]·H2O, 2t, forms a one-dimensional coordination polymer through bridging SO42−. The mononuclear [Cu(H2PO4)2(Hpz)4], 3m, is instead the unique (pure) compound isolated in our conditions from the reaction of 1 with H3PO4, whereas both [Cu(ClO4)2(Hpz)4], 4m, and [{Cu3(μ3-OH)(μ-pz)3(ClO4)(Hpz)3}2(μ2-ClO4)2], 4h, have been isolated from the reaction with aqueous HClO4, the latter being a hexanuclear species formed by two trinuclear triangular units connected through two bridging perchlorates. Moreover, the three already reported species [Cu3(μ3-OH)(μ-pz)3(NO3)(μ3-NO3)(Hpz)2], 5t, [{Cu3(μ3-OH)(μ-pz)3(NO3)(Hpz)3}2(μ2-NO3)2], 5h, and [Cu(NO3)2(Hpz)4], 5m, are formed in the reaction of 1 with HNO3. Three pure fractions, containing crystals of the trinuclear [Cu3(μ3-OH)(μ-pz)3(CF3COO)2(Hpz)2], 6t, and two mononuclear adducts, [Cu(CF3COO)2(HPz)4], 6m(a), and [Cu(CF3COO)2(Hpz)2], 6m(b), have been isolated when 1 was reacted with aqueous CF3COOH. Analogously, in the reaction of 1 with CF3SO3H, three different species were obtained, the mononuclear [Cu(CF3SO3H)2(Hpz)4], 7m, the trinuclear [Cu3(μ3-OH)(μ-pz)3(CF3SO3)2(Hpz)3]·H2O, 7t, and the hexanuclear [{Cu3(μ3-OH)(μ-pz)3(Hpz)3}{Cu3(μ3-O)(μ-pz)3(Hpz)3}](CF3SO3)3, 7h, where the two trinuclear units are strongly bonded through an unequally shared H-bond involving (μ3-OH) and (μ3-O) [O···O 2.54(1) Å, O(2)−H(2)···O(1) 180°]. All compounds were fully characterized by single-crystal X-ray diffraction determinations, UV−vis and IR spectra, electrospray ionization mass spectrometry, and magnetic susceptibility measurements.