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A Windmill-Shaped Hexacopper(II) Molecule Built Up by Template Core-Controlled Expansion of Diaquatetrakis(μ2-adeninato-N3,N9)dicopper(II) with Aqua(oxydiacetato)copper(II)

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journal contribution
posted on 23.01.2006, 00:00 authored by Josefa María González-Pérez, Carolina Alarcón-Payer, Alfonso Castiñeiras, Tiziana Pivetta, Luis Lezama, Duane Choquesillo-Lazarte, Guido Crisponi, Juan Niclós-Gutiérrez
The windmill-shaped hexanuclear copper(II) cluster {(H2O)2Cu23-(Ade)4[Cu(oda)(H2O)]4}·6H2O (1-o) has been synthesized in aqueous medium by in situ core-controlled expansion of the neutral building block Cu22-N3,N9-Ade)4(H2O)2 (2) with Cu(oda)(H2O) (3-o) (Ade = adeninato(1−) and oda = oxydiacetato(2−) ligands). Crystal data for 2-b (2·5H2O):  triclinic, space group P1̄; a = 9.374(1), b = 9.440(1), c = 10.326(1) Å; α = 78.72(1), β = 76.77(1), γ = 63.51(1)°; final R1 = 0.059; T = 100(2) K. Crystal data for 1-o:  monoclinic, space group P21/n; a = 15.203(2), b = 10.245(1), c = 19.094(2) Å; β = 101.61(1)°; final R1 = 0.049; T = 293(2) K. The X-shaped hexanuclear molecule consists of a central core (2) and four terminal arms (3-o) linked together by bridging μ3-N3,N7,N9-Ade ligands. There are three crystallographic independent metal atoms (two terminals, one central). All Cu(II) atoms exhibit a 4 + 1 coordination, of which one is an aqua apical ligand. The basal coordination sets complete the CuN4 + O or CuO3N + O chromophores for the central or terminal metal atoms, respectively. Thermal stability and spectral and magnetic properties were also studied. Analogous compounds to 1-o with tridentate or tripodal tetradentate ligands L2-, instead of oda, have also been synthesized.