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Synthesis, Structure and Magnetic Properties of a Novel Linear Cu II ‐Trimer Complex

2005; Wiley; Volume: 2005; Issue: 22 Linguagem: Inglês

10.1002/ejic.200500538

1099-0682

В. А. Пащенко, B. Brendel, B. Wolf, Michael Lang, Konstantin А. Lyssenko, Olga I. Shchegolikhina, Yulia A. Molodtsova, Larisa Zherlitsyna, Norbert Auner, Florian Schütz, Marcus Kollar, Peter Kopietz, N. Harrison,

Metal complexes synthesis and properties

Abstract A new hexanuclear copper( II ) sandwich complex based on two 10‐membered macrocyclic phenylsiloxanolate ligands, {Cu 6 [(C 6 H 5 SiO 2 ) 5 ] 2 (OH) 2 (C 10 H 8 N 2 ) 2 } · 4(DMF) · 3(H 2 O) ( 1 ), was synthesized and characterized by single‐crystal X‐ray diffraction and measurements of the magnetic susceptibility and isothermal magnetization. The cluster compound crystallizes in the triclinic system, space group P $\bar {1}$ (No. 2), with a = 14.925(3) Å, b = 16.745(2) Å, c = 23.053(3) Å, α = 83.079(9)°, β = 84.836(13)°, γ = 65.019(17)°, and Z = 2. The unit cell contains two identical molecules, each consisting of six interacting Cu 2+ ( S = 1/2) ions. Within the molecule, the six Cu 2+ ions are arranged in two almost linear, parallel trimers. While pairs of oxygen atoms link the Cu 2+ ions within the trimers, single oxygen atoms residing at the ends of the trimers provide the strongest intertrimer bonds. Magnetic measurements reveal an antiferromagnetic intra trimer exchange interaction, J / k B = 85 K, as the dominant magnetic coupling of the complex. By introducing a weak antiferromagnetic inter trimer coupling, J′/k B = 3.5 K, a satisfactory description of the magnetic behavior over a wide range of temperature and magnetic field is obtained. The departure of the model curves from the data at the lowest available temperature indicates the presence of additional, weak intra ‐ and/or inter molecular interactions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)