Three-Dimensional Mixed-Ligand Coordination Polymers with Ferromagnetically Coupled Cyclic Tetranuclear Copper(II) Units Bonded by Weak Interactions

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• 作者：Susana Balboa ; Joaqu铆n Borr谩s ; Pilar Brandi ; Rosa Carballo ; Alfonso Casti帽eiras ; Ana B. Lago ; Juan Nicl贸s-Guti茅rrez ; Jose A. Real
• 刊名：Crystal Growth & Design
• 出版年：2011
• 出版时间：October 5, 2011
• 年：2011
• 卷：11
• 期：10
• 页码：4344-4352
• 全文大小：983K
• 年卷期：v.11,no.10(October 5, 2011)
• ISSN：1528-7505

文摘

The complexes {[Cu(HGLYO)(NO<sub>3sub>)(bpy)]路H<sub>2sub>O}<sub>4sub> (1), {[Cu(HGLYO)(NO<sub>3sub>)(phen)]路H<sub>2sub>O}<sub>4sub> (2), and [Cu(HLACO)(ClO<sub>4sub>)(phen)]<sub>4sub> (3) (bpy is 2,2鈥?bipyridine, phen is 1,10-phenanthroline, HGLYO is monoanionic glycolate, and HLACO is monoanionic lactate) have been synthesized and their crystal structures were determined by X-ray diffraction analysis. The thermal behavior and IR, electronic and electron paramagnetic resonance (EPR) spectra are also reported. The structures of compounds 1鈥?b>3 consist of cyclic tetrameric units in which the copper(II) ions are connected by carboxylate groups in an anti-syn conformation. The hydroxycarboxylates, diimine ancillary ligands, and crystallization water molecules, when present, have a significant influence on the crystal structures through weak interactions such as hydrogen bonding and 蟺鈥撓€ stacking. These interactions mainly contribute to the stabilization of the overall supramolecular structures, which contain rectangular voids of different dimensionality. Magnetic measurements in the temperature range 1.8鈥?00 K showed that compounds 1 and 2 are ferromagnetic. The J values obtained were 3.2 cm<sup>鈥?sup> for 1 and 3.3 cm<sup>鈥?sup> for 2. An electrochemical study for complexes 1 and 2 by cyclic voltammetry in dimethylformamide solutions showed the irreversible nature of the electrode process.