Adipate as a tetradentate bridging ligand: Synthesis, structure and properties of Cu(II) and Ni(II) compounds with 2,2 '-dipyridylamine as a terminal co-ligand - Archive ouverte HAL
Article Dans Une Revue Polyhedron Année : 2014

Adipate as a tetradentate bridging ligand: Synthesis, structure and properties of Cu(II) and Ni(II) compounds with 2,2 '-dipyridylamine as a terminal co-ligand

Résumé

The synthesis, characterization, single crystal structures and physical properties of the compounds [Cu2(dpa)2(adp)2](H2O)2 (1) and [Ni2(dpa)2(adp)]Cl2 (2), in which dpa = 2,2′-dipyridylamine; adp = adipate(2−) anion, are presented. In both dinuclear compounds the dpa is chelating bidentately, whereas adipate acts as a tetradentate bridge between the 2 metal ions, using both carboxylate oxygen atoms as a chelate. The Cu(II) compound has 2 bridging adipate dianions, whereas the Ni(II) compound has a single bridging adipate(2−); in the latter case the charge of the dinuclear unit is compensated by 2 lattice chloride anions. The N–H of the dpa donates an intermolecular H bond to neighboring molecules; i.e. to the carboxylates for the Cu compound and to the lattice chlorides for the Ni one. In both compounds the metal ions are in a distorted octahedral geometry, and diffuse reflectance spectra agree with this geometry. The Ni⋯Ni contact distance is very long (1089.3 pm). The EPR spectrum of the Cu(II) compound shows a broad signal, and no hyperfine signals are resolved; also no spin = 1 signals are seen, which is in agreement with the very long dinuclear Cu⋯Cu contact distance (831.7 pm). Magnetic susceptibility measurements of the Cu compound down to 5 K show a very weak ferromagnetic coupling with a magnetic moment (per Cu) increasing from 1.73 B.M. (room T) to 1.88 B.M. (at 5 K).

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Chimie
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Dates et versions

hal-01086017 , version 1 (21-11-2014)

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Zouaoui Setifi, Fatima Setifi, Mohamed Ghazzali, Malika El-Ghozzi, Daniel Avignant, et al.. Adipate as a tetradentate bridging ligand: Synthesis, structure and properties of Cu(II) and Ni(II) compounds with 2,2 '-dipyridylamine as a terminal co-ligand. Polyhedron, 2014, 75, pp.68-72. ⟨10.1016/j.poly.2014.03.014⟩. ⟨hal-01086017⟩
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