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|Type:||Artigo de periódico|
|Title:||Synthesis, Crystal Structure And Magnetic Properties Of A New Dinuclear Copper(ii) Amino Acid Complex [cu2(l-arg)2(μ-hpo4-o)(μ-hpo4-o,o′)(μ-oh)]- · (h3o)+ · (h2o)6|
|Abstract:||A novel dinuclear copper(II) complex with the amino acid l-arginine (l-arg), with mono and bidentate HPO4 2- oxoanions and an OH- anion. [Cu2(l-arg)2(μ-HPO4-O)(μ-HPO4-O,O′)(μ-OH)]- · (H3O)+ · 6H2O (1) was prepared and its structure was determined by X-ray diffraction methods. The two independent copper ions are in a distorted square pyramidal coordination, each bonded to one l-arginine molecule. These two Cu(l-arg) units are bridged by two monoatomic equatorial-apical oxygen ligands belonging to a monodentate hydrogenphosphate group, and to the hydroxyl group. The copper ions in the dinuclear unit at d = 3.1948(8) Å are also connected by two equatorial oxygen belonging to a bidentate hydrogenphosphate. This dinuclear character and bridging scheme, not common for metal-amino acid compounds, is a consequence of the properties of the phosphate anions. The magnetic susceptibility at temperatures between 2 and 300 K and the isothermal magnetization curves at T = 2.29(1) K with applied fields up to 9 T were measured. The magnetic data indicate an antiferromagnetic intradinuclear exchange coupling J/kB = -3.7(1) K and using a molecular field approximation we estimated a weaker ferromagnetic interaction J′/kB ∼ 0.3 K between neighbour dinuclear units. © 2007 Elsevier Ltd. All rights reserved.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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