Copper(II) α-hydroxycarboxylate complexes of bis(2-pyridylcarbonyl)amine ligand: From mononuclear complex to one-dimensional coordination polymer

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• 作者：Partha Halder ; Ennio Zangr ; o ; Tapan Kanti Paine
• 关键词：Copper ; Hydroxy acids ; Hydrogen bonds ; Coordination polymer ; Solid-state structure
• 刊名：Polyhedron
• 出版年：2010
• 出版时间：13 January 2010
• 年：2010
• 卷：29
• 期：1
• 页码：434-440
• 全文大小：558 K

文摘

The coordination geometry and supramolecular structures of three copper(II) complexes of two α-hydroxycarboxylates and one α-methoxycarboxylate with nitrogen donor co-ligands are discussed. The complexes have been characterized by elemental analysis, ESI-MS, IR and electronic spectroscopy, thermogravimetric analysis and magnetic measurements. The X-ray structure analysis of all the complexes, namely [(BPCA)Cu^II(MA)] (1), [(BPCA)Cu^II(MPA)(H₂O)] (2) and [(BPCA)Cu^II(BA)]_n (3), where BPCA = bis(2-pyridylcarbonyl)amidate, MA = racemic mandelate, MPA = racemic α-methoxy phenylacetate and BA = benzilate anion, shows the copper(II) ion in a distorted square-pyramidal geometry. In 1 the mandelate anion is coordinated to the copper(II) center in a bidentate fashion while in 2 the α-methoxycarboxylate is monodentate. In both cases a one-dimensional supramolecular array is formed through hydrogen bonds: the mononuclear units are directly connected in 1 by the MA hydroxyl group, whereas in 2 is the coordinated water that operates as H donor towards the MPA carboxylate group and the BPCA carbonyl oxygens of nearby complexes. In 3 the benzilate anion, acting as bridging ligand between copper ions, gives rise to a one-dimensional coordination polymer. In the latter, intra- and inter-chain ππ stacking interactions between pyridines and one phenyl ring of benzilate anions are observed in the packing.