Effect of a pentadentate Schiff base on the helical supramolecular structures of (\mu-alkoxo)(\mu-carboxylato)dicopper(II) complexes

Gupta, Sunita and Mukherjee, Arindam and Nethaji, Munirathinam and Chakravarty, Akhil R (2005) Effect of a pentadentate Schiff base on the helical supramolecular structures of (\mu-alkoxo)(\mu-carboxylato)dicopper(II) complexes. In: Polyhedron, 24 (15). pp. 1922-1928.

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Abstract

Two new asymmetrically dibridged dicopper(II) complexes with apentadentate Schiff base and p-hydroxycinnamate are prepared and structurally characterized by X-ray crystallography. The complexes have an asymmetrically dibridged (mu-alkoxo)(mu-carboxylato)dicopper(II)core with an alkoxo bridge from the Schiff base and the carboxylateshowing a three-atom bridging mode. Variable-temperature magneticstudies show the complexes having an antiferromagnetically coupled spinsystem giving a singlet-triplet energy separation of -160 and-132 $cm^{(-1)}$ for 1 and 2, respectively. Complex 1, with a shorterCu-OR-Cu angle, displays greater antiferromagnetic spin coupling. Besides the Cu-OR-Cu angle, the role of the carboxylate ligand and thesupramolecular structure in the spin coupling phenomena is observed. Complex 1(.)MeOH shows the formation of intermolecular hydrogen bondsinvolving the axial methanol and the pentadentate Schiff base terminaloxygen atom. There is additional hydrogen bonding interactions involving the p-hydroxy group of the carboxylate, the lattice methanol and the terminal oxygen atom. The crystal structure of complex2(.)H(2)O displays the presence of a helical supramolecular structuredue to hydrogen bonding interactions involving the pendant p-hydroxygroup and the bridging oxygen atom of the carboxylate.

Item Type:	Journal Article
Publication:	Polyhedron
Publisher:	Elsevier Ltd
Additional Information:	Copyright for this article belongs to Elsevier Ltd.
Keywords:	Dicopper(II) complex;Schiff base;Crystal structure;Supramolecular helices;Magnetic properties;Hydrogen bonds
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	26 Nov 2007
Last Modified:	19 Sep 2010 04:21
URI:	http://eprints.iisc.ac.in/id/eprint/4081

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