Magneto-structural study on a tetracopper(II) Schiff base complex stabilizing a decanuclear water aggregate

Naik, Sunil G and Mukherjee, Arindam and Raghunathan, Rajamani and Nethaji, Munirathinam and Ramasesha, Suryanarayanasastry and Chakravarty, Akhil R (2006) Magneto-structural study on a tetracopper(II) Schiff base complex stabilizing a decanuclear water aggregate. In: Polyhedron, 25 (10). pp. 2135-2141.

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Abstract

A new tetranuclear copper(II) complex [Cu4L2(3-ppz)(2)] (1) has been prepared from the reaction of [Cu2LBr] and 3-phenylpyrazole (3-ppz), where H3L is a pentadentate Schiff base N,N'-(2-hydroxypropane1,3 diyl)bis(salicylaldimine). The complex as 1 center dot 6H(2)O has been structurally characterized by X-ray crystallography. The structure shows the presence of a tetranuclear copper(II) complex with a core showing Cu center dot center dot center dot Cu distances in the range of 3.261(1)-3.492(1) angstrom. The tetrameric complex is formed from the self-assembly of two dimeric {Cu2L}(+) units in the presence of two anionic 3-ppz ligands as linkers. The alkoxo oxygen atoms bind three copper(II) centers giving two equatorial and one axially elongated Cu-O bond. The variable temperature magnetic susceptibility data in the range 300-17 K show antiferromagnetic spin-spin coupling giving magnetic moments of 3.3 mu(B) at 300 K and 0.56 mu(B) at 17 K for the Cu-4 unit, theoretical fitting to the magnetic data gives J values of -86.3, -47.32 and 11.13 cm(-1) with a diamagnetic ground state. The crystal structure shows the presence of two complexes and 12 water molecules in the unit cell belonging to the triclinic space group P (1) over bar. Among them, 10 water molecules form an aggregate in which six water molecules are in a chair conformation of the cyclohexane-type with two water dimers hydrogen bonded to the cyclic structure. The discrete decameric water assembly is anchored onto the metalloorganic host involving four phenoxo oxygen atoms of two Cu-4 Units and four water molecules of the cyclic chair hexameric unit through hydrogen bonding interactions.

Item Type:	Journal Article
Publication:	Polyhedron
Publisher:	Elsavier
Additional Information:	Copyright of this article belongs to Elsavier.
Keywords:	Tetracopper(II) complex;Crystal structure;Magnetic properties; Decameric water aggregate;Supramolecular assembly;Schiff base.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	31 Mar 2009 07:01
Last Modified:	19 Sep 2010 05:00
URI:	http://eprints.iisc.ac.in/id/eprint/18080

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