Trinuclear Cu(II) complexes containing peripheral ketonic oxygen bridges and a μ3-OH core: steric influence on their structures and existence

Sarkar, Biswarup ; Sinha Ray, Mau ; Drew, Michael G. B. ; Figuerola, Albert ; Diaz, Carmen ; Ghosh, Ashutosh (2006) Trinuclear Cu(II) complexes containing peripheral ketonic oxygen bridges and a μ3-OH core: steric influence on their structures and existence Polyhedron, 25 (16). pp. 3084-3094. ISSN 0277-5387

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Official URL: http://www.sciencedirect.com/science/article/pii/S...

Related URL: http://dx.doi.org/10.1016/j.poly.2006.05.032

Abstract

Two tridentate Schiff bases, HL1(6-amino-3-methyl-1-phenyl-4-azahex-2-en-1-one), and HL2 (6-amino-3,6-dimethyl-1-phenyl-4-azahex-2-en-1-one) on reaction with Cu(II) perchlorate in the presence of triethyl amine yielded two new trinuclear copper(II) complexes, [(CuL1)33-OH)](ClO4)2 (1) and [(CuL2)33-OH)](ClO4)2 • 0.75H2O (2), whereas another tridentate ligand HL3 (7-amino-3-methyl-1-phenyl-4-azahept-2-en-1-one) underwent hydrolysis under the same reaction conditions to result in the formation of a mononuclear complex, [Cu(bn)(pn)ClO4] (3) [where bn = 1-benzoylacetonate and pn = 1,3-propanediamine]. All three complexes have been characterized by X-ray crystallography. For both 1 and 2 the cationic part is trinuclear with a [Cu3OH] core held by three carbonyl oxygen bridges between each pair of copper (II) atoms. The structure of 3 is a monomer with a chelating 1,3-propanediamine and a benzoyl acetone moiety. Magnetic measurements of 1 and 2 have been performed in the 2–300 K temperature range. The experimental data could be satisfactorily reproduced by using an isotropic exchange model, H = −J(S1S2 + S2S3 + S1S3), yielding as best fit parameters: J = −25.6 cm−1, g = 2.21 for 1 and J = −11.2 cm−1, g = 2.10 for 2. The EPR spectra at low temperature could be indicative of spin frustration in complex 1.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Copper Trimers; Schiff Base; X-ray Structure; Magnetic Properties
ID Code:108382
Deposited On:13 Oct 2017 13:08
Last Modified:13 Oct 2017 13:08

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