Antiferromagnetic spin-coupling between MnII and amminium radical cation ligands: models for coordination polymer magnets

Bushby, R.J., Kilner, C., Taylor, N. and Williams, R.A. (2008) Antiferromagnetic spin-coupling between MnII and amminium radical cation ligands: models for coordination polymer magnets. POLYHEDRON, 27 (1). pp. 383-392. ISSN 0277-5387

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Abstract

One and two electron oxidation of the manganese(II) complex [L2Mn(hfac)2] {L = 4'',4'''-di-tert-butyl-2',2'',2'''trimethoxy-{4-(4'-diphenylaminophenyl)pyridine} were studied by ultra violet/ visible/ near infra red spectroscopy, cyclic voltammetry and magnetometry. A one-electron oxidation converts the triarylamine ligand to its radical cation and gives a complex in which the antiferromagnetic coupling between the spin on the ligand and that on the metal J/kb is -1.5 K. In a dilute frozen matrix and at low temperature this behaves as an S = 2 system. A two electron oxidation gives [L2Mn(hfac)2]2.+ which at low enough temperatures behaves as an S = 3/2 system but the spin-coupling between the metal and the ligand is weaker (J/kb = -0.3 K). The weakness of these spin-couplings mean that MnII/amminium radical cation complexes are not promising systems on which to base coordination polymer magnets. The equivalent copper(II) complex [L2Cu(hfac)2] was also investigated but this decomposes when an attempt is made to oxidise the ligand to its amminium radical cation.

Item Type:	Article
Copyright, Publisher and Additional Information:	© 2008 PERGAMON-ELSEVIER SCIENCE LTD . This is an author produced version of a paper published in POLYHEDRON . Uploaded in accordance with the publisher's self archiving policy.
Keywords:	Manganese(II), Copper(II), Molecular magnet, Crystal structures
Academic Units:	The University of Leeds > Faculty of Maths and Physical Sciences (Leeds) > School of Chemistry (Leeds)
Depositing User:	Repository Administrator York
Date Deposited:	04 Jun 2008 08:32
Last Modified:	08 Feb 2013 17:05
Published Version:	http://dx.doi.org/10.1016/j.poly.2007.09.020
Status:	Published
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Refereed:	Yes
Identification Number:	10.1016/j.poly.2007.09.020
Related URLs:	Organisation/Department
URI:	http://eprints.whiterose.ac.uk/id/eprint/3936

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