Synthesis and characterisation of a Ni-4 single-molecule magnet with S-4 symmetry

Ferguson, A., Lawrence, J., Parkin, A., Sanchez-Benitez, J., Kamenev, K.V., Brechin, E.K., Wernsdorfer, W., Hill, S. and Murrie, M. (2008) Synthesis and characterisation of a Ni-4 single-molecule magnet with S-4 symmetry. Dalton Transactions(45), pp. 6409-6414. (doi: 10.1039/b807447j)

Abstract

[Ni4cl4(Hl)(4)] (1) {H2l=hn(Ch2ch2oh)(2)} Has s-4 symmetry and crystallises in the tetragonal space group i4(1)/A. Two exchange couplings are observed between the four ni(Ii) Centres, with j1 = 7.29 Cm(-1) And j2 = -2.08 Cm(-1), Leading to an s = 4 ground state. The ni-4 complex shows the onset of frequency dependent signals in the out-of-phase ac susceptibility below 3 k. In single-crystal measurements carried out using a micro-squid, hysteresis loops are observed below 0.5 K, confirming that 1 shows slow relaxation of magnetisation. The loops are temperature dependent but only weakly sweep rate dependent due to the presence of small intermolecular interactions, which hinder quantum tunnelling. This exchange bias between ni4 molecules is also seen in high-frequency high-field epr measurements, which give the parameters d = -0.75 Cm(-1), B-4 degrees = -6.7 X 10(-5) Cm(-1) And g(Z) = 2.275.

• Item Type: Articles
• Keywords: Bis-tris bridged clusters, complex, complexes, dimer family, ground-state, hysteresis, intermolecular, interactions, iron magnetization, molecule, molecules, parameters, relaxation, s=9/2 single-molecule magnet, single-molecule-magnet, spin state, symmetry, temperature.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Murrie, Professor Mark and Parkin, Dr Andrew
• Authors: Ferguson, A., Lawrence, J., Parkin, A., Sanchez-Benitez, J., Kamenev, K.V., Brechin, E.K., Wernsdorfer, W., Hill, S., and Murrie, M.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Dalton Transactions
• ISSN: 1477-9226