title: Studies of magnetic properties and HFEPR of octanuclear manganese single-molecule magnets.
abstract: A new octanuclear manganese cluster [Mn(8)(Hpmide)(4)O(4)(EtCOO)(6)](ClO(4))(2) (1) is achieved by employing Hpmide as the ligand, and this paper examines the synthesis, X-ray structure, high-field electron paramagnetic resonance (HFEPR), magnetization hysteresis loops and magnetic susceptibilities. Complex 1 was prepared by two different methods, and hence, was crystallized in two space groups: P3(2)21 for 1a and P3(1)21 for 1b. Each molecule possesses four Mn(II) and four Mn(III) ions. The metal-oxo framework of complex 1 consists of three face-sharing cubes with manganese ions on alternate corners. The four Mn(III) cations have their Jahn-Teller elongation axes roughly parallel to the c axis of the crystal lattice. The dc magnetic susceptibility measurements reveal a spin-frustration effect in this compound. The ac magnetic susceptibilities, as well as the magnetization hysteresis measurements, clearly establish that complex 1a is a single-molecule-magnet (SMM) with a kinetic energy barrier (10.4 cm(-1)) for spin reversal. HFEPR further confirms that complex 1a is a new SMM with a magnetoanisotropy and quantized energy levels. However, interpretation of the complete set of measurements in terms of a well defined spin ground state is not possible due to the spin frustration.
authors.affiliation: Department of Chemistry, Fu Jen Catholic University, Hsinchuang, Taipei, 24205, Taiwan, Republic of China.
authors.forename: Che-Chih
authors.initials: CC
authors.lastname: Wu
authors.forename: Saiti
authors.initials: S
authors.lastname: Datta
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wernsdorfer
authors.forename: Gene-Hsian
authors.initials: GH
authors.lastname: Lee
authors.forename: Stephen
authors.initials: S
authors.lastname: Hill
authors.forename: En-Che
authors.initials: EC
authors.lastname: Yang