title: Highly anisotropic exchange interactions in a trigonal bipyramidal cyanide-bridged Ni(II)3Os(III)2 cluster.
abstract: This article is a part of our efforts to control the magnetic anisotropy in cyanide-based exchange-coupled systems with the eventual goal to obtain single-molecule magnets with higher blocking temperatures. We give the theoretical interpretation of the magnetic properties of the new pentanuclear complex {[Ni(II)(tmphen)(2)](3)[Os(III)(CN)(6)](2)} x 6 CH(3)CN (Ni(II)(3)Os(III)(2) cluster). Because the system contains the heavy Os(III) ions, spin-orbit coupling considerably exceeds the contributions from the low-symmetry crystal field and exchange coupling. The magnetic properties of the Ni(II)(3)Os(III)(2) cluster are described in the framework of a highly anisotropic pseudo-spin Hamiltonian that corresponds to the limit of strong spin-orbital coupling and takes into account the complex molecular structure. The model provides a good fit to the experimental data and allows the conclusion that the trigonal axis of the bipyramidal Ni(II)(3)Os(III)(2) cluster is a hard axis of magnetization. This explains the fact that in contrast with the isostructural trigonal bipyramidal Mn(III)(2)Mn(II)(3) cluster, the Ni(II)(3)Os(III)(2) system does not exhibit the single-molecule magnetic behavior.
authors.affiliation: Institute of Applied Physics of the Academy of Sciences of Moldova, Academy str. 5, Chisinau MD-2068, Moldova. andrew.palii@uv.es
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Palii
authors.forename: Oleg S
authors.initials: OS
authors.lastname: Reu
authors.forename: Sergei M
authors.initials: SM
authors.lastname: Ostrovsky
authors.forename: Sophia I
authors.initials: SI
authors.lastname: Klokishner
authors.forename: Boris S
authors.initials: BS
authors.lastname: Tsukerblat
authors.forename: Matthew
authors.initials: M
authors.lastname: Hilfiger
authors.forename: Michael
authors.initials: M
authors.lastname: Shatruk
authors.forename: Andrey
authors.initials: A
authors.lastname: Prosvirin
authors.forename: Kim R
authors.initials: KR
authors.lastname: Dunbar
mesh_terms: D016880:Anisotropy; D008280:Magnetics; D008958:Models, Molecular; D009532:Nickel / Q000737:chemistry*; D009570:Nitriles / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D009992:Osmium / Q000737:chemistry*; D013696:Temperature
chemical_list: D009570:Nitriles; D009942:Organometallic Compounds; D009992:Osmium; D009532:Nickel