| Abstract |
A tetravalent uranium compound with a radical azobenzene ligand, namely, [\(SiMe2NPh)(3)-tacn\U-IV(eta(2)-N2Ph2 center dot)] (2), was obtained by one-electron reduction of azobenzene by the trivalent uranium compound [U-III\(SiMe2NPh)(3)-tacn\] (1). Compound 2 was characterized by single-crystal X-ray diffraction and H-1 NMR, IR, and UV/Vis/NIR spectroscopy. The magnetic properties of 2 and precursor 1 were studied by static magnetization and ac susceptibility measurements, which for the former revealed single-molecule magnet behaviour for the first time in a mononuclear UIV compound, whereas trivalent uranium compound 1 does not exhibit slow relaxation of the magnetization at low temperatures. A first approximation to the magnetic behaviour of these compounds was attempted by combining an effective electrostatic model with a phenomenological approach using the full single-ion Hamiltonian. |
