Andreas Sieber

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– We report an Inelastic Neutron Scattering (INS) study of the fully deuterated molecular compound K6[V IV 15 As6O42]·9D2O (V15). Due to geometrical frustration, the essential physics at low temperatures of the V15 cluster containing 15 coupled V 4+ (S=1/2) is determined by three weakly coupled spin-1/2 on a triangle. The INS spectra at low-energy allow us(More)
– We report an inelastic neutron scattering (INS) study under a magnetic field on the frustrated molecular spin cluster V15. Several field-dependent transitions are observed and provide a comprehensive understanding of the low-energy quantum spin states. The energy gap 2∆0 ≈ 27(3)µeV between the two lowest S = 1/2 Kramers doublets is unambiguously(More)
The synthesis and structural characterisation of three small nickel(II) cages are reported, all stabilised by pivalate ligands. The magnetic properties of the cages have been studied by a combination of susceptibility measurements and inelastic neutron scattering. For a dinuclear cage, [Ni2(mu-OH2)(O2CCMe3)4(HO2CCMe3)4] 1 the ground state is S=2, with a(More)
We report inelastic neutron scattering (INS) studies on a series of Mn(12) derivatives, [Mn(12)O(12)(O2CC6F5)16(H2O)4]z, in which the number of unpaired electrons in the cluster is varied. We investigated three oxidation levels: z = 0 for the neutral complex, z = -1 for the one-electron reduced species and z = -2 for the two-electron reduced complex. For z(More)
A theoretical concept for setting up 1D magnetic interactions between organic radicals aligned into chains within channels of inclusion compounds is presented by calculating collinear intermolecular binding energies using ab initio methods, followed by a Markov model to predict the characteristic length of chains. Experimentally, inclusion crystals(More)
A new family of tetranuclear Ni complexes [Ni(4)(ROH)(4)L(4)] (H(2)L = salicylidene-2-ethanolamine; R = Me (1) or Et (2)) has been synthesized and studied. Complexes 1 and 2 possess a [Ni(4)O(4)] core comprising a distorted cubane arrangement. Magnetic susceptibility and inelastic neutron scattering studies indicate a combination of ferromagnetic and(More)
We report the synthesis and structural characterisation of a family of finite molecular chains, specifically [{[R(2)NH(2)](3)[Cr(6)F(11)(O(2)CCMe(3))(10)]}(2)] (in which R=nPr 1, Et 2, nBu 3), [{Et(2)NH}(2){[Et(2)NH(2)](3)[Cr(7)F(12)(O(2)CCMe(3))(12)][HO(2)CCMe(3)](2)}(2)] (4), [{[Me(2)NH(2)](3)[Cr(6)F(11)(O(2)CCMe(3))(10)]2.5 H(2)O}(4)] (5) and(More)