Butterfly hysteresis loop and dissipative spin reversal in the S=1/2, V15 molecular complex

Time resolved magnetization measurements have been performed on a spin 1/2 molecular complex, so called V$_{15}$. Despite the absence of a barrier, magnetic hysteresis is observed over a timescale of several seconds. A detailed analysis in terms of a dissipative two level model is given, in which fluctuations and splittings are of same energy. Spin-phonon coupling leads to long relaxation times and to a particular "butterfly" hysteresis loop.Comment: LaTeX/RevTeX, 3 figures.Approved for publication in PR

A BUILDING PRINCIPLE OF AMORPHOUS CHALCOGENIDES OF TRANSITION-METALS - THE EXTRUSION OF THE ELECTRON-RICH CLUSTER [RE4S2(SO2)(4)(CN)(10)](8-) FROM A-RE2S7

Müller A, Krickemeyer E, Bögge H, RATAJCZAK H, Armatage A. A BUILDING PRINCIPLE OF AMORPHOUS CHALCOGENIDES OF TRANSITION-METALS - THE EXTRUSION OF THE ELECTRON-RICH CLUSTER [RE4S2(SO2)(4)(CN)(10)](8-) FROM A-RE2S7. ANGEWANDTE CHEMIE-INTERNATIONAL EDITION IN ENGLISH. 1994;33(7):770-773

SPHERICAL MIXED-VALENCE [V15O36]5-, AN EXAMPLE FROM AN UNUSUAL CLUSTER FAMILY

Müller A, Krickemeyer E, Penk M, Walberg HJ, Bögge H. SPHERICAL MIXED-VALENCE [V15O36]5-, AN EXAMPLE FROM AN UNUSUAL CLUSTER FAMILY. ANGEWANDTE CHEMIE-INTERNATIONAL EDITION IN ENGLISH. 1987;26(10):1045-1046

[V19O41(OH)9]8-, AN ELLIPSOID-SHAPED CLUSTER ANION BELONGING TO THE UNUSUAL FAMILY OF V-IV/V-V OXYGEN CLUSTERS

Müller A, Penk M, Krickemeyer E, Bögge H, Walberg HJ. [V19O41(OH)9]8-, AN ELLIPSOID-SHAPED CLUSTER ANION BELONGING TO THE UNUSUAL FAMILY OF V-IV/V-V OXYGEN CLUSTERS. ANGEWANDTE CHEMIE-INTERNATIONAL EDITION IN ENGLISH. 1988;27(12):1719-1721

[MO3(IV)S(S2)6]2- FROM AMORPHOUS MOS3 BY THE REACTION WITH OH- AND R = 0.015 STRUCTURE OF (NH4)2[MO3(IV)S(S2)6].H2O

Müller A, Diemann E, Krickemeyer E, WALBERG HJ, Bögge H, ARMATAGE A. [MO3(IV)S(S2)6]2- FROM AMORPHOUS MOS3 BY THE REACTION WITH OH- AND R = 0.015 STRUCTURE OF (NH4)2[MO3(IV)S(S2)6].H2O. EUROPEAN JOURNAL OF SOLID STATE AND INORGANIC CHEMISTRY. 1993;30(5):565-572.A refined crystal structure determination (R=0.015) of (NH4)2 [Mo3S13] . H2O including H-atom positions of the NH4+ ions is reported. The formation of the cluster anion [Mo3S13]2- from amorphous MoS3, suspended in O2- free aqueous ammonia solution at room temperature, is described. This observation is discussed in terms of triangular sulfide and disulfide bridged Mo3 units regarded as structural features in the amorphous educt

MOS42- AND MOOS32- AS STRUCTURALLY VERSATILE AND BIOCHEMICALLY INTERESTING LIGANDS IN CRYSTALLINE MULTI-NUCLEAR CU-COMPLEXES AND FE-COMPLEXES

Müller A, Bögge H, Tölle HG, JOSTES R, SCHIMANSKI U, DARTMANN M. MOS42- AND MOOS32- AS STRUCTURALLY VERSATILE AND BIOCHEMICALLY INTERESTING LIGANDS IN CRYSTALLINE MULTI-NUCLEAR CU-COMPLEXES AND FE-COMPLEXES. ANGEWANDTE CHEMIE-INTERNATIONAL EDITION IN ENGLISH. 1980;19(8):654-655

Single-crystal neutron structure analysis of (NH4)(21)[H3Mo57V6(NO)(6)O-183(H2O)(18)]center dot 53 H2O

Lutz HD, Nagel R, Mason SA, Müller A, Bögge H, Krickemeyer E. Single-crystal neutron structure analysis of (NH4)(21)[H3Mo57V6(NO)(6)O-183(H2O)(18)]center dot 53 H2O. JOURNAL OF SOLID STATE CHEMISTRY. 2002;165(1):199-205.The crystal structure of (NH4)(21)[H3Mo57V6(NO)(6)O-183 (H2O)(18)] . 53 H2O, a supramolecular heteropoly cluster compound (space group P6(3)/mmc, Z=2, final R1 = 0.1302 (I > 2sigma(I)) for 1745 unique reflections), was redetermined by single-crystal neutron diffraction studies at 20K. The X-ray diffraction results reported in 1994 by Mijller et al. (Z. Anorg. Allg. Chem. 620, 599) are confirmed. Additionally, we could localize many hydrogen positions not found so far and establish a phase transition near 240 K. Many of the ammonium ions, the ligand and hydrate H2O molecules, and the hydroxy group are orientationally disordered, even at 20 K. The central cavity of the structure is built up by two twelve-membered rings consisting of six O-(HO)-O-... hydrogen bonds each. These strong hydrogen bonds are obviously decisive for the stability of the cluster. The hydrate H2O molecules are stronger-hydrogen-bond acceptor groups than the oxoligands of the cluster. (C) 2002 Elsevier Science (USA)