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Udo Steiner 《无机化学与普通化学杂志》2005,631(9):1706-1714
On the Chemical Vapor Transport of Ternary Transition Metal‐ and Earth Alkaline Tungstates MWO4 with Chlorine The chemical vapor transport of transition metal tungstates MWO4 (M=Mn, Co, Ni, Cu, Zn, Cd) was investigated in dependence on mean transport temperature (923 K to 1223 K) and amount of transport agent Cl2. All tungstates migrate in a temperature gradient ΔT = 100 K from the region of higher temperature to the lower temperature with migration rates of 0.5 to 8 mg/h depending on experimental conditions. The transport behaviour was determined by continuous measurement of mass change during the transport experiments. The results were compared to thermo chemical calculations and the influence of moisture content discussed in detail. MgWO4 migrates under the influence of Cl2 in a temperature gradient 1273 K to 1173 K (migration rate 0.7 mg/h), CaWO4 and SrWO4 in a temperature gradient 1423 K to 1323 K (migration rate <0.1 mg/h). 相似文献
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2, 4‐Dimethylpenta‐1, 3‐diene and 2, 4‐Dimethylpentadienyl Complexes of Rhodium and Iridium The complexes [(η4‐C7H12)RhCl]2 ( 1 ) (C7H12 = 2, 4‐dimethylpenta‐1, 3‐diene) and [(η4‐C7H12)2IrCl] ( 2 ) were obtained by interaction of C7H12 with [(η2‐C2H4)2RhCl]2 and [(η2‐cyclooctene)2IrCl]2, respectively. The reaction of 1 or 2 with CpTl (Cp = η5‐C5H5) yields the compounds [CpM(η4‐C7H12)] ( 3a : M = Rh; 3b : M = Ir). The hydride abstraction at the pentadiene ligand of 3a , b with Ph3CBF4 proceeds differently depending on the solvent. In acetone or THF the “half‐open” metallocenium complexes [CpM(η5‐C7H11)]BF4 ( 4a : M = Rh; 4b : M = Ir) are obtained exclusively. In dichloromethane mixtures are produced which additionally contain the species [(η5‐C7H11)M(η5‐C5H4CPh3)]BF4 ( 5a : M = Rh; 5b : M = Ir) formed by electrophilic substitution at the Cp ring, as well as the η3‐2, 4‐dimethylpentenyl compound [(η3‐C7H13)Rh{η5‐C5H3(CPh3)2}]BF4 ( 6 ). By interaction of 2, 4‐dimethylpentadienyl potassium with 1 or 2 the complexes [(η4‐C7H12)M(η5‐C7H11)] ( 7a : M = Rh; 7b : M = Ir) are generated which show dynamic behaviour in solution; however, attempts to synthesize the “open” metallocenium cations [(η5‐C7H11)2M]+ by hydride abstraction from 7a , b failed. The new compounds were characterized by elemental analysis and spectroscopically, 4b and 5a also by X‐ray structure analysis. 相似文献
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