Reduction of Molybdenum and Tungsten Hexafluorides to the Pentavalent State

[摘要] This thesis presents a study of the behaviour of higher oxidation sta,te fluorides of molybdenum and tungsten towards some reducing agents, ionic iodides or Mo and W metals, in three different solvents SO2, MeCN and CH2Cl2. Chapter One summarises previous studies made of higher oxidation state transition metal fluorides, particularly those of molybdenum and tungsten. It is concerned with the preparations, structures and redox chemical behaviour under different conditions and in different solvents. Chapter Two describes the experimental techniques, for example vibrational spectroscopy or cyclic voltammetry etc. , which were used to complete the present work. In Chapter Three, the redox behaviour of MF6 and MF6 salts (M = Mo, W) towards ionic iodides in CH2Cl2 and SO2 is reported. The reactions between iodides and MF6 are quite straightforward in SO2. The products are identified as MF6 salts on the basis of their infrared spectra. However, in CH2Cl2, although Bu4NI is soluble and reduces MF6 readily to MF6, the alkali metal iodides, Nal and KI are insoluble; as a result these reactions are slow and mcomplete. The iodide Bu4NI cannot reduce MF6 to MF6 2- in these solvents, although a mixture of MoF6 and MoF6 2-salts is obtained from the reaction of an equi-molar mixture of NaMoF6 and Nal in SO2 at -60

[发布机构] University:University of Glasgow

[关键词] Inorganic chemistry