INORGANIC GRIGNARD-REAGENTS - PREPARATION AND THEIR APPLICATION FOR THE SYNTHESIS OF HIGHLY-ACTIVE METALS, INTERMETALLICS, AND ALLOYS

NiCl2, FeCl2, PdCl2, PtCl2, RuCl3, RhCl3, and IrCl3 react with excess amounts of ''active magnesium'' (Mg) or diethylmagnesium (Et(2)Mg) in THF generating soluble bimetallic species with the generalized formul a [M(1)(MgCl)(m) . (MgCl2)(p)], m = 1-3, p = 0-1 (''inorganic Grignard reagents''). In the Ru- and Ir-Mg-Cl systems, it appears that two dif ferent metal Grignard reagents, [Ru(MgCl)(2) . 0.5MgCl(2)] (8a) or [Ir MgCl . MgCl2] (10a) and [M'(MgCl)(3)], M' = Ru (8b) or Ir (10b), can b e prepared through application of Et(2)Mg and Mg respectively. Hydrol ysis or alcoholysis of THF solutions containing the inorganic Grignard reagents deliver finely divided, X-ray amorphous metals M(1) (usually ) hydrogen gas and the corresponding Mg salts. The inorganic Grignard reagents in THF react with metal chlorides M(2)Cl(n) in the molar rati o of n:m with the precipitation of nanoparticulate intermetallics or a lloys M(n)(1)M(m)(2) according to equation n[M(1)(MgC1)(m) . (MgCl2)(p )] + mM(2)Cl(n) --> M(n)(1)M(m)(2) down arrow + (mn + p)MgCl2. The iso lated X-ray amorphous intermetallics or alloys were characterized by F e-57 Mossbauer spectroscopy (where M(2) = Fe), DSC and high resolution TEM. Thermal annealing of the X-ray amorphous bimetallic solids leads in most cases to micro- or nanocrystalline intermetallics or alloys w hich can then be identified through X-ray powder diffraction. Thus the preparation of highly active, nanocrystalline metals, intermetallics, and alloys is possible through solution chemistry via a controlled tw o-step process.