Metal-vapor technique

The metal-vapor technique was applied to cobalt atoms and r-BuC = P (01JOM(635)212). The mixture of products that resulted includes the mixed-ligand sandwiches 170 and 171. Further interaction of complex 170 with [W(C0)5(THF)] leads to the coordination of the W(CO)5-group via the phosphorus heteroatom of the four-membered ring to yield 172. 

The first trifluorosilyl "organometallic compound, bis(trifluorosi-lyDmercury, has been prepared by using the new, metal-vapor technique (35). 

Klabunde has reported limited reactivity toward oxidative addition reactions of carbon halogen bonds with nickel slurries prepared by the metal vaporization technique(65). 

The metal vapor method also has played an important role in the development of organometallic lanthanide chemistry (6-10). This high energy technique demonstrated that the lanthanide metals had a much greater range of organometallic chemistry than had been assumed previously. The metal vapor technique applied to lanthanides identified reasonable new research goals which could subsequently be pursued by solution techniques. Not only the metal vapor reactions. 

Butadiene d4 complexes were obtained (i) from [NbCU(dmpe)2] and magnesium butadiene (equation 87) j706 (ii) by dimerization of ethylene using alkylidenes (equation 88) 707 or (iii) by metal vapor techniques (equation 89), which yielded sublimable methylallyl derivatives.70 Compound (62) could not be prepared by Na/Hg reduction of (22) in the presence of butadiene. Compound (63) is also accessible from [TaH2ClL4] (Scheme 9). 

Cluster compounds with an Aun core can also be synthesized by the metal vaporization technique. Ethanol films containing L and LAuX at... 

Depending on the wavelength of radiation used, irradiation of Co2(CO)g produces either CO dissociation (at 250 nm) or cleavage into Co(CO)4 radicals (at 360 nm). The radical Co(CO)4 (2) itself has been detected by its Raman, infrared, UV-vis, and EPR see Electron Paramagnetic Resonance) spectra. It can be found by EPR when (1) is heated and sublimed on a 77 K cold finger in the EPR cavity, or it can be generated in a matrix at low temperature either by photolysis of (1) or by the metal vapor technique see Metal Vapor Synthesis of Transition Metal Compounds). 

The metal vapor technique, in which a metal is vaporized from a resistively heated tungsten container under high vacuum and is cocondensed with a potential ligand at -125 to -196°C, had proven useful in the synthesis of a variety of unusual low-valent transition metal complexes (67-71). With lanthanide metals, this method not only has generated low oxidation state species, but it has also provided the opportunity to study zero-valent lanthanide chemistry on an atomic/molecular basis for the first time. These studies have been important in identifying new directions in organolanthanide chemistry. 

Co and Ni are normally active for the hydrogenolysis of alkanes, whereas Eu and Yb metal powders prepared by the metal vapor technique are not active under similar reaction... 

Metal vapor techniques provide unique means for cryochemical solid-phase synthesis of metal-containing systems. In this way, metastable compounds, whose existence earlier was only supposed, have been obtained [7]. Besides, cryochemical processes produce stabilized small metal clusters of quantum type, which are the intermediate form of matter between isolated atoms and bulk metal [8, 9]. However, known methods of cryochemical solid-phase synthesis used low-molecular-weight matrices, in which the initial products of such a synthesis can be conserved only at low temperatures, when the matrix is enough rigid to hinder transformation or loss of these products. 

Oxidative addition requires either the use or the in situ generation of a Pd(0) complex. Metal vapor techniques, for instance, have allowed the preparation of nonligated polymeric aryl-Pd complexes, (CgF5PdX) , where X = Cl or The higher thermal stability of the perfluoroorganylpalladium complexes as compared with their ordinary organopalladium derivatives is once again clearly indicated (vide infra). 

Metal vapor techniques have provided chemists with a very versatile route for the production of a wide range of nanostructure metal colloids on a preparative laboratory scale. 2-i59i -piie of metal vapor techniques is limited because the... 

Gas-phase studies using laser vaporization techniques have provided evidence for Ni-benzene compounds displaying so-called rice-ball structures in which one or more Ni center is completely surrounded by benzene molecules. On the other hand, 77 -interactions predominate in (Tr-arene)-Ni compounds, which are often prepared by metal-vapor techniques or in liquid nitrogen matrices. In a few cases, more conventional synthetic routes have been used for the preparation of (Tr-arene)-Ni compounds. For instance, the reaction of Ni(ii) salts with various sources of aryl ligands 05X5 (X = F zor Cl) in the presence of arene sources (usually an aromatic solvent) gives Ni(G6X5)2(r7 -arene). ... 

The syntheses are related to the ones used for the mono-ene complexes. The metal-vapor technique of synthesis involving very low pressure of metals has been used to make binary complexes such as molybdenum (0) tris-1,3-butadiene. 

It works well for instance with the metal-vapor technique that consists in vaporizing metal atoms at low temperature and pressure. In fact, the most practical method for the syntheses of ferrocene and its derivatives consists in the in situ deprotonation of cyclopentadiene pKa = 15) or its derivative by diethylamine, the solvent, in the presence of anhydrous FeCl2 or FeCls. The iron chloride can be generated in situ from iron powder and the amine chlorohydrate ... 

A metal vapor technique provides a very interesting route to the preparation of Sm(II) or Yb(II) organometallic species. Thus W.J. Evans et al. (1980, 1981a, 1982) were able to prepare several substituted dicyclopentadienyl samarium and ytterbium complexes. Sm(C5Mes)2 was the first known soluble divalent organosamarium complex. 

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