Metal vapor study

Lanthanide metal vapor studies with CO have also been done Slater, J. L. DeVore, T. C. Calder, V. Inorg. Chem. 1973, 12, 1918 1974, 13, 1808. 

Lanthanide metal vapor studies with acetylacetone have also been... 

The interaction of a lanthanide metal with a substrate such as 3-hexyne could occur in several ways 60) by it complex formation, by oxidative addition into a C—H bond, or by reduction involving radical species. Subsequent lanthanide metal vapor studies were designed to test some of these possibilities. Co-condensation of lanthanide metal vapor with reagents containing acidic hydrogen atoms, e.g., terminal alkynes, demonstrated that oxidative addition of C—H was a viable reaction [Eqs. (32) and (33)] 51). These reactions also provided access to a new class of... 

Since the demonstration by Schumacher et al ) of the use of alkali metal vapor inclusion into a supersonic beam to produce clusters, there have been a number of attempts to generalize the approach. It has recently been recognized that instead of high temperature ovens, with their concommitant set of complex experimental problems, an intense pulsed laser beam focused on a target could be effectively used to produce metal atoms in the throat of a supersonic expansion valve. ) If these atoms are injected into a high pressure inert gas, such as helium, nucleation to produce clusters occurs. This development has as its most important result that clusters of virtually any material now can be produced and studied with relative ease. 

We shall focus here on the synthesis of the isocyanide-containing polymer. Several reactions of the polymer with the metal vapors of Cr, Fe and Ni using a matrix-scale modeling technique, as well as synthetic-scale metal vapor methods, are then presented in order to demonstrate the reactivity of the isocyanide groups on the polymer. Finally, preliminary studies of the reactivity of the polymer-based metal complexes are described. 

For detailed characterization and extensive studies of reactivity, multi-gram quantities are still needed and large-scale metal vapor synthetic routes are necessary. The equipment required for this is well-documented (4) and so will not be described in detail here. The principles are those of the Fluid Matrix Technique except that in order to accommodate 10-100 gram of polymer, the coreactant is contained within a rotating flask which serves to provide a continuously renewed film as metal atoms are produced under high vacuum. 

A review of preparative methods for metal sols (colloidal metal particles) suspended in solution is given. The problems involved with the preparation and stabilization of non-aqueous metal colloidal particles are noted. A new method is described for preparing non-aqueous metal sols based on the clustering of solvated metal atoms (from metal vaporization) in cold organic solvents. Gold-acetone colloidal solutions are discussed in detail, especially their preparation, control of particle size (2-9 nm), electrophoresis measurements, electron microscopy, GC-MS, resistivity, and related studies. Particle stabilization involves both electrostatic and steric mechanisms and these are discussed in comparison with aqueous systems. 

Metal vapor chemistry showed that the lanthanides had quite an extensive chemistry with unsaturated hydrocarbons. Some of the early surveys of metal vapor reactions with unsaturated hydrocarbons included some lanthanide metals and showed that reactivity was present for these metals (14-18). Subsequent synthetic studies in which the products were isolated and characterized led to some of the most unusual organolanthanide complexes currently known (19-28). 

The (C Me ) Sm(THF) metal vapor product provided the first opportunity ta see if Smdl) complexes (y =3.5—3.8 Ufi) could be characterized by H NMR spectroscopy (24). Fortunately, the paramagnetism doesn t cause large shifting and broadening of the resonances and hence samarium provides the only Ln(III)/Ln(II) couple in which both partners are NMR accessible. Once the existence and identity of (C Mej- SmdHF) was known, a solution synthesis was developed from KC Me and Sml THF) (44). This system is the preferred preparative route and also provides another soluble organosamarium(II) complex, [(C Me )Sm(THF)2(u-I)]2, under appropriate conditions. This is another xample of how solution studies subsequently catch up to the research targets often identified first in metal vapor reactions. 

When the metals were studied, the release of gases and vapors was observed. For example, Paracelsus reported that when iron was dissolved in sulfuric acid air comes out like a wind. The differentiation of these kinds of air took more than two centuries. Research on the analysis of gases was extremely productive in developing the basic methods to handle and study gases and even paved the way to design techniques for elementary analysis of the constituents of organisms. Thus the study of gases became the second epoch of analytical chemistry it is called the pneumatic age. ... 

Cloke et al. presented the elegant metal-vapor synthesis for the preparation of linear 14 valence-electron complexes [M°(NHC)2] 73 (M = Ni, Pd, Pt) (Fig. 24a) [186]. The method was subsequently improved [187] and the interesting electronic and catalytic properties of Pd° and Pt° biscarbene complexes have been studied in detail [188-191]. 

A thorough study of the metallothermic reduction of CfFj with Li metal vapor (Section II,A) was reported in 1976 (55). From these studies, the three crystal structures of Cf metal and the temperature relationships between them were elucidated, but uncertainties still remained due to the lack of adequate analytical data concerning the level of impurities in the Cf metal studied (55). 

Studies of the radiation emitted by a metallic vapor when it is illuminated by radiation from a cooled arc of that metal have been made for mercury by Wood, Fuchtbauer and others and for mercury, cadmium, lead, bismuth and thallium by Terenin. These results serve either as a verification of the Bohr energy level scheme of an atom or as a means for identification of certain energy levels in an atom whose series relations are unknown. 

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