Metal vapor reaction chemistry

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. 

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). 

Analysis of possible structures and reaction pathways in reactions 1-4 led to various model structures for these complexes (9t25). Some of these involved C-H activation of the substituents attached to the unsaturated carbon atoms. To test the validity of these models, two additional types of metal vapor reactions were examined. In one case, reactions with simpler unsubstituted hydrocarbons were examined. In another case, substrates ideally set up for oxidative addition of C-H to the metal center were examined. As described in the following paragraphs, both of these approaches expanded the horizons of organolanthanide chemistry. 

These metal vapor-derived nanostructured systems are valuable catalytic precursors for a wide range of reactions of great interest in fine chemistry. 

Asymmetric Synthesis by Homogeneous Catalysis Metal Vapor Synthesis of Transition Metal Compounds Metathesis Polymerization Processes by Homogeneous Catalysis Oligomerization Polymerization by Homogeneous Catalysis Organic Synthesis Using Metal-mediated Metathesis Reactions Titanium Inorganic Coordination Chemistry. 

One of the earliest studies of zero valent lanthanide metal vapor chemistry involved the matrix isolation reaction of the metals with CO (73, 74). Based on infrared data, a variety of zero valent metal carbonyl complexes, Ln(CO) , n = 1-6, were postulated. These were not preparative scale experiments, however, and the reaction products were not stable except at very low temperature. Hence, unambiguous confirmation of the formula and structure of these complexes could not be obtained. 

Tris(acetylacetonato-<9,<9) iridium(III) is a coordinatively saturated, stable species that has been examined spectroscopically1,2 and used in metal vapor deposition studies.3 4 Removal of one acac ligand (acac = acetylacetonato or 2,4-pentanedionate) generates a family of bis-(acac-<9,<9) iridium(III) complexes exhibiting rich coordination chemistry. In 1976, Bennett and Mitchell isolated these (acac-<9,<9)2Ir(III)(R)(L) complexes as intermediates in yielding preparations of the (acac-<9,<9)3Ir(III) complex from the reaction of acetylace-tone with IrCl3.5... 

The alkaline earth metals form a host of unique monovalent free radicals. Most of these molecules can be formed by the laser-driven chemical reactions of metal vapors with a wide variety of organic and inorganic molecules. This photochemical production of new molecules has led to an extensive gas-phase inorganic chemistry and spectroscopy of alkaline earth derivatives. In recent years, the Broida oven source has been displaced by the pulsed molecular beam spectrometer. The chemical dynamics and photochemistry of these new molecules are still at a very early stage of investigation. 

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