Metal organics are compounds containing metals and organic ligands, which would give them solubility in organic solvents or volatiles. Chemical compounds of metal organics contain at least one chemical bond between carbon atoms and metals, including alkaline metals, alkaline earth metals and transition metals, and sometimes extend to include metalloids like boron, silicon and tin. Bonds to "inorganic" carbons (such as carbon monoxide, cyanides, or carbides) are generally considered to be metal organics except for bonds to organyl fragments or molecules. The field of metal organics combines traditional inorganic chemistry and organic chemistry.
Applications
Industry: Metal organics are widely used as commercial catalysts for both homogeneous and stoichiometric reagents. For example, organoaluminium compounds are useful in stoichiometry and also used to catalyze many polymerization reactions. Many semiconductors are made of trimethyl gallium, trimethyl indium, trimethylaluminum, and trimethyl antimony. These volatile compounds are decomposed with ammonia, arsine, phosphine and related hydrides on heated substrates by the metal-organic vapor phase epitaxy (MOVPE) process in light-emitting diode (LED) production.
Organic chemistry: Negishi coupling is the powerful carbon-carbon bond-forming cross-coupling reaction which combines an organohalide and an organozinc halide reagent in the presence of a nickel or palladium catalyst. The organic halide reactant may be alkenyl, aryl, allyl, or propargyl. Alkyl zinc coupling with alkyl halides such as bromides and chlorides has also been reported with an active catalyst, such as Pd-PEPPSI precatalyst, which strongly resists the elimination of β-hydride. In this reaction, a diorganic substance or an organozinc halide may be used as a coupling partner. These reagents are among the most effective metal nucleophiles in palladium despite the low reactivity of organic reagents to organic electrophile.
Figure.1. A typical example of a Negishi coupling is amphotericin T1 synthesized by Furstner
Catalysis chemistry: Metal organics are commonly used for catalysis. Major industrial processes include hydrogenation, hydrosilylation, hydrocyanation, olefin metathesis, olefin polymerization, olefin oligomerization, hydrocarboxylation, methanol carbonylation and hydroformylation. Organometallic intermediates are also used in many heterogeneous catalysis processes, similar to those listed above. Almost all processes involving carbon monoxide rely on catalysts. The production of acetic acid from methanol and carbon monoxide is catalyzed by metal carbonyl complexes in the Monsanto process and Cativa process. Most synthetic aldehydes are produced through hydroformylation. The bulk of the synthetic alcohols are also produced by hydrogenation of hydroformylation-derived aldehydes. Similarly, the Wacker process is used in the oxidation of ethylene to acetaldehyde by using the metal organics as catalysts.
In addition, it is assumed that organometallic intermediates are used in Fischer-Tropsch process. Organometallic complexes are also commonly used in small-scale fine chemical synthesis, especially in cross-coupling reactions that form carbon-carbon bonds. Suzuki-Miyaura coupling, Buchwald-Hartwig amination and Sonogashira couplings for aryl amine production with aryl halides are the typical reactions using metal organics as catalysts.
