Organometallic compounds, molecular

Landis C R, D M Root and T Cleveland 1995. Molecular Mechanics Force Fields for Modeling Inorgani and Organometallic Compounds. In Lipkowitz K B and D B Boyd (Editors). Reviews in Compute tional Chemistry Volume 6. New York, VCH Publishers, pp. 73-148. 

The isotope patterns for two simple organometallic compounds in the molecular ion region (a) dimethylmercury and (b) dimethylplatinum. The seven isotopes of mercury show clearly and appear quite different from the six isotopes of platinum. Since there are only two carbon atoms, the contribution from C is negligible. 

Organometallic Compounds. Certain zirconium organometaUic compounds are highly reactive toward low molecular weight unsaturated... 

In recent years this simple picture has been completely transformed and it is now recognized that the alkali metals have a rich and extremely varied coordination chemistry which frequently transcends even that of the transition metals. The efflorescence is due to several factors such as the emerging molecular chemistry of lithium in particular, the imaginative use of bulky ligands, the burgeoning numbers of metal amides, alkoxides, enolates and organometallic compounds, and the exploitation of multidentate... 

The processes of reversible adsorption of the coordination" inhibitors (including the adsorption of organometallic compounds) result in an increase in the lifetime of the transition metal-carbon bond. It is possible that due to this, in the case of propylene polymerization by two-component catalysts based on TiCU, at low temperatures a long-term increase of molecular weight with time was observed (192,193). 

By coincidence, the oxygen problem is related to our present question. In the late 18th century, molecular oxygen (02) was a revolutionary discovery for chemists because of its involvement in oxidation, and because of the demonstration that a gas reacts chemically with liquids and solids. On the other hand, nitrogen gas (N2) is, as was already known at that time, inert towards most other chemicals, in particular towards all purely organic compounds (i. e., not organometallic compounds). 

Study of the recoil chemistry of organometallic compounds for its own sake, began really in 1955 with the publication of a study (56) by Mad-dock and Sutin on neutron activation of triphenylarsene. Since this time, most of the published work has been focussed on those radioactive atoms which did not permanently escape their ligands. Thus, in one way or another, they end up in molecular form. It is with these that this review is largely concerned. 

More recent studies (4,10) have shown that various acids and organometallic compounds can serve as catalysts for the preparation of II. The advantages include lower polymerization temperatures, higher yields, lower molecular weights, and the use of conventional large scale equipment. Examples include bulk polymerizations using H 0 (11), Et Al Cl (12), CrCl,.6H 0 (13), (C,H 0) P0-BC1, (14 , polyphosphoric acid... 

Other organometallic compounds of aluminum include the alkyl hydrides, R2A1H. Molecular association of these compounds leads to cyclic tetramers. When the dimeric and trimeric compounds are dissolved in a basic aprotic solvent, the aggregates separate as a result of formation of bonds between A1 and the unshared pair of electrons on the solvent molecule. Toward Lewis bases such as trimeth-ylamine, aluminum alkyls are strong Lewis acids (as are aluminum halides). 

MeSnCl3, Me2SnCl2, MejSnCI 13C and 119Sn NMR. The molecular structure and preferred orientation of die organometallic compounds dissolved in liquid crystals was examined. Strong effects of Lewis acid-base interactions were observed. 155... 

Equations 10 and 11 indicate that the redox potential of the HQ/BQ couple is shifted in the negative direction when ti6-chemisorbed but shifted in the positive direction when 2,3-ti2-bonded. This orientation-dependent shift in redox potential is not unexpected by analogy with molecular organometallic compounds. For example, the redox potential for the reversible, one-electron reduction of duroquinone in acetonitrile is shifted from -0.90 V (vs. SCE) to -0.69 V in bis (duroquinone) Ni (0) and to -1.45 V in (1,5 — cyclooctadiene) (duroquinone)Ni (0) (22.) ... 

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