Ionic organometallic compounds

Less electronegative metals, such as sodium, tend to form ionic organometallic compounds. These compounds have limited use in synthesis. One example of using a different organometallic in a synthesis is... 

Ionic organic compounds involving carbanions react readily with oxygen. For example, ethyl-sodium, C2Hj Na+, self-ignites in air. Ionic organometallic compounds are extremely reactive in water, as shown by the following reaction ... 

Although a great deal of excitement has surrounded the use of ionic liquids as solvents for organic synthesis, the rational synthesis of inorganic and organometallic compounds in ionic liquids has remained largely unexplored. 

Organometallic compounds that are not ionic but polar-covalent behave very much as if they were ionic and give similar reactions. 

Activation energies have been studied in the case of solid ionic compounds, where the target compounds and their side products are somewhat more stable and easier to handle. No measurements of activation energies have as yet been made on organometallic compounds, and unfortunately, very few annealing studies have been done. 

The linear relationship given in Eq. (21) between log/ and l/T has been observed in ionic compounds with K2Cr04 (55) and KIO3 (17), but not yet with organometallic compounds. The work of Zahn et al. (99) suggests that such a relationship may exist, but the data are too few as yet. 

In organometallic compounds of the form RR R"C—M, pretty well the whole spectrum of bonding is known from the essentially covalent, via the polar-covalent, RR R"C, —M4+, to the essentially ionic, RR R"CeM . In their reactions, predominant retention, racemisation, and inversion of configuration have all been observed the outcome in a particular case depending not only on the alkyl residue, but also on the metal, and particularly on the solvent. Even with the most ionic examples it seems unlikely that we are dealing with a simple carbanion thus in the reaction of EtI with [PhCOCHMe]6 M , the relative rates under analogous conditions are found to differ over a range of 104 for M = Li, Na and K. 

The reactivity of organometallic compounds increases with the percent ionic character of the C-M bond. 

Room-temperature ionic liquids exhibit many properties that make them potentially attractive as solvents for catalysis [11]. They dissolve a wide range of organic, inorganic and organometallic compounds as well as gases, e.g., CO2, HCl, NH3, and to a much lower extent also H2 and CO. Many ionic liquids show temperature operating ranges of more than 300 °C compared... 

Nowadays we look with other eyes at organometallic compounds the family of which has expanded enormously. Some members of this family are soluble in water due to their ionic nature the legions of anionic carbonylmetallates (e.g. [Ni(CN)(CO)3] ) and cationic bisphosphine Rh-chelate complexes (e.g. [Rh(BDPP)(COD)] ) just come to mind. Others obtain their solubility in water from the well soluble ligands they contain these can be ionic (sulfonate, carboxylate, phosphonate, ammonium, phosphonium etc. derivatives) or neutral, such as the ligands with polyoxyethylene chains or with a modified urotropin structure. 

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