Methyl-metal compounds Group

Tin is shown to be methylated by organisms and other environmental factors. Organic tin compounds are much more toxic than the inorganic ones. This increase in toxicity due, e.g., to methylation is attributable to the increasing membrane permeability of the methylated metal compounds and to the remaining sensibility to react with sulfhydryl groups of proteins, especially of enzyme proteins. 

Aluminum alkyls undergo many reactions that are typical of covalent metal compounds. Compounds containing methyl, ethyl, and propyl groups ignite spontaneously in air. The reactions with water take place with explosive violence when the alkyl groups contain four or fewer carbon atoms. 

C-13 nmr spectra were taken of all the alkali metal compounds of I and II from Li to Cs. As expected, changing the counter-ion had very little effect on the chemical shifts of the carbons in the neopentyl group in either I or II, or on the extra methyl group in II, compared with the parent hydrocarbon ( 3). 

However, in the final analysis, the fundamental limitation of the technique described above is that it is yet to be demonstrated that more than two CF3 groups can be affixed to any transition metal center by means of thermal decarbonylation-methyl migration reactions. Thus this procedure is extremely useful for the synthesis of certain categories of trifluoromethyl transition metal compounds, provided that only one or at most two CF3 groups are desired, but it cannot be regarded as a generally applicable synthetic method. 

For copper the 3d orbitals can be expected to make less than their full contribution to metal-ligand bonding as in other main group transition metal compounds (57). This is suggested by the infrared spectra of cyclopentadienylcopper complexes with methyl isocyanide or carbon... 

Organoalkali metal compounds of the heavier alkah metals with more highly substituted alkyl groups can be formed from the reaction of an alkane with the appropriate methyl derivative (MMe M = Na, K, Rb, and Cs ) (equation 18). 

A method of producing the sol is to hydrolyse reactive metal compounds, for example alkoxidcs, M(OR) , where M is a metal (e.g. Ce and other rare earths, Al, Ti, Zr, etc.) and R is an alkyl group (e.g. methyl, CH3, ethyl, C2H3, or propyl,... 

A common misconception is that carbon can, at most, be four-coordinate. Although carbon is bonded to four or fewer atoms in the vast majority of its compounds, many examples are now known in which carbon has coordination numbers of 5, 6, or higher. Five-coordinate carbon is actually rather common, with methyl and other groups frequently forming bridges between two metal atoms, as in Al2(CH3)g (see Figure 8-15). There is even considerable evidence for the five-coordinate ion Many organometallic cluster... 

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