From complex transition metal anions and halides

From complex transition metal anions and halides 

Complexes which contain a transition metal in the anion may react with alkyl halides to yield 7-alkyl metal derivatives. Such anions are formed commonly by reduction of metal carbonyls or cyclopentadienyl metal carbonyls with sodium amalgam in tetrahydrofuran  

With allyl halides a 7-aUyl derivative is first formed, which may be converted, by loss of one carbonyl or cyanide group, into ir-allyl derivatives, either by heating or by ultraviolet irradiation  

Similarly benzyl chloride reacts with Na [ir-C5H5Mo(CO)3] to form the expected r-benzyl derivative ir-CjH5Mo(CO)3 r-CH2Ph. On irradiation, carbon monoxide is evolved, and a red compound is formed, which has been shown to be the first example of a complex containing the 3-electron w-benzyl system 6.6  

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