Studies on some substituted methyl derivatives of iron, molybdenum, and tungsten
The methoxymethyl complexes M–CH2·OMe, where M =π-C5H5Fe(CO)2 or π-C5H5(Mo or W)(CO)3, have been prepared. It is shown that a methoxy-group is readily cleaved from the system by acids. Hydrogen chloride forms the chloromethyl complexes M–CH2Cl which react readily with hydroxy-compounds ROH, forming the ether derivatives M–CH2OR. Cleavage of the iron methoxymethyl complex with the acids H+A–, where A = ClO4, PF6, or BF4, gives a mixture of products which include the ethylene complex [π-C5H5Fe(CO)2C2H4]+A–. It is suggested that carbene intermediates are involved in these reactions. The chemical shifts of the methylene hydrogens in some complexes π-C5H5Fe(CO)2CH2R are discussed.