New developments in the organometallic chemistry of the group IV-VII transition metals
The homogeneous activation of carbon—hydrogen bonds by tungstenocene and the observation of reversible 1,2—hydrogen shifts in tungstenocene derivatives has led to a widening study of tungstenocene—related chemistry. Many new compounds are described which were designed as tungstenocene precursor analogues and their ability to undergo thermally or photgchemically induced C—H activation has been explored. Simple d titanium—alkyls are described in which C—H groups of the alkyl ligand form covalent, three—centered two—electron Ti—H—C bonds. The activation of ethane is described for the first time. Arene—alkylidene—rhenium derivatives are formed nd it appears that the reaction is general for many alkanes and sp groups.