I. Synthesis and Characterization of the New Cyclopentadienyl Vanadium Tricarbonyl Hydride and Methyl Anions and their Reactions with Organic Substrates. II. Monomeric Organometallic Dianions

The new anionic cyclopentadienyl vanadium tricarbonyl complexes, (n5C5H5)V(CO)3R-, (R=H,CH3),have been isolated as the phosphineminium salts. (n5C5H5)V(CO)3H- reacts with alkyl (primary, secondary, and tertiary), vinyl and aryl bromides at room temperature in THF to replace bromine with hydrogen. A gem-dibromocyclopropane was reduced to the mono-bromide, and acid chlorides were converted to aldehydes with (n5C5H5)V(CO)3H-. Primary alkyl iodides react more rapidly than the bromides and aklyl chlorides do not react at all. Alkyl tosylates react much slower than the corresponding bromides. Carbon radicals and (n5C5H5)V(CO)3Br- as the kinetic organometallic product imply a radical chain mechanism for these reactions. The reactions of (n5C5H5)V(CO)3CH-3 and alkylbromides and acyl chlorides do not produce new carbon-carbon bonds . Attempts to prepare the dianious RM(CO)2-3, M = Cr, Mo; R = norbornadiene and M = Mo; R = cyclooctatetraene were not successful.