Hydrides hexacarbonyl derivatives

Vanadium hexacarbonyl reacts with various arenes yielding complexes [(arene)V(CO)4]" [V(CO)6] from which hexafluorphosphate or tetra-phenylborate salts can be prepared by metathesis reaction (50, 52). The cation [(CeHe)V(CO)4] reacts with NaBH4 to give the neutral cyclo-hexadienyl compound (CeH7)V(CO)4 (51). Similar results are observed with methyl-substituted derivatives. The addition of the hydride ion was shown to occur preferentially at unsubstituted positions of the aromatic ring. 

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