Niobium complexes acetylene

In a similar manner, UV irradiation of (triphenylsilyl)phenylacetylene with cyclopentadienylmanganese tricarbonyl 121) and cyclopentadienyl-niobium tetracarbonyl 122) results in elimination of carbon monoxide and formation of monodentate acetylene complexes (R = Ph) ... 

Complexes with acetylenes. This niobium(III) reagent readily forms complexes, (2a) and (2b), with acetylenes. When R and R are different, the bulkier alkyl group is oriented preferentially toward the hydride ligand. Treatment of the complexes (2) with acid yields, nearly quantitatively, the corresponding... 

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