The addition of small molecules to (.eta.-C5H5)2Rh2(CO)(CF3C2CF3). 3. The formation of a bridging acrylamide ligand on a dirhodium center by the cycloaddition of nitrenes, carbon monoxide, and an alkyne. X-ray crystal structure of (.eta.-C5H5)2Rh2[.mu.-.eta.3C(CF3)C(CF3)C(O)N(Ph)]