Reactions of Cp(CO)/sub 2/Fe(C(XR)YR)/sup +/ where Cp = eta/sup 5/-C/sub 5/H/sub 5/ with amines occur at the carbene ligand when X, Y = O, S, and/or Se and the product distribution is dependent upon the leaving-group abilities of the carbene substituents (PhSe-approx. = PhS/sup -/, PhO/sup -/ > CH/sub 3/S/sup -/ > CH/sub 3/O). When both carbene substituents are good leaving groups (PhSe/sup -/, PhS/sup -/, PhO/sup -/, or CH/sub 3/S/sup -/), Cp(CO)/sub 2/Fe(C(XR)YR)/sup +/ reacts with primary amines to give isocyanide complexes, Cp(CO)/sub 2/FeCNR/sup +/, and with secondary amines to form carbene derivatives, Cp(CO)/sub 2/Fe(C(XR)NR/sub 2/)/sup +/. When only one carbene substituent is a good leaving group, Cp(CO)/sub 2/Fe(C(XR)YR)/sup +/ yields carbene derivatives, Cp(CO)/sub 2/Fe/sup +/(C(XR)NRR')/sup +/(XR = OCH/sub 3/; R' = R, H), upon reaction with primary or secondary amines. Substituents are poor leaving groups (CH/sub 3/O/sup -/), a complex mixture of products generally results on reaction with amines. A mechanism involving formation of an ylide intermediate, Cp(CO)/sub 2/Fe(C(XR)(YR)NR/sub 3/)/sup +/, is proposed to account for these results. Spectroscopic studies (ir and /sup 13/C NMR) show that N ..-->.. C (carbene) ..pi.. donation increases as the basicity of the amine group increases for the Cp(CO)/sub 2/Fe(C(OCH/sub 3/)NR/sub 2/)/supmore » +/ complexes.« less