ISOCYANIDE-BRIDGED AND HETEROALLENE-BRIDGED METAL-COMPLEXES .9. DIIRON AND TRIIRON COMPLEXES WITH FUNCTIONAL BRIDGING ISOCYANIDES

The reactions of ten mainly functional isocyanide dichlorides RN=CCl2 with Na[FeCp(CO)2] in tetrahydrofuran give monoisocyanide derivatives [Fe2(CP)2(CO)3CNR] (1a-g) of [Fe-CP(CO)2]2 in which the isocyanide occupies a bridging position. In three cases also minor amounts of diisocyanide complexes [FeCp(mu-CNR)CO]2 (2c, 2e, 8) have been isolated. The chlorocarbonyl-substituted aryl isocyanide dichlorides and pentafluorophenyl isocyanide dichloride in addition suffer (CO)Cl/and F/metal exchange, respectively, with formation of mu-3-isocyanide-bridged triiron complexes (4a-c, 7) via the intermediates 5 and 6. 7 has been studied by X-ray analysis.