THE REACTION OF IRON PENTACARBONYL WITH 6-AMINOFULVENES - SOME ORGANIC-CHEMISTRY OF R,S AND R,R R,S-[FE-2(ETA,ETA-C5H4CH(NME(2))CH(NME(2))C5H4)(CO)(2)(MU-CO)(2)]

Iron pentacarbonyl reacts with 6-dimethylaminofulvene in refluxing xylene to give three products, 1, 2 and 3. Compound 1 is R,S-[Fe-2{eta eta-C5H4CH(NMe(2))CH(NMe(2))C5H4}(CO)(2)(mu CO)(2)],2 is its R,R S,S isomer, and 3 is [Fe-2(eta(3) eta(5)-Me(2)NCHC(5)H(3)CH- C5H4)(CO)(5)]. Compound 3 is favoured by high reactant concentrations and an excess of [Fe(CO)(5)]. Analogues of 2 and 3 but not 1 may be prepared by using 6-Me(Ph)NCHC5H4, 6-Et(2)NCHC(5)H(4) and 6-(Pr2NCHC5H4)-Pr-i; the last of these also gives the unlinked dimer [Fe{eta(5)-(C5H4CH2NPr2)-Pr-i}(2)(CO)(2)(mu-CO)(2)]. This behaviour is attributed to the steric effects of the NR(2) groups on the formation of the ring-linking C-C bond. Dynamic NMR studies show that in 1, but not 2, there is a slowable restricted rotation about this bond and, in both 1 and 2, rotation-inversion about the nitrogen atoms of the NMe(2) groups can be slowed. Compounds 1 and 2 are derivatives of a 1,2-bis-dimethylaminoethane, and as such have an extensive organic chemistry that leaves the Fe-2(CO)(2)(mu-CO)(2) moieties intact. There are differences between 1 and 2, due to conventional stereochemical effects, and consequently the Fe-2(CO)(2)(mu-CO)(2) fragments are involved in some instances; this leads to unexpected and unusual reactions. The structures of 2 and the ketone [Fe-2{eta,eta-C5H4CH2C(O)C5H4}(CO)(2)(mu-CO)(2)] have been confirmed by X-ray diffraction studies and are compared with that previously reported for 1.