B. Callan et al., THE REACTION OF IRON PENTACARBONYL WITH 6-AMINOFULVENES - SOME ORGANIC-CHEMISTRY OF R,S AND R,R A-C5H4CH(NME(2))CH(NME(2))C5H4)(CO)(2)(MU-CO)(2)]/, Journal of organometallic chemistry, 466(1-2), 1994, pp. 185-199
Iron pentacarbonyl reacts with 6-dimethylaminofulvene in refluxing xyl
ene to give three products, 1, 2 and 3. Compound 1 is R,S-[Fe-2{eta et
a-C5H4CH(NMe(2))CH(NMe(2))C5H4}(CO)(2)(mu CO)(2)],2 is its R,R/S,S iso
mer, and 3 is [Fe-2(eta(3) eta(5)-Me(2)NCHC(5)H(3)CH- C5H4)(CO)(5)]. C
ompound 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 e{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. Dy
namic NMR studies show that in 1, but not 2, there is a slowable restr
icted rotation about this bond and, in both 1 and 2, rotation-inversio
n about the nitrogen atoms of the NMe(2) groups can be slowed. Compoun
ds 1 and 2 are derivatives of a 1,2-bis-dimethylaminoethane, and as su
ch 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 unex
pected 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-r
ay diffraction studies and are compared with that previously reported
for 1.