_P.-Powell-auth.-Principles-of-Organometallic-Chemistry-Springer-Netherlands-1988

Five electron ligands
n-system of each ligand interacts with the second molybdenum atom as
illustrated.
9.3.3 CpFe(C0) 2 (1[ 1 -C 5 H 5 ): Fluxional behaviour
When CpFe(C0) 2 Br is treated with sodium cyclopentadienide, a complex is formed
in which two cyclopentadienyl groups are present:
NaCp
The proton n.m.r. spectrum, measured at ambient temperature, consists only of
two sharp signals of equal intensity (Fig. 9.14). The infrared spectrum. however,
+30
1
u
-19
• -25
~ /"'\.
;!. -40 __...- '-
~ -52 ~
E'-56 ~
::.-60 ~
-64 ~}\Ă
-80\
-100/
1
iÎ 6·5
1
6·0
1 """' 1 1
5·5 4·4 4·0
A
1
3·5
1
3·0
Fig. 9.14 The 'H n.m.r. spectra at 60 MHz of CpFe(C0) 2 (1J'-C,H,) in CS 2 at various
300
temperatures. The signal for the Cp protons is shown only on the 30oC
spectrum, the amplitude ofwhich is 0.1 times that ofthe others. (Reproduced by
permission from M.J. Bennett, F.A. Cotton, A. Davison, J.W. Palier, S.J. Lippard
and S.M. Morehouse, ]. Am. Chem. Soc., 1966, 88, 4371.)