8/12/2019 ORGANOMETALLIC TUROTIAL
1/2
1
ORGANOMETALLIC CHEMISTRY
1.Write a mechanism for the conversion of allyl alcohol
(CH2=CH-CH2OH) to propanal
using HCo(CO)4as catalyst.
2. The following compounds are known: (C7H
7)Cr(C
5H
5), (C
6H
6)Mn(C
5H
5), (C
5H
5)2Fe,
(C4H4)Co(C5H5). Suppose you wish to make a compound which
contained both a
cyclopentadienyl ring and a three-membered ring, show how you
might attempt to
synthesise such a compound.
3. Predict reasonable product(s) for the following
reactions:
(i) Nb(CH2CMe3)4Cl + 2PMe3 A + B
(ii) (Me3CCH2)3TaCl2 + 2Me3CCH2LiC
(iii) W(CO)6 + LiMe D
(iv) D + Me3O+ E
4. (a) Suggest a plausible mechanism for the following
reaction:
RhH(CO)(PPh3)3+ C2H4+ PhCOCl ----> PhCOC2H5+ RhCl(CO)(PPh3)2
+ PPh3
5. Identify compounds Ato Dand briefly comment on the
reactions.
Na[(5-C5H5)W(CO)3]+ CH2= CH - CH2Cl A
NaBH4
HPF6
h D
CB
B: %W = 35.4; %C = 25.4; %P = 5.96
Mass spectrum M+(based on 184W): C= 376; D = 346
[C = 12, P = 31, H = 1, Na = 23, F = 19, B = 11, O = 16, Cl =
35.5]
6.Show how a hydrido species can cause isomerisation of
hex-1-ene to cis and trans hex-
2-enes.
7.The complex [RhCl(PPh3)3] is well-known as a catalyst for the
alkene hydrogenation.
Present a catalytic cycle for this process.
Although useful for a wide range of alkenes, the presence of an
aldehyde functionality in
the alkene can cause loss of activity. Account for this
observation.
This complex has been shown to catalyse an isomerisation of
4-pentenals. The fate of
the majority of the deuterium label in the aldehyde hydrogen
site is shown below:
8/12/2019 ORGANOMETALLIC TUROTIAL
2/2
2
O
DD
O
In the light of the reactions you have discussed above, suggest
a catalytic cycle for this
isomerisation.
8. Give a method of synthesis for each of the following
compounds, specifying the
chemical(s) used and nature of reaction(s) involved. (Starting
material given in
parentheses)
(i) Ferrocene (C5H6)
(ii) Aminoferrocene (ferrocene)
(iii)
C
CH3
OCH3
(CO)5W
(W(CO)6)
(iv)
CH2
CH3
(C5H5)2Ta
[(C5H5)2Ta(CH3)3]
(v)
O O
H3C
H3C
Fe(CO)3
CH3
CH3
[Fe(CO)5]
(vi)
Br
[Cp2ZrHCl]
(vii) (C5H5)Mn(C6H6) [(C5H5)MnCl](viii) [(5-C5H5)Fe(CO)2(C2H4)]+
from [(5-C5H5)Fe(CO)2]2(ix) [(5-C5H5)Ni(-C5H5)Ni(5-C5H5)]+from
NiCl2
