Protonation and acylation of the heterometallic complexes (μ-H)Os3(μ-O2CC5H4FeCp)(CO)10 and Fe{(μ-O2CC5H4)(μ-H)Os3(CO)10}2

Article abstract of DOI:10.1023/A:1015064419785

The reactions of the heterometallic complexes (μ-H)Os₃(μ-O₂CC₅H₄FeCp)(CO)₁₀ (1) and Fe{(μ-O₂CC₅H₄)(μ-H)Os₃(CO)₁₀}₂ (2) with CF₃COOH, CF₃SO₃H, and AcCI were studied. The reaction of 1 with CF₃COOH involves interaction with the Cp ligands, protonation of the O atom of the bridging carboxylate group, and oxidative degradation of the complex. At low concentrations, CF₃SO₃H protonates the O atom of the bridging carboxylate group, while at high concentrations, degradation of the complex takes place. The reaction of complex 2 with either CF₃COOH or low concentrations of CF₃SO₃H results in successive elimination of two [(μ-H)Os₃(CO)₁₀] cluster fragments due to protonation of the O atoms of the carboxylate groups. In the case of high CF₃SO₃H concentrations, the Os-Os bonds of both cluster fragments of 2 are also protonated to give the [Fe{(μ-O₂CC₅H₄)(μ-H)₂Os₃(CO)₁₀}₂]²⁺ dication. The Friedel-Crafts acylation of 1 takes place only when a large excess of AcCl and AlCl₃ is used to give two new complexes, (μ-H)Os₃(μ-O₂CC₅H₄FeC₅H₄C(O)CH₃)(CO)₁₀ and (μ-H)Os₃(μ-O₂CC₅H₃C(O)CH₃ FeCp)(CO)₁₀ in a 2 : 1 ratio.

Full text of DOI:10.1023/A:1015064419785

Russian Chemical Bulletin, International Edition, Vol. 50, No. 12, pp. 2451—2458, December, 2001
2451
Protonation and acylation of the heterometallic complexes
(µ-H)Os3(µ-O2CC5H4FeCp)(CO)10 and
Fe{(µ-O2CC5H4)(µ-H)Os3(CO)10}2
V. A. Maksakov,à« I. V. Slovohotova,à A. V. Golovin,b and S. P. Babailovà
àInstitute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences,
3 prosp. Akad. Lavrentyeva, 630090 Novosibirsk, Russian Federation.
Fax: +7 (383 2) 34 4489. E-mail: maksakov@che.nsk.su
bNovosibirsk State University,
2 ul. Pirogova, 630090 Novosibirsk, Russian Federation
The reactions of the heterometallic complexes (µ-H)Os3(µ-O2CC5H4FeCp)(CO)10 (1)
and Fe{(µ-O2CC5H4)(µ-H)Os3(CO)10}2 (2) with CF3COOH, CF3SO3H, and AcCl were
studied. The reaction of 1 with CF3COOH involves interaction with the Cp ligands,
protonation of the O atom of the bridging carboxylate group, and oxidative degradation of
the complex. At low concentrations, CF3SO3H protonates the O atom of the bridging
carboxylate group, while at high concentrations, degradation of the complex takes place. The
reaction of complex 2 with either CF3COOH or low concentrations of CF3SO3H results in
successive elimination of two [(µ-H)Os3(CO)10] cluster fragments due to protonation of
the O atoms of the carboxylate groups. In the case of high CF3SO3H concen-
trations, the Os—Os bonds of both cluster fragments of 2 are also protonated
to give the [Fe{(µ-O2CC5H4)(µ-H)2Os3(CO)10}2]2+ dication. The Friedel—Crafts
acylation of 1 takes place only when a large excess of AcCl and AlCl3 is
used to give two new complexes, (µ-H)Os3(µ-O2CC5H4FeC5H4C(O)CH3)(CO)10 and
(µ-H)Os3(µ-O2CC5H3C(O)CH3FeCp)(CO)10 in a 2 : 1 ratio.
Key words: osmium and iron heterometallic complexes, protonation, acylation, 1H NMR
spectroscopy.
A large number of studies published in recent years
have been devoted to the synthesis of heterometallic
complexes in which either a cluster fragment and a
mononuclear fragment or several cluster fragments are
linked by polyfunctional ligands.1—4 For many com-
pounds of this type, chemical properties of the constitu-
ent metal complexes have been studied fairly compre-
hensively. It appears pertinent and important to study
the influence of metal fragments in these complexes on
their reactivities.
Previously, we have prepared several heterometallic
complexes containing anilinechromiumtricarbonyl,5
cymantrenecarboxylic,6 ferrocenecarboxylic, and ferro-
cenedicarboxylic acids7 as ligands in triosmium carbonyl
clusters. The last-mentioned case was represented by
three complexes in which the ferrocenyl fragment is
linked to either one ((µ-H)Os3(µ-O2CC5H4FeCp)(CO)10
(1) and (µ-H)Os3(µ-O2CC5H4FeC5H4COOH)(CO)10) or
two (Fe{(µ-O2CC5H4)(µ-H)Os3(CO)10}2 (2)) triosmium
clusters. Later, more detailed procedures for the synthe-
sis of complexes 1 and 2 have been published and the
electrochemical properties of these complexes have been
studied.8 Here we describe the behavior of complexes 1
and 2 in reactions with electrophilic reagents, namely,
protonation and Friedel—Crafts acylation.
Compounds 1 and 2 can be protonated at the Fe
atom, the Os3 ring, or the Cp ligands. The protonation
of the O atoms of the bridging carboxylate groups also
cannot be ruled out, although their basicities are ex-
pected to decrease upon the coordination to the cluster.
The protonation site in ferrocene and its derivatives
depends on the strength of the acid used and the nature
of substituents in the Cp ligands. Weak and medium-
strength acids react with cyclopentadienyl ligands9,10
and strong acids protonate the Fe atom.11 When oxy-
gen-containing functional groups (aldehyde,12 acyl,13 or
hydroxy14 groups) are introduced in the Cp ring of
ferrocene, the protonation site shifts to the O atom.
Superacids protonate acylferrocenes at both O and Fe
atoms.15 The triosmium (µ-H)Os3(µ-X)(CO)10 clusters
are protonated at the Os—Os bond.16,17 The protonation
site can move from the Os3 metal ring to the ligands16—19
if the ligands contain, for example, a lone electron pair
or a multiple bond. Data on the protonation of the
heterometallic (µ-H)Os3(µ-O=CC5Ìå4MC5Me5)(CO)10
complexes (M = Fe, Ru, Os) in which the metallocenyl
fragments are coordinated by a bridging aldehyde
group are documented.20 In a HBF4/CF3COOH mix-
ture, these complexes are protonated at the metal
atom of the metallocenyl fragment. The protonated
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2340—2347, December, 2001.
1066-5285/01/5012-2451 $25.00 © 2001 Plenum Publishing Corporation

2452
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 12, December, 2001
Maksakov et al.
[(µ-H)Os3(µ-O=CC5Me4FeHC5Me5)(CO)10]+ complex,
unlike the other two complexes, is unstable and is
rapidly converted into the ferrocenium derivative exhib-
iting paramagnetic properties.20
Results and Discussion
Complexes 1 and 2 were protonated by CF3COOH
and CF3SO3H. The addition of 2 equiv. of CF3COOH
1
2
3
4
5
7
6
5
4
–10
–12
δ
Fig. 1. Changes in the 1H NMR spectra (250 ÌHz, CDCl3) of a solution of the (µ-H)Os3(µ-O2CC5H4FeCp)(CO)10 complex (1)
in CDCl3 in the presence of 2 equiv. of CF3COOH: spectra 1—3 were recorded at 3-h intervals, spectrum 4 was measured 18 h
after the onset of the reaction, and spectrum 5 was recorded after 2 days.

Protonation and acylation of Os3Fc complexes
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 12, December, 2001 2453
Scheme 1
to a solution of (µ-H)Os3(µ-O2CC5H4FeCp)(CO)10 (1)
1
in CD2Cl2 or CDCl3 induces broadening of H NMR
signals and downfield shifts of the signals of the Cp
protons and upfield shifts of the µ-H signals (Fig. 1).
The signals of Cp protons gradually approach each other
and finally coalesce at about δ 5.5. After about 2 days,
broadened signals typical of the Cp protons of a mono-
substituted ferrocene appear again in the region of δ 4.5;
they shift downfield and approach each other with time
as described above. In the high-field region, a narrow,
intense signal appears (δ –10.3), whose position remains
unchanged, and several other weak signals. As the reac-
tion progresses, the color intensity of the solution de-
creases and a dark solid precipitates. Chromatographic
separation of the reaction mixture (elution with
hexane—benzene—acetone, 4 : 2 : 1.5) gave the
known16 (µ-H)Os3(µ-O2CCF3)(CO)10 cluster (3) (30%),
which is responsible for a signal with δ –10.30, the
(µ-H)Os3(µ-Cl)(CO)10 complex21 (1 to 3% in various
experiments), responsible for the µ-H signal with
δ –14.25, and ferrocenecarboxylic acid (up to 30%),
(CO)3
O Os
Os(CO)4
H
CF3COOH
O Os
(CO)3
Fe
CDCl3
1
Os(CO)4
H
COOH
(CO)3Os
O
Os(CO)3
Fe
+
O
CF3
3
reaction is an order of magnitude faster. Twenty minutes
after the introduction of 1.5 equiv. of CF3SO3H into a
solution of complex 1 in CDCl3, two broad signals
(δ 5.18 and 4.77) in a 2 : 7 ratio of integrated intensities
and a somewhat broadened high-field singlet with
δ –10.14 appear in the 1H NMR spectrum of the
reaction mixture; this virtually reproduces the spectrum
shown in Fig. 1, spectrum (3). The pattern of subse-
1
which was identified from IR and H NMR spectra.22
As the CF3COOH concentration increases threefold, all
the protons of the Cp ligands in complex 1 appear in the
spectrum as a single broad signal. With a 20-fold excess
of the acid with respect to complex 1, no signals for the
Cp protons are observed in the spectrum; apparently,
they merge with the intense signal of the CF3COOH
protons. An increase in the concentration of the acid
markedly accelerates the process.
Analysis of the spectrocopic data indicates that the
reaction of complex 1 with CF3COOH follows two
pathways: the acid either reacts with the Cp ligands or
protonates the O atom of the carboxylate group. In the
former case, the signals for the Cp protons are broad-
ened. The gradual downfield displacement and the sub-
sequent broadening of these signals is apparently due to
the oxidative processes that usually take place in
CF3COOH-containing solutions of ferrocene derivatives
in air.23 This results in partial decomposition of the
complex. Protonation of the O atoms of the bridging
ligand is accompanied by substitution of a trifluoroacetate
group for the ferrocenecarboxylate ligand in complex 1
and gives rise to (µ-H)Os3(µ-O2CCF3)(CO)10 (3) and
ferrocenecarboxylic acid, which is also oxidized under
the reaction conditions (Scheme 1).
The reaction of CF3COOH with the [Os3(CO)10]
fragment arising upon decomposition of complex 1 rep-
resents an alternative route to cluster 3. It was shown in
a special experiment that in the presence of CF3COOH,
the acetate group in (µ-H)Os3(µ-O2CCH3)(CO)10 is
replaced by a trifluoroacetate group. Neither in this
reaction nor in the reaction of CF3COOH with com-
plex 1, the protonation of the Os—Os bond takes place,
which indicates a lower basicity of the Os3 metal ring
compared to the O atoms of the carboxylate ligands.
The reaction of complex 1 with CF3SO3H is similar
to that described above except for two points. First, this
1
quent changes in the H NMR spectra of the reaction
mixture recorded at 20—30 min intervals is close to that
of the corresponding spectra shown in Fig. 1. About 1 h
after the beginning of the reaction, the solution starts to
darken and after 2.5—3 h, a dark precipitate appears.
After 7—9 h (the signals of complex 1 disappear from
the 1H NMR spectra), only a small amount (6—9%) of
ferrocenecarboxylic acid can be isolated from the reac-
tion mixture; probably, the bulk of the acid decomposes
upon oxidation. The decomposition of complex 1 is
–
apparently due to the fact that the CF3SO3 anion
cannot stabilize efficiently the [HOs3(CO)10] fragment
formed in the first stage of the reaction. With a 6-fold
excess of CF3SO3H, a vigorous reaction takes place
accompanied by gas evolution and precipitation of a
1
dark solid. The H NMR spectrum of the reaction
mixture recorded 10 min after the onset of the reaction
exhibits two broad signals in the region of δ 4.5 and a
weak singlet with δ –19.42, which then rapidly disap-
pears. Only traces of ferrocenecarboxylic acid can be
detected in the reaction mixture (TLC).
The Fe{(µ-O2CC5H4)(µ-H)Os3(CO)10}2 complex
(2) contains an additional electron-withdrawing
[(µ-CO2)(µ-H)Os3(CO)10] cluster group as compared to
complex 1. This decreases the basicity of the ferrocenyl
fragment, which appreciably affects the ability of this
complex to react with electrophilic reagents. Only with a
40-fold excess of CF3COOH, do signs of the reactions
appear. Within 24 h after beginning of the reaction, new
multiplet signals corresponding in structure to the pro-

2454
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 12, December, 2001
Maksakov et al.
1
2
3
5.0
4.8
4.6
4.4
–10.2
δ
1
Fig. 2. Changes in the H NMR spectra (250 ÌHz) of a solution of the Fe{(µ-O2CC5H4)(µ-H)Os3(CO)10}2 complex (2) in
CD2Cl2 in the presence of a 40-fold excess of CF3COOH: initial spectrum (1), spectra recorded within 1 day (2) and 6 days (3)
after the onset of the reaction.
ton signals of substituted Cp ligands appear at about
δ 4.5 in the 1H NMR spectrum of the reaction mixture
(Fig. 2). Simultaneously, two signals of the hydride H
atoms appear in the high field; their chemical shifts
differ from each other and from that of the µ-H signal of
complex 2 only by several Hz. The intensity of two
other, barely visible analogous multiplet signals gradu-
ally increases and after 2 days it reaches the intensity of
other signals (see Fig. 2, spectrum 3). The reaction
proceeds slowly; after 10 days, the reaction mixture
contains ∼40% of the initial complex 2 and ∼30% of
each of the newly formed compounds with Cp ligands
entails the appearance of one more pair of multiplet
signals in the low field in the H NMR spectrum.
1
Chromatographic separation of the reaction mixture on
Silufol plates results in slight amounts of complexes 2,
3, and 4 and ferrocenedicarboxylic acid, which is con-
sistent with the proposed reaction scheme. The structure
of complex 4 was confirmed by its independent syn-
thesis.
The pathway of the reaction of CF3SO3H with com-
plex 2 depends on the ratio of the reactant concen-
trations. When the CF3SO3H concentration is low
(2 : CF3SO3H = 3 : 1), the first step of the reaction
involves elimination of one cluster fragment to give the
(µ-H)Os3(µ-O2CC5H4FeC5H4COOH)(CO)10 (4) com-
plex. The chemical shifts of protons of complex 4 in the
1H NMR spectrum of the reaction mixture (CDCl3, δ:
4.98, 4.84, 4.69, 4.52 (all m, 2 H each, CH); –10.24 (s,
1 H, µ-H)) differ substantially from the chemical shifts
of signals in the spectrum of pure complex 4 recorded in
acetone (see Experimental). However, if the IR and
1H NMR spectra of this complex isolated from the
reaction mixture in a pure state and similar spectra of
complex 4 are recorded under the same conditions, they
1
(Scheme 2). The observed changes in the H NMR
spectrum of the reaction mixture are due to the succes-
sive elimination of two [HOs3(CO)10] fragments from
the initial complex. Upon the formation of complex 4,
two pairs of multiplets due to the protons of Cp ligands
containing different substituents and a new high-field
1
signal (δ –10.20) appear in the H NMR spectrum,
while the formation of cluster 3 gives rise to the µ-H
signal at δ –10.18. The second, slower step involves
elimination of the second hydridocarbonyl fragment from
complex 4. The formation of ferrocenedicarboxylic acid

Protonation and acylation of Os3Fc complexes
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 12, December, 2001 2455
Scheme 2
Os(CO)4
H
(CO)3Os
O
Os(CO)3
COOH
Os(CO)4
O
H
CF3COOH
CDCl3; 20 °C
(CO)3Os
O
Os(CO)3
O
(CO)3
O Os
Fe
Fe
+
Os(CO)4
H
CF3
O Os
(CO)3
O
O
3
(CO)3Os
Os(CO)3
H
4
CF3COOH
Os(CO)4
COOH
COOH
2
Fe
3
+
are virtually identical. The intensity of proton signals of
complex 4 in the H NMR spectrum of the reaction
vacuo with addition of acetone three times and the solid
residue was separated on Silufol plates. The initial com-
plex 2 was recovered in 60% yield probably due to its
parallel protonation at the O atoms of the carboxylate
ligands as shown in Scheme 2.
1
mixture reaches a maximum after 2.5 h and then gradu-
ally decreases. After 1.5 days, only signals of the initial
complex 4 remain in the spectrum. The [HOs3(CO)10]
cluster fragment, formed inevitably both in the first
(formation of complex 4) and second (reaction of com-
plex 4 with the acid) steps is apparently destroyed
because it cannot be stabilized efficiently under the
reaction conditions. Subsequently, CF3SO3H seems to
react mainly with complex 4, which results in the de-
struction of the complex. As a consequence, after 1.5 days
the 1H NMR spectrum of the reaction solution exhibits
mainly the proton signals of the initial complex 2 and
weak signals due to ferrocenedicarboxylic acid. The
reaction stops apparently after CF3SO3H has been com-
pletely exhausted.
When a 15-fold excess of CF3SO3H is added
to a solution of cluster 2 in CD2Cl2, both metal
cluster fragments are protonated to give the
[Fe{(µ-O2CC5H4)(µ-H)2Os3(CO)10}2]2+ dication. As a
consequence, the cyclopentadienyl protons in the
1H NMR spectrum shift downfield by ∼0.7 ppm and two
new, somewhat broadened singlets (δ –15.25 and –17.67)
appear in the high field. Broadening of the signals of the
hydride H atoms is due, most likely, to the intramolecu-
lar exchange between these atoms. The high-field re-
gion also contains a weak broadened multiplet with
δ –9.3 and a singlet with δ –14.25 (the signal of
(µ-H)Os3(µ-Cl)(CO)10), which disappear after 2 h. Sub-
sequently, no changes take place in the 1H NMR spec-
trum of the reaction mixture. Within 7 h after the onset
of the process, the reaction mixture was concentrated in
Among reactions of ferrocene and its derivatives with
electrophilic reagents, alkylation and acylation are as
characteristic as protonation. Acylation is performed
most often using acyl halides or carboxylic acid anhy-
drides and aluminum chloride as the catalyst.11 Acyla-
tion using these procedures mainly yields diketones hav-
ing heteroannular structures. Monoacylferrocenes are
formed when the reactants are taken in strictly equiva-
lent amounts. Electron-donating substituents in ferrocene
facilitate acylation of the substituted Cp ring, while in
the presence of electron-withdrawing substituents, e.g.,
the [—CO2Os3(µ-H)(CO)10] fragment, acylation involves
the unsubstituted ring.
For acylation of complex 1, we chose the proce-
dure24 proposed for the reactions of esters of ferrocene-
monocarboxylic acids with AcCl, because the electron-
withdrawing properties of the ester group appear to be
rather close to those of the [—CO2(µ-H)Os3(CO)10]
fragment in complex 1. When the 1 : AcCl : AlCl3 ratio
was 1 : 4 : 4, as in the published procedure,24 the
reaction did not proceed in CCl4. Acylation of complex
1 becomes possible only in the presence of a large
excess of AcCl and AlCl3. The optimal yields of the
acylation products (Scheme 3) were obtained with
1 : AcCl : AlCl3 ≈ 1 : 11 : 16.
The main reaction product was the (µ-H)Os3(µ-
Cl)(CO)10 cluster (∼30%), whose formation is associated
with the appearance of HCl in the reaction medium

2456
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 12, December, 2001
Maksakov et al.
Scheme 3
(CO)3
O Os
(CO)3
O Os
Os(CO)4
Os(CO)4
H
H
AcCl; AlCl3
O Os
O Os
Fe
Fe
+
(CO)3
(CO)3
–15 °C; CCl4
1
COMe
5
COMe
(CO)3
O Os
Os(CO)4
H
Os(CO)4
H
COOH
O Os
(CO)3Os
Os(CO)3
+
Fe
+
Fe
+
(CO)3
Cl
6
upon acylation of the initial complex. Hydrogen chlo-
ride protonates the O atoms of the carboxylate bridges of
both the initial complex and the acylation products,
resulting in elimination of [HOs3(CO)10] fragments,
ferrocenes containing an electron-withdrawing substitu-
ent in one Cp ligand.
Experimental data obtained in this work indicate that
the behavior of complexes 1 and 2 in an acidic medium
is mainly governed by the basicity of the O atoms of the
carboxylate groups and the electron-withdrawing prop-
erties of the [—CO2Os3(µ-H)(CO)10] cluster fragments.
The electron-withdrawing properties of the cluster frag-
ment determine also the conditions and the pattern of
the acylation of complex 1.
–
which then add the Cl ion. This process reduced
appreciably the yield of the major acylation products of
complex 1. Ferrocenecarboxylic acid formed in the re-
action is apparently protonated by HCl and forms a
complex with AlCl3, which is removed from the reac-
tion. In the separation of the reaction mixture on Silufol
plates, this complex remains at the application point and
decomposes partially only when some acetone is added
to the solvent system. The structures of acylated com-
plexes 5 and 6 can be judged reliably based on the IR
and NMR spectra. The four multiplet signals with equal
integrated intensities in the low-field region of the
1H NMR spectrum of complex 5 (Fig. 3) are typical of
1,1´-disubstituted ferrocenes whose substituents differ in
donor-acceptor properties.11 The signal of the Me group
of the acyl fragment has a typical chemical shift (δ 2.39).
A new band corresponding to stretching vibrations of the
Experimental
Acylation of complex 1 and synthesis of complex 4 were
carried out under Ar. The solvents were purified by standard
procedures and removed from reaction mixtures under reduced
pressure. Analytical chromatography was performed on Silufol
plates; preparative chromatography was performed on Silufol
plates and on a column with Silica gel 100/160. Complexes 1,7
2,7 Os(CO)11NCMe,26 and (µ-H)Os3(µ-O2CCH3)(CO)10
16
were prepared by known procedures. IR spectra were recorded
on a Specord IR-75 spectrometer, and H NMR spectra were
1
–1
acyl CO bond appears in the IR spectrum at 1681 cm ,
–1
registered on Bruker DPX-250 (250.13 MHz) and Tesla BS-567
(100 MHz) spectrometers using Me4Si as the internal standard.
Mass spectra (EI) were obtained on MKh-1310 (70 eV) and
Finnigan MAT 8200 (70 eV) spectrometers. The masses of
Os-containing compounds and fragments are given for the
192Os isotope, those for iron-containing compounds are given
for 56Fe.
Protonation of complexes 1, 2, and (µ-H)Os3(µ-
O2CMe)(CO)10 was performed in air. The course of reactions
of complexes 1 and 2 with acids was monitored by following
the changes in the 1H NMR spectra. For this purpose, a
known amount of the acid or a solution of the acid in a
deuterated solvent with a known concentration was introduced
in an NMR tube with solution of the complex in a CD2Cl2 or
CDCl3, and the 1H NMR spectra were recorded at definite
time intervals.
while the band at ∼1110 cm peculiar to unsubstituted
Cp rings of ferrocene25 is not recorded. In the IR
spectrum of complex 6, a similar band is observed at
–1
1108 cm . The low-field region of the 1H NMR spec-
trum of this complex is typical of 1,2-disubstituted
ferrocenes containing two electron-withdrawing groups.
Two lowest-field multiplets correspond to the H atoms
attached to carbon atoms closest to electron-withdraw-
ing groups. The third signal having a somewhat smaller
chemical shift is due to the remaining H atom. In
addition, the 1H NMR spectrum of complex 6 contains
the signals due to the protons of the unsubstituted Cp
ring, the acyl group, and the µ-H ligand. This ratio of
acylation products of complex 1 is usually observed for

Protonation and acylation of Os3Fc complexes
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 12, December, 2001 2457
IR (hexane), ν/cm–1: 2114 w, 2075 vs, 2063 s, 2027 vs, 2015 s,
2009 sh, 1987 m, 1984 sh, 1982 sh (CO); 1684 w (—C(O)Me);
1543 w (—CO2—), 1108 w (Cp). 1H NMR (250 ÌHz, CDCl3,),
δ: 4.73 (m, 1 H, C5H3); 4.68 (m, 1 H, C5H3); 4.44 (m, 1 H,
C5H3); 4.22 (m, 5 H, Cp); 2.35 (s, 3 H, MeCO—); –10.25 (s,
1 H, µ-H). The mass spectrum contained a molecular ion peak
[M]+ with m/z = 1128 (Irel ∼26%) and peaks with variable
intensities (16 to 100%) corresponding to abstraction of ten
CO groups from the cluster fragment;
(CO)3
O Os
Os(CO)4
H
O Os
(CO)3
Fe
1
—
1-{1,2-µ,η2-(O,O´)-carboxylato-(1,2-µ-hydrido)-
1,1,1,1,2,2,2,3,3,3-decacarbonyl-triàngulo-triosmium}-1´-
acetylferrocene (5) (21 mg, 22%), an orange crystalline solid.
IR (hexane), ν/cm–1, 2114 w, 2075 vs, 2064 s, 2028 vs,
2026 sh, 2017 s, 2014 sh, 2008 m, 1987 m, 1984 sh (CO);
1681 w (—C(O)Me); 1545 w (—CO2—). 1H NMR (250 ÌHz,
CDCl3,), δ: 4.73, 4.58, 4.44, 4.30 (all m, 2 H each, 2 CH);
2.39 (s, 3 H, —C(O)Me); –10.18 (s, 1 H, µ-H). The mass
spectrum contained a molecular ion peak [M]+ with m/z = 1128
(Irel ∼37%) and peaks with variable intensities (21 to 100%)
corresponding to the abstraction of ten CO groups from the
cluster fragment; and
1
MeCO
Fe
(CO)3
O Os
Os(CO)4
H
O Os
(CO)3
— a brick-orange solid (4 mg, 19%), whose IR spectrum
coincided with the spectrum of ferrocenecarboxylic acid.22
Reaction of the Fe{(µ-O2CC5H4)(µ-H)Os3(CO)10}2 com-
6
plex (2) with CF3SO3H. A solution (0.2 mL) of CF3SO3H
–6
(1 mg, 7•10
mol) in CD2Cl2 was added to a solution of
2
–5
complex 2 (82 mg, 4.2•10
mol) in 1 mL of CD2Cl2 and
1H NMR spectra of the reaction mixture were recorded every
20 min. After 2.5 h, the mixture was concentrated in vacuo and
separated on Silufol plates using a 1 : 1.5 hexane—ether
solvent system to give two major fractions. The first fraction
(CO)3
O Os
Os(CO)4
H
1
(38 mg, 46%) was complex 2 according to IR and H NMR
O Os
(CO)3
spectra.8 The second fraction (38 mg, 26%) was an orange-
Fe
1
brown solid, whose IR and H NMR spectra were virtually
5
identical with the corresponding spectra of complex 4. A trace
amount of ferrocene-1,1´-dicarboxylic acid, identified by chro-
matography, was also isolated.
OCMe
1-{1,2-µ,η2-(O,O´)-Carboxylato-(1,2-µ-hydrido)-
1,1,1,1,2,2,2,3,3,3-decacarbonyl-triàngulo-triosmium}-1´-
3
carboxyferrocene (4). A solution of Ìå3NO•2H2O (40 mg,
5.0
4.8
4.6
4.4
4.2
δ
–4
3.6•10
mol) in 4 mL of anhydrous MeOH was added
1
dropwise with stirring over a period of 1 h to a suspension of
Os(CO)11NCMe (135 mg, 1.7•10 mol) in 65 mL of MeCN.
Then the reaction mixture was passed through a column with
Silica gel, the Os(CO)10(NCMe)2 complex was eluted with
benzene, and the solvent was removed in vacuo. The solid
Fig. 3. Low-field region of the H NMR spectra (250 ÌHz,
CDCl3) of (µ-H)Os3(µ-O2CC5H4FeCp)(CO)10 (1) (1),
(µ-H)Os3{µ-O2CC5H3C(O)MeFeCp}(CO)10 (6) (2), and
(µ-H)Os3{µ-O2CC5H4FeC5H4C(O)Me}(CO)10 (5) (3).
–4
residue was dissolved in 35 mL of THF and ferrocene-1,1´-
–4
dicarboxylic acid (80 mg, 2.9•10
mol) was added. The
Reaction of the (µ-H)Os3(µ-O2CC5H4FeCp)(CO)10 com-
reaction mixture was refluxed for 1 h, the solvent was removed
in vacuo, and the solid residue was chromatographed on a
column with Silica gel 40/100 using a hexane—ether mixture
(1 : 1.5) as the eluent to give an orange-brown solid (17 mg,
3%) whose IR and 1H NMR spectra were similar to the
corresponding spectra of complex 2 7,8 and (µ-H)Os3(µ-
O2CC5H4FeC5H4COOH)(CO)10 (4), an orange-brown solid
(68 mg, 41%); IR (hexane), ν/cm–1: 2113 w, 2072 vs, 2062 s,
2027 vs, 2016 s, 2005 m, 1985 m, 1981 m (CO); 1686 w
plex (1) with AcCl. A solution of complex 1 (100 mg,
–5
9.2•10
mol) in 12 mL of CCl4 was added with vigorous
stirring and cooling to –15 °C over a period of 2 h to a
–3
suspension of AlCl3 (200 mg, 1.5•10 mol) and a solution of
–3
AcCl (80 mg, 1•10
mol) in 6 mL of CCl4. The reaction
mixture was warmed to ∼20 °C and H2O (30 mL) was added
with vigorous stirring. The organic layer was separated from the
aqueous one; the latter was washed with ether (4½10 mL). The
organic phases were combined, dried with CaCl2, concentrated
in vacuo, and chromatographed on Silufol plates using a 4 : 1
hexane—ether solvent system to give the following products:
— the initial complex 1 (10 mg, 10%);7,8
(—COOH); 1537 w (—CO2 ). 1H NMR (100 ÌHz, ac-
–
etone-d6), δ: 4.80, 4.69, 4.49, 4.40 (all m, 2 H each, CH);
–9.98 (s, 1 H, µ-H). Found (%): C, 22.88; H, 1.01; Fe, 4.19;
Os, 50.14. C22H10FeO14Os3. Calculated (%): C, 22.40; H, 0.89;
Fe, 4.98; Os, 50.76.
1
— a yellow-orange solid (22 mg, 30%), whose IR and H
NMR spectra completely coincided with the corresponding
spectra of (µ-H)Os3(µ-Cl)(CO)10;21
—
1-{1,2-µ,η2-(O,O´)-carboxylato-(1,2-µ-hydrido)-
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 00-03-
33011à).
1,1,1,1,2,2,2,3,3,3-decacarbonyl-triangulo-triosmium}-2-acetyl-
ferrocene (6) (9.2 mg, 9.7%), an orange crystalline solid.

2458
Russ.Chem.Bull., Int.Ed., Vol. 50, No. 12, December, 2001
Maksakov et al.
15. P. Rimmelin and J. Sommer, J. Organomet. Chem., 1976,
114, 175.
References
16. E. D Korniets, V. A. Maksakov, L. K. Kedrova, N. I.
Shakot´ko, and S. P. Gubin, Izv. Akad. Nauk SSSR, Ser.
Khim., 1983, 435 [Bull. Acad. Sci. USSR, Div. Chem. Sci.,
1983, 32, 393 (Engl. Transl.)].
17. E. D. Korniets, L. K. Kedrova, and N. G. Maksimov,
Izv. Akad. Nauk SSSR, Ser. Khim., 1987, 2064 [Bull.
Acad. Sci. USSR, Div. Chem. Sci., 1987, 36, 1914 (Engl.
Transl.)]
18. V. V. Krivykh, O. A. Kizas, E. V. Vorontsov, F. M.
Dolgushin, A. I. Yanovsky, Yu. T. Struchkov, and A. A.
Koridze, J. Organomet. Chem., 1996, 508, 39.
19. Wong Wai-Yeung and Wong Wing-Tak, J. Chem. Soc.,
Dalton Trans., 1995, 3995.
20. A. Z. Kreindlin, P. V. Petrovskii, I. G. Barakovskaya,
L. M. Epshtein, E. S. Shubina, and M. I. Rybinskaya, Izv.
Akad. Nauk, Ser. Khim., 1999, 180 [Russ. Chem. Bull.,
1999, 48, 179 (Engl. Transl.)].
1. M. H. A. Benvenutti, P. B. Hitchcok, J. F. Mixon, and
M. D. Vargas, J. Chem. Soc., Chem. Commun., 1996, 441.
2. A. A. Koridze, V. I. Zdanovich, A. M. Shelomov, V. Yu.
Lagunova, P. V. Petrovskii, and A. N. Peregudov, Organo-
metallics, 1997, 16, 2285.
3. R. D. Adams and B. Qu, Organometallics, 2000, 19, 4090.
4. W. R. Cullen, S. J. Rettig, and H. Zhang, Can. J. Chem.,
1996, 74, 2167.
5. V. A. Maksakov and S. P. Gubin, Koord. Khim., 1984, 29,
689 [Coord. Chem. USSR, 1984, 29 (Engl. Transl.)].
6. N. V. Podberezskaya, V. A. Maksakov, I. V. Slovokhotova,
S. P. Babailov, A. V. Virovets, and V. P. Kirin, Zh. Struktur.
Khim., 1999, 40, 1128 [Russ. J. Struct. Chem., 1999, 40
(Engl. Transl.)].
7. V. A. Maksakov, I. V. Bragina, and S. P. Babailov,
IV Vsesoyuzn. konf. metalloorg. Khim. [IV All-Union Conf.
on Organometallic Chem.], Abstrs., Kazan', 1988, 3, 98 (in
Russian).
21. A. J. Deeming and S. Hasso, J. Organomet. Chem., 1976,
114, C. 313.
8. S.-M. Lee, K.-K. Cheng, and W.-T. Wong, J. Organomet.
Chem., 1996, 506, 77.
9. B. Floris, G. Illuminati, and G. Ortaggi, Tetrahedron Lett.,
1972, 269.
10. G. Cerichelli, G. Illuminati, G. Orteggi, and A. M. Ginliani,
J. Organomet. Chem., 1977, 127, 357.
22. A. N. Nesmeyanov, L. A. Kazitsyna, B. V. Lokshin, and
I. I. Kritskaya, Dokl. Akad. Nauk SSSR, 1957, 117, 423
[Dokl. Chem., 1957 (Engl. Transl.)]; G. G. Dvoryantseva,
M. M. Struchkova, Yu. N. Sheinker, Dokl. Akad.
Nauk SSSR, 1963, 152, 617 [Dokl. Chem., 1963 (Engl.
Transl.)].
11. E. G. Perevalova, M. D. Reshetova, and K. I. Grandberg,
Metody elementoorganicheskoi Khim., Zhelezoorganicheskie
soedineniya. Ferrotsen [Methods of Organoelement Chemis-
try. Organoiron Compounds. Ferrocene], Eds. A. N.
Nesmeyanov and K. A. Kocheshkov, Nauka, Moscow,
1983, 155 (in Russian).
12. M. I. Rybinskaya, A. Z. Kreindlin, L. N. Kiseleva, N. V.
Kruglova, P. V. Petrovskii, L. M. Epshtein, A. N. Krylov,
E. S. Shubina, and U. Turpeinen, Izv. Akad. Nauk, Ser.
Khim., 1995, 2486 [Russ. Chem. Bull., 1995, 44, 2386
(Engl. Transl.)].
23. M. Castagnola, B. F. Floris, G. Illuminati, and G. Ortaggi,
J. Organomet. Chem., 1973, 60, C17.
24. E. G. Perevalova, M. D. Reshetova, K. I. Grandberg, and
A. N. Nesmeyanov, Izv. Akad. Nauk SSSR, Ser. Khim.,
1964, 1901 [Bull. Acad. Sci. USSR, Div. Chem. Sci., 1964,
13, 1808 (Engl. Transl.)].
25. K. Nakamoto, Infrared and Raman Spectra of Inorganic and
Coordination Compounds, J. Wiley and Sons, Inc., New
York—Chichester—Brisbane—Toronto—Singapore, 1986.
26. B. F. G. Johnson, J. Lewis, and D. A. Pippard, J. Chem.
Soc., Dalton Trans., 1981, 407.
13. G. A. Olah and Y. R. Mo, J. Organomet. Chem., 1973,
60, 311.
14. M. I. Rybinskaya, Izv. Akad. Nauk, Ser. Khim., 1992, 1083
[Bull. Russ. Acad. Sci., Div. Chem. Sci., 1992, 41, 850
(Engl. Transl.)].
Received March 12, 2001;
in revised form October 11, 2001