Formation of N-methylated cyclic ligand systems from unusual reactions between trimethylamine N-oxide and acetylenes on Fe3Te 2(CO)9 and contrast with reactions on Fe3e 2(CO)9 (E = S, Se)

Article abstract of DOI:10.1021/om701290c

Activation of C-H bonds of N-methyl groups has been achieved on cluster support. Use of a noncoordinating solvent in the reaction of Me₃NO · 2H₂O, acetylenes, and Fe₃Te₂(CO) ₉ leads to activation of N-methyl groups of Me₃NO and formation of N,N-dimethyldihydropyrrole (1) and N,N′- dimethylhexahydropyrimidine (2) ring systems. The NMe₃ ligand, resulting from TMNO, is retained on the metal cluster due to the absence of a coordinating solvent and reacts with incoming acetylenes. In contrast, activation of the N-methyl groups of Me₃NO is not observed in the reaction using Fe₃S₂(CO)9, which yields complexes with vinylferrocene (3) and 1,4-diferrocenylbuta-1,3-diene-2,3-dithio (4) units attached to Fe₂S₂(CO)₆. All new compounds have been structurally characterized by single-crystal X-ray diffraction studies.

Full text of DOI:10.1021/om701290c

5094
Organometallics 2008, 27, 5094–5098
Formation of N-Methylated Cyclic Ligand Systems from Unusual
Reactions between Trimethylamine N-Oxide and Acetylenes on
Fe3Te2(CO)9 and Contrast with Reactions on Fe3E2(CO)9
(E ) S, Se)
Pradeep Mathur,*,†,‡ Amrendra K. Singh,† Jamini R. Mohanty,† Saurav Chatterjee,† and
Shaikh M. Mobin‡
Department of Chemistry and National Single Crystal X-ray Diffraction Facility, Indian Institute of
TechnologysBombay, Bombay 400 076, India
ReceiVed December 25, 2007
Activation of C-H bonds of N-methyl groups has been achieved on cluster support. Use of a
noncoordinating solvent in the reaction of Me3NO · 2H2O, acetylenes, and Fe3Te2(CO)9 leads to activation
of N-methyl groups of Me3NO and formation of N,N-dimethyldihydropyrrole (1) and N,N′-dimethyl-
hexahydropyrimidine (2) ring systems. The NMe3 ligand, resulting from TMNO, is retained on the metal
cluster due to the absence of a coordinating solvent and reacts with incoming acetylenes. In contrast,
activation of the N-methyl groups of Me3NO is not observed in the reaction using Fe3S2(CO)9, which
yields complexes with vinylferrocene (3) and 1,4-diferrocenylbuta-1,3-diene-2,3-dithio (4) units attached
to Fe2S2(CO)6. All new compounds have been structurally characterized by single-crystal X-ray diffraction
studies.
Scheme 1
Introduction
Trimethylamine N-oxide (TMNO) has been widely used for
the activation of coordinatively saturated metal carbonyl
complexes and clusters via oxidative decarbonylation.1 Tradi-
tionally it has been used for the replacement of CO by a donor
solvent molecule, which is further replaced by the desired
ligand.2 However, in contrast to the large number of reports on
the decarbonylating behavior of TMNO in coordinating solvents
such as acetonitrile, little is known about its reactivity in
coordinatively “innocent” solvents.3 We have earlier reported
that, in the presence of acetonitrile/TMNO, Fe3E2(CO)9 (E )
S, Se, Te) complexes are converted into Fe2E2(CO)6, which can
react with coordinatively unsaturated organometallic fragments
to form mixed-metal clusters. Thus, the reaction of Fe3Te2(CO)9
with CpMo(CO)3(CtCPh) in acetonitrile/TMNO gives a mixed-
metal chalcogen cluster with an η1-acetylide group.4 Addition
of substituted alkynes and of carbenes and alkynyl Fisher
carbenes to the E-E′ bonds in Fe2EE′(CO)6 also occurs readily
under facile conditions.5 For instance, a reaction between
Fe2Te2(CO)6 and diazomethane results in the insertion of :CH2
into the Te-Te bond and gives Fe2(CO)6(µ-TeCH2Te).6 In the
past, we have used the compounds Fe3E2(CO)9 and Fe2(CO)6(µ-
E2) (E ) S, Se, Te) as supports to carry out numerous types of
carbon-carbon bond formations resulting from coupling be-
tween metal acetylides.7 In this paper, we report a novel
N-methyl activation in a reaction between acetylenes and
TMNO · 2H2O on a Fe3Te2(CO)9 cluster. Also, a contrast in the
behavior of Fe2S2(CO)9 is observed in its reaction with
ferrocenylacetylene in the presence of TMNO · 2H2O, where no
activation of N-methyl groups takes place.
* To whom correspondence should be addressed. E-mail: mathur@
iitb.ac.in.
† Department of Chemistry.
‡ National Single Crystal X-ray Diffraction Facility.
(1) Luh, T. Y. Coord. Chem. ReV. 1984, 60, 255, and references therein.
(2) (a) Hor, T. S. A. J. Organomet. Chem. 1987, 319, 213. (b) Hor,
T. S. A. Inorg. Chim. Acta 1987, 128, L3. (c) Hor, T. S. A.; Chee, S. M.
J. Organomet. Chem. 1987, 331, 23. (d) Hor, T. S. A.; Chan, H. S. O.
Inorg. Chim. Acta 1989, 160, 53. (e) Hor, T. S. A.; Chan, H. S. O.; Leong,
Y. P.; Tan, M. M. J. Organomet. Chem. 1989, 373, 221. (f) Adams, R. D.;
Qu, B. J. Organomet. Chem. 2001, 619, 271. (g) Adams, R. D.; Qu, B.;
Smith, M. D. J. Organomet. Chem. 2001, 637-639, 514. (h) Lee, F. Y.;
Huang, J. J.; Chen, Y. J.; Lin, K. J.; Lee, G. H.; Peng, S. M.; Hwu, J. R.;
Lu, K. L. J. Organomet. Chem. 2005, 690, 441.
(3) One report of the use of TMNO in an innocent solvent is the reaction
of Os6(CO)18 with TMNO in hexane to form [HOs6(CO)17]-: Johnson,
B. F. G.; Lewis, J.; Pearsall, M. A.; Scott, L. G. J. Organomet. Chem.
1991, 402, C27.
(5) (a) Mathur, P.; Chakrabarty, D.; Mavunkal, I. J. J. Cluster Sci. 1993,
4, 351. (b) Mathur, P. AdV. Organomet. Chem. 1997, 41, 243.
(6) Mathur, P.; Reddy, V. D. J. Organomet. Chem. 1990, 387, 193.
(7) (a) Mathur, P.; Ahmed, M. O.; Dash, A. K.; Walawalkar, M. G.
J. Chem. Soc., Dalton Trans. 1999, 1795. (b) Mathur, P.; Ahmed, M. O.;
Dash, A. K.; Kaldis, J. H. Organometallics 2000, 19, 941. (c) Mathur, P.;
Srinivasu, C.; Ahmed, M. O.; Puranik, V. G.; Umbarkar, S. B. J. Organomet.
Chem. 2002, 659, 196. (d) Mathur, P.; Ahmed, M. O.; Kaldis, J. H.;
McGlinchey, M. J. Dalton Trans. 2002, 619.
(4) Mathur, P.; Bhunia, A. K.; Kumar, A.; Chatterjee, S.; Mobin, S. M.
Organometallics 2002, 21, 2215.
10.1021/om701290c CCC: $40.75
2008 American Chemical Society
Publication on Web 09/06/2008

Formation of N-Methylated Cyclic Systems
Organometallics, Vol. 27, No. 19, 2008 5095
Scheme 2.a
a
Loss of one H from a methyl group and addition of CH2NMe2
group to ferrocenylacetylene on a Fe3Te2(CO)9 support results in the
formation of 1. Loss of two H atoms from two methyl groups of one
NMe3 group and loss of one H and a loss of a methyl group from a
second NMe3 and addition of phenylacetylene leads to the formation
of the hexahydropyrimidine ring of 2.
Figure 1. Molecular structure of 1 showing 50% probability
ellipsoids. Hydrogen atoms are omitted for clarity. Selected bond
lengths (Å) and angles (deg): Fe(1)-Fe(2) ) 2.6052(6), Fe(1)-Te(1)
) 2.5610(5), Fe(1)-Te(2) ) 2.5381(4), Fe(3)-Te(1) ) 2.6090(5),
Fe(3)-C(14) ) 2.008(3), Te(2)-C(14) ) 2.136(3), C(13)-C(14)
) 1.340(4), Fe(3)-N(1) ) 2.092(3); Te(2)-Fe(1)-Te(1) )
83.956(14), Te(2)-Fe(2)-Te(1) ) 83.920(14).
and attached to the wingtip Te atoms of a Fe2Te2 butterfly unit.
Each iron atom retains the three terminal carbonyls. The pyrrole
ring lies approximately perpendicular to the Fe-Fe axis, with
the ferrocenyl substituent oriented away from the carbonyl
groups of the Fe2(CO)6 unit. The bond length C(14)-Te(2) )
2.1363(3) Å is similar to the C-Te bond distances in
Fe2Te2(CH2)(CO)6 (2.157(12), 2.169(9) Å) reported earlier.8 The
Te-Te distance, Te(1)-Te(2) ) 3.4106 Å, is slightly longer
than those in complexes of the type Fe2Te(X)TeCO)6 (X ) CH2,
3.114(1) Å; X ) Fe(CO)3(PPh3), 3.138(1) Å), indicating a
greater opening of the Fe2Te2 butterfly unit to accommodate
the ferra-N,N-dimethylhydropyrrole ring.8,9 A more open Fe2Te2
butterfly unit is also evident from the average Te-Fe-Te bond
angles of ca. 84° in 1 and 83° in 2 as compared to average
Te-Fe-Te angles in Fe2Te(X)TeCO)6 complexes reported
earlier (X ) CH2, Fe(CO)3(PPh3), 75°; X ) Ru3(CO)11,
79°).8-10
The molecular structure of 2 features an N,N′-dimethyl-5-
phenylhexahydropyrimidine unit attached to a Fe3Te2(CO)8CH
framework. Whereas in 1 the ferra-N,N-dimethyldihydropyrrole
ring is formally formed by coupling of one trimethylamine with
a ferrocenylacetylene molecule, in 2 two trimethylamine ligands
from two TMNO groups are incorporated during cyclization
and a six-membered ring is formed. The two nitrogen atoms of
2 are attached to the iron cluster by donating their lone pairs to
Fe(3). The two N-Fe bond distances in 2, N(1)-Fe(3) )
2.0854(5) Å and N(2)-Fe(3) ) 2.0844(5) Å, are similar to the
distance N(1)-Fe(3) ) 2.0916(3) Å in 1. The bond length
C(1)-Te(1) ) 2.1927(5) Å matches well with those in 1 and
Fe2Te2(CH2)(CO)6 reported earlier.9 The Te-Te distance,
Te(1)-Te(2) ) 3.3725(5) Å, is also similar to that in 1,
indicative of a similar extent of opening of the Fe2Te2 butterfly.
Figure 2. Molecular structure of 2 showing 50% probability
ellipsoids. Hydrogen atoms are omitted for clarity. Selected bond
lengths(Å)andangles(deg):Fe(1)-Fe(2))2.5919(11),Fe(1)-Te(1)
) 2.5359(9), Fe(1)-Te(2) ) 2.5563(9), Fe(3)-Te(2) ) 2.5792(9),
Fe(3)-N(1) ) 2.085(5), Fe(3)-N(2) ) 2.086(5), C(1)-Fe(3) )
2.010(6),C(1)-Te(1))2.193(6),C(1)-C(2))1.535(7);Te(2)-Fe(1)-Te(1)
) 82.95(3), Te(2)-Fe(2)-Te(1) ) 82.77(3).
Results and Discussion
Compounds 1 and 2 (Scheme 1) were obtained from a room-
temperature reaction of Fe3Te2(CO)9, TMNO · 2H2O, and fer-
rocenyl- or phenylacetylene, respectively, in hexane solution.
Use of hexane solvent is significant in this reaction, as when
acetonitrile or dichloromethane was used, only decomposition
resulted.
Formation of the new clusters formally involves reaction
between one or two molecules of trimethylamine and ferroce-
nylacetylene or phenylacetylene, respectively, on a ditellurot-
riiron cluster. It is likely that initially the adduct
[{Fe2Te2(CO)6}{Fe(CO)3NMe3}] is formed, in which a ferro-
cenylacetylene molecule formally inserts between the coordi-
nated trimethylamine and a Te of the {Fe2Te2(CO)6} unit
The IR spectra of both compounds show the presence of a
terminal carbonyl stretching pattern typically found in com-
pounds containing the Fe2(CO)6 moiety. 1H NMR spectra show
signals for N-methyl and methylene protons along with signals
for Cp protons in 1 and phenyl ring protons in 2. Crystals of 1
and 2 were grown by slow evaporation of their solutions in
hexane/dichloromethane mixtures at 0 °C, and single-crystal
X-ray analysis was performed for unambiguous molecular
structure determinations. The molecular structures of 1 and 2
are shown in Figures 1 and 2, respectively.
(8) Mathur, P.; Reddy, V. D.; Bohra, R. J. Organomet. Chem. 1991,
401, 339.
(9) Lesch, D. A.; Rauchfuss, T. B. Organometallics 1982, 3, 499.
(10) Mathur, P.; Mavunkal, I. J.; Rheingold, A. L. J. Chem. Soc., Chem.
Commun. 1989, 382.
The structure of 1 consists of a ferra-N,N-dimethyldihydro-
pyrrole ring containing the ferrocenyl group at the 3-position

5096 Organometallics, Vol. 27, No. 19, 2008
Mathur et al.
Scheme 3
(Scheme 2). In the process, a C-H bond of one methyl group
of trimethylamine is activated and transformed into an iminium
group, which adds to the R-carbon of the ferrocenylacetylene.
In 1, there is no net loss of carbonyl groups. Although not
isolated, a similar type of iminium formation has been invoked
in the mechanism proposed for the formation of [HOs6(CO)17]-
from the reaction of Os6(CO)18 with Me3NO in a noncoordi-
nating solvent.3
Compound 2 can be thought to form by an initial formation
of an intermediate, [{Fe2Te2(CO)6}{Fe(CO)2(NMe3)2}], arising
from addition of one trimethylamine and substitution of one
carbonyl by a second trimethylamine molecule. A formal
addition reaction occurs between one molecule of phenylacety-
lene and two molecules of trimethylamine. One of the methyl
groups from one trimethylamine molecule undergoes conversion
to a methylene group, and in the second trimethylamine there
is a loss of one methyl group while another methyl group
converts to a methylene group (Scheme 2). The square-
pyramidal Fe3(CO)9Te2 undergoes a structural transformation
identical with that observed in 1.
Although the mechanistic pathway is uncertain at this time,
the absence of a coordinating solvent is crucial for the formation
of 1 and 2. Use of a noncoordinating solvent such as hexane
ensures that the trimethylamine ligand, originating from TMNO,
remains coordinated to the metal and can engage in additions
with ferrocenyl- or phenylacetylene on the ditellurotriiron cluster
support.
In order to investigate the scope and limitation of using
TMNO as a reagent in an innocent solvent in the reaction with
chalcogen-bridged clusters, we have looked at the reactions of
Fe3Se2(CO)9 and Fe3S2(CO)9 with ferrocenylacetylene and
TMNO. Several compounds were observed in the reaction when
Fe3Se2(CO)9 was used; however, none of these were stable
enough to enable their isolation and characterization. In contrast,
the reaction in which Fe3S2(CO)9 was used formed two stable
products, compounds 3 and 4 (Scheme 3).
For both compounds the IR spectra showed a carbonyl
stretching pattern similar to that seen in the spectra of 1 and 2
and characteristic of a Fe2(CO)6 unit. 1H NMR spectra of
compounds 3 and 4 each show signals for ferrocenyl groups
and peaks at δ 6.57 ppm (3) and δ 6.53 and 6.61 ppm (4) for
olefinic protons. Crystals of 3 and 4 were grown by slow
evaporation of their solution in hexane/dichloromethane mixtures
at 0 °C and single crystal X-ray analysis was performed for
unambiguous molecular structure determinations.
The molecular structure of 3, shown in Figure 3, can be
described as consisting of an open butterfly Fe2(CO)6 unit in
which the two
FcC(H)dCFe(CO)3group. The Fe-Fe (2.579(2), 2.714(2) Å) and
Fe-S (2.227(3)-
S
atoms are bridged by
a
2.252(3) Å) bond distances of 3 are similar to those ob-
served in Fe2(CO)6(µ-SXS) types of complexes (X ) FcCdCH,
Fe-Fe ) 2.4755(12) Å, Fe-S ) 2.2658(16)-2.2847(18) Å;
FcCdC(H)C(O), Fe-Fe ) 2.5077(3) Å, Fe-S ) 2.2594(4)-
2.2648(5) Å).11 The CdC double-bond distance in the vi-
nylidene unit of 3 (1.437(17) Å) is comparable to those in 1
(1.340(4) Å) and other vinylidene complexes (∼1.33 Å).12
The structure of 4 differs from that of 3, in that a
FcC(H)dCCdC(H)Fc butadiene unit bridges the two S atoms
of a Fe2(CO)6 unit and is coordinated to a Fe(CO)3 unit in an
η2:η2 fashion (Figure 4). Structure of 4 can be described as
arising from a formal addition of a 1,4-diferrocenylbuta-1,3-
diene-2,3-dithiolate to a Fe2(CO)6 unit. Further, a Fe(CO)3 unit
engages in bonding to the two double bonds of the diene unit.
Figure 3. Molecular structure of 3 showing 50% probability
ellipsoids. Hydrogen atoms are omitted for clarity. Selected bond
lengths (Å) and angles (deg): Fe(1)-Fe(2) ) 2.579(2), Fe(2)-Fe(3)
) 2.714(2), Fe(3)-C(10) ) 1.989(10), S(1)-C(10) ) 1.651(14),
C(10)-C(11) ) 1.437(17), Fe(1)-S(1) ) 2.243(3), Fe(1)-S(2) )
2.242(3), Fe(2)-S(1) ) 2.250(3), Fe(2)-S(2) ) 2.252(3), Fe(3)-S(2)
) 2.227(3); S(1)-Fe(2)-S(2) ) 85.42(11), C(11)-C(10)-S(1) )
122.2(8), C(11)-C(10)-Fe(3) ) 126.3(10).
Figure 4. Molecular structure of 4 showing 50% probability
ellipsoids. Hydrogen atoms are omitted for clarity. Selected bond
lengths(Å)andangles(deg):C(10)-C(14))1.465(10),C(10)-C(11)
) 1.415(10), C(11)-C(12) ) 1.403(9), C(12)-C(13) ) 1.428(9),
C(13)-C(24) ) 1.470(9), S(1)-C(11) ) 1.807(7), S(2)-C(12) )
1.794(6), Fe(2)-S(1) ) 2.269(2), Fe(3)-S(1) ) 2.288(2);
S(2)-Fe(2)-S(1) ) 80.24(7), C(12)-C(11)-C(10) ) 118.7(6),
C(11)-C(12)-C(13) ) 123.1(6).

Formation of N-Methylated Cyclic Systems
Organometallics, Vol. 27, No. 19, 2008 5097
Scheme 4
Table 1. Crystal Data and Structure Refinement Parameters for Compounds 1-4
1
2
3
4
empirical formula
formula wt
temp, K
C24H17Fe4NO9Te2
941.99
150(2)
C22H20Cl2Fe3N2O8Te2
934.05
150(2)
C21H10Fe4 O9S2
693.81
150(2)
C33H20Fe5O9S2
903.86
120(2)
cryst syst
space group
a, Å
b, Å
c, Å
orthorhombic
P212121
9.3250(2)
15.1222(3)
20.0419(4)
90
monoclinic
P21/n
9.8877(2)
13.3922(3)
22.1362(5)
90
91.621(2)
90
2930.06(11)
4
monoclinic
P21/c
13.6715(12)
7.1808(5)
24.9489(2)
90
94.762(7)
90
2440.8(3)
4
monoclinic
P2/c
10.1722(8)
12.7137(8)
25.4348(16)
90
101.025(6)
90
3228.7(4)
4
R, deg
ꢀ, deg
90
90
γ, deg
V, Å3
2826.20(10)
4
2.214
4.087
1792
Z
Dcalcd, Mg m-3
abs coeff, mm-1
F(000)
2.117
3.646
1784
1.888
2.551
1376
1.859
2.378
1808
cryst size, mm
θ range, deg
index ranges
0.38 × 0.33 × 0.31
2.98-25.00
-11 e h e 11
-17 e k e 17
-23 e l e 23
24 727/4954
0.0261
0.32 × 0.23 × 0.21
3.04-24.99
-11 e h e 11
-15 e k e 15
-26 e l e 26
23 848/5135
0.0338
0.26 × 0.22 × 0.18
2.95-25.00
-16 e h e 16
-8 e k e 8
-29 e l e 29
21 527/4299
0.1243]
0.27 × 0.21 × 0.18
3.20-25.00
-12 e h e 11
-15 e k e 15
-30 e l e 30
20 197/5664
0.0800
no. of collected/unique rflns
R(int)
no. of data/ restraints/params
goodness of fit on F2
final R indices (I > 2σ(I))
4954/0/363
1.090
5135/0/354
1.113
4299/14/325
1.100
5664/0/450
0.999
R1 ) 0.0162
wR2 ) 0.0370
R1 ) 0.0176
wR2 ) 0.0381
0.740 and -0.257
R1 ) 0.0402
wR2 ) 0.1041
R1 ) 0.0479
wR2 ) 0.1108
1.725 and -1.120
R1 ) 0.0774
wR2 ) 0.1543
R1 ) 0.1424
wR2 ) 0.1802
2.445 and -0.923
R1 ) 0.0625
wR2 ) 0.1510
R1 ) 0.0969
wR2 ) 0.1636
1.308 and -0.754
R indices (all data)
largest diff peak and hole, e Å-3
The bond parameters of Fe2(CO)6S2 and the butadiene-Fe(CO)3
unit in 4 are unexceptional. The distance C(11)-C(12) )
1.403(9) Å is also comparable to the corresponding bond in
Fe2(CO)6{µ-SC(Fc)dC(H)S} (1.313(8) Å).11
organic molecules arising from addition reactions between
trimethylamine N-oxide and substituted acetylenes. In contrast,
incorporation of an NMe3 group and N-Me activation were not
observed in the reaction with the Fe3S2(CO)9 cluster, while
reaction with Fe3Se2(CO)9 did not yield any stable product.
The contrast between reactions of the Te compound from
those of the Se- and S-bridged triiron nonacarbonyls is not
unexpected and can be ascribed to the much larger difference
in the size and basicity of Te as compared with those of its
chalcogen congeners.
The formation of compound 3 involves a formal hydride shift
of ferrocenylacetylene and an insertion of the vinylidene unit
:CdC(H)Fc thus formed into a Fe-S bond of Fe3S2(CO)9
cluster. We also carried out the reaction using deuterium-labeled
ferrocenylacetylene (Scheme 4). The 1H NMR spectra of 5 and
6 showed almost complete disappearances of peaks for the
CdC(H)Fc and FcC(H)CC(H)CFc. Their mass spectra showed
molecular ion peaks shifted up by one and two units, relative
to those of 3 and 4, respectively, thus confirming that the
vinylidene CdC(H)Fc is indeed formed by an intramolecular
hydride shift. Although compound 6 can be regarded to formally
also be obtained by addition of a second vinylidene unit to 5,
we were unable to effect this transformation on addition of
excess ferrocenylacetylene to compound 5.
Experimental Section
General Procedure. Reactions and manipulations were per-
formed using standard Schlenk line techniques under an atmosphere
of prepurified argon. Solvents were purified, dried, and distilled
under an argon atmosphere prior to use. Infrared spectra were
recorded on a Nicolet 380 FT-IR spectrometer as hexane solutions
in 0.1 mm path length NaCl cells and NMR spectra on a Varian
VXRO-300S spectrometer in CDCl3. Elemental analyses were
performed on a Carlo-Erba automatic analyzer. Iron pentacarbonyl
and ferrocene were purchased from Fluka and Spectrochem,
respectively, and these were used without further purification.
Phenylacetylene was purchased from Aldrich and used without
further purification. TLC plates were purchased from Merck (20
× 20 cm, silica gel 60 F254). Photochemical reactions were carried
out using double-walled quartz vessels and a 125 W immersion
type mercury lamp manufactured by Applied Photophysics Ltd.
Conclusion
The results reported here demonstrate the utility of trimethy-
lamine N-oxide as a reagent for addition to unsaturated
molecules in a noncoordinating solvent, to form an N-hetero-
cyclic ligand system. Formation of the metalladihydropyrrole
and hexahydropyrimidine rings on the telluro-iron carbonyl
support is unique and may be prototypical of formation of other

5098 Organometallics, Vol. 27, No. 19, 2008
Mathur et al.
Reaction of Fe3Te2(CO)9, TMNO · 2H2O, and Ferrocenyl-
or Phenylacetylene. TMNO · 2H2O (55 mg 0.5 mmol) was added
to a round-bottomed side-arm flask containing ferrocenylacetylene
(210 mg, 1 mmol) and Fe3Te2(CO)9 (338 mg, 0.5 mmol) in hexane
(30 mL). The reaction mixture was stirred at room temperature for
4 h. At the end of the reaction, the reaction mixture was diluted
with CH2Cl2 and filtered through a Celite pad. The filtrate was
concentrated, and the residue was purified through TLC with
dichloromethane/petroleum ether (30/70) as eluent to give pure
products.
Celite pad. The filtrate was concentrated and chromatographed on
silica gel TLC plates; compounds 5 and 6 were obtained as green
and red bands, respectively.
5. Yield: 20%. IR (cm-1, νCO): 2059 (s), 2021 (vs) 1981(vs),
1962 (s, br). 1H NMR (CDCl3): δ 4.37 (s, 5H, η5-C5H5), 4.24-4.51
(m, 4H, η5-C5H4). MS (m/z, ES+): 694.7230 (M+).
6. Yield: 18%. IR (cm-1, νCO): 2080 (s), 2045 (vs), 2009 (vs),
1947 (s). 1H NMR (CDCl3): δ 4.27 (s, 5H, η5-C5H5), 4.41 (s, 5H,
η5-C5H5), 4.32-4.91 (m, 8H, η5-C5H4). MS (m/z, ES+): 905.7090
(M+).
1. Yield: 21%. Anal. Calcd for C24H18Fe4NO9Te2: C, 30.60; H,
Crystal Structure Determination for 1-4. Suitable X-ray-
quality crystals of 1, 2, and 4 could be grown from a dichlo-
romethane/n-hexane solvent mixture at 0 °C, and X-ray diffraction
studies were undertaken. For compound 3, we were unable to obtain
single crystals of sufficiently good quality, and consequently, the
data collected and subsequent structure solution are of modest
quality. Relevant crystallographic data and details of measurements
are given in Table 1. X-ray crystallographic data were collected
from single-crystal samples of 1 (0.38 × 0.33 × 0.31 mm3), 2 (0.32
× 0.23 × 0.21 mm3), 3 (0.26 × 0.22 × 0.18 mm3), and 4 (0.27 ×
0.21 × 0.18 mm3) mounted on a Oxford Diffraction XCALIBUR-S
CCD system equipped with graphite-monochromated Mo KR
radiation (0.710 73 Å). The data were collected by the ω-2θ scan
mode, and absorption correction was applied by using Multi-Scan.
The structure was solved by direct methods (SHELXS-97) and
refined by full-matrix least squares against F2 using SHELXL-97
software.13 Non-hydrogen atoms were refined with anisotropic
thermal parameters. All hydrogen atoms were geometrically fixed
and refined using a riding model.
1.82; N, 1.49. Found: C, 29.54; H, 2.13; N, 1.36. IR (cm-1, νCO):
1
2053 (s), 2016 (vs) 1972 (vs), 1956 (s, br). H NMR (CDCl3): δ
4.33 (s, 5H, η5-C5H5), 4.21-4.43 (m, 4H, η5-C5H4), 3.61 (s, 2H,
-CH2-) 2.37 (s, 6H, CH3-N). MS (m/z, ES+): 941.8814 (M+).
2. Yield: 32%. Anal. Calcd for C21H18Fe3N2O8Te2: C, 29.70; H,
2.14; N, 3.30. Found: C, 28.96; H, 2.73; N, 3.51. IR (cm-1, νCO):
2047 (s), 2006 (vs), 1989 (vs), 1947 (s). 1H NMR (CDCl3): δ
7.31-7.56 (m, 5H, C6H5), δ 2.91-3.34 (m, 6H, -CH2-), 2.29 (s,
6H, CH3-N). MS (m/z, ES+): 849.1247 (M+).
Reaction of Fe3S2(CO)9, TMNO · 2H2O, Ferrocenylacetylene.
TMNO · 2H2O (55 mg 0.5 mmol) was added to a round-bottomed
side-arm flask containing ferrocenylacetylene (210 mg, 1 mmol)
and Fe3S2(CO)9 (242 mg, 0.5 mmol) in hexane (30 mL). The
reaction mixture was stirred at room temperature for 4 h. At the
end of the reaction, the reaction mixture was diluted with CH2Cl2
and filtered through a Celite pad. The filtrate was concentrated and
chromatographed on silica gel TLC plates; compounds 3 and 4 were
obtained as green and red bands, respectively.
3. Yield: 23%. Anal. Calcd for C21H10O9Fe4S2: C, 36.35; H, 1.45;
S, 9.24. Found: C, 35.78; H, 2.03; S, 9.54. IR (cm-1, νCO): 2059
(s), 2021 (vs) 1981 (vs), 1962 (s, br). 1H NMR (CDCl3): δ 4.37 (s,
5H, η5-C5H5), 4.24-4.51 (m, 4H, η5-C5H4), 6.57 (s, 1H, FcCH).
MS (m/z, ES+): 693.7134 (M+).
Acknowledgment. P.M. is grateful to the Department of
Science and Technology for research funds under the J.C.
Bose fellowship program, and A.K.S. thanks the Council of
Scientific and Industrial Research for an SPM Fellowship.
4. Yield: 19%. Anal. Calcd for C33H20Fe5O9S2: C, 43.82; H, 2.23;
S, 7.08. Found: C, 43.37; H, 2.70; S, 7.56. IR (cm-1, νCO): 2080
Supporting Information Available: CIF files giving crystal-
lographic data (excluding structure factors) for 1-4. This material
is available free of charge via the Internet at http://pubs.acs.org.
These data have also been deposited with the Cambridge Crystal-
lographic Data Center as Supplementary Publication Nos. CCDC-
661651 (1), CCDC-661652 (2) CCDC-695954 (3) and CCDC-
695955 (4). Copies of the data can be obtained free of charge on
application to the CCDC, 12 Union Road, Cambridge CB2 1EZ,
U.K. (fax (+44) 1223-336-033; e-mail: deposit@ccdc.cam.ac.uk).
1
(s), 2045 (vs), 2009 (vs), 1947 (s). H NMR (CDCl3): δ 4.27 (s,
5H, η5-C5H5), 4.41 (s, 5H, η5-C5H5), 4.32-4.91 (m, 8H, η5-C5H4),
6.53 (s, 1H, FcCH), 6.61 (s, 1H, FcCH). MS (m/z, ES+): 903.9175
(M+).
Preparation of Deuterium-Labeled Ferrocenylacetylene
and Its Reaction with Fe3S2(CO)9 and TMNO · 2H2O. A ferro-
cenylacetylene (210 mg, 1 mmol) solution in THF (20 mL) at -20
°C was treated with n-BuLi (0.7 mL of 1.6 M in hexanes, 1.1 mmol)
followed by hydrolysis with D2O after 30 min. The product was
extracted with hexane, and the combined solution was washed with
water, dried over Na2SO4, and evaporated under reduced pressure
to give 185 mg (88%) of ferrocenylacetylene-d. TMNO · 2H2O (55
mg 0.5 mmol) was added to a round-bottomed side-arm flask
containing ferrocenylacetylene-d (211 mg, 1 mmol) and Fe3S2(CO)9
(242 mg, 0.5 mmol) in hexane (30 mL). The reaction mixture was
stirred at room temperature for 4 h. At the end of the reaction, the
reaction mixture was diluted with CH2Cl2 and filtered through a
OM701290C
(11) Mathur, P.; Singh, V. K.; Singh, A. K.; Mobin, S. M.; Tho¨ne, C.
J. Organomet. Chem. 2006, 691, 3336.
(12) Akita, M.; Kato, S.-I.; Terada, M.; Masaki, Y.; Tanaka, M.; Moro-
oka, Y. Organometallics 1997, 16, 2392.
(13) Sheldrick, G. M. SHELX 97, Program for Crystal Structure Solution
and Refinement, Release 97-2; University of Go¨ttingen, Go¨ttingen, Germany,
1997.