Novel dinuclear iron(0) complexes from α,β-unsaturated ketones β-positioned with sulfide and sulfoxide groups

Article abstract of DOI:10.1016/j.jorganchem.2003.12.015

The reaction of Fe₂(CO)₉ with α,β-unsaturated ketones analogues containing β-positioned sulfoxide group 2a-2d afforded dinuclear Fe(0) complexes 3a-3d and 5 which were characterized by IR, mass spectrometry, ¹H and ¹³

Full text of DOI:10.1016/j.jorganchem.2003.12.015

Journal of Organometallic Chemistry 689 (2004) 885–893
www.elsevier.com/locate/jorganchem
Novel dinuclear iron(0) complexes from a,b-unsaturated ketones
b-positioned with sulfide and sulfoxide groups
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
M. Carmen Ortega-Alfaro, Nestor Hernandez, Ismael Cerna, Jose G. Lopez-Cortes,
*
ꢀ
Elizabeth Gomez, Ruben A. Toscano, Cecilio Alvarez-Toledano
Instituto de Quꢀımica UNAM, Circuito Exterior, Ciudad Universitaria, Coyoacꢀan, C.P. 04510 Mꢀexico, D.F.
Received 7 October 2003; accepted 1 December 2003
Abstract
The reaction of Fe2(CO)9 with a,b-unsaturated ketones analogues containing b-positioned sulfoxide group 2a–2d afforded di-
nuclear Fe(0) complexes 3a–3d and 5 which were characterized by IR, mass spectrometry, 1H and 13C NMR spectroscopy, the
structures of 3a, 3c and 5 were established by X-ray diffraction analysis.
Ó 2003 Elsevier B.V. All rights reserved.
Keywords: Sulfoxides; Dinuclear Fe(0) complexes; X-ray diffraction
1. Introduction
dithiolane ring, additionally, the coordination of car-
bonyl ketone group is also observed [7].
In recent years, Fe(0) complexes have received much
attraction owing to their structural diversity and wide-
spread application in organic and organometallic
chemistry. Among these interesting compounds especial
attention has been aimed to the study of Fe(0) vinylk-
etone complexes and their transformation into vinylke-
tene Fe(0) complexes as well [1–4].
Our interest in the iron chemistry led us to synthesize
new mono and dinuclear Fe(0) complexes which have
been prepared by reaction of a,b-unsaturated-ketones
analogues containing b-positioned heteroatoms with
Fe2(CO)9 [5–8]. In connection with these studies, we
have reported that a,b-unsaturated ligands possessing
the dithiol group reacts with diiron nonacarbonyl af-
fording dinuclear complexes (a) [6]. However, ligands
which contain an additional conjugated double bond
such as 4-phenyl-1-(1,3-dithiolane-2-ylidene)-3E-bute-
none gives the dinuclear Fe(0) complex (b) in which an
iron atom was inserted into C–S bond by aperture of the
Fe(CO)3
O
S
Fe(CO)3
S
R
(a)
R= o-OCH3, m-OCH3, p-OCH3
CO
OC
S
CO
CO
CO
O
Fe
Fe
S
(b)
In continuing with our studies, we herein report the
synthesis of a,b-unsaturated ketones with sulfoxide
group in b-position 2a–2d, which were reacted with
Fe2(CO)9 affording to dinuclear Fe(0) complexes 3a–3d
exhibiting novel coordination patterns.
* Corresponding author. Fax: +52-5556162217.
E-mail address: cecilio@servidor.unam.mx (C. Alvarez-Toledano).
0022-328X/$ - see front matter Ó 2003 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2003.12.015

886
M.C. Ortega-Alfaro et al. / Journal of Organometallic Chemistry 689 (2004) 885–893
2. Results and discussion
3b and 4 which were isolated by silica-gel chromatog-
raphy, after usual workup. The IR spectra of 3a and 3b
show three absorption bands typical of (M–CO) in the
region of 2089–1954 cmꢀ1. Mass spectrometry show
peaks at m=z ¼ 428 and 490 which correspond to
RCOCH@C(S–CH2–CH2–S)Fe2(CO)5 moiety [Mþ )
28] for 3a and 3b, respectively, in addition, the peaks
corresponding to successive loss of five CO groups were
also detected. These data suggest the formation of a
The sulfoxides 2a–2d were conveniently prepared in
25–38% yield by selective oxidation of 1-(1,3-dithiolane-
2-yliden) acetone derivatives 1a–1d [9,10] using sodium
periodate as oxidizing agent [11] (Scheme 1). All com-
pounds displayed in the IR spectrum the absorption
band for the sulfoxide group around 1045 cmꢀ1. The
NMR data show that the reactions for obtaining com-
pounds 2a–2c proceed with regio- and stereoselectivity
affording exclusively the E isomer. The 1H NMR spectra
of compounds 2a–2c showed four multiplets from 3.0 to
3.9 ppm for methylene groups. In addition, the 13C
NMR spectrum for 2a–2c shows that the carbons bon-
ded to the sulfoxide are shifted upfield (d ꢁ 20) with
respect to the carbon born by the sulfide. In contrast, no
stereoselectivity was observed for the reaction with 1d,
which under the same conditions yielded a mixture of
compounds. From the mixture only 2d could be isolated
and purified by chromatography on alumina, which was
evidenced by 1H and 13C NMR spectra. This fact can be
explained in terms of a strong electronic interaction
between p and d orbital of oxygen and sulfur atoms
through the conjugated system [12].
1
dinuclear complex. The H NMR spectra of 3a and 3b
exhibit singlets at 7.35 and 8.15 ppm, respectively, which
were assigned to vinylic protons. Furthermore, signals
for the methylene groups of 3a and 3b appeared in the
region of 2.62–3.58 ppm, which are slightly shifted to
high frequency with respect to 2a–2b. The 13C NMR
spectra of 3a, 3b show that the carbon attached to the
sulfoxide are shifted to higher frequencies ðd ¼ 10Þ
compared with 2a and 2b, this behavior could be at-
tributed to the presence of iron. Signals at 206.6 and
190.8 ppm were displayed for M–CO group. Complex 4
was obtained as byproduct of the reaction in a very low
yield (2%) as reported elsewhere [7,13].
The reaction of 2a, 2b and Fe2(CO)9 in anhydrous
THF (Scheme 2) led to the formation of complexes 3a,
Fig. 1. ORTEP drawing of compound 4. Thermal ellipsoids at 30%
probability level.
Scheme 1.
OC
CO
CO
OC
S
Fe
S
O
S
O
Fe
S
S
+
Fe2(CO)9
THF
OC
R
S
Fe
(OC)3
Fe(CO)3
R
CO
O
O
2a R= CH3
2b R= C6H5
4
3a R= CH3
3b R= C6H5
Scheme 2.

M.C. Ortega-Alfaro et al. / Journal of Organometallic Chemistry 689 (2004) 885–893
887
The structure of 4 (Fig. 1) was established by X-ray
diffraction analysis as a second (monoclinic) polymorph
of the structure reported by Hughes et al. [14]. This
simpler polymorph has Z0 ¼ 1 in P21=n showing no
differences in the geometrical parameters0with respect to
m=z ¼ 504, which correspond to the molecular weight of
a reduced dinuclear species containing five metal car-
bonyl groups. Interestingly, the complex 5 could explain
the formation of 4, however, this intermediate 5 was not
detected in the previous reactions. This fact evidences
1
ꢁ
those found in the P1 polymorph with Z ¼ 2 (Table 1).
the well-known reductive capacity of Fe2(CO)9[15]. H
It is important to mention that the reaction of 2c with
Fe2(CO)9 under identical conditions led to the forma-
tion of complexes 3c, 4 and 5 (Scheme 3). The IR
spectrum of 3c and 5, shows M–CO absorption bands in
the range 2081–1961 cmꢀ1. The Mass spectrometry
spectrum of 3c displayed a peak m=z ¼ 492 corre-
sponding to the fragment [Mþ ) 2CO] and peaks for
successive loss of four CO ligands indicating that com-
plex 3c possesses a similar structure to those of 3a and
3b. On the other hand, complex 5 exhibits the peak
NMR data show a singlet at 8.12 and 7.45 ppm for
vinylic proton of 3c and 5, respectively, which are
slightly shifted to high frequency with respect to free
ligand. This behavior is also observed in 13C-NMR
spectra for OSCH2, CFeSO and CHCFeSO. The struc-
tures of 3a and 3c and 5 were confirmed by X-ray dif-
fraction analysis. Compounds 3a and 3c (Figs. 2 and 3)
clearly show that insertion of the diiron moiety into
the sulfanyl C–S bond of the ligand occurs specifi-
cally. Coordination around both metallic centers can be
Table 1
Crystallographic Data for Compounds 3a, 3c, 4, 5 and 6
3a
3c
4
6
5
Formula
C12H8Fe2O8S2
456.00
C18H12Fe2O9S2
548.10
C8H4Fe2O6S2
371.93
C8H6Fe2O6S2
373.95
C17H12Fe2O7S2
504.09
Formula weight (g molꢀ1
Crystal size (mm)
Color
)
0.42 ꢂ 0.28 ꢂ 0.07 0.308 ꢂ 0.078 ꢂ 0.044 0.338 ꢂ 0.134 ꢂ .024 0.276 ꢂ 0.192 ꢂ 0. 136 0.358 ꢂ 0.098 ꢂ 0.022
Red
Monoclinic
Orange
Monoclinic
P21=n
14.339(2)
8.490(1)
18.065(2)
90
Red
Monoclinic
Red
Triclinic
Deep red
Monoclinic
P21=n
12.620(1)
11.238(1)
14.575(1)
90
Crystal system
Space group
ꢁ
P21=c
P21=n
P1
ꢂ
a (A)
12.758(2)
9.206 (1)
15.346(3)
90
8.979(1)
15.751 (1)
9.537(1)
90
8.1027(4)
11.892(1)
14.249(1)
87.783(1)
77.809(1)
81.968(1)
1328.8(2)
4
ꢂ
b (A)
ꢂ
c (A)
a (°)
b (°)
c (°)
107.74(1)
90
99.160(2)
90
101.633(2)
90
110.968(2)
90
3
ꢂ
V (A )
1716.7(5)
4
1.764
2171.2(5)
4
1.677
1321.1(2)
4
1.870
1930.2(3)
4
1.735
Z
Dcalc (g cm3)
No. of collected reflections
1.869
15,862
4688(0.0440)
2960
No. of independent reflections 2821(0.0493)
24,547
3843(0.173)
10,696
2323(0.0744)
22,219
3403(0.1113)
ðRint
Þ
No. of observed reflections
Absorption correction
method
2821
Psi-scans
3843
Face-indexed
2323
Face-indexed
4688
Face-indexed
3403
Face-indexed
Max. and min. transmission
No. of parameters
Ra
Rw
GoF
0.966 and 0.612
218
0.048
0.965 and 0.801
281
0.055
0.970 and 0.762
163
0.052
0.854 and 0.743
329
0.030
0.961 and 0.581
254
0.062
b
0.101
1.017
0.098
1.018
0.096
0.981
0.048
0.986
0.076
1.004
P
P
a R ¼ jjFojjFcj= jFoj.
P
P
2
1=2
b
2
RwðFoÞ ¼ ½ wðFo2 ꢀ Fc2Þ = wFo4ꢃ
.
OC
CO
CO
O
CO
CO
OC
S
Fe
S
CO
S
Fe
S
O
S
O
Fe
Fe
Fe2(CO)9
THF
S
S
CO
+
OC
+
R
S
(OC)3
Fe
Fe(CO)3
R
CO
R
CO
4
O
O
2c R= p-OCH3-C6H5
3c R= p-OCH3-C6H5
5 R= p-OCH3-C6H5
Scheme 3.

888
M.C. Ortega-Alfaro et al. / Journal of Organometallic Chemistry 689 (2004) 885–893
Table 2
ꢂ
Selected bond lengths (A) and angles (°) for 3a
Bond lengths
Fe(1)–Fe(2)
Fe(1)–S(1)
Fe(1)–S(2)
Fe(2)–S(2)
Fe(1)–C(1)
Fe(1)–C(2)
Fe(1)–C(3)
Fe(2)–C(4)
S(1) ꢄ ꢄ ꢄ S(2)
2.626(1)
2.183(2)
2.245(2)
2.260(2)
1.812(8)
1.820(8)
1.806(8)
1.810(7)
2.925(1)
Fe(2)–C(5)
Fe(2)–C(6)
S(1)– C(12)
S(2)–C(11)
C(11)–C(12)
C(9)–C(10)
S(1)–O(7)
1.805(8)
1.784(7)
1.800(7)
1.845(7)
1.516(10)
1.353(8)
1.468(5)
2.004(6)
Fe(2)–C(10)
Bond angles
C(1)–Fe(1)–C(2)
C(3)–Fe(1)–C(1)
C(1)–Fe(1)–S(1)
C(3)–Fe(1)–S(2)
C(2)–Fe(1)–Fe(2)
S(2)–Fe(1)–Fe(2)
C(6)–Fe(2)–C(4)
C(6)–Fe(2)–C(10)
C(4)–Fe(2)–C(10)
93.4 (4)
91.1(3)
172.9(3)
146.8(2)
161.8(3)
54.6(5)
91.0(3)
86.4(3)
174.6(3)
C(5)–Fe(2)–S(2)
C(10)–Fe(2)–S(2)
C(5)–Fe(2)–Fe(1)
C(10)–Fe(2)–Fe(1)
C(9)–C(10)–Fe(2)
S(1)–Fe(1)–Fe(2)
S(1)–Fe(1)–S(2)
O(7)–S(1)–C(12)
101.7(2)
93.8(2)
152.1(2)
79.9(2)
140.8(5)
76.0(5)
82.7(7)
103.1(3)
Fig. 2. ORTEP drawing of complex 3a. Thermal ellipsoids at 30%
probability level.
display a s-syn, s-syn conformation with considerable
deviation from planarity (Tables 1–3).
described as distorted octahedrons, with the l2-S atom
and the second iron atom occupying two of the equa-
torial positions, while the sulfinyl S-atom occupies the
apical position in one case and the C-atom of the ylidene
moiety in the other. Although the bimetallic core share
many features with the structure of (l2-ethanesulfena-
tothiolato-S,S0)-bis(tricarbonyl)-iron reported by Mess-
elhauser et al. [16], the moiety is less rigid, having
iron-iron bond lengths and S ꢄ ꢄ ꢄ S interactions longer by
The compound 5 (Fig. 4) is totally analogous to
[4-phenyl-1-(1,3-dithiolane-2-ylidene)-3E-butene-2-one]
Fe2(CO)5, previously reported, [7] showing a nearly
symmetrical l-S and totally asymmetrical l-C nature of
the ligand towards the binuclear iron, as well as the r-O
and r-S coordination as the most salient features of the
structure (Tables 1 and 4).
When sulfoxide 2d was reacted with Fe2(CO)9 under
the aforementioned conditions (Scheme 4) complexes 3d
and 6 were obtained. The IR spectrum of 3d displays
bands at 2101, 2039, and 2002 cmꢀ1 for M–CO. The 1H
NMR data of 3d showed signals at 2.25 and 2.76 ppm
for methyl groups attached to the sulfur atom which are
shifted to higher frequencies with respect to the free li-
gand. The 13C NMR displays a similar shift towards
ꢂ
ca. 0.1 and 0.2 A, respectively. A considerable deviation
from the perfect C2v symmetry was also observed which
cause that the perfect eclipsed bridging methylenes in the
MesselhauserÕs structure now display a conformation
intermediate between eclipsed and gauge conformations
(angles S–CH2–CH2–S: 27.5° for 3a and 25.1° for 3c).
On both cases the 3-oxo-propen-1-en-1-sulfinyl moiety
Fig. 3. ORTEP drawing of complex 3c. Thermal ellipsoids at 30% probability level.

M.C. Ortega-Alfaro et al. / Journal of Organometallic Chemistry 689 (2004) 885–893
889
Table 3
Table 4
ꢂ
ꢂ
Selected bond lengths (AÞ and angles (°) for 3c
Bond lengths
Selected bond lengths (AÞ and angles (°) for 5
Bond lengths
Fe(1)–Fe(2)
Fe(1)–S(2)
Fe(2)–S(1)
Fe(2)–S(2)
Fe(1)–C(1)
Fe(1)–C(15)
Fe(1)–C(14)
Fe(1)–C(13)
S(1) ꢄ ꢄ ꢄ S(2)
2.642(1)
2.252(2)
2.198(1)
2.235(2)
1.993(4)
1.813(6)
1.784(6)
1.796(7)
2.929(1)
Fe(2)–C(16)
Fe(2)–C(17)
F2(2)–C(18)
S(1)– C(11)
S(2)–C(12)
C(11)–C(12)
C(1)–C(2)
1.804(7)
1.797(7)
1.797(6)
1.795(5)
1.832(5)
1.522(7)
1.359(6)
1.473(3)
Fe(1)–Fe(2)
Fe(1)–S(2)
Fe(2)–S(1)
Fe(2)–S(2)
Fe(1)–C(1)
Fe(1)–C(15)
Fe(1)–C(14)
Fe(1)–C(13)
Fe(2)–C(16)
2.624(1)
2.251(2)
2.326(2)
2.212(2)
2.265(5)
1.796(7)
1.763(7)
1.780(8)
1.802(6)
Fe(2)–C(17)
Fe(2)–O(1)
Fe(2)–C(1)
S(1)–C(1)
1.737(6)
1.946(3)
1.910(5)
1.752(5)
1.819(5)
1.800(5)
1.309(5)
1.413(6)
1.373(6)
S(1)–C(11)
S(2)–C(12)
O(1)–C(3)
C(1)–C(2)
C(2)–C(3)
S(1)–O(2)
Bond angles
Bond angles
C(14)–Fe(1)–C(13) 100.8(2)
C(14)–Fe(1)–C(15) 93.9(2)
C(13)–Fe(1)–C(15) 91.5(2)
C(17)–Fe(2)–C(16) 103.3(3)
C(14)–Fe(1)–C(13) 90.6(3)
C(14)–Fe(1)–C(15) 101.3(3)
C(13)–Fe(1)–C(15) 97.0(3)
C(1)–Fe(1)–Fe(2) 45.3(1)
C(17)–Fe(2)–C(16) 99.2(3)
C(18)–Fe(2)–S(1)
C(17)–Fe(2)–S(1)
C(16)–Fe(2)–S(1)
169.4(2)
96.5(2)
89.9(2)
C(1)–Fe(1)–Fe(2)
C(17)–Fe(2)–C(1)
C(16)–Fe(2)–C(1)
C(17)–Fe(2)–O(1)
C(16)–Fe(2)–O(1)
S(1)–Fe(2)–Fe(1)
S(2)–Fe(2)–Fe(1)
C(1)–Fe(2)–S(2)
O(1)–Fe(2)–Fe(1)
O(1)–Fe(2)–S(2)
S(2)–Fe(2)–Fe(1)
45.3(1)
95.4(2)
163.9(2)
97.8(2)
90.4(2)
82.1(4)
53.3(4)
90.1(2)
106.5(1)
159.2(1)
54.7(1)
C(14)–Fe(1)–C(1)
C(14)–Fe(1)–C(1)
C(15)–Fe(1)–C(1)
C(14)–Fe(1)–S(2)
C(13)–Fe(1)–S(2)
C(1)–Fe(1)–S(2)
C(15)–Fe(1)–S(2)
91.8(2)
85.4(2)
173.9(2)
101.7(2)
157.5(2)
91.7(2)
89.2(2)
C(15)–Fe(1)–S(1)
C(14)–Fe(1)–C(1)
C(13)–Fe(1)–C(1)
C(14)–Fe(1)–S(2)
C(15)–Fe(1)–S(2)
C(1)–Fe(1)–S(2)
C(13)–Fe(1)–S(1)
103.5(2)
110.1(2)
88.0(2)
87.5(2)
92.9(2)
83.5(1)
89.9(2)
C(18)–Fe(2)–Fe(1) 158.8(2)
C(17)–Fe(2)–Fe(1) 96.4(2)
S(1)–Fe(2)–Fe(1)
S(2)–Fe(2)–Fe(1)
O(2)–S(1)–C(1)
O(2)–S(1)–C(11)
C(1)–S(1)–C(11)
O(2)–S(1)–Fe(2)
C(1)–S(1)–Fe(2)
75.5(4)
54.2(4)
115.7(2)
108.8(2)
101.2(2)
124.3(2)
98.4(2)
C(14)–Fe(1)–Fe(2) 53.6(4)
C(18)–Fe(2)–C(17) 91.7(2)
C(18)–Fe(2)–C(16) 94.6(3)
C(14)–Fe(1)–Fe(2) 75.3(2)
C(13)–Fe(1)–Fe(2) 116.8(2)
C(15)–Fe(2)– Fe(2) 145.9(2)
lower frequencies for groups OSCH3 and CHCFeSO
(d ¼ 4 and 3), respectively. In the mass spectrum of 3d
appeared the ion m=z ¼ 326 which agreed with a dinu-
clear complex. Likewise, the complex 6 was also isolated
as red crystals in 20% yield [17], and then its structure
was established by X-ray diffraction. This compound
crystallized with two molecules chemically identical but
crystallographic independent showing the presence of a
Fe2S2 core in a butterfly form and possessing an ap-
proximately C2v molecular symmetry with the methyl
groups of the bridging sulfur atoms in a syn-endo posi-
tion, as can be seen from Fig. 5. The Fe–Fe bonds and
the S ꢄ ꢄ ꢄ S separations are consistent with the compara-
ble distances in related compounds (Table 6).
3. Conclusion
The noteworthy feature is the fact that the presence of
a sulfoxide group implies a different reactivity at the
formation of the dinuclear Fe(0) complex. Thus, the
reaction between the ligands 2a or 2c and Fe2(CO)9
leads to the formation of the new dinuclear complexes
3a and 3c. The X-ray diffraction study showed that both
metallic centers Fe1 and Fe2 are surrounded by three
terminal carbonyl groups whereas, the complex 5 dis-
plays a different coordination pattern. The Fe2 atom is
surrounded by two terminal carbonyl groups while Fe1
atom by three terminal carbonyl groups. The coordi-
nation of Fe2 is accomplished by a r-O bond from the
Fig. 4. ORTEP drawing of complex 5. Thermal ellipsoids at 30% probability level.

890
M.C. Ortega-Alfaro et al. / Journal of Organometallic Chemistry 689 (2004) 885–893
OC
CO
CO
CO
OC
S
Fe
S
O
S
O
Fe
Fe2(CO)9
THF
S
S
OC
+
R
S
Fe(CO)3
Fe
(OC)3
R
O
O
1d R= p-OCH3-C6H5
3d R= p-OCH3-C6H5
6
Scheme 4.
Fig. 5. ORTEP drawing of complex 6. Thermal ellipsoids at 30% probability level.
ketone oxygen atom and by a r-S bond of the dithiolane
ring. In addition, the complex 5 was found to play a role
as intermediate in the reductive reaction of sulfoxide
group and in the formation of complexes 4 and 6.
Mass measurements in FAB are performed at 10,000
resolution using electrical field scans and the polyeth-
ylene glycol ions as reference material. Melting points
were measured using a Mel-Temp II apparatus and are
uncorrected. All reagents were obtained from commer-
cial suppliers and used as received. Reactions were
performed under nitrogen atmosphere in carefully dried
glassware. THF was distilled from sodium-benzophe-
none under argon or nitrogen atmosphere. Column
chromatography was performed with Merck silica gel
(70–230 mesh) using ethyl acetate:hexane in different
ratios as eluent.
4. Experimental
4.1. General methods
1H NMR and 13C NMR spectra were recorded on a
JEOL 300 spectrometer, using CDCl3 as solvent and
TMS as internal reference. IR spectra were performed
on a Perkin–Elmer 283 B or 1420 spectrometer. The
FAB spectra were obtained on a JEOL JMS SX 102A
mass spectrometer operated at an accelerating voltage of
10 kV. Samples were desorbed from a nitrobenzyl al-
cohol matrix using a 6 keV Xenon atoms. The electronic
impact (EI) ionization mass spectra were acquired on a
JEOL JMS-AX505 HA Mass spectrometer operated in
the positive ion mode. The acquisition conditions were
ion source temperature 230 °C, ionization energy 70 eV,
emission current 0.14 lA and ionization current 100 lA.
4.2. Synthesis of ligands
A solution of 1-(1,3-dithiolane-2-yliden) acetone de-
rivatives [9] (0.005 mol) or 1,1-dimethylmercapto-3(4-
methoxyphenyl)-1-propen-3-one [10] in methanol with
sodium periodate (0.007 mol) was stirred for 72 h at
room temperature. The solvent was evaporated, then,
AcOEt and water (3 ꢂ 40 ml) were also added, extract-
ing the organic phase, drying with Na2SO4 and remov-
ing the volatile in vacuo. The reaction mixture was

M.C. Ortega-Alfaro et al. / Journal of Organometallic Chemistry 689 (2004) 885–893
891
purified by column chromatography on alumina, using
hexane/AcOEt as eluent.
crude was filtered off through an alumina column and
the solvent was evaporated under vacuum. The reaction
mixture was chromatographed on silica gel and elution
with hexane/ethyl acetate in different ratio gave the
corresponding Fe(0) complexes. The yields were based
on the pure products isolated.
Ligand 1-(1-oxo-1,3-dithiolan-2-yliden)acetone 2a,
yellow solid, 28% yield, m.p.: 95 °C; IR mmax (CHCl3)
cmꢀ1 ¼ 1668.47 (CO); 1535.54 (C@C); 1049.48 (S@O)
1H NMR (300 MHz, CDCl3): 2.35 (s, 3H, CH3); 3.23
(m, 2H, CH2CS); 3.70 (m, 2H, CH2CSO); 7.05 (s, 1H,
CH–CO) ppm. 13C NMR (75 MHz, CDCl3): 30.4
(CH3); 31.7 (SCH2); 52.9 (OSCH2); 121.5 (HCCSSO);
164.08 (CSSO); 195.2 (CO) ppm. MS-EI (70 eV) m=z
(%): 176 (Mþ)(30), 43(100).
Complex 3,3,3,7,7,7-hexacarbonyl-1-oxo-2-(2-oxo-pro-
pyliden)-3,7-diferra-1,4-dithiatricycle[2.2.1.13;4]heptane
3a as red crystals, 14% yield, m.p.: 83 °C; IR mmax (sol.
1
CHCl3)cmꢀ1: 2022, 2047, 2084 (M–CO). H NMR (300
MHz, CDCl3): 2.34 (s, 3H, CH3); 3.58–2.62 (m, 4H,
SCH2CH2Fe); 7.35 (s, 1H, CHCFeSO); ppm. 13C NMR
(75 MHz, CDCl3): 26.9 (FeSCH2); 29.9 (CH3); 32.9
(OSCH2); 135.4 (CHCFeSO); 167.9 (CFeSO); 190.8
(CO); 206.6 (M ) CO) ppm MS-EI (70 eV) m=z (%): 428
(Mþ ) CO)(20); 400 (Mþ ) 2CO)(55); 372 (Mþ ) 3CO)
(25). HR-MS (FABþ) C11H8O7S2Fe2: Found, 427.8404;
Calc., 427.8412.
Ligand 1-(1-oxo-1,3-dithiolan-2-yliden)acetophenone
2b yellow solid, 39% yield, m.p.: 133–135 °C; IR mmax
(CHCl3) cmꢀ1 ¼ 1637.1 (C@O), 1529.3 (C@C), 1043.1
(S@O), 938.1 (C@C). NMR 1H (300 MHz, CDCl3): 3.11
(1H, m, CH2), 3.4 (1H, m, CH2), 3.54 (1H, s, CH2), 3.8
(1H, m, CH2), 7.4 (2H, t, J ¼ 7.7 Hz, H-m), 7.55 (1H, t,
J ¼ 7.6 Hz, H-p), 7.8 (1H, s, CHCSSO), 7.9 (2H, dd,
J ¼ 7.14, 1.38 Hz, H-o) ppm. NMR 13C (75 MHz,
CDCl3): 31.7 (SCH2), 52.9 (OSCH2), 118.2 (CHCSSO),
128.3 (CHm), 128.9 (CHo), 133.4 (CHp), 137.1 (Ci), 166.7
(CSSO), 187.6 (CO) ppm; MS-EI (70 eV) m=z (%): 238
[Mþ](18), 222(10), 194(10), 163(1), 105(100), 77(40).
Ligand 1-(1-Oxo-1,3-dithiolan-2-yliden)-p-methoxy-
acetophenone 2c yellow solid, 35% yield, m.p.: 134–135
°C; IR (sol. CHCl3) mmax: 1634.5 (C@O), 1599.8 (C@C),
1043.0 (S@O) cmꢀ1. NMR 1H (300 MHz, CDCl3): 3.08–
3.11(1H, m, CH2), 3.39–3.43 (1H, m, CH2), 3.52–3.56
(1H, m, CH2), 3.85–3.87 (1H, m, CH2), 3.86 (3H, s,
CH3), 6.95 y 7.99 (4H, AA0BB0, J ¼ 7.0 Hz, H-o, H-m),
7.78 (1H, s, CHCSSO) ppm. NMR 13C (75 MHz,
CDCl3): 31.6 (SCH2), 52.9 (OSCH2), 55.6 (CH3–O),
114.2 (CHCSSO), 118.4 (CHm), 130.1 (Ci–CO), 130.7
(CHo), 163.8 (Ci–OMe), 165.5 (CSSO), 186.1 (CO) ppm;
MS-EI (70 eV) m=z (%): 268 [Mþ](10), 252(3), 240(15),
224(4), 208(5), 192(1), 177(1), 135(100), 107(8), 92(13),
77(14).
Complex 3,3,3,7,7,7-hexacarbonyl-1-oxo-2-(2-oxo-2-
phenyletyliden)-3,7-diferra-1,4-dithiatricycle[2.2.1.13;4
]
heptane 3b as red crystals 12% yield, m.p.: 150 °C (dec.);
IR (sol. CHCl3) mmax: 2922.3 (C–H), 2084.1, 2047.9,
2022.3 (M–C@O), 1015.3 (S@O), 928.3 (C@C) cmꢀ1
.
1
NMR H (300 MHz, CDCl3): 3.21–3.28 (1H, m, CH2),
3.30–3.36 (1H, m, CH2), 3.38–3.46(1H, m, CH2), 3.61–
3.64 (1H, m, CH2), 7.44–7.49 (2H, m, H-oy H-m), 7.98
(1H, t, d, J ¼ 10.3 Hz, H7), 8.15 (1H, s, CHCFeSO)
ppm. NMR 13C (75 MHz, CDCl3): 31.56 (SCH2), 67.68
(OSCH2), 111.0 (CHCFeSO), 128.39 (CHm), 128.78
(CHo), 131.78 (CHp), 133.17 (Ci), 179.89 (CFeSO),
188.81 (CO), 205.38, 206.43, 209.45 (M–C@O) ppm.
MS-EI (70 eV) m=z (%): 490 [Mþ ) CO](5), 462(40),
434(40), 406(40), 378(35), 350(85), 322(82), 290(13),
222(12), 192(5), 176(40), 105(100), 77(62). HR-MS
(FABþ) C17H11O8S2Fe2: Found, 518.8587; Calc.,
518.8594.
Complex 2-[2-oxo-2-(p-methoxyphenyl)]etyliden-3,3,
3,7,7,7-hexacarbonyl-1-oxo-3,7-diferra-1,4-dithiatricycle
[2.2.1.13;4]heptane 3c as orange crystals 15% yield, m.p.:
142 °C (dec). IR mmax (KBr)/cmꢀ1: 2081.5, 2045, 2017.7
(M–C@O), 1173.2 (S@O). NMR 1H (300 MHz, CDCl3):
3.17–3.20 (1H, m, CH2), 3.35–3.42 (1H, m, CH2), 3.43–
3.45 (1H, m, CH2), 3.61–3.65 (1H, m, CH2), 3.86 (3H, s,
CH3), 6.93 and 7–98 (4H, AA0BB0, J ¼ 8.9 Hz, H-o, H-
m), 8.12 (1H, s, CHCFeSO) ppm. NMR 13C (75 MHz,
CDCl3):27.1 (SCH2), 55.6 (OCH3), 67.8 (OSCH2), 113.9
(CHm), 114.2 (CHCFeSO), 130.8 (CHo), 132.0 (Ci-CO),
163.7 (Ci-OMe), 178.1 (CFeSO), 187.9 (CO), 205.0,
207.26, 210.81 (M–C@O) ppm. MS-EI (70 eV) m=z (%):
492 [Mþ ) 2CO](5), 464(6), 436(5), 408(5), 380(14),
352(16), 336(3), 308(4), 284(10), 252(10), 224(7),
135(100), 107(8), 92(17), 77(20). HR-MS (FABþ)
C16H12O7S2Fe2: Found, 491.8714; Calc., 491.8723.
Complex 6,6,10,10,10-pentacarbonyl-8-(p-methoxy-
Ligand 3-methylmercapto-30-oxomethylmercapto-1-
(p-methoxyphenyl)-2-propen-1-one 2d yellow solid, 27%
yield, m.p.: 144–150 °C; IR (sol. CHCl3) mmax: 1172.1
(C@O), 1048.7 (S@O), 929.1 (C@C) cmꢀ1. NMR 1H
(300 MHz, CDCl3): 2.47 (3H, s, CH3), 2.98 (3H, s,
CH3), 3.85 (3H, s, CH3), 6.84 (1H, s, CHCSSO), 6.9 y
7.9 (4H, AA0BB0, J ¼ 8.5 Hz, H-o, H-m) ppm. NMR 13
C
(75 MHz, CDCl3): 15.8 (SCH3), 43.9 (OSCH3), 55.6
(OCH3), 114.1 (CHm), 114.4 (CHCSSO), 130.0 (Ci–CO),
130.9 (CHo), 163.8 (Ci–OMe), 178.9 (CSSO), 184.2 (CO)
ppm. MS-EI (70 eV) m=z (%): 270 [Mþ](1), 255(1), 239
(2), 207(14), 193(2), 163(0.5), 135(100), 107(9), 77(11).
4.3. Synthesis of complexes
A solution of the ligand 2a–2d (1 mmol) in anhydrous
THF (40 ml) was treated with Fe2(CO)9 (3 mmol) with
magnetic stirring at room temperature for 24 h under
inert atmosphere. After the reaction was complete, the
phenyl)-6,10-diferra-7-oxa-2,5-dithiapentacycle[4.3.0.12;5
01;10.06;10]decan-7,9-diene 5 as deep red crystals, 3%
.

892
M.C. Ortega-Alfaro et al. / Journal of Organometallic Chemistry 689 (2004) 885–893
Table 6
yield, m.p.: 108 °C (dec); IR (sol. CHCl3) mmax: 2057.9,
ꢂ
1
2018.9, 1961 (M–C@O), 1602.7 (CO) cmꢀ1. NMR H
Selected bond lengths (AÞ and angles (°) for 6
Bond lengths
(300 MHz, CDCl3): 2.05–2.25, 3.46–3.51 (3H, 1H m,
CH2-CH2), 3.82 (3H, s, CH3), 6.87 and 7.77 (4H,
AA0BB0, J ¼ 8.8 Hz, H-o, H-m), 7.45 (1H, s, CHCFeSO)
ppm. NMR 13C (75 MHz, CDCl3): 31.0 (SCH2), 36.24
(SCH2), 55.4 (CH3O), 113.7 (CHm), 118.6 (CHCFeSO),
128.7 (CHo), 129.7 (Ci–CO), 161.0 (Ci–OMe), 189.8
(CFeSO), 191.1 (CO), 211.3, 213.2 (M–C@O) ppm MS-
FABþ (70 eV) m=z (%): 505 [Mþ + 1] (13), 397 (16), 307
(30), 107 (20), 77 (19). HR-MS (FABþ) C15H12O5S2Fe2:
Found, 447.8823; Calc., 447.8825.
Fe(1)–C(3)
Fe(1)–C(2)
Fe(1)–C(1)
Fe(1)–S(7)
Fe(1)–S(8)
Fe(1)–Fe(2)
Fe(2)–C(5)
Fe(2)–C(6)
Fe(2)–C(4)
Fe(2)–S(7)
Fe(2)–S(8)
1.780(3)
1.782(4)
1.804(4)
2.262(1)
2.268(1)
2.511(1)
1.785(4)
1.792(4)
1.807(3)
2.260(1)
2.271(1)
S(7) ꢄ ꢄ ꢄ S(8)
Fe(3)–S(15)
Fe(3)–S(16)
Fe(3)–Fe(4)
Fe(4)–C(9)
Fe(4)–C(10)
Fe(4)–C(11)
Fe(4)–S(16)
Fe(4)–S(15)
S(15) ꢄ ꢄ ꢄ S(16)
2.744(1)
2.266(1)
2.269(1)
2.522(1)
1.777(3)
1.784(3)
1.814(3)
2.259(1)
2.266(1)
2.773(1)
Complex 4-[2-oxo-2-(p-methoxyphenyl)]etyliden-2,2,
2,3,3,3-hexacarbonyl-1-methyl-3-methylmercapto-1-oxo-
2,3-diferra-1-thiacyclebutane 3d as red oil 12% yield; IR
(CHCl3) mmax: 3003.9 (C–H), 2101.3, 2039, 2002.3 (M–
C@O), 1599.8 (CO), 1026.3 (S@O), cmꢀ1. NMR 1H (300
MHz, CDCl3): 2.25 (3H, s, CH3), 2.76 (3H, s, CH3), 3.86
(3H, s, CH3), 7.29 (1H, s, CHCFeSO), 6.95 and 7.94 (4H,
J ¼ 7.9 Hz, AA0BB0) ppm. NMR 13C (75 MHz, CDCl3):
15.0 (SCH3), 47.7 (OSCH3), 55.6 (OCH3), 113.8 (CHm),
117.6 (CHCFeSO), 129.9 (Ci–CO), 130.6 (CHo), 163.7
(Ci–OMe), 186.0 (CFeSO), 194.4 (CO), 202.2, 205.4,
207.5 (M–C@O) ppm. MS-EI (70 eV) m=z (%): 326
[Mþ ) Fe(CO)6] (9), 254(8), 239(17), 193(70), 135(100),
105(10), 77(20). HR-MS (FABþ) C12H14O3S2Fe: Found,
325.9720; Calc., 325.9734.
Bond angles
S(7)–Fe(1)–S(8)
S(7)–Fe(1)–Fe(2)
S(8)–Fe(1)–Fe(2)
S(7)–Fe(2)–S(8)
S(7)–Fe(2)–Fe(1)
S(8)–Fe(2)–Fe(1)
Fe(2)–S(7)–Fe(1)
Fe(1)–S(8)–Fe(2)
74.56(3)
56.24(2)
56.48(2)
74.53(3)
56.31(2)
56.36(2)
67.45(3)
67.16(3)
S(15)–Fe(3)–S(16)
S(15)–Fe(3)–Fe(4)
S(16)–Fe(3)–Fe(4)
S(16)–Fe(4)–S(15)
S(16)–Fe(4)–Fe(3)
S(15)–Fe(4)–Fe(3)
Fe(4)–S(15)–Fe(3)
Fe(4)–S(16)–Fe(3)
75.40(3)
56.18(2)
55.96(2)
75.60(3)
56.34(2)
56.19(2)
67.63(3)
67.70(3)
refined by full-matrix least squares on F 2 using all data
with the all non-hydrogen atoms assigned anisotropic
displacement parameters and hydrogen atoms bound to
carbon atoms inserted at calculated position with iso-
tropic temperature factor 1.2 times the Uiso of the parent
carbon atom. The program used in the final refinements
was SHELXL 97 [19]. Selected bond lengths and bond
angles are shown in Tables 2–6.
4.4. X-ray crystal structure determinations of compounds
3a, 3c, 4, 5 and 6
Data collection and refinement parameters are sum-
marized in Table 1. The diffraction data for 3a was
collected on a Siemens P4/PC diffractometer, while those
of 3c, 4, 5 and 6 were collected on a Bruker Smart Apex
CCD diffractometer with Mo Ka radiation, k ¼ 0:71063
5. Supplementary data
Crystallographic data or the structural analysis has
been deposited with the Cambridge Crystallographic
Centre CCDC No.220305 for complex 3a, No. 220306
for complex 3c, No. 220307 for complex 4, No. 220308
for complex 6 and No. 220309 for complex 5. Copies of
this information may be obtained free of charge from
The Director, 12 Union Road, Cambridge, CB2 IEZ,
UK (fax: +44 1223 336033; e-mail: deposit@ccdc.cam.
ac.uk or www: http://www.cdcc.cam.ac.uk).
ꢂ
A. Each data set was corrected for Lorentz and polari-
zation effects and empirical absorption corrections
based on psi-scans were applied. The structures were
solved by direct methods [18] and each structure was
Table 5
ꢂ
Selected bond lengths (AÞ and angles (°) for 4
Bond lengths
Acknowledgements
Fe(1)–C(1)
Fe(1)–C(3)
Fe(1)–C(2)
Fe(1)–S(1)
Fe(1)–S(2)
Fe(1)–Fe(2)
Fe(2)–C(4)
1.774(8)
1.788(8)
1.813(7)
2.236(2)
2.238(2)
2.505(2)
1.787(8)
Fe(2)–C(6)
Fe(2)–C(5)
Fe(2)–S(1)
Fe(2)–S(2)
S(1)–C(7)
S(2)–C(8)
1.800(8)
1.805(7)
2.240(2)
2.242(2)
1.806(7)
1.820(7)
We thank DGAPA for financial support (Project #
~
IN216201). The technical assistance of Rocio Patino,
Luis Velasco and Javier Perez is gratefully acknowledged.
ꢀ
References
Bond angles
S(1)–Fe(1)–S(2)
S(1)–Fe(1)–Fe(2)
S(2)–Fe(1)–Fe(2)
S(1)–Fe(2)–S(2)
80.54(7)
56.03(5)
56.08(5)
80.39(7)
S(1)–Fe(2)–Fe(1)
S(2)–Fe(2)–Fe(1)
Fe(1)–S(1)–Fe(2)
Fe(1)–S(2)–Fe(2)
55.91(5)
55.93(5)
68.06(6)
67.99(5)
[1] C. Alvarez-Toledano, A.C. Cano, R.A. Toscano, A. Parlier, H.
Rudler, Bull. Soc. Chim. Fr. 130 (1993) 601.
[2] N.W. Alcock, C.J. Richards, S.E. Thomas, Organometallics 10
(1991) 231.

M.C. Ortega-Alfaro et al. / Journal of Organometallic Chemistry 689 (2004) 885–893
893
[3] T.A. Mitsudo, H. Watanabe, T. Sasaki, Y. Takegami, Y.
Watanabe, K. Kafuku, K. Nakatsu, Organometallics 8 (1989)
368, and references cited therein.
[11] (a) P. Sykes, A.R. Todd, Committee on Penicillin Synthesis
Report 526, 677;
(b) N.J. Leonard, C.R. Johnson, J. Org. Chem. 27 (1962) 282.
[12] P. Yates, T.R. Lunch, D.R. Moore, Can. J. Chem. 49 (1971) 1467.
[13] A. Shawer, P.J. Fitzpatrick, K. Steliow, I.S. Butter, J. Am. Chem.
Soc. 101 (1979) 1313.
[4] J. Klimes, E. Weiss, Angew. Chem. Int. Ed. Engl. 21 (1982) 205.
ꢀ
[5] C. Alvarez, R. Gutierrez, R.A. Toscano, M. Moya, L. Velasco, R.
Rosas, R. Tapia, G. Penieres, J. Coord. Chem. 48 (1999) 383.
ꢀ
[6] C. Alvarez-Toledano, J. Enrıquez, R.A. Toscano, M. Martınez-
Garcıa, E. Cortes-Cortes, Y. Osornio, O. Garcıa, R. Gutierrez-
ꢀ
[14] (a) D.L. Hughes, G.L. Leigh, D.R. Paulson, Inorg. Chim. Acta
120 (1986) 191;
(b) F. Dahl, C.H. Suan, Inorg. Chem. 4 (1965) 1.
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
Perez, J. Organomet. Chem. 577 (1999) 38.
ꢀ
ꢀ
ꢀ
[7] F. Ortega-Jimenez, M.C. Ortega-Alfaro, J.G. Lopez-Cortes, R.
~
[15] D.F. Shriver, K.H. Whitmire, Comprehensive Organometallic
Chemistry, in: G. Wilkinson, F.G. Stone, E.W. Abel (Eds.), The
Synthesis, Reactions and Structures of Organometallic Com-
pounds, vol. 4, Pergamon Press, Oxford, 1982, pp. 251–252.
[16] J. Messelhauser, K.U. Gutensohn, I.P. Lorenz, W. Hiler, J.
Organomet. Chem. 321 (1987) 377.
ꢀ
ꢀ
Gutierrez-Perez, R.A. Toscano, L. Velasco-Ibarra, E. Pena-
Cabrera, C. Alvarez-Toledano, Organometallics 19 (2000) 4127.
ꢀ
ꢀ
[8] C. Alvarez-Toledano, R. Gutierrez-Perez, R.A. Toscano, M.
Moya-Cabrera, T. Haquet, M.C. Ortega, A. Cabrera, Polyhedron
20 (2002) 215.
ꢀ
[9] (a) A. Thullier, J. Vialle, Bull. Soc. Chim. Fr. (1959) 1398;
[17] L.F. Dahl, C.H. Wei, Inorg. Chem. 2 (1963) 328.
[18] A. Altomare, G. Cascarano, C. Giacovazzo, A. Guagliardi, M.C.
Burla, G. Polidori, M. Canalli, J. Appl. Cryst. 27 (1994) 435.
[19] G.M. Sheldrick, SHELXL 97 Program for refinement of crystal
structures, University of Goettingen, Germany.
(b) F.C.V. Larsson, S.O. Lawesson, Tetrahedron 28 (1972) 5341.
[10] (a) I. Shahak, Y. Sasson, Tetrahedron Lett. (1973) 4207;
(b) K.T. Potts, M.J. Cipullo, P. Ralli, G. Theodoridis, J. Org.
Chem. 47 (1982) 3027.