Synthesis of double and multiple butterfly.

Article abstract of DOI:10.1016/S0022-328X(00)00548-9

The [Et₃NH]⁺ salts of μ-CO anions [(μ-RE)(μ-CO)Fe₂(CO)₆]^- (E=S, Se) prepared from Fe₃(CO)₁₂, REH (R=S,Se) and Et₃N reacted with μ-S₂Fe₂(CO)₆ and subsequent treatment of the intermediate [Et₃NH]⁺ salts of S-centered anions (μ-RE)(μ-S^-)[Fe₂(CO)₆]₂(μ₄-S) with MeI, PhCH₂Br, p-(BrCH₂)₂C₆H₄ or 1,3,5-(BrCH₂)₃C₆H₃ to give a series of μ₄-S-containing double and multiple butterfly clusters (μ-RE)(μ-MeS)[Fe₂(CO)₆]₂(μ₄-S) (7-9, RE=t-BuS, PhSe, p-MeC₆H₄Se), (μ-p-MeC₆H₄Se)(μ-PhCH₂S)[Fe₂(CO)₆]₂(μ₄-S) (11), {(μ-t-BuS)[Fe₂ (CO)₆]₂(μ₄-S)}₂[(μ-p-(SCH₂)₂C₆H₄] (12) and {(μ-t-BuS)[Fe₂(CO)₆]₂(μ₄-S)}₃[μ-1,3,5-(SCH₂)₃C₆H₃] (13), whereas the [MgBr]⁺ salts of μ-CO anions [(μ-RTe)(μ-CO)Fe₂(CO)₆]^- prepared from Grignard reagents RMgBr and elemental Te followed by treatment of the intermediates RTeMgBr with Fe₃(CO)₁₂, reacted with S₂Cl₂ to afford a series of RTe-containing and μ-S-S-μ bridged double butterfly clusters [(μ-RTe) Fe₂(CO)₆]₂(μ-S-S-μ) (14-17, R=Et, i-Bu, Ph, p-MeC₆H₄). Similarly, the RTe- and μ₄-S-containing double butterfly cluster (μ-p-MeC₆H₄Te)(μ-MeS)[Fe₂(CO)₆]₂(μ₄-S) (10) could be prepared by reaction of the [MgBr]⁺ salt of μ-CO anion (μ-p-MeC₆H₄Te)(μ-CO)Fe₂(CO)₆]^- with μ-S₂Fe₂(CO)₆ followed by treatment with MeI. All these new clusters 7-17 have been characterized by combustion analysis, IR, ¹H-NMR, ⁷⁷Se-NMR and ¹²⁵Te-NMR spectroscopies, as well as by X-ray diffraction analyses for 9 (RE=p-MeC₆H₄Se) and 12 (RE=t-BuS).

Full text of DOI:10.1016/S0022-328X(00)00548-9

Journal of Organometallic Chemistry 623 (2001) 56–64
www.elsevier.nl/locate/jorganchem
Synthesis of double and multiple butterfly Fe/E (E=S, Se, Te)
cluster complexes via reactions of complex anions
[(m-RE)(m-CO)Fe2(CO)6]− (E=S, Se, Te). Crystal structures of
(m-p-MeC6H4Se)(m-MeS)[Fe2(CO)6]2(m4-S) and
{(m-t-BuS)[Fe2(CO)6]2(m4-S)}2[(m-p-SCH2)2C6H4]
Li-Cheng Song a,*, Guo-Liang Lu a, Qing-Mei Hu a , Jing Yang a, Jie Sun b
a Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai Uni6ersity, Tianjin 300071, PR China
b Laboratory of Organometallic Chemistry, Chinese Academy of Sciences, Shanghai 200032, PR China
Received 2 June 2000; accepted 10 August 2000
Abstract
The [Et3NH]+ salts of m-CO anions [(m-RE)(m-CO)Fe2(CO)6]− (E=S, Se) prepared from Fe3(CO)12, REH (R=S,Se) and Et3N
reacted with m-S2Fe2(CO)6 and subsequent treatment of the intermediate [Et3NH]+ salts of S-centered anions (m-RE)(m-S−
)[Fe2(CO)6]2(m4-S) with MeI, PhCH2Br, p-(BrCH2)2C6H4 or 1,3,5-(BrCH2)3C6H3 to give a series of m4-S-containing double and
multiple butterfly clusters (m-RE)(m-MeS)[Fe2(CO)6]2(m4-S) (7–9, RE=t-BuS, PhSe, p-MeC6H4Se), (m-p-MeC6H4Se)(m-
PhCH2S)[Fe2(CO)6]2(m4-S) (11), {(m-t-BuS)[Fe2 (CO)6]2(m4-S)}2[(m-p-(SCH2)2C6H4] (12) and {(m-t-BuS)[Fe2(CO)6]2(m4-S)}3[m-1,3,5-
(SCH2)3C6H3] (13), whereas the [MgBr]+ salts of m-CO anions [(m-RTe)(m-CO)Fe2(CO)6]− prepared from Grignard reagents
RMgBr and elemental Te followed by treatment of the intermediates RTeMgBr with Fe3(CO)12, reacted with S2Cl2 to afford a
series of RTe-containing and m-S–S-m bridged double butterfly clusters [(m-RTe) Fe2(CO)6]2(m-S–S-m) (14–17, R=Et, i-Bu, Ph,
p-MeC6H4). Similarly, the RTe- and m4-S-containing double butterfly cluster (m-p-MeC6H4Te)(m-MeS)[Fe2(CO)6]2(m4-S) (10) could
be prepared by reaction of the [MgBr]+ salt of m-CO anion (m-p-MeC6H4Te)(m-CO)Fe2(CO)6]− with m-S2Fe2(CO)6 followed by
1
treatment with MeI. All these new clusters 7–17 have been characterized by combustion analysis, IR, H-NMR, 77Se-NMR and
125Te-NMR spectroscopies, as well as by X-ray diffraction analyses for 9 (RE=p-MeC6H4Se) and 12 (RE=t-BuS). © 2001
Elsevier Science B.V. All rights reserved.
Keywords: Sulfur; Selenium; Tellurium; Iron; CO-bridged anions; X-ray structures
1. Introduction
two major types. In one type, reactions with the elec-
trophiles containing a leaving group gave neutral prod-
ucts in which the organic or inorganic group replaced
the m-CO ligand. In the other type, reactions with the
electrophiles without a leaving group initially produced
another anions and finally afforded neutral products by
incorporating an additional electrophile. On the basis
of our previous studies related to the anions [(m-RE)(m-
CO)Fe2(CO)6]− (1-3) [3,10–23] we continued to study
the above-mentioned two types of reactions with the
electrophiles containing a perthio group, i.e. sulfur(I)
chloride S2Cl2 and dithiobis(tricarbonyliron) m-
S2Fe2(CO)6. Interestingly, these reactions investigated
have led us to obtain a series of new double and
Since the first preparations of complex anions [(m-
RE)(m-CO)Fe2(CO)6]− (1, E=S [1]; 2, E=Se [2]; 3,
E=Te [3]), their reactions have been intensively studied
and successfully utilized in the synthesis of single, dou-
ble and multiple butterfly Fe/E cluster complexes con-
taining organic and inorganic structural moieties
[1–23]. Reactions of such anions with most elec-
trophiles can be rationalized in terms of their behavior
as iron-centered nucleophiles and may be classified as
* Corresponding author. Fax: +86-22-2350-4853.
E-mail address: lcsong@public.tpt.tj.cn (L.-C. Song).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(00)00548-9

L.-C. Song et al. / Journal of Organometallic Chemistry 623 (2001) 56–64
57
multiple butterfly Fe/E (E=S, Se, Te) cluster com-
plexes. Herein we report their syntheses and spectro-
scopic characterization, as well as the crystal structures
of two representative cluster complexes.
that although the intermediate anions 4–6 could not be
isolated and directly characterized due to their very
unstable nature, the suggested formation of 4–6
(Scheme 1) is reasonable in terms of the well-known
reductive cleavage of the S–S bond in m-S2Fe2(CO)6
under the action of nucleophiles [22]. In addition, their
existence has been indirectly proved by the full charac-
terization of their derivatives 7–13 (Scheme 1) obtained
via in situ alkylations of 4–6 by alkyl halides [22].
For the preparations of these double and multiple
butterfly clusters, the following points should be men-
tioned. (i) Anions 1 (RE=t-BuS) and 2 (RE=PhSe,
p-MeC6H4Se) were prepared as their [Et3NH]+ salts
from Fe3(CO)12, REH (RE=t-BuS, PhSe, p-
MeC6H4Se) and Et3N [1–16], whereas anion 3 (RE=p-
MeC6H4Te) as its [MgBr]+ salt was prepared by an
insertion reaction of elemental Te with Grignard
reagent p-MeC6H4MgBr followed by treatment of the
intermediate p-MeC6H4TeMgBr with Fe3(CO)12 [20].
(ii) Alkyl halides could be added when S-centered an-
ions 4–6 were completely formed or they were added
with m-S2Fe2(CO)6 together since they could not react
with either Fe-centered anions 1–3 or m-S2Fe2(CO)6
between −78°C and room temperature. (iii) The yields
of products with E=S (7, 12, 13) are greater than those
of products with E=Se (8, 9, 11) and in turn greater
than the yield of product with E=Te (10). Such an
order is consistent with the order of the decreased
2. Results and discussion
2.1. Reactions of [(v-RE)(v-CO)Fe2(CO)6]− (1–3) with
v-S2Fe2(CO)6/alkyl halides leading to (v-RE)(v-MeS)-
[Fe2(CO)6]2(v4-S) (7–10; RE=t-BuS, PhSe,
p-MeC6H4Se, p-MeC6H4Te), (v-p-MeC6H4Se)-
(v-PhCH2S)[Fe2(CO)6]2(v4-S) (11), {(v-t-BuS)-
[Fe2 (CO)6]2(v4-S)}2[(v-p-(SCH2)2C6H4] (12) and
{(v-t-BuS)[Fe2(CO)6]2(v4-S)}3[v-1,3,5-(SCH2)3C6H3]
(13)
Interestingly, we found that the Fe-centered anions
(m-RE)(m-CO)Fe2(CO)6]− (1–3) could react with
m-S2Fe2(CO)6, via nucleophilic attack of the negatively
charged Fe atom of 1–3 at the S atom of m-S2Fe2(CO)6
followed by loss of the m-CO ligand through coordina-
tion of the m3-S atom to another Fe atom in intermedi-
ates m, to give corresponding sulfur-centered anions
(4–6, E=S, Se, Te) (Scheme 1). More interestingly,
these anions 4–6 were found to be able to further react
with alkyl mono-, di- and trihalides, giving a series of
double and multiple butterfly Fe/E (E=S, Se, Te)
cluster complexes 7–13 (Scheme 1). It is worth noting
Scheme 1.

58
L.-C. Song et al. / Journal of Organometallic Chemistry 623 (2001) 56–64
could react with S2Cl2 to give double clusters [(m-RE)
Fe2(CO)6]2 (m-S–S-m) (E=S, Se). In order to systemat-
ically develop the chemistry of anions 1–3, we further
studied this type of reactions by using anions 3 (E=Te)
to see if similar results could be obtained. In fact, it was
found that anions 3 (R=Et, i-Bu, Ph, p-MeC6H4) as
their [MgBr]+ salts, prepared by an insertion reaction
of elemental Te with Grignard reagents RMgBr fol-
lowed by treatment of the intermediates RTeMgBr with
Fe3(CO)12 [20], were indeed reacted with S2Cl2 under
similar conditions to give a series of corresponding
RTe-containing double butterfly clusters 14–17
(Scheme 2).
It follows that anion 3, as compared with anions 1
and 2, shows similar chemical behavior towards elec-
trophile S2Cl2. Apparently, double clusters 14–17, just
like their S/Se analogs [12] might be rationalized as
produced via intermediates n formed by nucleophilic
attack of the negatively charged Fe atom in 3 at two S
atoms in S2Cl2, followed by the intramolecular displace-
ment of two m-CO ligands by the S–S moiety in n
(Scheme 2).
Scheme 2.
nucleophilicity of the anions 1\2\3 and is also in
good agreement with the increased decomposition trend
of the anions 1B2B3 [3,12,13,16]. (iv) The corre-
sponding single butterfly clusters (m-RE)2Fe2(CO)6
(RE=t-BuS, PhSe, p-MeC6H4Se, p-MeC6H4Te) were
always produced along with products 7–13. These sin-
gle clusters are believed to be formed by decomposition
of anions 1–3 to give fragments (m-RE)Fe(CO)3 fol-
lowed by their dimerization [3,12,13,16].
It is noteworthy that while products 7 and 9 were
reported preliminarily in our communication [22] in
connection with the study of the formation and reac-
tions of novel anions 4 (E=S) and 5 (E=Se), products
8 and 10–13 prepared from anions 4–6 have never
been reported so far. All the clusters 7–13 were charac-
It is worth noting that in the preparations of 14–17
the corresponding single clusters of type (m-
RE)2Fe2(CO)6 (E=Te) were also yielded along with
double clusters 14–17. In fact, single clusters of type
(m-RE)2Fe2(CO)6 (E=S, Se, Te) were often observed as
by-products in other reactions involved anions 1–3
[2,12,13,16]. In the reactions of 3·[MgBr]+ with S2Cl2,
14–17 were produced in 11%–14% yields along with
(m-RTe)2Fe2(CO)6 (R=Et, i-Bu, Ph p-MeC6H4) in
17%–44% yields. The quite high yields for (m-
RTe)2Fe2(CO)6 are apparently due to serious decompo-
sition of anion 3 to give fragments (m-RTe)Fe(CO)3 and
subsequent dimerization [3,12,13,16].
1
terized by elemental analysis, IR, H-NMR and 77Se-
NMR spectroscopies. For example, the 1H-NMR
spectra of double clusters 7–10 showed one singlet at
1.44 and 2.14–2.17 ppm for their t-Bu and Me groups
bonded to bridged S atoms, whereas the 77Se-NMR
spectra of double clusters 8, 9, 11 displayed one singlet
at 249.63, 248.04 or 249.52 ppm for their bridged Se
1
atoms in RE groups. Furthermore, the H-NMR spec-
While these single clusters (m-RTe)2Fe2(CO)6(R=Et,
i-Bu, Ph, p-MeC6H4) are known [3,20], clusters 14–17
are the first S–S bonded double Fe2STe butterfly clus-
ters, which have been characterized by combustion
tra of multiple clusters 12 and 13 also showed one
singlet at 1.42 or 1.43 ppm for their t-Bu groups
attached to bridged S atoms, whereas the 1H-NMR
spectrum of 12 displayed only one quartet of AB
pattern for its CH2 groups bound to bridged S atoms.
Obviously, such NMR spectral patterns for clusters
7–13 are completely consistent with the fact that Fe/E
clusters containing a m4-S or m4-Se atom with a general
formula [(m-RE) Fe2(CO)6]2(m4-S) or (m4-Se) could exist,
on the basis of the steric repulsion grounds, as only one
isomer in which the two substituents R are bonded to
the bridged E (E=S, Se, Te) atoms with an equatorial
type of bond [16,18,24,26].
1
analysis, IR, H-NMR and 125Te-NMR spectroscopies.
It should be pointed out that although double clusters
of [(m-RE)Fe2(CO)6]2(m-S–S-m)(E=S, Se, Te) may have
ten conformers, namely i(aeea), ii(aeee), iii(eeee),
iv(eaea), v(eaee), vi(eaae), vii(aaaa), viii(aaae), ix(aaee)
and x(aaea), according to the axial and/or equatorial
orientations of the S–S and R–E bonds to the butterfly
Fe2SE subcluster core [12], only six conformers of
i(aeea)–vi(eaae) could actually exist since conformers
of vii(aaaa)–x(aaea) all involve the strong steric repul-
sions between two axially bonded R and subcluster core
(m-RE)(m-S)Fe2(CO)6 [25,26]. In fact, double clusters
2.2. Reactions of [(v-RTe)(v-CO)Fe2(CO)6]− (3) with
S2Cl2 leading to [(v-RTe)Fe2(CO)6]2(v-S–S-v) (14–17;
R=Et, i-Bu, Ph, p-MeC6H4)
1
14–17 have proved by H-NMR and 125Te-NMR spec-
troscopies to be present as only one of the three con-
formers i(aeea), iii(eeee) or vi(eaae), as shown in
Scheme 3. This is because all these three conformers
have their two R groups and two Te atoms located in
We previously reported [12] that anions [(m-RE)(m-
CO)Fe2(CO)6]− (1, 2; E=S, Se) as their [Et3NH]+ salts

L.-C. Song et al. / Journal of Organometallic Chemistry 623 (2001) 56–64
59
Scheme 3.
1
the same chemical environment and the H-NMR spec-
tra of 14, 15 and 17 showed only one quartet at 2.76
ppm, one doublet at 2.75 ppm and one quartet of
AA%BB% pattern at 7.22 ppm, respectively, for the two
CH2 of two Et groups, two CH2 of two i-Bu groups
and two para-substituted benzene rings attached to
bridged Te atoms. In addition, it is also because that
the 125Te-NMR spectra of 14–17 each exhibited only
one signal, a singlet, respectively, at 182.52, 96.11,
309.14 or 306.17 ppm for the two bridged Te atoms
attached to R groups. However, since no comparable
1H- or 125Te-NMR spectral data are available so far for
assignment of the spatial orientations of Et, i-Bu, Ph
and para-substituted benzene groups, we cannot distin-
guish the three conformers of double clusters 14–17.
Furthermore, it should be also noted that although the
conformers for similar double clusters [(m-
PhTe)Fe2(CO)6]2(m-Te–Te-m) (conformer eaae) [3] and
[(m-PhS)Fe2(CO)6]2(m-S–S-m) (conformer aeea) [27]
were characterized by X-ray diffraction techniques, the
conformers for 14–17 have not been established by
X-ray diffractions, owing to lack of the suitable single
crystals.
this S/Se mixed cluster 9 are also very similar to corre-
sponding those of Fe4S3 and Fe4Se3 clusters, such as
[(m-MeS)Fe2(CO)6]2(m4-S) [28] and [(m-p-MeC6H4Se)-
Fe2(CO)6]2(m4-Se) [17]. More interestingly, Fig. 2 shows
that the molecule of product 12 comprises two identical
double butterfly structural units{(m-t-BuS)(m-S)[Fe2-
(CO)6]2(m4-S)}, which are bridged together by a para-
disubstituted benzene moiety p-CH2C6H4CH2-p. Simi-
lar to 9, the two substituents t-Bu and two CH2 groups
in the bridging p-CH2C6H4CH2-p group on the two
double cluster cores are bound to S3/S3* and S1/S1*
atoms by an equatorial bond and each of the three COs
bonded to Fe atom is terminal. So, this structure is also
in accordance with its spectroscopic data and the con-
former analysis. Although the quadruple Fe/S butterfly
clusters {(m-RS)[Fe2(CO)6]2(m4-S)}2(m-S–S-m)} (R=Et,
t-Bu) are known[23], to our knowledge, 12 is the first
organic group-bridged quadruple butterfly Fe/S cluster
complex prepared and crystallographically character-
ized so far. The geometrical parameters of 12 involved
in each of the four butterfly subcluster cores Fe2S2 are
very close to each other. For instance, in subcluster
core Fe1Fe2S1S2 the bond lengths and angles are Fe1–
,
,
Fe2=2.538(1) A, Fe1–S2=2.246(2) A, Fe2–S2=
,
2.3. Crystal structures of 9 and 12
2.241(2) A, Fe1–S2–Fe2=68.87(5)° and Fe1–S1–
Fe2=68.24(5)°, whereas in subcluster core Fe3Fe4S2S3
,
,
The X-ray crystal diffraction analyses have confirmed
the structures of products 9 and 12. While ORTEP plots
of 9 and 12 are shown in Figs. 1 and 2, selected bond
lengths and angles are given in Tables 1 and 2, respec-
tively. As seen from Fig. 1, product 9 is a chiral double
cluster complex which consists of the two different
butterfly subcluster cores Fe(1)Fe(2)S(1)S(2) and
Fe(3)Fe(4)S(1)Se joined to a spiro type of m4-S, i.e. the
S(1) atom. In addition, it can be seen that each of the
three COs attached to Fe atom is terminal and the two
substituents Me and p-MeC6H4 on the subcluster cores
are bonded to S(2) and Se atoms by an equatorial
bond. Therefore, this structure is consistent with its
spectroscopic data and the conformer analysis. It is
noteworthy that the corresponding bond lengths and
angles related to the two different subcluster cores are
very similar. For example, the bond length of Fe(3)–
those are Fe3–Fe4=2.523(1) A, Fe3–S2=2.244(2) A,
,
Fe4–S2=2.251(2) A, Fe3–S2–Fe4=68.31(5)° and
Fe3–S3–Fe4=67.42(5)°, respectively. In fact, these ge-
ometrical parameters are also very close to those found
in the single, double, triple and non-bridged quadruple
,
Fe(4) (2.544(2)A) and bond angle of Fe(3)–S(1)–Fe(4)
(69.60(8)°) are only slightly longer than that of Fe(1)–
,
Fe(2) (2.515(2) A) and Fe(1)–S(1)–Fe(2) (68.10(8)°),
respectively. In addition, the geometrical parameters for
Fig. 1. Molecular structure of 9 showing the atom labeling scheme.

60
L.-C. Song et al. / Journal of Organometallic Chemistry 623 (2001) 56–64
Fig. 2. Molecular structure of 12 showing the atom labeling scheme.
butterfly Fe/S cluster complexes, such as (m-
EtS)2Fe2(CO)6 [29], [(m-MeS)Fe2(CO)6]2(m4-S) [28], [(m-
PhS)Fe2(CO)6]2(m-S–S-m) [27], [(m-MeS)Fe2(CO)6]2-
(m-S–(m-CH2C6H4CH2-m)–S-m) [30], [(m-t-BuS)Fe2-
(CO)6]2(m4-S)Fe2(CO)6–S-m4] [22] and {(m-t-BuS)[Fe2-
(CO)6]2 (m4-S)}2(m-S–S-m)} [23].
ical shifts are referenced to Me2Se(l=0) and Me2Te-
(l=0), respectively. C/H analyses were performed on a
Yanaco CHN Corder MT-3 analyzer. Melting points
were determined on a Yanaco MP-500 apparatus.
Table 1
,
Selected bond lengths (A) and angles (°) for 9
Fe(1)–Fe(2)
Fe(1)–S(2)
Fe(2)–S(2)
Fe(3)–Fe(4)
Se–Fe(3)
2.515(2)
2.261(3)
2.265(3)
2.544(2)
2.391(2)
76.5(1)
Fe(1)–S(1)
Fe(2)–S(1)
Fe(3)–S(1)
Fe(4)–S(1)
Se–Fe(4)
2.247(3)
2.245(3)
2.226(3)
2.231(3)
2.397(2)
55.92(7)
3. Experimental
All reactions were carried out under an atmosphere
of highly purified nitrogen using standard Schlenk and
vacuum-line techniques. Tetrahydrofuran(THF) was
distilled under nitrogen from sodium/benzophenone
ketyl, triethylamine from potassium hydroxide. While
S2Cl2 commercially available was redistilled from sulfur
powder, tellurium powder, EtSH, t-BuSH, MeI and
PhCH2Br were commercially available and used with-
out further purification. Fe3(CO)12 [31], m-S2Fe2(CO)6
[26], PhSeH [32], p-MeC6H4SeH [32], Grignard reagents
RMgX (R=Et, i-Bu, Ph, p-MeC6H4) [33], p-
(BrCH2)2C6H4 [34] and 1,3,5-(BrCH2)3C6H3 [34] were
prepared according to the literature. The products were
separated by TLC (20×25×0.25 cm, silica gel G) and
further purified by recrystallization from mixed
CH2Cl2–hexane solvent. IR spectra were recorded on a
Nicolet 170 SX FTIR spectrophotometer. 1H-NMR
spectra were recorded on a Bruker AC-P200 NMR
spectrometer.77Se-NMR and 125Te-NMR spectra were
recorded on a UNITY plus-400 spectrometer with
Ph2Se2 and Ph2Te2 as external standards and the chem-
S(1)–Fe(1)–S(2)
S(1)–Fe(1)–Fe(2)
Fe(3)–Se–Fe(4)
S(1)–Fe(2)–S(2)
S(2)–Fe(2)–Fe(1)
S(1)–Fe(4)–Fe(3)
Fe(3)–S(1)–Fe(4)
Fe(2)–S(1)–Fe(1)
64.19(5)
76.4(1)
56.16(8)
55.12(7)
69.60(8)
68.10(8)
S(2)–Fe(1)–Fe(2)
S(1)–Fe(2)–Fe(1)
Se–Fe(3)–Fe(4)
S(1)–Fe(4)–Se
S(2)–Fe(2)–Fe(1)
Fe(1)–S(2)–Fe(2)
56.32(8)
55.98(7)
58.02(5)
77.47(8)
56.16(8)
67.52(9)
Table 2
,
Selected bond lengths (A) and angles (°) for 12
Fe(1)–Fe(2)
Fe(2)–S(1)
Fe(4)–S(3)
Fe(2)–S(2)
Fe(3)–S(3)
2.538(1)
2.255(2)
2.279(2)
2.241(2)
2.268(2)
Fe(1)–S(2)
Fe(3)–S(2)
Fe(1)–S(1)
Fe(3)–Fe(4)
Fe(4)–S(2)
2.246(2)
2.244(2)
2.269(2)
2.523(1)
2.251(2)
Fe(1)–S(1)–Fe(2)
68.24(5)
Fe(1)–S(2)–Fe(3) 134.86(7)
Fe(3)–S(2)–Fe(4) 68.31(5)
Fe(1)–S(2)–Fe(4) 124.42(6)
Fe(3)–S(3)–Fe(4) 67.42(5)
Fe(2)–S(2)–Fe(3) 137.27(7)
Fe(1)–S(2)–Fe(2) 68.87(5)
Fe(2)–S(2)–Fe(4) 134.76(7)

L.-C. Song et al. / Journal of Organometallic Chemistry 623 (2001) 56–64
61
3.1. Preparation of
instead of PhSeH. The first major band afforded 0.228
(v-t-BuS)(v-MeS))[Fe2(CO)6]2(v4-S) (7)
g (49%) of (m-p-MeC6H4Se)2Fe2(CO)6, which was iden-
1
tified by comparison of its melting point and H-NMR
A 100 ml two-necked flask equipped with a magnetic
stir-bar, a N2 inlet tube and a serum cap was charged
with 0.504 g (1.0 mmol) of Fe3(CO)12, 10 ml of THF,
0.11 ml (1.0 mmol) of t-BuSH and 0.14 ml (1.0 mmol)
of Et3N. The mixture was stirred at room temperature
(r.t.) for 0.5 h to give a yellow–brown solution. To the
solution was added 0.344 g (1.0 mmol) of m-S2Fe2(CO)6
and the mixture was stirred at r.t. for 2 h to give a
brown–green solution. To this solution was added 0.13
ml (2.0 mmol) of MeI and then the new mixture was
stirred at r.t. for an additional 12 h. The resulting
mixture was filtered and condensed under reduced pres-
sure. The residue was subjected to TLC separation
using petroleum ether as eluent. From the major red
band was obtained 0.668 g (92%) of 7 as a red solid.
M.p. 150°C (dec.). Anal. Found: C, 28.06; H, 1.67.
Calc. for C17H12Fe4O12S3: C, 28.04; H, 1.65%. IR (KBr
disk): terminal CꢀO, 2082vs, 2052vs, 2034vs, 1984s,
spectrum with those of an authentic sample [12]. The
second major band gave 0.380 g (47%) of 9 as a red
solid. M.p. 154°C (dec.). Anal. Found: C, 29.50; H,
1.66. Calc. for C20H10Fe4O12S2Se: C, 29.68; H, 1.24%.
IR (KBr disk): terminal CꢀO, 2082m, 2052s, 2032vs,
1
1993vs, 1970s cm−1. H-NMR (CDCl3): l 2.17 (s, 3H,
SCH3), 2.29 (s, 3H, ArCH3), 7.12 (q, AA%BB%, J=7.5
Hz, 4H, C6H4) ppm. 77Se-NMR (CDCl3, Me2Se): l
248.04 (s) ppm.
3.4. Preparation of
(v-p-MeC6H4Te)(v-MeS)[Fe2(CO)6]2(v4-S) (10)
A 100 ml two-necked flask equipped with a magnetic
stir-bar, a serum cap and a reflux condenser topped
with a N2 inlet tube was charged with 0.255 g (2.0
mmol) of tellurium powder, 20 ml of THF and ca. 2.0
mmol of p-MeC6H4MgBr in THF. The mixture was
stirred at reflux for 0.5 h to give a yellowish solution.
After the solution was cooled to r.t., 1.00 g (2.0 mmol)
of Fe3(CO)12 was added and the reaction mixture was
stirred for 0.5 h to produce a brown solution. The
solution was cooled to −78°C by a dry-ice–acetone
bath and then 0.344 g (1.0 mmol) of m-S2Fe2(CO)6 and
0.13 ml (2.0 mmol) of MeI were added. The new
mixture was warmed naturally to r.t. by removal of the
cooling bath and then was stirred for an additional 12
h. The resulting mixture was filtered and condensed
under reduced pressure. The residue was subjected to
TLC separation using CH2Cl2–petroleum ether (v/v,
1:10) as eluent. The first major band afforded 0.298 g
(42%) of (m-p-MeC6H4Te)2Fe2(CO)6, which was iden-
1
1979s, 1972s, 1967m cm−1. H-NMR (CDCl3): l 1.44
(s, 9H, C(CH3)3), 2.14 (s, 3H, CH3) ppm.
3.2. Preparation of (v-PhSe)(v-MeS)[Fe2(CO)6]2(v4-S)
(8)
The flask described above was charged with 0.760 g
(1.5 mmol) of Fe3(CO)12, 15 ml of THF, 0.16 ml (1.1
mmol) of PhSeH and 0.23 ml (1.6 mmol) of Et3N. The
mixture was stirred at r.t. for 0.5 h to give a brown
solution. Upon cooling the solution to –78°C by a dry
ice–acetone bath 0.344 g (1.0 mmol) of m-S2Fe2(CO)6
and 0.13 ml (2.0 mmol) of MeI were added. After the
mixture was warmed naturally to r.t. by removal of the
cooling bath, the mixture was stirred at this tempera-
ture for an additional 12 h. The resulting mixture was
filtered and condensed under reduced pressure. The
residue was subjected to TLC separation using
CH2Cl2–petroleum ether (v/v, 1:20) as eluent. The first
major band gave 0.236 g (53%) of (m-PhSe)2Fe2(CO)6,
which was identified by comparison of its melting point
and 1H-NMR spectrum with those of an authentic
sample [35]. The second major band afforded 0.268 g
(34%) of 8 as a red solid. M.p. 150°C (dec.). Anal.
Found: C, 28.80; H, 1.20. Calc. for C19H8Fe4O12S2Se:
C, 28.70; H, 1.01%. IR (KBr disk): terminal CꢀO,
1
tified by comparison of its melting point and H-NMR
spectrum with those of an authentic sample [3]. The
second major band gave 0.100 g (12%) of 10 as a red
solid. M.p. 130°C (dec.). Anal. Found: C, 28.17; H,
1.05. Calc. for C20H10Fe4O12S2Te: C, 28.02; H, 1.17%.
IR (KBr disk): terminal CꢀO, 2080m, 2048s, 2030vs,
1
1991s cm−1. H-NMR (CDCl3): l 2.16 (s, 3H, SCH3),
2.31 (s, 3H, ArCH3), 7.16 (q, AA%BB%, J=7.5 Hz, 4H,
C6H4) ppm.
3.5. Preparation of
(v-p-MeC6H4Se)(v-PhCH2S)[Fe2(CO)6]2(v4-S) (11)
1
2085m, 2050s, 2035vs, 1991vs, 1969s cm−1. H-NMR
(CDCl3): l 2.17 (s, 3H, CH3), 7.22–7.38 (m, 5H, C6H5)
The procedure for the preparation of 11 is similar to
that of 8, but using 0.256 g (1.5 mmol) of m-p-
MeC6H4SeH and 0.24 ml (1.9 mmol) of PhCH2Br
instead of PhSeH and MeI, respectively. The first major
band separated by TLC using CH2Cl2–petroleum ether
(v/v, 1:10) as eluent afforded 0.234 g (50%) of known
compound (m-p-MeC6H4Se)2Fe2(CO)6 [12]. The second
major band gave 0.392 g (44%) of 11 as a red solid.
ppm. 77Se-NMR (CDCl3, Me2Se): l 249.63 (s) ppm.
3.3. Preparation of
(v-p-MeC6H4Se)(v-MeS)[Fe2(CO)6]2(v4-S) (9)
The procedure for preparation of 9 is similar to that
of 8, but using 0.256 g (1.5 mmol) of m-p-MeC6H4SeH

62
L.-C. Song et al. / Journal of Organometallic Chemistry 623 (2001) 56–64
M.p. 180°C (dec.). Anal. Found: C, 35.25; H, 1.86. Calc.
for C26H14Fe4O12S2Se: C, 35.28; H, 1.58%. IR (KBr
disk): terminal CꢀO, 2081m, 2055s, 2035vs, 2005s,
then was filtered through a ca. 5cm high bed of 200–300
mesh silica gel to remove insoluble materials. The
filtrate was evaporated to dryness at reduced pressure
and the residue was subjected to TLC separation using
petroleum ether as eluent. The first main band gave
0.116 g (20%) of (m-EtTe)2Fe2(CO)6, which was iden-
1
1991s, 1970s cm−1. H-NMR (CDCl3): l 2.28 (s, 3H,
CH3), 3.64 (q, AB pattern, J=12.5 Hz, 2H, CH2), 7.11
(q, AA%BB%, J=8.3 Hz, 4H, C6H4), 7.34 (s, 5H, C6H5)
ppm. 77Se-NMR (CDCl3, Me2Se): l 249.52 (s) ppm.
1
tified by comparison of its IR and H-NMR spectra
with those of an authentic sample [20]. The second main
band afforded 0.113 g (12%) of 14 as a red solid. M.p.
167°C (dec.). Anal. Found: C, 20.74; H, 1.17. Calc. for
C16H10Fe4O12S2Te2: C, 20.50; H, 1.07%. IR (KBr disk):
terminal CꢀO, 2076s, 2049s, 2022vs, 2002s, 1982s,
3.6. Preparation of {(v-t-BuS)Fe2(CO)6]2(v4-S)}2-
[v-p-(SCH2)2C6H4] (12)
The procedure for the preparation of 12 is similar to
that of 7, except that 0.106 g (0.104 mmol) of p-
(BrCH2)2C6H4 was used instead of MeI and the reaction
mixture after adding p-(BrCH2)2C6H4 was stirred for 24
h. CH2Cl2–petroleum ether (v/v, 1:20) was used as
eluent. From the major band 0.330 g (54%) of 12 was
obtained as a red solid. M.p. 172°C (dec.). Anal. Found:
C, 31.21; H, 1.78. Calc. for C40H26Fe8O24S6: C, 31.40;
H, 1.71%. IR (KBr disk): terminal CꢀO, 2083s, 2054vs,
2033vs, 1990vs, 1976vs cm−1. 1H-NMR (CDCl3): l 1.42
(s, 18H, 2 C(CH3)3), 3.60 (q, AB pattern, J=13.0 Hz,
4H, 2CH2), 7.32 (s, 4H, C6H4) ppm.
1
1968vs cm−1. H-NMR (CDCl3): l 1.53 (t, J=6.7 Hz,
6H, 2CH3), 2.76 (q, J=6.7 Hz, 4H, 2CH2) ppm. 125Te-
NMR (CDCl3, Me2Te): l 182.52 (s) ppm.
3.9. Preparation of [(v-i-BuTe)Fe2(CO)6]2(v-S–S-v)
(15)
The same procedure as that for 14 was followed, but
i-BuMgBr was used instead of EtMgBr. From the first
main band was obtained 0.107 g (16%) of (m-i-
BuTe)2Fe2(CO)6, which was identified by comparison of
1
its IR and H-NMR spectra with those of an authentic
3.7. Preparation of {(v-t-BuS)[Fe2(CO)6]2(v4-S)}3-
[(v-1,3,5-(SCH2)3C6H3] (13)
sample [20]. From the second main band was obtained
0.126 g (13%) of 15 as a red solid. M.p. 157°C (dec.).
Anal. Found: C, 24.45; H, 2.00%. Calc. for
C20H18Fe4O12S2Te2: C, 24.18; H, 1.81%. IR (KBr disk):
terminal CꢀO, 2072s, 2046s, 2023vs, 2002s, 1980vs
The procedure for the preparation of 13 is similar to
that of 7, except that 0.107 g (0.30 mmol) of 1,3,5-
(BrCH2)3C6H3 was used instead of MeI and the reaction
mixture after adding 1,3,5-(BrCH2)3C6H3 was stirred for
24 h. CH2Cl2–petroleum ether (v/v, 1:10) was used as
eluent. From the major band 0.253 g (37%) of 13 was
obtained as a red solid. M.p. 113°C (dec.). Anal. Found:
C, 30.18; H, 1.49. Calc. for C57H36Fe12O36S9: C, 30.35;
H, 1.60%. IR (KBr disk): terminal CꢀO, 2082s, 2058vs,
1
cm−1. H-NMR (CDCl3): l 1.06 (d, J=6.5 Hz, 12H,
4CH3), 1.81–2.01 (m, 2H, 2CH), 2.75 (d, J=6.5 Hz, 4H,
2CH2) ppm. 125Te-NMR (CDCl3, Me2Te): l 96.11 (s)
ppm.
3.10. Preparation of [(v-PhTe)Fe2(CO)6]2(v-S–S-v)
(16)
2032vs, 1981vs cm−1 1H-NMR (CDCl3): l 1.43 (s,
.
27H, 3C(CH3)3), 3.48–3.70 (m, 6H, 3CH2), 7.28 (s, 3H,
C6H3) ppm.
The same procedure as that for 14 was followed,
except that PhMgBr was used instead of EtMgBr and the
mixture of PhMgBr and Te powder was refluxed for
0.5 h. The first main band gave 0.293 g (43%) of
(m-PhTe)2Fe2(CO)6, which was identified by comparison
of its IR and 1H-NMR spectra with those of an authen-
tic sample [3]. The second main band gave 0.118 g (11%)
of 16 as a red solid. M.p. 188°C (dec.). Anal. Found: C,
28.07; H, 1.08%. Calc. for C24H10Fe4O12S2Te2: C, 27.89;
H, 0.97%. IR (KBr disk): terminal CꢀO, 2075s, 2052s,
3.8. Preparation of [(v-EtTe)Fe2(CO)6]2(v-S–S-v) (14)
A 100 ml two-necked flask equipped with a magnetic
stir-bar, a serum cap and a reflux condenser topped with
a N2 inlet tube was charged with 0.255 g (2.0 mmol) of
tellurium powder, 20 ml of THF and ca. 2.0 mmol of
EtMgBr in THF. The mixture was stirred at reflux for
8 h to give a light gray solution. After the solution was
cooled to r.t., 1.00 g (2.0 mmol) of Fe3(CO)12 was added
and the reaction mixture was stirred for 0.5 h to produce
a brown solution. The solution was cooled to −78°C
by a dry-ice–acetone bath and then 0.08 ml (1.0 mmol)
of S2Cl2 was added. After the mixture was stirred at
−78°C for 10 min, the cooling bath was removed and
the mixture was naturally warmed to r.t. The mixture
was continuously stirred at this temperature for 2 h and
2025vs, 1990vs, 1968s cm−1 1H-NMR (CDCl3): l
.
7.24–7.43 (m, 10H, 2C6H5) ppm. 125Te-NMR (CDCl3,
Me2Te): l 309.14 (s) ppm.
3.11. Preparation of [(v-p-MeC6H4Te)Fe2(CO)6]2(v-S–
S-v) (17)
The same procedure as that for 14 was followed,
except that p-MeC6H4MgBr was used instead of

L.-C. Song et al. / Journal of Organometallic Chemistry 623 (2001) 56–64
63
Table 3
for 9 and 12 were performed using the TEXSAN crystal-
lographic software package of the Molecular Structure
Corporation.
Crystal data and structural refinements details for 9 and 12
9
12
Formula
C20H10Fe4O12S2Se C40H26Fe8O24S6
Formula weight
Crystal system
Space group
808.76
Ticlinic
P (no. 2)
1529.77
Monoclinic
C2/c (no. 15)
4. Supplementary material
Crystallographic data for the structures reported in
this paper have been deposited with the Cambridge
Crystallographic Data Centre, CCDC no. 144605 for 9
and CCDC no. 144606 for 12. Copies of this informa-
tion may be obtained free of charge from the Director,
CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK
(fax: +44-1223-336-033; e-mail: deposit@ccdc.cam.
ac.uk or http://www.ccdc.cam.ac.uk).
Unit cell dimensions
,
a (A)
8.782(2)
9.093(3)
19.514(7)
86.98(2)
86.42(2)
68.61(2)
1447.5(8)
2
1.855
792
34.03
296
33.755(7)
12.492(2)
15.539(3)
,
b (A)
,
c (A)
h (°)
i (°)
116.49(1)
k (°)
3
,
V (A )
Z
5864(2)
4
1.733
3048
22.06
293
Dcalc (g cm−3
F(000)
)
v(Mo–Ka) (cm−1
)
Acknowledgements
Temperature (K)
,
Wavelength (A)
Scan type
2qmax (°)
0.71069
ꢀ–2q
52.2
3194
352
0.058
0.067
1.60
0.71069
ꢀ–2q
49.9
2966
352
0.036
0.043
1.43
We are grateful to the National Natural Science
Foundation of China, the Laboratory of Organometal-
lic Chemistry and the State Key Laboratory of Struc-
tural Chemistry for financial support of this work.
No. of observations (n)
No. of variables (p)
R
Rw
Goodness-of-fit indicator
Largest peak (e A
−3
,
)
0.81
0.46
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band was obtained 0.316 g (44%) of known compound
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band was obtained 0.148 g (11%) of 17 as a red solid.
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12
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,
with Mo–Ka radiation (u=0.71069 A). Details of the
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.