Synthesis and characterization of double- and triple-butterfly Fe/S cluster complexes obtained from the novel butterfly cluster anions {(μ-RS)(μ-CO)[Fe2(CO)6]2 (μ4-S)}- and (μ-RS)(μ-S-)[Fe2 (CO)6]3(μ4-S)2. Crystal structures of (μ-MeS) (μ-PhNHC double

Article abstract of DOI:10.1021/om0002071

The novel reaction of (μ-RS)(μ-S^-)Fe₂(CO)₆ (1) with Fe₃(CO)₁₂ gives a new type of anion, {(μ-RS)(μ-CO)[Fe₂(CO)₆]₂ (μ₄-S)}^- (4). While anions 4 (R = Me, Et) react with PhNCS/CF₃CO₂H to give the neutral double-cluster complexes (μ-RS)(μ-PhNHC double bond S)[Fe₂(CO)₆]₂(μ₄-S) (6, R = Me; 7, R = Et), the reaction of 4 (R = Me, Ph, p-MeC₆H₄) with CS₂/MeI or PhCH₂Br affords the neutral double-cluster complexes (μ-RS)(μ-MeSC double bond S)[Fe₂(CO)₆]₂(μ₄-S) (8, R = Me; 10, R = p-MeC₆H₄; 12, R = Ph), and (μ-RS)(μ-PhCH₂SC double bond S) [Fe₂(CO)₆]₂(μ₄-S) (9, R = Me; 11, R = p-MeC₆H₄), respectively. More interestingly, reaction of anions 4 with μ-S₂Fe₂(CO)₆ produces another new type of anion, (μ-RS)(μ-S^-)[Fe₂(CO)₆]₃(μ₄-S)₂ (5), which reacts further with MeI, EtBr, or PhCH₂Br to give the neutral triple-cluster complexes (μ-RS)(μ-MeS)[Fe₂(CO)₆]₃ (μ₄-S)₂ (13, R = Me; 14, R = p-MeC₆H₄), (μ-p-MeC₆H₄S)(μ-EtS)[Fe₂(CO)₆]₃ (μ₄-S)₂ (15), and (μ-PhCH₂S)₂[Fe₂ (CO)₆]₃(μ₄-S)₂ (16), respectively. All these new double- and triple-butterfly clusters have been characterized by combustion analyses and spectroscopy as well as by X-ray diffraction for clusters 6, 8, and 16.

Full text of DOI:10.1021/om0002071

Organometallics 2000, 19, 3909-3915
3909
Syn th esis a n d Ch a r a cter iza tion of Dou ble- a n d
Tr ip le-Bu tter fly F e/S Clu ster Com p lexes Obta in ed fr om
th e Novel Bu tter fly Clu ster An ion s
{(µ-RS)(µ-CO)[F e2(CO)6]2(µ4-S)}- a n d
(µ-RS)(µ-S-)[F e2(CO)6]3(µ4-S)2. Cr ysta l Str u ctu r es of
(µ-MeS)(µ-P h NHCdS)[F e2(CO)6]2(µ4-S),
(µ-MeS)(µ-MeSCdS)[F e2(CO)6]2(µ4-S), a n d
(µ-P h CH2S)2[F e2(CO)6]3(µ4-S)2
Li-Cheng Song,*,† Qing-Mei Hu,† Hong-Tao Fan,† Bao-Wei Sun,† Ming-Yi Tang,†
Yu Chen,† Yi Sun,† Cui-Xiang Sun,† and Qiang-J in Wu‡
Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry,
Nankai University, Tianjin 300071, China, and State Key Laboratory of Structural Chemistry,
Fuzhou 350002, China
Received March 3, 2000
The novel reaction of (µ-RS)(µ-S-)Fe2(CO)6 (1) with Fe3(CO)12 gives a new type of anion,
{(µ-RS)(µ-CO)[Fe2(CO)6]2(µ4-S)}- (4). While anions 4 (R ) Me, Et) react with PhNCS/CF3-
CO2H to give the neutral double-cluster complexes (µ-RS)(µ-PhNHCdS)[Fe2(CO)6]2(µ4-S) (6,
R ) Me; 7, R ) Et), the reaction of 4 (R ) Me, Ph, p-MeC6H4) with CS2/MeI or PhCH2Br
affords the neutral double-cluster complexes (µ-RS)(µ-MeSCdS)[Fe2(CO)6]2(µ4-S) (8, R ) Me;
10, R ) p-MeC6H4; 12, R ) Ph), and (µ-RS)(µ-PhCH2SCdS) [Fe2(CO)6]2(µ4-S) (9, R ) Me;
11, R ) p-MeC6H4), respectively. More interestingly, reaction of anions 4 with µ-S2Fe2(CO)6
produces another new type of anion, (µ-RS)(µ-S-)[Fe2(CO)6]3(µ4-S)2 (5), which reacts further
with MeI, EtBr, or PhCH2Br to give the neutral triple-cluster complexes (µ-RS)(µ-MeS)[Fe2-
(CO)6]3(µ4-S)2 (13, R ) Me; 14, R ) p-MeC6H4), (µ-p-MeC6H4S)(µ-EtS)[Fe2(CO)6]3(µ4-S)2 (15),
and (µ-PhCH2S)2[Fe2(CO)6]3(µ4-S)2 (16), respectively. All these new double- and triple-butterfly
clusters have been characterized by combustion analyses and spectroscopy as well as by
X-ray diffraction for clusters 6, 8, and 16.
In tr od u ction
(Chart 1), have been demonstrated to play an important
role in the development of the chemistry of Fe/S cluster
complexes.1-23 More recently, double-butterfly Fe/S
cluster anions containing a µ-S- ligand, (µ-RS)(µ-S-)-
[Fe2(CO)6]2(µ4-S) (3), a higher homologue of 1 (Chart 1),
have been also shown to be important in the develop-
ment of Fe/S cluster chemistry.24-26 Closely related to
these known anions 1-3, one might naturally ask if the
Over the past 15-20 years single-butterfly Fe/S
cluster anions containing a µ-S- ligand, (µ-RS)(µ-S-)-
Fe2(CO)6 (1)1-11 (Chart 1), and the corresponding anions
containing a µ-CO ligand, [(µ-RS)(µ-CO)Fe2(CO)6]- (2)12-23
* To whom correspondence should be addressed. Fax: 0086-22-
23504853. E-mail: lcsong@public.tpt.tj.cn.
† Nankai University.
(13) Seyferth, D.; Hoke, J . B.; Dewan, J . C. Organometallics 1987,
6, 895.
(14) Seyferth, D.; Ruschke, D. P.; Davis, W. M.; Cowie, M.; Hunter,
A. D. Organometallics 1994, 13, 3834.
(15) Delgado, E.; Hernandez, E.; Rossell, O.; Seco, M.; Puebla, E.
G.; Ruiz, C. J . Organomet. Chem. 1993, 455, 177.
(16) Song, L.-C.; Wang, R.-J .; Liu, J .-T.; Wang, H.-G.; Wang, J .-T.
Acta Chim. Sin. 1990, 48, 1141.
‡ State Key Laboratory of Structural Chemistry.
(1) Seyferth, D.; Henderson, R. S. J . Am. Chem. Soc. 1979, 101, 508.
(2) Chieh, C.; Seyferth, D.; Song, L.-C. Organometallics 1982, 1, 473.
(3) Seyferth, D.; Womack, G. B.; Song, L.-C. Organometallics 1983,
2, 776.
(4) Seyferth, D.; Song, L.-C.; Henderson, R. S. J . Am. Chem. Soc.
1981, 103, 5103.
(5) Seyferth, D.; Henderson, R. S.; Song, L.-C.; Womack, G. B. J .
Organomet. Chem. 1985, 292, 9.
(6) Seyferth, D.; Kiwan, A. M. J . Organomet. Chem. 1985, 286, 219.
(7) Song, L.-C.; Kadiata, M.; Wang, J .-T.; Wang, R.-J .; Wang, H.-G.
J . Organomet. Chem. 1988, 340, 239.
(17) Song, L.-C.; Liu, J .-T.; Wang, J .-T. Acta Chim. Sin. 1990, 48,
110.
(18) Song, L.-C.; Hu, Q.-M. J . Organomet. Chem. 1991, 414, 219.
(19) Song, L.-C.; Hu, Q.-M.; Su, Z.-Y.; Cao, X.-C.; Zhu, J . Chem. J .
Chin. Univ. 1995, 16, 905.
(8) Song, L.-C.; Hu, Q.-M.; Shan, Z.-X.; Wang J .-T. Sci. Sin., Ser. B
(Engl. Ed.) 1988, 31, 393.
(9) Song, L.-C.; Kadiata, M.; Wang, J .-T.; Wang, R.-J .; Wang, H.-G.
J . Organomet. Chem. 1990, 391, 387.
(20) Song, L.-C.; Yan, C.-G.; Hu, Q.-M.; Wang, R.-J .; Mak, T. C. W.
Organometallics 1995, 14, 5513.
(21) Song, L.-C.; Yan, C.-G.; Hu, Q.-M.; Wu, B.-M.; Mak, T. C. W.
Organometallics 1997, 16, 632.
(10) Song, L.-C.; Hu, Q.-M.; J ia, G.-F.; Wang J .-Y. Sci. China, Ser.
B 1992, 35, 1.
(11) Song, L.-C.; Qin, X.-D.; Hu, Q.-M.; Huang, X.-Y. Organometallics
1998, 17, 5437.
(22) Song, L.-C.; Yan, C.-G.; Hu, Q.-M.; Wang, R.-J .; Mak, T. C. W.;
Huang, X.-Y. Organometallics 1996, 15, 1535.
(23) Song, L.-C.; Fan, H.-T.; Hu, Q.-M.; Qin, X.-D.; Zhu, W.-F.; Chen.
Y.; Sun, J . Organometallics 1998, 17, 3454.
(12) Seyferth, D.; Womack, G. B.; Dewan, J . C. Organometallics
1985, 4, 398.
(24) Song, L.-C.; Lu, G.-L.; Hu, Q.-M.; Fan, H.-T.; Chen, Y.; Sun, J .
Organometallics 1999, 18, 3258.
10.1021/om0002071 CCC: $19.00 © 2000 American Chemical Society
Publication on Web 08/22/2000

3910 Organometallics, Vol. 19, No. 19, 2000
Song et al.
Sch em e 1
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 6
Ch a r t 1
Fe(1)-S(1)
Fe(2)-S(1)
Fe(3)-S(1)
Fe(3)-Fe(4)
N(1)-C(1)
2.251(1)
2.241(1)
2.225(1)
2.627(1)
1.316(6)
Fe(1)-S(2)
Fe(2)-S(2)
Fe(3)-S(3)
Fe(4)-S(1)
S(2)-C(2)
2.254(1)
2.267(1)
2.312(1)
2.250(2)
1.801(5)
S(1)-Fe(1)-S(2)
77.65(5) S(1)-Fe(1)-Fe(2)
55.37(4)
71.91(4)
68.87(4)
125.3(4)
77.59(5)
55.56(4)
77.28(4)
Fe(3)-S(1)-Fe(2) 134.85(6) Fe(3)-S(1)-Fe(4)
Fe(2)-S(1)-Fe(4) 127.56(6) Fe(2)-S(1)-Fe(1)
Fe(1)-S(2)-Fe(2)
S(3)-C(1)-Fe(4)
S(1)-Fe(2)-Fe(1)
S(1)-Fe(3)-S(3)
68.37(4) N(1)-C(1)-Fe(4)
114.6(2)
S(1)-Fe(2)-S(2)
55.76(4) S(2)-Fe(2)-Fe(1)
86.20(5) S(3)-Fe(3)-Fe(4)
higher homologue of 2, namely, the double-butterfly
Fe/S cluster anions {(µ-RS)(µ-CO)[Fe2(CO)6]2(µ4-S)}- (4),
and that of 3, i.e., the triple-butterfly Fe/S cluster anions
{(µ-RS)(µ-S-)[Fe2(CO)6]3(µ4-S)2}- (5) (Chart 1), could
also be prepared and if these compounds would be rich
in chemical reactivities. It is evident that such questions
are both challenging and interesting for further devel-
opment of the Fe/S cluster chemistry. This article will
answer these questions by describing the formation of
the novel double- and triple-butterfly cluster anions 4
and 5, as well as their nucleophilicity toward various
electrophiles leading to a series of neutral double- and
triple-butterfly Fe/S cluster complexes.
Products 6 and 7 derived from anions 4 have been
characterized by elemental and spectroscopic analyses,
and in particular by an X-ray crystallographic study of
6. The IR spectra of 6 and 7 showed several absorption
bands in the range 2079-1953 cm-1 for their terminal
carbonyls28 and one absorption band at about 950 cm-1
1
for their coordinated CdS bonds.29 In addition, the H
NMR spectra of 6 and 7 displayed a singlet at about
8.65 ppm for their NH groups and corresponding signals
for their methyl, ethyl, and phenyl groups. To confirm
the structures of 6 and 7, a single-crystal diffraction
analysis of 6 was undertaken. Selected bond lengths and
angles of 6 are given in Table 1. Figure 1 illustrates its
molecular structure, which shows that it has the double-
butterfly cluster skeleton Fe(1)Fe(2)S(1)S(2) and Fe(3)-
Fe(4)S(1)C(1)S(3) joined to a spiro type of µ4-S[S(1)]
atom. On this double-cluster skeleton, each Fe atom is
attached to three terminal carbonyls, whereas the S(2)
and C(1) atoms are bonded to an Me group and the N(1)
atom of the PhNH group, respectively. While the
geometric parameters of the subcluster core Fe(1)-
Fe(2)S(1)S(2) are very similar to those of the butterfly
Fe2S2 cluster cores present in crystallographically char-
acterized double clusters, such as [(µ-MeS)Fe2(CO)6]2-
(µ4-S)30 and [(µ-EtS)Fe2(CO)6]2(µ4-S),7 the geometric
parameters of another subcluster core, Fe(3)Fe(4)S(1)C-
(1)S(3), are similar to those of butterfly Fe2CSSe (or S)
cluster cores present in the single clusters, such as (µ-
PhSe)(µ-PhCH2SCdS)Fe2(CO)6.20 For example, the bond
Resu lts a n d Discu ssion
Rea ction of th e An ion s {(µ-RS)(µ-CO)[F e2(CO)6]2-
(µ4-S)}- (4) Lea d in g to (µ-RS)(µ-P h NHCdS)[F e2-
(CO)6]2(µ4-S) (6, R ) Me; 7, R ) Et). Cr ysta l Str u c-
tu r e of 6. It was found that the [MgX]+ (X ) I, Br) salts
of the anions (µ-RS)(µ-S-)Fe2(CO)6 (1; R ) Me, Et)
prepared from the complex µ-S2Fe2(CO)6 and the Grig-
nard reagent MeMgI or EtMgBr5 reacted in situ with
Fe3(CO)12 in THF to give the double-butterfly Fe/S
cluster anions 4 (R ) Me, Et) as their [MgX]+ (X ) I,
Br) salts, which reacted in situ further, in a manner
similar to their homologue 2,27 with the electrophile
PhNCS followed by treatment of the intermediate m 1
with CF3CO2H to give the double-butterfly Fe/S clusters
6 and 7, each containing a thiocarbamato ligand, as
shown in Scheme 1.
(28) Collman, J . P.; Hegedus, L. S.; Norton, J . R.; Finke, R. G.
Principles and Applications of Organotransition Metal Chemistry, 2nd
ed.; University Science Books: Mill Valley, CA, 1987.
(29) Patin, H.; Mignani, G.; Mahe, C.; Le Marouille, J .-Y.; Southern,
T. G.; Benoit, A.; Grandjean, D. J . Organomet. Chem. 1980, 197, 315.
(30) Coleman, J . M.; Wojcicki, A.; Pollick, P. J .; Dahl, L.-F. Inorg.
Chem. 1967, 6, 1236.
(25) Song, L.-C.; Lu, G.-L.; Hu, Q.-M.; Sun, J . Organometallics 1999,
18, 5429.
(26) Wang, Z.-X.; J ia, C.-S.; Zhou, Z.-Y.; Zhou, X.-G. J . Organomet.
Chem. 1999, 580, 201.
(27) Seyferth, D.; Womack, G. B.; Archer, C. M.; Fackler, J . P., J r.;
Marler, D. O. Organometallics 1989, 8, 443.

Double- and Triple-Butterfly Fe/ S Cluster Complexes
Organometallics, Vol. 19, No. 19, 2000 3911
Sch em e 2
Ch a r t 2
subsequent in situ reaction with CS2, in a fashion
similar to their analogue 2,27 followed by treatment of
the intermediate m 2 with MeI or PhCH2Br afforded the
double-butterfly clusters 8-12, each containing a dithio-
formato ligand, as shown in Scheme 2.
Clusters 8-12 have been fully characterized by
1
combustion analysis and IR and H NMR spectroscopy,
as well as by X-ray diffraction techniques for 8. The IR
spectra of 8-12, similar to those of 6 and 7, displayed
several absorption bands in the range 2084-1983 cm-1
for their terminal carbonyls28 and one absorption band
at ca. 1010 cm-1 for their coordinated CdS bonds.29 It
1
F igu r e 1. ORTEP drawing of 6 with atom-labeling
scheme.
is worth pointing out that the H NMR spectra demon-
strated that while 8, 10, and 12 contain two isomers, 9
and 11 contain only one. This is because the methyl
groups attached to S atoms of the dithioformato ligands
in the former showed two singlets in the range 2.57-
2.69 ppm, whereas the methylenes of benzyl groups in
the dithioformato ligands in the latter displayed only
one quartet (due to coupling between the two magneti-
cally nonequivalent protons of the CH2 group) at 4.35
and 4.41 ppm, respectively. As we know, the R group
in µ4-S-containing clusters 8-12 should be attached to
the bridged S atom only by an equatorial bond to avoid
the strong axial-axial steric repulsions.22,31 In addition,
the Me and PhCH2 groups attached to the S atom of
dithioformato ligands in 8-12 could be located either
inside or outside the butterfly subcluster core Fe2SCd
S, or more exactly, the inside or outside of the dihedral
angle of the two wings of the butterfly cluster core Fe2-
SCdS. Therefore, the two isomers for 8, 10, and 12
would be e(R) endo(Me) and e(R) exo(Me), as shown in
Chart 2. The one isomer for 9 and 11 might be e(R)
exo(PhCH2), and the other isomer e(R) endo(PhCH2) for
9 and 11 was not obtained, possibly due to the strong
steric repulsions between the larger PhCH2 group and
the bulky subcluster moiety (µ-RS)Fe2(CO)6(µ4-S).
length of Fe(3)-Fe(4) in the subcluster core Fe(3)-
Fe(4)S(1)C(1)S(3) of 6 (2.627(1) Å) is slightly shorter
than that of Fe-Fe (2.648(3) Å) in the subcluster core
Fe2CSSe of (µ-PhSe)(µ-PhCH2SCdS)Fe2(CO)6,20 and the
bond length of the thiocarbonyl C(1)-S(3) in 6 (1.698-
(5) Å) is slightly longer than the corresponding thiocar-
bonyl CdS in (µ-PhSe)(µ-PhCH2SCdS)Fe2(CO)6 (1.63(1)
Å).20 In addition, it can be seen from Figure 1 that C(2)
is bonded to S(2) by an equatorial (abbreviated as e
hereafter) bond; that is, the methyl group is at an
equatorial position and thus 6 belongs to an e-type of
isomer.31
Rea ction of th e An ion s {(µ-RS)(µ-CO)[F e2(CO)6]2-
(µ4-S)}- (4) Leadin g to (µ-RS)(µ-MeSCdS)[Fe2(CO)6]2-
(µ4-S) (8, R ) Me; 10, R ) p-MeC6H4; 12, R ) P h )
a n d (µ-RS)(µ-P h CH2SCdS)[F e2(CO)6]2(µ4-S) (9, R )
Me; 11, R ) p-MeC6H4). Cr ysta l Str u ctu r e of 8. We
further found that the [MgX]+ (X ) I, Br) salts of the
anions (µ-RS)(µ-S-)Fe2(CO)6 (1; R ) Me, p-MeC6H4, Ph)
prepared from µ-S2Fe2(CO)6 and the Grignard reagent
MeMgI, p-MeC6H4MgBr, or PhMgBr5 reacted in situ
with Fe3(CO)12 in THF to give the [MgX]+ (X ) I, Br)
salts of the anions 4 (R ) Me, p-MeC6H4, Ph), whose
Fortunately, for 8 one of its two isomers, i.e., isomer
e(Me) exo(Me), has been separated by recrystallization
of its isomer mixture (not being separated by TLC) in
(31) Shaver, A.; Fitzpatrick, P. J .; Steliou, K.; Butler, I. S. J . Am.
Chem. Soc. 1979, 101, 1313.

3912 Organometallics, Vol. 19, No. 19, 2000
Song et al.
Sch em e 3
F igu r e 2. ORTEP drawing of 8 with atom-labeling
scheme.
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 8
Fe(1)-S(3)
Fe(3)-S(3)
Fe(3)-Fe(4)
Fe(2)-S(2)
Fe(4)-S(4)
2.2455(10)
2.2584(10)
2.5376(8)
2.3100(11)
2.2660(11)
Fe(1)-Fe(2)
Fe(3)-S(4)
Fe(2)-S(3)
Fe(4)-S(3)
S(1)-C(14)
2.6496(7)
2.2768(11)
2.2433(10)
2.2615(9)
1.803(4)
thiocarbonyl in 8 (C(13)-S(2)) is slightly shorter than
that of 6 (C(1)-S(3)) but slightly longer than that of (µ-
PhSe)(µ-PhCH2SCdS)Fe2(CO)6 (1.63(1) Å),20 which are
all much longer than that of a typical CdS double bond
in free CS2 (1.554 Å).32
S(3)-Fe(3)-S(4)
S(4)-Fe(3)-Fe(4)
S(3)-Fe(2)-Fe(1)
S(3)-Fe(4)-S(4)
S(4)-Fe(4)-Fe(3)
Fe(3)-S(3)-Fe(4)
76.76(4)
55.84(3)
53.86(3)
76.91(4)
56.24(3)
68.31(3)
S(3)-Fe(3)-Fe(4)
S(3)-Fe(2)-S(2)
S(2)-Fe(2)-Fe(1)
S(3)-Fe(4)-Fe(3)
Fe(2)-S(3)-Fe(1)
Fe(4)-S(4)-Fe(3)
55.90(3)
85.91(4)
75.65(3)
55.79(3)
72.35(3)
67.92(3)
Rea ction of th e An ion s (µ-RS)(µ-S-)[F e2(CO)6]3-
(µ4-S)2 (5) Lea d in g to (µ-RS)(µ-MeS)[F e2(CO)6]3(µ4-
S)2 (13, R ) Me; 14, R ) p-MeC6H4), (µ-p-MeC6H4S)-
(µ-E t S)[F e2(CO)6]3(µ4-S)2 (15), a n d (µ-P h CH 2S)2-
[F e2(CO)6]3(µ4-S)2 (16). Cr ysta l Str u ctu r e of 16.
More interestingly, it was also found that the [MgX]+
(X ) I, Br) salts of anions 4 (R ) Me, p-MeC6H4, PhCH2)
could react with µ-S2Fe2(CO)6 to give the triple-butterfly
Fe/S cluster anions 5 (R ) Me, p-MeC6H4, PhCH2),
higher homologues of anions 3, as their [MgX]+ (X ) I,
Br) salts. Treatment of this type of anion in situ with
MeI, EtBr, or PhCH2Br afforded not only symmetrical
neutral triple-butterfly Fe/S cluster complexes 13 and
16 but also the unsymmetrical complexes 14 and 15,
as shown in Scheme 3.
CH2Cl2/petroleum ether. This isomer was characterized
1
by H NMR spectroscopy (one singlet at 2.25 ppm for
µ-MeS and another singlet at 2.65 ppm for µ-MeSCdS)
and was confirmed by X-ray diffraction analysis. The
molecular structure of 8 is shown in Figure 2, and its
selected bond lengths and angles are presented in Table
2. Figure 2 shows that 8 is very similar to 6, which
consists of the two butterfly subcluster cores Fe(1)Fe-
(2)S(3)C(13)S(2) and Fe(3)Fe(4)S(3)S(4) joined together
to a spiro type of µ4-S atom, i.e., S(3). Indeed, as seen
intuitively from Figure 2, the S(4) atom is bonded to
C(15) of the Me group by an equatorial type of bond31
and C(14) of another Me group is located outside the
subcluster core Fe(1)Fe(2)S(3)C(13)S(2); that is, 8 is an
e(Me) exo(Me) isomer. Interestingly, it can be seen from
Figure 1 that 6 is also an e/ exo type of isomer: i.e., the
e(Me) exo(PhNH) isomer. Similarly to 9 and 11, cluster
6 exists only as one such isomer in order to avoid the
strong steric repulsions between the larger PhNH group
and the subcluster moiety (µ-MeS)Fe2(CO)6(µ4-S) in the
isomer e(Me) endo(PhNH). The corresponding geometric
parameters of 6 and 8 are very similar. For example,
in 6 the bond lengths are Fe(1)-Fe(2) ) 2.540(1) Å,
Fe(3)-Fe(4) ) 2.627(1) Å, and C(1)-S(3) ) 1.698(5) Å,
whereas in 8 they are Fe(3)-Fe(4) ) 2.5376(8) Å,
Fe(1)-Fe(2) ) 2.6496(7) Å, and C(13)-S(2) ) 1.672(4)
Å. In addition, in 6 the dihedral angles between Fe(1)-
Fe(2)S(1) and Fe(1)Fe(2)S(2) and between Fe(3)Fe(4)-
S(1) and Fe(3)Fe(4)C(1)S(3) are 81.28 and 84.28°, whereas
in 8 the angles between Fe(3)Fe(4)S(3) and Fe(3)Fe(4)-
S(4) and between Fe(1)Fe(2)S(3) and Fe(1)Fe(2)C(13)-
S(2) are 82.82 and 84.45°. It follows that the coordinated
Products 13-16 generated from anions 5 have been
fully characterized by elemental analysis and IR and
1H NMR spectroscopy, as well as by X-ray diffraction
of 16. The IR spectra of 13-16 exhibited two or four
absorption bands in the range 2056-1986 cm-1 for their
1
terminal carbonyls.28 In addition, the H NMR spectra
of 13-16 displayed only one signal or one set of signals
for their Me, Et, PhCH2, and p-MeC6H4 groups. For
1
example, in the H NMR spectrum of 13 there is only
one singlet at 2.20 ppm for the magnetically equivalent
three protons in each of its two identical Me groups,
whereas in that of 16 there is only one quartet at 3.66
ppm for the magnetically nonequivalent two protons in
each of its two methylenes in benzyl groups. This
observation is completely consistent with the fact that
the µ4-S-containing butterfly Fe/S clusters have only one
isomer in which the substituents are attached to bridged
S atoms by an equatorial type of bond.22,31
Figure 3 shows the ORTEP drawing of the structure
of 16. Table 3 lists its selected bond lengths and angles.
(32) Butler, I. S.; Fenster, A. E. J . Organomet. Chem. 1974, 66, 161.

Double- and Triple-Butterfly Fe/ S Cluster Complexes
Organometallics, Vol. 19, No. 19, 2000 3913
respectively. Anions 4 and 5 have proved to be very
useful in the synthesis of neutral double- and triple-
butterfly Fe/S cluster complexes 6-16, which were fully
characterized by spectroscopy and X-ray diffraction.
Considering that the double- and triple-butterfly anions
4 and 5 are produced by reaction of the single-butterfly
anions (µ-RS)(µ-S-)Fe2(CO)6 (1) with Fe3(CO)12 and the
double-butterfly anions 4 with µ-S2Fe2(CO)6, respec-
tively, we might imagine that the higher homologues
of 4 and 5 could be also produced by reaction of 3 with
Fe3(CO)12 and by further reaction with µ-S2Fe2(CO)6. In
addition, considering that 6-16 can be yielded from 4
and 5, the higher homologues of 6-16 could be similarly
produced by subsequent reactions of the higher homo-
logues of 4 and 5 with corresponding electrophiles.
Therefore, these two novel types of anions 4 and 5, as
well as the two new reactions of anions 1 with Fe3(CO)12
and anions 4 with µ-S2Fe2(CO)6, are very important for
further development of Fe/S cluster chemistry.
F igu r e 3. ORTEP drawing of 16 with atom-labeling
scheme.
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 16
Exp er im en ta l Section
Fe(1)-Fe(2)
Fe(1)-S(1)
Fe(2)-S(1)
Fe(3)-S(2)
Fe(4)-S(2)
Fe(5)-S(2)
Fe(6)-S(1)
2.516(2)
2.276(2)
2.270(2)
2.275(2)
2.270(2)
2.264(2)
2.258(2)
Fe(1)-S(3)
Fe(2)-S(3)
Fe(3)-S(4)
Fe(4)-S(4)
Fe(5)-S(1)
Fe(5)-Fe(6)
Fe(6)-S(2)
2.264(2)
2.266(2)
2.272(3)
2.263(2)
2.253(2)
2.575(2)
2.260(2)
Gen er a l Com m en ts. All reactions were carried out under
an atmosphere of prepurified nitrogen using standard Schlenk
and vacuum-line techniques. Tetrahydrofuran (THF) was
distilled from Na/benzophenone ketyl under nitrogen. Fe3-
(CO)12,34 µ-S2Fe2(CO)6,35 and Grignard reagents RMgX36 were
prepared according to literature procedures. PhNCS, CF3-
CO2H, CS2, MeI, EtBr, PhBr, PhCH2Br, and p-MeC6H4Br were
of commercial origin and used without further purification.
Preparative TLC was carried out on glass plates (26 × 20 ×
0.25 cm) coated with silica gel H (10-40 µm). IR spectra were
recorded on a Nicolet FT-IR infrared spectrophotometer. 1H
NMR spectra were recorded on a Bruker AC-P200 NMR
spectrometer. C/H analyses were performed on a Yanaco CHN
Corder MT-3 analyzer. Melting points were determined on a
Yanaco MP-500 apparatus and were uncorrected.
S(3)-Fe(1)-Fe(2)
S(1)-Fe(1)-Fe(2)
S(4)-Fe(4)-S(2)
S(1)-Fe(5)-S(2)
S(2)-Fe(5)-Fe(6)
Fe(1)-S(3)-Fe(2)
Fe(4)-S(4)-Fe(3)
56.29(6)
56.29(6)
76.91(8)
82.58(7)
55.24(6)
67.48(7)
67.14(7)
S(4)-Fe(3)-S(2)
S(2)-Fe(3)-Fe(4)
S(1)-Fe(6)-S(2)
S(2)-Fe(6)-Fe(5)
Fe(5)-S(1)-Fe(6)
Fe(2)-S(1)-Fe(1)
Fe(6)-S(2)-Fe(5)
76.64(8)
56.41(6)
82.56(7)
55.39(6)
69.60(7)
67.22(6)
69.36(6)
It can be seen in Figure 3 that 16 comprises, indeed,
the three butterfly Fe2S2 subcluster cores Fe(1)Fe(2)-
S(1)S(3), Fe(5)Fe(6)S(1)S(2), and Fe(3)Fe(4)S(2)S(4) joined
together by two µ4-S (S(1) and S(2)) atoms. In addition,
each Fe atom has three terminal CO ligands, and each
benzyl group is bonded to S(3) and S(4) atoms by an
equatorial bond, respectively. This molecule is chiral
and has a C2 axis passing through the two midpoints of
Fe(5)-Fe(6) and S(1)‚‚‚S(2). It is noteworthy that the
geometric parameters of the middle subcluster core are
somewhat different from those of the two side subcluster
cores. For example, the bond length of Fe(1)-Fe(2)
(2.516(2) Å) or Fe(3)-Fe(4) (2.508(2) Å) is shorter than
that of Fe(5)-Fe(6) (2.575(2) Å). The dihedral angles
between Fe(1)-Fe(2)-S(1) and Fe(1)-Fe(2)-S(3) (95.64°)
and between Fe(3)-Fe(4)-S(2) and Fe(3)-Fe(4)-S(4)
(88.22°) are larger than that between Fe(5)-Fe(6)-S(1)
and Fe(5)-Fe(6)-S(2) (73.23°). In fact, the basic geo-
metric parameters of 16 are comparable with those of
butterfly Fe/S cluster complexes, such as (µ-EtS)(µ-PhS)-
[Fe2(CO)6]2(µ4-S)33 and (µ-t-BuS)2[Fe2(CO)6]3(µ4-S)2.24
P r ep a r a tion of (µ-MeS)(µ-P h NHCdS)[F e2(CO)6]2(µ4-S)
(6). A 100 mL two-necked flask equipped with a stir bar, an
N2 inlet tube, and a serum cap was charged with 0.172 g (0.5
mmol) of µ-S2Fe2(CO)6 and 10 mL of THF. The resulting red
solution was stirred and cooled to -78 °C using a dry
ice/acetone bath. Into this solution was injected a solution of
MeMgI/Et2O by a syringe until the mixture turned to emerald
green. The mixture was stirred for an additional 20 min, and
0.252 g (0.5 mmol) of Fe3(CO)12 was added. After the bath was
removed, the mixture was naturally warmed to room temper-
ature and then was stirred at this temperature for 2 h to give
a red-brown solution of the [MgI]+ salt of the anion {(µ-MeS)-
(µ-CO)[Fe2(CO)6]2(µ4-S)}-. To this solution was added 0.12 mL
(1.0 mmol) of PhNCS, and the mixture was stirred for 2 h.
Then, 0.08 mL (1.0 mmol) of CF3CO2H was added and the
mixture was stirred for an additional 2 h. Solvent was removed
under reduced pressure. The residue was subjected to TLC
separation using CH2Cl2/petroleum ether (v/v, 1/4) as eluent.
From the main orange-red band 0.100 g (26%) of 6 was
obtained as an orange-red solid. Mp: 146 °C dec. Anal. Calcd
for C20H9Fe4NO12S3: C, 31.00; H, 1.17; N, 1.81. Found: C,
30.96; H, 1.20; N, 1.86. IR (KBr disk): νCtO 2079 (s), 2054 (vs),
2030 (vs), 1986 (vs), 1953 (s); νCdS 944 (w) cm-1 1H NMR
.
(CDCl3): 2.25 (s, 3H, CH3), 7.37 (s, 5H, C6H5), 8.70 (s, 1H, NH)
Con clu sion s
ppm.
We have successfully synthesized two novel types of
butterfly Fe/S cluster anions, {(µ-RS)(µ-CO)[Fe2(CO)6]2-
(µ4-S)}- (4) and (µ-RS)(µ-S-)[Fe2(CO)6]3(µ4-S)2 (5), through
two new reactions of the anions (µ-RS)(µ-S-)Fe2(CO)6
(1) with Fe3(CO)12 and anions 4 with µ-S2Fe2(CO)6,
P r ep a r a tion of (µ-EtS)(µ-P h NHCdS)[F e2(CO)6]2(µ4-S)
(7). The same procedure as that for 6 was followed, but
(34) King, R. B. Organometallic Syntheses; Transition-Metal Com-
pounds; Academic Press: New York, 1965; Vol. 1, p 95.
(35) Seyferth, D.; Henderson, R. S.; Song, L.-C. Organometallics
1982, 1, 125.
(33) Song, L.-C.; Hu, Q.-M.; Zhang, L.-Y.; Wang, H.; Zhou, Z.-Y.; Liu,
L. J . Organomet. Chem. 1991, 412, C19.
(36) Gilman, H.; Zoellner, E. A.; Dickey, J . B. J . Am. Chem. Soc.
1929, 51, 1576.

3914 Organometallics, Vol. 19, No. 19, 2000
Song et al.
Ta ble 4. Cr ysta l Da ta a n d Str u ctu r a l Refin em en t
Deta ils for 6, 8, a n d 16
EtMgBr/Et2O was used instead of MeMgI/Et2O to prepare the
[MgBr]+ salt of the anion {(µ-EtS)(µ-CO)[Fe2(CO)6]2(µ4-S)}-.
From the main orange-red band 0.083 g (21%) of 7 was
obtained as a orange-red solid. Mp: 140 °C dec. Anal. Calcd
for C21H11Fe4NO12S3: C, 31.97; H, 1.41; N, 1.78. Found: C,
32.09; H, 1.41; N, 1.79. IR (KBr disk): νCtO 2081 (s), 2052 (vs),
6
8
16
formula
fw
C
20H9Fe4N-
C15H6Fe4-
C32H14Fe6-
O
12S3
O
12S4
O
18S4
774.86
729.84
1149.77
1
2029 (vs), 2008 (s), 1993 (vs) 1975 (s); νCdS 948 (w) cm-1. H
cryst dimens, mm 0.60 × 0.50 × 0.20 × 0.25 × 1.00 × 0.30 ×
NMR (CDCl3): 1.43 (t, J ) 7.2 Hz, 3H, CH3). 2.55 (q, J ) 7.2
Hz, 2H, CH2), 7.24-7.37 (m, 5H, C6H5), 8.63 (s, 1H, NH) ppm.
P r ep a r a t ion of (µ-MeS)(µ-MeSCdS)[F e2(CO)6]2(µ4-S)
(8). To the [MgI]+ salt of the anion {(µ-MeS)(µ-CO)[Fe2(CO)6]2-
(µ4-S)}-, prepared as described above, was added 0.10 mL (1.8
mmol) of CS2. The mixture was stirred at room temperature
for 1 h, and then 0.10 mL (1.6 mmol) of MeI was added. The
mixture was stirred for an additional 12 h. Solvent was
removed under reduced pressure. The residue was subjected
to TLC separation using petroleum ether as eluent. From the
main orange-red band 0.170 g (47%) of 8 was obtained as an
orange-red solid. Mp: 37-38 °C. Anal. Calcd for C15H6-
Fe4O12S4: C, 24.68; H, 0.83. Found: C, 24.54; H, 0.91. IR (KBr
disk): νCtO 2084 (s), 2055 (vs), 2033 (vs), 1991 (vs); νCdS 1019
0.30
0.30
0.10
cryst syst
space group
a, Å
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å3
monoclinic
P21/c (No. 14) P1h (No. 2)
10.816(4)
15.820(3)
16.541(3)
triclinic
monoclinic
P21/n (No. 14)
10.281(4)
29.454(7)
13.971(4)
9.3683(9)
9.5511(9)
15.6898(15)
75.976(2)
80.678(2)
71.735(2)
1287.8(2)
2
95.94(2)
92.24(2)
2815(1)
4
1.83
4227(2)
4
1.81
Z
D
calcd, g cm-3
1.882
F(000)
1536
22.93
296
720
25.87
298
2280
22.66
296
µ(Mo KR), cm-1
temp, K
wavelength, Å
scan type
2θmax, deg
no. of observns, n 4025
no. of variables, p 361
0.710 69
ω-2θ
52.0
0.710 73
ω-2θ
0.710 69
ω-2θ
52.0
5041
541
1
(m) cm-1. H NMR (CDCl3): 2.21, 2.24 (s, s, 3H, SCH3), 2.57,
2.65 (s, s, 3H, SdCSCH3) ppm.
50.06
P r ep a r a tion of (µ-MeS)(µ-P h CH2SCdS)[F e2(CO)6]2(µ4-
S) (9). To the [MgI]+ salt of the anion {(µ-MeS)(µ-CO)[Fe2-
(CO)6]2(µ4-S)}-, prepared as described above, was added 0.10
mL (1.8 mmol) of CS2. The mixture was stirred at room
temperature for 1 h, and then 0.18 mL (1.5 mmol) of PhCH2-
Br was added. The mixture was stirred for an additional 12
h. The solvent was removed under reduced pressure. The
residue was subjected to TLC separation using petroleum ether
as eluent. From the main orange-red band 0.180 g (45%) of 9
was obtained as an orange-red solid. Mp: 128 °C dec. Anal.
Calcd for C21H10Fe4O12S4: C, 31.29; H, 1.25. Found: C, 31.24;
H, 1.36. IR (KBr disk): νCtO 2081 (s), 2054 (vs), 2036 (vs), 2013
4535
316
R
Rw
0.039
0.060
1.76
0.0342
0.0788
0.985
0.050
0.075
1.81
goodness of fit
largest diff peak, 0.94
0.324
0.76
e Å-3
The mixture was stirred at room temperature for 1 h, and then
0.10 mL (1.6 mmol) of MeI was added. The mixture was stirred
for an additional 12 h. Solvent was removed under reduced
pressure. The residue was subjected to TLC separation using
petroleum ether as eluent. From the main orange-red band
0.188 g (48%) of 12 was obtained as an orange-red solid. Mp:
164 °C dec. Anal. Calcd for C20H8Fe4O12S4: C, 30.33; H, 1.02.
Found: C, 30.04; H, 0.88. IR (KBr disk): νCtO 2084 (m), 2058
(vs), 2036 (vs), 1998 (vs), 1997 (s); νCdS 1020 (m) cm-1. 1H NMR
(CDCl3): 2.62, 2.69 (s, s, 3H, CH3), 7.24-7.37 (m, 5H, C6H5)
ppm.
1
(s), 1983 (vs); νCdS 1009 (m) cm-1. H NMR (CDCl3): 2.25 (s,
3H, CH3), 4.35 (q, AB pattern, 2H, CH2), 7.24-7.30 (m, 5H,
C6H5) ppm.
P r ep a r a tion of (µ-p-MeC6H4S)(µ-MeSCdS)[F e2(CO)6]2-
(µ4-S) (10). To the [MgBr]+ salt of the anion {(µ-p-MeC6H4S)-
(µ-CO)[Fe2(CO)6]2(µ4-S)}-, prepared similarly from (p-MeC6H4)-
MgBr/Et2O, µ-S2Fe2(CO)6, and Fe3(CO)12, was added 0.10 mL
(1.8 mmol) of CS2. The mixture was stirred at room temper-
ature for 1 h, and then 0.10 mL (1.6 mmol) of MeI was added.
The mixture was stirred for an additional 12 h. Solvent was
removed under reduced pressure. The residue was subjected
to TLC separation using petroleum ether as eluent. From the
main orange-red band 0.208 g (52%) of 10 was obtained as an
P r ep a r a t ion of (µ-MeS)2[F e2(CO)6]3(µ4-S)2 (13). The
[MgI]+ salt of the anion {(µ-MeS)(µ-CO)[Fe2(CO)6]2(µ4-S)}- as
described above was cooled to -78 °C using a dry ice/acetone
bath, and then 0.172 g (0.5 mmol) of µ-S2Fe2(CO)6 was added.
The mixture was stirred for 2 h at this temperature to give
the [MgI]+ salt of the anion (µ-MeS)(µ-S-)[Fe2(CO)6]3(µ4-S)2 and
then was warmed to room temperature. To this mixture was
added 0.10 mL (1.6 mmol) of MeI, and the new mixture was
stirred for 14 h. Solvent was removed under reduced pressure.
The residue was subjected to TLC separation using petroleum
ether as eluent. From the main red band 0.150 g (30%) of 13
was obtained as a red solid. Mp: 153 °C dec. Anal. Calcd for
C20H6Fe6O18S4: C, 24.08; H, 0.61. Found: C, 23.87; H, 0.86.
IR (KBr disk): νCtO 2056 (vs), 2037 (vs), 2018 (s), 1986 (vs)
orange-red solid. Mp: 153 °C dec. Anal. Calcd for C21H10
-
Fe4O12S4: C, 31.29; H, 1.25. Found: C, 31.09; H, 1.11. IR (KBr
disk): νCtO 2084 (s), 2057 (vs), 2034 (vs), 1992 (vs); νCdS 1017
(m) cm-1. 1H NMR (CDCl3): 2.29 (s, 3H, CH3), 2.62, 2.69 (s, s,
3H, SdCSCH3), 7.01-7.24 (m, 4H, C6H4) ppm.
P r ep a r a tion of (µ-p-MeC6H4S)(µ-P h CH2SCdS)[F e2-
(CO)6]2(µ4-S) (11). To the [MgBr]+ salt of the anion {(µ-p-
MeC6H4S)(µ-CO)[Fe2(CO)6]2(µ4-S)}- was added 0.10 mL (1.8
mmol) of CS2. The mixture was stirred at room temperature
for 1 h, and then 0.18 mL (1.5 mmol) of PhCH2Br was added.
The mixture was stirred for an additional 12 h. Solvent was
removed under reduced pressure. The residue was subjected
to TLC separation using petroleum ether as eluent. From the
main orange-red band 0.221 g (50%) of 11 was obtained as an
1
cm-1. H NMR (CDCl3): 2.20 (s, 6H, 2CH3) ppm.
P r ep a r a tion of (µ-p-MeC6H4S)(µ-MeS)[F e2(CO)6]3(µ4-
S)2(14). To the [MgBr]+ salt of the anion (µ-p-MeC6H4S)(µ-
S-)[Fe2(CO)6]3(µ4-S)2, prepared similarly from the [MgBr]+ salt
of the anion {(µ-p-MeC6H4S)(µ-CO)[Fe2(CO)6]2(µ4-S)}- and µ-S2-
Fe2(CO)6, was added 0.10 mL (1.6 mmol) of MeI at room
temperature, and the new mixture was stirred for 14 h.
Through the same workup as for 13, 0.252 g (47%) of 14 was
orange-red solid. Mp: 78-79 °C. Anal. Calcd for C27H14
-
Fe4O12S4: C, 36.76; H, 1.60. Found: C, 37.02; H, 1.69. IR (KBr
obtained as a red solid. Mp: 171 °C dec. Anal. Calcd for C26H10
-
disk): νCtO 2082 (s), 2057 (vs), 2033 (vs), 1992 (vs); νCdS 1014
(m) cm-1 1H NMR (CDCl3): 2.29 (s, 3H, CH3), 4.41 (q, AB
.
Fe6O18S4: C, 29.09; H, 0.94. Found: C, 29.10; H, 0.90. IR (KBr
1
disk): νCtO 2041 (vs), 1987 (vs) cm-1. H NMR (CDCl3): 2.21
pattern, 2H, CH2), 7.01-7.33 (m, 9H, C6H5, C6H4) ppm.
P r ep a r a tion of (µ-P h S)(µ-MeSCdS)[F e2(CO)6]2(µ4-S)
(12). To the [MgBr]+ salt of the anion {(µ-PhS)(µ-CO)[Fe2-
(CO)6]2(µ4-S)}-, prepared similarly from PhMgBr/Et2O, µ-S2-
Fe2(CO)6, and Fe3(CO)12, was added 0.10 mL (1.8 mmol) of CS2.
(s, 3H, CH3), 2.28 (s, 3H, SCH3), 7.02-7.24 (m, 4H, C6H4) ppm.
P r ep a r a tion of (µ-p-MeC6H4S)(µ-EtS)[F e2(CO)6]3(µ4-S)2
(15). To the [MgBr]+ salt of the anion (µ-p-MeC6H4S)(µ-S-)-
[Fe2(CO)6]3(µ4-S)2, prepared similarly as described above, was

Double- and Triple-Butterfly Fe/ S Cluster Complexes
Organometallics, Vol. 19, No. 19, 2000 3915
added 0.12 mL (1.5 mmol) of EtBr at room temperature, and
the new mixture was stirred for 14 h. Through the same
workup as for 13, 0.164 g (30%) of 15 was obtained as a red
solid. Mp: 118-120 °C. Anal. Calcd for C27H12Fe6O18S4: C,
29.81; H, 1.11. Found: C, 29.94; H, 0.96. IR (KBr disk): νCtO
X-r a y Str u ctu r e Deter m in a tion s of 6, 8, a n d 16. Single
crystals of 6, 8, and 16 suitable for X-ray diffraction analyses
were grown by slow evaporation of their CH2Cl2/hexane
solutions at about 4 °C. Each crystal was mounted on a Rigaku
AFC5R or a Bruker SMART 1000 automated diffractometer
equipped with a graphite monochromator with Mo KR radia-
tion (λ ) 0.710 69 or 0.710 73 Å). Details of the crystal data,
data collection, and structure refinements are summarized in
Table 4.
The structures were solved by direct methods and expanded
by Fourier techniques. The final refinements were accom-
plished by the full-matrix least-squares method with aniso-
tropic thermal parameters for non-hydrogen atoms. The
calculations were performed using the TEXSAN crystal-
lographic software package of Molecular Structure Corp. for
6 and 16 and using the SHELXTL-97 program for 8.
1
2043 (vs), 1993 (vs) cm-1. H NMR (CDCl3): 1.42 (t, J ) 7.0
Hz, 3H, CH3), 2.28 (s, 3H, p-CH3), 2.53 (q, J ) 7.0 Hz, 2H,
CH2), 7.02, 7.06, 7.21, 7.24 (q, A2B2 pattern, 4H, C6H4) ppm.
P r ep a r a tion of (µ-P h CH2S)2[F e2(CO)6]3(µ4-S)2 (16). The
solution of the [MgBr]+ salt of the anion {(µ-PhCH2S)(µ-CO)-
[Fe2(CO)6]2(µ4-S)}- was prepared from PhCH2MgBr/Et2O, µ-S2-
Fe2(CO)6, and Fe3(CO)12, according to a procedure similar to
that for the [MgI]+ salt of {(µ-MeS)(µ-CO)[Fe2(CO)6]2(µ4-S)}-
described above, and then was cooled to -78 °C using a dry
ice/acetone bath. To this solution was added 0.172 g (0.5 mmol)
of µ-S2Fe2(CO)6, and then the mixture was stirred for 2 h at
this temperature to give the [MgBr]+ salt of the anion
(µ-PhCH2S)(µ-S-)[Fe2(CO)6]3(µ4-S)2. After the mixture was
warmed to room temperature, 0.18 mL (1.5 mmol) of PhCH2-
Br was added and the new mixture was stirred for 14 h.
Solvent was removed under reduced pressure. The residue was
subjected to TLC separation using petroleum ether as eluent.
From the main red band 0.328 g (57%) of 16 was obtained as
a red solid. Mp: 175 °C dec. Anal. Calcd for C32H14Fe6O18S4:
C, 33.43; H, 1.23. Found: C, 33.12; H, 1.23. IR (KBr disk):
Ack n ow led gm en t. We are grateful to the National
Natural Science Foundation of China and the Labora-
tory of Organometallic Chemistry for financial support.
Su p p or tin g In for m a tion Ava ila ble: Full tables of crystal
data, atomic coordinates and thermal parameters, and bond
lengths and angles, in CIF format, for 6, 8 and 16. This
material is available free of charge via the Internet at http://
pubs. acs.org.
1
νCtO 2041 (vs), 1988 (vs) cm-1. H NMR (CDCl3): 3.66 (q, AB
pattern, 4H, 2CH2), 7.33 (s, 10H, 2C6H5) ppm.
OM0002071