Unexpected preparation of butterfly Fe/S cluster complexes containing a quaternary phosphorus atom via reactions of the anions (μ-RS)(μ-S -)Fe2(CO)6 and (μ-RS) (μ-S -)[Fe2(CO)6]2(μ4-S) with diphenylchlorophosphine

Article abstract of DOI:10.1021/om049372x

Six new butterfly Fe/S cluster complexes, (μ-RS)(η ¹-Ph₂PS-η¹)[Fe₂(CO) ₆] (3, R = Me; 5, R = Ph), (μ-RS)(η¹-Ph ₂PS-η¹)[Fe₂(CO)₅(Ph ₂PY)] (4, R=Me, Y = Cl; 6,R = Y = Ph), and (μ-RS) (η ¹-Ph₂PS-η²) [Fe₂(CO) ₆] (μ₄-S)[Fe₂(CO)₅] (7, R = n-Bu; 8, R = Ph), were unexpectedly prepared by a one-pot synthetic method involving reactions of the in situ generated S-centered monoanions (μ-RS)(μ-S^-)Fe₂(CO)₆ (1) and (μ-RS)(μS^-). (Fe₂(CO)₆]₂ (μ₄-S) (2) with Ph₂PCl. While the possible mechanisms for the unexpected reactions are suggested, the structures of products 3-8 have been fully characterized.

Full text of DOI:10.1021/om049372x

16
Organometallics 2005, 24, 16-19
Unexpected Preparation of Butterfly Fe/S Cluster
Complexes Containing a Quaternary Phosphorus Atom
via Reactions of the Anions (µ-RS)(µ-S-)Fe2(CO)6 and
(µ-RS)(µ-S-)[Fe2(CO)6]2(µ4-S) with
Diphenylchlorophosphine
Li-Cheng Song,* Guang-Huai Zeng, Qing-Mei Hu, Jian-Hua Ge, and
Shao-Xia Lou
Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry,
Nankai University, Tianjin 300071, People’s Republic of China
Received August 13, 2004
Scheme 1
Summary: Six new butterfly Fe/S cluster complexes,
(µ-RS)(η1-Ph2PS-η1)[Fe2(CO)6] (3, R ) Me; 5, R ) Ph),
(µ-RS)(η1-Ph2PS-η1)[Fe2(CO)5(Ph2PY)] (4, R ) Me, Y )
Cl; 6, R ) Y ) Ph), and (µ-RS)(η1-Ph2PS-η2)[Fe2(CO)6]-
(µ4-S)[Fe2(CO)5] (7, R ) n-Bu; 8, R ) Ph), were unex-
pectedly prepared by a “one-pot” synthetic method in-
volving reactions of the in situ generated S-centered
monoanions (µ-RS)(µ-S-)Fe2(CO)6 (1) and (µ-RS)(µ-S-)-
[Fe2(CO)6]2(µ4-S) (2) with Ph2PCl. While the possible
mechanisms for the unexpected reactions are suggested,
the structures of products 3-8 have been fully character-
ized.
phosphorus-based electrophile. As a result, although the
expected cluster phosphines were not obtained, a series
of unexpected butterfly Fe/S cluster complexes, each
containing an Fe atom bonded quaternary phosphorus
atom, namely (µ-RS)(η1-Ph2PS-η1)[Fe2(CO)6] (3, 5),
(µ-RS)(η1-Ph2PS-η1)[Fe2(CO)5(Ph2PY)] (4, 6), and (µ-RS)-
(η1-Ph2PS-η2)[Fe2(CO)6](µ4-S) [Fe2(CO)5] (7, 8), were
isolated and fully characterized (Scheme 1).
As a typical experiment, the reaction of anion 1 (R )
Me) with Ph2PCl to produce the single-butterfly com-
plexes 3 and 4 was performed as follows. To the green
solution of the IMg derivative of anion 1 (R ) Me),
prepared from 0.344 g (1 mmol) of (µ-S2)Fe2(CO)6, ca. 1
mmol of the Grignard reagent MeMgI, and 20 mL of
THF at -78 °C,3a was added 0.2 mL (1 mmol) of
Ph2PCl, resulting in a color change to red. The mixture
was stirred at -78 °C for 15 min and then 30 min at
room temperature. Solvent was removed at reduced
pressure, and the residue was subjected to TLC on silica
gel 60H. Elution with CH2Cl2/petroleum ether (1/4 v/v)
gave an orange-red band and a brown-red band, from
which 3 and 4 were obtained in 58% and 10% yields,
respectively. Similarly, when PhMgBr was used instead
of MeMgI, 5 and 6 were isolated in 63% and 20% yields,
respectively.
Butterfly iron-sulfur cluster complexes have drawn
increased attention, largely due to their unique struc-
tures and novel reactivities,1 as well as the closely
related biological relevance to the active site of the
Fe-only hydrogenases.2 Among such complexes, the
butterfly S-centered anions (µ-RS)(µ-S-)Fe2(CO)6 (1) and
(µ-RS)(µ-S-)[Fe2(CO)6]2(µ4-S) (2) are of particular inter-
est, since they have become important synthons for
preparing a variety of single-, double-, and multiple-
butterfly cluster complexes.3,4 To develop the new
chemistry of these two anions and to prepare the
corresponding Fe/S cluster core containing phosphines,5
we carried out reactions of the in situ generated anions
1 and 2 with diphenylchlorophosphine, a common
* To whom correspondence should be addressed. Fax: 0086-22-
23504853. E-mail: lcsong@nankai.edu.cn.
(1) For example, see: (a) Ogino, H.; Inomata, S.; Tobita, H. Chem.
Rev. 1998, 98, 2093. (b) Seyferth, D.; Song, L.-C.; Henderson, R. S. J.
Am. Chem. Soc. 1981, 103, 5103. (c) Seyferth, D.; Henderson, R. S.;
Song, L.-C. Organometallics 1982, 1, 125. (d) Bose, K. S.; Sinn, E.;
Averill, B. A. Organometallics 1984, 3, 1126. (e) Song, L.-C.; Fan, H.-
T.; Hu, Q.-M. J. Am. Chem. Soc. 2002, 124, 4566. (f) Song, L.-C.; Gong,
F.-H.; Meng, T.; Ge, J.-H.; Cui, L.-N.; Hu, Q.-M. Organometallics 2004,
23, 823.
(2) For example, see: (a) Gloaguen, F.; Lawrence, J. D.; Rauchfuss,
T. B. J. Am. Chem. Soc. 2001, 123, 9476. (b) Darensbourg, M. Y.; Lyon,
E. J.; Smee, J. J. Coord. Chem. Rev. 2000, 206-207, 533. (c) Ott, S.;
Kritikos, M.; A° kermark, B.; Sun, L. Angew. Chem., Int. Ed. 2003, 42,
3285. (d) Song, L.-C.; Yang Z.-Y.; Bian, H.-Z.; Hu, Q.-M. Organome-
tallics 2004, 23, 3082.
Products 3-6 have been fully characterized by el-
emental analysis, spectroscopy,6 and X-ray diffraction
(3) For example, see: (a) Seyferth, D.; Henderson, R. S.; Song, L.-
C. Womack, G. B. J. Organomet. Chem. 1985, 292, 9. (b) Song, L.-C.;
Hu, Q.-M.; Fan, H.-T.; Sun, B.-W.; Tang, M.-Y.; Chen, Y.; Sun, Y.; Sun,
C.-X.; Wu, Q.-J. Organometallics 2000, 19, 3909.
(4) For example, see: (a) Song, L.-C.; Lu, G.-L.; Hu, Q.-M.; Fan, H.-
T.; Chen, Y.; Sun, J. Organometallics 1999, 18, 3258. (b) Song, L.-C.;
Lu, G.-L.; Hu, Q.-M.; Sun, J. Organometallics 1999, 18, 5429. (c) Wang,
Z.-X.; Jia, C.-S.; Zhou, Z.-Y.; Zou, X.-G. J. Organomet. Chem. 2000,
601, 108.
(5) The attempted preparation of such phosphines was originally
due to our need for further preparation of novel fullerene complexes
that contain transition-metal cluster cores. For preparation of fullerene
complexes that contain mononuclear metal phosphines such as a dppf
ligand, see our following papers: (a) Song, L.-C.; Liu, J.-T.; Hu, Q.-
M., Wang, G.-F.; Zanello, P.; Fontani, M. Organometallics 2000, 19,
5342. (b) Song, L.-C.; Wang, G.-F.; Liu, P.-C.; Hu, Q.-M. Organome-
tallics 2003, 22, 4593.
10.1021/om049372x CCC: $30.25 © 2005 American Chemical Society
Publication on Web 12/08/2004

Communications
Organometallics, Vol. 24, No. 1, 2005 17
Figure 1. Molecular structure of 3. Selected bond lengths
(Å) and angles (deg): Fe(1)-S(2) ) 2.237(2), Fe(1)-S(1) )
2.3541(19), Fe(2)-P(1) ) 2.2600(19), Fe(2)-S(2) ) 2.2540-
(19), P(1)-S(1) ) 2.030(2), Fe(1)-Fe(2) ) 2.6431(16);
S(2)-Fe(1)-S(1) ) 85.84(7), S(1)-Fe(1)-Fe(2) ) 85.21(5),
S(2)-Fe(2)-P(1) ) 86.36(7), P(1)-Fe(2)-Fe(1) ) 79.00(5),
Fe(1)-S(2)-Fe(2) ) 72.11(7), S(1)-P(1)-Fe(2) ) 104.26-
(8), P(1)-S(1)-Fe(1) ) 90.90(8).
Figure 2. Molecular structure of 6. Selected bond lengths
(Å) and angles (deg): Fe(1)-S(1) ) 2.3551(19), Fe(1)-
Fe(2) ) 2.668(2), Fe(1)-S(2) ) 2.2464(18), Fe(1)-P(2) )
2.279(2), Fe(2)-P(1) ) 2.256(2), Fe(2)-S(2) ) 2.272(2),
P(1)-S(1)
) 2.033(2); S(2)-Fe(1)-P(2) ) 112.38(7),
S(2)-Fe(1)-S(1) ) 82.53(7), P(2)-Fe(1)-S(1) ) 90.61(7),
S(2)-Fe(1)-Fe(2) ) 54.25(5), S(1)-P(1)-Fe(2) ) 104.68-
(8), P(1)-S(1)-Fe(1) ) 90.86(8).
analysis.7 Figures 1 and 2 show the molecular structures
of 3 and 6 with their selected bond lengths and angles,
respectively. As can be seen in Figures 1 and 2, both 3
and 6 consist of the butterfly cluster core Fe(1)Fe(2)-
S(1)P(1)S(2), in which the P(1) atom has two phenyl
substituents. However, while 3 contains Fe(1) and
Fe(2) atoms each bonded to three terminal CO ligands,
6 has Fe(2) bound to three terminal CO ligands and
Fe(1) attached to two terminal CO ligands and one Ph3P
ligand. In addition, the S(2) atom of 3 is bonded to an
equatorial methyl group, whereas S(2) of 6 is attached
to an equatorial phenyl group.8 Therefore, the crystal
and molecular structures of 3 and 6 are in good agree-
ment with the elemental analysis and spectroscopic data
of 3-6, respectively. For instance, the IR spectra of 3-6
displayed four or five absorption bands in the region
2074-1932 cm-1 for their terminal carbonyls, whereas
the 31P NMR spectrum of 3 or 5 showed a singlet at
44-67 ppm for its P atom in the SPPh2 group and that
of 4 or 6 displayed a singlet at 58-71 ppm for its P atom
in the SPPh2 group. In addition, the 31P NMR spectra
of 4 and 6 each exhibited another singlet at ca. 70 and
ca. 150 ppm for the P atom in the PPh3 and Ph2PCl
ligands, respectively. It is worth pointing out that 3-6
are the first examples of butterfly FeSP cluster com-
plexes with one triangular Fe(1)Fe(2)S(2) wing and one
tetragonal Fe(1)Fe(2)S(1)P(1) wing, although numerous
butterfly FeSP cluster complexes are known to have two
triangular wings, such as (µ-Ph2P)(µ-RS)Fe2(CO)6 (R )
Ph,9 C6H1110), [µ-Ph(Cl)P](µ-t-BuS)Fe2(CO)6,11 and (µ-
Me2P)(µ-t-BuS)Fe2(CO)6.12 It is due to such a striking
difference in wing structures of these two types of but-
terfly FeSP cluster complexes that the geometric pa-
rameters involved in their cluster cores are so different.
As exemplified by 3 and (µ-Me2P)(µ-t-BuS)Fe2(CO)6,12
such differences can be clearly seen from the fol-
lowing geometric parameters (for the latter complex
the corresponding values are given in parentheses):
Fe(1)-Fe(2) ) 2.6437 (2.585), Fe(1)-S(2) ) 2.237
(2.273), Fe(2)-S(2) ) 2.254 (2.267), Fe(2)-P(1) ) 2.260
(2.216, 2.229) Å; Fe(1)-S(2)-Fe(2) ) 72.11 (69.4)°.
As another typical experiment, the sequential reaction
of anion 2 (R ) n-Bu) with Ph2PCl to afford the double-
butterfly complex 7 was carried out as described below.
Treatment of the Li derivative of the anion [(µ-RS)-
(µ-CO)Fe2(CO)6]- (R ) n-Bu), prepared from 0.50 g (1
mmol) of Fe3(CO)12, 0.12 mL (1 mmol) of n-BuSH, and
1 mmol of n-BuLi in 20 mL of THF, with 0.344 g (1
(6) Characterization data are as follows. 3: mp 113-114 °C. Anal.
Calcd for C19H13Fe2O6PS2: C, 41.91; H, 2.39. Found: C, 41.99; H, 2.17.
IR (KBr disk): νCtO 2064 (vs), 2021 (vs), 2003 (vs), 1998 (vs), 1966 (s)
cm-1 1H NMR (200 MHz, CDCl3): δ 2.59 (s, 3H, CH3), 7.31-7.76 (m,
.
10H, 2C6H5). 31P NMR (81.0 MHz, CDCl3, H3PO4): δ 66.72 (s). 4: mp
121-122 °C. Anal. Calcd for C30H23ClFe2O5P2S2: C, 48.88; H, 3.12.
Found: C, 48.51; H, 2.96. IR (KBr disk): νCtO 2047 (vs), 1986 (vs),
1962 (vs), 1942 (s) cm-1 1H NMR (200 MHz, CDCl3): δ 2.12 (s, 3H,
.
CH3), 7.27-7.84 (m, 20H, 4C6H5). 31P NMR (81.0 MHz, CDCl3, H3-
PO4): δ 70.76 (s, SPPh2), 151.72 (s, ClPPh2). 5: mp 112-113 °C. Anal.
Calcd for C24H15Fe2O6PS2: C, 47.55; H, 2.49. Found: C, 47.69; H, 2.73.
IR (KBr disk): νCtO 2068 (vs), 2038 (vs), 2018 (vs), 1999 (vs), 1981
(vs) cm-1 1H NMR (200 MHz, CDCl3): δ 7.25-7.83 (m, 15H, 3C6H5).
.
31P NMR (81.0 MHz, CDCl3, H3PO4): δ 44.55 (s). 6: mp 126-127 °C.
Anal. Calcd for C41H30Fe2O5P2S2‚CH2Cl2: C, 54.49; H, 3.46. Found: C,
54.59; H, 3.47. IR (KBr disk): νCtO 2040 (vs), 1982 (vs), 1951 (vs), 1932
(s) cm-1 1H NMR (200 MHz, CDCl3): δ 5.29 (s, 2H, CH2Cl2), 6.97-
.
7.76 (m, 30H, 6C6H5). 31P NMR (81.0 MHz, CDCl3, H3PO4): δ 58.76 (s,
SPPh2), 70.40 (s, PPh3).
(7) Crystal data are as follows. 3: monoclinic, space group C2/c, a
) 20.697(9) Å, b ) 9.741(4) Å, c ) 22.862(10) Å, â ) 109.674(6)°, F(000)
) 2192, V ) 4340(3) Å3, Z ) 8, Dc ) 1.665 g cm-3, µ(Mo KR) ) 1.636
mm-1, R ) 0.0694, Rw ) 0.0660, GOF ) 1.008. 6: triclinic, space group
P1h, a ) 10.074(9) Å, b ) 13.125(12) Å, c ) 15.977(14) Å, R ) 15.977-
(14)°, â ) 83.658(16)°, γ ) 89.174(17)°, F(000) ) 944, V ) 2092(3) Å3,
(9) Job, B. E.; McLean, R. A. N.; Thompson, D. T. J. Chem. Soc.,
Chem. Commun. 1966, 895.
(10) Winter, A.; Zsolnai, L.; Huttner, G. J. Organomet. Chem. 1983,
250, 409.
Z ) 2, Dc ) 1.469 g cm-3, µ(Mo KR) ) 1.041 mm-1, R ) 0.0585, Rw
0.1334, GOF ) 0.977.
)
(11) Song, L.-C.; Wang, R.-J.; Li, Y.; Wang, H.-G.; Wang, J.-T. Chin.
J. Org. Chem. 1989, 9, 512.
(8) Shaver, A.; Fitzpatrick, P. J.; Steliou, K.; Butler, I. S. J. Am.
Chem. Soc. 1979, 101, 1313.
(12) Song, L.-C.; Hu, Q.-M.; Zhou, Z.-Y.; Hu, G.-Z. Chin. J. Org.
Chem. 1991, 11, 533.

18 Organometallics, Vol. 24, No. 1, 2005
Communications
and Fe(3), as well as each of the two CO’s attached to
Fe(4), are terminal. Therefore, this type of structure is
consistent with the elemental analysis and spectroscopic
data of 7 and 8. For example, the IR spectra of 7 and 8
exhibited six absorption bands in the range 2080-1939
cm-1 typical of their terminal carbonyls, whereas the
31P NMR spectra of 7 and 8 each displayed a singlet at
ca. 162 ppm for their P atoms in SPPh2 groups. It is
noteworthy that these chemical shifts of the P atoms of
7 and 8 are considerably larger than those of the
corresponding P atoms in 3-6. Apparently, this is not
only due to the electron-withdrawing ability of Fe2(CO)5
and SFe2(CO)6 groups attached to the P atom in 7 and
8 being stronger than that of the corresponding Fe(CO)3
and SFe(CO)3 or SFe(CO)2(Ph2PY) groups in 3-6 but
also due to the effect of the ring size of the metallacycles,
i.e., a P-S-Fe-Fe four-membered ring in 3-6 and a
P-S-Fe-S-Fe five-membered ring in 7 and 8.15
Interestingly, complexes 7 and 8 are the first µ4-S-
containing double-butterfly Fe/S cluster complexes that
contain a group, here a Ph2P group, axially bonded to
the bridged µ-S atom of such clusters, while all the
reported µ4-S double-butterfly Fe/S cluster complexes,
such as [(µ-RS)Fe2(CO)6]2(µ4-S) (R ) Me,16 Et17), have
two R groups equatorially bonded to their µ-S atoms in
order to avoid the sterically strong repulsions with their
neighboring subclusters.4a,b The µ-S atom axially bonded
Ph2P group in clusters 7 and 8 is obviously stabilized
by coordination of the P atom of the Ph2P group to the
Fe atom of the neighboring Fe/S subcluster core.
At present, the mechanisms of the unexpected reac-
tions described above are not clear to us. However, on
the basis of the well-known nucleophilic reactivity of the
S-centered monoanions 13,18 and 2,4,19 we might suggest
that the reactions of anions 1 and 2 with Ph2PCl would
first give the expected butterfly Fe/S cluster phosphines
M1 and M2 by intermolecular nucleophilic substitution.
Then, 3 and 5 would be produced from M1 by intramo-
lecular nucleophilic attack of the P atom at iron with
displacement of mercaptide from iron, whereas 7 and 8
would be yielded from M2 by intramolecular nucleophilic
attack of the P atom at the iron atom of the neighboring
subcluster followed by loss of one CO ligand (Scheme
2). In addition, the minor products 4 and 6 most likely
would be produced through intermolecular nucleophilic
CO substitution of 3 and 5 with unreacted Ph2PCl and
Ph3P (formed in situ from Ph2PCl and the Grignard
reagent PhMgBr present in the sequential reaction
systems), respectively. In fact, the intramolecular or
intermolecular nucleophilic attack at iron followed by
loss of an Fe-bonded ligand in such butterfly Fe/S
cluster systems was previously well-documented.20
Figure 3. Molecular structure of 8. Selected bond lengths
(Å) and angles (deg): Fe(1)-S(3) ) 2.2490(14), Fe(1)-
Fe(4) ) 2.5409(12), Fe(1)-S(1) ) 2.2957(15), Fe(2)-S(3)
) 2.2433(14), Fe(2)-Fe(3) ) 2.5363(14), Fe(3)-S(3) )
2.2506(15), P(1)-S(2), ) 2.1694(17), P(1)-Fe(4) ) 2.2106-
(15); S(3)-Fe(1)-S(1) ) 76.05(5), S(3)-Fe(1)-Fe(4) )
55.12(4), S(3)-Fe(2)-S(2) ) 80.87(5), P(1)-Fe(4)-Fe(1) )
142.59(4), S(2)-P(1)-Fe(4) ) 112.02(6), P(1)-S(2)-Fe(3)
) 104.86(6).
mmol) of (µ-S2)Fe2(CO)6 at room temperature for 2 h
resulted in formation of a green solution of the Li
derivative of the S-centered anion 2 (R ) n-Bu).4a To
this green solution was added 0.2 mL (1 mmol) of
Ph2PCl at -78 °C, and this new mixture was stirred
for 15 min at -78 °C and then for 4 h at room
temperature to give a brown-red mixture. After the
same workup as that in the preparation of 3 and 4 but
using THF/petroleum ether (1/30 v/v) as eluent, a major
brown-red band developed, from which 7 was obtained
in 42% yield. Similarly, when PhSH was employed in
place of n-BuSH, 8 was afforded in 56% yield.
Products 7 and 8 were fully characterized by elemen-
tal analysis, spectroscopy,13 and X-ray crystallography.14
Figure 3 presents the molecular structure of 8 with
selected bond lengths and angles. It can be seen in
Figure 3 that (i) 8 comprises two butterfly subcluster
cores Fe(1)Fe(4)S(1)S(3) and Fe(2)Fe(3)S(2)S(3) joined
to a spiran type of µ4-S, namely the S(3) atom, (ii) the
S(1) atom is attached to the C(12) atom by an equatorial
type of bond, whereas the P(1) atom is attached to the
S(2) atom by an axial type of bond8 and attached to the
Fe(4) atom by a bond trans to the Fe(1)-Fe(4) bond,
and (iii) each of the three CO’s attached to Fe(1), Fe(2),
(13) Characterization data are as follows. 7: mp 162 °C dec. Anal.
Calcd for C27H19Fe4O11PS3: C, 37.24; H, 2.18. Found: C, 37.09; H, 2.29.
IR (KBr disk): νCtO 2079 (s), 2043 (vs), 2009 (vs), 1971 (s), 1958 (s),
(15) Lindner, E.; Fawzi, R.; Mayer, H. A.; Eichele, K.; Hiller, W.
Organometallics 1992, 11, 1033.
1939 (s) cm-1
.
1H NMR (200 MHz, CDCl3): δ 0.95 (t, J ) 7.2 Hz, 3H,
(16) Coleman, J. M.; Wojcicki, A.; Pollick, P. J.; Dahl, L. F. Inorg.
Chem. 1967, 6, 1236.
CH3), 1.44-1.58 (m, 2H, CH2CH3), 1.69-1.84 (m, 2H, SCH2CH2), 2.44-
2.76 (m, 2H, SCH2), 7.40-7.80 (m, 10H, 2C6H5). 31P NMR (81.0
MHz, CDCl3, H3PO4): δ 162.36 (s). 8: mp 167 °C dec. Anal. Calcd for
(17) Song, L.-C.; Kadiata, M.; Wang, J.-T.; Wang, R.-J.; Wang, H.-
G. J. Organomet. Chem. 1988, 340, 239.
C
29H15Fe4O11PS3: C, 39.10; H, 1.69. Found: C, 38.85; H, 1.90. IR (KBr
(18) (a) Seyferth, D.; Kiwan, A. M. J. Organomet. Chem. 1985, 286,
219. (b) Song, L.-C.; Kadiata, M.; Wang, J.-T.; Wang, R.-J.; Wang, H.-
G. J. Organomet. Chem. 1990, 391, 387. (c) Song, L.-C.; Yan, C.-G.;
Hu, Q.-M.; Wang R.-J.; Mak, T. C. W.; Huang, X.-Y. Organometallics
1996, 15, 1535. (d) Song, L.-C.; Hu, Q.-M.; Zhang, Q.-Y.; Feng, Q. Chin.
J. Org. Chem. 1988, 8, 213.
disk): νCtO 2080 (vs), 2043 (vs), 2015 (vs), 2003 (vs), 1988 (vs), 1942
(s) cm-1 1H NMR (200 MHz, CDCl3): δ 7.25-7.84 (m, 15H, 3C6H5).
.
31P NMR (81.0 MHz, CDCl3, H3PO4): δ 161.28 (s).
(14) Crystal data are as follows. 8: triclinic, space group P1h, a )
9.408(4) Å, b ) 10.438(4) Å, c ) 19.084(8) Å, R ) 91.396(7)°, â )
103.410(7)°, γ ) 106.192(6)°, F(000) ) 888, V ) 1742.7(12) Å3, Z ) 2,
Dc ) 1.696 g cm-3, µ(Mo KR) ) 1.913 mm-1, R ) 0.0482, Rw ) 0.1153,
GOF ) 0.985.
(19) (a) Song, L.-C.; Lu, G.-L.; Hu, Q.-M.; Yang, J.; Sun, J. J.
Organomet. Chem. 2001, 623, 56. (b) Wang, Z.-X.; Jia, C.-S.; Zhou, Z.-
Y.; Zhou, X.-G, J. Organomet. Chem. 1999, 580, 201.

Communications
Organometallics, Vol. 24, No. 1, 2005 19
Scheme 2
by removal of a ligand from Fe to give the originally
unexpected products 3/5 and 7/8, and (iii) further CO
substitution of 3 with Ph2PCl or of 5 with Ph3P that
were present in the reaction systems to afford 4 and 6.
To further understand the mechanistic details and the
scope/limits for reactions leading to complexes 3-8,
other butterfly Fe/S cluster anions, such as the dianions
1b
(µ-S-)2Fe2(CO)6 and (µ-S-)2[Fe2(CO)6]4(µ4-S)2(µ-SZS-
µ),21 as well as other phosphine halides and arsine
halides will be the subject of future studies in this
laboratory.
In conclusion, we have isolated and characterized the
six quaternary phosphorus atom coordinating butterfly
Fe/S cluster complexes 3-8, which were produced by a
“one-pot” synthetic method involving reactions of the in
situ formed anions 1 and 2 with Ph2PCl. Possible
pathways for formation of these new complexes have
been suggested, which involve three elementary steps:
(i) the intermolecular nucleophilic attack of the nega-
tively charged S atoms of 1 and 2 at the P atom of
Ph2PCl to give the expected intermediate cluster phos-
phines M1 and M2, (ii) the intramolecular nucleophilic
attack of the P atom in M1 or M2 at the Fe atom followed
Acknowledgment. We are grateful to the National
Natural Science Foundation of China and the Research
Fund for the Doctoral Program of Higher Education of
China for financial support.
Supporting Information Available: Text describing the
synthesis and characterization of complexes 3-8 and CIF files
giving the structural determinations of 3, 6 and 8, including
atomic coordinates, equivalent isotropic displacement param-
eters, bond lengths and angles, and data collection and
processing parameters. This material is available free of charge
via the Internet at http://pubs.acs.org.
OM049372X
(20) For example, see: (a) Seyferth, D.; Womack, G. B.; Song, L.-
C.; Cowie, M.; Hames, B. W. Organometallics 1983, 2, 928. (b) Song,
L.-C.; Hu, Q.-M.; Wang, J.-T. Chem. J. Chin. Univ. 1985, 6, 995. (c)
Hogarth, G. J. Organomet. Chem. 2003, 672, 29.
(21) Song, L.-C.; Fan, H.-T.; Hu, Q.-M.; Yang, Z.-Y.; Sun, Y.; Gong,
F.-H. Chem. Eur. J. 2003, 9, 170.