Unexpected reactions of anionic intermediates [(μ-RE)(μ-S=CS)Fe2(CO)6]- with so2Cl2. Synthesis and characterization of novel dithioformato-bridged double clusters [(μ-RE)Fe2(CO)6]2(μ-S=CS-μ) (E = S, Se)

Article abstract of DOI:10.1021/om960775+

The dithioformato-bridged anionic salts [Et₃NH][(μ-RE)(μ-S=CS)Fe₂(CO)₆], generated from CO-bridged anionic complexes [Et₃NH][μ-RE)(μ-CO)Fe₂(CO)₆] and carbon disulfide, reacted in situ with SC₂Cl₂ in THF to afford a series of novel dithioformato-bridged double clusters [(μ-RE)Fe₂(CO)₆]₂(μ-S=CS-μ) (3a-e) (3a, RE = EtS; 3b, n-PrS; 3c, t-BuS; 3d, PhSe; 3e, p-MeCe₆H₄Se). A single-crystal diffraction analysis of 3c was undertaken and has confirmed the proposed structure.

Full text of DOI:10.1021/om960775+

632
Organometallics 1997, 16, 632-635
Un exp ected Rea ction s of An ion ic In ter m ed ia tes
[(µ-RE)(µ-SdCS)F e2(CO)6]- w ith SO2Cl2. Syn th esis a n d
Ch a r a cter iza tion of Novel Dith iofor m a to-Br id ged Dou ble
Clu ster s [(µ-RE)F e2(CO)6]2(µ-SdCS-µ) (E ) S, Se)
Li-Cheng Song,* Chao-Guo Yan, and Qing-Mei Hu
Department of Chemistry, Nankai University, Tianjin 300071, China
Bo-Mu Wu and Thomas C. W. Mak
Department of Chemistry, The Chinese University of Hong Kong,
Shatin, New Territories, Hong Kong
Received September 9, 1996X
The dithioformato-bridged anionic salts [Et3NH][(µ-RE)(µ-SdCS)Fe2(CO)6], generated from
CO-bridged anionic complexes [Et3NH][µ-RE)(µ-CO)Fe2(CO)6] and carbon disulfide, reacted
in situ with SO2Cl2 in THF to afford a series of novel dithioformato-bridged double clusters
[(µ-RE)Fe2(CO)6]2(µ-SdCS-µ) (3a -e) (3a , RE ) EtS; 3b, n-PrS; 3c, t-BuS; 3d , PhSe; 3e,
p-MeC6H4Se). A single-crystal diffraction analysis of 3c was undertaken and has confirmed
the proposed structure.
Sch em e 1
In tr od u ction
In recent years, the Seyferth group and we have
reported the synthesis of dithioformato-bridged anionic
salts [Et3NH][(µ-RE)(µ-SdCS)Fe2(CO)6] (E ) S, Se) and
their reactions with various organic and organometallic
electrophiles.1,2 All the reactions of [(µ-RE)(µ-SdCS)-
Fe2(CO)6]- anions can be rationalized in terms of their
action as exo sulfur-centered nucleophiles to give cor-
responding dithioformato-bridged, neutral transition-
metal complexes in which the organic or organometallic
group has been attached to the exo sulfur atom of these
anions.1,2 As a continuation of this project, we further
investigated the reactivity of the anions [(µ-RE)(µ-
SdCS)Fe2(CO)6]- toward an inorganic electrophile SO2-
Cl2. Now, we describe the unexpected synthesis of the
dithioformato-bridged double clusters [(µ-RE)Fe2(CO)6]-
[µ-SdCS-µ) (E ) S, Se) from the reactions studied and
an X-ray diffraction analysis for one representative
cluster [(µ-t-BuS)Fe2(CO)6]2(µ-SdCS-µ).
RE)Fe2(CO)6]2(µ-SdCSSCdS-µ) (2a-e), which were orig-
inally expected to be formed in view of SO2Cl2 being a
good oxidative coupling reagent for sulfur-centered
anions such as (µ-RE)(µ-S)Fe2(CO)6 (E ) S, Se)3 (Scheme
1).
Clusters 3a -e have been characterized by C/H analy-
1
sis and IR and H NMR spectroscopy, as well as for 3c
Resu lts a n d Discu ssion
by an X-ray diffraction method. The IR spectra of 3a -e
showed three to four strong absorption bands in the
region of 1950-2100 cm-1 and one medium-absorption
band at around 980 cm-1. Apparently, the former bands
were attributed to terminal carbonyls attached to iron
atoms, whereas the latter was attributed to a thiocar-
bonyl CdS group in the bridged CS2 ligand. The CdS
As seen from the Experimental Section below, a
cherry-red THF solution of the anionic salts [Et3NH]-
[(µ-RE)(µ-SdCS)Fe2(CO)6] (1) was first generated by
reaction of an excess of CS2 and the CO-bridged anionic
salts [Et3NH][(µ-RE)(µ-CO)Fe2(CO)6] formed in situ
from Fe3(CO)12/REH/Et3N reagents (E ) S, Se). Then,
to this solution of the salts was added at 0 °C a given
amount of inorganic electrophile SO2Cl2 and a color
change to red-brown occurred. After the reaction mix-
ture had been stirred for 2 h from 0 °C to room
temperature followed by TLC separation, five CS2-
bridged clusters [(µ-RE)Fe2(CO)6]2(µ-SdCS-µ) (3a -e)
were obtained rather than (CS2)2-bridged clusters [(µ-
vibrational band in free CS2 is situated at 1533 cm-1
but in CS2 complexes it is usually shifted down to the
region of 860-1120 cm-1 4 Although the 1H NMR
,
.
spectra of 3a -e all exhibited the presence of their
respective organic groups R, the axial or equatorial
orientations of two R groups on the bridged E atoms5
could not be assigned in terms of their 1H NMR data.
X Abstract published in Advance ACS Abstracts, J anuary 1, 1997.
(1) Seyferth, D.; Womack, G. B.; Archer, C. M.; Fackler, J . P., J r.;
Marler, D. O. Organometallics 1989, 8, 443.
(2) Song, L.-C.; Yan, C.-G.; Hu, Q.-M.; Wang, R.-J .; Mak, T. C. W.
Organometallics 1995, 14, 5513.
(3) (a) Song, L.-C.; Yan, C.-G.; Hu, Q.-M.; Wang, R.-J .; Mak, T. C.
W.; Huang, X.-Y. Organometallics 1996, 15, 1535. (b) Seyferth, D.;
Kiwan, A. M. J . Organomet. Chem. 1985, 281, 111.
(4) Patin, H.; Magnani, G.; Mahe, C.; Le Marouille, J .-Y.; Southern,
T. G.; Benoit, A.; Grandjean, D. J . Organomet. Chem. 1980, 197, 315.
S0276-7333(96)00775-3 CCC: $14.00 © 1997 American Chemical Society

Dithioformato-Bridged Double Clusters
Organometallics, Vol. 16, No. 4, 1997 633
thiocarbonyl C(13)dS(1) is bridged to Fe(1) via a σ-bond
[Fe(1)-C(13) ) 1.942(4) Å] and to Fe(2) via the donation
of an unshared electron pair on S(1) [Fe(2)-S(1) )
2.295(1) Å]. The double bond C(13)dS(1) extends to
1.654(4) Å from the bond length of 1.554 Å in free CS2.7
This coordination mode of C(13)dS(1) in the bridging
S(2)C(13)dS(1) is the same as that in (µ-PhSe) (µ-
SdCSCH2Ph)Fe2(CO)6 (abbreviated as Psf hereafter).2
For Psf corresponding Fe(1)-C(13), Fe(2)-S(1), and
C(13)dS(1) are equal to 1.98(1), 2.307(5), and 1.63(1)
Å, respectively. However, the coordination mode of
sulfur atom S (2) in the bridging S(2)C(13)dS(1) of 3c
is completely different from corresponding S(2) in Psf;
that is, the S(2) of 3c is bridged to Fe(3) and Fe(4) of
another subcluster rather than bonded to the benzyl
group as in Psf. In 3c, the single bond C(13)-S(2)
equals 1.759(4) Å (corresponding C(13)-S(2) ) 1.71(2)
Å in Psf), which is slightly shorter than normal single
C-S bond.8 All the bond angles around C(13) are
114.0(2)° [(Fe(1)-C(13)-S(1)], 125.9(2)° [Fe(1)-C(13)-
S(2)], and 119.5(2)° [S(1)-C(13)-S(2)], which are close
to the theoretical value for a sp2-hybridized carbon atom.
It follows that this type of coordination of S(2)C(13)dS(1),
to our knowledge, is unprecedent in all the reported
transition metal complexes containing CS2 as a ligand.2,9
The six coordinated atoms or groups around each iron
atom display as a distorted octahedron. The Fe(1)-
Fe(2) distance of 2.620(1) Å in 3c is almost the same as
that of 2.648(3) Å in Psf 2 but slightly longer than the
Fe(3)-Fe(4) distance of 2.536(1) Å and the Fe-Fe
distance in double-bridged complexes containing two
identical alkylthio or arylthio bridges.10,11 While the
S(3) atom is symmetrically bridged to Fe(1) and Fe(2)
[Fe(1)-S(3) ) 2.256(1) Å, Fe(2)-S(3) ) 2.252(1) Å] in
one subcluster, S(2) and S(4) atoms in the other sub-
cluster are unsymmetrically bridged to Fe(3) and Fe(4)
[Fe(3)-S(2) ) 2.278(1) Å, Fe(4)-S(2) ) 2.257(1) Å;
Fe(3)-S(4) ) 2.256(1) Å, Fe(4)-S(4) ) 2.280(1) Å]. 3c
can be also viewed as consisting of two butterfly
subclusters Fe(1)Fe(2)S(1)C(13)S(3) and Fe(3)Fe(4)S(2)-
S(4) joined together through a bond of C(13)-S(2). The
dihedral angle between Fe(1)-Fe(2)-S(3) and Fe(1)-
Fe(2)-S(1)-C(13) is 90.6°, while that between Fe(3)-
Fe(4)-S(2) and Fe(3)-Fe(4)-S(4) is 81.2°. In addition,
from Figure 1 it can be intuitively seen that the
subcluster Fe(1)Fe(2)S(1)C(13)S(3) is bonded to S(2) by
an axial type of bond, whereas two tertiary butyl groups
are bound to S(3) and S(4) by an equatorial type of
bond.5
F igu r e 1. ORTEP view of 3c, drawn with 35% probability
ellipsoids.
Ta ble 1. Selected Bon d Len gth s (Å) for 3c
Fe(1)-Fe(2)
Fe(1)-C(1)
Fe(1)-C(2)
Fe(1)-C(3)
Fe(1)-C(13)
Fe(1)-S(3)
Fe(2)-C(4)
Fe(2)-C(5)
Fe(2)-C(6)
Fe(2)-S(1)
Fe(2)-S(3)
C(13)-S(1)
C(13)-S(2)
2.620(1)
1.828(5)
1.792(5)
1.800(5)
1.942(4)
2.256(1)
1.797(6)
1.773(5)
1.809(6)
2.295(1)
2.252(1)
1.654(4)
1.759(4)
Fe(3)-Fe(4)
Fe(3)-C(7)
Fe(3)-C(8)
Fe(3)-C(9)
Fe(3)-S(2)
Fe(3)-S(4)
Fe(4)-C(10)
Fe(4)-C(11)
Fe(4)-C(12)
Fe(4)-S(2)
Fe(4)-S(4)
S(3)-C(14)
S(4)-C(18)
2.536(1)
1.800(6)
1.774(5)
1.812(5)
2.278(1)
2.256(1)
1.802(5)
1.793(5)
1.775(6)
2.257(1)
2.280(1)
1.873(5)
1.871(5)
Ta ble 2. Selected Bon d An gles (d eg) for 3c
Fe(2)-Fe(1)-C(13)
C(13)-Fe(1)-S(3)
S(1)-Fe(2)-S(3)
Fe(4)-Fe(3)-S(4)
S(2)-Fe(4)-S(4)
Fe(1)-C(13)-S(2)
Fe(2)-S(1)-C(13)
Fe(3)-S(2)-C(13)
Fe(1)-S(3)-Fe(2)
Fe(2)-S(3)-C(14)
Fe(3)-S(4)-C(18)
77.3(1)
81.2
Fe(2)-Fe(1)-S(3)
Fe(1)-Fe(2)-S(3)
Fe(4)-Fe(3)-S(2)
S(2)-Fe(3)-S(4)
Fe(1)-C(13)-S(1)
S(1)-C(13)-S(2)
Fe(3)-S(2)-Fe(4)
Fe(4)-S(2)-C(13)
Fe(1)-S(3)-C(14)
Fe(3)-S(4)-Fe(4)
Fe(4)-S(4)-C(18)
54.4(1)
54.5(1)
55.6(1)
78.0(1)
114.0(2)
119.5(2)
68.0(1)
116.8(2)
122.9(2)
68.0(1)
125.6(1)
81.9(1)
56.5(1)
77.9(1)
125.9(2)
93.1(2)
114.8(1)
71.1(1)
122.7(2)
121.5(2)
At present we are not clear about the pathway for
formation of the bridged clusters 3a -e. Since SO2Cl2
is a good oxidative coupling reagent for various types
of sulfur-centered anions such as RS-,6 (µ-S-)2Fe2(CO)6,5
and (µ-RE)(µ-S-)Fe2(CO)6 (E ) S, Se),3 the reaction of
1 with SO2Cl2 might first give the unstable oxidative
coupling intermediate products 2a -e, which would then
afford the final products 3a -e by extrusion of one
molecule of CS2. However, this pathway is mainly
speculative and further work about the pathway still
remains to be done in the future.
In order to confirm the structures of 3a -e, an X-ray
crystallographic study of 3c was undertaken. The study
demonstrates that crystals of 3c consist of discrete
molecules of 3c separated by normal van der Waals
distances. The crystal structure of 3c is shown in
Figure 1. Selected bond lengths and angles are given
in Tables 1 and 2, respectively.
Finally, it is worth pointing out that clusters 3a -e
are the first examples of double clusters containing a
CS2 ligand bridged to four iron atoms. Other examples
involving a ligand to four iron atoms are well-known,
such as [(µ-PhSe)Fe2(CO)6]2 [(1,3-(µ-SdCSCH2)2C6H4],2
[(CO)4Fe]4(µ4-E) (E ) Ge,12 Sn,13 Pb14), [(µ-Cl)(CO)8Fe2-
(µ4-E)]Fe2(CO)6 (E ) P, As),15 [(CO)8Fe2 (µ4-As)]2Fe2-
(7) Butler, I. S.; Fenster, A. E. J . Organomet. Chem. 1974, 66, 161.
(8) Patin, H.; Mignani, G.; Mahe, C.; Le Marouille, J .-Y.; Benoit,
A.; Grandjean, D. J . Organomet. Chem. 1980, 193, 93.
(9) (a) Yaneff, P. V. Coord. Chem. Rev. 1977, 23, 183. (b) Werner,
H. Coord. Chem. Rev. 1982, 43, 165. (c) Broadhust, P. V. Polyhedron
1985, 4, 1801.
As seen from Figure 1, 3c is composed of two identical
subcluster units (µ-t-BuS)Fe2(CO)6 and a bridging CS2
ligand. In the bridging S(2)C(13)dS(1) ligand the
(10) Le Borgne, G.; Grandjean, D.; Mathieu, R.; Poilblanc, R. J .
Organomet. Chem. 1977, 131, 429.
(11) Henslee, W.; Davis, R. E. Crystallogr. Struct. Commun. 1972,
1, 403.
(12) Melzer, D.; Weiss, E. J . Organomet. Chem. 1983, 255, 335.
(13) Lindley, P. F.; Woodward, P. J . Chem. Soc. A. 1967, 382.
(5) Seyferth, D.; Henderson, R. S.; Song, L.-C. Organometallics 1982,
1, 125.
(6) Tasker, H. S.; J ones, H. O. J . Chem. Soc. 1909, 95, 1910.

634 Organometallics, Vol. 16, No. 4, 1997
Song et al.
(CO)6,16 [(CO)8Fe2(µ4-Sb)]2Fe2(CO)6,17 [Fe(CO)4]4(µ4-E)3-
(EdSb,18 Bi19), [(µ-RE)Fe2(CO)6]2(µ4-E) (E ) S,20 Se3),
[(µ-RE)Fe2(CO)6](µ-SS-µ),3,4 and [(µ-RS)Fe2(CO)6]2(µ-Z-
µ) [Z ) S (CH2)4S,21 SCH2C6H4CH2S,22 SC(O)C6H4C-
(O)S,23 MeAsAsMe,24 C(O)C6H4C(O)25].
formato-bridged anionic salt [Et3NH][(µ-RE)(µ-SdCS)Fe2(CO)6]
(RE ) EtS) was made and then was cooled to 0 °C, to which
was added 0.10 mL (1.23 mmol) of sulfuryl chloride. The
reaction mixture was allowed to warm to room temperature
and stirred for additional 2 h. The solvent was removed in
vacuo to give a dark-red residue, which was extracted thor-
oughly with light petroleum ether. The extracts were concen-
trated and purified by TLC. Elution with petroleum ether
gave two red bands. The first red band gave 0.087 g (11%) of
(µ-EtS)2Fe2(CO)6, which was identified by comparison of its
melting point and 1H NMR spectrum with those given in the
literature.28 The second major red band gave 0.157 g (21%)
of [(µ-EtS)Fe2(CO)6]2(µ-SdCS-µ) (3a ) as a dark-red solid. Mp:
68-70 °C. Anal. Calcd for C17H10Fe4O12S4: C, 26.94; H, 1.33.
Found: C, 27.39; H, 1.36. IR: νCtO 2057 (s), 2041 (s), 1991
Exp er im en ta l Section
1. Gen er a l Com m en ts. All reactions were carried out
under an atmosphere of prepurified tank nitrogen. Tetrahy-
drofuran (THF) was distilled under nitrogen from sodium/
benzophenone ketyl, triethylamine from potassium hydroxide,
carbon disulfide from calcium chloride. Ethyl, n-propyl, and
t-butyl mercaptans, and sulfuryl chloride were of commercial
origin and used without further purification. Triiron dodeca-
carbonyl,26 benzeneselenol27 and 4-methylbenzeneselenol27
were prepared by literature procedures.
The progress of reactions was monitored by thin-layer
chromatography (TLC). Products were purified by TLC (20
× 25 × 0.025 cm, silica gel G) and recrystallized from
deoxygenated, mixed solvents of CH2Cl2/petroleum ether.
Chromatography was completed without exclusion of atmo-
spheric oxygen and moisture. The eluents were light petro-
leum ether (60-90 °C) and methylene chloride, which were
chemical reagents and used without further purification. The
yields of products 3a -e were calculated based on starting
material Fe3(CO)12.
(vs), 1957 (s), νCdS 982 (m) cm-1 1H NMR: δ 1.08-1.64 (m,
.
6H, 2CH3), 2.16-2.76 (m, 4H, 2CH2) ppm.
3. P r ep a r a tion of 3b. The same procedure as for 3a was
followed, but 0.19 mL (2.00 mmol) of n-propyl mercaptan was
used instead of ethyl mercaptan. The first red band gave 0.082
g (10%) of (µ-n-PrS)2Fe2(CO)6.28 The second red band gave
0.102 g (13%) of [(µ-n-PrS)2Fe2(CO)6]2(µ-SdCS-µ) (3b) as a
dark-red solid. Mp: 74-75 °C. Anal. Calcd for C19H14
Fe4O12S4: C, 29.04; H, 1.79. Found: C, 29.24; H, 1.72. IR:
νCtO 2057 (s), 2008 (vs), 1983 (vs), νCdS 982 (m) cm-1 1H
-
.
NMR: δ 0.76-1.28 (m, 6H, 2CH3), 1.44-1.82 (m, 4H, 2CH2),
2.16-2.64 (m, 4H, 2SCH2) ppm.
4. P r ep a r a tion of 3c. The same procedure as for 3a was
followed, but 0.22 mL (2.00 mmol) of t-butyl mercaptan was
used instead of ethyl mercaptan. The first red band gave very
slight (µ-t-BuS)2Fe2(CO)6.28 The second red band gave 0.232
g (29%) of [(µ-t-BuS)2Fe2(CO)6]2(µ-SdC-S-µ) (3c) as a dark-red
solid. Mp: 105-106 °C. Anal. Calcd for C21H18Fe4O12S4: C,
30.99; H, 2.23. Found: 31.25; H, 2.39. IR: νCtO 2057 (s), 2041
Melting points were determined on
a Yanaco MP-500
melting point apparatus and were uncorrected. Combustion
analysis was performed on a 240C model analyzer. 1H NMR
spectra were recorded on a J EOL FX-90Q spectrometer with
a CDCl3 solvent and a TMS internal standard. Infrared
spectra were obtained on a Nicolet FT-IR 5DX spectrometer
with a KBr disk.
(vs), 1991 (vs), 1967 (s), νCdS 990 (m) cm-1 1H NMR: δ 1.36,
.
2. P r ep a r a tion of 3a . A 100 mL three-necked flask
equipped with a stir bar, a N2 inlet tube, and serum caps was
charged with 1.00 g (1.98 mmol) of Fe3(CO)12 and 30 mL of
THF. To the resulting green solution were added 0.28 mL
(2.00 mmol) of triethylamine and 0.15 mL (2.00 mmol) of ethyl
mercaptan. The solution was stirred at room temperature for
30 min, during which time the solution turned red-brown and
the CO-bridged anionic salt [Et3NH][µ-RE)(µ-CO)Fe2(CO)6]
(RE ) EtS) was formed. To this solution was added 0.36 mL
(6.0 mmol) of carbon disulfide, and the new solution was
stirred for an additional 30 min. The solution turned cherry-
red, and IR spectroscopy showed that the [Et3NH][(µ-RE)(µ-
CO)Fe2(CO)6] (RE ) EtS) salt had been consumed since the
µ-CO frequency at 1743 cm-1 had disappeared.1 The dithio-
1.44 (s, s, 2 (CH3)3) ppm.
5. P r ep a r a tion of 3d . The same procedure as for 3a was
followed, but 0.21 mL (2.00 mmol) of benzeneselenol was used
instead of ethyl mercaptan. J ust like the case for the prepara-
tion of 3a , after addition of CS2 to the CO-bridged anionic salt
[Et3NH][(µ-RE)(µ-CO)Fe2(CO)6] (RE ) PhSe) for 30 min, the
solution turned cherry-red and IR spectroscopy showed the
µ-CO frequency of the salt at 1740 cm-1 had disappeared.29 It
indicated that the dithioformato-bridged anionic salt [Et3NH]-
[(µ-RE)(µ-SdCS)Fe2(CO)6] (RE ) PhSe) was formed. The first
red band gave 0.355 g (30%) of (µ-PhSe)2Fe2(CO)6.29 The
second red band gave 0.133 g (14%) of [(µ-PhSe)2Fe2(CO)6]2-
(µ-SdCS-µ) (3d ) as a brown-red solid. Mp: 138 °C (dec). Anal.
Calcd for C25H10Fe4O12S2Se2: C, 31.68; H, 1.06. Found: C,
31.81; H, 1.13. IR: νCtO 2065 (s), 2041 (s), 1991 (vs), νCdS 974
(m) cm-1 1H NMR: δ 7.16 (s, 10H, 2C6H5) ppm.
.
(14) Whitmire, K. H.; Lagrone, C. B.; Churchill, M. R.; Fettinger, J .
C.; Robinson, B. H. Inorg. Chem. 1987, 26, 3491.
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R.-J .; Wang, H.-G. J . Organomet. Chem. 1988, 340, 239. (c) Song, L.-
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Organomet. Chem. 1991, 412, C19.
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Chinese Univ. 1995, 16, 905.
6. P r ep a r a tion of 3e. The same procedure as for 3a was
followed, except that 0.342 g (2.00 mmol) of 4-methylbenzen-
eselenol was used instead of ethyl mercaptan. The first red
band gave 0.362 g (30%) of (µ-p-CH3C6H4Se)2Fe2(CO)6.2 The
second red band gave 0.072 g (8%) of [(µ-p-CH3C6H4Se)2Fe2-
(CO)6]2(µ-SdCS-µ) as a brown-red solid. Mp: 56-58 °C. Anal.
Calcd for C27H14Fe4O12S2Se2: C, 33.23; H, 1.45. Found: C,
33.02; H, 1.38. IR: νCtO 2065 (vs), 2041 (vs), 2000 (vs), νCdS
974 (m) cm-1 1H NMR: δ 2.20 (s, 6H, 2CH3), 6.84-7.28 (m,
.
8H, 2C6H4) ppm.
7. X-r a y Cr ysta llogr a p h y of 3c. Details of crystal
parameters, data collection, and structure refinement are
listed in Table 3. Raw intensities were collected on a Rigaku
AFC7R diffractometer with a rotating anode source (50 kV,
150 mA) at room temperature (293 K). Patterson superposi-
tion yielded the positions of all non-hydrogen atoms, which
were subjected to anisotropic refinement. All hydrogens were
(26) King, R. B. Transition-Metal Compounds. Organometallic
Syntheses; Academic Press: New York, 1965; Vol, I, p 95.
(27) Foster, D. G. Organic Syntheses; Wiley: New York, 1955;
Collect. Vol. III, p 771.
(28) De Beer, J . A.; Haines, R. J . J . Organomet. Chem. 1970, 24,
757.
(29) Song, L.-C.; Yan, C.-G.; Hu, Q.-M.; Wang, R.-J .; Wang, H.-G.
Acta Chim. Sin. 1995, 53, 402.

Dithioformato-Bridged Double Clusters
Organometallics, Vol. 16, No. 4, 1997 635
assigned the same isotropic temperature factors (µ ) 0.08 Å2)
and included in the structure factor calculations. Computa-
tions were performed using the SHELXTL PC program pack-
age on a PC 486 computer. Analytical expressions of atomic
scattering factors were employed, and anomalous dispersion
corrections were incorporated.30
Ta ble 3. Cr ysta l Da ta Collection a n d Refin em en t
for 3c
mol formula
mol wt
cryst syst
space group
a/Å
C21H18O12S4Fe4
813.99
monoclinic
P21/c
14.529(3)
b/Å
9.270(2)
c/Å
23.847(3)
96.780(10)
3189.3
4
1.695
1632
Rigaku AFC7R
20
Ack n ow led gm en t. We are grateful to the National
Natural Science Foundation of China, the State Key
Laboratory of Structural Chemistry, and the Laboratory
of Organometallic Chemistry for financial support of
this project.
â/deg
V/Å3
Z
Dc/g cm-3
F(000)
diffractometer
temp/°C
radiation
graphite-monochromatized
Mo KR, λ ) 0.0710 73 Å
Su p p or tin g In for m a tion Ava ila ble: Text describing
X-ray procedures and tables of crystallographic data, positional
and thermal parameters including hydrogen atoms, and aniso-
tropic parameters (7 pages). Ordering information is given
on any current masthead page.
scan type
2θmax/deg
no. observns, n
no. variables, p
RF ) ∑||Fo| - |Fo||/∑|Fo|
ω scan
55
4494
371
0.039
Rw ) [∑W2(|Fo| - |Fc|)2/∑W2|Fo| ]1/2 0.050
2
S ) [∑W(|Fo| - |Fc|)2/(n - p)]1/2
1.14
0.001
OM960775+
largest ∆/σ in final cycle
largest peak in final diff map/e Å-3 0.35
(30) International Tables for X-ray Crystallography; Kynoch Press:
Birmingham, U.K., 1974 (now distributed by Kluwer: Dordrecht, The
Netherlands); Vol. 4, pp 55, 99, 149.
generated geometrically (C-H bonds fixed at 0.96 Å) and
allowed to ride on their respective parent C atoms; they were