Synthesis and spectroscopic characterization of μ4-S-containing double- and triple-butterfly iron carbonyl complexes

Article abstract of DOI:10.1021/om011039v

We first investigated the nucleophilic reactivities of the complex anions [(μ-RTe)(μ-CO)Fe₂(CO)₆]^- (1), {(μ-RS)(μ-S-CS)[Fe₂(CO)₆]₂(μ₄ -S)}^- (3), and {(μ-RS)(μ-S)[Fe₂(CO)₆]₃(μ₄- S)₂}^- (5) toward the electrophiles SCl₂ and Cp(CO)₂FeI, respectively. Interestingly, while anions 1 undergo a new type of double nucleophilic substitution reaction with SCl₂ to give the series of one-μ₄-S-containing double-butterfly iron carbonyl complexes [(μ-RTe)Fe₂(CO)₃]₂(μ₄-S) (2a, R = Et; 2b, R = Ph; 2c, R = p-MeC₆H₄; 2d, R = o-MeC₆H₄; 2e, R = α-C₁₀H₇), the single nucleophilic substitution reactions of anions 3 and 5 with Cp(CO)₂FeI afford the one-,μ4-S-containing double-butterfly iron carbonyl complexes (μ-RS)[μ-Cp(CO)₂FeSC=S][Fe₂(CO)₆]₂ -(μ4-S) (4a, R = Me; 4b, R = Et; 4c, R = Ph; 4d, R = p-MeC₆H₄) and the two-μ₄-S-containing triple-butterfly iron carbonyl complexes (μ-RS)[μ-Cp(CO)₂FeS] [Fe₂(CO)₆]₃(μ₄-S)₂ (6a, R = Me; 6b, R = Ph; 6c, R =p-MeC₆H₄), respectively. All the new complexes 2a-e, 4a-d, and 6a-c have been characterized by elemental analysis and IR and ¹H NMR spectroscopy, 2a-e have been characterized as well by ¹²⁵Te NMR spectroscopy, and 2a, 4c, and 6c have been characterized by crystal X-ray diffraction techniques.

Full text of DOI:10.1021/om011039v

Organometallics 2002, 21, 1627-1632
1627
Syn th esis a n d Sp ectr oscop ic Ch a r a cter iza tion of
µ4-S-Con ta in in g Dou ble- a n d Tr ip le-Bu tter fly Ir on
Ca r bon yl Com p lexes. Cr ysta l Str u ctu r es of
[(µ-EtTe)F e2(CO)6]2(µ4-S),
(µ-P h S)[µ-Cp (CO)2F eSCdS][F e2(CO)6]2(µ4-S), a n d
(µ-p-MeC6H4S)[µ-Cp (CO)2F eS] [F e2(CO)6]3(µ4-S)2
Li-Cheng Song,*,† Qing-Mei Hu,†,‡ Bao-Wei Sun,† Ming-Yi Tang,† J ing Yang,† and
Yu-J uan Hua†
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 December 5, 2001
We first investigated the nucleophilic reactivities of the complex anions [(µ-RTe)(µ-CO)-
Fe2(CO)6]- (1), {(µ-RS)(µ-SdCS)[Fe2(CO)6]2(µ4-S)}- (3), and {(µ-RS)(µ-S)[Fe2(CO)6]3(µ4-S)2}-
(5) toward the electrophiles SCl2 and Cp(CO)2FeI, respectively. Interestingly, while anions
1 undergo a new type of double nucleophilic substitution reaction with SCl2 to give the series
of one-µ4-S-containing double-butterfly iron carbonyl complexes [(µ-RTe)Fe2(CO)6]2(µ4-S) (2a ,
R ) Et; 2b, R ) Ph; 2c, R ) p-MeC6H4; 2d , R ) o-MeC6H4; 2e, R ) R-C10H7), the single
nucleophilic substitution reactions of anions 3 and 5 with Cp(CO)2FeI afford the one-µ4-S-
containing double-butterfly iron carbonyl complexes (µ-RS)[µ-Cp(CO)2FeSCdS][Fe2(CO)6]2-
(µ4-S) (4a , R ) Me; 4b, R ) Et; 4c, R ) Ph; 4d , R ) p-MeC6H4) and the two-µ4-S-containing
triple-butterfly iron carbonyl complexes (µ-RS)[µ-Cp(CO)2FeS][Fe2(CO)6]3(µ4-S)2 (6a , R ) Me;
6b, R ) Ph; 6c, R ) p-MeC6H4), respectively. All the new complexes 2a -e, 4a -d , and 6a -c
1
have been characterized by elemental analysis and IR and H NMR spectroscopy, 2a -e
have been characterized as well by 125Te NMR spectroscopy, and 2a , 4c, and 6c have been
characterized by crystal X-ray diffraction techniques.
In tr od u ction
interested in studying both µ4-S-forming reactions and
the reactions with µ4-S-containing reactive intermedi-
ates, which has so far led us to obtain a great variety of
double-, triple-, and even multiple-butterfly iron carbo-
nyl complexes.6-10 This article will describe a new type
of µ4-S-forming reaction to give the series of double-
butterfly complexes [(µ-RTe)Fe2(CO)6]2(µ4-S), and the
nucleophilic reactions of the µ4-S-containing anionic
intermediates {(µ-RS)(µ-SdCS)[Fe2(CO)6]2(µ4-S)}- and
{(µ-RS)(µ-S)[Fe2(CO)6]3(µ4-S)2}- to afford the double-
and triple-butterfly complexes (µ-RS)[µ-Cp(CO)2-
FeSCdS][Fe2(CO)6]2(µ4-S) and (µ-RS)[µ-Cp (CO)2FeS]-
[Fe2(CO)6]3(µ4-S)2. In addition, structural characteriza-
tions of these new µ4-S-containing complexes, particu-
larly by X-ray diffraction techniques, are also described.
In 1967, Dahl and co-workers prepared the first µ4-
S-containing double-butterfly iron carbonyl complex [(µ-
MeS)Fe2(CO)6]2(µ4-S) in ∼1% yield.1 Later on, Carleton2
and Glidewell3 also prepared this µ4-S-containing com-
pound by other methods, but the yield is still very low
(13% and ∼1%, respectively). In 1990 de Beer and co-
workers4 prepared another µ4-S-containing double-but-
terfly iron carbonyl complex, [(µ-t-BuS)Fe2(CO)6]2(µ4-S),
in 5% yield; however, to our knowledge, no other µ4-S-
containing butterfly iron carbonyl complexes had been
known before 1988, when we reported a general and
convenient procedure for the synthesis of such double-
butterfly complexes with the general formula [(µ-RS)-
Fe2(CO)6]2(µ4-S) (R) Me, Et, PhCH2, p-MeC6H4,
PhCtC) in high yield (61-91%).5 In view of the novelty
and diversity of structures and reactivities of µ4-S-
containing iron carbonyl complexes, we have been
Resu lts a n d Discu ssion
Syn th eses via Rea ction s of th e An ion s [(µ-RTe)-
(µ-CO)F e2(CO)6]- (1) a n d Ch a r a cter iza tion of [(µ-
* To whom correspondence should be addressed. Fax: +86-22-
23504853. E-mail: lcsong@public.tpt.tj.cn.
† Nankai University.
(6) Song, L.-C.; Yan, C.-G.; Hu, Q.-M.; Wang, R.-J .; Mak, T. C. W.;
Huang, X.-Y. Organometallics 1996, 15, 1535.
(7) Song, L.-C.; Qin, X.-D.; Hu, Q.-M.; Huang, X.-Y. Organometallics
1998, 17, 5437.
‡ State Key Laboratory of Structural Chemistry.
(1) Coleman, J . M.; Wojcicki, A.; Pollick, P. J .; Dahl, L. F. Inorg.
Chem. 1967, 6, 1236.
(2) Carleton, S. C.; Kennedy, F. G.; Knox, S. A. R. J . Chem. Soc.,
Dalton Trans. 1981, 2230.
(3) Glidewell, C.; Hyde, A. R. Inorg. Chim. Acta 1984, 87, L15.
(4) de Beer, J . A.; Haines, R. J . J . Organomet. Chem. 1970, 24, 757.
(5) Song, L.-C.; Kadiata, M.; Wang, J .-T.; Wang, R.-J .; Wang, H.-G.
J . Organomet. Chem. 1988, 340, 239.
(8) Song, L.-C.; Lu, G.-L.; Hu, Q.-M.; Fan, H.-T.; Chen, Y.; Sun, J .
Organometallics 1999, 18, 3258.
(9) 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.
(10) Song, L.-C.; Lu, G.-L.; Hu, Q.-M.; Yang, J .; Sun, J . J . Orga-
nomet. Chem. 2001, 623, 56.
10.1021/om011039v CCC: $22.00 © 2002 American Chemical Society
Publication on Web 03/16/2002

1628 Organometallics, Vol. 21, No. 8, 2002
Song et al.
Sch em e 1
RTe)F e2(CO)6]2(µ4-S) (2a -e). Cr ysta l Str u ctu r e of
2a (R ) E t ). We found that the [MgBr]+ salts of
anions 1, formed from an insertion reaction of elemental
Te with Grignard reagents RMgBr followed by reac-
tion of the intermediates RTeMgBr with Fe3(CO)12,11
could react with an excess amount of SCl2 from -78
°C to room temperature in THF, through a type of
µ4-S-forming reaction to give the series of µ4-S-contain-
ing double-butterfly iron carbonyl complexes 2a -e
(Scheme 1).
F igu r e 1. ORTEP drawing of 2a with atom-labeling
scheme.
Sch em e 2
It is worth pointing out that both the µ4-S-forming
reaction of 1 with SCl2 and the µ4-S-containing double-
butterfly Fe4Te2(µ4-S) products 2a -e are new, although
the µ4-S-containing analogues with a double-butterfly
core Fe4S2(µ4-S)1-5 and Fe4Se2(µ4-S)6 and the corre-
sponding µ4-S-forming reactions1-6 were previously re-
ported. Complexes 2a -e have been characterized by
1
combustion analysis and IR, H NMR, and 125Te NMR
spectroscopy, as well as by X-ray diffraction techniques.
125Te NMR spectroscopy has been developed as an
important tool for characterizing Te-containing orga-
nometallic compounds.12-14 We found that the 125Te
NMR spectra of 2a -e each displayed a singlet in the
region 168.5-309.5 ppm for their two bridged identical
Te atoms. The 125Te NMR resonance signal of 2a (168.5
ppm) appeared at much higher field than those of 2b-e
(242.3-309.5 ppm), which is obviously due to the fact
that the Et group in 2a is an electron-donating group,
whereas the aromatic R groups in 2b-e are electron-
withdrawing.
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 2a
Te(1)-Fe(2)
Te(2)-Fe(4)
Fe(4)-S
2.546(2)
2.533(2)
2.241(2)
2.240(2)
2.243(2)
70.17(6)
129.32(8)
Te(1)-Fe(1)
Te(2)-Fe(3)
Fe(1)-S
Fe(1)-Fe(2)
Fe(3)-Fe(4)
Fe(3)-S-Fe(1)
Fe(1)-S-Fe(2)
2.563(1)
2.555(1)
2.248(2)
2.572(2)
2.577(2)
129.15(8)
69.93(6)
Fe(2)-S
Fe(3)-S
Fe(4)-S-Fe(3)
Fe(4)-S-Fe(2)
It is noteworthy that the reaction of the [MgBr]+ salts
of anions 1 with SCl2 also afforded the corresponding
single-butterfly complexes (µ-RTe)2Fe2(CO)6. This is not
surprising, since reactions involving anions of type 1
were previously reported to produce the same type of
complexes (µ-RTe)2Fe2(CO)6, possibly generated through
decomposition of anions 1 followed by dimerization of
the intermediate fragment (µ-RTe)Fe(CO)3.15 The
known complexes (µ-RTe)2Fe2(CO)6 (R ) Et,11 Ph,15,16
p-MeC6H4,15 o-MeC6H415) were identified by comparison
Fe(1)-Te(1)-Fe(2) 60.45(4) Fe(3)-Te(2)-Fe(4) 60.86(4)
S-Fe(1)-Te(1)
S-Fe(3)-Te(2)
78.82(6) S-Fe(1)-Fe(2)
78.98(5) S-Fe(3)-Fe(4)
54.88(5)
54.87(5)
Te(2)-Fe(3)-Fe(4) 59.14(4) Te(1)-Fe(1)-Fe(2) 59.45(4)
proposed on the basis of similarity with the reactions
of anions 1 with other electrophiles11 (Scheme 2).
Apparently, this mechanism involves a double nucleo-
philic attack of the negatively charged Fe atom in 1 at
the S atom in SCl2 to eliminate two Cl- anions and a
double coordination of the lone electron pairs on the S
atom to the neighboring Fe atoms with concomitant loss
of two µ-CO ligands.
To unequivocally confirm the double-butterfly struc-
tures of the products obtained from the above new type
of reaction, a single-crystal X-ray diffraction analysis
for [(µ-EtTe)Fe2(CO)6]2(µ4-S) (2a ) was performed. While
Figure 1 shows its structure, Table 1 lists the selected
bond lengths and angles. The X-ray diffraction study
revealed that 2a consists of the two butterfly cores
Fe(1)Fe(2)Te(1)S and Fe(3)Fe(4)Te(2)S joined to a spiro
type of S atom, the dihedral angle between Fe(1)-
Fe(2)-S and Fe(3)-Fe(4)-S is 96.6°, each Fe atom
1
of their IR and H NMR spectra with those of authentic
samples, whereas the new complex (R ) R-C10H7) was
characterized by C/H analysis and IR and 1H NMR
spectroscopy.
The mechanism for the µ4-S-forming reaction to
produce the double-butterfly complexes 2a -e can be
(11) Song, L.-C.; Lu, G.-L.; Hu, Q.-M.; Qin, X.-D.; Sun, C.-X.; Yang,
J .; Sun, J . J . Organomet. Chem. 1998, 571, 55.
(12) Bogan, L. E.; Clark, G. R.; Rauchfuss, T. B. Inorg. Chem. 1986,
25, 4050.
(13) Bochman, R. E.; Whitmire, K. H. Organometallics 1993, 12,
1988.
(14) Song, L.-C.; Shi, Y.-C.; Zhu, W.-F.; Hu, Q.-M.; Huang, X.-Y.;
Du, F.; Mao, X.-A. Organometallics 2000, 19, 156.
(15) Song, L.-C.; Yan, C.-G.; Hu, Q.-M.; Huang, X.-Y. Organometal-
lics 1997, 16, 3769.
(16) Schermer, E. D.; Baddley, W. H. J . Organomet. Chem. 1971,
30, 67.

Double- and Triple-Butterfly Iron Carbonyl Complexes
Organometallics, Vol. 21, No. 8, 2002 1629
Sch em e 3
atom. The dihedral angle between Fe(1)-Fe(2)-S(1)
and Fe(3)-Fe(4)-S(1) is 97.1°, while the S(2) atom is
bonded to C(16) of the phenyl group by an equatorial
type of bond.17 The S(4) atom is bound to C(15) as well
as Fe(5) of the Cp(CO)2Fe group; in addition, all 12
carbonyls attached to the Fe(1)-Fe(5) atoms are ter-
minal. The geometric parameters of 4c are similar to
those of its analogue (µ-MeS)(µ-MeSCdS)[Fe2(CO)6]2(µ4-
S).9 For example, in 4c the bond lengths Fe(1)-Fe(2)
and Fe(3)-Fe(4) are 2.5356(6) and 2.6234(5) Å, whereas
in (µ-MeS)(µ-MeSCdS)[Fe2(CO)6]2(µ4-S) the correspond-
ing lengths are 2.5376(8) and 2.6496(7) Å. In addition,
in 4c the coordinated thiocarbonyl C(15)dS(3) is 1.671-
(3) Å, whereas the corresponding thiocarbonyl in (µ-
MeS)(µ-MeSCdS)[Fe2(CO)6]2(µ4-S) is 1.672(4) Å. Appar-
ently, the coordinated thiocarbonyls in 4c and (µ-MeS)-
(µ-MeSCdS)[Fe2(CO)6]2(µ4-S) are just slightly longer
than the corresponding thiocarbonyl in (µ-PhSe)-
(µ-PhCH2SCdS)Fe2(CO)6 (1.63(1) Å)19 but are much
longer than the uncoordinated CdS double bond in free
CS2 (1.554 Å).20
Syn th eses via Rea ction s of An ion s {(µ-RS)(µ-S)-
[F e2(CO)6]3(µ4-S)2}- (5) a n d Ch a r a cter iza tion of (µ-
RS)[µ-Cp (CO)2F eS][F e2(CO)6]3(µ4-S)2 (6a -c). Cr ys-
t a l St r u ct u r e of 6c (R ) p -MeC6H 4). More inte-
restingly, we have found that the [MgX]+ (X ) Br, I)
salts of the novel two-µ4-S-containing triple-butterfly
anions 5, prepared from the sequential reaction of µ-S2-
Fe2(CO)6 with the Grignard reagents RMgX, Fe3(CO)12
and µ-S2Fe2(CO)6,9 could also undergo nucleophilic
substitution reactions with the electrophile Cp(CO)2FeI
in THF at room temperature to give the triple-butterfly
iron carbonyl complexes 6a -c, as shown in Scheme 4.
Products 6a-c were chatacterized by elemental analy-
sis, spectroscopy, and X-ray crystal diffraction analysis.
For example, the IR spectra of 6a -c displayed three
absorption bands in the range 2086-1988 cm-1 for their
terminal carbonyls, whereas the 1H NMR spectra of
6a -c exhibited a singlet at ca. 5.47 ppm for their Cp
groups. In principle, the R and Cp(CO)2Fe groups in
6a -c should be attached to the bridged S atoms by an
equatorial type of bond, to avoid the sterically strong
repulsions between these groups and the structural
moieties axially bonded to their neighboring bridged S
atoms.6,7 Fortunately, this has been confirmed by crystal
X-ray diffraction analysis of 6c. The molecular structure
of 6c is shown in Figure 3, whereas its selected bond
lengths and angles are given in Table 3.
As shown in Figure 3, 6c contains the three butterfly
cores Fe(2)Fe(3)S(1)S(2), Fe(4)Fe(5)S(2)S(3), and
Fe(6)Fe(7)S(3)S(4) joined together by two µ4-S atoms of
S(2) and S(3). In addition, except for Fe(1) with two
terminal carbonyls, each of the Fe atoms from Fe(2) to
Fe(7) is linked to three terminal carbonyls, and the Cp-
(CO)2Fe and p-MeC6H4 groups are bonded to the bridged
S atoms of S(1) and S(4) by an equatorial type of bond,
respectively. It is worthy of note that in the three but-
terfly cores the geometric parameters of the middle
core are slightly different from those of the two side
cores. For example, the bond length of Fe(2)-Fe(3)
(2.5059(11) Å) or Fe(6)-Fe(7) (2.5094(11) Å) is shorter
carries three terminal carbonyls, and both Te atoms are
attached to Et groups by an equatorial type of bond.17
Thus, this structure is completely similar to those of its
analogues [(µ-MeS)Fe2(CO)6]2(µ4-S)1 and [(µ-EtS)Fe2-
(CO)6]2(µ4-S).5 The similarity can be also seen from the
comparable parameters between 2a and its two above-
mentioned analogues. For instance, in 2a the bond
lengths Fe(1)-Fe(2) and Fe(3)-Fe(4) are 2.572(2) and
2.577(2) Å, whereas in [(µ-EtS)Fe2(CO)6]2(µ4-S) the
corresponding bond lengths are 2.542(2) and 2.538(2)
Å. In addition, in 2a the bond angles Fe(1)-S-Fe(2) and
Fe(3)-S-Fe(4) are 69.93(6) and 70.17(6)°, whereas in
the latter the corresponding angles are 69.04(7) and
68.69(7)°. The minor differences in parameters between
2a and [(µ-EtS)Fe2(CO)6]2(µ4-S) are apparently due to
replacement of the two wing-tip S atoms in the butterfly
core of [(µ-EtS)Fe2(CO)6]2(µ4-S) by two Te atoms.
Syn th eses via Rea ction s of th e An ion s {(µ-RS)-
(µ-SdCS)[F e2(CO)6]2(µ4-S)}- (3) a n d Ch a r a cter iza -
tion of (µ-RS)[µ-Cp (CO)2F eSCdS][F e2(CO)6]2(µ4-S)
(4a -d ). Cr ysta l Str u ctu r e of 4c (R ) P h ). Interest-
ingly, we have further found that the novel µ4-S-
containing anionic intermediates 3, which were pre-
pared as their [MgX]+ (X ) Br, I) salts from a sequential
reaction of µ-S2Fe2(CO)6 with the Grignard reagents
RMgX, Fe3(CO)12, and CS2,9 could undergo nucleophilic
substitution reactions with Cp(CO)2FeI in THF at room
temperature, affording the S-functionalized double-
butterfly iron carbonyl conplexes 4a -d , as shown in
Scheme 3.
Complexes 4a -d were characterized by elemental
analysis, spectroscopy, and X-ray crystal diffraction
analysis. For example, the IR spectra of 4a -d showed
one absorption band in the region 1020-999 cm-1 for
the coordinated CdS double bond,18 whereas the 1H
NMR spectra of 4a -d exhibited a singlet in the range
5.03-5.38 ppm for their Cp groups. To unambiguously
confirm the double-butterfly structures of the products
generated from anions 3, a single-crystal X-ray diffrac-
tion analysis for (µ-PhS)[µ-Cp(CO)2FeSCdS][Fe2(CO)6]2-
(µ4-S) (4c) was undertaken. The molecular structure of
4c is shown in Figure 2, whereas its selected bond
lengths and angles are given in Table 2. The X-ray
diffraction study showed that 4c consists of the two
butterfly subcluster cores Fe(1)Fe(2)S(1)S(2) and
Fe(3)Fe(4)S(1)C(15)S(3) joined to a spiro type of S(1)
(17) Shaver, A.; Fitzpatrick, P. J ; Steliou, K.; Butler, I. S. J . Am.
Chem. Soc. 1979, 101, 1313.
(18) Patin, H.; Mignani, G.; Mahe´, C.; Le Marouille, J .-Y.; Southern,
T. G.; Benoit, A.; Grandjean, D. J . Organomet. Chem. 1980, 197, 315.
(19) Song, L.-C.; Yan, C.-G.; Hu, Q.-M.; Wang, R.-J .; Mak, T. C. W.
Organometallics 1995, 14, 5513.
(20) Butler, I. S.; Fenster, A. E. J . Organomet. Chem. 1974, 66, 161.

1630 Organometallics, Vol. 21, No. 8, 2002
Song et al.
F igu r e 2. ORTEP drawing of 4c with atom-labeling scheme.
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 4c
Exp er im en ta l Section
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)12,22 µ-S2Fe2(CO)6,23 the Grignard reagents RMgX,24 SCl2,25
and Cp(CO)2FeI26 were prepared according to literature pro-
cedures, whereas the others used in this paper 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 170SX FT-IR or Bruker Vector 22
infrared spectrophotometer. 1H NMR spectra were recorded
on a Bruker AC-P 200 NMR spectrometer. 125Te NMR spectra
were recorded on a Varian Unity-Plus 400 NMR spectrometer
with Ph2Te2 as external standard, and the chemical shifts are
referenced to Me2Te (δ 0). C/H analyses were performed on a
Yanaco CHN Corder MT-3 analyzer or a Elementar Vario EL
analyzer. Melting points were determined on a Yanaco MP-
500 apparatus and were uncorrected.
Fe(1)-S(1)
Fe(1)-Fe(2)
Fe(2)-S(2)
Fe(3)-S(3)
Fe(5)-S(4)
C(15)-S(3)
2.2532(7)
2.5356(6)
2.2784(8)
2.3119(8)
2.2631(8)
1.671(3)
Fe(1)-S(2)
Fe(2)-S(1)
Fe(3)-S(1)
Fe(3)-Fe(4)
S(1)-Fe(4)
C(15)-S(4)
2.2748(8)
2.2480(7)
2.2366(7)
2.6234(5)
2.2411(7)
1.683(3)
S(1)-Fe(1)-S(2)
76.57(3) Fe(3)-S(1)-Fe(4)
71.73(2)
Fe(3)-S(1)-Fe(2) 126.97(3) Fe(4)-S(1)-Fe(2) 137.08(3)
Fe(3)-S(1)-Fe(1) 133.41(3) S(1)-Fe(2)-Fe(1)
55.81(2)
56.09(2)
76.60(3)
S(1)-Fe(1)-Fe(2)
S(2)-Fe(1)-Fe(2)
Fe(1)-S(2)-Fe(2)
S(3)-Fe(3)-Fe(4)
55.62(2) S(2)-Fe(2)-Fe(1)
56.23(2) S(1)-Fe(2)-S(2)
67.68(2) Fe(4)-S(1)-Fe(1) 130.85(3)
75.67(2) S(1)-Fe(4)-Fe(3)
54.056(19)
Sch em e 4
Sta n d a r d in Situ P r ep a r a tion of [MgBr ]+ Sa lts of th e
An ion s [(µ-RTe)[(µ-CO)F e2(CO)6]- (1). A 100 mL two-
necked flask equipped with a stir bar, a serum cap, and a
reflux condenser topped with a nitrogen inlet tube was charged
with 0.511 g (4.0 mmol) of tellurium powder, 25 mL of THF,
and 4.0 mmol of RMgBr (R ) Et, Ph, p-MeC6H4, o-MeC6H4,
R-C10H7) in Et2O. The mixture was refluxed for 2 h to give a
slight gray solution of RTeMgBr. When the solution was cooled
to room temperature, 2.0 g (3.96 mmol) of Fe3(CO)12 was added
and the reaction mixture was stirred for ca. 0.5 h to produce
a brown-red solution containing the salt of 1[MgBr] (R ) Et,
than that of Fe(4)-Fe(5) (2.5684(11) Å), and the dihe-
dral angle between Fe(2)-Fe(3)-S(1) and Fe(2)-
Fe(3)-(2) (85.02°) or Fe(6)-Fe(7)-S(3) and Fe(6)-
Fe(7)-S(4) (84.00°) is larger than that between Fe(4)-
Fe(5)-S(2) and Fe(4)-Fe(5)-S(3) (73.53°). In fact, the
basic geometric parameters of 6c are comparable with
those of the butterfly Fe/S cluster complexes, such as
(21) Seyferth, D.; Kiwan, A. M.; Sinn, E. J . Organomet. Chem. 1985,
281, 111.
(22) King, R. B. Organometallic Syntheses; Transition-Metal Com-
pounds, Academic Press: New York, 1965; Vol. 1, p 95.
(23) Seyferth, D.; Henderson, R. S.; Song, L.-C. Organometallics
1982, 1, 125.
(24) Gilman, H.; Zoellner, E. A.; Dickey, J . B. J . Am. Chem. Soc.
1929, 51, 1576.
(25) Brauer, G. Handbook of Preparative Inorganic Chemistry, 2nd
ed.; Academic Press: New York, 1963; Vol. 1, p 371.
(26) King, R. B. Organometallic Syntheses; Transition-Metal Com-
pounds, Academic Press: New York, 1965; Vol. 1, p 175.
21
[(µ-PhS)Fe2(CO)6(µ-S)]2 and (µ-PhCH2S)2[Fe2(CO)6]3-
(µ4-S)2.9

Double- and Triple-Butterfly Iron Carbonyl Complexes
Organometallics, Vol. 21, No. 8, 2002 1631
F igu r e 3. ORTEP drawing of 6c with atom-labeling scheme.
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 6c
forded 0.324 g (21%) of 2c as a dark red solid. Mp: 215 °C
dec. Anal. Calcd for C26H14Fe4O12STe2: C, 30.34; H, 1.37.
Found: C, 30.30; H, 1.24. IR (KBr disk): νCtO 2074 (s), 2045
(s), 2034 (vs), 1989 (vs), 1970 (vs) cm-1. 1H NMR (acetone-d6):
2.30 (s. 6H, 2CH3), 7.30 (q, AA′BB′, J ) 7.8 Hz, 8H, 2C6H4)
ppm. 125Te NMR (CDCl3): 306.3 (s) ppm.
P r ep a r a tion of [(µ-o-MeC6H4Te)F e2(CO)6]2(µ4-S) (2d ).
The same procedure as that for 2a was followed, but 1[MgBr]
(R ) o-MeC6H4) was used instead of 1[MgBr] (R ) Et). From
the first main orange-red band was obtained 0.240 g (17%) of
(µ-o-MeC6H4Te)2Fe2(CO)6.15 The second main brown-red band
afforded 0.318 g (21%) of 2d as a red solid. Mp: 216 °C dec.
Anal. Calcd for C26H14Fe4O12STe2: C, 30.34; H, 1.37. Found:
C, 30.36; H, 1.45. IR (KBr disk): νCtO 2082 (s), 2026 (vs), 2010
(s), 1989 (vs), 1973 (vs), 1958 (vs) cm-1. 1H NMR (acetone-d6):
2.54 (s. 6H, 2CH3), 7.07-7.67 (m, 8H, 2C6H4) ppm. 125Te NMR
(CDCl3): 266.2 (s) ppm.
Fe(1)-S(1)
Fe(2)-S(2)
Fe(7)-S(3)
Fe(3)-S(2)
Fe(4)-S(3)
Fe(4)-Fe(5)
2.3008(18)
2.2827(15)
2.2632(14)
2.2809(15)
2.2492(15)
2.5684(11)
S(1)-Fe(2)
Fe(2)-Fe(3)
Fe(7)-S(4)
Fe(3)-S(1)
S(2)-Fe(4)
Fe(6)-Fe(7)
2.2806(16)
2.5059(11)
2.2769(17)
2.2887(17)
2.2642(15)
2.5094(11)
S(3)-Fe(6)-S(4)
S(4)-Fe(6)-Fe(7)
S(3)-Fe(7)-Fe(6)
Fe(2)-S(1)-Fe(3)
76.55(5) S(3)-Fe(6)-Fe(7)
56.63(4) S(3)-Fe(7)-S(4)
56.44(4) S(4)-Fe(7)-Fe(6)
56.29(4)
76.50(5)
56.39(4)
66.52(5) Fe(2)-S(1)-Fe(1) 125.02(7)
Fe(3)-S(1)-Fe(1) 131.15(7) Fe(5)-S(2)-Fe(4)
69.12(5)
Fe(5)-S(2)-Fe(3) 129.27(6) Fe(4)-S(2)-Fe(3) 129.37(7)
Ph, p-MeC6H4, o-MeC6H4, R-C10H7), which was employed
immediately in the preparations of 2a -e.
P r ep a r a tion of [(µ-EtTe)F e2(CO)6]2(µ4-S) (2a ). To the
above prepared solution of 1[MgBr] (R ) Et), which had been
cooled to -78 °C by a dry ice/acetone bath, was added 0.10
mL (1.5 mmol) of SCl2, and this mixture was stirred for 20
min. After the dry ice/acetone bath was removed, the mixture
was naturally warmed to room temperature and then contin-
ued to be stirred for 4 h. The solvent was removed under
reduced pressure. The residue was subjected to TLC separation
using CH2Cl2/petroleum ether (v/v ) 1:20) as eluent. From the
first main red band was obtained 0.289 g (24%) of (µ-EtTe)2Fe2-
(CO)6.11 The second main brown-red band afforded 0.129 g
(10%) of 2a as a red solid. Mp: 113.5 °C dec. Anal. Calcd for
P r ep a r a tion of [(µ-r-C10H7Te)F e2(CO)6]2(µ4-S) (2e). The
same procedure as that for 2a was followed, but 1[MgBr] (R
) R-C10H7) was used instead of 1[MgBr] (R ) Et). From the
first main red band was obtained 0.240 g (15%) of (µ-R-C10H7-
Te)2Fe2(CO)6 as a red solid. Mp: 145-148 °C. Anal. Calcd for
C
26H14Fe2O6Te2: C, 39.57; H, 1.79. Found: C, 39.29; H, 1.55.
IR (KBr disk): νCtO 2060 (s), 2032 (vs), 1988 (vs), 1963 (vs)
cm-1. 1H NMR (CDCl3): 7.00-8.15 (m, 14H, 2C10H7) ppm. The
second main brown-red band afforded 0.286 g (17%) of 2e as
a dark red solid. Mp: 205 °C dec. Anal. Calcd for C32H14Fe4O12
-
SeTe2: C, 34.90; H, 1.28. Found: C, 34.77; H, 1.50. IR (KBr
disk): νCtO 2082 (s), 2050 (vs), 2018 (vs), 1993 (vs), 1977 (vs)
cm-1 1H NMR (CDCl3): 7.01-8.13 (m, 14H, 2C10H7) ppm.
.
C
16H10Fe4O12STe2: C, 21.24; H, 1.11. Found: C, 20.97; H, 1.00.
125Te NMR (CDCl3): 242.3 (s) ppm.
IR (KBr disk): νCtO 2090 (m), 2046 (s), 2042 (vs), 1981 (vs)
1
cm-1. H NMR (CDCl3): 1.50-1.64 (m, 6H, 2CH3), 2.75-2.85
Sta n d a r d in Situ P r ep a r a tion of [MgX]+ Sa lts of th e
An ion s {(µ-RS)(µ-SdCS)[F e2(CO)6]2(µ4-S)}- (3). 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 20 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 given amount of RMgX (R )
Me, Et, Ph, p-MeC6H4) in Et2O by a syringe until the mixture
turned to emerald green to give a solution of the [MgX]+ salts
of the anions [(µ-RS)(µ-S)Fe2(CO)6]-. To this solution was
added 0.252 g (0.5 mmol) of Fe3(CO)12, and then the mixture
was warmed to room temperature by removing the dry ice/
acetone bath and was stirred at this temperature for 1 h to
give a solution of the [MgX]+ salts of the anions {(µ-RS)-
(µ-CO)[Fe2(CO)6]2(µ4-S)}-. To this solution was added 0.10 mL
(1.8 mmol) of CS2, and the mixture was stirred at room
temperature for 1 h to give a red-brown solution containing
(m, 4H, 2CH2) ppm. 125Te NMR (CDCl3): 168.5 (s) ppm.
P r ep a r a tion of [(µ-P h Te)F e2(CO)6]2(µ4-S) (2b). The same
procedure as that for 2a was followed, but 1[MgBr] (R ) Ph)
was used instead of 1[MgBr] (R ) Et). From the first main
orange-red band was obtained 0.202 g (15%) of (µ-PhTe)2Fe2-
(CO)6.15 The second main orange-red band afforded 0.304 g
(20%) of 2b as a red solid. Mp: 202 °C dec. Anal. Calcd for
C
24H10Fe4O12STe2: C, 28.80; H, 1.01. Found: C, 28.65; H, 1.14.
IR (KBr disk): νCtO 2082 (s), 2044 (vs), 2026 (vs), 1985 (vs),
1966 (vs) cm-1 1H NMR (acetone-d6): 7.10-7.64 (m, 10H,
.
2C6H5) ppm. 125Te NMR (CDCl3): 309.5(s) ppm.
P r ep a r a tion of [(µ-p-MeC6H4Te)F e2(CO)6]2(µ4-S) (2c).
The same procedure as that for 2a was followed, but 1[MgBr]
(R ) p-MeC6H4) was used instead of 1[MgBr] (R ) Et). From
the first main red band was obtained 0.521 g (36%) of (µ-p-
MeC6H4Te)2Fe2(CO)6.15 The second main dark red band af-

1632 Organometallics, Vol. 21, No. 8, 2002
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 2a , 4c, a n d 6c
the salt 3[MgX] (R ) Me, Et, Ph, p-MeC6H4; X ) Br, I), which
was immediately used for preparations of 4a -d .
P r ep a r a tion of (µ-MeS)[µ-Cp (CO)2F eSCdS][F e2(CO)6]2-
(µ4-S) (4a ). To the above prepared solution of 3[MgX] (R )
Me; X ) I) was added 0.152 g (0.5 mmol) of Cp(CO)2FeI. After
the mixture was stirred for 12 h, the solvent was removed
under reduced pressure to give a residue, which was subjected
to TLC separation using CH2Cl2/petroleum ether (2/5 v/v) as
eluent. From the main orange-red band 0.161 g (36%) of 4a
was obtained as an orange-red solid. Mp: 145 °C dec. Anal.
Calcd for C21H8Fe5O14S4: C, 28.28; H, 0.90. Found: C, 27.98;
H, 0.89. IR (KBr disk): νCtO 2077 (s), 2051 (vs), 2027 (vs), 1991
2a
4c
6c
mol formula
C
16H10Fe4O12STe2 C26H10Fe5O14S4 C32H12Fe7O20S4‚
CH2Cl2
mol wt
cryst syst
space group
a/Å
b/Å
c/Å
904.90
953.83
monoclinic
P21/n
15.9464(16)
9.6578(10)
23.912(2)
90
105.178(2)
90
3554.2(6)
4
1320.53
monoclinic
P21/n
9.2669(6)
22.5961(15)
22.5997(14)
90
95.8210(10)
90
4707.9(5)
4
triclinic
P1h (#2)
9.042(3)
10.046(3)
16.228(6)
94.46(3)
105.52(3)
108.87(3)
1322.0(9)
2
R/deg
â/deg
1
(vs); νCdS 1005 (s) cm-1. H NMR (CDCl3): 2.23 (s, 3H, CH3),
γ/deg
V/Å3
5.05 (s, 5H, C5H5) ppm.
Z
P r ep a r a tion of (µ-EtS)[µ-Cp (CO)2F eSCdS][F e2(CO)6]2-
(µ4-S) (4b). The same procedure as that for 4a was followed,
but 3[MgX] (R ) Et; X ) Br) was used instead of 3[MgX] (R )
Me; X ) I). From the main orange-red band 0.169 g (37%) of
4b was obtained as a red solid. Mp: 143 °C dec. Anal. Calcd
for C22H10Fe5O14S4: C, 29.17; H, 1.11. Found: C, 28.99; H, 1.30.
IR (KBr disk): νCtO 2077 (s), 2048 (vs), 2029 (vs), 1987 (vs);
Dc/g cm-3
F(000)
2.273
852
1.783
1888
2.289
293
1.863
2608
2.460
293
abs coeff/mm-1 4.452
temp/K
296
wavelength/Å 0.710 69
0.710 73
ω-2θ
50.06
0.710 73
ω-2θ
scan type
2θmax/deg
no. of observns 4643
no. of variables 316
R
ω-2θ
53.9
50.06
5581
595
0.0453
0.1240
0.897
4940
442
νCdS 1001 (s) cm-1 1H NMR (CDCl3): 1.42 (br s, 3H, CH3),
.
2.55 (br s, 2H, CH2), 5.05 (s, 5H, C5H5) ppm.
0.048
0.059
0.0265
0.0609
1.008
P r ep a r a tion of (µ-P h S)[µ-Cp (CO)2F eSCdS][F e2(CO)6]2-
(µ4-S) (4c). The same procedure as that for 4a was followed,
but 3[MgX] (R ) Ph; X ) Br) was used instead of 3[MgX] (R
) Me; X ) I). From the main orange-red band 0.178 g (37%)
of 4c was obtained as a red solid. Mp: 154 °C dec. Anal. Calcd
for C26H10Fe5O14S4: C, 32.74; H, 1.06. Found: C, 32.56; H, 1.04.
IR (KBr disk): νCtO 2078 (s), 2051 (vs), 2032 (vs), 1988 (vs);
Rw
goodness of fit 1.63
largest diff
1.45 (near
to Te1)
0.369
0.853
peak/e Å-3
IR (KBr disk): νCtO 2060 (s), 2040 (vs), 1998 (vs) cm-1. 1H NMR
(acetone-d6): 5.48 (s, 5H, C5H5), 7.33-7.51 (m, 5H, C6H5) ppm.
P r ep a r a tion of (µ-p-MeC6H4S)[µ-Cp F e(CO)2S][F e2-
(CO)6]3(µ4-S)2 (6c). The same procedure as that for 6a was
followed, except that 5[MgX] (R ) p-MeC6H4; X ) Br) was used
instead of 5[MgX] (R ) Me; X ) I). From the main red band
0.182 g (29%) of 6c was obtained as a black solid. Mp: 160 °C
1
νCdS 1006 (s) cm-1. H NMR (acetone-d6): 5.38 (s, 5H, C5H5),
7.25-7.65 (m, 5H, C6H5) ppm.
P r ep a r a tion of (µ-p-MeC6H4S)[µ-Cp (CO)2F eSCdS][F e2-
(CO)6]2(µ4-S) (4d ). The same procedure as that for 4a was
followed, but 3[MgX] (R ) p-MeC6H4; X ) Br) was used instead
of 3[MgX] (R ) Me; X ) I). From the main orange-red band
0.186 g (38%) of 4d was obtained as a red solid. Mp: 141 °C
dec. Anal. Calcd for
C32H12Fe7O20S4: C, 31.11; H, 0.98.
Found: C, 30.96; H, 1.08. IR (KBr disk): νCtO 2056 (s), 2038
(vs), 1997 (vs) cm-1. 1H NMR (CDCl3): 2.29 (s, 3H, CH3), 5.48
(s, 5H, C5H5), 7.15, 7.19, 7.37, 7.41 (q, AA′BB′, 4H, C6H4) ppm.
X-r a y St r u ct u r e Det er m in a t ion s of 2a , 4c, a n d 6c.
Single crystals of 2a , 4c, and 6c 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
an Enraf-Nonius CAD4 or a Bruker SMART 1000 automated
diffractometer with a graphite monochromator with Mo KR
radiation (λ ) 0.710 69 or 0.710 73 Å). The structures were
solved by direct methods and expanded by Fourier techniques.
The final refinements were accomplished by the full-matrix
least-squares method with anisotropic thermal parameters for
non-hydrogen atoms. Hydrogen atoms were located by using
the geometric method. The calculations were performed using
the TEXSAN crystallographic software package of the Molec-
ular Structure Corp. for 2a and the SHELXTL-97 program for
4c and 6c. Details of the crystal data, data collections, and
structure refinements are summarized in Table 4.
dec. Anal. Calcd for
C27H12Fe5O14S4: C, 33.51; H, 1.25.
Found: C, 33.56; H, 1.15. IR (KBr disk): νCtO 2077 (s), 2053
(vs), 2032 (vs), 1994 (vs); νCdS 999 (s) cm-1. H NMR (CDCl3):
1
2.29 (s, 3H, CH3), 5.03 (s, 5H, C5H5), 7.00-7.45 (m, 4H, C6H4)
ppm.
Sta n d a r d in Situ P r ep a r a tion of [MgX]+ Sa lts of th e
An ion s {[(µ-RS)(µ-S)[F e2(CO)6]3(µ4-S)2}- (5). To the [MgX]+
salts of the intermediate anions {(µ-RS)(µ-CO)[Fe2(CO)6]2(µ4-
S)}- (R ) Me, Ph, p-MeC6H4; X ) Br, I) prepared as described
above in the preparation of [MgX]+ salts of anions 3 was added
0.172 g (0.5 mmol) of µ-S2Fe2(CO)6. The mixture was stirred
for 2 h at room temperature to give a solution containing the
salt 5[MgX] (R ) Me, Ph, p-MeC6H4; X ) Br, I), which was
utilized in the following preparations for 6a -c.
P r ep a r a tion of (µ-MeS)[µ-Cp F e(CO)2S][F e2(CO)6]3(µ4-
S)2 (6a ). To the above prepared solution of 5[MgX] (R ) Me;
X ) I) was added 0.258 g (0.75 mmol) of Cp(CO)2FeI. The new
mixture was stirred overnight. Solvent was removed under
reduced pressure to give a residue, which was subjected to TLC
separation using CH2Cl2/petroleum ether (1/7 v/v) as eluent.
From the main red band 0.123 g (21%) of 6a was obtained as
a black solid. Mp: 162 °C dec. Anal. Calcd for C26H8Fe7O20S4:
C, 26.93; H, 0.70. Found: C, 26.50; H, 0.93. IR (KBr disk):
νCtO 2086 (s), 2041 (vs), 1988 (vs) cm-1. 1H NMR (acetone-d6):
2.32 (s, 3H, CH3), 5.46 (s, 5H, C5H5) ppm.
Ack n ow led gm en t. We are grateful to the National
Natural Science Foundation of China and the State Key
Laboratory of Organometallic Chemistry for financial
support.
P r ep a r a tion of (µ-P h S)[µ-Cp F e(CO)2S][F e2(CO)6]3(µ4-
S)2 (6b). The same procedure as that for 6a was followed, but
5[MgX] (R ) Ph; X ) Br) was used instead of 5[MgX] (R )
Me; X ) I). From the main red band 0.138 g (23%) of 6b was
obtained as a black solid. Mp: 156 °C dec. Anal. Calcd for
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 for 2a , 4c, and 6c. This material is
available free of charge via the Internet at http://pubs. acs.org.
C
31H10Fe7O20S4: C, 30.48; H, 0.83. Found: C, 30.20; H, 1.02.
OM011039V