Reactions of monoanions [(μ-RE)(μ-E)Fe2(CO) 6]- and dianions [(μ-E)2Fe 2(CO)6]2- (E = Se, S) with N-substituted benzimidoyl chlorides, leading to novel butterfly Fe/E cluster complexes

Article abstract of DOI:10.1021/om1002655

We have first studied the reactions of monoanions [(μ-RE)(μ-E)Fe ₂(CO)₆]^- (A, E = Se; B, E = S) with electrophile PhC(Cl)=NPh or dianions [(μ-E)₂Fe₂(CO) ₆]^2- (C, E = Se; D, E = S) with electrophiles PhC(Cl)=NR′ (R′ = Ph, p-MeC₆H₄). While monoanion A was found to react with PhC(Cl)=NPh to give expected complexes (μ-RSe)[μ-SeC(Ph)=NPh]Fe₂(CO)₆ (1, R = Me; 2, R = Et; 3, R = m-MeC₆H₄), monoanion B was found to react with PhC(Cl)=NPh to afford unexpected complexes (μ-RS)[η¹-SC(Ph)= NPh-η¹]Fe₂(CO)₆ (4, R = Me; 5, R = Et). Furthermore, while dianion C reacted with PhC(Cl)=NR′ (R′ = Ph, p-MeC₆H₄) to give expected complexes [μ-SeC(Ph)= NR′]₂Fe₂(CO)₆ (6, R′ = Ph; 7, R′ = p-MeC₆H₄), dianion D was found to react with PhC(Cl)=NR′ (R′ = Ph, p-MeC₆H₄) to afford unexpected complexes [μ-SC(Ph)=NR′][η¹-C(Ph)=NR′- η¹]Fe₂(CO)₆ (8, R′ = Ph; 9, R′ = p-MeC₆H₄). All the new complexes 1-9 were characterized by elemental analysis and spectroscopy, and complexes 1 and 4-8 were further structurally confirmed by X-ray crystallography.

Full text of DOI:10.1021/om1002655

5050 Organometallics 2010, 29, 5050–5056
DOI: 10.1021/om1002655
Reactions of Monoanions [(μ-RE)(μ-E)Fe2(CO)6]- and Dianions
[(μ-E)2Fe2(CO)6]2- (E=Se, S) with N-Substituted Benzimidoyl
Chlorides, Leading to Novel Butterfly Fe/E Cluster Complexes†
Li-Cheng Song,* Shu-Zhen Mei, Cui-Ping Feng, Feng-Hua Gong, Jian-Hua Ge, and
Qing-Mei Hu
Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University,
Tianjin 300071, People’s Republic of China
Received April 4, 2010
We have first studied the reactions of monoanions [(μ-RE)(μ-E)Fe2(CO)6]- (A, E=Se; B, E=S)
with electrophile PhC(Cl)dNPh or dianions [(μ-E)2Fe2(CO)6]2- (C, E=Se; D, E=S) with electro-
philes PhC(Cl)dNR0 (R0=Ph, p-MeC6H4). While monoanion A was found to react with PhC(Cl)d
NPh to give expected complexes (μ-RSe)[μ-SeC(Ph)dNPh]Fe2(CO)6 (1, R=Me; 2, R=Et; 3, R=
m-MeC6H4), monoanion B was found to react with PhC(Cl)dNPh to afford unexpected complexes
(μ-RS)[η1-SC(Ph)dNPh-η1]Fe2(CO)6 (4, R=Me; 5, R=Et). Furthermore, while dianion C reacted
with PhC(Cl)dNR0 (R0 =Ph, p-MeC6H4) to give expected complexes [μ-SeC(Ph)dNR0]2Fe2(CO)6
(6, R0 = Ph; 7, R0 = p-MeC6H4), dianion D was found to react with PhC(Cl)dNR0 (R0 = Ph,
p-MeC6H4) to afford unexpected complexes [μ-SC(Ph)dNR0][η1-C(Ph)dNR0-η1]Fe2(CO)6 (8, R0=
Ph; 9, R0 = p-MeC6H4). All the new complexes 1-9 were characterized by elemental analysis and
spectroscopy, and complexes 1 and 4-8 were further structurally confirmed by X-ray crystallography.
Introduction
of dianions C and D5-7 can be prepared in nearly quantita-
tive yields by reductive cleavage of the E-E bond of cluster
(μ-E2)Fe2(CO)6 with Grignard reagents and Super-Hydride
(Et3BHLi), respectively, in THF at -78 °C (Scheme 1). In
addition, these anions have been also demonstrated to be
versatile reagents for synthesis of a wide variety of novel
butterfly Fe/E cluster complexes.8-24 Recently, we published
two papers that described the unexpected production of the
We are interested in studying butterfly Fe/E (E = Se, S)
cluster complexes because of their unique structures and novel
properties,1 as well as their recent widespread uses as bio-
mimetic models for the active site of [FeFe]-hydrogenases.2
Among such cluster complexes the butterfly monoanions
[(μ-RE)(μ-E)Fe2(CO)6]- (A, E=Se; B, E=S) and dianions
[(μ-E)2Fe2(CO)6]2- (C, E=Se; D, E=S) are of great interest,
since they are easily prepared and possess high nucleophilic
reactivity toward various substrates. It is well known that the
[MgX]þ salts of monoanionsA and B3,4 and the dilithium salts
(7) Seyferth, D.; Henderson, R. S. J. Organomet. Chem. 1981, 204, 333.
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† Part of the Dietmar Seyferth Festschrift.
*To whom correspondence should be addressed. Fax: 0086-22-
23504853. E-mail: lcsong@nankai.edu.cn.
ꢀ
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(1) For reviews, see for example: (a) Marko, L.; Marko-Monostory,
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S.; Tobita, H. Chem. Rev. 1998, 98, 2093. (c) Song, L.-C. Acc. Chem. Res.
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pubs.acs.org/Organometallics
Published on Web 06/22/2010
2010 American Chemical Society

Article
Organometallics, Vol. 29, No. 21, 2010 5051
Scheme 1
Scheme 2
Scheme 3
butterfly Fe/S/P cluster complexes from reactions of the
butterflyFe/S cluster anions B and D with a P-based electro-
phile, Ph2PCl.25,26 Closely related to such studies, we further
carried out a study on reactions of anions A-D with another
type of electrophile, namely, the N-substituted benzimidoyl
chlorides PhC(Cl)dNR0, in order to find new reaction modes
and to prepare the corresponding butterfly cluster complexes.
Interestingly, throughthisstudywefound thatthe Se-centered
anions Aand Creacted with PhC(Cl)dNR0 to give the expected
butterfly Fe/Se cluster complexes, whereas reactions of the
S-centered anions B and D afforded the unexpected novel
butterfly Fe/S cluster complexes. Herein we report the inter-
esting results obtained from this study.
That is, as shown in Scheme 3, the initially intermolecular
nucleophilic attack of the S-centered monoanion B at the leav-
ing group(Cl-)-attached C atom of electrophile PhC(Cl)dNPh
would first afford intermediate M1. Then, the intramolecular
nucleophilic attack of the N atom in M1 at its Fe atom with
displacement of mercaptide from Fe would give the unexpected
complexes 4 and 5. As a matter of fact, the intramolecular or
intermolecular nucleophilic attack at iron followed by loss of
the Fe-bound ligand in similar butterfly Fe/S cluster complexes
has been well documented.29-32
Results and Discussion
Reactions of Monoanions [(μ-RE)(μ-E)Fe2(CO)6]- (A, E=
Se; B, E=S) with PhC(Cl)dNPh. Synthesis and Character-
ization of (μ-RSe)[μ-SeC(Ph)dNPh]Fe2(CO)6 (1, R=Me; 2,
R=Et; 3, R=m-MeC6H4) and (μ-RS)[η1-SC(Ph)dNPh-η1]-
Fe2(CO)6 (4, R=Me; 5, R=Et). We found that monoanion
[(μ-RSe)(μ-Se)Fe2(CO)6]- (A, R = Me, Et, m-MeC6H4)
(generated from (μ-Se2)Fe2(CO)6 and Grignard reagents
RMgX shown in Scheme 1)4 reacted in situ with excess
electrophile PhC(Cl)dNPh in THF from -78 °C to room
temperature (via nucleophilic attack of the Se-centered mono-
anion A at the leaving group (Cl-)-attached carbon atom of
PhC(Cl)dNPh) to give the expected butterfly Fe/Se cluster
complexes 1-3 in 50-77% yields (Scheme 2). However, in
contrast to this, we found that monoanion [(μ-RS)(μ-S)Fe2-
(CO)6]- (B, R=Me, Et) (formed from (μ-S2)Fe2(CO)6 and
Grignard reagents RMgX shown in Scheme 1)3 reacted in situ
with PhC(Cl)dNPh under similar conditions to afford un-
expected butterfly Fe/S cluster complexes 4 and 5 in 51% and
77% yields, respectively (Scheme 3).
Complexes 1-5 are air-stable red solids, which were fully
characterized by elemental analysis and spectroscopy. For
example, the IR spectra of 1-5 showed three strong absorp-
tion bands in the range 2071-1987 cm-1 for their terminal
carbonyls and one medium absorption band at about 1620 or
1610 cm-1 for their uncoordinated and coordinated CdN
1
functionalities. The H NMR spectra of 1 and 4 each dis-
played one singlet at 1.98 and 2.50 ppm for the methyl group
attached to their bridged Se and S atoms, respectively. In
addition, the 77Se NMR spectra of 1-3 exhibited two signals
in the range 40-237 ppm for their two different bridged Se
atoms.33-36
The molecular structures of 1, 4, and 5 were confirmed
by X-ray crystallography. While their ORTEP drawings are
shown in Figures 1-3, their selected bond lengths and angles
At the present stage, we are not clear about the mechanism
for formation of the unexpected complexes 4 and 5. How-
ever, according to the familiar nucleophilic mode of mono-
anion B3,27,28 and the studied results regarding reaction of
monoanion B with Ph2PCl,26 we might suggest a possible
pathway to account for the formation of complexes 4 and 5.
(29) Seyferth, D.; Womack, G. B.; Song, L.-C.; Cowie, M.; Hames,
B. W. Organometallics 1983, 2, 928.
(30) van der Vlugt, J. I.; Rauchfuss, T. B.; Wilson, S. R. Chem.;Eur.
J. 2006, 12, 90.
(31) Hogarth, G.; O’Brien, M.; Tocher, D. A. J. Organomet. Chem.
2003, 672, 29.
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€
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(24) Harb, M. K.; Niksch, T.; Windhager, J.; Gorls, H.; Holze, R.;
Lockett, L. T.; Okumura, N.; Evans, D. H.; Glass, R. S.; Lichtenberger,
D. L.; El-khateeb, M.; Weigand, W. Organometallics 2009, 28, 1039.
(25) Song, L.-C.; Zeng, G.-H.; Lou, S.-X.; Zan, H.-N.; Ming, J.-B.;
Hu, Q.-M. Organometallics 2008, 27, 3714.
(26) Song, L.-C.; Zeng, G.-H.; Hu, Q.-M.; Ge, J.-H. Organometallics
2005, 24, 16.
(27) Seyferth, D.; Kiwan, A. M. J. Organomet. Chem. 1985, 286, 219.
(28) Song, L.-C.; Kadiata, M.; Wang, J.-T.; Wang, R.-J.; Wang,
H.-G. J. Organomet. Chem. 1990, 391, 387.
Schollhammer, P.; Talarmin, J.; Yaouanc, J.-J.; Michaud, F.; Kervarec,
N. J. Organomet. Chem. 2009, 694, 2801.
(33) Wardle, R. W. M.; Mahler, C. H.; Chau, C.-N.; Ibers, J. A. Inorg.
Chem. 1988, 27, 2790.
(34) van Hal, J. W.; Whitmire, K. H. Organometallics 1998, 17, 5197.
(35) Luthra, N. P.; Boccanfuso, A. M.; Dunlap, R. B.; Odom, J. D.
J. Organomet. Chem. 1988, 354, 51.
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Chem. 1989, 377, 25.

5052 Organometallics, Vol. 29, No. 21, 2010
Song et al.
Figure 1. ORTEP view of 1 with 30% probability level ellipsoids.
Figure 3. ORTEP view of 5 with 30% probability level ellipsoids.
˚
Table 1. Selected Bond Lengths (A) and Angles (deg)
for 1, 4, and 5
1
Se(2)-Fe(1)
Se(1)-Fe(1)
Fe(1)-Fe(2)
Se(1)-C(7)
2.3755(14)
2.3817(13)
2.5505(13)
1.979(5)
Se(2)-Fe(2)
Se(1)-Fe(2)
N(1)-C(7)
Se(2)-C(20)
2.3816(11)
2.3665(11)
1.253(8)
1.963(7)
Fe(2)-Se(1)-Fe(1)
Fe(1)-Se(2)-Fe(2)
Se(2)-Fe(1)-Se(1)
Se(2)-Fe(1)-Fe(2)
64.98(3)
64.84(3)
81.47(3)
57.69(3)
Se(1)-Fe(2)-Se(2)
C(7)-N(1)-C(14)
N(1)-C(7)-C(8)
N(1)-C(7)-Se(1)
81.664(4)
120.3(5)
130.4(5)
116.5(4)
4
Fe(1)-Fe(2)
Fe(1)-S(1)
Fe(1)-S(2)
Fe(2)-S(1)
2.6503(7)
2.2461(9)
2.3073(8)
2.2427(8)
N(1)-C(8)
C(8)-C(9)
S(2)-C(8)
N(1)-C(15)
1.302(3)
1.491(3)
1.712(2)
1.449(3)
S(1)-Fe(2)-Fe(1)
S(1)-Fe(1)-S(2)
S(1)-Fe(1)-Fe(2)
Fe(2)-S(1)-Fe(1)
53.87(2)
89.604(4)
53.75(2)
72.37(3)
N(1)-Fe(2)-Fe(1)
C(8)-N(1)-Fe(2)
N(1)-Fe(2)-Fe(1)
C(15)-N(1)-Fe(2)
91.48(6)
126.22(16)
91.48(6)
117.29(15)
Figure 2. ORTEP view of 4 with 30% probability level ellipsoids.
are listed in Table 1. Figure 1 shows that complex 1 con-
tains a butterfly Fe1Fe2Se1Se2 cluster core that is attached
to a methyl group via a C20-Se2 equatorial bond and an
N-phenyl benzimidoyl group via a C7-Se1 axial bond, as
well as six terminal carbonyls via Fe1 and Fe2 atoms. The
5
Fe(1)-Fe(2)
Fe(1)-S(1)
Fe(1)-S(2)
Fe(2)-S(2)
2.6488(12)
2.3102(13)
2.2441(13)
2.2455(12)
N(1)-C(7)
C(8)-C(7)
S(1)-C(7)
N(1)-C(14)
1.299(5)
1.491(5)
1.712(4)
1.456(4)
ꢀ
˚
bond length of C7-N1 is 1.253 A, which is close to normal
(1.28 A) for the CdN double bond.37 Figures 2 and 3 display
ꢀ
˚
S(2)-Fe(1)-S(1)
S(1)-Fe(1)-Fe(2)
S(2)-Fe(2)-Fe(1)
Fe(1)-S(2)-Fe(2)
89.44(4)
88.43(4)
53.82(4)
72.31(4)
C(7)-N(1)-Fe(2)
C(14)-N(1)-Fe(2)
N(1)-Fe(2)-S(2)
N(1)-Fe(2)-Fe(1)
126.7(2)
114.7(2)
86.15(9)
91.44(9)
that complexes 4 and 5 are composed of a butterfly cluster
core (Fe1Fe2S1S2C8N1 for 4 and Fe1Fe2S1S2C7N1 for 5)
connected to a methyl group of 4 and ethyl group of 5
through the equatorial C7-S1 and C20-S2 bonds, respec-
tively. The striking structural feature of 4 and 5 is that they all
have a five-membered ring (Fe1Fe2N1C8S2 for 4 and Fe1-
Fe2N1C7S1 for 5) to serve as one wing of their butterfly
ꢀ
˚
longer than that of C7-N1 (1.253 A) attached to the bridged
Se1 atom in complex 1. This implies that the double bonds of
C8-N1 and C7-N1 in 4 and 5 are involved in coordination
with their iron atoms, but not for the double bond of C7-N1
in complex 1. So, the crystallographic analyses of 4 and 5
have not only confirmed their molecular structures but also
provided evidence for the suggested ring isomerization from
a three-membered ring to a five-membered ring. In addition,
ꢀ
˚
cluster cores. The bond lengths of C8-N1 (1.302 A) and
ꢀ
˚
C7-N1 (1.299 A) in the five-membered rings of 4 and 5 are
(37) Special Publication: Chem. Soc. (1965) No. 18: Sandorfy, C. In
The Chemistry of the Carbon Nitrogen Double Bond; Patai, S., Ed.; Wiley:
New York, 1970; Chapter 1.
ꢀ
˚
ꢀ
˚
the Fe1-Fe2 bond lengths in 1 (2.5505 A), 4 (2.6503 A), and

Article
Organometallics, Vol. 29, No. 21, 2010 5053
Scheme 4
Scheme 5
Figure 4. ORTEP view of 6 with 30% probability level ellipsoids.
involved in reaction of dianion D with Ph2PCl;26 (iii)
although the extrusion of one S atom followed by C coordi-
nation in M3 is unprecedented, the extrusion of one Se atom
or one CO followed by the corresponding coordination was
previously observed in similar butterfly Fe/E cluster
complexes;43,44 and (iv) from the studied reactions bypro-
ducts PhC(S)NHPh (80) and PhC(S)NHC6H4Me-p (90) were
isolated along with products 8 and 9, respectively (see
Experimental Section). Presumably, the two byproducts
were generated from the extruded S and excess PhC(Cl)d
NR0 or some species derived from PhC(Cl)dNR0. Finally, it
should be further noted that the S extrusion from M3 is due
to M3 (with two identical R0NdC(Ph)S structural units)
being much less stable thermodynamically than complex 4
or 5, which have only one R0NdC(Ph)S unit.
ꢀ
˚
5 (2.6488 A) are very close to the corresponding metal-metal
bond lengths in similar Fe/E cluster complexes.38-42
Reactions of Dianions [(μ-E)2Fe2(CO)6]2- (C, E=Se; D,
E=S) with PhC(Cl)dNR0. Synthesis and Characterization of
[μ-SeC(Ph)dNR0]2Fe2(CO)6 (6, R0=Ph; 7, R0=p-MeC6H4)
and [μ-SC(Ph)dNR0][η1-C(Ph)dNR0-η1]Fe2(CO)6 (8, R0=Ph;
9, R0=p-MeC6H4). Similarly, treatment of dianion [(μ-Se)2Fe2-
(CO)6]2- (C) (generated from (μ-Se2)Fe2(CO)6 and Et3BHLi
shown in Scheme 1)7 in situ with excess PhC(Cl)dNR0 (R0 =
Ph, p-MeC6H4) in THF from -78 °C to room temperature
gave the expected butterfly Fe/Se complexes 6and 7in 26% and
55% yields, respectively (Scheme 4); however in contrast to
this, reactions of dianion [(μ-S)2Fe2(CO)6]2- (D) (derived from
(μ-S2)Fe2(CO)6 and Et3BHLi shown in Scheme 1)5 with PhC-
(Cl)dNR0 (R0=Ph, p-MeC6H4) under similar conditions resul-
ted in formation of the unexpected butterfly Fe/S cluster com-
plexes 8 and 9 in 32% and 40% yields, respectively (Scheme 5).
A possible pathway for production of the unexpected com-
plexes 8 and 9 is shown in Scheme 5. First, the nucleophilic
attack of the S-centered dianion D at the leaving group(Cl-)-
attached carbon atom in PhC(Cl)dNR0 would give inter-
mediate M2. Then, the intramolecular nucleophilic attack of
the N atom in M2 at its Fe atom with displacement of
mercaptide from Fe would afford intermediate M3. Finally,
products 8 and 9 could be produced by loss of one S atom
from M3 followed by attachment of the C atom to the Fe
atom. Although this pathway is mainly speculative, it seems
reasonable. This is because (i) the nucleophilic attack of the
S-centered dianion D at various organic halides is known to
give symmetrically disubstituted complexes;6 (ii) the intra-
molecular isomerization from M2 to M3 is similar to that
Similar to 1-5, complexes 6-9 are also air-stable red
solids, which were characterized by elemental analysis and
spectroscopy. The IR spectra of 6 and 7 displayed three
absorption bands in the range 2066-1992 cm-1 for their
terminal carbonyls and one band at 1622 cm-1 for their two
identical uncoordinated CdN double bands, whereas 8 and 9
exhibited three absorption bands in the region 2083-1979
cm-1 for their terminal carbonyls and two absorption bands
at about 1630 and 1595 cm-1 for their uncoordinated and
coordinated CdN double bonds, respectively. In addition,
1
the H NMR spectra of 6-9 displayed the corresponding
signals for their phenyl and tolyl groups, and the 77Se NMR
spectra of 6 and 7 each showed one singlet at about 227 ppm
for their two identical bridged Se atoms.33-36
The molecular structures of 6-8 were unequivocally con-
firmed by X-ray diffraction analysis. While Figures 4-6
show their ORTEP views, Table 2 presents their selected
bond lengths and angles. As can be seen in Figures 4 and 5,
complexes 6 and 7 are similar to complex 1, in having a
butterfly Fe1Fe2Se1Se2 cluster core. While complex 6 con-
tains two N-phenyl benzimidoyl groups connected to its Se1
and Se2 via an equatorial Se1-C13 and an axial Se2-C26
bond, complex 7 includes two N-tolyl benzimidoyl groups
attached to its Se1 and Se2 by equatorial Se1-C28 and
(38) Gloaguen, F.; Lawrence, J. D.; Schmidt, M.; Wilson, S. R.;
Rauchfuss, T. B. J. Am. Chem. Soc. 2001, 123, 12518.
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Z.-Y.; Hu, Q.-M. Organometallics 2007, 26, 4921.
ꢀ
˚
Se2-C14 bonds. The bond lengths of C13-N1 (1.246 A)
(40) Lyon, E. J.; Georgakaki, I. P.; Reibenspies, J. H.; Darensbourg,
M. Y. Angew. Chem., Int. Ed. 1999, 38, 3178.
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2009, 103, 805.
(42) Mathur, P.; Manimaran, B.; Trivedi, R.; Hossain, Md. M.;
(43) Song, L.-C.; Yan, C.-G.; Hu, Q.-M.; Wang, R.-J.; Mak,
T. C. W.; Huang, X.-Y. Organometallics 1996, 15, 1535.
(44) Song, L.-C.; Fang, X.-N.; Li, C.-G.; Yan, J.; Bao, H.-L.; Hu,
Q.-M. Organometallics 2008, 27, 3225.
Arabatti, M. J. Organomet. Chem. 1996, 515, 155.

5054 Organometallics, Vol. 29, No. 21, 2010
Song et al.
ꢀ
ꢀ
˚
ꢀ
˚
˚
and C26-N2 (1.200 A) for 6 and those of C14-N1 (1.247 A)
and C28-N2 (1.246 A) for 7 are close to the bond length of
ꢀ
˚
C7-N1(1.253 A) for 1, since these CdN double bonds are
all uncoordinated in these complexes. The X-ray crystal-
lographic study revealed that complex 8 is different from 1
and 4-7, which comprises a butterfly Fe1Fe2S1C20N2
cluster core bound to the N-phenyl benzimidoyl group via
an S1-C7 equatorial bond. Interestingly, complex 8 has a
three-membered ring and a four-membered ring as its two
wings of the butterfly cluster core, whereas complexes 1, 6,
and 7 have two three-membered rings as their two wings of
the butterfly cluster cores, and complexes 4 and 5 have one
three-membered ring and one five-membered ring as their
two wings of the butterfly cluster cores. The bond length of
Figure 5. ORTEP view of 7 with 30% probability level ellipsoids.
ꢀ
˚
C20-N2 (1.292 A) involved in the four-membered ring of 8 is
very close to those of C8-N1(1.302 A) and C7-N1(1.299 A)
in 4 and 5 since they are all coordinated with their iron atoms.
ꢀ
˚
ꢀ
˚
ꢀ
˚
The bond length of the uncoordinated C7-N1 bond (1.267 A)
in 8 is close to those of uncoordinated double bonds C7-N1 in
1, C26-N2/C13-N1 in 6, and C28-N2/C14-N1 in 7. The
ꢀ
˚
ꢀ
˚
bond lengths of Fe1-Fe2 in 6 (2.5199 A), 7 (2.5260 A), and 8
ꢀ
˚
(2.574 A) are very close to those of 1, 4, and 5 and the other
similar butterfly Fe/E cluster complexes.38-42
Conclusions
We have synthesized the expected and unexpected new
butterfly Fe/E cluster complexes 1-9 through reactions of
anions A-D with the corresponding N-substituted benzi-
midoyl chlorides. According to the familiar nucleophilic
substitution modes of anions A-D and the structural
characterization of products 1-9, as well as the isolation
of byproducts 80 and 90 formed from reactions of dianion D
with PhC(Cl)dNR0, we may conclude that (i) complexes 1-3
are generated directly by nucleophilic substitution of mono-
anion A with PhC(Cl)dNPh; (ii) complexes 4 and 5 are pro-
duced via nucleophilic substitution of monoanion B with
PhC(Cl)dNPh followed by skeletal isomerization of the
initially formed butterfly intermediate M1; (iii) complexes 6
and 7 are yielded through direct nucleophilic substitution of
dianion C with PhC(Cl)dNR0; and (iv) complexes 8 and 9 are
formed via the initially nucleophilic substitution of dianion D
with PhC(Cl)dNR0 to give intermediate M2, the skeletal
isomerization of M2 to give intermediate M3, and finally the
one S extrusion from M3. It follows that the formation of the
unexpected products 4, 5, 8, and 9 involves two new reaction
modes associated with monoanion B and dianion D, namely,
the skeletal isomerization of intermediate M1 or M2 and the
S extrusion from intermediate M3. Further studies on the
detailed pathways for formation of such unexpected products
as well as a search for new reaction modes associated with
anions A-D will be carried out in this laboratory.
Figure 6. ORTEP view of 8 with 30% probability level ellipsoids.
˚
Table 2. Selected Bond Lengths (A) and Angles (deg) for 6-8
6
Se(1)-C(13)
Fe(1)-Se(1)
Fe(1)-Se(2)
Fe(1)-Fe(2)
1.993(6)
Se(1)-Fe(2)
Se(2)-Fe(2)
N(2)-C(26)
N(1)-C(13)
2.3800(12)
2.4057(13)
1.200(8)
2.3919(12)
2.4007(13)
2.5199(16)
1.246(7)
Fe(2)-Se(1)-Fe(1)
63.75(4)
C(13)-Se(1)-Fe(1) 111.39(18)
C(26)-Se(2)-Fe(1) 104.9(2)
C(26)-Se(2)-Fe(2) 111.25(19)
N(1)-C(13)-C(12) 120.3(6)
Fe(1)-Se(2)-Fe(2)
N(1)-C(13)-Se(1)
63.23(4)
124.4(5)
N(2)-C(26)-Se(2)
128.1(2)
7
Se(1)-Fe(1)
Se(2)-Fe(2)
Fe(1)-Fe(2)
N1)-C(11)
2.4080(9)
2.3937(9)
2.5260(10)
1.246(6)
Se(1)-Fe(2)
Se(2)-Fe(1)
N(2)-C(28)
N(1)-C(14)
2.4001(8)
2.4087(8)
1.246(6)
1.247(6)
Fe(2)-Se(1)-Fe(1)
63.38(3)
C(28)-Se(1)-Fe(1) 113.63(16)
C(14)-Se(2)-Fe(1) 110.32 (14) C(14)-Se(2)-Fe(2) 112.90(3)
N(1)-C(14)-C(15) 120.6(5)
N(2)-C(28)-Se(1)
Fe(2)-Se(2)-Fe(1)
N(1)-C(14)-Se(2)
63.47(3)
122.4(4)
Experimental Section
122.5(4)
General Comments. All reactions were carried out under an
atmosphere of prepurified nitrogen by using standard Schlenk and
vacuum-line techniques. THF was distilled from Na/benzophenone
ketyl under nitrogen. (μ-S2)Fe2(CO)6,6 (μ-Se2)Fe2(CO)6,7 PhC-
(Cl)dNPh,45 PhC(Cl)dNC6H4Me-p,46 and RMgX47 (R=Me, Et,
8
Fe(1)-S(1)
Fe(1)-Fe(2)
Fe(2)-N(2)
Fe(2)-S(1)
2.2829(18)
2.574(2)
1.991(4)
N(1)-C(7)
N(1)-C(14)
C(20)-N(2)
N(2)-C(27)
1.267(5)
1.417(5)
1.292(4)
1.457(5)
2.2780(18)
S(1)-Fe(1)-Fe(2)
N(2)-Fe(2)-S(1)
C(7)-S(1)-Fe(1)
S(1)-Fe(2)-Fe(1)
55.55(4)
Fe(2)-S(1)-Fe(1)
N(1)-C(7)-S(1)
N(2)-C(20)-Fe(1)
C(20)-N(2)-Fe(2)
68.72(6)
125.4(3)
109.5(3)
108.1(3)
(45) Vaughan, W. R.; Carlson, R. D. J. Am. Chem. Soc. 1962, 84, 769.
(46) Schwarz, J. S. P. J. Org. Chem. 1972, 37, 2906.
(47) Gilman, H.; Zoeller, E. A.; Dickey, J. B. J. Am. Chem. Soc. 1929,
51, 1576.
80.76(12)
115.07(14)
55.73(5)

Article
Organometallics, Vol. 29, No. 21, 2010 5055
m-MeC6H4) were prepared according to literature procedures.
Et3BHLi (1 M in THF) was 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 G (10-40 μm). IR
spectra were recorded on a Bruker Vector 22 or a Bio-Rad FTS 135
infrared spectrophotometer. 1H NMR and 77Se NMR spectra
were obtained on a Bruker AC-P200, a Bruker Avance 300 NMR,
or a Bruker AV 600 NMR spectrometer. Elemental analyses were
performed on an Elementar Vario EL analyzer. Melting points
were determined on a Yanaco MP-500 apparatus and are uncor-
rected.
Preparation of (μ-MeSe)[μ-SeC(Ph)dNPh]Fe2(CO)6 (1). A
100 mL three-necked flask equipped with a magnetic stir-bar,
a rubber septum, and a nitrogen inlet tube was charged with
(μ-Se2)Fe2(CO)6 (0.437 g, 1.0 mmol) and THF (20 mL). The
resulting red solution was stirred and cooled to -78 °C. To this
solution was added an Et2O solution of MeMgI (1.0 mmol) by
syringe until the mixture turned emerald green. The mixture was
stirred for an additional 30 min at -78 °C, and then PhC-
(Cl)dNPh (0.600, 2.78 mmol) was added. After the mixture was
warmed to room temperature, it was stirred for 12 h. Solvent
was removed under reduced pressure. The residue was subjected
to TLC separation using CH2Cl2/petroleum ether (v/v=1:2) as
eluent. From the main red band, 1 was obtained as a red solid
(0.364 g, 57%), mp 33-35 °C (dec). Anal. Calcd for C20H13Fe2-
NO6Se2: C, 37.95; H, 2.07; N, 2.21. Found: C, 37.92; H, 2.07; N,
2.36. IR (KBr disk): νCtO 2065 (s), 2032 (vs),1990 (vs); νCdN
1622 (m) cm-1. 1H NMR (200 MHz, CDCl3, TMS): 1.98 (s, 3H,
CH3), 6.99-7.76 (m, 10H, 2C6H5) ppm. 77Se NMR (76 MMz,
CDCl3, Me2Se): 40.33, 236.37 ppm.
(v/v=1:3) was used as eluent. 5 was obtained as a red solid (0.425 g,
77%), mp 38-40 °C. Anal. Calcd for C21H15Fe2NO6S2: C, 45.60;
H, 2.72; N, 2.54. Found: C, 45.45; H, 2.70; N, 2.57. IR (KBr disk):
1
νCꢁO 2070 (vs), 2032 (vs), 1994 (vs); νCdN 1613 (m) cm-1. H
NMR (200 MHz, CDCl3, TMS):1.62(t, J=7.2 Hz, 3H, CH3), 2.73
(q, J=7.2 Hz, 2H, CH2), 6.56-7.45 (m, 10H, 2C6H5) ppm.
Preparation of [μ-SeC(Ph)dNPh]2Fe2(CO)6 (6). A red solu-
tion of (μ-Se2)Fe2(CO)6 (0.437 g, 1.0 mmol) in THF (20 mL) was
stirred and cooled to -78 °C. To this solution was added a THF
solution of Et3BHLi (2 mL, 2 mmol) by syringe, resulting in an
immediate color change from red to emerald green. The green
mixture was stirred at -78 °C for 30 min, and then PhC-
(Cl)dNPh (1.080, 5.0 mmol) was added, causing a color change
back to red. The new mixture was allowed to warm to room
temperature and stirred at this temperature for 6 h. After solvent
was removed under reduced pressure, the residue was subjected
to TLC separation using CH2Cl2/petroleum ether (1:2.5 v/v) as
eluent. From the main red band, 6 was obtained as a red solid
(0.210 g, 26%), mp 115-116 °C. Anal. Calcd for C32H20Fe2-
N2O6Se2: C, 48.16; H, 2.53; N, 3.51. Found: C, 48.39; H, 2.50; N,
3.59. IR (KBr disk): νCtO 2065 (s), 2035 (vs), 1992 (vs); νCdN
1622 (m) cm-1. 1H NMR (300 MHz, CDCl3, TMS): 6.96-7.73
(m, 20H, 4C6H5) ppm. 77Se NMR (114 MHz, CDCl3, Me2Se):
226.10 ppm.
Preparation of [μ-SeC(Ph)dNC6H4Me-p]2Fe2(CO)6 (7). The
same procedure was employed as that for 6, but PhC(Cl)d
NC6H4Me-p (1.150 g, 5.0 mmol) was utilized in place of PhC(Cl)d
NPh. From the main red band, 7was obtained as a red solid (0.453 g,
55%), mp 128-130 °C. Anal. Calcd for C34H24Fe2N2O6Se2: C,
49.43; H, 2.93; N, 3.39 Found: C, 49.57; H, 3.09; N, 3.35. IR (KBr
disk): νCtO 2066 (s), 2034 (vs), 1992 (vs); νCdN 1622 (m) cm-1
.
Preparation of (μ-EtSe)[μ-SeC(Ph)dNPh]Fe2(CO)6 (2). The
same procedure was followed as that for 1, but EtMgBr was used
instead of MeMgI, and 2 was obtained as a red solid (0.500 g,
77%), mp 32-34 °C. Anal. Calcd for C21H15Fe2NO6Se2: C,
38.99; H, 2.34; N, 2.16. Found: C, 39.00; H, 2.35; N, 2.25. IR
(KBr disk): νCtO 2064 (s), 2032 (vs), 1990 (vs); νCdN 1623 (m)
cm-1. 1H NMR (200 MHz, CDCl3, TMS): 1.30 (t, J=7.2 Hz,
3H, CH3), 2.48 (q, J=7.2 Hz, 2H, CH2), 6.95-7.72 (m, 10H,
2C6H5) ppm. 77Se NMR (38 MMz, CDCl3, Me2Se): 147.20,
234.70 ppm.
1H NMR (300 MHz, CDCl3, TMS): 2.38 (s, 6H, 2CH3), 6.87-7.71
(m, 18H, 2C6H4, 2C6H5) ppm. 77Se NMR (114 MHz, CDCl3,
Me2Se): 228.00 ppm.
Preparation of [μ-SC(Ph)dNPh][η1-C(Ph)dNPh-η1]Fe2(CO)6 (8).
A red solution of (μ-S2)Fe2(CO)6 (0.344 g, 1.0 mmol) in THF
(20 mL) was stirred and cooled to -78 °C, and then a THF solu-
tion of Et3BHLi (2 mL, 2 mmol) was added. The resulting green
mixture was stirredat-78°C for 30min, andthenPhC(Cl)dNPh
(1.080 g, 5.0 mmol) was added. The new mixture was allowed to
warm to room temperature and stirred for 4 h. After removal of
solvent, the residue was subjected to TLC separation using
CH2Cl2/petroleum ether (1:4 v/v) as eluent. From the main red
band, 8 was obtained as a red solid (0.217 g, 32%), mp 56-57 °C .
Anal. Calcd for C32H20Fe2N2O6S: C, 57.17; H, 3.00; N, 4.17.
Found: C, 57.15; H, 3.04; N, 4.25. IR (KBr disk): νCtO 2070 (s),
2035 (s), 1997 (vs); νCdN 1620 (m), 1590 (m) cm-1. 1H NMR (200
MHz, CDCl3, TMS): 6.04-7.96 (m, 20H, 4C6H5) ppm. From the
main yellow band, the known compound PhC(S)NHPh (80) was
obtained as a yellow solid (0.108 g), mp 98-99 °C (lit. 97 °C).48
Anal. Calcd for C13H11NS: C, 73.20; H, 5.20; N, 6.57. Found: C,
73.05; H, 5.17; N, 6.58. IR (KBr disk): νN-H 3328 (m); νCdS 1209
Preparation of (μ-m-MeC6H4Se)[μ-SeC(Ph)dNPh]Fe2(CO)6
(3). The same procedure was followed as that for 1, but m-MeC6-
H4MgBr was used instead of MeMgI, and 3 was obtained as a
red solid (0.354 g, 50%), mp 50-52 °C. Anal. Calcd for C26H17-
Fe2NO6Se2: C, 44.04; H, 2.42; N, 1.98. Found: C, 43.97; H, 2.45;
N, 2.02. IR (KBr disk): νCtO 2067 (s), 2032 (vs), 1994 (vs); νCdN
1
1623 (m) cm-1. H NMR (200 MHz, CDCl3, TMS): 2.25 (s,
3H, CH3), 7.04-7.80 (m, 14H, 2C6H5, C6H4) ppm. 77Se NMR
(38 MHz, CDCl3, Me2Se): 219.98, 228.63 ppm.
Preparation of (μ-MeS)[η1-SC(Ph)dNPh-η1]Fe2(CO)6 (4).
The same equipped flask described above was charged with
(μ-S2)Fe2(CO)6 (0.344 g, 1.0 mmol) and THF (20 mL). The
resulting red solution was stirred and cooled to -78 °C. To this
solution was added an Et2O solution of MeMgI (1.0 mmol) to
cause an immediate color change from red to emerald green. The
green mixture was stirred for an additional 30 min, and then
PhC(Cl)dNPh (0.431 g, 2.0 mmol) was added. After the mixture
was warmed to room temperature, it was stirred for 4 h. Solvent
was removed under reduced pressure to give a residue, which
was subjected to TLC separation. The main red band was eluted
with acetone/petroleum ether (v/v = 1:4). After removel of
solvent 4 was obtained as a red solid (0.277 g, 51%), mp 78 °C
(dec). Anal. Calcd for C20H13Fe2NO6S2: C, 44.56; H, 2.43; N,
2.60. Found: C, 44.45; H, 2.44; N, 2.59. IR (KBr disk): νCtO
2071 (vs), 2033 (vs), 1987 (vs); νCdN 1613 (m) cm-1. 1H NMR
(200 MHz, CDCl3, TMS): 2.50 (s, 3H, CH3), 6.47-7.89 (m, 10H,
2C6H5) ppm.
1
(s) cm-1. H NMR (200 MHz, CDCl3, TMS): 7.24-7.82 (m,
10H, 2C6H5), 8.98 (s, 1H, NH) ppm.
Preparation of [μ-SC(Ph)dNC6H4Me-p][η1-C(Ph)dNC6H4Me-
p-η1]Fe2(CO)6 (9). The same procedure was employed as that for
8, but PhC(Cl)dNC6H4Me-p (1.147 g, 5.0 mmol) was utilized in
place of PhC(Cl)dNPh and acetone/petroleum ether (1:7 v/v)
was used as eluent. From the main red band, 9 was obtained as a
red solid (0.279 g, 40%), mp 58-60 °C. Anal. Calcd for C34H24-
Fe2N2O6S: C, 58.31; H, 3.45; N, 4.00. Found: C, 58.15; H, 3.68;
N, 3.70. IR (KBr disk): νCtO 2083 (m), 2036 (vs), 1979 (vs); νCdN
1
1640 (m), 1599 (s) cm-1. H NMR (200 MHz, CDCl3, TMS):
2.20, 2.34 (2s, 6H, 2CH3), 6.42-8.06 (m, 18H, 2C6H5, 2C6H4)
ppm. From the main yellow band, the known compound
PhC(S)NHC6H4Me-p (90) was obtained as a yellow solid (0.178 g),
mp 129-130 °C (lit. 131 °C).48
Preparation of (μ-EtS)[η1-SC(Ph)dNPh-η1]Fe2(CO)6 (5).
The same procedure was followed as that for 4, except that
EtMgBr was used in place of MeMgI and CH2Cl2/petroleum ether
(48) Reynaud, P.; Moreau, R. C.; Samama, J. P. Bull. Soc. Chim. Fr.
1965, 12, 3623.

5056 Organometallics, Vol. 29, No. 21, 2010
Song et al.
Table 3. Crystal Data and Structure Refinements for 1, 4, and 5
Table 4. Crystal Data and Structure Refinements for 6-8
1
4
5
6
7
8
mol formula
C
20H13Fe2-
NO6Se2
C20H13Fe2-
NO6S2
539.13
monoclinic
P2(1)/n
14.073(3)
10.611(2)
15.801(3)
90
112.86(3)
90
2174.3(8)
4
1.647
1.563
1088
-16 e h e 16
-12 e k e 11
-18 e l e 18
14 606
C21H15Fe2-
NO6S2
553.16
triclinic
P1
11.816(2)
16.939(3)
24.318(5)
70.94(3)
88.46(3)
87.73(3)
4596.5(16)
8
1.599
1.481
2240
-12e h e 14
-18 e k e20
-28 e l e 28
35 176
mol formula
C
32H20Fe2O6-
N2Se2 CH3OH
C
34H24Fe2O6- C32H20Fe2-
N2Se2 N2O6S
672.26
3
mol wt
cryst syst
space group
632.93
mol wt
cryst syst
space group
830.16
826.17
triclinic
P1
orthorhombic
Pna2(1)
7.826 (3)
18.980(7)
14.842(5)
90
monoclinic
P2(1)/c
11.909(4)
18.229(6)
16.324(5)
90
108.439(5)
90
3361.8(18)
4
1.640
3.077
1648
-14 e h e 13
-20 e k e 21
-19 e l e 14
16 790
triclinic
P1
˚
˚
a/A
a/A
13.5607(19)
14.769(2)
17.946(3)
77.737(2)
74.268(2)
77.965(2)
3336.9(8)
4
8.835(8)
11.022(10)
16.683(15)
102.605(14)
101.422(17)
102.630(15)
1495(2)
2
˚
b/A
˚
b/A
˚
c/A
˚
c/A
R/deg
β/deg
γ/deg
R/deg
β/deg
γ/deg
90
90
3
3
˚
˚
V/A
Z
2204.6(14)
4
1.907
14.661
1232
-9 e h e 9
-23 e k e23
-18 e l e 18
21 299
V/A
Z
Dc/g cm-3
Dc/g cm-3
1.645
3.098
1640
1.494
1.088
684
3
3
abs coeff/mm-1
F(000)
index ranges
abs coeff/mm-1
F(000)
index ranges
-16 e h e 12 -4 e h e 11
-17 e k e 17 -13 e k e13
-21 e l e 21 -20 e l e 20
18 180
11 649
50.06
0.0409
0.0747
0.967
no. of reflns
no. of indep
reflns
2θmax/deg
R
Rw
goodness of fit
largest diff peak
˚
and hole/e A
no. of reflns
no. of indep reflns 5923
2θmax/deg
R
Rw
goodness of fit
largest diff peak
˚
and hole/e A
8646
6090
53.06
0.0479
0.0908
0.992
4298
3841
16 150
50.02
0.0457
0.1007
1.107
145.2
0.0427
0.1043
1.084
50.04
0.0345
0.0824
0.821
50.04
0.0522
0.1276
1.018
1.003/-0.411
0.467/-0.324 0.389/-0.343
-3
0.878/-0.959
0.743/-0.531
1.173/-0.926
-3
solved by direct methods using the SHELXS-97 program51 and
refined by full-matrix least-squares techniques (SHELXL-97)52
on F2. Hydrogen atoms were located using the geometric
method. Details of crystal data, data collections, and structure
refinements are summarized in Tables 3 and 4, respectively.
X-ray Structure Determinations of 1 and 4-8. Single crystals
of 1 and 4-8 suitable for X-ray diffraction analyses were grown
by slow evaporation of the diethyl ether/hexane solutions of 1, 4,
and 5, the CH2Cl2/petroleum ether solutions of 6 and 7, and the
CH2Cl2 solution of 8 at 4 °C, respectively. A single crystal of 1, 4,
or 5 was mounted on a Rigaku MM-007 (rotating anode)
diffractometer equipped with Saturn 70CCD. Data were col-
lected at 113(2) K, using a confocal monochromator with Mo
Acknowledgment. We are grateful to the National
Natural Science Foundation of China (20772059, 20972073)
and the Tianjin Natural Science Foundation (09JCZDJC-
27900) for financial support.
˚
KR radiation (λ=0.71070 A) in the ω-φ scanning mode. Data
collection, reduction, and absorption correction were per-
formed by the CRYSTALCLEAR program.49 A single crystal
of 6, 7, or 8 was mounted on a Bruker SMART 1000 automated
diffractometer. Data were collected at room temperature using
Supporting Information Available: Full tables of crystal data,
atomic coordinates and thermal parameters, and bond lengths
and angles for 1 and 4-8 as CIF files. This material is available
free of charge via the Internet at http://pubs.acs.org.
˚
a graphite monochromator with Mo KR radiation (λ=0.71073 A)
in the ω-φ scanning mode. Absorption correction was per-
formed by the SADABS program.50 All the structures were
(49) CRYSTALCLEAR 1.3.6; Rigaku and Rigaku/MSC: The Woodlands,
TX, 2005.
(50) Sheldrick, G. M. SADABS, A Program for Empirical Absorption
(51) Sheldrick, G. M. SHELXS97, A Program for Crystal Structure
Solution; University of G€ottingen: Germany, 1997.
(52) Sheldrick, G. M. SHELXL97, A Program for Crystal Structure
€
€
Refinement; University of Gottingen: Germany, 1997.
Correction of Area Detector Data; University of Gottingen: Germany, 1996.