Synthesis of single and double butterfly iron carbonyl complexes by reactions of [(μ-RSe)(μ-CO)Fe2(CO)6]- anions. Crystal structures of (μ-p-MeC6H4Se)[μ-PhCH2N(H)C=S]Fe 2(CO)6 and [(μ-PhSe)(μ-MeAs)Fe2(CO)6]2

Article abstract of DOI:10.1016/S0022-328X(01)00766-5

The in situ reactions of the [Et₃NH]⁺ and [MgBr]⁺ salts of [(μ-RSe)(μ-CO)Fe₂(CO)₆]^- (1) anions with PhC(Cl)=NPh gave single butterfly complexes (μ-RSe)(μ-PhC=NPh)Fe₂(CO)₆ (2, R=Ph; 3, R=p-MeC₆H₄; 4, R=Et), whereas those of the [Et₃NH]⁺ salts of 1 with R′N=C=S afforded single butterfly complexes (μ-RSe)[μ-R′N(H)C=S]Fe₂(CO)₆ (5, R=Ph, R′=Ph; 6, R=p-MeC₆H₄ R′=Ph; 7, R=p-MeC₆H₄, R′=PhCO; 8, R=p-MeC₆H₄, R′=PhCH₂). Compound 8 could also be prepared by reaction of the [MgBr]⁺ salt of 1 (R=p-MeC₆H₄) with PhCH₂NCS followed by treatment with CF₃CO₂H. More interestingly, while the [Et₃NH]⁺ salt of 1 (R=Ph) reacted with Et₃OBF₄ to give a carbyne ligand-bridged single butterfly complex (μ-PhSe)(μ-EtOC)Fe₂(CO)₆ (9), reaction of the [Et₃NH]⁺ salt of 1 (R=Ph) with MeAsI₂ produced a MeAs-AsMe ligand-bridged double butterfly complex [(μ-PhSe)(μ-MeAs)Fe₂(CO)₆]₂ (10). All the new complexes, 2-10, were characterized by elemental analysis and various spectroscopic methods, for complexes 8 and 10, the structures were also confirmed by X-ray diffraction techniques.

Full text of DOI:10.1016/S0022-328X(01)00766-5

Journal of Organometallic Chemistry 627 (2001) 255–262
www.elsevier.nl/locate/jorganchem
Synthesis of single and double butterfly iron carbonyl complexes
by reactions of [(m-RSe)(m-CO)Fe2(CO)6]− anions. Crystal
structures of (m-p-MeC6H4Se)[m-PhCH2N(H)CꢀS]Fe2(CO)6 and
[(m-PhSe)(m-MeAs)Fe2(CO)6]2
Li-Cheng Song a,*, Guo-Liang Lu a, Qing-Mei Hu a, Hong-Tao Fan a, Jiabi Chen b,
Jie Sun b, Xiao-Ying Huang c
a Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai Uni6ersity,
Tianjin 300071, People’s Republic of China
b Laboratory of Organometallic Chemistry, Chinese Academy of Sciences, Shanghai 200032, People’s Republic of China
c State Key Laboratory of Structural Chemistry, Fuzhou 350002, People’s Republic of China
Received 4 January 2001; received in revised form 27 February 2001; accepted 1 March 2001
Abstract
The in situ reactions of the [Et3NH]+ and [MgBr]+ salts of [(m-RSe)(m-CO)Fe2(CO)6]− (1) anions with PhC(Cl)ꢀNPh gave
single butterfly complexes (m-RSe)(m-PhCꢀNPh)Fe2(CO)6 (2, R=Ph; 3, R=p-MeC6H4; 4, R=Et), whereas those of the
[Et3NH]+ salts of 1 with R%NꢀCꢀS afforded single butterfly complexes (m-RSe)[m-R%N(H)CꢀS]Fe2(CO)6 (5, R=Ph, R%=Ph; 6,
R=p-MeC6H4 R%=Ph; 7, R=p-MeC6H4, R%=PhCO; 8, R=p-MeC6H4, R%=PhCH2). Compound 8 could also be prepared by
reaction of the [MgBr]+ salt of 1 (R=p-MeC6H4) with PhCH2NCS followed by treatment with CF3CO2H. More interestingly,
while the [Et3NH]+ salt of 1 (R=Ph) reacted with Et3OBF4 to give a carbyne ligand-bridged single butterfly complex
(m-PhSe)(m-EtOC)Fe2(CO)6 (9), reaction of the [Et3NH]+ salt of 1 (R=Ph) with MeAsI2 produced a MeAsꢁAsMe ligand-bridged
double butterfly complex [(m-PhSe)(m-MeAs)Fe2(CO)6]2 (10). All the new complexes, 2–10, were characterized by elemental
analysis and various spectroscopic methods, for complexes 8 and 10, the structures were also confirmed by X-ray diffraction
techniques. © 2001 Elsevier Science B.V. All rights reserved.
Keywords: RSe-bridged anions; CO-bridged anions; Electrophiles; In situ reactions; Butterfly iron carbonyl complexes; X-ray structures
1. Introduction
plexes. Herein we report the synthesis and spectroscopic
characterization of some new single and double but-
terfly iron complexes obtained from the studied reac-
tions, as well as the molecular structures of
(m-p-MeC6H4Se)[m-PhCH2N(H)CꢀS]Fe2(CO)6 and [(m-
PhSe)(m-MeAs)Fe2(CO)6]2 determined by X-ray diffrac-
tion techniques.
Reactions of anions of type [(m-RSe)(m-CO)Fe2-
(CO)6]− (1) with electrophiles are of great interest and
have been utilized in the synthesis of various butterfly
iron carbonyl complexes containing one or more (m-
RSe)Fe2(CO)6 structural moieties [1,2]. On the basis of
our recent studies on this type of anions [3–5], we
investigated its reactions with electrophiles PhC(Cl)ꢀ
NPh, R%NꢀCꢀS, Et3OBF4 and MeAsI2, in order to
know the reaction modes systematically and to synthe-
size the corresponding new butterfly iron carbonyl com-
2. Results and discussion
2.1. Reactions of [(v-RSe)(v-CO)Fe2(CO)6]− (1) with
PhC(Cl)ꢀNPh leading to (v-RSe)(v-PhCꢀNPh)Fe2-
(CO)6 (2–4; R=Ph, p-MeC6H4, Et)
* Corresponding author. Tel.: +86-22-23502562; fax: +86-22-
23504853.
E-mail address: lcsong@public.tpt.tj.cn (L.-C. Song).
We found that the [Et3NH]+ salts of anions (1;
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)00766-5

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L.-C. Song et al. / Journal of Organometallic Chemistry 627 (2001) 255–262
Scheme 1.
R=Ph, p-MeC6H4) (prepared from RSeH, Fe3(CO)12
and Et3N [4]) reacted in situ with ca. an equimolar
amount of PhC(Cl)ꢀNPh in THF at −78°C to room
temperature to give iminoacyl-bridged single butterfly
complexes 2 and 3 in 22% yield, whereas the [MgBr]+
salt of anion (1; R=Et) (prepared from an insertion
reaction of Grignard reagent EtMgBr with elemental
selenium followed by treatment of the intermediate
EtSeMgBr with Fe3(CO)12 [3]) reacted with
PhC(Cl)ꢀNPh under similar conditions to afford imi-
noacyl-bridged single butterfly complex 4 in 17% yield
(Scheme 1).
It is noteworthy that the above-mentioned reactions
of 1 with the electrophiles always gave single butterfly
compounds of type (m-RSe)2Fe2(CO)6 in 47–70%
yields. While these compounds, similar to their Te
analogs (m-RTe)2Fe2(CO)6) [6], could be regarded as
derived from decomposition of 1 to give fragments
(m-RSe)Fe(CO)3 followed by their dimerization, prod-
ucts 2–4, similar to their Te and S analogs (m-RE)(m-
PhCꢀNPh)Fe2(CO)6 (E=S and Te) [3,7], could be
regarded as produced through a single SN2 process with
attack of an Fe-centered anion at the imino carbon and
subsequent bridging of the iminoacyl ligand by the
nitrogen lone electron pair with the concomitant loss of
the m-CO ligand (Scheme 1).
present we cannot establish 2 and 3 as the e(R) or a(R)
isomer, due to lack of the comparable 77Se-NMR data
associated with this assignment and particularly lack of
the suitable single crystals for determining their molecu-
lar structures.
2.2. Reactions of [(v-RSe)(v-CO)Fe2(CO)6]− (1) with
R%NCS leading to (v-RSe)[v-R%N(H)CꢀS]Fe2(CO)6
(5–8, R=Ph, p-MeC6H4; R%=Ph, PhCO, PhCH2)
We further found that the [Et3NH]+ salts of anions
(1, R=Ph, p-MeC6H4) reacted in situ with ca. an
equimolar quantity of R%NCS (R%=Ph, PhCO, PhCH2)
in THF at room temperature to afford R%N(H)CꢀS-
bridged single butterfly complexes 5–8 in 21–56%
yields, along with corresponding (m-RSe)2Fe2(CO)6 in
32–59% yields (Scheme 2).
Mechanistically, these R%N(H)CꢀS-bridged com-
plexes, similar to N-methylated derivative of 6 [3],
might be viewed as yielded through two major steps.
First, the nucleophilic Fe atom attacks at the heterocu-
mulene carbon of R%NCS followed by coordination of
the lone electron pair of S atom and concurrent loss of
the m-CO ligand to generate a N-centered anion. Then,
this N-centered anion is protonated inter- or in-
tramolecularly by counterion [Et3NH]+ to give final
products (Scheme 2). It is worthy to note that these
R%N(H)CꢀS-bridged complexes can be also prepared by
using [MgX]+ salts of the anions 1. However, in this
case an extra electrophile is needed to protonate the
Products 2–4 are the first examples of m-RSe-bridged
complexes of this type, and have been characterized by
combustion analysis and spectroscopy. For example,
the IR spectra of 2–4, similar to their m-RTe and m-RS
analogs [3,7] showed one medium absorption band in
the range 1543–1558 cm−1 for the CꢀN double bond
coordinated to one of the two Fe atoms through the
lone electron pair of nitrogen atom. In principle, prod-
ucts 2–4 may have two isomers, one with an equatorial
R (denoted as e(R) hereafter) and the other with an
axial R (denoted as a(R) hereafter) [3,7,8]. In fact, 4 is
1
a mixture of the two isomers, since its H-NMR spec-
trum is unlike that of single isomer (m-EtSe)(m-
Ph2As)Fe2(CO)6 which shows a triplet and a quartet for
its ethyl group [3], but instead showed two multiplets in
the range 1.50–2.97 ppm for its ethyl group. However,
2 and 3 have proved each to be a single isomer, since
their 77Se-NMR spectra exhibited only one singlet at
479.74 and 433.89 ppm, respectively. Unfortunately, at
Scheme 2.

L.-C. Song et al. / Journal of Organometallic Chemistry 627 (2001) 255–262
257
Scheme 3.
1
intermediate N-centered anion. For instance, when the
[MgBr]+ salt of 1 (R=p-MeC6H4) reacted with iso-
thiocyanate PhCH2NCS, followed by treatment of
CF3CO2H, complex 8 could be obtained in 21% yield,
along with (m-p-MeC6H4Se)2Fe2(CO)6 in 31% yield.
Products 5–8 have been characterized by elemental
analysis and spectroscopic methods. For example, the
1H-NMR spectra of 5–8 displayed one broad peak in
the range 7.51–10.15 ppm for their NH groups and the
order of chemical shifts for these NH groups (7\6:
5\8) is consistent with the decreasing order of the
electron-withdrawing effects of substituents R% in 5–8
(PhCO\Ph\PhCH2). In addition, the 1H-NMR spec-
trum of 8 showed an octet pattern around 7.19 ppm,
which can be assigned to its CH2 group. This is because
the two protons in CH2 group are magnetically differ-
ent and can be coupled not only to each other (giving
an AB quartet) but also with the proton of the adjacent
NH group (to give an octet). Finally, it should be noted
that although 5–8 may theoretically have a(R) and e(R)
two isomers, they have proved to exist as only one
isomer, since their 77Se-NMR spectra showed only one
singlet at 430.52–480.84 ppm. Fortunately, we have
successfully determined the crystal molecular structure
of 8 by X-ray crystal diffraction techniques, indicating
it as e(R) isomer (vide infra).
elemental analysis, IR, H-NMR and 13C-NMR spec-
troscopy. Since 9 contains the same carbyne ligand
EtOC as its sulfur analog (m-t-BuS)(m-EtOC)Fe2(CO)6
[9], the spectroscopic data of these two complexes relat-
ing to this ligand are almost the same, for instance, they
all showed a singlet at ca. 380 ppm for the carbyne C in
their 13C-NMR spectra.
In previous papers [10,11] we described an unex-
pected reaction of [(m-RS)(m-CO)Fe2(CO)6]− anions
with electrophile MeAsI2 to give a series of double
Fe2SAs butterfly iron carbonyl complexes. In order to
show the generality for this type of reactions, a reaction
of the [Et3NH]+ salt of 1 (R=Ph) with ca. an equimo-
lar amount of MeAsI2 in THF at room temperature
was carried out. As a result, from this reaction the
expected double Fe2SeAs butterfly complex 10 was
obtained in 5% yield, along with (m-PhSe)2Fe2(CO)6 in
60% yield (Scheme 4).
Product 10 was characterized by elemental analysis,
IR and 1H-NMR spectra. In general, 10 may exist,
similar to its m-RS analogs [10,11], as a mixture of
several stereoisomers, in terms of the axial or equatorial
orientations of the substituents Ph and Me attached to
bridged Se and As atoms. However, according to the
1H-NMR spectrum of 10 (it showed only one signal for
its two methyl groups and one set of signals for its two
phenyl groups), it is believed that 10 would exist as only
one of the four stereoisomers (i)–(iv) (Scheme 5). This
is because that only these isomers each contain two Me
and two Ph groups attached to Se and As atoms by the
same e-type or same a-type of bonds, respectively. In
addition, on steric grounds, 10 exists most likely as one
of the two stereoisomers (i) and (iii), since the other
two, i.e. (ii) and (iv) all involve strong steric repulsions
in each butterfly unit between two axially bonded sub-
stituents, namely, Me and Ph in (iii), and Ph and
butterfly unit (m-MeAs)(m-PhSe)Fe2(CO)6. Fortunately,
we have successfully carried out the X-ray crystal dif-
fraction analysis for 10 (vide infra) to confirm it to be
isomer (iii) in which all the Me and Ph groups are
equatorially bonded to Se and As atoms, respectively.
2.3. Reactions of [(v-RSe)(v-CO)Fe2(CO)6]− (1,
R=Ph) with Et3OBF4 or MeAsI2 leading to
(v-PhSe)(v-EtOC)Fe2(CO)6 (9) and
[(v-PhSe)(v-MeAs)Fe2(CO)6]2 (10)
As previously reported [1–5], the reactions of 1 with
electrophiles can be best rationalized in terms of their
action as Fe-centered anions; however, we have found
that 1 can also be regarded as O-centered anions in the
reaction with electrophile Et3OBF4. For example, when
ca. an equimolar amount of 1 (R=Ph) as its [Et3NH]+
salt was reacted with Et3OBF4 in THF at room temper-
ature for 2 h, the O-alkylation product 9 was obtained
in 61% yield (Scheme 3).
So, anions 1 are similar to their m-RS analogs [9] to
have ambident nature. This nature can be readily un-
derstood upon consideration of the two resonance
forms: Fe-centered anions la and O-centered anions lb
(Scheme 3).
Product 9 is the first example containing a carbyne
ligand of this type, which has been characterized by
Scheme 4.

258
L.-C. Song et al. / Journal of Organometallic Chemistry 627 (2001) 255–262
Table 1
,
Selected bond lengths (A) and angles (°) for 8
Bond lengths
Fe(1)ꢁFe(2)
Fe(2)ꢁSe
Fe(1)ꢁC(7)
SꢁC(7)
2.6207(9)
2.3558(7)
1.958(4)
1.691(4)
1.938(4)
Fe(1)ꢁSe
Fe(2)ꢁS
NꢁC(7)
NꢁC(8)
2.3766(9)
2.317(1)
1.329(5)
1.465(6)
SeꢁC(21)
Bond angles
SꢁFe(2)ꢁSe
Fe(1)ꢁSeꢁFe(2)
Fe(1)ꢁC(7)ꢁN
SeꢁFe(1)ꢁC(6)
SꢁC(7)ꢁN
82.10(3)
67.25(3)
125.7(3)
97.6(2)
SꢁC(7)ꢁFe(1)
SeꢁFe(1)ꢁFe(2)
C(7)ꢁNꢁC(8)
SeꢁFe(2)ꢁC(5)
NꢁC(8)ꢁC(11)
113.7(2)
56.00(2)
125.6(4)
103.8(1)
113.8(4)
120.5(3)
2.4. Crystal structures of 8 and 10
Scheme 5.
To confirm unambiguously the structures of single
and double butterfly complexes 8 and 10, the X-ray
Fig. 1. Molecular structure of 8 showing the atom labeling scheme.
Fig. 2. Molecular structure of 10 showing the atom labeling scheme.

L.-C. Song et al. / Journal of Organometallic Chemistry 627 (2001) 255–262
259
,
lengths of the two FeꢁFe bonds (2.606 A) and the four
crystal diffraction analyses for 8 and 10 were per-
formed. The ORTEP drawings of molecular structures of
8 and 10 are shown in Figs. 1 and 2; Tables 1 and 2 list
their bond lengths and angles, respectively.
As can be seen from Fig. 1, 8 has two ligands
m-p-MeC6H4Se and m-PhCH2N(H)CꢀS, which are
bridged to two Fe atoms of the two Fe(CO)3 units to
form the iron carbonyl complex with a single butterfly
SeFe2CS skeleton. In fact, the structure of 8 is very
similar to that of (m-PhSe)(m-PhCH2SCꢀS)Fe2(CO)6
(denoted as PPF hereafter) [12]. For example, in 8 the
,
FeꢁAs bonds (2.332 A) are also very close to the
,
corresponding those in BMF (2.591 A for FeꢁFe and
,
,
2.339 A for FeꢁAs) [10] and PMF (2.585 A for FeꢁFe
,
and 2.336 A for FeꢁAs) [11], respectively. In addition,
since the angles of As(1)···Se(1)ꢁC(15)=155.1°,
As(2)···Se(2)ꢁC(21)=156.7°,
Se(1)ꢁC(15)=155.1°,
Se(1)···As(1)ꢁAs(2)=81.6°, the two phenyl groups are
bound to selenium by e-bonds and the two arsenic
atoms bound to each other by a-bonds (thus the two
methyl groups are inevitably bound to As by e-bonds).
It follows that complex 10, similar to its two sulfur
analogs BMF and PMF [10,11], belongs to isomer
e(Ph)e(Me)e(Me)e(Ph), namely, isomer (iii) shown in
Scheme 5.
,
bond lengths of Fe(1)ꢁFe(2) (2.6207(9) A), Fe(1)ꢁSe
,
,
(2.3766(9) A), Fe(2)ꢁSe (2.3558(7) A), Fe(2)ꢁS (2.317(1)
,
,
,
A), Fe( l)ꢁC(7) (l.958(4) A) and C(7)ꢁS (l.691(4) A)
involved in the butterfly skeleton are very close to
corresponding those in PPF (2.648(3), 2.380(2),
,
2.368(3), 2.307(5), 1.978(7) and l.63(l) A) [12], respec-
tively. The bond length of thiocarbonyl C(7)ꢀS (l.691(4)
3. Experimental
,
A) in 8 is much longer than a typical CꢀS double bond
,
in CS2 (l.554 A) [13]. This is apparently due to its
All reactions were carried out under an atmosphere
of highly purified nitrogen using standard Schlenk and
vacuum-line techniques. Tetrahydrofuran (THF) and
benzene were distilled under nitrogen from sodium/ben-
zophenone ketyl, Et3N from KOH. Se powder, PhNCS,
PhCH2NCS, CF3CO2H were commercially available
and used without further purification. Fe3(CO)12 [16],
PhSeH [17], p-MeC6H4SeH [17], Grignard reagent Et-
MgBr [18], PhC(Cl)ꢀNPh [19], PhCONCS [20],
Et3OBF4 [21], MeAsI2 [22] were prepared according to
the literature. The products were separated by TLC
(20×25×0.25 cm3, silica gel G) and further purified
by recrystallization from mixed CH2Cl2–hexane sol-
vent. IR spectra were recorded on a Nicolet 170 SX
coordination to Fe(l) and Fe(2). In addition, that the
bond length of Fe(l)ꢁC(7) is much shorter than that of
Fe(2)ꢁS, which means that the thiocarbonyl C(7)ꢀS is
bonded to Fe(l) via a s bond with a carbene character
and to Fe(2) via the donation of an unshared electron
pair from S atom [12,14]. It is worth pointing out that
the angle C(21)ꢁSe···C(7) (l50.0°) reveals that the sub-
stituent p-MeC6H4 is attached to Se atom by an equa-
torial bond, namely, 8 belongs to an e-type isomer.
Fig. 2 shows that the structure of 10 is totally similar
to those of its sulfur analogs [(m-t-BuS)(m-
MeAs)Fe2(CO)6]2 (denoted as BMF hereafter) [10] and
[(m-i-PrS)(m-MeAs)Fe2(CO)6]2 (denoted as PMF here-
after) [11], which consists of two butterfly-shaped struc-
tural units [(m-PhSe)(m-MeAs)Fe2(CO)6]2, dimerized via
an AsꢁAs bond. The bond length of As(1)ꢁAs(2) is
1
FTIR spectrophotometer, and H-NMR spectra on a
Bruker AC-P200 NMR spectrometer. 77Se-NMR spec-
tra were recorded on a Unity plus-400 spectrometer
with Ph2Se2 as an external standard and the chemical
shifts were referenced to Me2Se (l 0 ppm). C/H analy-
ses were performed on a Yanaco CHN Corder MT-3
analyzer. Melting points were determined on a Yanaco
MP-500 apparatus.
,
2.446(1) A, which is almost the same as corresponding
,
,
those in BMF (2.435(1) A) and PMF (2.4346(8) A)
[10,11] and very close to the normal AsꢁAs single bond
,
length (ca. 2.4 A) [15]. In complex 10 the average
Table 2
,
Selected bond lengths (A) and angles (°) for 10
3.1. Preparation of (v-PhSe)(v-PhCꢀNPh)Fe2(CO)6 (2)
Bond lengths
A 100-ml three-necked flask equipped with a mag-
netic stir-bar, a N2 inlet tube and a serum cap was
charged with 1.00 g (2.0 mmol) of Fe3(CO)12, 20 ml of
THF, 0.22 ml (2.1 mmol) of PhSeH and 0.32 ml (2.3
mmol) of Et3N. The mixture was stirred at room tem-
perature (r.t.) for 0.5 h to give a brown–red solution,
which was cooled to −78°C. To this solution was
slowly added 0.431 g (2.0 mmol) of PhC(Cl)ꢀNPh in 10
ml of THF (also cooled to −78°C). The mixture was
stirred for 15 min at −78°C and for 12 h at r.t. The
resulting mixture was filtered and the filtrate was con-
Fe(1)ꢁFe(2)
As(1)ꢁAs(2)
As(1)ꢁFe(2)
As(2)ꢁFe(4)
Fe(2)ꢁSe(1)
2.603(2)
2.446(1)
2.335(1)
2.338(2)
2.392(2)
Fe(3)ꢁFe(4)
As(1)ꢁFe(1)
As(2)ꢁFe(3)
Se(1)ꢁFe(1)
Fe(3)ꢁSe(2)
2.608(2)
2.327(2)
2.329(1)
2.393(1)
2.388(2)
Bond angles
Fe(1)ꢁSe(1)ꢁFe(2)
Fe(1)ꢁAs(1)ꢁFe(2)
As(1)ꢁAs(2)ꢁFe(4)
Se(1)ꢁFe(1)ꢁFe(2)
Se(1)ꢁFe(2)ꢁFe(1)
65.91(5)
67.86(5)
119.55(5)
57.04(4)
57.05(4)
As(2)ꢁAs(1)ꢁFe(1)
As(1)ꢁAs(2)ꢁFe(3)
Se(1)ꢁFe(1)ꢁAs(1)
As(1)ꢁFe(1)ꢁFe(2)
As(1)ꢁFe(2)ꢁFe(1)
119.13(5)
121.94(5)
78.24(5)
56.21(4)
55.92(5)

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L.-C. Song et al. / Journal of Organometallic Chemistry 627 (2001) 255–262
densed under reduced pressure. The residue was sub-
jected to TLC separation using CH2Cl2–petroleum
ether (v/v=1:10) as an eluent. From the first red band
was obtained 0.416 g (70%) of (m-PhSe)2Fe2(CO)6,
which was identified by comparison of its melting point
and 1H-NMR spectrum with those of an authentic
sample [23]. From the second band was obtained 0.267
g (22%) of 2 as a red solid; m.p. 147°C (dec.). Anal.
Found: C, 48.93; H, 2.40; N, 2.44. Calc. for
C25H15Fe2NO6Se: C, 48.72; H, 2.44; N, 2.27%. IR (KBr
disk, cm−1): w(CꢀN) 1543m; terminal CꢂO, 2069s,
(acetone-d6): l l.50–1.61 (m, 3H, CH3), 2.86–2.97 (m,
2H, CH2), 6.65–7.33 (m, 10H, 2C6H5).
3.4. Preparation of (v-PhSe)[v-PhN(H)CꢀS]Fe2(CO)6
(5)
The flask described above was charged with 1.00 g
(2.0 mmol) of Fe3(CO)12, 20 ml of THF, 0.22 ml (2.1
mmol) of PhSeH and 0.32 ml (2.3 mmol) of Et3N. The
mixture was stirred for 0.5 h at r.t. to give a brown–red
solution. To the solution was added 0.24 ml (2.0 mmol)
of PhNCS and the mixture was stirred for 16 h. Solvent
was removed under reduced pressure. The residue was
subjected to TLC separation using CH2Cl2–petroleum
ether (v/v=1:3) as eluent. From the first red band was
obtained 0.187 g (32%) of (m-PhSe)2Fe2(CO)6. From the
second band was obtained 0.505 g (44%) of 5 as a red
solid; m.p. 111°C (dec.). Anal. Found: C, 39.66; H,
1.98; N, 2.35. Calc. for C19H11Fe2NO6SSe: C, 39.85; H,
1.92; N, 2.45%. IR (KBr disk, cm−1): w(NꢁH), 3339m;
terminal CꢂO, 2063s, 2020vs, 2005vs, 1975s, 1952s.
.1H-NMR (CDCl3): l 7.24–7.49 (m, 10H, 2C6H5), 8.85
(broad s, 1H, NH). 77Se-NMR (CDCl3, Me2Se): l
480.84 (s).
1
2020vs, 1991vs, 1975s, 1970s, 1944s. H-NMR (CDCl3):
l 6.57–7.51 (m, 15H, 3C6H5). 77Se-NMR (CDCl3,
Me2Se): l 479.74 (s).
3.2. Preparation of
(v-p-MeC6H4Se)(v-PhCꢀNPh)Fe2(CO)6 (3)
The procedure for preparation of 3 is similar to that
of 2, but using 0.360 g (2.1 mmol) of m-p-MeC6H4SeH
instead of PhSeH. The first red band afforded 0.343 g
(55%) of (m-p-MeC6H4Se)2Fe2(CO)6, which was iden-
1
tified by comparison of its melting point and H-NMR
spectrum with those of an authentic sample [12]. The
second band gave 0.275 g (22%) of 3 as a red solid;
m.p. 138°C (dec.). Anal. Found: C, 49.37; H, 2.72; N,
2.43. Calc. for C26H17Fe2NO6Se: C, 49.55; H, 2.70; N,
2.22%. IR (KBr disk, cm−1): w(CꢀN), 1548m; terminal
CꢂO, 2077s, 2053s, 2025vs, 1990s, 1977s, 1960s. 1H-
NMR (acetone-d6): l 2.28 (s, 3H, CH3), 6.71–7.47 (m,
14H, C6H4, 2C6H5). 77Se-NMR (CDCl3, Me2Se): l
433.89 (s).
3.5. Preparation of
(v-p-MeC6H4Se)[v-PhN(H)CꢀS]Fe2(CO)6 (6)
The procedure for the preparation of 6 is similar to
that of 5, but using 0.306g (2.1 mmol) of m-p-
MeC6H4SeH instead of PhSeH. The first band afforded
0.385 g (59%) of (m-p-MeC6H4Se)2Fe2(CO)6. The sec-
ond band gave 0.477 g (41%) of 6 as a red solid; m.p.
110°C (dec.). Anal. Found: C, 40.84; H, 2.35, N, 2.45.
Calc. for C20H13Fe2NO6SSe: C, 40.95; H, 2.39; N,
2.22%. IR (KBr disk, cm−1): w(NꢁH), 3341m; terminal
3.3. Preparation of (v-EtSe)(v-PhCꢀNPh)Fe2(CO)6 (4)
The flask described above was charged with 0.158 g
(2.0 mmol) of Se powder, and 20 ml of THF. To this
stirred suspension was slowly added 2.0 mmol of Et-
MgBr–Et2O solution. The mixture was further stirred
until Se powder was disappeared. Then, 1.00 g (2.0
mmol) of Fe3(CO)12 was added and the mixture was
stirred for 0.5 h. After cooling this mixture to −78°C,
0.216 g (1.0 mmol) of PhC(Cl)ꢀNPh in 5 ml of THF
(also cooled to −78°C) was added. The resulting mix-
ture was filtered and condensed under reduced pressure.
The residue was subjected to TLC separation using
CH2Cl2–petroleum ether (v/v=1:20) as eluent. From
the first red band was obtained 0.217 g (47%) of
(m-EtSe)2Fe2(CO)6, which was identified by comparison
1
CꢂO, 2060s, 2015vs, 1989vs, 1977vs, 1964s. H-NMR
(CDCl3): l 2.29 (s, 3H, CH3), 7.03–7.34 (m, 9H, C6H4,
C6H5), 8.86 (broad s, 1H, NH).
3.6. Preparation of
(v-p-MeC6H4Se)[v-PhCON(H)CꢀS]Fe2(CO)6 (7)
The procedure for preparation of 7 is similar to that
of 5, but 0.360 g (2.1 mmol) of m-p-MeC6H4SeH and
0.27 ml (2.0 mmol) of PhCONCS were used instead of
PhSeH and PhNCS, respectively. The first red band
afforded 0.196 g (32%) of (m-p-MeC6H4Se)2Fe2(CO)6.
The second band gave 0.253 g (21%) of 7 as a red solid;
m.p. 72–74°C. Anal. Found: C, 40.95; H, 2.04; N, 2.46.
Calc. for C2lHl3Fe2NO7SSe: C, 41.06; H, 2.12; N,
2.28%. IR (KBr disk, cm−1): w(NꢁH) 3418m; terminal
CꢂO, 2066s, 2023vs, 1997s, 1975s; CꢀO, 1716m. 1H-
NMR (CDCl3): l 2.29 (s, 3H, CH3), 7.02, 7.06, 7.32,
7.36 (4s, 4H, C6H4), 7.55–7.89 (m, 5H, C6H5), 10.15
(broad s, 1H, NH). 77Se-NMR (CDCl3, Me2Se): l
430.52 (s).
1
of its melting point and H-NMR spectrum with those
of an authentic sample [24]. From second band was
obtained 0.093 g (17%) of 4 as a red solid; m.p. 170°C
(dec.). Anal. Found: C, 44.45; H, 2.76; N, 2.20. Calc.
for C21H15Fe2NO6Se: C, 44.39; H, 2.64; N, 2.47%. IR
(KBr disk, cm−1): w(CꢀN), 1558m; terminal CꢂO,
2065s, 2015vs, 1991s, 1975s, 1966s, 1948s. 1H-NMR

L.-C. Song et al. / Journal of Organometallic Chemistry 627 (2001) 255–262
261
3.7. Preparation of
3.9. Preparation of [(v-PhSe)(v-MeAs)Fe2(CO)6]2 (10)
(v-p-MeC6H4Se)[v-PhCH2N(H)CꢀS]Fe2(CO)6 (8)
The flask described above was charged with 1.00 g
(2.0 mmol) of Fe3(CO)12, 20 ml of THF, 0.22 ml (2.1
mmol) of PhSeH and 0.32 ml (2.3 mmol) of Et3N. The
mixture was stirred at r.t. for 0.5 h to give a brown–red
solution. To the solution was added 0.757 g (2.2 mmol)
of MeAsI2 and the mixture was stirred at r.t. for 24 h.
Solvent was removed under reduced pressure. The
residue was subjected to TLC separation using
CH2Cl2–petroleum ether (v/v=1:20) as eluent. The
Method (i). The procedure for the preparation of 8 is
similar to that of 5, but 0.360 g (2.1 mmol) of m-p-
MeC6H4SeH and 0.27 ml (2.0 mmol) of PhCH2NCS
were used instead of PhSeH and PhNCS, respectively.
Using CH2Cl2–petroleum ether (v/v=1:5) as eluent,
the first band afforded 0.198 g (32%) of (m-p-
MeC6H4Se)2Fe2(CO)6. The second band gave 0.670 g
(56%) of 8 as a red solid; m.p. 108–l09°C. Anal.
Found: C, 42.01; H, 2.52; N, 2.20. Calc. for
C21H15Fe2NO6SSe: C, 42.02; H, 2.50; N, 2.33%. IR
(KBr disk, cm−1): w(NꢁH) 3353m; terminal CꢂO,
first red band afforded 0.354
g (60%) of (m-
PhSe)2Fe2(CO)6. The second band gave 0.054 g (5%) of
10 as a red solid; m.p. 185°C (dec.). Anal. Found: C,
29.70; H, 2.01. Calc. for C26H16As2Fe4O6Se2: C, 29.68;
H, 1.52%. IR (KBr disk, cm−1): w(terminal CꢂO)
1
2061s, 2016vs, 1995vs, 1979vs, 1964s, 1952s. H-NMR
(CDCl3): l 2.29 (s, 3H, CH3), 4.62 (octet, 2J=14.6,
3J=4.2 Hz, 2H, CH2), 7.00–7.38 (m, 9H, C6H4, C6H5),
7.51 (broad s, 1H, NH). 77Se-NMR (CDCl3, Me2Se): l
476.70 (s).
1
2052s, 2023vs, 1976vs, 1954s. H-NMR (CDCl3): l 2.28
(s, 6H, 2CH3), 7.24–7.48 (m, 10H, 2C6H5).
Method (ii). The flask described above was charged
with 0.158 g (2.0 mmol) of Se powder and 20 ml of
THF. To this stirred suspension was slowly added 2.0
mmol of p-MeC6H4MgBr–Et2O solution. The mixture
was further stirred at r.t. until Se powder was disap-
peared. Then, 1.00 g (2.0 mmol) of Fe3(CO)12 was
added and the mixture was stirred at r.t. for 0.5 h to
give a brown solution. To this solution was added 0.14
ml (1.0 mmol) of PhCH2NCS and the mixture was
stirred at r.t. for 16 h. Then, 0.16 ml (2.1 mmol) of
CF3CO2H was added and the mixture was stirred at r.t.
for 2 h. By using the same workup as that of method
(i), 0.189 g (31%) of (m-p-MeC6H4Se)2Fe2(CO)6 was
obtained from the first band and from the second band
was obtained 0.128 g (21%) of 8.
3.10. Single crystal structure determinations of 8 and
10
Single crystals of 8 and 10 suitable for X-ray diffrac-
tion analyses were grown by slow evaporation of their
CH2Cl2–hexane solutions at about 5°C. The crystal
was mounted on an Enraf-Nonius CAD-4 or a Rigaku
Table 3
Crystal data and structural refinements details for 8 and 10
8
10
Empirical formula
C21H15Fe2NO6Se
C
26H16As2Fe4O12-
Se2
Formula weight
Temperature (K)
Crystal system
Space group
Unit cell dimensions
600.07
296
Triclinic
1051.56
293
Monoclinic
P21/c (no. 14)
3.8. Preparation of (v-PhSe)(v-EtOC)Fe2(CO)6 (9)
(
P1(no. 2)
,
The flask described above was charged with 1.00 g
(2.0 mmol) of Fe3(CO)12, 30 ml of benzene, 0.22 ml (2.1
mmol) of C6H5SeH and 0.32 ml (2.3 mmol) of Et3N.
The mixture was stirred for 40 min at r.t. to give a
bright-red solution. To this solution was added 0.38 g
(2.0 mmol) of Et3OBF4 and the mixture was stirred at
r.t. for additional 6 h. Solvent was removed under
reduced pressure. The residue was subjected to TLC
separation using petroleum ether as eluent. The or-
ange–yellow band afforded 0.600 g (61%) of 9 as a red
oil. Anal. Found: C, 36.48; H, 1.87. Calc. for
C15H10FeO7Se: C, 36.55; H, 2.04%. IR (KBr disk,
cm−1): w(terminal CꢂO) 2065s, 2032s, 1991s, 1975s.
1H-NMR (CDCl3): l 1.66 (t, J=7.2 Hz, 3H, CH3),
4.74 (q, J=7.2 Hz, 2H, CH2), 7.24 (s, 5H, C6H5).
13C-NMR (50 MHz, CDCl3): l 14.4 (s, CH3), 87.2 (s,
OCH2), 128.6 (s, 3C of C6H5), 132.9 (s, 2C of C6H5),
135.7 (s, 1C of C6H5), 210.1 (s, carbonyl C’s), 378.9 (s,
carbyne C).
a (A)
8.0415(8)
12.140(2)
13.858(3)
109.86(2)
100.56(2)
104.70(1)
1176(1)
2
10.402(4)
15.766(7)
21.224(3)
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
V (A )
93.61(2)
3
,
3473(2)
4
2.010
2024
5.678
Z
Dcalc (g cm−3
F(000)
)
1.695
596
2.886
Absorption coefficient
(mm−1
)
,
Wavelength (A)
Scan type
2qmax (°)
Number of observations, n 4000
Number of variables, p
0.71069
ꢀ–2q
54.0
0.71069
ꢀ–2q
50.0
4468
416
0.048
0.060
2.29
0.95 and −1.08
289
R
0.043
0.049
1.26
Rw
Goodness-of-fit on F2
Largest difference peak and 0.41 and −0.52
hole (e A
−3
,
)

262
L.-C. Song et al. / Journal of Organometallic Chemistry 627 (2001) 255–262
wood, R. Corriu, A.H. Cowley, M.F. Lappert, A. Nakamura,
M. Pereyre (Editorial Advisory Board), Research Trends, Poo-
japura, Trivandrum, vol. 3, 1999, p. 1 and references therein.
[2] D. Seyferth, G.B. Womack, C.M. Archer, J.C. Dewan,
Organometallics 8 (1989) 430.
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J. Sun, J. Organomet. Chem. 571 (1998) 55.
[4] L.-C. Song, G.-L. Lu, Q.-M. Hu, J. Sun, Organometallics 18
(1999) 2700.
[5] L.-C. Song, G.-L. Lu, Q.-M. Hu, H.-T. Fan, Y. Chen, J. Sun,
Organometallics 18 (1999) 3258.
[6] L.-C. Song, C.-G. Yan, Q.-M. Hu, X.-Y. Huang, Organometal-
lics 16 (1997) 3769.
[7] D. Seyferth, J.B. Hoke, Organometallics 7 (1988) 524.
[8] A. Shaver, P.J. Fitzpatrick, K. Steliou, I.S. Butler, J. Am. Chem.
Soc. 101 (1979) 1313.
[9] D. Seyferth, C.M. Archer, Organometallics 5 (1986) 2572.
[10] L.-C. Song, Q.-M. Hu, J. Organomet. Chem. 414 (1991) 219.
[11] L.-C. Song, Q.-M. Hu, J.-L. He, R.-J. Wang, H.-G. Wang,
Heteroat. Chem. 3 (1992) 465.
[12] L.-C. Song, C.-G. Yan, Q.-M. Hu, R.-J. Wang, T.C.W. Mak,
Organometallics 14 (1995) 5513.
[13] I.S. Butler, A.E. Fenster, J. Organomet. Chem. 66 (1974) 161.
[14] H. Patin, G. Mignani, C. Mahe´, J.-Y. Le Marouille, T.G.
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(1980) 315.
[15] B.M. Gatehouse, J. Chem. Soc. Chem. Commun. (1969) 948.
[16] R.B. King, Transition-Metal Compounds. In: Organometallic
Syntheses, vol. 1, Academic Press, New York, 1965, p. 95.
[17] D.G. Foster, Organic Syntheses Collections, vol. 3, Wiley, New
York, 1955, p. 771.
[18] H. Gilman, E.A. Zoellner, J.B. Dickey, J. Am. Chem. Soc. 51
(1929) 1576.
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769.
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York, 1960, p. 113.
AFC5R diffractometer with a graphite monochromator
,
with Mo–Ka radiation (u=0.7l069 A). Details of the
crystal data, data collections and structure refinements
are summarized in Table 3. The structures were solved
by direct methods and expanded by Fourier techniques.
The final refinements were accomplished by the full-ma-
trix least-squares method with anisotropic thermal
parameters for non-hydrogen atoms. The calculations
for 8 and 10 were performed using the TEXSAN crystal-
lographic software package of the Molecular Structure
Corporation.
4. Supplementary material
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC nos. 155189 and 155190 for 8 and
10, respectively. Copies of this information may be
obtained free of charge from The Director, CCDC, 12
Union Road, Cambridge, CB2 1EZ, UK (Fax: +44-
1223-336033; e-mail: deposit@ccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk).
.
Acknowledgements
We are grateful to the National Natural Science
Foundation of China, the Laboratory of Organometal-
lic Chemistry and the State Key Laboratory of Struc-
tural Chemistry for financial support of this work.
[23] L.-C. Song, C.-G. Yan, Q.-M. Hu, Acta Chim. Sin. 53 (1995)
402.
References
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[1] L.-C. Song, Trends in Organometallic Chemistry, in: J.L. At-