Reaction of [Et3NH][(μ-RE)(μ-CO)Fe2(CO)6] (E=S, Se) with azides. Synthesis of (μ-RE)(μ-p-R1C6H4N3H)Fe 2(CO)6 and crystal structure of (μ-ButS)(μ-PhN3H)Fe2(CO)6

Article abstract of DOI:10.1016/S0022-328X(00)00039-5

The reaction of [Et₃NH][(μ-RE)(μ-CO)Fe₂(CO)₆] (E=S, Se) (1) with aryl azides gives bridging triazenido complexes (μ-RE)(μ-p-R¹C₆H₄N₃H)Fe ₂(CO)₆ (2-8) (2, RE=Bu^tS, R¹=H; 3, RE=PhS, R¹=H; 4, RE=Bu^tS, R¹=Cl; 5, RE=Bu^tS, R¹=MeO; 6, RE=PhS, R¹=MeO; 7, RE=PhSe, R¹=H; 8, RE=PhSe, R¹=Cl). These complexes were characterized by elemental analyses and ¹H-NMR and IR spectroscopy. The structure of complex 2, established by single-crystal X-ray diffraction analysis, shows that the triazenido ligand binds to two iron centers in a bridging bidentate fashion.

Full text of DOI:10.1016/S0022-328X(00)00039-5

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 601 (2000) 87–92
Reaction of [Et3NH][(m-RE)(m-CO)Fe2(CO)6] (E=S, Se) with
azides. Synthesis of (m-RE)(m-p-R1C6H4N3H)Fe2(CO)6 and crystal
structure of (m-ButS)(m-PhN3H)Fe2(CO)6
Zhong-Xia Wang a,*, Shao-Bin Miao a, Zhong-Yuan Zhou b, Xiang-Ge Zhou b
a Department of Chemistry, Uni6ersity of Science and Technology of China, Hefei, Anhui 230026, PR China
b Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, PR China
Received 25 October 1999; accepted 7 January 2000
Abstract
The reaction of [Et3NH][(m-RE)(m-CO)Fe2(CO)6] (E=S, Se) (1) with aryl azides gives bridging triazenido complexes (m-RE)(m-
p-R1C6H4N3H)Fe2(CO)6 (2–8) (2, RE=ButS, R1=H; 3, RE=PhS, R1=H; 4, RE=ButS, R1=Cl; 5, RE=ButS, R1=MeO;
6, RE=PhS, R1=MeO; 7, RE=PhSe, R1=H; 8, RE=PhSe, R1=Cl). These complexes were characterized by elemental
1
analyses and H-NMR and IR spectroscopy. The structure of complex 2, established by single-crystal X-ray diffraction analysis,
shows that the triazenido ligand binds to two iron centers in a bridging bidentate fashion. © 2000 Elsevier Science S.A. All rights
reserved.
Keywords: Iron; Selenium; Sulfur; Triazenido ligand; Complex; Structure
we initiated a study on the reaction of [(m-RE)(m-
CO)Fe2(CO)6]− (E=S, Se) with ArN3. The expected
products would be triazenido diiron complexes. Appar-
ently, the coordination modes of triazenido ligand on
diiron are also of considerable interest.
1. Introduction
The anionic complexes [(m-RE)(m-CO)Fe2(CO)6]−
(E=S, Se) have been studied extensively and shown to
be versatile reagents for the synthesis of Fe–E cluster
complexes containing a great variety of organic and
inorganic bridging groups [1–18]. In most cases, the
anions act as iron-centered nucleophiles. For example,
reactions with acid chlorides [2], with allyl chloride [12],
and with Ph2PCl [13] yield neutral products in which
the organic group or Ph2P group has replaced the m-CO
ligand of the anion as a bridging group, while reactions
with CS2, with RNCS, and with (m-S2)Fe2(CO)6 result
in formation of anionic initial products [15,19]. Fur-
thermore, the reactivity of azides toward nucleophiles
such as RLi is well known, forming triazenido com-
pounds [20]. Triazenido ligand readily binds to the
main group and transition metals in monodentate,
bidentate and bridging fashions [21–26]. To further
investigate the reactivity of [(m-RE)(m-CO)Fe2(CO)6]−,
2. Results and discussion
When ArN3 (Ar=Ph, p-ClC6H4, p-MeOC6H4) was
added to a solution of [Et3NH][(m-RE)(m-CO)Fe2(CO)6]
(E=S, Se) at room temperature, a reaction ensued,
with gas evolution and slowly color change from
brown–red to red–orange. After chromatographic
work-up, two products, (m-RE)2Fe2(CO)6 and (m-
RE)(m-ArN3H)Fe2(CO)6, were obtained (see Eq. (1)).
Mechanistically, the formation of complexes 2–8 could
be through the nucleophilic iron atoms of 1 attacking
* Corresponding author. Fax: +86-551-3631760.
E-mail address: zxwand@ustc.edu.cn (Z.-X. Wang)
(1)
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(00)00039-5

88
Z.-X. Wang et al. / Journal of Organometallic Chemistry 601 (2000) 87–92
1
at the terminal nitrogen atom of ArN3, followed by
coordination of the lone electron pair of the nitrogen
attached to aryl group and concomitant loss of the
m-CO ligand to generate a nitrogen-centered anion 9,
which is further protonated by the proton of the coun-
terion Et3NH+.
IR spectra. Their H-NMR spectra exhibited respective
organic group resonance signals, but NH signals have
1
not been observed. The H-NMR spectra of complexes
2, 4 and 5 also indicated that each of them exists only
one conformer, i.e. equatorial But group isomer. The
1H-NMR spectra of 3 and 6–8 showed complicated
multiplets for their phenyl groups attached to E atoms,
which did not provide any useful information for the
identification of their isomers. In addition, the 1H-
NMR spectra of complexes 6 and 8 showed the pres-
ence of cyclohexane in the crystalline solids, being
consistent with their elemental analytical results. The
cyclohexane molecules may come from crystallizing sol-
vent petroleum ether. Their IR spectra showed four to
six terminal carbonyl absorption bands in the range of
2078–1961 cm−1. For each of complexes 3–8 the weak
absorption band of NH group was also observed. It is
noteworthy that the IR spectrum of complex 2 recorded
in the solid state as a KBr disc gave two weak NH
absorption bands in the region of lower frequencies,
3299 and 3256 cm−1, respectively, while the spectrum
recorded as CCl4 solution showed only one NH absorp-
tion band at 3355 cm−1. This is ascribed to the pres-
ence of intermolecular hydrogen bonds in the solid
state.
In order to confirm the coordination modes of
ArN3H ligands and the structures of the complexes, a
single crystal X-ray diffraction study for 2 was under-
taken. The structure is presented in Fig. 1, the unit cell
is in Fig. 2 and selected bond lengths and bond angles
are listed in Table 1. The crystal structure showed that
two enantiomeric molecules exist in an independent
unit and the corresponding bond lengths and angles are
almost equivalent. Fig. 1 showed that complex 2 is a
diiron hexacarbonyl complex with both an 2-methyl-2-
propanethiolate and 1-phenyltriazenido ligand bridging
the two metals. The two metal atoms [Fe(1)Fe(2)] and
the three nitrogen atoms [N(1)N(2)N(3)] lie approxi-
mately in one plane and the angle between this plane
and Fe(1)Fe(2)S(1) plane is 94.3°. The plane of phenyl
substituent is skewed considerably with respect to the
plane of the triazenido-group, and the angle between
the two planes is 50.8°. The thiolate ligand is bound
almost symmetrically across the metals and the FeꢀS
It is worth pointing out that the products of the type
(m-RE)(m-ArN3H)Fe2(CO)6 were isolated even in reac-
tions in which iodomethane was added to the reaction
mixture at the time when it was assumed that the
anionic product 9 would be present. It would appear
that anion 9 reacts rapidly to deprotonate the Et3NH+
counterion, so that only the neutral product (m-RE)(m-
ArN3H)Fe2(CO)6 is present when the MeI is added. In
addition, the reaction of p-NO2C6H4N3 with
[Et3NH][(m-RS)(m-CO)Fe2(CO)6] produced only (m-
RS)2Fe2(CO)6. Treatment of [Et3NH][(m-ButS)(m-
CO)Fe2(CO)6] with Me3SiN3 gave (m-ButS)2Fe2(CO)6
and an instable species.
Complexes (m-RS)2Fe2(CO)6 (R=But, Ph) and (m-
PhSe)2Fe2(CO)6 are known and have been identified by
1
comparison of their melting points, IR and H-NMR
spectra with those of authentic samples [27–29].
Complexes 2–8 are air-stable red solids and have
been characterized by elemental analyses, 1H-NMR and
,
,
bond lengths [2.2553(10) A for Fe(1)ꢀS(1), 2.2565(12) A
for Fe(2)ꢀS(1)] are unexceptional [12]. The Fe(1)ꢀFe(2)
distance of 2.6004(8) A is in normal range for diiron
,
hexacarbonyl complexes, however, shorter than that in
bridging allyl hexacarbonyldiiron complex (m-EtS)(m-
,
CH2CHCH2)Fe2(CO)6 [2.675(1) A] [12]. The FeꢀN dis-
,
tances [2.009(3) A for Fe(1)ꢀN(1) and 1.995(3) for
Fe(2)ꢀN(3), respectively] are close to those in complex
(m-RC6H4CꢁNNH)2Fe2(CO)6 (R=H, Me) (between
1.99 and 2.02 A) [30], but longer than those found in
,
Fig. 1. ORTEP representation of the crystal structure of complex 2.
The thermal ellipsoids are drawn at the 20% probability level.
2
,
complexes (m-h -Et2N2)Fe2(CO)6 (av. 1.88 A) and (m3-

Z.-X. Wang et al. / Journal of Organometallic Chemistry 601 (2000) 87–92
89
Fig. 2. Unit cell of complex 2.
h2-Et2N2)Fe3(CO)9 (av. 1.93 A) [31]. The two NꢀN
3. Experimental
,
bonds are nearly equivalent and the N(1)ꢀN(2)ꢀN(3)
angle is 118.2° indicating pronounced p-electron
delocalization.
In addition, it was noted that the head-to-head ar-
rangement of the molecules makes the N3 ligands of
All reactions were carried out under nitrogen using
standard Schlenk techniques. Tetrahydrofuran (THF)
was distilled from sodium benzophenone ketyl. PhSeH
[32] and Fe3(CO)12 [33] were obtained by published
procedures. PhN3, p-ClC6H4N3 and p-MeOC6H4N3
were prepared by reaction of sodium azide with re-
spective diazonium chloride [34]. The solutions of
,
two molecules very close, 3.002 A between N2 and N3%
(or N3 and N2%), supporting the presence of intermolec-
ular hydrogen bonds (Fig. 3). This is also consistent
with its IR spectrum.
[Et3NH][(m-RS)(m-CO)Fe2(CO)6]
and
[Et3NH][(m-

90
Z.-X. Wang et al. / Journal of Organometallic Chemistry 601 (2000) 87–92
Table 1
added 0.12 g (1.01 mmol) of PhN3 with stirring for 40
min. Subsequently 0.30 ml (1.93 mmol) of iodomethane
was added to the mixture. After stirring overnight, the
solvent was removed at reduced pressure and the
residue extracted with petroleum ether (60–90°C). Af-
ter removal of the solvent, the material remaining was
subjected to filtration chromatography (silica gel).
Petroleum ether eluted a first band which gave, after
recrystallization from petroleum ether (60–90°C), 0.07
g (31%) of (m-ButS)2Fe2(CO)6 [30] as red crystals. Fur-
ther elution with 3:7 (v/v) CH2Cl2–petroleum ether
followed by evaporation of the solvent gave 0.18 g
(37%) of red solid 2, m.p. 109–111°C. Anal. Found: C,
38.94; H, 3.14; N, 8.51. Calc. for C16H15Fe2N3O6S: C,
,
Selected bond distances (A) and angles (°) for complex 2
Bond length
Fe(1)ꢀN(1)
Fe(1)ꢀS(1)
Fe(1)ꢀFe(2)
Fe(2)ꢀN(3)
Fe(2)ꢀS(1)
N(1)ꢀN(2)
N(1)ꢀC(7)
N(2)ꢀN(3)
2.0086(16)
2.2551(6)
2.6000(5)
1.9922(17)
2.2566(7)
1.290(2)
Fe(3)ꢀN(4)
Fe(3)ꢀS(2)
Fe(3)ꢀFe(4)
Fe(4)ꢀN(6)
Fe(4)ꢀS(2)
N(4)ꢀN(5)
N(5)ꢀN(6)
2.0138(17)
2.2599(6)
2.6092(5)
1.9667(19)
2.2464(6)
1.304(2)
1.441(3)
1.280(3)
1.280(3)
Bond angles
N(1)ꢀFe(1)ꢀS(1)
N(1)ꢀFe(1)ꢀFe(2)
S(1)ꢀFe(1)ꢀFe(2)
N(3)ꢀFe(2)ꢀS(1)
N(3)ꢀFe(2)ꢀFe(1)
S(1)ꢀFe(2)ꢀFe(1)
Fe(1)ꢀS(1)ꢀFe(2)
N(2)ꢀN(1)ꢀC(7)
N(2)ꢀN(1)ꢀFe(1)
C(7)ꢀN(1)ꢀFe(1)
N(3)ꢀN(2)ꢀN(1)
N(2)ꢀN(3)ꢀFe(2)
84.20(5)
85.27(5)
54.837(19) S(2)ꢀFe(3)ꢀFe(4)
82.81(5)
83.00(5)
N(4)ꢀFe(3)ꢀS(2)
N(4)ꢀFe(3)ꢀFe(4)
82.95(5)
85.95(5)
54.377(17)
83.13(5)
81.99(5)
N(6)ꢀFe(4)ꢀS(2)
N(6)ꢀFe(4)ꢀFe(3)
1
39.29; H, 3.09; N, 8.59%. H-NMR (CDCl3): l (ppm)
1.45 (s, 9H, But), 6.80–7.30 (m, 5H, Ph). IR (KBr disc):
w (cm−1) 3299 w, 3256 w (NH); 2071 s, 2032 vs, 1996
vs, 1980 vs (FeꢀCO). IR (CCl4): w (cm−1) 3355 w (NH);
2072 vs, 2034 vs, 1997 vs, br (FeꢀCO).
54.783(17) S(2)ꢀFe(4)ꢀFe(3)
70.38(2)
54.862(17)
70.761(18)
Fe(4)ꢀS(2)ꢀFe(3)
109.46(16)
125.36(13)
124.95(13)
117.07(16)
129.16(13)
N(5)ꢀN(4)ꢀC(23) 110.62(16)
N(5)ꢀN(4)ꢀFe(3) 123.81(14)
C(23)ꢀN(4)ꢀFe(3) 124.71(13)
N(6)ꢀN(5)ꢀN(4)
N(5)ꢀN(6)ꢀFe(4) 131.41(13)
The reaction was also carried out according to the
same procedure and scale as above but absence of MeI.
After work-up, complex 2 was obtained.
116.38(17)
PhSe)(m-CO)Fe2(CO)6] were prepared by the methods
described in the literature [8,12]. Infrared spectra were
obtained by using a VECTOR22 spectrometer. 1H-
NMR spectra were recorded on either a Varian
EM360L or a JEOL FX-90Q spectrometer. Elemental
analyses were performed with a 240C analyzer.
3.1.1. Compound 3
The same procedure as for 2 was followed, but PhSH
was used instead of ButSH. After work-up, (m-
PhS)2Fe2(CO)6 (57%) [31] and 3 (36%) were obtained. 3,
red crystals, m.p. 114–116°C. Anal. Found: C, 42.42;
H, 2.34; N, 7.99. Calc. for C18H11Fe2N3O6S: C, 42.47;
1
H, 2.18; N, 8.25%. H-NMR (CDCl3): l (ppm) 6.40–
3.1. Preparation of (v-RS)(v-p-R1C6H4N3H)Fe2(CO)6
(2, R=But, R1=H; 3, R=Ph, R1=H; 4, R=But,
R1=Cl; 5, R=But, R1=MeO; 6, R=Ph,
R1=MeO)
6.75 (m, 2H, Ph), 7.05–7.45 (m, 8H, Ph). IR (KBr
disc): w (cm−1) 3343 w (NH); 2078 s, 2031 vs, 2014 s,
2000 vs, 1991 s, 1980 s (FeꢀCO).
A solution of the triethylammonium salt of [(m-
ButS)(m-CO)Fe2(CO)6]− was generated by reacting 0.50
g (0.99 mmol) of Fe3(CO)12, 0.12 ml (1.06 mmol) of
ButSH and 0.15 ml (1.07 mmol) of Et3N in 20 ml of
THF at room temperature (r.t.). To the solution was
3.1.2. Compound 4
The same procedure as for 2 was followed, but
p-ClC6H4N3 was used instead of PhN3. After similar
work-up, (m-ButS)2Fe2(CO)6 (60%) and complex 4
(34%) were obtained. 4, red crystals, m.p. 126–128°C.
Fig. 3. Intermolecular hydrogen bonds of complex 2.

Z.-X. Wang et al. / Journal of Organometallic Chemistry 601 (2000) 87–92
91
3.2. Preparation of (v-PhSe)(v-p-R1C6H4N3H)Fe2-
(CO)6 (7, R1=H; 8, R1=Cl)
Table 2
Crystal data and refinement for complex 2
To a solution of [Et3NH][(m-PhSe)(m-CO)Fe2(CO)6]
generated from 0.92 g (1.83 mmol) of Fe3(CO)12, 0.20
ml (1.88 mmol) of PhSeH and 0.26 ml (1.82 mmol) of
Et3N in about 30 ml of THF was added 0.22 g (1.85
mmol) of PhN3 and stirred overnight at r.t.
Formula
C16H14Fe2N3O6S
488.06
Monoclinic
P21/c
13.6361(18)
24.092(3)
13.0367(17)
102.015(3)
4189.0(10)
8
0.18×0.16×0.12
0.71073
293(2)
ƒ–ꢀ
55.16
26 920
9617
(Rint=0.0914)
4172
0.749
Molecular weight
Crystal system
Space group
,
a (A)
,
b (A)
,
The solvent was removed at reduced pressure and the
residue extracted with petroleum ether (60–90°C). Af-
ter removal of the solvent, the material remaining was
subjected to filtration chromatography (silica gel). Elu-
tion with petroleum ether (60–90°C) yielded, after re-
crystallization from petroleum ether(60–90°C), 0.39 g
(72%) of red crystalline (m-PhSe)2Fe2(CO)6 [32]. Further
elution with 3:7 (v/v) CH2Cl2–petroleum ether followed
by evaporation of the solvent and recrystallization
from petroleum ether (60–90°C) gave 0.24 g (24%)
of red crystalline 7, m.p. 106–108°C. Anal. Found:
C, 38.87; H, 2.17; N, 7.47. Calc. for C18H11Fe2N3O6Se:
C, 38.89; H, 1.99; N, 7.56%. 1H-NMR (CDCl3):
l (ppm) 6.30–7.70 (m, 10H, Ph). IR (KBr disc): w
(cm−1) 3346 w (NH); 2073 s, 2031 vs, 2012 s, 1984 s
(FeꢀCO).
c (A)
i (°)
3
,
V (A )
Z
Crystal size (mm)
Radiation u (A)
Temperature (K)
Scan type
2qmax (°)
,
Total reflections
Independent reflections
Reflections with I\2|(I)
Goodness-of-fit on F2
Final R indices [I\2|(I)]
a
R1
0.0564
0.1269
0.892 and −0.597
b
wR2
−3
,
Largest differences peak and hole (e A
)
a R1=ꢀꢁꢁFoꢁ−ꢁFcꢁꢁ/ꢀꢁFoꢁ.
1/2
b wR2=[ꢀw(F2o−Fc2)2/ꢀwFo4]
.
3.2.1. Compound 8
The same procedure as for 7 was followed, but
p-ClC6H4N3 was used instead of PhN3. After similar
work-up, (m-PhSe)2Fe2(CO)6 (15%) and 8·0.33C6H12
(22%) were obtained. 8·0.33C6H12, red crystals, m.p.
92–94°C. Anal. Found: C, 38.61; H, 2.67; N, 6.64.
Calc. for C18H10ClFe2N3O6Se·0.33C6H12: C, 38.84; H,
2.28; N, 6.79%. 1H-NMR (CDCl3): l (ppm) 1.42 (s, 4H,
C6H12), 6.25–7.40 (m, 9H, Ph+C6H4). IR (KBr disc):
w (cm−1) 3331 w (NH); 2073 s, 2031 vs, 1999 s, 1989 vs
(FeꢀCO).
The reaction was also carried out according to simi-
lar procedure to above, but p-ClC6H4N3 was added to
the anion 1 (RE=PhSe) at −78°C. After stirring
overnight at r.t. and then work-up, complex 8 was
obtained in 23% yield.
Anal. Found: C, 37.10; H, 2.92; N, 8.11. Calc. for
1
C16H14ClFe2N3O6S: C, 36.71; H, 2.70; N, 8.03%. H-
NMR (CCl4): l (ppm) 1.46 (s, 9H, But), 7.05 (q, J=8.0
Hz, 4H, C6H4). IR (KBr disc): w (cm−1) 3333 w (NH);
2071 s, 2033 vs, 1994 vs, 1979 s, 1961 s (FeꢀCO).
3.1.3. Compound 5
The same procedure as for 2 was followed, but
p-MeOC6H4N3 was used instead of PhN3. After similar
work-up, (m-ButS)2Fe2(CO)6 (53%) and complex 5
(40%) were obtained. 5, red crystals, m.p. 132–134°C.
Anal. Found: C, 39.46; H, 3.66; N, 8.12. Calc. for
1
C17H17ClFe2N3O7S: C, 39.34; H, 3.30; N, 8.10%. H-
NMR (CCl4): l (ppm) 1.50 (s, 9H, But), 3.75 (s, 3H,
Me), 6.20–7.10 (m, 4H, C6H4). IR (KBr disc): w (cm−1
)
3.3. Crystal data and structure determination of
complex 2
3316 w (NH); 2068 s, 2029 vs, 2002 vs, 1984 s (FeꢀCO).
3.1.4. Compound 6
Red–black crystals of complex 2 were grown from
petroleum ether–CH2Cl2 solution at r.t. Data were
collected on a Siemens P4 four-circle diffractometer
using graphite-monochromated Mo–Ka radiation. Ab-
sorption correction was applied using SADABS. Struc-
ture was solved by direct method and refined by
full-matrix least-squares on F2 with anisotropic thermal
parameters for non-hydrogen atoms on a PC using
SHELXTL software package. A summary of crystal data
and refinement parameters is given in Table 2.
The same procedure as for 3 was followed, but
p-MeOC6H4N3 was used instead of PhN3. After similar
work-up, (m-PhS)2Fe2(CO)6 (33%) and 6·0.2C6H12
(31%) were isolated. 6·0.2C6H12, red crystals, m.p. 110–
112°C. Anal. Found: C, 43.81; H, 2.83; N, 7.53. Calc.
for C19H13Fe2N3O7S·0.2C6H12: C, 43.64; H, 2.79; N,
7.56%. 1H-NMR (CDCl3): l (ppm) 1.40 (s, 2.4H,
C6H12), 3.70 (s, 3H, Me), 6.20–7.40 (m, 9H, Ph+
C6H4). IR (KBr disc): w (cm−1) 3322 w (NH); 2076 vs,
2034 vs, 1996 s, 1984 s, br (FeꢀCO).

92
Z.-X. Wang et al. / Journal of Organometallic Chemistry 601 (2000) 87–92
[12] D. Seyferth, G.B. Womack, C.M. Archer, J.C. Dewan,
4. Supplementary material
Organometallics 8 (1989) 430.
[13] D. Seyferth, K.S. Brewer, G.B. Womack, C.M. Archer, J.
Organomet. Chem. 446 (1993) 167.
[14] L.-C. Song, C.-G. Yan, Q.-M. Hu, B.-M. Wu, T.C.W. Mak,
Organometallics 16 (1997) 632.
[15] D. Seyferth, G.B. Womack, C.M. Archer, Organometallics 8
(1989) 443.
[16] L.-C. Song, G.-L. Lu, Q.-M. Hu, J. Sun, Organometallics 18
(1999) 2700.
Crystallographic data for the structural analyses have
been deposited with the Cambridge Crystallographic
Data Centre. CCDC no. 136084. Copies of this infor-
mation 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).
[17] J. Chen, C.L. Day, R.A. Jacobson, R.J. Angelici, J. Organomet.
Chem. 522 (1996) 21.
[18] Z. Qin, J. Sun, J. Chen, Organometallics 17 (1998) 600.
[19] Z.-X. Wang, C.-S. Jia, Z.-Y. Zhou, X.-G. Zhou, J. Organomet.
Chem. 580 (1999) 201.
Acknowledgements
[20] R.S. Atkinson, in: D. Barton, W.D. Ollis (Eds.), Comprehensive
Organic Chemistry, vol. 2, Pergamon Press, Oxford, 1979, p.
256.
We thank the Chinese Academy of Sciences and the
Educational Ministry of China for financial support.
[21] P. Gantzel, P.J. Walsh, Inorg. Chem. 37 (1998) 3450.
[22] S. Westhusin, P. Gantzel, P.J. Walsh, Inorg. Chem. 37 (1998)
5956.
[23] A. Singhal, V.K. Jain, M. Nethaji, A.G. Samuelson, D.
Jayaprakash, R.J. Butcher, Polyhedron 17 (1998) 3531.
[24] M.B. Hursthouse, M.A. Mazid, T. Clark, S.D. Robinson, Poly-
hedron 12 (1993) 563.
[25] M. Gomez, G. Muller, J. Sales, Polyhedron 12 (1993) 1171.
[26] N.G. Connelly, H. Daykin, Z. Demidowicz, J. Chem. Soc.
Dalton Trans. (1978) 1532.
[27] J.A. De Beer, R.J. Haines, J. Organomet. Chem. 24 (1970) 757.
[28] N.S. Nametkin, V.D. Tyurin, M.A. Kukina, J. Organomet.
Chem. 149 (1978) 355.
[29] E.D. Schermer, W.H. Baddley, J. Organomet. Chem. 30 (1971)
67.
[30] M.M. Bagga, P.E. Baikie, O.S. Mills, P.L. Pauson, J. Chem. Soc.
Chem. Commun. (1967) 1106.
[31] E.J. Wucherer, M. Tasi, B. Hansert, A.K. Powell, M.-T. Gar-
land, J.-F. Halet, J.-Y. Saillard, H. Vahrenkamp, Inorg. Chem.
28 (1989) 3564.
References
[1] D. Seyferth, G.B. Womack, J.C. Dewan, Organometallics 4
(1985) 508.
[2] D. Seyferth, G.B. Womack, J.C. Dewan, Organometallics 4
(1985) 398.
[3] D. Seyferth, J.B. Hoke, J.C. Dewan, Organometallics 6 (1987)
895.
[4] D. Seyferth, L.L. Anderson, W.M. Davis, J. Organomet. Chem.
459 (1993) 271.
[5] D. Seyferth, D.P. Ruschke, W.M. Davis, M. Cowie, A.D.
Hunter, Organometallics 13 (1994) 3834.
[6] D. Seyferth, L.L. Anderson, F. Villafane, M. Cowie, R.W. Hilts,
Organometallics 11 (1992) 3262.
[7] L.-C. Song, G.-L. Lu, Q.-M. Hu, X.-D. Qin, C.-X. Sun, J. Yang,
J. Sun, J. Organomet. Chem. 571 (1998) 55.
[8] L.-C. Song, C.-G. Yan, Q.-M. Hu, R.-J. Wang, T.C.W. Mak,
Organometallics 14 (1995) 5513.
[32] D.G. Foster, Organic Synthesis, Coll. vol. III, Wiley, New York,
1955, p. 771.
[9] L.-C. Song, C.-G. Yan, Q.-M. Hu, X.-Y. Huang, J. Organomet.
Chem. 505 (1995) 119.
[33] R.B. King, Organometallic Synthesis, vol. 1, Academic Press,
New York, 1965, p. 95.
[10] D. Seyferth, J.B. Hoke, D.R. Wheele, J. Organomet. Chem. 341
(1988) 421.
[34] N. Rabjohn, Organic Synthesis, Coll. vol. IV, Wiley, New York,
1963, p. 75.
[11] L.-C. Song, C.-G. Yan, Q.-M. Hu, R.-J. Wang, T.C.W. Mak,
X.-Y. Huang, Organometallics 15 (1996) 1535.
.