Synthesis of [(μ-RS)(μ-S){Fe2(CO)6}2(μ 4-S)]- and their reactivity toward electrophiles

Article abstract of DOI:10.1016/S0022-328X(98)01145-0

Reaction of the Et₃NH⁺ salts of the [(μ-RS)(μ-CO)Fe₂(CO)₆]^- anions (R = Bu^t, Ph or PhCH₂) with (μ-S₂)Fe₂(CO)₆ gives reactive intermediates [(μ-RS

Full text of DOI:10.1016/S0022-328X(98)01145-0

Journal of Organometallic Chemistry 580 (1999) 201–204
−
Synthesis of [(m-RS)(m-S){Fe (CO) } (m -S)] and their reactivity
2
6 2
4
toward electrophiles
a,
a
b
b
Zhong-Xia Wang *, Cheng-Sheng Jia , Zhong-Yuan Zhou , Xiang-Ge Zhou
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 Science, Chengdu 610041, PR China
Received 16 October 1998
Abstract
Reaction of the Et NH salts of the [(m-RS)(m-CO)Fe (CO) ] anions (R=Bu , Ph or PhCH ) with (m-S )Fe (CO) gives
+
−
t
3
2
6
2
2
2
6
−
reactive intermediates [(m-RS)(m-S){Fe (CO) } (m -S)] . Reactions of the latter with alkyl halides, acid chlorides and Cp(CO) FeI
have been studied. X-Ray structure of (m-Bu S)(m-PhCH S)[Fe (CO) ] (m -S) was determined. © 1999 Elsevier Science S.A. All
2
6
2
t
4
2
2
2
6 2
4
rights reserved.
Keywords: Iron; Bridging-sulfur ligand; Complexes; Synthesis; Reaction
1. Introduction
2. Results and discussion
−
The S–S bond of (m-S )Fe (CO) has been reported
Anionic complexes [(m-RS)(m-CO)Fe (CO) ] (A) are
2
2
6
2
6
to be cleaved readily by nucleophiles such as RLi or
known to act as metal-centred nucleophiles [5]. Treat-
−
RMgX, forming the monoanionic complexes [(m-RS)(m-
ment of (m-S )Fe (CO) with [(m-RS)(m-CO)Fe (CO) ]
2
2
6
2
6
−
S)Fe (CO) ] [1,2]. These anionic complexes showed
in THF at −78°C resulted in cleavage of the sulfur–
sulfur bond of (m-S )Fe (CO) , forming the tetranuclear
2
6
versatile reactivities toward electrophiles or oxidation
2
2
6
agents [2–4]. However, the reactions of (m-S )Fe (CO)
anionic complexes, presumably 1, in which the m-CO
ligand of A is replaced by one of the sulfur atoms of
(m-S )Fe (CO) , Scheme 1. The anions 1 with alkyl
2
2
6
with metallic nucleophiles have not been explored. In
this paper, we report the reaction of (m-S )Fe (CO)
2
2
6
2
2
6
−
1
with [(m-RS)(m-CO)Fe (CO) ] (A) and the reactivity of
halides afforded (m-RS)(m-R S)[Fe (CO) ] (m -S) (2–4)
2
6
2
6 2
4
2
the resulting complexes [(m-RS)(m-S){Fe (CO) } (m -
2
6
2
4
and with acid chlorides gave (m-RS)(m-R COS)–
−
S)] (1) toward electrophiles. These reactions provide a
[
Fe (CO) ] (m -S) (5–8). When the anions 1 were
2
6 2
4
general route for the synthesis of Fe–S cluster series
treated with Cp(CO) FeI, pentanuclear iron–sulfur
2
1
(
m-RS)(m-R S)[Fe (CO) ] (m -S) and also make possible
2
6 2
4
complexes 9–11 were obtained as black crystals. Com-
plexes 2–11 are air-stable in solid state, but slightly
air-sensitive in solution. They are very soluble in polar
organic solvents such as methylene chloride and soluble
in petroleum ether. Complexes 3 and 4 were previously
prepared by another route and identified by compari-
son of their melting points, NMR and IR spectral data
the preparation of complexes of types (m-RS)[m-
2
R C(O)S][Fe (CO) ] (m -S) and (m-RS)[m-Cp(CO) FeS]
2
6 2
4
2
[
Fe (CO) ] (m -S).
2
6 2
4
*
Corresponding author. Fax: +86-551-3631760.
E-mail address: zxwang@ustc.edu.cn (Z.-X. Wang)
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(98)01145-0

202
Z.-X. Wang et al. / Journal of Organometallic Chemistry 580 (1999) 201–204
to those authentic samples [6–8]. Each of complexes 2
and 5–11 gave satisfactory microanalytical, as well as
H-NMR and IR spectra and the data are in good
3. Experimental
1
All reactions were carried out under nitrogen using
standard Schlenk techniques. Tetra-hydrofuran (THF)
was distilled from sodium benzophenone ketyl.
agreement with the structures. For instance, the IR
spectra of complexes 2–11 showed terminal carbonyl
ligands. For complexes 5–8 the absorption bands of
+
−
[
Et NH]
[(m-RS)(m-CO)–Fe (CO) ]
[11] and (m-
3
2
6
1
S )Fe (CO) [12] were prepared by published proce-
ester carbonyls were also observed. The H-NMR spec-
2
2
6
dures. The progress of all reactions was monitored by
thin-layer chromatography. Infrared spectra (KBr disc)
were obtained by using a VECTOR22 spectrometer.
tra of the complexes showed that each of them exists
only one conformer, although there are four possible
conformational isomers according to the orientations of
the S–R and S–R% to the cluster core (Scheme 2). For
1
H-NMR spectra were recorded on either a Varian
1
EM360L or a Bruker DMX500 spectrometer with a
example, the H-NMR spectrum of complex 2 showed
t
CDCl
3
solvent. Elemental analyses were performed
a sharp Bu group signal at l 1.33 ppm and benzyl
with a 240C analyzer.
signals at lCH2 3.52 and lPh 7.20 ppm. However, the
NMR spectral data do not allow us to say which is
present. It seems that structure ii–iv are unfavored by
repulsions between the axial R (or R%) group and
terminal carbonyls.
1
3
.1. Preparation of (v-RS)(v-R S)[Fe (CO) ] (v -S) (2,
2
6 2
4
t
1
1
R=Bu , R =PhCH ; 3, R=Ph, R =Me; 4,
RꢀR =PhCH )
2
1
2
Complex 2 was characterised further by single crystal
X-ray diffraction. It crystallises in the triclinic crystal
system. The structure is presented in Fig. 1. Crystal
data and refinement are given in Table 1; selected bond
lengths and bond angles are listed in Table 2. The
structure shows that the molecule consists of doubly-
bridged Fe (CO) units sharing a common central sul-
A solution of triethylammonium salt of anion A was
generated by addition Fe (CO) (1.83 g, 3.63 mmol),
3
12
t
Bu SH (0.41 ml, 3.63 mmol) and Et N (0.51 ml, 3.66
3
mmol) in THF (50 ml) at room temperature under
nitrogen. The solution was cooled to −78°C. To the
solution was added (m-S )Fe (CO) (1.25 g, 3.63 mmol)
2
2
6
2
6
and stirred for 30 min at −78°C. Subsequently benzyl
chloride (0.46 g, 3.64 mmol) was syringed. The mixture
was warmed to room temperature and stirred
overnight. Solvent was removed at reduced pressure
and the residue extracted with petroleum ether. Filtra-
tion chromatography (silica gel; 10% CH Cl -
fur atom ligand. The two Fe (CO) units also bridge by
2
6
t
SBu ligand and SCH Ph ligand, respectively , and the
orientations of both Bu and CH Ph are equatorial. The
2
t
2
coordination about the central sulfur atom is distort-
edly tetrahedral. The molecular geometry is very similar
to those of the previously reported complexes, namely
symmetrical [(m-RS)Fe (CO) ] (m -S) (R=Me [9], Et
2
2
petroleum ether) gave red solid after evaporation of the
solvent, which was recrystallized from petroleum ether
to give red crystals of 2 (1.10 g, 38%). Anal. Found: C,
34.51; H, 2.22. C H Fe O S requires: C, 34.36; H,
2
6 2
4
1
[
(
6]) and the unsymmetrical (m-RS)(m-R S)[Fe (CO) ]
2
6 2
1
m -S) (R=ferrocenylmethyl, R =Me [10]; R=Ph,
1 1 n
4
23 16
4
12 3
1
R =Et [7] and R=Ph, R =Bu [8]).
2.01. m.p. 152–153°C. H-NMR: l (ppm) 1.33(s, 9H,
Scheme 1.

Z.-X. Wang et al. / Journal of Organometallic Chemistry 580 (1999) 201–204
203
Scheme 2.
t
−1
−1
Bu ), 3.52(s, 2H, CH ), 7.20(s, 5H, Ph). IR: w (cm
)
10H, Ph). IR: w (cm ) 2087s, 2055vs, 2038vs, 2005vs,
2
2080s, 2033vs, 2016vs, 1993vs, 1981vs (Fe–CO).
1991vs (Fe–CO), 1683m (PhCO).
Complex 3 was obtained similarly as red crystals in
4% yield, m.p. 136–138°C (lit. 134.5–135.5°C). H-
5
1
8
3.3. Preparation of (v-RS)[v-Cp(CO) FeS)-
2
t
NMR: l (ppm) 2.19(s, 3H, Me), 7.20(s, 5H, Ph). IR: w
[Fe
R=PhCH )
2
2
(CO)
6
]
2
(v
4
-S) (9, R=Bu ; 10, R=Ph; 11,
−
1
2
083s, 2050vs, 2035vs, 1989vs, 1971vs cm
CO).
Complex 4 was prepared similarly as red crystals in
(Fe–
t
To a cooled solution of [Et
(CO) [generated from Fe
mmol), Bu SH (0.14 ml, 1.24 mmol) and Et
NH][(m-Bu S)(m-CO)Fe
3
2
6
1
6
2% yield, m.p. 128–130°C (lit. 128–130°C). H-
6
]
3
(CO)12 (0.64 g, 1.27
N (0.20 ml,
t
NMR: l (ppm) 3.57(s, 2H, CH ), 7.21(s, 5H, Ph). IR:
3
2
−
1
w (cm ) 2083s, 2035vs, 2011s, 1986vs (Fe–CO).
1.43 mmol) in THF (30 ml) at room temperature]
was added (m-S )Fe (CO) (0.42 g, 1.22 mmol) and
2
2
6
2
stirred for 30 min at −78°C. Subsequently
3
(
.2. Preparation of (v-RS)[v-R C(O)S)[Fe (CO) ] -
2
6 2
t
2
2
Cp(CO) FeI (0.37 g, 1.38 mmol) was added. The re-
2
v -S) (5, R=Bu , R =Me; 6, R=Ph, R =Me; 7,
R=Bu , R =Ph; 8, RꢀR =Ph)
4
t
2
2
action was carried out and work-up as described in
Section 3.1. Complex 9 (0.30 g, 28%) was obtained as
black crystals. Anal. Found: C, 30.56; H, 1.60.
C H Fe O S requires: C, 31.05; H, 1.59. m.p.
t
To
a
cooled solution of [Et NH][(m-Bu S)(m-
CO)Fe (CO) ] generated from Fe (CO) (1.50 g, 2.98
mmol), Bu SH (0.34 ml, 2.98 mmol) and Et N (0.41
ml, 2.99 mmol) in THF (30 ml) was added (m-
S )Fe (CO) (1.00 g, 2.91 mmol) and stirred for 30
min at −78°C. Subsequently CH C(O)Cl (0.4 ml,
.64 mmol) was syringed. The mixture was warmed
3
2
3
14
5
14 3
2
6
3
12
1
t
1
5
1
54–155°C. H-NMR: l (ppm) 1.43(s, 9H, Bu ),
.10(s, 5H, Cp). IR: w (cm ) 2076s, 2053s, 2023vs,
t
3
−1
985s, 1967vs (Fe–CO).
2
2
6
Complexes 10 and 11 were prepared similarly.
Complex 10, black crystals in 24% yield. Anal.
3
3
Found: C, 33.13; H, 1.16. C H Fe O S requires: C,
2
5
10
5
14 3
to room temperature and stirred overnight. Work-up
as described in Section 3.1 gave red solid of complex
1
3
3.02; H, 1.11. m.p. 130–131°C. H-NMR: l (ppm)
5
in 49% yield. Anal. Found: C, 28.84; H, 1.69.
C H Fe O S requires: C, 28.60; H, 1.60. m.p. 129–
1
8
12
4
13 3
1
t
1
3
1
30°C. H-NMR: l (ppm) 1.45(s, 9H, Bu ), 2.54(s,
H, Me). IR: w (cm ) 2085s, 2055vs, 2035vs, 2014vs,
−
1
989vs, 1981vs (Fe–CO), 1731s (CH CO).
3
Complexes 6–8 were synthesized similarly. Complex
, dark red crystals in 42% yield. Anal. Found: C,
1.03; H, 1.16. C H Fe O S requires: C, 30.96; H,
6
3
1
3
2
2
0
8
4
1
13 3
.04. m.p. 130–132°C. H-NMR: l (ppm) 2.55 (s,
−
1
H, CH ), 7.20 (s, 5H, Ph). IR: w (cm ) 2087s,
3
036vs, 1998s, 1978s, 1969s (Fe–CO), 1732s
(
CH CO). Complex 7, dark red crystals in 68% yield.
3
Anal. Found: C, 34.04; H, 1.80. C H Fe O S re-
2
2
14
4
13 3
1
quires: C, 33.77; H, 1.73. m.p. 130–131°C. H-NMR:
l (ppm) 1.47 (s, 9H, Bu ), 7.17–7.60, 7.95–8.15 (m,
H, Ph). IR: w (cm ) 2085s, 2036vs, 1996vs, 1976s,
t
−
1
5
(
Fe–CO), 1680m (CH CO). Complex 8, red crystals
3
in 40% yield. Anal. Found: C, 36.30; H, 1.37.
C H Fe O S requires: C, 35.84; H, 1.19. m.p. 170–
2
3
14
4
13 3
1
1
72°C. H-NMR: l (ppm) 7.20–7.55, 7.90–8.20(m,
Fig. 1. ORTEP representation of the molecular structure of complex 2.

204
Z.-X. Wang et al. / Journal of Organometallic Chemistry 580 (1999) 201–204
Table 1
Table 2
Selected bond distances (A) and angles (°) for complex 2
˚
Crystal data and refinement for complex 2
˚
Formula
C23H16Fe O12S3
Distances (A)
4
M
803.94
Triclinic
P1
Fe(1)–S(1)
Fe(1)–S(2)
Fe(1)–Fe(2)
Fe(2)–S(1)
Fe(2)–S(2)
Fe(3)–S(1)
2.2433(7)
2.2536(8)
2.5283(6)
2.2454(8)
2.2719(8)
2.2411(8)
Fe(3)–S(3)
Fe(3)–Fe(4)
Fe(4)–S(1)
Fe(4)–S(3)
S(2)–C(13)
S(3)–C(20)
2.2683(7)
2.5309(8)
2.2572(8)
2.2713(7)
1.853(2)
1.865(2)
Crystal system
Space group
Unit cell dimensions
˚
a (A)
9.063(2)
11.422(3)
16.138(2)
105.09(2)
101.37(2)
94.87(2)
1564.9(6)
2
˚
b (A)
˚
c (A)
Angles (°)
h (°)
i (°)
k (°)
S(1)–Fe(1)–S(2)
S(1)–Fe(1)–Fe(2)
S(2)–Fe(1)–Fe(2)
S(1)–Fe(2)–S(2)
S(1)–Fe(2)–Fe(1)
S(2)–Fe(2)–Fe(1)
S(1)–Fe(3)–S(3)
S(1)–Fe(3)–Fe(4)
S(3)–Fe(3)–Fe(4)
S(1)–Fe(4)–S(3)
S(1)–Fe(4)–Fe(3)
S(3)–Fe(4)–Fe(3)
76.15(3)
55.76(2)
56.38(2)
75.74(3)
55.68(2)
55.69(2)
76.05(3)
56.06(2)
56.17(2)
75.68(2)
55.46(2)
56.06(2)
Fe(3)–S(1)–Fe(1)
Fe(3)–S(1)–Fe(2)
Fe(1)–S(1)–Fe(2)
Fe(3)–S(1)–Fe(4)
Fe(1)–S(1)–Fe(4)
Fe(2)–S(1)–Fe(4)
C(13)–S(2)–Fe(1)
C(13)–S(2)–Fe(2)
Fe(1)–S(2)–Fe(2)
C(20)–S(3)–Fe(3)
C(20)–S(3)Fe(4)
Fe(3)–S(3)Fe(4)
135.89(3)
135.93(3)
68.56(2)
68.47(3)
134.57(2)
125.45(3)
116.52(8)
115.61(8)
67.93(2)
121.56(8)
124.48(7)
67.77(2)
˚
3
U (A )
Z
Dcalc. (g cm−3)
Crystal size (mm)
1.706
0.38×0.32×0.26
0.71073
804
2.073
293(2)
5657
5657
3675
0.962
˚
Radiation u (A)
F(000)
v(Mo–K ) (mm−1)
a
Temperature (K)
Total reflections
Independent reflections
Reflections with I\2|(I)
Goodness-of-fit on F2
Final R indices [I\2|(I)]
lengths and angles have been deposited at the Cam-
bridge Crystallographic Data Centre.
a
R1
wR2
0.0457
0.1168
0.483 and −0.512
b
Largest differences peak and hole (e A−3)
˚
a
Acknowledgements
R =ꢀꢁꢁF ꢁ−ꢁF ꢁꢁ.
1
0
c
b
2
0
2 2
c
4 1/2
0
wR =[ꢀ w(F −F ) /ꢀ wF ]
.
2
We thank the Chinese Academy of Sciences and the
Educational Ministry of China for financial support.
−
1
5
2
.30(s, 5H, Cp), 7.40(s, 5H, Ph). IR: w (cm ) 2078s,
053s, 2028vs, 1991s, 1974s (Fe–CO). Complex 11,
black crystals in 25% yield. Anal. Found: C, 34.02; H,
1
1
5
2
.46. C H Fe O S requires: C, 33.80; H, 1.31. m.p.
References
2
6
12
5
14 3
1
70 °C (dec.). H-NMR: l (ppm) 3.60(s, 2H, CH ),
2
−
1
[
[
1] D. Seyferth, R.S. Henderson, J. Am. Chem. Soc. 101 (1979) 508.
2] D. Seyferth, R.S. Henderson, L.-C. Song, G.B. Womack, J.
Organomet. Chem. 292 (1985) 9.
.05(s, 5H, Cp), 7.20–7.26(b, 5H, Ph). IR: w (cm
.
)
075s, 2051s, 2038s, 2023vs, 2003vs, 1984s, 1972s, 1961s
(
Fe–CO).
[
[
3] D. Seyferth, A.M. Kiwan, J. Organomet. Chem. 286 (1985) 219.
4] D. Seyferth, L.-C. Song, R.S. Henderson, J. Am. Chem. Soc. 103
(1981) 5103.
3.4. Crystal data and structure determination
[
[
5] L.-C. Song, Chem. J. Chinese Univ. 17 (1996) 575.
6] L.-C. Song, M. Kadiata, J.-T. Wang, J. Organomet. Chem. 340
of complex 2
(
1988) 239.
Suitable crystals of complex 2 were grown from
petroleum ether=CH Cl solution at room tempera-
[
[
[
7] L.-C. Song, Q.-M. Hu, L.-Y. Zhang, H. Wang, Z.-Y. Zhou, L.
Liu, J. Organomet. Chem. 412 (1991) C19.
8] L.-C. Song, Q.-M. Hu, G.-F. Jia, J.-Y. Wang, Sci. Sinica B 35
2
2
ture. Data were collected on a Siemens P4 four-circle
diffractometer using monochromated Mo–Ka radia-
tion. A semi-empirical absorption correction was ap-
plied to the data. Structure was solved by direct method
(
1992) 1 (English Ed.).
9] J.M. Coleman, A. Wojcicki, P.J. Pollick, L.F. Dahl, Inorg.
Chem. 6 (1967) 1236.
[10] D. Seyferth, G.B. Womack, J.C. Dewan, Organometallics 8
(1989) 430.
11] D. Seyferth, G.B. Womack, C.M. Archer, J.C. Dewan,
Organometallics 4 (1985) 398.
12] D. Seyferth, R.S. Henderson, L.-C. Song, Organometallics 1
(1982) 125.
2
and was refined by full-matrix least-squares on F with
[
the positional and anisotropic thermal parameters on a
PC using Siemens SHELXTL software package.
Atomic coordinates, thermal parameters and bond
[