Reaction of [μ-RE(μ-CO)Fe2(CO)6]- (E = S, Se) with N2CHCO2Me. Synthesis and characterisation of (μ-RE)[μ-η2-N=NCH(R′)CO2Me]Fe 2(CO)6 and (μ-PhSe)[μ-η1<

Article abstract of DOI:10.1016/S0022-328X(00)00246-1

Reaction of [M][(μ-RE)(μ-CO)Fe₂(CO)₆] (E = S, Se; M = Et₃NH, Na) with N2CHCO2Me give the intermediate [M][(μ-RE)(μ-N₂CHCO₂Me)Fe₂(CO) ₆] (II). Action of II with counterion Et

Full text of DOI:10.1016/S0022-328X(00)00246-1

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 604 (2000) 214–218
Reaction of [(m-RE)(m-CO)Fe2(CO)6]− (E=S, Se) with
N2CHCO2Me. Synthesis and characterisation of
(m-RE)[m-h2-NꢀNCH(R%)CO2Me]Fe2(CO)6 and
(m-PhSe)[m-h1-NꢀNCH(Me)CO2Me]Fe2(CO)6
Zhong-Xia Wang a,*, Shao-Bin Miao a, Ze-Ying Zhang b
a Department of Chemistry, Uni6ersity of Science and Technology of China, Hefei, Anhui 230026, PR China
b Department of Chemistry, Peking Uni6ersity, Beijing 100871, PR China
Received 15 February 2000; accepted 18 April 2000
Abstract
Reaction of [M][(m-RE)(m-CO)Fe2(CO)6] (E=S, Se; M=Et3NH, Na) with N2CHCO2Me give the intermediate [M][(m-RE)(m-
N2CHCO2Me)Fe2(CO)6] (II). Action of II with counterion Et3NH+ yields neutral complexes (m-RE)(m-h2-
NꢀNCH2CO2Me)Fe2(CO)6 (1, RE=ButS; 2, RE=PhS; 3, RE=PhSe). Treatment of II (MꢀNa) with MeI affords
(m-RE)[m-h2-NꢀNCH(Me)CO2Me]Fe2(CO)6 (4, RE=ButS; 5, RE=PhS). In the case of RE=PhSe, the reaction of II with MeI
gives two isomers, (m-PhSe)[m-h2-NꢀNCH(Me)CO2Me]Fe2(CO)6 (6) and (m-PhSe)[m-h1-NꢀNCH(Me)CO2Me]Fe2(CO)6 (7). The
structure of complex 7 has been determined by single-crystal X-ray diffraction technique. © 2000 Elsevier Science S.A. All rights
reserved.
Keywords: Iron; Selenium; Sulfur; Diazenido ligand; Complex; Synthesis; Structure
[M][(m-RE)(m-CO)Fe2(CO)6] (M=Et3NH, Na) with
N2CHCO2Me. Herein we report the results.
1. Introduction
We have reported the reaction of [Et3NH][(m-RE)(m-
CO)Fe2(CO)6] (E=S, Se) with aryl azides, ArN3, form-
ing triazenido diiron complexes (I) [1]. Diazo
compounds bear a formal and chemical similarity to
azides and can react with good nucleophiles such as
RMgCl and R3P [2]. Hence, diazo compounds are also
anticipated to react with nucleophilic complexes [(m-
RE)(m-CO)Fe2(CO)6]− and the expected products
would be diazenido (N2R) diiron complexes. Although
many mononuclear diazenido complexes are known,
compounds in which the diazenido ligand bridges
a metalꢁmetal bond are relatively rare [3,4]. In order
to prepare new multinuclear diazenido complexes
and study the coordination modes of diazenido lig-
and at metal centres, we investigated the reaction of
2. Results and discussion
The reaction of [M][(m-RE)(m-CO)Fe2(CO)6] with
N2CHCO2Me and the synthesis of complexes (m-RE)[m-
h2-NꢀNCH(R%)CO2Me]Fe2(CO)6 and (m-PhSe)[m-h1-
NꢀNCH(Me)CO2Me]Fe2(CO)6 are summarised in
Scheme 1. When N2CHCO2Me was added to a solution
* Corresponding author. Fax: +86-551-3631760.
E-mail address: zxwang@ustc.edu.cn (Z.-X. Wang).
Scheme 1.
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(00)00246-1

Z.-X. Wang et al. / Journal of Organometallic Chemistry 604 (2000) 214–218
215
pair of a-nitrogen (for IIa) or b-nitrogen (for IIb) and
concomitant loss of the m-CO ligand.
Attempts to isomerise the h1- and h2-bridged isomers
were unsuccessful although a related reversible photo-
chemical/thermal interconversion of h1- and h2-bridged
(aryldiazo)triosmium clusters, (m-H)(m-N2Ar)Os3(CO)10,
has been reported [5]. Heating complexes (m-RE)[m-h2-
NꢀNCH(R%)CO2Me]Fe2(CO)6 in benzene gave (m-
RE)2Fe2(CO)6 and decomposed species.
Fig. 1. ORTEP representation of the molecular structure of complex 7.
Complexes (m-RE)2Fe2(CO)6 (RE=ButS, PhS and
PhSe) are known and have been identified by compari-
Table 1
1
,
Selected bond distances (A) and angles (°) for complex 7
son of their melting points, IR and H-NMR spectra
with those of authentic samples [6–8].
Bond distances
Complexes 1–7 are deep red or brown red solids (1,
4 and 7) or viscous oil (2, 3, 5 and 6) and have been
Fe(1)ꢁN(1)
Fe(1)ꢁSe(1)
Fe(1)ꢁFe(2)
1.915(10)
2.397(3)
2.458(3)
Fe(2)ꢁN(1)
Fe(2)ꢁSe(1)
N(1)ꢁN(2)
1.986(13)
2.395(2)
1.193(15)
1
characterised by elemental analyses, H-NMR and IR
1
spectra. The H-NMR spectrum of each of complexes
Bond angles
1–3 displayed two inequivalent proton signals for CH2
group and signals for RE and OMe groups. The H-
NMR spectra of complexes 4–7 exhibited the respective
N(1)ꢁFe(1)ꢁSe(1)
N(1)ꢁFe(1)ꢁFe(2)
Se(1)ꢁFe(1)ꢁFe(2)
Fe(1)ꢁSe(1)ꢁFe(2)
N(2)ꢁN(1)ꢁFe(1)
C(1)ꢁSe(1)ꢁFe(1)
82.5(4)
52.2(4)
59.10(8)
61.71(8)
136.6(11)
109.1(3)
N(1)ꢁFe(2)ꢁSe(1)
N(1)ꢁFe(2)ꢁFe(1)
Se(1)ꢁFe(2)ꢁFe(1)
N(1)ꢁN(2)ꢁC(13)
N(2)ꢁN(1)ꢁFe(2)
Fe(2)ꢁN(1)ꢁFe(1)
81.2(4)
49.7(3)
59.19(8)
112.5(13)
145.3(10)
78.1(4)
1
signals for CHMe group and RE and OMe groups. In
1
addition, the H-NMR spectrum of complex 7 showed
that the chemical shifts of CHMe group appeared at
higher field than corresponding those of complexes
4–6. The IR spectra of these complexes all gave NꢀN,
carboxylato group and terminal carbonyl absorption
bands. The NꢀN absorption for h1-diazenido ligand
appeared at 1557 cm−1, and the bands for h2-diazenido
ligands were in the range of 1567–1578 cm−1. Al-
though the NꢀN absorptions of complexes 1 and 4 are
between that of complex 7 and those of the h2-com-
plexes (2, 3, 5 and 6), their 1H-NMR spectra are
consistent with those of h2-complexes. For example, the
chemical shifts of CHMe group at l 1.45 ppm and l
4.20–4.55 ppm for complex 4 were close to those of
complex 6 (l 1.35–1.60 and l 3.75–4.10 ppm) rather
than those of complex 7 (l 0.75 and l 3.10–3.40 ppm).
Attempts to grow the single crystals of complexes 1–6
for X-ray analyses were unsuccessful. However, com-
plex 7 has been characterised by single-crystal X-ray
diffraction. The structure is presented in Fig. 1, and the
selected bond lengths and angles are in Table 1. The
molecule is a diiron hexacarbonyl complex with both
of [M][(m-RE)(m-CO)Fe2(CO)6] (E=S, Se) at room
temperature, a reaction occurred, with gas evolution
and colour change from brown–red to red–orange in a
few minutes. In the case of M=Et3NH, complexes
(m-RE)(m-h2-NꢀNCH2CO2Me)Fe2(CO)6 (1–3) were iso-
lated after stirring overnight. When M=Na, the reac-
tion mixture of [M][(m-RE)(m-CO)Fe2(CO)6] and
N2CHCO2Me was further treated with MeI to give
(m-RE)[m-h2-NꢀNCH(Me)CO2Me]Fe2(CO)6 (4–6) and
(m-RE)[m-h1-NꢀNCH(Me)CO2Me]Fe2(CO)6 (7, RE=
PhSe). In addition, (m-RE)2Fe2(CO)6 was also produced
in each reaction. The formation of complexes 1–6 and
complex 7 could be through anionic intermediates IIa
(for 1–6) and IIb (for 7), respectively, which formed by
nucleophilic attack of the iron atoms of [(m-RE)(m-
CO)Fe2(CO)6]− at the terminal nitrogen of
N2CHCO2Me, followed by coordination of the lone

216
Z.-X. Wang et al. / Journal of Organometallic Chemistry 604 (2000) 214–218
PhSe ligand and h1-NꢀNCH(Me)CO2Me ligand bridg-
ing the two metals. The two metal atoms [Fe(1)Fe(2)]
and the two nitrogen atoms [N(1)N(2)] are coplanar
[the sum of the angles around N(1) is 360°]. The
orientation of phenyl group is axial. The N(1) binds
two iron atoms in a little asymmetrical manner
1.16 g (2.30 mmol) of Fe3(CO)12, 0.26 ml (2.30 mmol)
of ButSH and 0.33 ml (2.36 mmol) of Et3N in 30 ml of
THF at room temperature (r.t.). To the solution was
added 0.23 g (2.30 mmol) of N2CHCO2Me with stir-
ring. After stirring overnight, the solvent was removed
at reduced pressure and the residue extracted with 2:8
(v/v) CH2Cl2–petroleum ether. After removal of the
solvent, the material remaining was subjected to filtra-
tion chromatography (silica gel). Petroleum ether eluted
a first band which gave, after recrystallisation from
petroleum ether, 0.04 g (8%) of (m-ButS)2Fe2(CO)6 [6] as
red crystals. Further elution with 2:3 (v/v) CH2Cl2–
petroleum ether followed by evaporation of the solvent
gave 0.86 g (80%) of red solid 1, m.p. 50–52°C. Anal.
Found: C, 33.46; H, 3.05; N, 6.06. Calc. for
C13H14Fe2N2O8S: C, 33.22; H, 3.00; N, 5.96%. 1H-
NMR (CDCl3): l (ppm) 1.02 (s, 9H, But), 3.75 (s, 3H,
,
[N(1)ꢁFe distances 1.915(10) and 1.986(13) A, respec-
tively]. While the Se atom is bound almost symmetri-
cally across the metals and the FeꢁSe bond lengths
,
[2.395(2) and 2.397(3) A, respectively] are comparable
to those of (m-PhSe)(m-PhCH2SCꢀS)Fe2(CO)6 (av. 2.374
,
,
A) [9] and (m-Se2)Fe2(CO)6 (av. 2.364 A) [10]. The
,
Fe(1)ꢁFe(2) distance of 2.458(3) A is very close to that
,
of complex 8 [2.459(1) A] [11]. The FeꢁN distances (av.
1.95 A) is also close to those of complex 8 (av. 1.969
,
,
A), but longer than those found in complex 9 (av. 1.863
,
,
A) [12]. The NꢁN bond length of 1.193(15) A is shorter
than those of related h1-diazenido transition metal
Me), 4.33, 4.77 (s, s, 2H, CH2). IR (KBr disc): w (cm−1
)
1
,
complexes such as complex 9 [1.238(3) A], [(m-h -
2074vs, 2036vs, 2012vs, 1987vs, 1965vs (FeꢁCO); 1753s
(CO); 1567s (NꢀN).
1
,
NꢀNPh)Mn(CO)4]2 [1.234(3) A] [13] and (m-H)[m-h -
,
NꢀN(p-tol)]Os3(CO)10 [1.238(18) A] [14], close to those
Compound 2 was prepared according to the same
procedure as for 1, but PhSH was used instead of
ButSH. After similar work-up, (m-PhS)2Fe2(CO)6 (37%)
[7] and 2 (61%) were obtained. 2, deep red oil. Anal.
Found: C, 37.08; H, 2.20; N, 5.64. Calc. for
C15H10Fe2N2O8S: C, 36.77; H, 2.06; N, 5.72%. 1H-
NMR (CDCl3): l (ppm) 3.70 (s, 3H, Me), 3.96, 4.10 (s,
of h2-diazenido complexes (m-H)(m-h2-NꢀNPh)-
2
,
Os3(CO)10 [1.20(4) A] [5] and [(C5Me5)2Ir2(CO)2(m-h -
,
NꢀNC6H4OMe)][BF4] [1.205(9) A] [3].
s, 2H, CH2), 7.10 (s, 5H, Ph). IR (CCl4): w (cm−1
)
2078vs, 2048vs, 1990vs (FeꢁCO); 1748s (CO); 1576s
(NꢀN).
Compound 3 was prepared according to the same
procedure as for 1, but PhSeH was used instead of
ButSH. After similar work-up, (v-PhSe)2Fe2(CO)6
(33%) [8] and complex 3 (63%) were obtained. 3, deep
red oil. Anal. Found: C, 33.82; H, 2.04; N, 5.63. Calc.
for C15H10Fe2N2O8Se: C, 33.56; H, 1.88; N, 5.22%.
1H-NMR (CCl4): l (ppm) 3.65 (s, 3H, Me), 3.95, 4.20
3. Experimental
(s, s, 2H, CH2), 7.05 (s, 5H, Ph). IR (CCl4): w (cm−1
)
All reactions were carried out under nitrogen using
standard Schlenk techniques. Tetrahydrofuran (THF)
was distilled from sodium benzophenone ketyl. PhSeH
[15], Fe3(CO)12 [16] and N2CHCO2Me [17] were ob-
tained by published procedures. The solutions of
2073vs, 2031vs, 1988vs (FeꢁCO); 1748s (CO); 1575s
(NꢀN).
3.2. Synthesis of (v-RS)[v-p2-NꢀNCH(Me)CO2Me]-
Fe2(CO)6 (4, R=But; 5, R=Ph)
[M][(m-RS)(m-CO)Fe2(CO)6]
and
[M][(m-PhSe)(m-
CO)Fe2(CO)6] were prepared by the methods described
in literatures [9,18]. 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 per-
formed with a 240C analyser.
To a solution of [Na][(m-RS)(m-CO)Fe2(CO)6] gener-
ated from 1.0 g (1.98 mmol) of Fe3(CO)12 and an
equimolar amount of ButSNa (from ButSH and NaH)
in 30 ml of THF was added 0.2 g (2.0 mmol) of
N2CHCO2Me and stirred for 30 min at r.t. To the
mixture 0.3 ml (4.81 mmol) of MeI was added and
stirred overnight. The solvent was removed at reduced
pressure and the residue extracted with 2:8 (v/v)
CH2Cl2–petroleum ether. After removal of the solvent,
the material remaining was subjected to filtration chro-
matography (silica gel). Elution with petroleum ether
3.1. Synthesis of (v-RE)(v-p2-NꢀNCH2CO2Me)-
Fe2(CO)6 (1, RE=ButS; 2, RE=PhS; 3, RE=PhSe)
A solution of the triethylammonium salt of [(m-
ButS)(m-CO)Fe2(CO)6]− was generated by the reacting

Z.-X. Wang et al. / Journal of Organometallic Chemistry 604 (2000) 214–218
217
yielded, after recrystallisation from petroleum ether,
0.06 g (13%) of red crystalline (m-ButS)2Fe2(CO)6 [6].
Further elution with 2:3 (v/v) CH2Cl2–petroleum ether
followed by evaporation of the solvent and recrystalli-
sation from CH2Cl2–petroleum ether gave 0.66 g (69%)
of brown red crystalline 4, m.p. 50–52°C. Anal. Found:
C, 34.64; H, 3.25; N, 5.88. Calc. for C14H16Fe2N2O8S:
C, 34.74; H, 3.33; N, 5.79%. 1H-NMR (CDCl3): l
(ppm) 1.05 (s, 9H, But), 1.45 (d, J=6 Hz, 3H, Me),
3.75 (s, 3H, Me), 4.20–4.55 (m, 1H, CH). IR (CCl4): w
(cm−1) 2075vs, 2032vs, 1989vs (FeꢁCO); 1750s (CO);
1568s (NꢀN).
Compound 5 was prepared according to the same
procedure as for 4, but PhSH was used instead of
ButSH. After similar work-up, (m-PhS)2Fe2(CO)6 (26%)
[7] and 5 (30%) were obtained. 5, deep red oil. Anal.
Found: C, 38.30; H, 2.35; N, 5.70. Calc. for
C16H12Fe2N2O8S: C, 38.13; H, 2.40; N, 5.56%. 1H-
NMR (CDCl3): l (ppm) 1.22–1.45 (b, 3H, Me), 3.65 (s,
3H, Me), 3.90–4.40 (m, 1H, CH), 7.10 (s, 5H, Ph). IR
(CCl4): w (cm−1) 2078vs, 2037vs, 2000vs (FeꢁCO);
1749s (CO); 1578s (NꢀN).
equimolar amount of PhSeNa (from PhSeH and NaH)
in 30 ml of THF was added 0.2 g (2.0 mmol) of
N2CHCO2Me and stirred for 40 min at r.t. To the
mixture 0.3 ml (4.81 mmol) of MeI was added and
stirred overnight. The solvent was removed at reduced
pressure and the residue extracted with 2:8 (v/v)
CH2Cl2–petroleum ether. After removal of the solvent,
the material remaining was subjected to filtration chro-
matography (silica gel). Elution with petroleum ether
yielded, after recrystallisation from petroleum ether,
0.11
g
(19%) of brown red crystalline (m-
PhSe)2Fe2(CO)6 [8]. Further elution with 2:3 (v/v)
CH2Cl2–petroleum ether developed two red bands suc-
cessively. The two bands gave, after evaporation of the
solvent and recrystallisation from CH2Cl2–petroleum
ether, 0.13 g (12%) of 7 and 0.19 g (18%) 6, respec-
tively. 7, brown red crystals, m.p. 84–86°C. Anal.
Found: C, 34.91; H, 2.14; N, 4.82. Calc. for
C16H12Fe2N2O8Se: C, 34.88; H, 2.20; N, 5.08%. 1H-
NMR (CDCl3): l (ppm) 0.75 (d, J=7 Hz, 3H, Me),
3.10–3.40 (m, 1H, CH), 3.65 (s, 3H, Me), 7.20 (s, 5H,
Ph). IR (KBr disc): w (cm−1) 2070vs, 2032vs, 1998vs,
1981vs (FeꢁCO); 1745s (CO); 1557m (NꢀN). 6, deep
red oil. Anal. Found: C, 34.67; H, 2.27; N, 4.97. Calc.
for C16H12Fe2N2O8Se: C, 34.88; H, 2.20; N, 5.08%.
1H-NMR (CDCl3): l (ppm) 1.35–1.60 (b, 3H, Me),
3.68 (s, 3H, Me), 3.75–4.10 (m, 1H, CH), 7.20 (s, 5H,
Ph). IR (CCl4): w (cm−1) 2073vs, 2032vs, 1995vs
(FeꢁCO); 1748s (CO); 1575s (NꢀN).
3.3. Synthesis of (v-PhSe)[v-p2-NꢀNCH(Me)CO2-
Me]Fe2(CO)6 (6) and (v-PhSe)[v-p1-NꢀNCH(Me)-
CO2Me]Fe2(CO)6 (7)
To a solution of [Na][(m-PhSe)(m-CO)Fe2(CO)6] gen-
erated from 1.0 g (1.98 mmol) of Fe3(CO)12 and an
Table 2
3.4. Crystal data and structure determination of
complex 7
Crystal data and refinement for complex 7
Formula
C16H12Fe2N2O8Se
550.94
Triclinic
Suitable crystals of complex 7 were grown from
petroleum ether–CH2Cl2 solution at r.t. Data were
collected on an IP Rigaku diffractometer using
graphite-monochromated Mo–Ka radiation. Structure
was solved by direct method and refined by full-matrix
least-squares on F2 with anisotropic thermal parame-
ters for non-hydrogen atoms on a PC using SHELXS-97
[19] and SHELXL-97 [20], respectively. A summary of
crystal data and refinement parameters is given in Table
2. The high value of R is attributed to the relatively
poor quality of the crystal resulting in a weak set of
data.
Formula weight
Crystal system
Space group
(
P1
,
a (A)
7.7488(15)
16.761(3)
18.373(4)
116.27(3)
95.83(3)
97.83(3)
2084.3(7)
4
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
3
,
V (A )
Z
Crystal size (mm)
Radiation u (A)
Temperature (K)
2qmax (°)
0.40×0.40×0.05
0.71073
293(2)
,
51.26
Total reflections
2858
Independent reflections
Reflections with [I\2|(I)]
Goodness-of-fit on F2
Final R indices [I\2|(I)]
2858
2368
1.299
4. Supplementary material
a
R1
wR2
0.0969
0.2696
1.292 and −1.498
Crystallographic data for the structural analyses have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC no. 140437. Copies of this infor-
mation may be obtained free of charge from The
Director, CCDC, 12 Union Road, Cambridge CB2
b
−3
,
Largest differences peak and hole (e A
)
a R1=ꢀꢁꢁFoꢁ−ꢁFcꢁꢁ/ꢀꢁFoꢁ.
b wR2=[ꢀw(Fo2−Fc2)2/ꢀ wFo4]1/2
.

218
Z.-X. Wang et al. / Journal of Organometallic Chemistry 604 (2000) 214–218
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cam.ac.uk).
[9] L.-C. Song, C.-G. Yan, Q.-M. Hu, R.-J. Wang, T.C.W. Mak,
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Acknowledgements
[11] A.J. Mayr, K.H. Pannell, B. Carrasco-Flores, F. Cervantes-Lee,
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We thank the Chinese Academy of Sciences and the
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