Synthesis and structures of bis(alkene) complexes of tungsten and molybdenum, [M(CO)2(dpphen)(dbf)2] (M = W or Mo; dpphen = 4,7-diphenyl-1,10-phenanthroline; dbf = dibutylfumarate)

Article abstract of DOI:10.1002/1521-3749(200111)627:11<2481::AID-ZAAC2481>3.0.CO;2-B

Tungsten and molybdenum complexes [M(CO)₂-(dpphen)(dbf)₂] (M = W 1 or Mo 2; dpphen = 4,7-diphenyl-1,10-phenanthroline; dbf = dibutylfumarate) have been synthesized and structurally characterized by X-ray diffraction analysis. In both

Full text of DOI:10.1002/1521-3749(200111)627:11<2481::AID-ZAAC2481>3.0.CO;2-B

Synthesis and Structures of Bisꢀalkene) Complexes of Tungsten
and Molybdenum, [MꢀCO)2ꢀdpphen)ꢀdbf)2] ꢀM = W or Mo;
dpphen = 4,7-diphenyl-1,10-phenanthroline; dbf = dibutylfumarate)
Xiangjin Xie, Xianglin Jin, and Kaluo Tang*
Beijing/P. R. China, Institute of Physical Chemistry, Peking University
Received April 26th, 2001.
Abstract. Tungsten and molybdenum complexes [M)CO)2-
)dpphen))dbf)2] )M = W 1 or Mo 2; dpphen = 4,7-diphenyl-
1,10-phenanthroline; dbf = dibutylfumarate) have been
synthesized and structurally characterized by X-ray diffrac-
tion analysis. In both complexes which have similar struc-
ture, the metal atom co-ordination is distorted octahedral
with dpphen and two CO groups in the equatorial plane and
the metal atom binds in an g2-fashion to the C±C bonds of
two dbf ligands. The two C±C bonds are almost mutually
orthogonal. The two complexes are different in conforma-
tion which result from face selection of the two dbf ligands
for coordination to the metal atom.
Keywords: Molybdenum; Tungsten; 4,7-Diphenyl-1,10-phen-
anthroline; Dibutylfumarate; Crystal structure
Synthese und Strukturen von Bisꢀalken)-Komplexen von Wolfram
und MolybdaÈn, [MꢀCO)2ꢀdpphen)ꢀdbf)2] ꢀM = W oder Mo;
dpphen = 4,7-Diphenyl-1,10-phenanthrolin; dbf = Dibutylfumarat)
InhaltsuÈbersicht. Die Wolfram- und MolybdaÈn-Komplexe
[M)CO)2)dpphen))dbf)2] )M = W 1 oder Mo 2; dpphen =
4,7-Diphenyl-1,10-phenanthrolin; dbf = Dibutylfumarat) wur-
den synthetisiert und durch roÈntgenographische Kristall-
strukturanalysen charakterisiert. Beide Komplexe haben
aÈhnliche Strukturen; die Metall-Atome sind verzerrt okta-
edrisch mit dem dpphen-Liganden und zwei CO-Gruppen
aÈquatorial und mit den g2-gebundenen C±C-Bindungen der
beiden dbf-Liganden koordiniert. Die beiden C±C-Bindun-
gen stehen nahezu orthogonal zueinander. Die Konforma-
tion der beiden Komplexe ist bezuÈglich der relativen Anord-
nung der dbf-Liganden am Metall-Atom verschieden.
1
Introduction
dichlorobenzene. Crystals suitable for X-ray diffraction
have not been obtained. However, when one carbonyl
group of [M)g2-C60))CO)3)NN)] was displaced by dbf,
as was expected, the resulting complexes [M)g2-C60)-
)CO)2)phen))dbf)] have good solubility in a number of
organic solvents and their structures were determined
by X-ray diffraction [6, 7]. If dbf is displaced by an-
other C60 ligand, we can obtain dumb-bell [M)g2-C60)2-
)CO)2)NN)] complexes which are expected to have
better optical or electric properties than [M)g2-C60)-
)CO)2)phen))dbf)] [8±10]. But the key problem is still
the poor solubility of the dumb-bell complexes, making
them difficult to analyze and use in applications. How-
ever, when two phenyl groups were introduced in 1,10-
phenanthroline, we obtained the title complexes which
have better solubility than [M)CO)2)phen))dbf)2]. They
could be the precursor for further reaction with
fullerenes to obtain dumb-bell complexes which are ex-
pected to have good solubility.
Octahedral tungsten and molybdenum complexes with
binitrogen-containing ligand and trans-bis)alkene) or
bis)alkyne) have attracted considerable attention both
theoretically and experimentally. The main focus has
generally been on the conformation and the mecha-
nism of the rotation of the trans-bis)alkene) or bis-
)alkyne) [1±4]. Here we report the synthesis and char-
acterization of tungsten and molybdenum bis)alkene)
complexes [M)CO)2)dpphen))dbf)2] )M = W 1 or Mo 2)
with the interest in solving the low solubility of ful-
lerene complexes.
We have previously synthesized four air-stable C60
derivatives of tungsten)0) and molybdenum)0)
[M)g2-C60))CO)3)NN)] )M = W or Mo; NN = 2,2'-
bipyridine)bipy) or 1,10-phenanthroline)phen)) [5].
They are sparingly soluble in chlorobenzene and o-
* Prof. Kaluo Tang,
Institute of Physical Chemistry,
Peking University,
2Experimental
Beijing, 100871/P. R. China
e-mail: jt1939@pku.edu.cn
All reactions were carried out under a nitrogen atmosphere
with standard Schlenk technique. Dibutylmaleate )dbm) and
Z. Anorg. Allg. Chem. 2001, 627, 2481±2485 Ó WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2001 0044±2313/01/6272481±2485 $ 17.50+.50/0 2481

Xiangjin Xie, Xianglin Jin, Kaluo Tang
4,7-diphenyl-1,10-phenanthroline were purchased from Bei-
jing Xu Dong and ACROS, respectively, and were not
further purified before using. The complexes [M)CO)4)dp-
phen)] [M = W or Mo] were prepared according to the litera-
ture [11]. Infrared spectra were recorded from KBr pellets
with a Nicolet-550 spectrometer )scanning scope 4000±
400 cm±1). Elemental analyses are performed by Elementar
Vario EL )Germany) for complex 1 and by Carlo Erba
110698ST)4)P60 for complex 2.
Table 1 Crystal data and structure refinement for complex
1 and 2
Complex 1
Complex 2
Empirical formula
M
Color
C50H56N2O10
1028.82
red
W
C50H56N2O10Mo
940.91
orange
Crystal size/mm
Crystal system
Space group
0.40 ´ 0.10 ´ 0.10
monoclinic
P 2)1)/n
17.702)4)
13.400)3)
19.453)4)
90
96.38)3)
90
4
0.80 ´ 0.60 ´ 0.40
monoclinic
P 2)1)
13.709)2)
12.178)1)
14.168)2)
90
104.317)4)
90
2
Ê
a/A
Ê
b/A
Ê
Preparations
c/A
a/°
Complex 1. Dibutylmaleate )0.25 ml, 1 mmol) was added to
a solution of [W)CO)4)dpphen)] )209 mg, 0.33 mmol) in
toluene )20 mL) and refluxed for 24 h, then concentrated.
The resulting solution was separated by column chromato-
graphy )silica gel) using benzene/acetone )14 : 1) as eluent.
The main chromatography band was collected. The solvents
were removed and the residue dried in vacuo to give yellow
powder )198 mg, 58%). Crystals suitable for X-ray diffrac-
tion analysis were obtained by slow diffusion of petroleum
ether )30±60 °C) into an acetone solution. {Found: C, 58.17;
H, 5.48; N, 2.61; calc. for C50H56N2O10W: C, 58.37; H, 5.49;
N, 2.72%.}
b/°
c/°
Z
Dc/)g ´ cm±3
)
1.490
2.580
4585.8)17)
2096
1.363
0.347
2292.0)4)
984
l/mm±1
3
Ê
V/A
F)000)
2h range/°
2.24±27.48
0.7726, 0.4595
10451
2.49±25.00
0.5810, 0.1653
4187
Max., min. transmission
No. unique reflections
Rint
0.0739
0.0883
No. observed reflections, Fo > 4r
7374
3745
Data/restraints/parameters
10451/0/589
±1.708, 1.419
95.4%
0.0355
0.06820.1598
0.929
4187/4/572
±0.889, 0.904
98.4%
±3
Ê
qmin, qmax/)e ´ A
)
Completeness to 2h = 27.48
R1 = R||)Fo| ± |Fc||/R|Fo|, I > 2r)I)
wR2 = {R[w)Fo2 ± F2c)2]/R[)Fo2)2]}1/2
Goodness of fit, GooF = S =
{R[w)Fo2 ± F2c)2]/)n ± p)}1/2
0.0571
IR )KBr): 3036 vw, 2959 s, 2871 m, 1980 vs, 1910 vs, 1690 vs, 1624 w,
1596 vw, 1560 vw, 1519 vw, 1447 s, 1418 w, 1387 w, 1286 s, 1148 vs, 1067 m,
1.008
1026 m, 856 w, 806 vw, 765 m, 741 w, 700 m, 555 w, 496 vw, 441 w cm±1
.
Complex 2. Dibutylmaleate )0.15 ml, 0.6 mmol) was added to
a solution of [Mo)CO)4)dpphen)] )108 mg, 0.2mmol) in to-
luene )10 mL) and refluxed for 21 h, then concentrated. The
resulting solution was separated by column chromatography
)silica gel) using benzene/acetone )10 : 1) as eluent. The main
chromatography band was collected. The solvents were re-
moved and the residue dried in vacuo to give yellow powder
)117 mg, 63%). Crystals suitable for X-ray diffraction analy-
sis were obtained by slow diffusion of petroleum ether )30±
60 °C) into an acetone solution. {Found: C, 64.19; H, 5.94;
N, 2.38; calc. for C50H56N2O10W: C, 63.82; H, 6.00; N, 2.98%.}.
±3
Ê
ference Fourier unknown peak )1.419 e ´ A ) is near the
W-atom with the distance of 0.837A.
Ê
Further details of the crystal structure investigation are
available from the Cambridge Crystallography Data Center
)CCDC). CCDC reference number 162021 for complex 1
and 162022 for complex 2.
3
Results and Discussion
IR )KBr): 3059 vw, 2957 s, 2870 m, 1980 vs, 1913 vs, 1691 vs, 1622 w,
The crystal structure analysis indicates that the mole-
cular structures of complex 1 and 2, [M)CO)2)dpphen)-
)dbf)2] [M = W 1 or Mo 2] have similar structure ex-
cept that different faces of dbf ligands are coordinated
to the metal atom. The molecular structures of 1 and
2 are shown in Figures 1 and 2, respectively.
1596 vw, 1559 vw, 1518 vw, 1461 s, 1419 w, 1386 w, 1287 s, 1149 vs, 1067 m,
1027 m, 854 w, 766 m, 743 w, 701 m, 555 w, 494 vw, 431 w cm±1
.
Structure determination
Single crystals of complex 1 and complex 2 were selected
and mounted on the goniometer of Rigaku R-AXIS RAPID
imaging plate diffractometer. Diffraction data were collected
at 123 k with graphite monochromated MoKa radiation
In both complexes, the metal atom co-ordination is
distorted octahedral with two CO groups cis to each
other but each trans to a nitrogen atom of dpphen.
The metal atom, two CO groups and dpphen are in
the equatorial plane. In the molecule of complex 1,
the W, N1, N2, C31, C32 atoms are coplanar to within
Ê
)k = 0.71073A) operating at 50 KV and 40 mA. Indexing was
performed from two oscillation images that were exposed
for 5 min. The detector swing angle was 5.00°. The crystal to
detector distance was 127.4 mm. Readout was performed in
the 0.100 mm pixel mode. Absorption corrections were
applied by correlation of symmetry-equivalent reflections
using the ABSOR program. Data reduction was performed
by SHELXS97 )Sheldrick, 1997). The structures were solved
by direct method and difference Fourier map using
SHELXS97 )Sheldrick, 1997) and refined on F2 by full-
matrix least-squares techniques using SHELXL97 )Shel-
drick, 1997).
2
Ê
0.16 A. The metal atom binds in an g fashion to the
C38±C39 and C50±C51 bonds of dibutylfumarate li-
gands. The two dbf ligands are trans to each other and
cis to CO groups. The two alkenes are almost
mutually orthogonal and each eclipses an N±W±CO
vector )average 164.86°) )Figure 1). In complex 2, the
Mo, N1, N2, C31, C32 atoms are coplanar to within
Ê
0.12A . The average N±Mo±CO angle is 168.5° )Fig-
The crystal data and structure refinement for complex 1
and 2 are given in Table 1. In the complex 1, the largest dif-
ure 2). There is little difference in bond angles and
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Z. Anorg. Allg. Chem. 2001, 627, 2481±2485

Synthesis and Structures of Bis)alkene) Complexes of Tungsten and Molybdenum
Fig. 1 Molecular structure of complex 1 showing 50% probability displacement ellipsoids.
Fig. 2 Molecular structure of complex 2 showing 50% probability displacement ellipsoids.
bond lengths between two complexes )Tables 2and 3).
tances )M = W, Mo) in [Mo)CO)4)dpphen)] [10],
[W)CO)2)phen))dbf)2] [12] or [W)C60))CO)2-
)phen))dbf)] [6] are 2.244 A, 2.202 A, 2.215 A, res-
Ê
The W±N distances )2.207 A, average) in 1 are shorter
Ê
Ê
Ê
Ê
than the Mo±N distances )2.239 A, average) in 2. The
Ê
average bond length of W±CO )1.999 A) in 1 is longer
pectively. The average M±CO bond lengths in
Ê
than that of Mo±CO )1.971 A) in 2, just as the average
Mo)CO)4)dpphen)],
[W)CO)2)phen))dbf)2],
or
Ê
Ê
Ê
bond length of C38±C39 and C50±C51 )1.442A in 1,
[W)C60))CO)2)phen))dbf)] are 1.964 A. 1.973 A
Ê
Ê
1.407 A in 2). In comparison, the average M±N dis-
1.992A , respectively. When one dbf was displaced by
Z. Anorg. Allg. Chem. 2001, 627, 2481±2485
2483

Xiangjin Xie, Xianglin Jin, Kaluo Tang
Ê
Table 2 Selected bond lengths/A and angles/° for complex 1
W)1)±C)32)
W)1)±C)31)
W)1)±N)2)
W)1)±N)1)
O)1)±C)31)
O)2)±C)32)
1.997)4)
2.001)4)
2.202)3)
2.211)3)
1.147)5)
1.146)5)
W)1)±C)50)
W)1)±C)39)
W)1)±C)38)
W)1)±C)51)
C)39)±C)38)
C)50)±C)51)
2.269)4)
2.276)4)
2.284)4)
2.285)4)
1.440)5)
1.443)5)
C)32)±W)1)±C)31)
C)32)±W)1)±N)2)
C)31)±W)1)±N)2)
C)32)±W)1)±N)1)
C)31)±W)1)±N)1)
N)2)±W)1)±N)1)
C)32)±W)1)±C)50)
C)50)±W)1)±C)39)
C)32)±W)1)±C)38)
C)31)±W)1)±C)38)
N)2)±W)1)±C)38)
N)1)±W)1)±C)38)
C)50)±W)1)±C)38)
C)39)±W)1)±C)38)
95.07)15)
165.36)14)
95.35)14)
97.41)13)
164.56)14)
74.19)11)
109.10)15)
163.55)14)
87.34)16)
72.28)16)
86.06)14)
117.29)14)
150.79)14)
36.82)13)
C)31)±W)1)±C)50)
N)2)±W)1)±C)50)
N)1)±W)1)±C)50)
C)32)±W)1)±C)39)
C)31)±W)1)±C)39)
N)2)±W)1)±C)39)
N)1)±W)1)±C)39)
C)32)±W)1)±C)51)
C)31)±W)1)±C)51)
N)2)±W)1)±C)51)
N)1)±W)1)±C)51)
C)50)±W)1)±C)51)
C)39)±W)1)±C)51)
C)38)±W)1)±C)51)
82.09)15)
82.54)13)
85.24)13)
82.54)15)
109.05)15)
84.35)13)
81.66)13)
72.41)16)
89.50)15)
117.92)14)
85.64)13)
36.95)13)
150.14)14)
151.61)14)
Fig. 3 Figure of the four regions of the complex 1 and 2.
Ê
Table 3 Selected bond lengths/A and angles/° for complex 2
Mo)1)±C)32)
Mo)1)±C)31)
Mo)1)±N)2)
Mo)1)±N)1)
O)1)±C)31)
O)2)±C)32)
1.966)9)
1.975)9)
2.233)7)
2.244)5)
1.161)10)
1.174)11)
Mo)1)±C)39)
Mo)1)±C)51)
Mo)1)±C)50)
Mo)1)±C)38)
C)38)±C)39)
C)50)±C)51)
2.249)9)
2.252)10)
2.266)8)
2.305)8)
1.421)13)
1.392)13)
Fig. 4 )left) Conformation of complex 1; )right) Conforma-
tion of complex 2.
chased, the resulting reaction solution was separated
by column chromatography over silca gel to two main
products [W)CO)2)phen))dbf)2] and [W)CO)2)phen)-
)dbf))dbm)]. It has been demonstrated that in the re-
action the ligand dbm was partly isomerized into dbf
that is more stable [12]. In this work, we used unpuri-
fied dibutyl maleate from the same source as before
to react with [W)CO)4)dpphen)] or [Mo)CO)4-
)dpphen)]. In the two reactions, we only obtained one
main product [W)CO)2)dpphen))dbf)2] or [Mo)CO)2-
)dpphen))dbf)2], which could be crystallized. The crys-
tals of [M)CO)2)dpphen))dbf))dbm)] have not been
obtained.
C)32)±Mo)1)±C)31)
C)32)±Mo)1)±N)2)
C)31)±Mo)1)±N)2)
C)32)±Mo)1)±N)1)
C)31)±Mo)1)±N)1)
N)2)±Mo)1)±N)1)
90.0)4)
166.1)3)
101.2)3)
96.2)3)
170.8)3)
73.8)2)
C)39)±Mo)1)±C)51) 151.5)4)
C)32)±Mo)1)±C)50) 85.3)3)
C)31)±Mo)1)±C)50) 106.6)3)
N)2)±Mo)1)±C)50)
N)1)±Mo)1)±C)50)
83.5)3)
80.8)3)
C)39)±Mo)1)±C)50) 160.0)3)
C)32)±Mo)1)±C)39) 109.3)3)
C)51)±Mo)1)±C)50)
C)32)±Mo)1)±C)38)
C)31)±Mo)1)±C)38)
N)2)±Mo)1)±C)38)
N)1)±Mo)1)±C)38)
C)39)±Mo)1)±C)38)
35.9)3)
73.0)3)
85.3)3)
115.8)3)
90.0)3)
36.3)3)
C)31)±Mo)1)±C)39)
N)2)±Mo)1)±C)39)
N)1)±Mo)1)±C)39)
C)32)±Mo)1)±C)51)
C)31)±Mo)1)±C)51)
N)2)±Mo)1)±C)51)
N)1)±Mo)1)±C)51)
87.4)3)
79.8)3)
84.1)3)
89.6)4)
71.0)3)
86.2)4)
115.8)3)
C)51)±Mo)1)±C)38) 150.7)4)
C)50)±Mo)1)±C)38) 155.5)3)
C60, the double bond length of the dbf ligand left
changed significantly )1.368 A in [W)C60))CO)2)phen)-
)dbf)]) compared to complex 1 )1.442A ).
The complexes 1 and 2 are good precursors for
further reaction. One or both dbf can be displaced by
C60. Further investigation is in process in our labora-
tory.
Ê
Ê
The two complexes have different conformation
which resultes from face selection of two dbf ligands
for coordination to metal atom [2]. If we view the
structure of 1 or 2 from the top of the equatorial
plane, the molecule is divided into four regions )I±IV)
by the two intersected N±M±CO vectors )Figure 3).
Detailed analysis of the structures reveals that in com-
plex 1 the two dbf ligands are bound to the W atom in
a fashion with all four ester groups )R) falling in re-
gions I and III as shown in Figure 4 )left). However,
in complex 2 the two dbf ligands are bound to the Mo
atom with four ester groups falling in regions I, II, III
and IV, respectively, as shown in Figure 4 )right).
Acknowledgments. We wish to express our gratitude for the
financial support of this work by National Natural Science
Foundation of China )Project No. 29873001 and 29733080).
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2484
Z. Anorg. Allg. Chem. 2001, 627, 2481±2485

Synthesis and Structures of Bis)alkene) Complexes of Tungsten and Molybdenum
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