Synthesis, fluxional behavior, and endo, exo-stereoisomers of allyl molybdenum complexes with O-ethyldithiocarbonate

Article abstract of DOI:10.1016/j.jorganchem.2008.07.025

The very air-sensitive η³-allyldicarbonylethoxydithiocarbonate molybdenum(II) compound [Mo(η³-C₃H₅)(CO)₂(S ₂COEt)(CH₃CN)] (1) are accessible by the reaction of [Mo(η³-C₃H₅)(CO)₂(Br)(CH ₃CN)₂] with KS₂COEt in methanol at ambient temperature. The rotational behavior of 1 in solution state was detected by variable-temperature ¹H NMR spectroscopy. The mechanism can be described as a trigonal twist, in which the rotation of the triangular face formed by the nitrogen ligand and the two sulfur atoms relative to the face formed by the allyl and the two carbonyl groups. The reactions of 1 with piperidine, 1-piperidinecarbodithioate, and bipyridine ligands give the replacement of the acetonitrile complex [Mo(η³-C₃H₅)(CO)₂(S ₂COEt)(C₅H₁₀NH)] (2), 16-electron complex [Mo(η³-C₃H₅)(CO)₂(S ₂CNC₅H₁₀)] (3), and η¹-O-ethyldithiocarbonate complex [Mo(η³-C₃H₅)(CO)₂(S ₂COEt)(bipy)] (4). Treatment of 1 with various diphos ligands form a mixtures of endo- and exo-complexes [Mo(η³-C₃H₅)(S₂COEt)(CO) (diphos)] (diphos: dppm = {bis(diphenylphosphino)methane} (endo-, exo-5); dppe = {1,2-bis(diphenylphosphino)ethane} (endo-, exo-6); dppa = {bis(diphenylphosphino)amine} (endo-, exo-8)) with ratios of 1:5, 1:2, and 4:5 according to the integration of ³¹P{¹H} NMR spectra, respectively. The orientations of endo and exo are defined for the open face of the allyl group and carbonyl group in the same direction in the former and opposite directions in the latter. The activation barriers of interconversion were determined to be 13.9 ± 0.2 kcal mol^-1 for (1) and 14.6 ± 0.2 kcal mol^-1 for (2). The X-ray crystal structures of [Mo(η³-C₃H₅)(CO)₂(S ₂COEt)(CH₃CN)] (1b), [Mo(η³-C₃H₅)(S₂COEt)(CO) (dppm)] (exo-5), and [Mo(η³-C₃H₅)(S₂COEt)(CO) (dppa)] (endo-, exo-8) are employed to elucidate the coordination mode of the dithiocarbonate ligand and the endo-, exo-orientations. One crystallographically independent molecule of 8 is contained in the cell, in which the open face of the allyl group is disordered toward two directions, i.e. endo and exo. In addition, the endo:exo ratio in the solid state is 62:38.

Full text of DOI:10.1016/j.jorganchem.2008.07.025

Journal of Organometallic Chemistry 693 (2008) 3303–3311
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis, fluxional behavior, and endo, exo-stereoisomers of allyl
molybdenum complexes with O-ethyldithiocarbonate, EtOCSꢀ2 , containing ligand:
Crystal structures of [Mo(CH3CN)(g
3-C3H5)(CO)2(S2COEt)],
exo-[Mo(dppm)(g
3-C3H5)(CO)(S2COEt)], and endo-,
exo-[Mo(dppa)(
g
3-C3H5)(CO)(S2COEt)]
b
Kuang-Hway Yih a, , Gene-Hsiang Lee
*
a Department of Applied Cosmetology, Hungkuang University, No. 34, Chung Chie Road, Shalu, Taichung Hsien, Taiwan 433, ROC
b Instrumentation Center, College of Science, National Taiwan University, Taiwan, ROC
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 14 May 2008
Received in revised form 21 July 2008
Accepted 22 July 2008
Available online 29 July 2008
The very air-sensitive
C3H5)(CO)2(S2COEt)(CH3CN)] (1) are accessible by the reaction of [Mo(
g
3-allyldicarbonylethoxydithiocarbonate molybdenum(II) compound [Mo(g3
3-C3H5)(CO)2(Br)(CH3CN)2] with
-
g
KS2COEt in methanol at ambient temperature. The rotational behavior of 1 in solution state was detected
by variable-temperature 1H NMR spectroscopy. The mechanism can be described as a trigonal twist, in
which the rotation of the triangular face formed by the nitrogen ligand and the two sulfur atoms relative
to the face formed by the allyl and the two carbonyl groups. The reactions of 1 with piperidine, 1-pip-
eridinecarbodithioate, and bipyridine ligands give the replacement of the acetonitrile complex
Keywords:
endo
[Mo(
and
ious diphos ligands form a mixtures of endo- and exo-complexes [Mo(
g
g
3-C3H5)(CO)2(S2COEt)(C5H10NH)] (2), 16-electron complex [Mo(
1-O-ethyldithiocarbonate complex [Mo( 3-C3H5)(CO)2(S2COEt)(bipy)] (4). Treatment of 1 with var-
3-C3H5)(S2COEt)(CO)(diphos)]
g
3-C3H5)(CO)2(S2CNC5H10)] (3),
exo-Stereoisomers
Allyl
Molybdenum
O-Ethyldithiocarbonate
Crystal structures
g
g
(diphos: dppm = {bis(diphenylphosphino)methane} (endo-, exo-5); dppe = {1,2-bis(diphenylphos-
phino)ethane} (endo-, exo-6); dppa = {bis(diphenylphosphino)amine} (endo-, exo-8)) with ratios of 1:5,
1:2, and 4:5 according to the integration of 31P{1H} NMR spectra, respectively. The orientations of endo
and exo are defined for the open face of the allyl group and carbonyl group in the same direction in the
former and opposite directions in the latter. The activation barriers of interconversion were determined
to be 13.9 0.2 kcal molꢀ1 for (1) and 14.6 0.2 kcal molꢀ1 for (2). The X-ray crystal structures of
[Mo(g g -
3-C3H5)(CO)2(S2COEt)(CH3CN)] (1b), [Mo( 3-C3H5)(S2COEt)(CO)(dppm)] (exo-5), and [Mo(g3
C3H5)(S2COEt)(CO)(dppa)] (endo-, exo-8) are employed to elucidate the coordination mode of the dithio-
carbonate ligand and the endo-, exo-orientations. One crystallographically independent molecule of 8 is
contained in the cell, in which the open face of the allyl group is disordered toward two directions, i.e.
endo and exo. In addition, the endo:exo ratio in the solid state is 62:38.
Ó 2008 Elsevier B.V. All rights reserved.
1. Introduction
and pyridyl-exchange mechanism have been reported when the L
ligands were replacement by pyridylphosphane or their oxides li-
The X-ray crystallography [1] and fluxionality [2] of complexes
containing the [Mo(
3-allyl)(CO)2( 2-L)X] (L: pyrazolylborate, b-
gands. Notably, the rotational behavior and stereoisomers of com-
plexes with the type [Mo(
rarely.
g
g
g
3-allyl)(CO)(PP)(SS)] have been studied
diketonate, dithiocarbamate, X: neutral monodentate ligand; L: di-
phos, pyridylphosphane, X: halide) type have been well studied as
an intramolecular trigonal twist. The most important result is that,
We have previously studied the first endo-, exo- complexes
[Mo(
3-C3H5)(CO)(dppm){S2P(OEt)2}] from 31P{1H} NMR spectra
[5], fluxional behavior and clear crystal structures of two confor-
g
the coordinated
g
3-allyl group showed a conformation that the
open face of the allyl group and the two carbonyl groups are to-
ward in the same direction. An electronic stabilization [3] for this
particular orientation is indicated. A pivoted double switch [4]
mations of complexes including the [Mo(
type (PP: diphos; SS: dithiocarbamate) [6].
g
3-C3H5)(PP)(CO)(SS)]
In this work we continuously investigate the syntheses, flux-
ional behavior and endo-, exo- conformational crystal structures
of O-ethyldithiocarbonate Mo(II) complexes. The crystallographic
evidences for endo- and exo-allyl ligand are presented.
* Corresponding author. Tel.: +886 4 26318652x1200; fax: +886 4 26310579.
E-mail address: khyih@sunrise.hk.edu.tw (K.-H. Yih).
0022-328X/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2008.07.025

3304
K.-H. Yih, G.-H. Lee / Journal of Organometallic Chemistry 693 (2008) 3303–3311
the clean and high yield formation of the 16-electron dithiocarba-
mate complex [Mo(
3-C3H5)(CO)2(S2CNC5H10)] (3) with releasing
2. Results and discussion
g
the EtOC(S)SH ligand. Complex 3 also can be produced from the
reaction of 2 with carbon disulfide. The CS2 insertion reaction into
the M–N bond (M = Cr, Mo, W) promoted by the abstraction of a
proton on the nitrogen atom of the piperidine ligand by nBuLi to
2.1. Syntheses
We have reported a convenient way to prepare the dithio allyl
complexes with the type [Mo(
[7]; S2CNEt2; S2P(OEt)2, CH3CN [8]) from the reaction of complex
[Mo(
3-C3H5)(CO)2(CH3CN)2(Br)] and the dithio ligands in acetoni-
trile at room temperature. Thus, treatment of [Mo(g3
C3H5)(CO)2(CH3CN)2(Br)] with KS2COEt in methanol at ambient
temperature obtained complex [Mo(CH3CN)(
3-C3H5)(CO)2(S2-
g
3-C3H5)(CO)2(L)] (L = S2CNC4H8
form the
g
2-dithiocarbamate ligand have been reported by us
[9]. From the reaction, it is believed to be induced by the stronger
g
ꢀ
p
-donor ability of C5H10NCS2 ligand, by insertion of CS2 into the
-
Mo–N bond of 2 to give dithiocarbamate complex 3 with releasing
the EtOC(S)SH ligand. The yellow-orange crystalline product 3 was
slightly air-sensitive, insoluble in CH2Cl2, CH3CN and only slightly
soluble in DMSO. Treatment of 1 with bipyridine produced the
g
COEt)] (1) with 90% isolated yield (Scheme 1). Compound 1 is a
very air-sensitive red solid which is readily soluble in organic sol-
vents such as dichloromethane, toluene and acetonitrile but insol-
uble in saturated hydrocarbons. The yellow air-sensitive complex
red air-stable complex [Mo(g
3-C3H5)(bipy)(CO)2(S2COEt)] (4) with
98% isolated yield. Compound 4 also can be obtained from the reac-
tion of 2 with bipy in CH2Cl2 at room temperature.
[Mo(g
3-C3H5)(CO)2(S2COEt)(C5H10NH)] (2) was prepared by the
Treatment of 1 with various diphos ligands in refluxing acetoni-
trile yield mixtures of the air-sensitive and yellow-orange com-
reaction of 1 with C5H10NH at room temperature with 87% isolated
yield. Compound 2 is soluble in polar solvent, and slightly soluble
in n-hexane. The reaction of 1 and C5H10NC(S)SH in CH2Cl2 lead to
plexes [Mo(
g
3-C3H5)(CO)(diphos)(S2COEt)] (diphos: dppm, endo,
bipy
O
S
S
C
EtO C
O
Mo
NH
N
bipy
C
C
C5H10NH
C
O
Mo
S
N
O
2a
4
S
C
EtO
trigonal
twist
trigonal
twist
O
S
S
C
O
C
H3CCN
S
EtO C
Mo
Mo
O
C
C
NH
O
C
O
Mo
S
N
S
C
S
C
C
O
C
C
EtO
H3
2b
1b
EtO
1a
CS2
O
C5H10NCS2H
EtOCS2K
H3CCN
H3CCN
C
O
S
S
C
Mo
Br
N
C
Mo
C
O
C
O
3
Scheme 1.
O
O
dppm
dppe
S
S
C
C
EtO C
EtO C
EtO C
+
Mo
Mo
S
Ph P
PPh
S
Ph P
PPh
2
2
2
2
O
C
exo-5
S
S
endo-5
1:5
EtO C
+
Mo
O
C
trigonal
twist
O
O
C
S
S
O
O
PPh
S
S
S
S
C
2
H CCN
3
C
C
EtO C
Mo
Mo
EtO C
Mo
+
Mo
Ph P
C
2
C
S
PPh
PPh
2
O
2
O
S
N
C
C
S
Ph P
Ph P
C
2
2
Mo
O
O
C
C
OEt
EtO
S
exo-6
C
endo-6
1b
H
3
1:2
1a
7
O
dppa
S
S
O
C
S
C
EtO C
+
Mo
EtO C
Mo
PPh
2
S
Ph P
PPh
2
Ph P
2
N
H
2
N
H
1/2 dppe
CH Cl
exo-8
4:5
endo-8
2
Scheme 2.

K.-H. Yih, G.-H. Lee / Journal of Organometallic Chemistry 693 (2008) 3303–3311
3305
exo-5; dppe, endo, exo-6; dppa, endo, exo-8) with endo:exo ratios of
4
4'
5
1:5, 1:2, and 4:5 and ca. 88%, 85% and 92% isolated yield, respec-
tively (Scheme 2). The orientations of endo and exo are defined
by the open face of the allyl group and carbonyl group being in
the same direction in the former and opposite direction on the
6
5'
6'
3'
O
S
C
O
trigonal
twist
H3CCN
C
O C
CH3CH2
Mo
Mo
S
S
C
O
1
2
C
S
C
O
N
C
latter [6]. Except endo, exo-6,
C3H5)(S2COEt)(CO)]2( -dppe) (7) was obtained in the reaction of
a -
dimetal complex [Mo(g3
C
CH3CH2O
1' 2'
H3
3
l
1b
1 and dppe. The CH2Cl2 solution of dppe was slowly added into a
CH3CN solution of 1 with ratios of 1:2, complex 7 was formed as
the sole product with 96% isolated yield.
1a
These compounds 5–8 are soluble in dichloromethane, slightly
soluble in acetonitrile and insoluble in diethyl ether and n-hexane.
The compounds 1, 2, 4–8 were already of good purity, but analyt-
ically pure samples could be obtained by slow n-hexane diffusion
into a dichloromethane solution at +4 °C. All characterization data
are consistent with the proposed constitution.
2.2. IR and MS spectroscopy
The presence of one or two carbonyl groups for all complexes in
this work is clearly reflected in the IR spectra. In KBr, two terminal
carbonyl-stretching bands were found in equal intensity in 1–4
and 7; this observation indicates that the two carbonyls are mutu-
ally cis. Although both isomers are known to be present in different
ratios, only one terminal carbonyl-stretching band was found in 5,
6, and 8. Because of limited solubility, all IR spectra needed to be
recorded in CH2Cl2, and therefore any small difference might be
obscured by the natural line-broadening in this solvent. In the
FAB mass spectra, base peaks with the typical Mo isotope distribu-
tion are in agreement with the [M+] molecular ion for complexes
1–7 and [M+ꢀCO] for complex 8.
2.3. NMR spectroscopy
From an AM2X2 pattern of the allyl group in the 1H NMR spectra
and one equivalent resonance of the terminal carbon of the allyl
group and one resonance of carbonyl group in the 13C{1H} NMR
spectra, it looks as if 1 has the geometry with a mirror plane
through the center carbon of allyl group, Mo, O atom of the dithio-
carbamate ligand and CH3CN; i.e., the bidentate ligand and the two
carbonyls lie in a horizontal plane, whereas the allyl group and the
CH3CN ligand lie in trans positions above and below the plane,
respectively (Fig. 1). Because the mentioned structure is incompat-
ible with the report by Miguel [10], the variable-temperature 1H
NMR experiments were undertaken. By variable-temperature 1H
NMR spectra, complex 1 in solution exhibits fluxional behavior,
and the dynamic process has been examined. As depicted in Fig.
1, an AM2X2 pattern is observed for the allyl protons, and a single
resonance for the methyl protons of the acetonitrile group. How-
ever, on cooling (CD3)2CO solutions of 1, the proton signals initially
broaden and below 296 K the methyl resonance of CH3CN and the
syn- and anti-proton signals of the allyl moiety each begin to sep-
arate into two components. Below 223 K, 1H NMR data are shown
another set of peaks (ABCDX), which is in according with the solid-
state geometry of 1b. The mechanism can be described as a trigo-
nal twist, in which the rotation of the triangular face formed by the
CH3CN and the two sulfur atoms relative to the face formed by the
allyl and the two carbonyl groups. The rotation mechanism has
been previously described for the trigonal twist behavior of
Fig. 1. Variable-temperature 1H NMR spectra of 1 in acetone-d6.
and is smaller than that of complex [Mo(pd)(
(14.3 kcal molꢀ1) [10].
g
3-C3H5)(CO)2(py)]
Similar spectroscopic phenomena of the carbonyl group and al-
lyl moiety in IR and 1H, 13C{1H} NMR spectra guide us to believe
that complex 2 contains the same solution rotational behavior as
1. To confirm the result, the variable-temperature 1H NMR exper-
iments of 2 were carried out.
D
Gà value calculated from line-shape
analysis of the variable-temperature 1H NMR is 14.6 0.2
kcal molꢀ1 for 2. The large activation energy of 2 compared with
1 is due to the more steric hindrance of the C5H10NH ligand than
CH3CN. In fact, this value is essentially independent of the nature
of dithiocarbonato ligand, increases with increase in the size of
the neutral monodentate ligand, and greater for the substitute allyl
than for the allyl complexes. Notably, the dissociation mechanism
[10] of the C5H10NH ligand was neglected because increasing the
temperature to 330 K resolved no signals of free C5H10NH.
The 1H and 13C{1H} NMR spectral data of 3 are the same as those
of the known 16 electron complex [Mo(g
3-C3H5)(CO)2-
[Mo(pd)(
[12]. Line-shaped analysis of the variable-temperature has been
calculated from 1H NMR spectra of
yields value of
13.9 0.2 kcal molꢀ1 for Gà. Compared with other trigonal twist
complexes, the activation energy of 1 is larger than those of
complex Mo( [13] and
3-C3H5)(CO)2(dppm)I (11.2 kcal molꢀ1
[Mo( [8]
3-C3H5)(CO)2{(S2P(OEt)2)}(CH3CN)] (11.6 kcal molꢀ1
g
3-C3H5)(CO)2(py)] [11] and other related complexes
(S2CNC5H10)] [8]. From an AM2X2 pattern of the allyl group in the
1H NMR spectra and one equivalent resonance of the terminal car-
bon of the allyl group, four sets resonance of bipyridine group, and
one resonance of carbonyl group in the 13C{1H} NMR spectra, the
geometry of 4 was shown a mirror plane through the center carbon
of allyl group, Mo, and coordinative S atom of the dithiocarbonato
ligand; i.e., the bipyridine ligand and the two carbonyls lie in a
1
a
D
g
)
g
)

3306
K.-H. Yih, G.-H. Lee / Journal of Organometallic Chemistry 693 (2008) 3303–3311
O
O
C
S
S
S
S
C
EtO C
EtO C
+
Mo
Mo
PPh2
PPh2
Ph2P
Ph2P
endo-5
1:5
exo-5
4
5
6
O
S
S
C
CH3CH2O C
Mo
PPh2
1
2
Ph2P
3
S
S
CO
PPh2
3'
+
exo-5
C
EtO
Mo
Ph2P
endo-5
1:5
Fig. 2. (a) Homonuclear shift-correlated 2-D NMR spectrum for 31P nuclei with 1H decoupling for the mixtures endo-5 and exo-5 in acetone-d6. (b) Homonuclear shift-
correlated 2-D NMR spectrum of endo- and exo-5 (1:5) in CDCl3.
Table 1
Crystal data and refinement details for complexes 1b, exo-5, and endo, exo-8
1b
exo-5
endo, exo-8
Chemical formula
Formula weight
Crystal system
Space group
a (Å)
C
10H13NO3S2Mo
C32H32O2P2S2Mo
670.58
Monoclinic
P21
10.2519(2)
15.8528(2)
11.7698(2)
90
C31H31NO2P2S2Mo
671.57
Monoclinic
P21/n
12.7835(2)
14.5988(2)
16.4824(2)
90
355.27
Monoclinic
P21/c
7.2178(1)
12.2401(2)
16.1978(3)
90
b (Å)
c (Å)
a
(°)
b (°)
100.394(1)
90
1407.54(4)
4
1.677
1.223
103.0812(9)
90
1510.61(5)
2
1.474
0.707
94.2263(7)
90
3067.64(7)
4
1.454
0.697
c
(°)
V (Å3)
Z
qcalcd (g cmꢀ3
)
l
(Mo K
a
) (mmꢀ1
)
k (Å)
T (K)
0.71073
150(1)
2.10–27.50
3231
0.71073
150(1)
1.78–27.50
6668
0.71073
150(1)
2.12–27.50
7043
h Range (°)
Independent reflections
Number of variables
156
0.017
0.044
1.057
353
0.036
0.076
1.039
372
0.035
0.078
1.045
Ra
Rw
Sb
P
P
a
R = ||Fo| ꢀ |Fc||/ |Fo|.
P
b
Quality-of-fit = [ w(|Fo| ꢀ |Fc|)2/(Nobserved ꢀ Nparameters)]1/2
.

K.-H. Yih, G.-H. Lee / Journal of Organometallic Chemistry 693 (2008) 3303–3311
3307
Table 2
horizontal plane, whereas the allyl group and the dithiocarbonato
Selected interatomic distances (Å) and angles (°) for 1b, exo-5, and endo, exo-8
ligand lie in trans positions above and below the plane, respec-
tively (Scheme 1). Variable temperature (183–298 K) 1H NMR
experiments were used to confirm no intramolecular trigonal twist
behavior in complex 4 due to the steric hindrance of bipyridine and
dithiocarbonato ligands.
Bond lengths
Bond angles
Compound 1b
Mo–C(1)
Mo–C(2)
Mo–C(3)
Mo–C(4)
Mo–C(5)
Mo–N(1)
Mo–S(1)
1.9518(14)
1.9595(15)
2.324(2)
2.2214(15)
2.3382(15)
2.2394(12)
2.6167(4)
2.5350(4)
1.415(2)
C(1)–Mo–C(2)
C(1)–Mo–N(1)
C(2)–Mo–S(2)
C(4)–Mo–S(2)
C(1)–Mo–C(4)
C(2)–Mo–S(1)
S(1)–Mo–S(2)
C(3)–C(4)–C(5)
S(1)–C(6)–S(2)
N(1)–C(9)–C(10)
78.48(6)
168.14(5)
94.26(5)
157.88(4)
105.25(6)
162.93(5)
68.870(11)
115.90(14)
118.41(8)
179.6(2)
The 1H and 13C{1H} NMR spectral data for complex [Mo(g3
-
C3H5)(S2COEt)(CO)(dppm)] (5) are obtained only for the major
products, because of the low ratio and no isolation of the minor
products. Interestingly, their room temperature 1H NMR spectra
(Fig. 2) exhibit five sets of resonances for the allyl moiety typical
Mo–S(2)
C(3)–C(4)
C(4)–C(5)
Compound exo-5
Mo–C(1)
Mo–C(3)
Mo–C(4)
Mo–C(2)
Mo–P(2)
Mo–P(1)
Mo–S(1)
of the ABCDX spin patterns of unsymmetrical
bonate metal complexes.
g
3-allyl dithiocar-
1.412(2)
In the 1H NMR spectrum of exo-5, the methylene protons of the
dppm ligand and allyl protons exhibit seven equally intense reso-
nances at d 3.82, 4.22 and at d 2.24, 2.55 (Hanti), d 2.42, 4.01 (Hsyn),
d 4.91 (Hcenter), respectively. The corresponding 13C{1H} NMR sig-
nals are at d 41.5, and d 54.7, 68.9, 100.6. In the 13C{1H} NMR spec-
trum of exo-5, two resonances appear in the carbonyl region. One
resonance at d 227.1 is attributed to the carbonyl group and the
resonance at d 222.5 is assigned to the carbon atom of the CS2 of
the EtOCS2 ligand. The other 1H and 13C{1H} NMR spectra of com-
plexes 6 and 8 are similar to that of 5.
1.912(3)
2.328(4)
2.341(4)
2.357(4)
2.4490(9)
2.4697(9)
2.5157(7)
2.6102(9)
1.679(4)
1.694(4)
1.179(4)
1.371(7)
1.365(7)
C(3)–Mo–P(1)
P(2)–Mo–P(1)
C(1)–Mo–S(1)
P(2)–Mo–S(1)
P(1)–Mo–S(1)
C(1)–Mo–S(2)
C(2)–Mo–S(2)
P(2)–Mo–S(2)
S(1)–Mo–S(2)
O(1)–C(1)–Mo
C(4)–C(3)–C(2)
163.84(14)
67.44(3)
99.79(10)
141.77(4)
77.83(3
167.89(10)
88.91(11)
94.75(3)
68.53(3)
179.0(3)
121.5(5)
Mo–S(2)
S(1)–C(5)
S(2)–C(5)
O(1)–C(1)
C(2)–C(3)
C(3)–C(4)
Compared to the 31P{1H} NMR spectra and the structures of the
complexes exo-5, and endo-, exo-8, it can be concluded that: (1) the
dithiocarbonate ligand improves the formation of exo-products; (2)
exo-complexes show larger JP–P coupling constants than those of
endo-complexes; (3) the resonances of dppm, dppe and dppa com-
plexes appear in relative up-field for the exo-orientation.
Compound endo, exo-8
1.915(3)
Mo–C(1)
Mo–C(30)
Mo–C(3)
Mo–C(40)
Mo–C(2)
Mo–C(4)
Mo–P(1)
Mo–P(2)
Mo–S(1)
Mo–S(2)
S(1)–C(5)
S(2)–C(5)
P(1)–N(1)
P(2)–N(1)
O(1–)C(1)
C(2)–C(30)
C(2)–C(3)
C(3)–C(4)
C(30)–C(40)
C(1)–Mo–C(30)
C(1)–Mo–C(3)
C(30)–Mo–C(4)
C(3)–Mo–C(4)
C(1)–Mo–P(1)
C(40)–Mo–C(2)
C(2)–Mo–C(4)
C(40)–Mo–P(2)
C(4)–Mo–P(2)
P(1)–Mo–P(2)
S(1)–Mo–S(2)
N(1)–P(1)–Mo
N(1)–P(2)–Mo
P(2)–N(1)–P(1)
O(1)–C(1)–Mo
C(4)–C(3)–C(2)
C(40)–C(3)–C(2)
C(30)–C(40)–Mo
S(2)–C(5)–S(1)
81.6(5)
102.2(3)
27.8(3)
34.1(3)
85.07(9)
62.0(3)
61.96(19)
156.0(3)
153.67(19)
65.57(2)
68.04(2)
96.09(8)
94.80(8)
103.53(12)
179.0(3)
121.1(9)
123.2(17)
68.7(5)
2.217(8)
2.306(5)
2.315(9)
2.318(3)
2.401(5)
2.4212(7)
2.4662(7)
2.5156(8)
2.6053(7)
1.704(3)
1.676(3)
1.691(2)
1.678(2)
1.181(4)
1.360(14)
1.408(8)
1.382(13)
1.35(2)
A rearrangement involving a
p
–r
–p
[14] process or allyl rota-
tion or intramolecular trigonal twist rearrangement have been re-
ported in [Mo(
g
3-allyl)] type complexes. In the range of 298–
348 K, the variable-temperature 1H and 31P{1H} NMR experiments
were undertaken to investigate the interconversion of complexes
endo, exo-5 and endo, exo-8. Because these complexes were decom-
posed in CDCl3 at higher temperatures and poorly soluble in
CD3CN, these measurements were not pursued further.
2.4. X-ray single-crystal structures of 1b, endo-5, and endo-, exo-8
115.96(16)
For satisfactory structural characterization, we performed X-ray
diffraction studies of 1b, endo-5, and endo-, exo-8 to elucidate the
unequivalent allyl group and endo- and exo-conformers at 150 K.
Crystal data and refinement details and selected interatomic dis-
tances (Å) and angles (°) of complexes 1b, endo-5, and endo-, exo-
8 are listed in Tables 1 and 2, respectively. ORTEP plots of the three
complexes are shown in Figs. 3–5.
An ORTEP plot of 1b is shown in Fig. 3. The coordination geom-
etry around the molybdenum atom is approximately an octahe-
dron with the two O-ethyldithiocarbonato sulfur atoms,
acetonitrile, two carbonyls and the allyl group occupying the six
coordination sites. The structure confirms an asymmetric allyl
group. One of the sulfur atoms of dithiocarbonato is trans to the al-
lyl: S(2)–Mo–C(4), 157.88(4)°, while the other is trans to one car-
bonyl: S(1)–Mo–C(2), 162.93(5)°. The remaining carbonyl is trans
to the nitrogen atom of the acetonitrile: C(1)–Mo–N(1),
168.14(5)°. The S–Mo–S angle of 68.87(11)° in 1b is similar to
68.53(3)° in 5 and 68.04(2)° in 8 within the experimental errors.
The Mo–C(3), C(4) and C(5) bond distances are 2.324(2), 2.221(2)
and 2.332(2) Å, respectively. The Mo–S(2) distance of 2.5350(4) Å
(trans to allyl) is clearly shorter than Mo–S(1) of 2.6167(4) Å (trans
to CO) because of the higher trans influence induced by the CO
group more than the allyl group.
From Figs. 4 and 5, the open face of the allyl group is oriented
towards the carbonyl group in endo-8 and in the opposite direc-
tions in exo-5 and exo-8. In the three structures, the coordination
Fig. 3. An ORTEP drawing with 50% thermal ellipsoids and atom-numbering
scheme for the complex [Mo(CH3CN)(
3-C3H5)(CO)2( 2-S2COEt)] (1b).
g
g

3308
K.-H. Yih, G.-H. Lee / Journal of Organometallic Chemistry 693 (2008) 3303–3311
Fig. 4. An ORTEP drawing with 50% thermal ellipsoids and atom-numbering scheme for the complex [Mo(g g g
2-dppm)( 3-C3H5)(CO)( 2-S2COEt)] (exo-5).
geometry around the molybdenum atom is approximately an octa-
hedron with the two sulfur atoms of the dithiocarbonato ligand,
two phosphorus atoms of the diphos ligand, one carbonyl and
the allyl group occupying the six coordination sites. It is confirmed
that the allyl groups in three structures are asymmetric. One of
the sulfur atoms of dithiocarbonato ligand is trans to the diphos:
S–Mo–P, 141.77(4)–144.40(3)°, while the other is trans to car-
bonyl: S–Mo–C, 167.89(10)–169.39(9)°. The S(1)–Mo–S(2) angles
68.04(2)–68.53(3)° in dithiocarbonate complexes are similar to
68.071(17)–68.459(17)° in dithiocarbamate complexes and smal-
ler than 75.27(57)–76.02(5)° in dithiophosphate complexes [6] be-
cause of the different PS2 and CS2 hybridization of the P and C
atoms. An examination of the S(1)–C(5)–S(2) bond distances and
angles shows a geometrical environment characteristic of a sp2
hybridization of the carbon atom. In addition, the S(1)–C(5)–S(2)
angles in the range of 115.96(16)–117.72(19)°, are significantly dif-
ferent from the S(1)–P–S(2) angles which are in the range of
109.67(10)–111.07(10)°.
The short C–OEt bond length 1.321(2) –1.341(4) Å of the dithio-
carbonate complexes 1b endo-5, and endo-, exo-8 indicate a consid-
erable partial double bond character (C–O: 1.43, C@O: 1.20, C„O:
1.128 Å). The Mo–S(1) distance (trans to phosphorus) is clearly
shorter than Mo–S(2) (trans to CO) because of the higher trans
influence induced by the CO group more than the phosphine group.
Similarly, the Mo–P distance (trans to sulfur) is slightly shorter
than Mo–P (trans to allyl) because of the higher trans influence in-
duced by the allyl group more than the dithiocarbonato group. The
Mo–S (2.5156(8)–2.6167(4) Å) and Mo-allyl (2.217(8)–2.401(5) Å)
bond distances are consistent with the values reported for MoII–S
and numerous Mo-allyl systems [1a,2,15]. The bond distances
and intercarbon angle of allyl group in complexes 1b, endo-5, and
endo-, exo-8 (1.412(2)–1.415(2) Å, 1.365(7)–1.371(7) Å, 1.35(2)–
1.408(8) Å and 115.90(14)–123.2(17)°) are insignificantly different
and close to the region of related MoII-allylic compounds (1.31–
1.42 Å, 115–125°) [13]. The Mo–P bond lengths are in the region
of 2.4212(7)–2.4697(9) Å, and appear to be normal. The carbonyl
ligand is essentially linear with region of 174.98(13)–179.0(3)°.
The values for the Mo–CO angles are similar to those found for
other terminal carbonyls contained in Mo systems. The Mo–CO
(1.912(3)–1.9595(15) Å) and C–O distances are both within the
range of values reported for other molybdenum carbonyl com-
plexes [4,5,8,15].
X-ray structure determination of 8 at 150 K reveals the presence
of two crystallographically inequivalent molecules in the nuit cell,
Fig. 5. ORTEP drawing with 30% thermal ellipsoids and atom-numbering scheme
for the complex [Mo(g g g
2-dppa)( 3-C3H5)(CO)( 2-S2COEt)] (endo, exo-8).

K.-H. Yih, G.-H. Lee / Journal of Organometallic Chemistry 693 (2008) 3303–3311
3309
which differ mainly by the orientation of the allyl group with re-
spect to the carbonyl group. The two molecules endo-8 and exo-8
with ratio of 1:1 were depicted in Fig. 5 together with the labeling
scheme. The ratio of endo-8:exo-8 is 62:38 in solid state and with
4:5 ratio in solution state by integrating from 31P{1H} NMR spectra.
To our knowledge, the concomitant presence of two different allyl
orientation isomers of this kind in one unit cell has been rarely
noted [16].
tration (G4), washed with n-hexane (2 ꢁ 10 ml) and subsequently
drying under vacuum yielding a mixture of [Mo(CH3CN)(g3
-
C3H5)(CO)2(S2COEt)] (1) (0.32 g, 90%) as a red microcrystalline so-
lid. Further purification was accomplished by recrystallization
from 1/10 CH2Cl2/n-hexane. Spectroscopic data of 1 are as follows.
IR (KBr, t
CO/cmꢀ1): 1935(vs), 1860(vs). 1H NMR (500 MHz, C3D6O,
298 K): d 1.33 (t, 3H, OCH2CH3, JH–H = 11.6 Hz), 1.35 (m, 2H, Hanti),
2.05 (br, 3H, CH3CN), 3.29 (d, 2H, Hsyn, JH–H = 10.8 Hz), 4.22 (m, 1H,
Hcentre), 4.46 (q, 2H, OCH2, JH–H = 11.6 Hz). 13C{1H} NMR
(125 MHz, C3D6O, 298 K): d 0.9 (s, CH3CN), 13.1 (s, OCH2CH3),
56.4 (br, CH2@CH), 67.7 (s, OCH2), 73.2 (br, CH2@CH), 116.2 (s,
CH3CN), 227.2 (s, CO). Anal. Calc. for C10H13NO3S2Mo: C, 26.01; H,
2.84; N, 3.03. Found: C, 26.25; H, 2.91; N, 3.02%.
3. Concluding remarks
The trigonal twist fluxional behavior of the O-ethyldithiocar-
bonate Mo complexes 1 and 2 were confirmed and the activation
barriers of interconversion were determined to be 13.9
0.2 kcal molꢀ1 and 14.6 0.2 kcal molꢀ1, respectively. We employ
three different diphos ligands to investigate the dependence of
the ratio of the endo- and exo-conformer. The O-ethyldithiocarbo-
nato ligand improves the formation of exo-products in the three
diphos ligands, whereas it is different to the previous report that
the dithiophosphate ligand improves the formation of endo-prod-
ucts and the dithiocarbamate ligands improve the formation of
endo-products in dppe ligand and of exo-products in dppm ligand.
The exo-complexes show larger JP–P coupling constants than endo-
complexes and the resonances of dppm, dppe and dppa complexes
appear in relative up-field for the exo-orientation. These results are
identical with the dithiocarbamate and dithiophosphate ligands.
4.3. Preparation of 2
A solution of [Mo(CH3CN)(g
3-C3H5)(CO)2(S2COEt)] (1) (0.355 g,
1.0 mmol) in CH2Cl2 (20 ml) was treated with C5H10NH (0.1 ml,
1.2 mmol) at ambient temperature. Instantly, the reaction mixture
turned to yellow. After 10 min of stirring, the solution was dried in
vacuo. Subsequently, n-hexane (40 ml) was added to the solution
and a yellow precipitate was formed. The precipitate was collected
by filtration (G4) and dried in vacuo to yield 0.35 g (87%) of
[Mo(
g
3-C3H5)(CO)2(S2COEt)(C5H10NH)] (2). IR (KBr, cmꢀ1):
t(CO)
1929(vs), 1836(vs) cmꢀ1
.
1H NMR (500 MHz, CDCl3, 298 K): d
1.12 (d, 2H, Hanti, JH–H = 9.4 Hz), 1.33 (t, 6H, OCH2CH3, JH–H
7.4 Hz), 1.77 (m, 6H, NCH2CH2CH2), 3.25 (d, 2H, Hsyn, JH–H
=
=
The X-ray crystal structures of [Mo(
COEt)(CH3CN)] (1), [Mo(
3-C3H5)(S2COEt)(CO)(dppm)] (exo-5),
and [Mo(
3-C3H5)(S2COEt)(CO)(dppa)] (endo-, exo-8) are em-
g
3-C3H5)(CO)2(S2-
6.6 Hz), 3.53 (m, 4H, NCH2), 3.90 (m, 1H, Ccentre), 4.08 (q, 4H,
OCH2, JH–H = 7.4 Hz). 13C{1H} NMR (125 MHz, CDCl3, 298 K): d
16.0 (s, OCH2CH3), 25.6 (s, NCH2CH2CH2), 49.9 (s, NCH2CH2), 56.0
(s, CH@CH2), 63.0 (s, NCH2), 64.0 (s, OCH2), 72.0 (s, CH2@CH),
195.1 (s, OCS2), 219.6 (s, CO). MS (FAB, NBA): m/z 399 (M+). Anal.
Calc. for C13H21NO3S2Mo: C, 39.09; H, 5.30; N, 3.51. Found: C,
39.25; H, 5.61; N, 3.42%.
g
g
ployed to elucidate the coordination mode of the O-ethyldithiocar-
bonato ligand and the endo-, exo-orientations.
4. Experimental
4.1. General procedures
4.4. Preparation of 3
All manipulations were performed under nitrogen using vac-
uum-line, drybox, and standard Schlenk techniques. NMR spectra
were recorded on a Bruker AM-200, or on an AM-500 WB FT-
NMR spectrometer and are reported in units of parts per million
with residual protons in the solvent as an internal standard (CDCl3,
d 7.24; CD3CN, d 1.93; C2D6CO, d 2.04). IR spectra were measured
on a Nicolet Avatar-320 instrument and referenced to polystyrene
standard, using cells equipped with calcium fluoride windows. MS
spectra were recorded on a JEOL SX-102A spectrometer. Solvents
were dried and deoxygenated by refluxing over the appropriate re-
agents before use. n-Hexane, diethyl ether, THF and benzene were
distilled from sodium-benzophenone. Acetonitrile and dichloro-
methane were distilled from calcium hydride, and methanol was
distilled from magnesium. All other solvents and reagents were
of reagent grade and used as received. Elemental analyses and X-
ray diffraction studies were carried out at the Regional Center of
Analytical Instrument located at the National Taiwan University.
Mo(CO)6 and C3H5Br were purchased from Strem Chemical,
EtOCS2K, dppm, dppe, and dppa, were purchased from Merck.
Method A: A solution of C5H10NC(S)SH (0.161 g, 1.0 mmol) in
MeOH (5 ml) was added to a flask containing 1 (0.355 g, 1.0 mmol)
in CH2Cl2 (20 ml). The solution was stirred for 1 min and a yel-
low-orange precipitate formed. The precipitate was collected by
filtration (G4), washed with n-hexane (2 ꢁ 10 ml) and then dried
in vacuo to yield 0.35 g (99%) of 3. IR (KBr)
1917(vs), 1865(vs), 1847(vs) cmꢀ1
298 K): 1.17 (d, 2H, Hanti, JH–H = 9.8 Hz), 1.50 (m, 6H,
t
(CO) 1945(vs),
.
1H NMR (200 MHz, DMSO-d6,
d
NCH2CH2CH2), 3.13 (d, 2H, Hsyn, JH–H = 6.4 Hz), 3.83 (m, 4H,
NCH2), 4.00 (m, 1H, CH of allyl). 13C{1H} NMR (50 MHz, DMSO-d6,
298K): d 23.7 (s, NCH2CH2CH2), 25.7 (s, NCH2CH2), 48.0 (s, NCH2),
58.1 (s, CH@CH2), 74.7 (s, CH2@CH), 204.2 (s, CS2), 230.1 (s, CO).
MS (EI, 20 eV): m/z 355 (M+), 327 (M+ꢀCO), 299 (M+ꢀ2CO). Anal.
Calc. for C11H15NO2S2Mo: C, 37.39; H, 4.28; N, 3.97. Found: C,
37.52; H, 4.42; N, 3.75%.
MethodB: An aliquot of CS2 (0.1 ml, 1.6 mmol) was added to a solu-
tion of 2 (0.399 g, 1.0 mmol) in CH2Cl2 (20 ml). Instantly, the reac-
tion is completely. A yellow-orange precipitate was formed which
was isolated by filtration (G4), and was washed with n-hexane
(2 ꢁ 10 ml) and subsequently dried under vacuum to yield 0.33 g
(94%) of 3.
4.2. Preparation of 1
MeOH (20 ml) was added to a flask (100 ml) containing a mix-
4.5. Preparation of 4
ture of EtOCS2K (0.160 g, 1.0 mmol) and [Mo(CH3CN)2(g3
-
C3H5)(CO)2(Br)] [17] (0.317 g, 1.0 mmol). The solution was stirred
for 10 min, and an IR spectrum indicated completion of the reac-
tion. After removal of the solvent in vacuo, the residue was redis-
solved with CH2Cl2 (10 ml). n-Hexane (25 ml) was added to the
solution and a red solids 1 were formed which were isolated by fil-
MeOH (20 ml) was added to a flask (100 ml) containing a
mixture of bipy (0.228 g, 1.0 mmol) and [Mo(CH3CN)(g3
-
C3H5)(CO)2(S2COEt)] (1) (0.355 g, 1.0 mmol) at ambient tempera-
ture. Instantly, the reaction mixture turned to red and a red
precipitate was formed. The precipitate was collected by filtration

3310
K.-H. Yih, G.-H. Lee / Journal of Organometallic Chemistry 693 (2008) 3303–3311
(G4) and dried in vacuo to yield 0.46 g (98%) of [Mo(g3
C3H5)(CO)2(S2COEt)(bipy)] (4). Spectroscopic data of 4 are as fol-
lows. IR (KBr, cmꢀ1): (CO) 1932(vs), 1858(vs). 1H NMR
(500 MHz, CDCl3, 298 K): d 1.52 (d, 2H, Hanti, JH–H = 4.74 Hz),
1.62 (t, 3H, OCH2CH3, JH–H = 7.12 Hz), 2.94 (m, 1H, Hc), 3.03 (d,
2H, Hsyn, JH–H = 5.83 Hz), 4.77 (q, 2H, OCH2, JH–H = 7.12 Hz), 7.41
-
The solution was stirred for 10 min and the solvent was removed
in vacuo till about 5 ml. Methanol (15 ml) was added to the flask
and the solution was stored at ꢀ18 °C for 12 h to give yellow pre-
cipitates. The precipitate was collected by filtration (G4) washed
with n-hexane (2 ꢁ 10 ml) and then dried in vacuo yielding
t
0.69 g (96%) of [Mo(
troscopic data of 7 are as follows. IR (KBr, cmꢀ1):
1850(vs). 31P{1H} NMR (202 MHz, CDCl3, 298 K): 7: d 29.4 (s, dppe).
1H NMR (500 MHz, CDCl3, 298 K): d 1.40 (t, 3H, OCH2CH3, JH–H
g
3-C3H5)(S2COEt)(CO)2]2(
l
-dppe)] (7). Spec-
(d, 2H, H1 of bipy, JH–H = 6.49 Hz), 7.91 (t, 2H, H2 of bipy, JH–H
=
t(CO) 1942(vs),
7.43 Hz), 8.03 (t, 2H, H3 of bipy, JH–H = 8.18 Hz), 8.70 (d, 2H, H4 of
bipy, JH–H = 5.20 Hz). 13C{1H} NMR (125 MHz, CDCl3, 298 K): d
14.0 (s, OCH2CH3), 55.3 (s, OCH2), 70.5 (s, CH@CH2), 75.9 (s,
CH2@CH), 122.0, 126.1, 138.0, 152.6 (s, C of bipy), 224.9 (s, CS2),
227.6 (s, CO). MS (FAB, NBA, m/z) 471 (M+), 430 (M+ꢀC3H5). Anal.
Calc. for C18H18N2O3S2Mo: C, 45.95; H, 3.86 ; N, 5.96. Found: C,
46.05; H, 3.95; N, 5.52%.
=
7.1 Hz), 4.62 (m, 2H, OCH2), 1.57 (m, 2H, Hanti), 3.75 (m, 2H, Hsyn),
2
3.65 (dm, 4H, PCH2, JP–H = 35.0 Hz), 4.88 (m, 1H, Hcentre), 7.27–
7.60 (m, 20H, Ph). 13C{1H} NMR (125 MHz, CDCl3, 298 K): d 14.0
(br, OCH2CH3), 29.6 (t, PCH2, JP–C = 10.4 Hz), 70.0 (br, OCH2), 60.5
(s, CH@CH2), 82.4 (br, CH2@CH), 128.4–137.2 (m, Ph), 214.0 (s,
CS2), 224.1 (s, CO). MS (FAB, NBA, m/z): 1026 (M+), 998 (M+ꢀCO).
Anal. Calc. for C42H44O6P2S4Mo2: C, 49.12; H, 4.32. Found: C,
49.82; H, 4.53%.
4.6. Preparation of endo-, exo-5
MeCN (20 ml) was added to a flask (100 ml) containing a
mixture of dppm (0.384 g, 1.0 mmol) and [Mo(CH3CN)(g3
-
4.9. Preparation of endo-, exo-8
C3H5)(CO)2(S2COEt)] (1) (0.355 g, 1.0 mmol). The solution was
refluxed for 1 h, and an IR spectrum indicated completion of the
reaction. After removal of the solvent in vacuo, the residue was
redissolved with CH2Cl2 (10 ml). n-Hexane (25 ml) was added to
the solution and a yellow-orange solids 2 were formed which were
isolated by filtration (G4), washed with n-hexane (2 ꢁ 10 ml) and
subsequently dried under vacuum yielding a mixture of endo-,
The synthesis and work-up were similar to those used in the
preparation of complex 5. The complex endo-, exo-[Mo(g3
-
C3H5)(S2COEt)(CO)(dppa)] (endo-, exo-8) was isolated in 92% yield
as a yellow-orange microcrystalline solid. Spectroscopic data of 8
are as follows. IR (KBr, cmꢀ1):
t
(CO) 1824(vs). 31P{1H} NMR
2
(202 MHz, CDCl3, 298 K): exo-8: d 62.2, 91.4 (d, JP–P = 76.9 Hz),
2
exo-[Mo(
g
3-C3H5)(S2COEt)(CO)(dppm)] (endo-, exo-5) (0.59 g,
endo-8: d 63.2, 98.0 (d, JP-P = 63.2 Hz). 1H NMR (500 MHz, CDCl3,
88%) as a yellow-orange microcrystalline solid. Further purification
was accomplished by recrystallization from 1/10 CH2Cl2/n-hexane.
Spectroscopic data of 5 are as follows. endo, exo-5: IR (KBr,
298 K): d 1.00, 1.06 (t, 6H, OCH2CH3), 2.29, 2.37, 2.62, 2.72 (d, br,
4H, Hanti, JH–H = 11.6 Hz), 3.50, 3.87, 4.05 (br d, 4H, Hsyn, JH–H
=
4.8 Hz), 3.69, 3.97 (m, 4H, OCH2), 5.03, 5.11 (m, 2H, Hcentre),
6.88–7.81 (m, 40H, Ph). 13C{1H} NMR (125 MHz, CDCl3, 298 K): d
13.6 (s, OCH2CH3), 66.9 (s, OCH2), 50.7, 70.5 (s, CH@CH2), 98.0,
102.9 (s, CH2@CH), 126.8–139.3 (m, Ph), 222.9 (s, CS2), 226.6 (s,
CO). MS (FAB, NBA, m/z): 643 (M+ꢀCO), 602 (M+ꢀCOꢀC3H5). Anal.
Calc. for C31H31NO2P2S2Mo: C, 55.44; H, 4.65; N, 2.09. Found: C,
55.76; H, 4.30; N, 2.04%.
t
CO/cmꢀ1): 1801(vs). MS (FAB, NBA, m/z): 672 (M+), 644
(M+ꢀCO). 31P{1H} NMR (202 MHz, CDCl3, 298 K): endo-5: d 6.9,
2
2
32.8 (d, dppm, JP–P = 52.7 Hz), exo-5: d 3.4, 27.4 (d, dppm, JP-P
=
63.1 Hz), 1H NMR (500 MHz, CDCl3, 298 K): d 1.10 (t, 3H, OCH2CH3,
JH–H = 11.7 Hz), 2.24, 2.55 (d, 2H, Hanti, JH–H = 13.3 Hz), 2.42, 4.00
(m, 2H, Hsyn), 3.99, 4.22 (m, 2H, PCH2), 4.01 (m, 2H, OCH2CH3),
4.91 (m, 1H, Hcentre). 13C{1H} NMR (125 MHz, CDCl3, 298 K): d
13.7 (s, OCH2CH3), 41.5 (t, PCH2, JP–C = 20.5 Hz), 54.7, 68.9 (s, termi-
nal C of allyl), 66.7 (s, OCH2), 100.6 (s, center C of allyl), 222.5 (s,
CS2), 227.1 (s, CO). MS (FAB, NBA, m/z) 671 (M+), 630 (M+ꢀC3H5).
Anal. Calc. for C32H32O2P2S2Mo: C, 57.31; H, 4.81. Found: C,
57.52; H, 4.61%.
4.10. Single-crystal X-ray diffraction analyses of 1b, exo-5, and endo,
exo-8
Single crystals of 1b, exo-5 and endo, exo-8 suitable from X-ray
diffraction analyses were grown by recrystallization from 20:1 n-
hexane/CH2Cl2. The diffraction data were collected at room tem-
perature on an Enraf-Nonius CAD4 diffractometer equipped with
4.7. Preparation of endo-, exo-6
graphite-monochromated Mo K
a (k = 0.71073 Å) radiation. The
The synthesis and work-up were similar to those used in the
raw intensity data were converted to structure factor amplitudes
and their esd’s after correction for scan speed, background, Lorentz,
and polarization effects. An empirical absorption correction, based
on the azimuthal scan data, was applied to the data. Crystallo-
graphic computations were carried out on a Microvax III computer
using the NRCC-SDP-VAX structure determination package [18].
A suitable single crystal of 1b was mounted on the top of a glass
fiber with glue. Initial lattice parameters were determined from 24
accurately centered reflections with h values in the range from
2.10° to 27.50°. Cell constants and other pertinent data were col-
lected and are recorded in Table 1. Reflection data were collected
using the h/2h scan method. Three check reflections were mea-
sured every 30 min throughout the data collection and showed
no apparent decay. The merging of equivalent and duplicate reflec-
tions gave a total of 6230 unique measured data in which 3231
preparation of complex endo-, exo-5. The complex endo-, exo-
[Mo(g
3-C3H5)(S2COEt)(CO)(dppe)] (endo-, exo-6) was isolated in
85% yield as a yellow-orange microcrystalline solid. Spectroscopic
data of 6 are as follows. IR (KBr, cmꢀ1):
t
(CO) 1798(vs). 31P{1H}
2
NMR (202 MHz, CDCl3, 298 K): endo-6: d 28.7, 32.6 (d, JP–P
=
2
26.0 Hz), exo-6: d 29.4, 44.8 (d, JP–P = 42.2 Hz). exo-6: 1H NMR
(200 MHz, CDCl3, 298 K): d 0.98 (t, 3H, OCH2CH3, JH–H = 7.0 Hz),
1.44, 1.47 (d, 2H, Hanti, JH–H = 7.1 Hz), 2.21 (m, 2H, Hsyn), 3.52,
3.77 (m, 4H, PCH2), 4.02 (m, 1H, Hc), 4.18 (m, 2H, OCH2), 7.06–
7.69 (m, 20H, Ph). 13C{1H} NMR (50 MHz, CDCl3, 298 K): d 12.6 (s,
OCH2CH3), 25.7 (m, PCH2), 69.9 (s, OCH2), 59.0, 60.5 (s, CH@CH2),
82.5 (s, CH2@CH), 127.1–137.2 (m, Ph), 224.1 (s, CS2), 228.5 (s,
CO). MS (FAB, NBA, m/z): 686 (M+), 658 (M+ꢀCO). Anal. Calc. for
C33H34O2P2S2Mo: C, 57.89; H, 5.01. Found: C, 58.06; H, 5.20%.
reflections with I > 2r(I) were considered observed. The structure
4.8. Preparation of 7
was first solved by using the heavy-atom method (Patterson syn-
thesis), which revealed the positions of metal atoms. The remain-
ing atoms were found in a series of alternating difference Fourier
maps and least-squares refinements. The quantity minimized by
Dppe (0.198 g, 0.5 mmol) was dissolved in CH2Cl2 (5 ml) and
the solution was added slowly to a flask containing a solution of
1 (0.355 g, 1.0 mmol) in CH2Cl2 (10 ml) during a period of 5 min.
the least-squares program was
x
(|Fo| ꢀ |Fc|)2, where
x is the

K.-H. Yih, G.-H. Lee / Journal of Organometallic Chemistry 693 (2008) 3303–3311
3311
(d) F. Dewans, J. Dewailly, J. Meuniert-Piret, P. Piret, J, Organomet. Chem. 76
(1974) 53.
[2] (a) R.H. Fenn, A.J. Graham, J. Organomet. Chem. 37 (1972) 137;
(b) A.J. Graham, D. Akrigg, B. Sheldrick, Cryst. Struct. Commun. 24 (1976)
173;
weight of a given operation. The analytical forms of the scattering
factor tables for the neutral atoms were used [19]. The non-hydro-
gen atoms were refined anisotropically. Hydrogen atoms were in-
cluded in the structure factor calculations in their expected
positions on the basis of idealized bonding geometry but were
not refined in least squares. All hydrogens were assigned isotropic
thermal parameters 1ꢀ2 Å2 larger then the equivalent Biso value of
the atom to which they were bonded. The final residuals of this
refinement were R = 0.017 and Rw = 0.044. Selected bond distances
and angles are listed in Table 2.
The procedures for exo-5 and endo, exo-8 were similar to those
for 1b. The final residuals of this refinement were R = 0.036 and
Rw = 0.076 for exo-5, and R = 0.035 and Rw = 0.078 for endo, exo-
8. Selected bond distances and angles are listed in Table 2. Tables
of thermal parameters and selected final atomic coordinates are gi-
ven in the Supplementary material.
(c) F.A. Cotton, C.A. Murillo, B.R. Stults, Inorg. Chim. Acta 7 (1977) 503;
(d) C.A. Cosky, P. Ganis, G. Avatabile, Acta. Crystallogr., Sect. B B27 (1971)
1859;
(e) J.W. Faller, D.F. Chodosh, D. Katahira, J. Organomet. Chem. 187 (1980) 227;
(f) F.A. Cotton, M. Jeremic, A. Shaver, Inorg. Chim. Acta 6 (1972) 543;
(g) B.J. Brisdon, A.A. Woolf, J. Chem. Soc., Dalton Trans. (1978) 291;
(h) B.J. Brisdon, A. Day, J. Organomet. Chem. 221 (1981) 279.
[3] M.D. Curtis, O. Eisenstein, Organometallics 3 (1984) 887.
ˇ
[4] P. Espinet, R. Hernando, G. Iturbe, F. Villafane, A.G. Orpen, I. Pascual, Eur. J.
Inorg. Chem. (2000) 1031.
[5] K.H. Yih, G.H. Lee, Y. Wang, Inorg. Chem. Commun. 3 (2000) 458.
[6] K.H. Yih, G.H. Lee, S.L. Huang, Y. Wang, Organometallics 21 (2002) 5767.
[7] K.B. Shiu, K.H. Yih, S.L. Wang, F.L.J. Liao, Organomet. Chem. 420 (1991) 359.
[8] K.H. Yih, G.H. Lee, Y. Wang, J. Organomet. Chem. 588 (1999) 125.
[9] K.-H. Yih, S.-C. Chen, Y.-C. Lin, M.-C. Cheng, Y. Wang, J. Organomet. Chem. 494
(1995) 149.
[10] G. Barrado, D. Miguel, V. Riera, S. Garcia-Granda, J. Organomet. Chem. 489
(1995) 129.
Acknowledgment
[11] (a) B.J. Brisdon, G.F. Griffin, J. Chem. Soc., Dalton Trans. (1975) 1999;
(b) B.J. Brisdon, A.A. Woolf, J. Chem. Soc., Dalton Trans. (1978) 291.
[12] (a) S. Trofimenko, Acc. Chem. Res. 4 (1971) 17;
(b) F.A. Cotton, A.G. Stanislowski, J. Am. Chem. Soc. 96 (1974) 5074;
(c) D.J. Bevan, R.J. Mawby, J. Chem. Soc., Dalton Trans. (1980) 1904.
[13] J.W. Faller, D.A. Haitko, R.D. Adams, D.F. Chodosh, J. Am. Chem. Soc. 101 (1979)
865.
We thank the National Science Council of Taiwan, the Republic
of China (NSC96-2113-214-001) for support.
Appendix A. Supplementary material
[14] (a) S.K. Chowdhury, M. Nandi, V.S. Joshi, A. Sarkar, Organometallics 16 (1997)
1806 and references cited therein;
For 1b, 5b and 8 tables of atomic coordinates, crystal and inten-
sity collection data, anisotropic thermal parameters, and bond dis-
tances and bond angles. Supplementary data associated with this
article can be found, in the online version, at doi:10.1016/
j.jorganchem.2008.07.025.
(b) M. Kollmar, B. Goldfuss, M. Reggelin, F. Rominger, G. Helmchen, Chem. Eur.
J. 7 (2001) 4913.
[15] B.J. Brisdon, D.A. Ewards, K.E. Paddick, M.G.B. Drew, J. Chem. Soc., Dalton Trans.
(1980) 1317.
[16] (a) A. Gorfti, M. Salmain, G. Jaouen, M. McGlinchey, A. Bennnouna, A. Mousser,
Organometallics 15 (1996) 142;
(b) D.R. van Staveren, T. Weyhermuller, N. Metzler-Nolte, Organometallics 19
(2000) 3730.
References
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