Preparations of cobalt-containing phosphines and reactions toward dicobalt octacarbonyl

Article abstract of DOI:10.1016/j.jorganchem.2003.09.003

Treatments of bis(diphenylphosphino)methylene (dppm) bridged dicobalt complex, Co₂(CO)₆(μ-Ph₂PCH ₂PPh₂), with alkynes, Ph₂PC≡CR (2: R=CMe₃; 3: R=SiMe₃), at 60 °C in TH

Full text of DOI:10.1016/j.jorganchem.2003.09.003

Journal of Organometallic Chemistry 688 (2003) 161ꢂ167
/
www.elsevier.com/locate/jorganchem
Preparations of cobalt-containing phosphines and reactions toward
dicobalt octacarbonyl
Fung-E Hong *, Yi-Chun Lai, Yi-Jung Ho, Yu-Chang Chang
Department of Chemistry, National Chung-Hsing University, Taichung 40227, Taiwan
Received 10 June 2003; received in revised form 12 August 2003; accepted 21 August 2003
Abstract
Treatments of bis(diphenylphosphino)methylene (dppm) bridged dicobalt complex, Co2(CO)6(m-Ph2PCH2PPh2), with alkynes,
Ph2PCꢀ
Ph2PCꢀ
formations of unexpected tetra-cobalt clusters, [(m-Ph2PCH2PPh2)(m-PPh2)Co4(CO)7(m4,m2-CCR)] (6: Rꢀ
/
CR (2: Rꢀ
/
CMe3; 3: Rꢀ
/
SiMe3), at 60 8C in THF for 6 h gave alkyne-bridged complexes [(m-Ph2PCH2PPh2)Co2(CO)4][(m-
/
CR)] (4: Rꢀ
/
CMe3; 5: Rꢀ
/
SiMe3). Further reactions of 4 and 5 with Co2(CO)8 at 80 8C in toluene for 3 h resulted in the
CMe3; 7: RꢀSiMe3). All
/
/
these compounds were characterized by spectroscopic means; 5, 6 and 7 were studied by X-ray diffraction methods as well. The
structure of 6 (or 7) can be looked upon as a tetra-cobalt arachno cluster being coordinated with phosphine ligands and linked by
organic moiety.
# 2003 Elsevier B.V. All rights reserved.
Keywords: Alkyne-bridged dicobalt-complex; Metal-containing phosphine; Tetracobalt cluster; arachno Cluster
1. Introduction
Mo(CO)6 gave a 1-chelated molybdenum complex, [(m-
Ph2PCH2PPh2)Co2(CO)4][(m-P,P-Ph2PCꢀCPPh2)-
/
The exploitation of new and effective phosphine
ligands has always been vital to the success of the
phosphine-modified, transition-metal based catalytic
reactions [1]. In the past, efforts were mainly focused
on preparing phosphine ligands derived from pure
organic substances, which have done a great job in
many designated cases [2]. Nevertheless, reports on the
preparations of the metal-containing phosphines are
rare and their catalytic potential remained to be
explored [3].
Mo(CO)4] [4]. In this regard, 1 acts as a genuine di-
phosphine chelating ligand. It can be looked upon as a
modified form of 1,2-bis(diphenylphosphino)ethane
(dppe)*a rather frequently used bidentate phosphine
/
ligand [5]. It has also been demonstrated that 1 might act
as chelating or bridging di-phosphine ligand toward
various transition metals such as tungsten, ruthenium,
gold and palladium and form 1-chelated (or bridged)
metal complexes [6].
We have previously described the preparation of a
new type of metal-containing bidentate phosphines, [(m-
Ph2PCH2PPh2)Co2(CO)4(m-PPh2Cꢀ
/
CPPh2)] (1), which
was prepared from the reaction of a bi-functional ligand
bis(diphenylphosphino)acetylene (dppa) with one
equivalent of
a
bis(diphenylphosphino)methylene
Following the same strategy, cobalt-containing mono-
dentate phosphines might be prepared started with
(dppm) bridged dicobalt complex, Co2(CO)6(m-
Ph2PCH2PPh2). (Diagram 1). The reaction of 1 with
alkynyl phosphines having the formula of Ph2PCꢀ
/
CR.
We report herein the preparations of a new type of
cobalt-containing monodentate phosphines and their
reactions toward dicobalt carbonyls.
* Corresponding author. Fax: ꢁ886-4-2286-547.
E-mail address: fehong@dragon.nchu.edu.tw (F.-E. Hong).
/
0022-328X/03/$ - see front matter # 2003 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2003.09.003

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F.-E. Hong et al. / Journal of Organometallic Chemistry 688 (2003) 161ꢂ
/
167
2. Results and discussion
Table 1
Crystal data of 5, 6 and 7
Treatments of the dppm-bridged dicobalt complex,
Co2(CO)6(m-Ph2PCH2PPh2), with alkynyl phosphines,
Compound
5
6
7
Formula
Formula
weight
C
896.65
46H41Co2O4P3Si C51H41Co4O8P3 C50H41Co4O8P3Si
1110.47
Ph2PCꢀ
/
CR (2: Rꢀ
/
CMe3; 3: RꢀSiMe3), at 60 8C in
/
1126.55
THF for 6 h gave alkyne-bridged complexes [(m-
Ph2PCH2PPh2)Co2(CO)4][(m-Ph2PCꢀCR)] (4: Rꢀ
CMe3; 5: RꢀSiMe3) [7] (Scheme 1). Compounds 4
/
/
Crystal sys- Monoclinic
tem
Space group P2(1)/n
Triclinic
Monoclinic
/
¯
P1
P2(1)/n
and 5 were characterized by spectroscopic means. The
31P-NMR spectrum of 4 shows two singlets in the ratio
˚
a (A)
13.0289(11)
25.793(2)
13.1245(11)
11.198(4)
11.977(4)
20.023(6)
103.807(6)
101.029(6)
101.574(6)
2472.8(13)
2
12.5584(10)
21.4358(16)
24.4529(10)
˚
b (A)
of 2:1 at 34.7 and ꢃ
phosphorous atoms. The matching signals are 34.7 and
11.3 ppm in 5. The upfielded signal corresponds to
/6.2 ppm, respectively, for all three
˚
c (A)
a (8)
b (8)
g (8)
ꢂ
/
ꢂ
/
97.556(2)
103.5980(10)
ꢃ
/
ꢂ
/
ꢂ
/
the unbound phosphorous atom and they are 5 ppm
apart. In 1H-NMR, there are two distinct chemical
shifts, 3.32 and 4.25 ppm, being observed for the
methylene protons of 4. The corresponding peaks are
3.15 and 4.85 ppm in 5. Slightly different chemical shifts
were perceived for these two sets of signals. Also, two
signals at 203.1 and 207.8 ppm were found and assigned
as the carbonyls of 4 in 13C-NMR. The matching signals
are 201.1 and 207.8 ppm in 5.
3
˚
V (A )
Z
Dcalc (Mg
4372.2(6)
4
1.362
5090.2(7)
4
1.470
1.491
mꢃ3
)
l(Moꢂ
/
Ka)
0.71073
0.937
0.71073
1.467
0.71073
1.449
˚
(A)
m (mmꢃ1
2urange (8)
)
2.07ꢂ
/
26.01
1.82ꢂ
3284
/
26.09
1.90ꢂ26.04
5564
/
Observed re- 4859
flections
(F ꢁ4s(F))
/
Suitable crystals of 5 were obtained from mixture
Number of
refined para-
meters
aR1 for sig-
nificant re-
flections
bwR2 for sig- 0.0793
nificant re-
flections
cGoodness-
of-fit
505
585
603
solvent (CH2Cl2ꢂ
/
hexaneꢀ1:1) at 4 8C and their struc-
/
tures were determined by X-ray diffraction method
(Table 1). The ORTEP of 5 is depicted in Fig. 1. The
0.0396
0.0884
0.2238
0.954
0.0350
0.0958
1.036
structural study of 5 reveals that the alkyne, Ph2PCꢀ
CSiMe3, bridges the dicobalt fragment Co2(CO)4(m-
Ph2PCH2PPh2). The bulky substituent, ꢁSiMe3, keeps
/
/
away from the crowded dppm environs. The bridged
dppm takes the axial position of the cobalt center, which
is in accord with the common observation for phosphine
substituted alkyne-bridged dicobalt complexes [8]. Jud-
ging from its structure, 5 is a promising bulky, metal-
containing, monodentate phosphine. Unfortunately,
attempts to grow crystals for 4 resulted in failure.
Although the crystal structure of 4 is not available, it
is believed, based on the accumulated spectroscopic
data, that a similar framework was held for 4 and 5.
0.883
a
R1ꢀ
/
½S(½Fo½ꢃ
wR2ꢀ
{S[w(F2oꢃ
4, 6 and 7.
/
½Fc½)/½SFo½½.
b
/
/
F2c)2/S[w(Fo2)2}}1/2; wꢀ
/
0.10, 0.0727, 0.1081 for
c
GoFꢀ
/
[Sw(F2oꢃ
/
F2c)2/(Nrflns
ꢃ .
Nparams)]1/2
/
Further reactions of 4 and 5 with Co2(CO)8 at 80 8C
in THF for 3 h resulted in the formations of unexpected
Scheme 1.

F.-E. Hong et al. / Journal of Organometallic Chemistry 688 (2003) 161ꢂ
/
167
163
simply find the expected 4- (or 5-) coordinated dicobalt
complex. Compound 6 and 7 were characterized by
spectroscopic means as well as X-ray diffraction meth-
ods. There are three singlets in the ratio of 1:1:1 at 39.3,
44.9 and 194.7 ppm, respectively, being observed for all
three phosphorous atoms of 6 in 31P-NMR spectrum.
The matching signals are 44.3, 48.3 and 193.5 ppm in 7.
The highly downfielded signal corresponds to the
bridged phosphido atom; while the other two signals
represent the bridged dppm. One triplet at 3.37 ppm was
found for the methylene protons of 6 in 1H-NMR.
Nevertheless, two distinct chemical shifts at 3.31 and
3.39 ppm were observed for the methylene protons in 7.
It indicates that the thermal motion of the coordinated
dppm, which swings back and forth around the dicobalt
fragment, in 6 is faster than that of 7 [4]. Slow
decompositions of compounds 6 and 7 were observed
while taking long hours NMR, which is in contrast with
the robustness of 4 or 5 in solution.
The reddish-black crystals of 6 and 7 were grown in
mixed solvent (CH2Cl2ꢂ
/
hexaneꢀ1:1) at 4 8C and were
/
sampled and subjected for the X-ray crystal structural
determination (Table 1). The ORTEPs of 6 and 7 are
depicted in Figs. 2 and 3. There is one CH3OH molecule
in each asymmetric unit of 7. Their corresponding
geometrical data are quite close except for some small
variations. The structure of 6 (or 7) can be regarded as a
tetra-cobalt arachno cluster being coordinated with
phosphines as well as connected with organic moiety
[10]. The dppm remains bridging on the two cobalt
atoms, Co(1) and Co(2), of the newly formed tetra-
cobalt arachno cluster. It is obvious that the two cobalt
atoms, Co(3) and Co(4), must come from the latterly
added reactant, Co2(CO)8. Interestingly, a phosphido
ligand, bridging Co(2) and Co(4), is found on the
Fig. 1. ORTEP drawing with the numbering scheme of 5. Some carbon
˚
and hydrogen atoms are omitted for clarity. Selected bond lengths (A)
and angles (8): Co(1)ꢁ
2.2371(9); Co(1)ꢁCo(2) 2.4825(6); Co(2)ꢁ
1.995(3); Co(2)ꢁP(3) 2.2181(9); SiꢁC(2) 1.859(3); P(1)ꢁ
P(2)ꢁC(46) 1.843(3); P(3)ꢁC(46) 1.827(3); C(1)ꢁC(2) 1.344(4); C(2)ꢁ
Co(1)ꢁC(1) 39.48(12); C(2)ꢁCo(1)ꢁP(2) 136.86(10); C(1)ꢁCo(1)ꢁP(2)
100.70(9); C(2)ꢁCo(1)ꢁCo(2) 51.57(9); C(1)ꢁCo(1)ꢁCo(2) 51.26(8);
P(2)ꢁCo(1)ꢁCo(2) 93.64(3); C(1)ꢁCo(2)ꢁC(2) 39.48(11); C(1)ꢁ
Co(2)ꢁP(3) 95.56(9); C(2)ꢁCo(2)ꢁP(3) 134.55(9); C(1)ꢁCo(2)ꢁCo(1)
51.53(8); C(2)ꢁCo(2)ꢁCo(1) 51.31(8); P(3)ꢁCo(2)ꢁCo(1) 100.45(3);
C(46)ꢁP(2)ꢁCo(1) 112.50(10); C(46)ꢁP(3)ꢁCo(2) 110.76(10); C(2)ꢁ
C(1)ꢁP(1) 150.1(2); Co(2)ꢁC(1)ꢁCo(1) 77.21(11); C(1)ꢁC(2)ꢁSi
152.5(3); C(1)ꢁC(2)ꢁCo(1) 70.48(17); C(1)ꢁC(2)ꢁCo(2) 69.89(18);
Co(1)ꢁC(2)ꢁCo(2) 77.13(11); P(3)ꢁC(46)ꢁP(2) 113.12(16).
/
C(2) 1.988(3); Co(1)ꢁ
C(1) 1.986(3); Co(2)ꢁ
C(1) 1.800(3);
/
C(1) 1.993(3); Co(1)ꢁ
/
P(2)
/
/
/C(2)
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
tetra-cobalt
clusters,
[(m-Ph2PCH2PPh2)(m-
CMe3; 7: Rꢀ
cluster. It has to come from the breaking of the Cꢁ
PPh2 bond of the original bridging alkynyl phosphines,
CR.
Selected structural parameters of 6 and 7 were shown
in Table 2 for comparison. The geometrical data of these
/
PPh2)Co4(CO)7(m4,m2-CCR)] (6: Rꢀ
/
/
SiMe3) with high yield [9] (Scheme 1). Actually, the
reaction can be started from a lower temperature such as
55 8C and with moderate yield. Interestingly, we did not
Ph2PCꢀ
/

164
F.-E. Hong et al. / Journal of Organometallic Chemistry 688 (2003) 161ꢂ167
/
Fig. 2. ORTEP drawing with the numbering scheme of 6. Some carbon and hydrogen atoms are omitted for clarity.
two compounds’ main frameworks are rather close. The
bond angle of the C(1)ꢁC(2)ꢁSi in 7 is much steeper
than that of C(1)ꢁC(2)ꢁC(3) in 6. The dihedral angels
for the Co4 butterfly structures, Co(1)ꢁCo(2)ꢁCo(3)ꢁ
Co(4), are 135.18 and 132.88 for 6 and 7, respectively.
They are much wilder than the common observed Co4C2
butterfly structures, which range from 1008 to 1208 [11].
Diagrams of simplified structures of 6 and 7 were
drawn (Diagram 2). The atom numbering of the main
structures of these two compounds has been kept the
same. Looking from the top, the C(1) atom is above the
center of the four cobalt atoms. The C(2) atom is
connected to C(1) on the left and ascending up to the
/
/
/
/
/
/
/
right. The C(1)ꢁ
bond. The dppm ligand is above the Co(1)ꢁ
Co(3) plane; while the phosphido ligand is below the
Co(2)ꢁCo(3)ꢁCo(4) plane. As shown from the side
view, this cluster can be regarded as a tetra-cobalt
/
C(2) bond bisects the Co(3)ꢁ
/
Co(4)
/
Co(2)ꢁ
/
/
/
Fig. 3. ORTEP drawing with the numbering scheme of 7. Some carbon and hydrogen atoms are omitted for clarity.

F.-E. Hong et al. / Journal of Organometallic Chemistry 688 (2003) 161ꢂ
/
167
165
Table 2
Comparison of selected structural parameters of 6 and 7
solvents were used. All processes of separations of the
products were performed by Centrifugal Thin Layer
Chromatography (CTLC, Chromatotron, Harrison
6
7
1
model 8924). H-NMR spectra were recorded (Varian
Bond length
VXR-300S spectrometer) at 300.00 MHz; chemical
shifts are reported in ppm relative to internal CHCl3
or CH2Cl2. 31P- and 13C-NMR spectra were recorded at
Co(1)ꢁ
Co(2)ꢁ
Co(3)ꢁ
Co(3)ꢁ
Co(1)ꢁ
Co(2)ꢁ
C(1)ꢁ
C(1)ꢁ
C(1)ꢁ
C(1)ꢁ
C(1)ꢁ
C(2)ꢁ
C(2)ꢁ
C(2)ꢁ
C(2)ꢁ
P(3)ꢁ
P(3)ꢁ
/
Co(2)
Co(3)
Co(4)
Co(1)
P(1)
2.4936(16)
2.5691(15)
2.4470(16)
2.5528(17)
2.197(2)
2.5180(6)
2.5890(5)
2.4517(6)
2.5472(6)
2.1888(9)
2.2101(8)
1.330(4)
1.899(3)
1.982(3)
1.991(3)
2.268(3)
2.205(3)
1.946(3)
1.859(3)
/
/
1
121.44 and 75.46 MHz, respectively. H-NMR spectra
/
of variable temperature experiments were recorded by
the same instrument. Some other routine 1H-NMR
spectra were recorded at Gemini-200 spectrometer at
200.00 MHz or Varian-400 spectrometer at 400.00
MHz. IR spectra of sample powder in KBr were
recorded on a Hitachi 270-30 spectrometer. Mass
spectra were recorded on JEOL JMS-SX/SX 102A
GC/MS/MS spectrometer. Elemental analyses were
recorded on Heraeus CHN-O-S-Rapid.
/
/P(2)
2.217(2)
/
C(2)
1.301(11)
1.932(7)
2.001(8)
/
Co(1)
Co(2)
Co(3)
Co(4)
Co(3)
Co(4)
Si
/
/
2.001(8)
/
2.306(8)
/
2.242(3)
/
1.912(9)
/
ꢂ/
/C(3)
1.547(13)
2.160(3)
2.217(2)
ꢂ/
/Co(4)
2.1451(9)
/Co(2)
2.2246(8)
4.2. Synthesis of 4 and 5
Bond angle
C(1)ꢁC(2)ꢁ
C(1)ꢁC(2)ꢁ
C(1)ꢁC(2)ꢁ
C(1)ꢁC(2)ꢁ
Co(1)ꢁ
Co(2)ꢁ
Co(1)ꢁ
Co(1)ꢁ
Co(1)ꢁ
Co(2)ꢁ
Co(4)ꢁ
Co(3)ꢁ
Co(4)ꢁ
Co(2)ꢁ
P(1)ꢁCo(1)ꢁ
P(2)ꢁCo(2)ꢁ
Into a 100 cm3 flask was placed dicobalt octacarbo-
nyl, Co2(CO)8 (0.342 g, 1.000 mmol) and dppm (0.385 g,
1.000 mmol) in 10 ml of THF. The solution was stirred
at 65 8C for 6 h and yielded yellow-colored Co2(CO)6(m-
/
/
Si
ꢂ
/
148.9(2)
/
/
C(3)
Co(3)
Co(4)
138.2(9)
62.3(5)
89.7(6)
60.54(3)
61.65(4)
78.7(3)
80.9(3)
141.3(4)
79.9(3)
68.8(2)
80.9(3)
71.7(3)
71.97(8)
97.61(7)
96.32(7)
ꢂ/
/
/
62.94(16)
85.42(19)
59.817(15)
61.491(15)
80.88(11)
81.78(10)
144.65(14)
81.33(10)
69.95(8)
/
/
/
Co(2)ꢁ
Co(3)ꢁ
C(1)ꢁ
C(1)ꢁ
C(1)ꢁ
C(1)ꢁ
C(1)ꢁ
C(1)ꢁ
C(2)ꢁ
P(3)ꢁ
/
Co(3)
Co(4)
/
/
P,P-PPh2CH2PPh2]. Further reaction with Ph2PCꢀ
/
/
/
Co(2)
Co(3)
Co(4)
Co(3)
Co(3)
Co(1)
Co(3)
CCMe3 2 (0.266 g, 1.000 mmol) in 5 ml of THF at
45 8C for 8 h yields a red solution. The solvent was
removed, and the resulting residue was chromatography
by CTLC. Complex [(m-Ph2PCH2PPh2)Co2(CO)4][(m-
/
/
/
/
/
/
/
/
/
/
81.78(10)
72.09(9)
Ph2PCꢀ
by mixed solvent (CH2Cl2ꢂ
60.0% (0.528 g, 0.600 mmol). Crystals were obtained
from the CH2Cl2ꢂhexane solution of 4 at 4 8C. The
/CCMe3] (4) was obtained from red band eluted
/
/
/
hexaneꢀ1:1) in the yield of
/
/
/
Co(4)
Co(2)
Co(1)
72.34(3)
97.04(3)
95.85(2)
/
/
/
/
/
same procedures were followed for the preparation of 5
with 3 as the alkyne source. Red colored compound was
obtained and identified as 5 in the yield of 63.0% (0.565
g, 0.630 mmol).
arachno cluster with Co4 butterfly framework or as a Cꢁ
EMe3 (E:Si or C) triangular face capped Co4C trigonal
bipyramidal cluster [12].
/
4.2.1. Characterization of 4
1H-NMR (CDCl3, d/ppm): 1.29 (s, 9H, CMe3), 3.32,
3. Summary
4.25 (m, 2H, dppm), 7.01ꢂ
(CDCl3, d/ppm): 33.18 (s, 3C, CH3), 37.65 (t, 1C,
dppm), 203.06, 207.75 (s, 2C, CO), 127.35ꢂ138.52
(36C, arene); 31P-NMR (CDCl3, d/ppm): 34.7 (s, 2P,
dppm), ꢃ6.2 (s, 1P, PPh2); E.A.: Calc.: C, 64.10; H,
/
7.47 (30H, arene); 13C-NMR
Two cobalt-containing bulky, monodentate phos-
phines 4 and 5 were synthesized. Their reactions with
Co2(CO)8 yielded unexpected tetra-cobalt clusters 6 and
7. It is a new pathway of making tetra-cobalt arachno
clusters with butterfly framework.
/
/
4.69. Found: C, 63.92; H, 5.07%; IR(KBr): n(CO) 2009(s),
1984(s), 1962(s); ESIMS: 880.93.
4.2.2. Characterization of 5
1H-NMR (CDCl3, d/ppm): 0.60 (s, 9H, SiMe3), 3.15,
4. Experimental
4.85 (m, 2H, dppm), 6.83ꢂ
(CDCl3, d/ppm): 1.83 (s, 3C, SiMe3), 37.56 (t, 1C,
dppm), 201.05, 207.74 (s, 2C, CO), 127.63ꢂ137.71 (36C,
arene); 31P-NMR (CDCl3, d/ppm): 34.7 (s, 2P, dppm),
11.3 (s, 1P, PPh2); E.A.: Calc.: C, 70.51; H, 6.78.
/
7.42 (30H, arene); 13C-NMR
4.1. General
/
All operations were performed in a nitrogen flushed
glove box or in a vacuum system. Freshly distilled
ꢃ
/

166
F.-E. Hong et al. / Journal of Organometallic Chemistry 688 (2003) 161ꢂ167
/
Found: C, 72.30; H, 6.41%; FABMS: 896; IR (KBr):
n(CO) 2015(s), 1990(s), 1955(s).
5. Supplementary material
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Center, CCDC nos. 211706, 211707, and 211708
for compounds 5, 6 and 7, respectively. Copies of this
information may be obtained free of charge from the
Director, CCDC, 12 Union Road, Cambridge CB2 1EZ,
4.3. Synthesis of 6 and 7
Into a 100 cm3 flask was placed dicobalt octacarbo-
nyl, Co2(CO)8 (0.047 g, 0.136 mmol) and 4 (0.120 g,
0.136 mmol) in 20 cm3 of toluene at 80 8C stirred for 3 h.
The solvent was removed under reduced pressure and
the resulting black residue was chromatographed by
Centrifugal Thin Layer Chromatography. A reddish-
UK (Fax: ꢁ44-1223-336033; e-mail: deposit@ccdc.ca-
/
m.ac.uk or www: http://www.ccdc.cam.ac.uk).
black band was eluted out by mixed solvent (CH2Cl2ꢂ
/
hexaneꢀ1:1) and was identified as 5 in the yield of
/
Acknowledgements
90.4% (0.133 g, 0.123 mmol). The same procedures were
followed for the preparation of 7 started with Co2(CO)8
(0.077 g, 0.226 mmol) and 5 (0.202 g, 0.226 mmol). A
reddish-black band was eluted out by mixed solvent
We thank the National Science Council of the R.O.C.
(Grant NSC-91-2113-M-005-017) for support.
(CH2Cl2ꢂ
/
hexaneꢀ1:1) and was identified as 6 in the
/
yield of 93.8% (0.239 g, 0.212 mmol).
References
4.3.1. Characterization of 6
1H-NMR (CDCl3, d/ppm):1.86 (s, 9H, CMe3), 3.37 (t,
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2H, dppm), 6.44ꢂ
d/ppm): 32.40 (s, 3C, CH3), 39.26 (t, 1C, dppm),
127.51ꢂ
140.31 (36C, arene); 31P-NMR (CDCl3, d/
/
7.85 (30H, arene); 13C-NMR (CDCl3,
(b) R. Noyori, Asymmetric Catalysis In Organic Synthesis, Wiley,
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/
(c) G.W. Parshall, S.D. Ittel, Homogeneous Catalysis, 2nd ed
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ppm): 39.3, 44.9 (s, 2P, dppm), 194.7 (s, 1P, m-PPh2);
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4.3.2. Characterization of 7
1H-NMR (CDCl3, d/ppm): 0.72 (s, 9H, SiMe3), 3.31,
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3.39 (m, 2H, dppm), 6.38ꢂ
7.73 (30H, arene); 13C-NMR
/
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/
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Suitable crystals of 5, 6, and 7 were sealed in thin-
walled glass capillaries under nitrogen atmosphere and
mounted on a Bruker AXS SMART 1000 diffract-
ometer. Intensity data were collected in 1350 frames
with increasing v (width of 0.38 per frame). The
absorption correction was based on the symmetry
equivalent reflections using SADABS program. The space
group determination was based on a check of the Laue
symmetry and systematic absences, and was confirmed
using the structure solution. The structure was solved by
direct methods using a SHELXTL package [13]. All non-H
atoms were located from successive Fourier maps and
hydrogen atoms were refined using a riding model.
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atoms, and fixed isotropic parameters were used for H
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summarized in Table 1.
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/
CCMe3 (2) or Ph2PCꢀCSiMe3 (3) was
/
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/
equivalent of n-butyllithium (2.0 M in cyclohexane), which was
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ophosphine (2.206 g, 10.000 mmol), which was dissolved in 5 ml

F.-E. Hong et al. / Journal of Organometallic Chemistry 688 (2003) 161ꢂ
/
167
167
of dimethyl ether, was again slowly added. The reaction mixture
was then allowed to warm to room temperature and stirred for
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33.6 (s, 1P, CꢀCP); 3: H-
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arene); 31P-NMR (CDCl3, d/ppm): ꢃ
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/
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idealized positions and held fixed with the CꢂH distances of 0.96
/
˚
A.