Alkyne Exchanges of Ta-Silylalkyne Complexes
Organometallics, Vol. 26, No. 1, 2007 181
Mp: 126-131 °C (dec). IR (nujol/CsI): 1246, 1194, 1110, 1028,
-30 °C for 2 days gave 10 (158 mg, 0.254 mmol) as pale yellow
crystals in 45% yield.
1
983, 938, 852 cm-1. H NMR (C6D6): δ 0.48 (s, 18H), 6.25 (t, J
1H NMR (CD2Cl2): δ 3.01 (s, 3H), 3.11 (s, 3H), 7.35-8.35 (m,
12H), 8.84 (s, 1H), 9.65 (s, 2H). 13C{1H} NMR (CD2Cl2): δ 30.2,
37.1, 123.7, 126.3, 127.9, 128.4, 130.9, 132.7, 134.2, 136.7, 138.7,
151.3, 186.6, 218.3, 247.3.
) 7.2 Hz, 6H), 6.49 (brs, 2H), 6.66 (t, J ) 8.0 Hz, 6H), 6.80 (brs,
1H), 8.56 (d, J ) 5.2 Hz, 2H), 9.36 (brs, 2H). 13C{1H} NMR
(C6D6): δ 0.8, 123.6, 124.0, 137.8, 138.5, 152.1, 152.5, 265.1. Anal.
Calcd for C18H28Cl3N2Si2Ta: C, 35.14; H, 4.59; N, 4.55. Found:
C, 35.17; H, 4.46; N, 4.31.
1
Kinetic Measurement by H NMR. All kinetic experiments
TaCl3(Me3SiCtCMe)(py)2 (7). To a toluene (15 mL) solution
of 1 (929 mg, 1.90 mmol) was added pyridine (340 µL, 3.80 mmol)
at room temperature. After stirring the mixture at room temperature
for 2 h, all volatiles were removed in vacuo and the resulting purple
solid was dissolved in dichloromethane (10 mL). After centrifuga-
tion, petroleum ether (20 mL) was slowly added to the supernatant
and placed in a -20 °C freezer for 2 days, during which purple
crystals were deposited. Removal of the supernatant by a syringe
and washing the crystals with petroleum ether afforded 691 mg
(1.24 mmol) in 65% yield.
were run in a sealed NMR tube with a total solution volume of
600 µL. The reactions were heated at a constant temperature in a
NMR probe in the JEOL LA400 spectrometer. A typical experi-
mental run for the alkyne exchange reaction of 2 with dipheny-
lacetylene is described as follows: complex 2 (19.7 mg, 40.2 µmol)
and diphenylacetylene (71.7 mg, 402 µmol) were placed in an NMR
tube using standard Schlenk techniques. Then 600 µL of C6D6 was
added via a syringe. The solution was quickly frozen in a dry ice-
MeOH bath, and the tube was flame sealed. The frozen solution
was warmed quickly in a water bath. The tube was placed in the
NMR probe. At specific intervals, 1H NMR spectra were recorded.
1
Mp: 170-175 °C (dec). IR (nujol/CsI): 1644, 303 cm-1. H
NMR (C6D6): δ 0.31 (s, 9H), 3.59 (s, 3H), 6.25 (t, J ) 6.6 Hz,
2H), 6.47 (t, J ) 7.0 Hz, 2H), 6.67 (t, J ) 7.7 Hz, 1H), 6.79 (t, J
) 7.6 Hz, 1H), 8.59 (d, J ) 5.2 Hz, 2H), 9.27 (brs, 2H). 13C{1H}
NMR (C6D6): δ 0.2, 28.9, 124.1, 138.5, 152.5, 250.6, 264.4. Anal.
Calcd for C16H22Cl3N2SiTa: C, 34.45; H, 3.98; N, 5.02. Found:
C, 33.98; H, 2.92; N, 4.96.
Treatment of Kinetic Data. An Eyring plot of ln(k/T) versus
1/T was made on a computer using a standard least-squares analysis.
The slope and the intercept of the line were obtained directly from
the computer.
X-ray Crystallographic Analysis. Crystallographic Data Col-
lections and Structure Determination. Data Collection. A
suitable crystal of each compound was mounted in a glass capillary
under an argon atmosphere. Data for complex 9 was collected by
a Rigaku AFC-7R diffractometer with graphite-monochromated Mo
KR (λ ) 0.71069 Å) radiation and a 12 kW rotating anode
generator. The incident beam collimator was 1.0 mm, and the crystal
to detector distance was 285 mm. Cell constants and an orientation
matrix for data collection, obtained from a least-squares refinement
using the setting angles of 25 carefully centered reflections,
corresponded to the cells with dimensions listed in Table 2, where
details of the data collection are summarized. The weak reflections
(I < 10σ(I)) were rescanned (maximum of 2 rescans) and the counts
were accumulated to ensure good counting statistics. Stationary
background counts were recorded on each side of the reflection.
The ratio of peak counting time to background counting time was
2:1. Three standard reflections were chosen and monitored every
150 reflections. For complexes 1, 2, 7, and 8 measurements were
made on a Rigaku RAIS-IV imaging plate diffractometer with
graphite-monochromated Mo KR (λ ) 0.71069 Å) radiation. The
incident beam collimator was 0.8 mm, and the crystal to detector
distance was 100.02 mm with the detector at the zero swing
position. Indexing was performed from four oscillations, which were
exposed for 4.0 min. The readout was obtained in the 0.100 mm
pixel mode. A total of 45 4.00° oscillation images were collected,
each being exposed for 4.0 min. Cell constants are listed in Table
2.
Data Reduction. An empirical absorption correction based on
azimuthal scans of several reflections was applied. The data were
corrected for Lorentz and polarization effects. The decays of
intensities of three representative reflections were -6.57% for 9,
and thus a linear correction factor was applied to the decay of these
observed data. Complexes 1, 2, 7, and 8 showed no decay.
Structure Determination and Refinement. All calculations
were performed using the TEXSAN crystallographic software
package, and illustrations were drawn with ORTEP. Crystal-
lographic calculations were performed on an SGI O2 workstation
at Venture Business Laboratory, Graduate School of Okayama
University. In the subsequent refinement, the function ∑w(|Fo| -
|Fc|)2 was minimized, where |Fo| and |Fc| are the observed and
calculated structure factor amplitudes, respectively. The agreement
indices are defined as R1 ) ∑|Fo| - |Fc|/∑|Fo| and wR2 )
[∑w(|Fo| - |Fc|)2/∑w(|Fo|)2]1/2. Atomic positional parameters for
the non-hydrogen atoms of all complexes are given in the
Supporting Information.
TaCl3(iPr3SiCtCMe)(dme) (8). Toluene (5 mL) was added to
TaCl5 (324 mg, 0.91 mmol) in a 20 mL Schlenk tube, and then
DME (2 mL) was slowly added to the resulting yellow suspension.
Zn powder (71 mg, 1.09 mmol) was added to the mixture in one
portion at room temperature. After stirring the mixture at room
temperature for 30 min, 1-(triisopropylsilyl)-1-propyne (217 µL,
0.91 mmol) was added and the suspension was stirred at 60 °C for
1 day. The resulting insoluble inorganic salts were removed by
centrifugation, and the reddish-brown supernatant was transferred
to a Schlenk tube. All volatiles were removed in vacuo, and the
resulting brown solid was dissolved in toluene (3 mL) and stirred
for 1 day. After centrifugation, the supernatant was concentrated
and hexane (5 mL) was slowly added to the supernatant. The
mixture was placed in a -20 °C freezer for 4 days, during which
reddish-brown crystals were deposited. Removal of the supernatant
by a syringe and washing the crystals with hexane afforded 691
mg (1.24 mmol) in 16% yield.
1
Mp: 118-122 °C (dec). IR (nujol/CsI): 1640, 311 cm-1. H
NMR (C6D6): δ 1.37 (d, J ) 7.6 Hz, 18H), 1.71 (sep, J ) 7.5 Hz,
3H), 3.12 (s, 3H), 3.14-3.16 (m, 4H), 3.43 (s, 3H), 3.62 (s, 3H).
13C{1H} NMR (C6D6): δ 13.4, 19.5, 30.1, 62.5, 67.8, 70.4, 75.6,
254.9, 260.8. Anal. Calcd for C16H34Cl3O2SiTa: C, 33.49; H, 5.97.
Found: C, 32.97; H, 5.66.
TaCl3(PhCtCCOOMe)(dme) (9). A toluene (20 mL) solution
of 1 (320 mg, 0.584 mmol) and PhCtCCOOMe (77 µL, 0.584
mmol) was heated at 50 °C for 1 day. The reaction mixture was
centrifuged, and the supernatant was transferred to a Schlenk tube.
All volatiles were removed under reduced pressure, and recrystal-
lization of the residue from DME (5 mL) and petroleum ether (10
mL) at -20 °C for 2 days gave 9 (271 mg, 0.504 mmol) as pale
yellow crystals in 86% yield.
1
Mp: 135-144 °C (dec). H NMR (CD2Cl2): δ 3.97 (s, 3H),
4.07 (s, 3H), 4.21 (s, 3H), 4.30-4.35 (m, 4H), 7.47 (t, J ) 7.3 Hz,
1H), 7.55 (t, J ) 7.3 Hz, 2H), 7.82 (d, J ) 7,1 Hz, 2H). 13C{1H}
NMR (CD2Cl2): δ 51.9, 63.4, 70.5, 71.6, 76.7, 128.5, 131.2, 133.0,
136.9, 228.3, 242.3. Anal. Calcd for C14H18Cl3O4Ta: C, 31.28; H,
3.37. Found: C, 31.29; H, 3.54.
TaCl3(PhCtCCONMe2)(py)2 (10). A toluene (30 mL) solution
of 6 (348 mg, 0.565 mmol) and PhCtCCONMe2 (97.9 mg, 0.565
mmol) was heated at 80 °C for 2 days. The yellow reaction mixture
was concentrated in vacuo, and the residue was extracted with
dichloromethane (17 mL). The extract was concentrated, and
petroleum ether (11 mL) was slowly added. Recrystallization at
Oshiki, Toshiyuki
