Article
Organometallics, Vol. 28, No. 13, 2009 3951
After 1 h of stirring, the solvent was removed under vacuum.
The resulting yellow solid was dissolved in benzene and filtered
through Celite. The volatile material was removed in vacuo, and
the resulting solid was washed with 5 mL of pentane three times
to give a yellow powder in 92% yield (0.823 g, 1.40 mmol). 1H
NMR (C6D6): δ 9.30 (d JHH=5.2 Hz, 1H, ArH), 7.66
(d JHH=6.0 Hz, 2H, ArH), 7.53 (d JHH=6.0 Hz, 2H, ArH),
7.30-7.10 (ov m with benzene-d6, 7H, ArH), 6.62 (s, 1H,
ArH), 6.42 (t JHH=6.0 Hz, 1H, ArH), 5.94 (t JHH=6.0 Hz,
1H, ArH), 1.77 (v q JPtH=32.5 Hz, 6H, S(CH3)2). 13C{1H}
NMR: δ 158.2, 147.5, 145.8, 137.6, 137.4, 131.7, 128.9, 128.4,
128.3, 126.9, 126.6, 117.2, 116.9, 114.3, 21.3. Anal. Calcd (%)
for C23H21ClN4Pt: C, 46.98; H, 3.60; N, 4.76. Found: C,
46.45; H, 3.82; N, 4.33.
(PyPyr)Pt(H)2SiEt3 (3). To a 5 mL solution of (PyPyr)Pt
(C2H4)Cl (0.100 g, 0.18 mmol) in benzene was added HSiEt3
(0.084 g, 0.72 mmol). The reaction mixture was stirred for 12 h,
and then the volatilematerial was removed invacuo. The resulting
red solid was dissolved in pentane and crystallized by slow
evaporation to give red plates in 95% yield (0.104 g, 0.17 mmol).
1H NMR (C6D6): δ 8.07 (d JHH=5.0 Hz, 1H, ArH), 7.97 (d
JHH=7.0 Hz, 2H, ArH), 7.55 (d JHH=7.0 Hz, 2H, ArH), 7.36-
7.27 (ov m, 6H, ArH), 7.14 (t JHH=7.5 Hz, 1H, ArH), 6.98 (s, 1H,
ArH), 6.51 (t JHH=7.0 Hz, 1H, ArH), 5.97 (t JHH=6.0 Hz, 1H,
ArH), 0.97 (t JHH=4.5 Hz, 9H, SiCH2CH3), 0.66 (t JHH=4.5 Hz,
6H, SiCH2CH3), -15.17 (d JHH=7.5 Hz, JPtH=968 Hz, 1H,
PtH), -16.97 (d JHH=7.5 Hz, JPtH=1114 Hz, 1H, PtH). 1H, 29Si
{1H} HMBC NMR: δ 44.2 (s JPtSi=704.5 Hz). 13C{1H} NMR:
δ158.0, 152.6, 146.8, 138.5, 138.2, 137.0, 132.9, 129.6, 129.0, 128.4,
127.9, 127.5, 126.5, 126.2, 118.4, 118.2, 113.9, 10.9, 7.6. Anal.
Calcd (%) for C27H32N2PtSi: C, 53.36; H, 5.31; N, 4.61. Found: C,
53.08; H, 5.24; N, 4.46. IR (cm-1): νPtH 2221, 2254.
(PyPyr)Pt(H)2SiEtMe2 (4). To a 5 mL solution of (PyPyr)Pt
(C2H4)Cl (0.100 g, 0.18 mmol) in benzene was added HSiEtMe2
(0.064 g, 0.73 mmol). The reaction mixture was stirred for 12 h,
and then the volatile material was removed in vacuo. The
resulting red solid was dissolved in THF/pentane (1:1), and
the mixture was concentrated to 1 mL. Slow evaporation of the
reaction mixture gave red plates in 94% yield (0.098 g, 0.17
mmol). 1H NMR (C6D6): δ 10.05 (br s, 1H, ArH), 8.34 (d
JHH=5.0 Hz, 1H, ArH), 7.96 (d JHH=7.2 Hz, 2H, ArH), 7.56 (d
JHH=6.8 Hz, 2H, ArH), 7.39 (d JHH=5.0 Hz, 2H, ArH), 7.26
(ov m, 5H, ArH), 6.81 (t JHH=7.5 Hz, 1H, ArH), 6.63 (s, 1H,
ArH), 6.46 (t JHH=7.5 Hz, 1H, ArH), 0.76 (t JHH=6.5 Hz, 3H,
SiCH2CH3), 0.67 (t JHH=6.5 Hz, 2H, SiCH2CH3), 0.22 (s
132.3, 129.5, 128.7, 128.5, 128.2, 126.7, 126.3, 125.5, 123.8,
118.7, 117.7, 113.5, 110.4, 34.5, 11.2, 8.4. Anal. Calcd (%) for
C34H42N4PtSi: C, 55.95; H, 5.80; N, 7.68. Found: C, 56.28; H,
5.68; N, 7.76. IR (cm-1): νPtH 2206, 2262.
(PyPyr)Pt(PiPr3)H (6). To a 5 mL solution of (PyPyr)Pt-
(H)2SiEt3 (0.100 g, 0.164 mmol) in benzene was added PiPr3
(0.0265 g, 0.165 mmol). The reaction mixture was stirred for 1 h,
and then the volatile material was removed in vacuo. The
resulting brown solid was dissolved in 1 mL of THF, and
pentane was allowed to diffuse into the solution. Brown blocks
1
were isolated in 72% yield (0.0770 g, 0.118 mmol). H NMR
(C6D6): δ 8.12 (d JHH = 7.5 Hz, 2H, ArH), 7.62 (d JHH
7.5 Hz, 2H, ArH), 7.51 (d JHH=8.0 Hz, 1H, ArH), 7.35-7.20
(ov m, 5H, ArH), 6.83 (s, 1H, ArH), 6.60 (t JHH=7.5 Hz, 1H,
ArH), 6.15 (t JHH=6.0 Hz, 1H, ArH), 1.78 (m, 3H, PCH), 0.99
(m, 18H, PCHCH3), -19.64 (d JPH=28.5 Hz, JPtH=1208 Hz,
1H, PtH). 31P{1H} NMR: 41.2 (s JPPt = 3688 Hz). 13C{1H}
NMR: δ 159.5, 150.2, 148.7, 139.6, 137.5, 135.9, 131.6, 129.2,
128.7, 128.3, 126.9, 126.0, 125.6, 123.8, 118.8, 116.8, 113.7, 24.2
(JCP =32.0 Hz), 19.5. Anal. Calcd (%) for C30H37N2PPt: C,
55.29; H, 5.72; N, 4.30. Found: C, 54.89; H, 5.44; N, 4.09.
(PyPyr)Pt(PPh3)H (7). To a 5 mL solution of (PyPyr)Pt-
(H)2SiEt3 (0.020 g, 0.033 mmol) in benzene was added PPh3
(0.0085 g, 0.033 mmol). The reaction mixture was allowed to stir
for 1 h, and then the volatile material was removed in vacuo. The
brown solid was dissolved in 1 mL of THF, and pentane was
allowed to diffuse into the solution. Brown blocks were isolated in
90% yield (0.023 g, 0.031 mmol). 1H NMR (C6D6): δ 8.21
(d JHH=7.5 Hz, 2H, ArH), 7.65 (ov m, 7H, ArH), 7.47 (ov m,
3H, ArH), 7.23 (ov m, 3H, ArH), 6.92 (ov m, 13H, ArH), 6.49
(t JHH = 7.5 Hz, 1H, ArH), 5.72 (t JHH = 6.0 Hz, 1H, ArH),
-17.47 (d JPH=29.5 Hz, JPtH=1184 Hz, 1H, PtH). 31P{1H} NMR:
21.9 (s JPPt=1918 Hz). 13C{1H} NMR: δ 148.8, 139.2, 137.3, 136.0,
135.5, 135.0, 134.1 (JCP=15.0 Hz), 129.8 (JCP=7.5 Hz), 129.5,
129.2, 128.5, 127.4, 126.7, 125.7, 123.8, 120.1, 119.2, 118.7, 116.8,
113.8, 110.5. Anal. Calcd (%) for C39H31N2PPt: C, 62.15; H, 4.15;
N, 3.72. Found: C, 62.29; H, 4.56; N, 3.06.
=
General Procedure for Catalytic Runs. Reactions were con-
ducted in 5 mm Wilmad NMR tubes equipped with a J. Young
Teflon-valve seal, which were heated in temperature-controlled
oil baths. Samples were prepared in the drybox by dissolving the
catalyst, silane, and alkyne or olefin in C6D6. Gases were
condensed on a Schlenk line using a volumetric gas bulb.
1
Reaction progress was monitored by H NMR spectroscopy.
Product identities and yields were determined by 1H NMR
spectroscopy and GC-MS relative to an internal standard.
Kinetic Measurements. Reactions were monitored by 1H
NMR spectroscopy, on a Bruker AV-500 spectrometer, using
5 mm Wilmad NMR tubes fitted with septa. The samples were
prepared by dissolution of 3 in 1 mL of C6D6 that was added to
the NMR tube, which was sealed. The NMR tube was then
cooled to 0 °C in an ice bath. To this cooled solution was added
via a syringe HSiEtMe2. The NMR tube was quickly placed in
the probe, which was preheated to 50 °C. The probe temperature
was calibrated using a neat methanol sample prior to the
experiment and was monitored throughout the experiment with
a thermocouple. Single-scan spectra were obtained using an
automated acquisition program that was started immediately
after placing the sample in the probe, and the peaks were
integrated relative to the intensity of a known concentration
of a hexamethylbenzene standard. Rate constants were obtained
by nonweighted linear least-squares fit of the integrated first-
order rate law.
JSiH=8.0 Hz, JPtH=16.4 Hz, 6H, SiCH3), -15.36 (d JHH
=
7.2 Hz, JPtH=1000 Hz, 1H, PtH), -16.89 (d JHH=7.2 Hz,
JPtH=1154 Hz, 1H, PtH). 1H, 29Si{1H} HMBC NMR: δ 29.2.
13C{1H} NMR: δ 152.6, 150.7, 148.8, 138.5, 137.6, 135.5, 132.7,
131.9, 128.8, 128.5, 127.1, 126.4, 123.8, 120.1, 119.2, 118.0,
110.4, 7.75, 4.56, 1.00. Anal. Calcd (%) for C25H26N2PtSi: C,
51.98; H, 4.54; N, 4.85. Found: C, 52.37; H, 4.83; N, 4.80.
IR (cm-1): νPtH 2220, 2252.
(PyPyr)Pt(H)2SiEt3(DMAP) (5). To a 5 mL solution of
(PyPyr)Pt(H)2SiEt3 (0.080 g, 0.13 mmol) in benzene was added
DMAP (0.017 g, 0.12 mmol). The reaction mixture was stirred
for 1 h, and then the volatile material was removed in vacuo. The
resulting brown solid was dissolved in 1 mL of THF, and
pentane was allowed to diffuse into the reaction mixture. Brown
plates were isolated in 90% yield (0.087 g, 0.12 mmol). 1H NMR
(C6D6): δ 8.28 (d JHH=5.0 Hz, 2H, ArH), 8.13 (d JHH=7.2 Hz,
2H, ArH), 7.81 (d JHH=7.2 Hz, 2H, ArH), 7.54 (d JHH=7.2 Hz,
1H, ArH), 7.36-7.27 (ov m, 6H, ArH), 7.09 (d JHH=7.5 Hz,
1H, ArH), 6.95 (t JHH=6.4 Hz, 1H, ArH), 6.61 (s, 1H, ArH),
5.98 (t JHH=6.4 Hz, 1H, ArH), 5.89 (d JHH=5.0 Hz, 2H, ArH),
2.03 (s, 6H, NCH3), 0.98 (t JHH=5.4 Hz, 9H, SiCH2CH3), 0.80
(t JHH=5.4 Hz, 6H, SiCH2CH3), -16.99 (d JHH=6.4 Hz,
X-ray Structure Determination. The X-ray analyses of 2 and 3
were carried out at UC Berkeley CHEXRAY crystallographic
facility. Measurements were made on a Bruker APEX CCD
area detector with graphite-monochromated Mo Ka radi-
˚
JPtH=1150 Hz, 1H, PtH), -18.10 (d JHH=6.4 Hz, JPtH
=
ation (λ=0.71073 A). Data were integrated by the program
SAINT and analyzed for agreement using XPREP. Empi-
rical absorption corrections were made using SADABS. The
1200 Hz, 1H, PtH). 1H, 29Si{1H} HMBC NMR: δ 9.8. 13C
{1H} NMR: δ 157.7, 152.0, 148.7, 145.5, 139.7, 136.8, 135.8,