Dicyanodiphenylacetylene SilVer(I) Salts
J. Am. Chem. Soc., Vol. 119, No. 43, 1997 10411
Experimental Section
at 75 °C for 21 h produced an orange solution with a precipitate which
was presumed to be triethylammonium bromide. The mixture was
General Methods. Unless otherwise indicated, all starting materials
were obtained from commercial suppliers (Aldrich, J. T. Baker,
Eastman, EM Science, Fischer, Johnson-Matthey, Lancaster, and
Mallinckrodt) and were used without further purification. Dichlo-
romethane, ethyl acetate, and hexane were distilled prior to use.
2 2
cooled to room temperature and diluted with CH Cl (100 mL). The
resulting solution was concentrated in vacuo to yield crude product as
a dark red liquid with black and green solids. Column chromatography
(
15/1 hexane/ethyl acetate (v:v)) afforded 9 as a yellow liquid (4.39 g,
1
8
0% yield, 97% pure by GC): R
NMR (400 MHz, CDCl ) δ 7.62 (m, 1H), 7.53 (m, 2H), 7.39 (m, 1H),
.29 (s, 9H); C NMR (100 MHz, CDCl ) δ 132.5, 132.4, 132.2, 128.4,
f
0.36 (15/1 hexane/ethyl acetate); H
(Trimethylsilyl)acetylene (Farchan) was dried over anhydrous MgSO
4
3
and collected via vacuum transfer prior to use. Silver(I) triflate and
silver(I) hexafluoroantimonate were stored in a desiccator with Drierite
as the drying agent. Silver(I) perchlorate hydrate was stored in a
refrigerator at 3 °C. All atmosphere-sensitive reactions were conducted
under nitrogen using a Schlenk vacuum line. No precautions were taken
to exclude water or air during crystallization experiments or during
preparation of samples for ESI-MS. Analytical thin-layer chromatog-
raphy (TLC) was performed on KIESELGEL F-254 precoated silica
gel plates. Visualization was accomplished with a UV light. Flash
chromatography was carried out with Silica Gel 60 (230-400 mesh)
from EM Science.
13
0
1
3
26.9, 117.3, 115.7, 102.1, 100.5, -0.4; LRMS (EI) m/z 199 (7), 185
+
(17), 184 (100), 154 (14); HRMS (EI) calcd for C12
H
13NSi 199.0817,
found 199.0823.
2
,3′-Dicyanodiphenylacetylene (1). To a solution of 2-[(trimeth-
ylsilyl)ethynyl]benzonitrile (9; 4.15 g, 20.82 mmol) in CH Cl (15 mL)
and MeOH (30 mL) was added a trace of K CO . The brown mixture
2
2
2
3
was degassed and back-filled with nitrogen three times and stirred under
nitrogen at room temperature for 55 min, resulting in a yellow mixture.
The conversion of 9 to 2-ethynylbenzonitrile was confirmed by GC
and GC/MS (LRMS (EI) showed the desired molecular ion of m/z 127
1H and 13C NMR spectra were recorded on a Varian Unity 400
spectrometer. Chemical shifts were recorded in parts per million (δ),
and splitting patterns were designated as s (singlet) or m (multiplet).
+
for C H
9 5
N ). The terminal acetylene was not isolated. Next, in a dry,
heavy-walled tube sealed with a Teflon screw cap were placed
-bromobenzonitrile (2.32 g, 12.72 mmol), Pd(dba) (0.13 g, 0.22
mmol), CuI (0.05 g, 0.26 mmol), Ph P (0.31 g, 1.18 mmol), and
3
2
1
13
Chloroform (δ 7.26 for H, δ 77.0 for C) was used as an internal
standard for chloroform-d. Gas chromatography (GC) was performed
on a Hewlett-Packard HP-5890 Series II gas chromatograph equipped
with a 12.5 m × 0.2 m × 0.5 µm HP-1 methyl silicone column and
fitted with a flame ionization detector using helium carrier gas at 30
mL/min. Low-resolution electron impact mass spectra were obtained
using a Hewlett-Packard 5890 gas chromatograph combined with a 5970
Series mass-selective detector equipped with a 30 m HP-1 capillary
column operating at 70 eV. High-resolution electron impact mass
spectra were obtained on a Finnigan-MAT 731 spectrometer operating
at 70 eV. Elemental analyses were performed by the University of
Illinois Microanalytical Service Laboratory by combustion analysis on
a Leeman Labs, Inc., Model CE440 Elemental Analyzer.
3
triethylamine (50 mL). This mixture was degassed and back-filled with
nitrogen three times and left under nitrogen at room temperature. A
2 2
portion of the CH Cl /MeOH solution of 2-ethynylbenzonitrile (22 mL,
1
.29 g (10.15 mmol) of 2-ethynylbenzonitrile assuming quantitative
conversion from 9) was then added via syringe. The tube was sealed
with the Teflon screw cap and placed in an oil bath. Heating at 77 °C
for 21 h produced a brown solution with a precipitate which was
presumed to be triethylammonium bromide. This mixture was cooled
to room temperature, dissolved in CH
in vacuo to yield crude product as a brown solid. Column chroma-
tography (CH Cl ) afforded 1 as a yellow solid. Recrystallization from
/1 benzene/hexane (v:v) afforded pure 1 as a white solid (1.42 g, 61%
2 2
Cl (100 mL), and concentrated
2
2
1
Crystallization with silver(I) triflate and silver(I) hexafluoro-
antimonate was accomplished by heating and slow cooling in a
programmable oven equipped with a Thermolyne temperature controller.
All crystals were stored in the dark until the collection of X-ray data.
For X-ray analysis, all crystals were mounted using Paratone-N oil
1
yield, 99% pure by GC): R
f 2 2 3
0.44 (CH Cl ); H NMR (400 MHz, CDCl )
δ 7.86 (m, 1H), 7.82 (m, 1H), 7.70 (m, 1H), 7.63 (m, 3H), 7.49 (m,
13
2
1
8
3
H); C NMR (100 MHz, CDCl ) δ 136.0, 135.0, 132.7, 132.5, 132.3,
32.2, 129.4, 129.0, 126.1, 123.6, 117.8, 117.3, 115.5, 113.0, 93.0,
7.6; LRMS (EI) m/z 229 (18), 228 (100), 227 (12), 201 (11); HRMS
EI) calcd for C16
(Exxon).
+
(
H
8
N
2
228.0687, found 228.0687. Anal. Calcd for
X-ray data were collected on a Siemens SMART system equipped
16 8 2
C H N : C, 84.19; H, 3.53; N, 12.28. Found: C, 83.80; H, 3.55; N,
with a CCD detector at -75 °C using Mo KR (λ ) 0.710 73 Å) as the
incident radiation. The intensity data were reduced by profile analysis
and corrected for Lorentz, polarization, and absorption effects. Cell
parameters and atomic coordinates were tested for higher symmetry
12.17.
,2′-Dicyanodiphenylacetylene (2). By following the procedure
used to prepare 2,3′-dicyanodiphenylacetylene (1), 2-bromobenzonitrile
1.43 g, 7.86 mmol), Pd(dba) (0.08 g, 0.14 mmol), CuI (0.03 g, 0.16
mmol), Ph P (0.19 g, 0.72 mmol), and triethylamine (30 mL) were
2
(
2
1
2
using the PLATON program. Structure solutions were obtained by
direct methods and were refined using full-matrix least-squares on all
3
combined in a dry, heavy-walled tube sealed with a Teflon screw cap.
A solution of 2-ethynylbenzonitrile (0.89 g, 7.00 mmol (assuming
quantitative conversion from trimethylsilyl-protected precursor 9)) in
CH Cl (10 mL) and MeOH (20 mL) was added to the mixture via
2
13
o
reflections, based on F , with SHELXTL.
Solutions for electrospray ionization mass spectrometry (ESI-MS)
were prepared using reagent grade acetone or acetonitrile. Vials were
lined with Teflon film prior to sealing them with a screw cap. ESI-
MS was performed on a Fisons Instruments VG QUATTRO spectrom-
eter. For the ESI-MS data, masses and intensities were compared to
those calculated using the Isotope Pattern Calculator program (ver. 1.6.5,
2
2
syringe. Heating at 80 °C for 20 h produced a brown solution with a
precipitate which was presumed to be triethylammonium bromide. The
mixture was cooled to room temperature, dissolved in CH Cl (100
2
2
mL), and concentrated in vacuo to afford crude product as a brown
1
4
Macintosh).
CAUTION: One of the crystallization procedures involves
AgClO ‚xH
O (x ∼ 1), which is an oxidizer.
-[(Trimethylsilyl)ethynyl]benzonitrile (9). 2-Bromobenzonitrile
5.01 g, 27.52 mmol), Pd(dba) (0.32 g, 0.56 mmol), CuI (0.11 g, 0.58
mmol), and Ph P (0.72 g, 2.75 mmol) were combined with triethylamine
100 mL) in a dry, heavy-walled tube sealed with a Teflon screw cap.
solid. Column chromatography (4/1 CH Cl /hexane (v:v)) afforded 2
2
2
as a yellow solid. Recrystallization from 1/1 benzene/hexane (v:v)
4
2
afforded pure 2 as a light yellow needles (0.95 g, 59% yield, 99%
1
2
pure by GC): R
f
0.20 (4/1 CH
2
Cl
2
/hexane); H NMR (400 MHz, CDCl
3
)
1
3
(
2
δ 7.75 (m, 2H), 7.70 (m, 2H), 7.61 (m, 2H), 7.48 (m, 2H); C NMR
(100 MHz, CDCl ) δ 132.9, 132.7, 132.5, 129.2, 125.8, 117.2, 115.2,
3
3
(
91.2; LRMS (EI) m/z 229 (18), 228 (100), 227 (13), 201 (14); HRMS
+
The resulting mixture was degassed and back-filled with nitrogen three
times and left under nitrogen at room temperature. Dry (trimethylsilyl)-
acetylene (6.0 mL, 42.46 mmol) was then added via syringe. The tube
was sealed with the Teflon screw cap and placed in an oil bath. Heating
(EI) calcd for C16
H
8
N
2
228.0687, found 228.0687. Anal. Calcd for
16 8 2
C H N : C, 84.19; H, 3.53; N, 12.28. Found: C, 84.26; H, 3.32; N,
12.28.
4-[(Trimethylsilyl)ethynyl]benzonitrile (10). By following the
procedure used to prepare 2-[(trimethylsilyl)ethynyl]benzonitrile (9),
(
12) Spek, A. L. J. Appl. Crystallogr. 1988, 21, 578-579.
4
2
-bromobenzonitrile (5.01 g, 27.52 mmol), Pd(dba) (0.31 g, 0.54
(13) The SHELXTL X-ray structure refinement package consists of
mmol), CuI (0.10 g, 0.53 mmol), Ph P (0.72 g, 2.75 mmol), triethyl-
3
SAINT Version 4, SHELXTL Version 5, and SMART Version 4 and is
marketed by Siemens Industrial Automation, Inc., Madison, WI.
amine (100 mL), and trimethylsilylacetylene (6.0 mL, 42.46 mmol)
were combined in a dry, heavy-walled tube sealed with a Teflon screw
cap. Heating for 16 h at 75 °C produced an orange solution with a
(14) Isotope Pattern Calculator, Version 1.6.5: Arnold, L. University of
Waikato, Hamilton, New Zealand, 1990.