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Experimental Section
General procedures and materials
Further experimental details are given in the Supporting Informa-
tion.
Ethylene oligomerization
Oligomerization of ethylene was carried out in a 250 mL mechani-
cally stirred (1000 rpm) stainless steel pressure reactor equipped
with a heating/cooling jacket supplied by a thermostat controlled
by a thermocouple dipping into the polymerization mixture. A
valve controlled by a pressure transducer allowed for applying and
maintaining a constant ethylene pressure. The required flow of
ethylene, corresponding to ethylene consumed by polymerization,
was monitored by a mass flow meter and recorded digitally. Prior
to polymerization experiments, the reactor was heated under
vacuum to 908C for at least 60 min and then brought to the de-
sired temperature and backfilled with argon. A stock solution of
the catalyst precursor in methylene chloride was prepared daily
and stored in the glovebox at ꢀ308C. The amount required was
transferred into a syringe and removed from the glovebox. 100 mL
of toluene was transferred into the reactor through a cannula in
a slight argon stream before the catalyst solution was injected into
the reactor. After the desired reaction time, the reactor was first
cooled to 08C and then depressurized. The reaction was quenched
by adding 1 mL of methanol. The polymerization solution was im-
Unless stated otherwise, all manipulations of air- and moisture-sen-
sitive compounds were carried out under an inert gas atmosphere
by using standard glovebox and Schlenk techniques. Toluene was
distilled from sodium, methylene chloride and pentane were dis-
tilled from CaH , and THF and diethyl ether (Et O) were distilled
from sodium/benzophenone ketyl. Acetone p.a. and methyl acry-
late (MA) were degassed by repetitive freeze–thaw cycles and used
without further purification. DMSO and pyridine were purchased
2
2
from Aldrich and used without further purification. AgBF and
4
[40]
AgSbF6 were purchased from Aldrich. [PdMeCl(COD)] was pre-
pared according to a literature procedure. Ethylene (3.5 grade) was
purchased from Praxair. All deuterated solvents were supplied by
Eurisotop.
NMR spectra were recorded on a Varian Unity Inova 400 or
1
13
a Bruker Avance 400 spectrometer. H and C chemical shifts were
referenced to the solvent signals. The identity and purity of palladi-
1
13
um complexes and insertion products were established by H, C,
1
9
31
F, and P NMR spectroscopy, elemental analysis, and single-crystal
1
mediately studied by H NMR, GC, and GC-MS.
1
1
X-ray diffraction. NMR assignments were confirmed by H, H COSY,
1
1
1
13
1
13
19
H, H TOCSY, H{ C} HSQC, and H{ C} HMBC experiments. F and
3
1
P NMR chemical shifts were referenced to CFCl and 85% H PO ,
3
3
4
Reactions with ethylene and MA
respectively. Elemental analyses were performed on an Elementar
vario MICRO cube instrument. Gas chromatography (GC) was car-
ried out on a PerkinElmer Clarus 500 instrument with autosampler
and FID detection on a PerkinElmer Elite-5 (5% diphenyl-/95% di-
methylpolysiloxane) Series Capillary Columns (length: 30 m, inner
diameter: 0.25 mm, film thickness: 0.25 mm) by using helium as
Reactions with ethylene and MA were carried out in a 250 mL me-
chanically stirred (1000 rpm) stainless steel pressure reactor
equipped with a heating/cooling jacket supplied by a thermostat
controlled by a thermocouple dipping into the polymerization mix-
ture. A valve, controlled by a pressure transducer, allowed for ap-
plying and maintaining a constant ethylene pressure. Prior to olig-
omerization experiments, the reactor was heated under vacuum to
908C for at least 60 min, brought to the desired temperature, and
backfilled with argon. A solution of MA was prepared by dissolving
the desired amount of MA in toluene (50 mL total volume).
ꢀ1
carrier gas at a flow rate of 1.5 mLmin . The injector temperature
was 3008C. After injection the oven was kept isothermal at 408C
ꢀ
1
for 7 min, heated at 40 Kmin to 2808C, and kept isothermal at
808C for 3 min.
2
X-ray diffraction data were collected performed at 100 K on a STOE
IPDS-II diffractometer equipped with a graphite-monochromated
radiation source (l=0.71073 ꢁ) and an image-plate detection
system. A crystal mounted on a fine glass fiber with silicon grease
was employed. The selection, integration, and averaging procedure
of the measured reflex intensities, the determination of the unit-
cell dimensions by a least-squares fit of the 2q values, data reduc-
tion, LP correction, and space-group determination were per-
formed with the X-Area software package delivered with the dif-
2
00 mg of butylated hydroxytoluene (BHT) was added to this solu-
tion before it was cannula-transferred in a slight argon stream into
the reactor. A stock solution of the catalyst precursor in methylene
chloride was prepared daily and stored in the glovebox at ꢀ308C.
The amount required was transferred into a syringe, transferred
out of the glovebox, and the catalyst solution was injected into
the reactor. Ethylene pressure was applied, and after the desired
reaction time, the reactor was first cooled to 08C and then depres-
surized. The reaction was quenched by adding 1 mL of methanol,
and then three drops of polymerization solution was taken and im-
[41]
fractometer.
A semiempirical absorption correction was per-
formed. The structure was solved by direct methods (SHELXS-97),
completed by difference Fourier syntheses, and refined with full-
matrix least-squares techniques by using SHELXL-97 with minimiza-
1
mediately studied by H NMR, GC, and GC-MS.
À
Á
2
o
2
c
2 [42]
tion of w F ꢀ F
.
Following anisotropic refinement of all non-
Computational details
H atoms, ideal hydrogen positions were calculated in a isotropic
riding model. The weighted R factor (wR) and the goodness of fit S
All DFT geometry optimizations were performed at the GGA
[44]
[45]
2
BP86 level of theory with the Gaussian 09 package. The elec-
tronic configuration of the systems was described by the 6-31G
basis set for H, C, N, S, F, P and O, while for Pd we adopted the
quasi-relativistic LANL2DZ ECP effective core potential. All geo-
metries were characterized as minimum or transition state through
frequency calculations. The reported free energies were obtained
through single-point energy calculations on the BP86/6-31G geo-
metries by using the BP86 functional and the triple-z TZVP basis
set on main group atoms. Solvent effects were included with the
PCM model with toluene as solvent. In this BP86/TZVP electronic
were based on F ; the conventional R factor (R) was based on F. All
scattering factors and anomalous dispersion factors were provided
by the SHELXL-97 program. Hydrogen atoms were treated in
a riding model. Thermal ellipsoid representations were created
[46]
[43]
with ORTEP-3.
DIPP
DIPP
+
CCDC 973617 (Lb), 973618 ( 1-Cl), 973619 ( (1 -SbF )decomp.),
6
H
DIPP
CF3
[47]
9
77700
(
1-acetone), 977701
(
1-dmso), 973620 ( 1-pyr),
DIPP
CF3
9
73621 ( 1-pyr) and 973622 ( 1-pyr) contain the supplementa-
[48]
ry crystallographic data for this paper. These data can be obtained
Chem. Eur. J. 2015, 21, 2062 – 2075
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim