Organometallics
Article
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K, CD2Cl2): δ 1.02−1.12 ppm (m, 6H, 2 × CH3 of Pr), 1.20−1.30
139.0 (both s, aryl C-H), 159.6 (s, aryl Cq), carbon adjacent to boron
not observed. 11B{1H} NMR (128.4 MHz, 298 K, CD2Cl2): δ +2.6
ppm (s, br, C6H4BF3Ni). 19F NMR (376.6 MHz, 298 K, CD2Cl2): δ
−173.8 ppm (s, br, C6H4BF3Ni). 31P{1H} NMR (162.0 MHz, 298 K,
CD2Cl2): δ +18.5 ppm (q, PiPr2(C6H4BF3), 4JPF = 6 Hz). Anal. Calcd
for C25H32BF3NNiP: C, 59.58; H, 6.40; N, 2.78. Found: C, 59.74; H,
6.58; N, 2.50.
(m, 6H, 2 × CH3 of iPr), 2.14 (m, 2H, 2 × CH of iPr), 6.50−6.60 (m,
3H, aryl C-H of Ni(C6H5)), 7.10 (d, 2H, aryl C-H of Ni(C6H5), 3JHH
=
3
7 Hz), 7.26 (t, 1H, aryl C-H, JHH = 8 Hz), 7.30 (m, 7H, aryl C-H),
3
7.41−7.51 (m, 10H, aryl C-H), 7.56 (d, 1H, aryl C-H, JHH = 8 Hz).
13C{1H} NMR (100.6 MHz, 298 K, CD2Cl2): δ 18.4 ppm (s, CH3 of
iPr), 19.0 (d, CH3 of Pr, JCP = 3 Hz), 24.9 (d, CH of Pr JCP = 18
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Attempted Generation of [κ2(P,F)-i‑PrNiPh(NCCD3)(2,6-luti-
dine)] (3·NCCD3). A J. Young NMR tube was charged with 3 (0.010
g, 0.020 mmol), and CD3CN (0.6 mL) was added in a glovebox.
According to NMR data, 50% of the starting complex was consumed
with the release of free lutidine. No signals of the noncoordinated BF3
group were observed in the 19F NMR spectrum of the reaction
mixture.
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Hz), 25.0 (d, CH of Pr, JCP = 18 Hz), 122.8 (t, aryl C-H, JCP = 3
3
Hz), 126.8 (s, aryl C-H), 127.2 (d, aryl C-H, JCP = 4 Hz), 128.5 (d,
aryl C-H, 2JCP = 9 Hz), 128.7 (d, aryl C-H, 2JCP = 9 Hz), 128.9 (d of d,
aryl C-H, 3JCP = 8 Hz, 4JCP = 2.0 Hz), 129.5 (d, aryl Cq, 1JCP = 10 Hz),
129.8 (d, aryl Cq, 1JCP = 10 Hz), 129.9 (s, aryl C-H), 130.8 (d, aryl C-
4
4
H), JCP = 2 Hz), 132.5 (m, aryl C-H), 131.1 (d, aryl C-H, JCP = 2
3
4
Hz), 134.7 (d of d, aryl C-H, JCP = 8 Hz, JCP = 3 Hz), 138.2 (t, aryl
[κ2(P,F)-i‑PrNi(allyl)] (4). A 50 mL round-bottomed flask was
charged with a solid mixture of [(allyl)NiBr]2 (0.070 g, 0.39 mmol)
and 1 (0.117 g, 0.39 mmol). Dry chlorobenzene (10 mL) was added
via syringe, and the reaction mixture was stirred for 1 h at room
temperature. The resulting brown reaction mixture was filtered, and
the filtrate was evaporated under vacuum. The residue was extracted
with toluene (3 × 5 mL) and concentrated under vacuum. Hexane was
layered over the solution; a yellow precipitate was obtained overnight
at −30 °C. The precipitate was separated from the solution by
decantation, washed with hexane, and dried under vacuum. Yield:
0.105 g (75%). (Slow decomposition of the compound in solution
results in the formation of unidentified paramagnetic impurities, which
C-H, JCP = 3 Hz), carbon adjacent to boron not observed. 11B{1H}
4
NMR (128.4 MHz, 298 K, CD2Cl2): δ +3.9 ppm (s, br, C6H4BF3Ni).
19F NMR (376.6 MHz, 298 K, CD2Cl2): δ −178.9 ppm (s, br,
C6H4BF32Ni). 31P{1H} NMR (162 MHz, 298 K, CD2Cl2): δ 13.2 (d of
q, PPh3, JPP = 257 Hz, JPF = 16 Hz), 11.3 (d of q, PiPr2(C6H4BF3),
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4
2 JP P
=
257 Hz, JP F
=
11 Hz). Anal. Calcd for
C36H38BF3NiP2·0.1CH2Cl2: C, 64.94; H, 5.77. Found: C, 64.98; H,
6.00.
[κ2(P,F)-i‑PrNiPh(NCCH3)(PPh3)] (2·NCCH3). A solution of com-
plex 2 (0.030 g, 0.045 mmol) in acetonitrile (1 mL) was layered with a
mixture of Et2O and toluene (1/1). Yellow crystals were obtained after
3 days at −30 °C. Yield: 0.010 g (∼30%). Quantitative conversion of 2
into [κ2(P,F)-i‑PrNiPh(NCCD3)(PPh3)] was observed by NMR
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results in the overall broadness of all signals in NMR spectra.) H
NMR (400 MHz, 298 K, CD2Cl2): δ 1.17−1.32 ppm (m, 12H, 4 ×
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spectroscopy in CD3CN. H NMR (400 MHz, 298 K, CD3CN): δ
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CH3 of Pr), 2.30 (m, 2H, 2 × CH of Pr), 2.68 (s, br, 2H,
CH2CHCH2), 3.52 (s, br 2H, CH2CHCH2), 5.74 (m, 1H,
CH2CHCH2), 7.34 (m, 1H, aryl C-H of C6H4BF3), 7.43 (m, 1H,
aryl C-H of C6H4BF3), 7.71 (m, 1H, aryl C-H of C6H4BF3). 13C{1H}
NMR (100.6 MHz, 298 K, CD2Cl2): δ 18.8, 19.4 ppm (both s, br, CH3
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1.02 ppm (m, br, 6H, 2 × CH3 of Pr), 1.18 (m, br, 6H, 2 × CH3 of
iPr), 2.15 (s, br, 2H, 2 × CH of Pr), 6.53 (s, br, 3H, aryl C-H of
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Ni(C6H5)), 7.12 (t, 1H, aryl C−H, 3JHH = 8 Hz), 7.20 (s, br, 2H, aryl
C-H of Ni(C6H5)), 7.24−7.38 (m, 8H, aryl C-H), 7.38−7.52 (m, 9H,
aryl C-H), 7.78 (d, 1H, aryl C−H, 3JHH = 8 Hz). 13C{1H} NMR (100.6
MHz, 298 K, CD3CN): δ 19.1, 20.5 ppm (both s, CH3 of iPr), 24.4 (d,
CH of iPr, 1JCP = 21 Hz), 122.6 (s), 125.9 (d, 3JCP = 5 Hz), 127.3 (s),
129.2 (s), 129.4 (bs), 131.0 (s), 131.2 (s), 135.12 (bs), 136.0 (m),
139.2 (s), all aryl C-H and Cq), carbon adjacent to boron not observed.
11B{1H} NMR (128.4 MHz, 298 K, CD3CN): δ 4.1 ppm (s, br,
C6H4BF3Ni). 19F NMR (376.6 MHz, 298 K, CD3CN): δ −137.6 ppm
(s, br, C6H4BF3Ni). 31P{1H} NMR (162.0 MHz, 298 K, CD3CN): δ
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of Pr), 25.7 (d, br, CH of Pr, JCP = 26 Hz), 113.8, 127.2, 127.4,
130.2, 131.5, 133.2 (all s, br, aryl C-H and aryl Cq). Several resonances
could not be located due to the broadness of signals. 11B{1H} NMR
(128.4 MHz, 298 K, CD2Cl2): δ +3.7 ppm (s, br, C6H4BF3Ni). 19F
NMR (376.6 MHz, 298 K, CD2Cl2): δ −186.1 ppm (s, br,
C6H4BF3Ni). 31P{1H} NMR (162 MHz, 298 K, CD2Cl2): δ 29.0 (s,
br, PiPr2(C6H4BF3)). Anal. Calcd for C15H23BF3NiP·0.2C6H5Cl: C,
50.76; H, 6.31. Found: C, 50.62; H, 6.41.
26.3 ppm (d, PPh3, JPP = 251 Hz), 21.3 (d, PiPr2(C6H4BF3), JPP
=
2
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Generation of [κ2(P,F)-i‑PrNi(allyl)(NCCD3] (4·NCCD3). A J.
Young NMR tube was charged with 4 (0.010 g, 0.028 mmol), and
CD3CN (0.6 mL) was added in a glovebox. Full conversion of 4 into
251 Hz). Anal. Calcd for C38H41BF3NNiP2: C, 65.18; H, 5.90; N, 2.00.
Found: C, 63.00; H, 5.80; N, 2.21 (complex 2·NCCH3 contains
cocrystallized solvent molecules in the solid state, confirmed by X-ray
analysis).
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4·NCCD3 was observed by NMR spectroscopy. H NMR (400 MHz,
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298 K, CD3CN): δ 0.95−1.08 ppm (dd, 6H, 2 × CH3 of Pr, JPH
=
=
[κ2(P,F)-i‑PrNiPh(2,6-lutidine)] (3). A 5 mL round-bottomed flask
was charged with a solid mixture of NiClPh(tmeda) (0.067 g, 0.23
mmol) and 1 (0.070 g, 0.23 mmol). Dry 2,6-lutidine (1 mL) was
added via syringe, and the reaction mixture was stirred for 1 h at room
temperature. The resulting dark orange solution was evaporated under
vacuum, and the residue was extracted with CH2Cl2 (2 × 5 mL). The
extracted fractions were combined and concentrated under vacuum. A
few drops of 2,6-lutidine were added to the solution, followed by
layering with hexane. Yellow-red crystals were obtained at −30 °C
after a few days. The crystals were separated from the solution by
decantation, washed with hexane, and dried under vacuum. Yield:
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13.3 Hz, JHH = 6.8 Hz), 1.12−1.22 (dd, 6H, 2 × CH3 of Pr, JPH
15.9 Hz, 3JHH = 6.8 Hz), 2.43 (m, 2H, 2 × CH of iPr), 2.58 (s, br, 2H,
CH2CHCH2), 3.60 (s, br 2H, CH2CHCH2), 5.49 (m, 1H,
CH2CHCH2), 7.20 (m, 1H, aryl C-H of C6H4BF3), 7.32 (m, 2H,
aryl C-H of C6H4BF3), 7.72 (m, 1H, aryl C-H of C6H4BF3). 13C{1H}
NMR (100.6 MHz, 298 K, CD3CN): δ 18.7 ppm (s, CH3 of iPr), 19.2
(d, CH3 of iPr, 2JPC = 5.5 Hz), 24.3 (d, br, CH of iPr, 1JCP = 22.5 Hz),
113.2 (s), 125.7 (d, J = 6.0 Hz), 127.4 (d, J = 35.4 Hz), 129.5 (d, J =
2.2 Hz), 131.4 (s), 136.3 (d, J = 12.4 Hz). 11B{1H} NMR (128.4 MHz,
298 K, CD3CN): δ +3.9 ppm (q, br, C6H4BF3Ni, JBF = 55 Hz). 19F
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NMR (376.6 MHz, 298 K, CD3CN): δ −137.3 ppm (s, br, C6H4BF3).
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0.050 g (43%). H NMR (400 MHz, 298 K, CD2Cl2): δ 1.03 ppm (d
31P{1H} NMR (162 MHz, 298 K, CD3CN): δ 33.6 (q, br,
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PiPr2(C6H4BF3), J = 14.1 Hz).
of d, 6H, 2 × CH3 of Pr, JPH = 15 Hz, J\HH = 7 Hz), 1.37 (d of d,
6H, 2 × CH3 of iPr, 3JPH = 15 Hz, 3JHH = 7 Hz), 2.49 (m, 2H, 2 × CH
of iPr), 4.00 (s, 6H, 2 × CH3 of lutidine), 6.72 (m, 1H, aryl C-H), 6.78
Oligomerization of Ethylene. Method 1 (NMR Scale Reactions).
A J. Young NMR tube was charged with precatalyst (4.5 μmol), and
CD2Cl2 (0.6 mL) was added in a glovebox. The NMR tube was then
attached to a high-vacuum line and degassed via repeated freeze−
pump−thaw cycles, before the admission of ethylene at 1 atm pressure.
The reaction was monitored by NMR spectroscopy.
Method 2. In a 100 mL round-bottom flask was added toluene (30
mL) followed by addition of 300 μL of a precatalyst solution in
CH2Cl2 (1.5 × 10−2 M). The flask was degassed via repeated freeze−
pump−thaw cycles. In the flask was added ethylene at 1 atm pressure.
The pressure of ethylene was maintained during the reaction. The
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(m, 2H, aryl C-H), 7.08 (d, 2H, aryl C-H, JHH = 8 Hz), 7.31 (t, br,
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aryl C-H, 1H, JHH = 8 Hz), 7.42 (t, br, aryl C-H, 1H, JHH = 8 Hz),
7.51−7.45 (m, 3H, aryl C-H), 7.54 (t, 1H, aryl C-H, 3JHH = 8 Hz), 7.68
(d, br, 1H, aryl C-H, 3JHH = 8 Hz). 13C{1H} NMR (100.6 MHz, 298 K,
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CD2Cl2): δ 18.1 ppm (m, CH3 of Pr), 23.3 (d, CH of Pr, JCP = 27
Hz), 25.9 (s, CH3 of lutidine), 123.5 (d, aryl C-H, 4JCP = 2 Hz), 123.7
(d, aryl C-H, 4JCP = 1.0 Hz), 125.1 (d, aryl Cq, 1JCP = 30 Hz), 126.2 (s,
aryl C-H), 126.7 (d, aryl C-H, 3JCP = 6 Hz), 130.1 (d, aryl C-H, 4JCP
=
2
2 Hz), 130.5 (s, aryl C-H), 133.3 (d, aryl C-H, JCP = 13 Hz), 138.6,
F
dx.doi.org/10.1021/om400288u | Organometallics XXXX, XXX, XXX−XXX