Tungsten Alkylidene Complexes
Organometallics, Vol. 26, No. 5, 2007 1289
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(NArCl), 124.2 (quart, JFC ) 287.5 Hz, CF3), 82.4 (sept, JFC
)
powder (553 mg, 95%): 1H NMR (C6D6) δ 7.31 (s, 2 × 1 H,
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30.5 Hz, OCCH3), 46.0 (CMe3), 33.6 (CMe3), 19.3 (OCCH3); one
carbon resonance of the NArCl ligand was obscured by C6D6; 19F
NMR (C6D6) δ -76.8 (br m), -76.9 (br m). Anal. Calcd for C19H19-
Cl2F12NO2W: C, 29.40; H, 2.47; N, 1.80. Found: C, 29.21; H,
2.43; N, 1.79.
Biphen), 6.82 (d, JHH ) 8.1 Hz, 2 × 1 H, NArCl-3 and NArCl-5),
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6.09 (t, JHH ) 8.1 Hz, 1 H, NArCl-4), 4.71, 4.42, 4.35, 3.41 (m,
1JCH ) 148.9 Hz, 161.3 Hz, 153.8 Hz, 151.4 Hz, 4 × 1 H, R-CH2),
2.16, 1.79 (s, 4 × 3 H, Biphen-CH3), 1.57 (s, 2 × 9 H, Biphen-
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CMe3), -0.03, -0.27 (m, JCH ) 151.4 Hz, 153.8 Hz, 2 × 1 H,
â-CH2); 13C{1H} NMR (toluene-d8) δ 149.0, 134.2, 129.2, 128.1,
W(NArCl)(CH2CH2CH2)[OC(CF3)2Me]2. A stirred solution of
W(NArCl)(CHCMe3)(ORF6)2 (250 mg, 322 µmol) in benzene (5 mL)
was exposed to 1 atm of ethylene for 2 min. The resulting pale
yellow solution was stirred for 30 min at 25 °C. The reaction
mixture was frozen, and the volatiles were removed by lyophiliza-
tion to give a pale brown powder (213 mg, 90%): 1H NMR (C6D6)
δ 6.70 (d, 3JHH ) 8.1 Hz, 2 H, NArCl-3 and NArCl-5), 6.01 (t, 3JHH
125.9, 96.6 (1JCH ) 148.9 Hz, 153.8 Hz, R-CH2), 86.5 (1JCH
)
151.4 Hz, 161.3 Hz, R-CH2), 31.4, 20.7, 17.1, -0.1 (1JCH ) 151.4
Hz, 153.8 Hz, â-CH2). The resonances of the quarternary carbons
of the Biphen ligand could not be assigned unambiguously. The
coupling constants 1JCH were determined in an HMQC experiment.
Anal. Calcd for C33H41Cl2NO2W: C, 53.68; H, 5.60; N, 1.90.
Found: C, 53.52; H, 5.54; N, 1.82.
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) 8.1 Hz, 1 H, NArCl-4), 4.91, 4.77 (m, JCH ) 165.2 Hz, 160.6
Hz, 2 × 2 H, R-CH2), 1.59, 1.55 (br s, 2 × 3 H, OCCH3), -0.87,
-1.46 (m, 1JCH ) 166.2 Hz, 162.0 Hz, 2 × 1 H, â-CH2); 13C{1H}
NMR (C6D6) δ 147.1, 134.2, 128.9, 127.3 (NArCl), 124.7 (quart,
W(NArCl)(13CH213CH213CH2)(Biphen) was observed when
13CH2d13CH2 was employed: 13C{1H} NMR (C6D6) δ 97.7 (br d,
R-CH2), 87.5 (br d, R-CH2), -0.5 (br t, â-CH2).
1JFC ) 287.9 Hz, CF3), 103.4 (1JCH ) 160.6 Hz, 165.2 Hz, 1JWC
)
W(NArCl)(C2H4)(Biphen)(THF). Complex W(NArCl)(C3H6)-
(Biphen) (1.00 g, 1.35 mmol) was suspended in THF (4 mL), and
the mixture was stirred at 25 °C. The yellow suspended powder
dissolved to yield an orange-red solution within 2 min. After the
reaction mixture was stirred for 16 h, the product precipitated as
yellow microcrystals, which were isolated by filtration and washed
with pentane (5 mL); yield 700 mg (65%): 1H NMR (CD2Cl2) δ
7.15-7.05 (br, 1 H, Biphen and, 2 × 1 H, NArCl-3 and NArCl-5),
64.7 Hz, R-CH2), 84.5, 81.7 (OCCH3), 17.8, 17.6 (OCCH3), -4.7
(1JCH ) 162.0 Hz, 166.2 Hz, â-CH2); 1JCH values were determined
in an HMQC experiment; 19F NMR (C6D6) δ -77.4 (s), -77.5
(s). Anal. Calcd for C17H15Cl2F12NO2W: C, 27.30; H, 2.02; N, N,
1.87. Found: C, 27.08; H, 1.89; N, 1.81.
{W(µ-NArCl)[OC(CF3)2Me]2}2. Amylene (40 µL, 376 µmol)
was added to a stirred solution of W(NArCl)(CHCMe3)(ORF6)2 (250
mg, 322 µmol) in benzene (5 mL). After 15 min the bright yellow
solution turned orange, and purple microcrystals started to be
deposited. After the reaction mixture was stirred for 7 days at
25 °C, the purple product was filtered off and washed with pentane
(3 × 2 mL); yield 170 mg (75%): 1H NMR (THF-d8) δ 7.96 (d,
3JHH ) 8.1 Hz, 2 × 2 H, NArCl-3 and NArCl-5), 7.18 (t, 3JHH ) 8.1
Hz, 2 × 1 H, NArCl-4), 0.88 (s, 4 × 3 H, OCCH3); the 13C NMR
spectrum could not be obtained due to the limited stability and
solubility of [W(µ-NArCl)(ORF6)2]2 in common NMR solvents; 19
NMR (THF-d8) -79.0 (s). Anal. Calcd for C28H18-
Cl4F24N2O4W2: C, 23.82; H, 1.28; N, 1.98. Found: C, 24.03; H,
1.22; N, 2.01.
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δ 7.00 (s, 1 H, Biphen), 6.72 (t, JHH ) 8.1 Hz, 1 H, NArCl-4),
3.99 (br, 2 × 2 H, R-CH2, THF), 3.34, 3.13 (m, 2 × 1 H, WC2H4),
2.27, 2.15, 1.86 (s, 3 × 3 H, Biphen-CH3), 1.83 (br, 2 × 2 H,
â-CH2, THF), 1.42 (s, 3 H, Biphen-CH3), 1.28, 1.17 (s, 2 × 9 H,
Biphen-CMe3). Two protons in the ethylene group were obscured
by other resonances.
W(NArCl)(C2H4)(Biphen)(THF-d8). An orange solution of
W(NArCl)(C3H6)(Biphen) (150 mg, 203 µmol) in THF-d8 was kept
for 90 min at 25 °C before the NMR spectra were recorded. After
48 h the solvent was decanted to leave behind yellow crystals of
W(NArCl)(C2H4)(Biphen)(THF-d8) (90 mg, 55%): 1H NMR (THF-
d8) δ 7.08 (s, 1 H, Biphen and d, 3JHH ) 8.1 Hz, 2 × 1 H, NArCl-3
and NArCl-5), δ 6.94 (s, 1 H, Biphen), 6.72 (t, 3JHH ) 8.1 Hz, 1 H,
F
δ
W(NArCl)(CHCMe3)(Biphen)(THP). A solution of Biphen(Li2)-
(Et2O) (1.14 g mg, 2.58 mmol) in toluene (20 mL) was added
dropwise to a stirred solution of W(NArCl)(CHCMe3)(ORF6)2 (2.00
g, 2.58 mmol) in toluene (50 mL) at -30 °C. The orange solution
was stirred at 25 °C for 12 h and then stored at -30 °C for 3 h.
The colorless deposit was filtered off and washed with chilled
toluene (10 mL, -30 °C) to give an orange solution, to which THP
(4 mL) was added. After all volatiles were removed under reduced
pressure, the yellow-brownish residue was suspended in pentane
(40 mL) to precipitate W(NArCl)(CHCMe3)(Biphen)(THP) as a pale
yellow powder, which was washed with pentane (10 mL) and dried
under reduced pressure (1.80 g, 82%): 1H NMR (C6D6) δ 9.19 (s,
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NArCl-4), 3.31, 3.01 (m, JCH ) 154.4 Hz, 157.9 Hz, 2 × 1 H,
WC2H4), 2.27, 2.21, (s, 2 × 3 H, Biphen-CH3), 2.13, 2.06 (m,1JCH
) 151.7 Hz, 152.6 Hz, 2 × 1 H, WC2H4), 1.87, 1.43 (s, 2 × 3 H,
Biphen-CH3), 1.29, 1.17 (s, 2 × 9 H, Biphen-CMe3); 13C{1H} NMR
(THF-d8) δ 160.5 (aryl), 155.7 (aryl), 151.3 (aryl), 140.3 (aryl),
135.8 (aryl), 134.4 (aryl), 134.2 (aryl), 132.1 (aryl), 131.5 (aryl),
131.4 (aryl), 130.6 (aryl), 128.7 (aryl), 128.4 (aryl), 127.2 (aryl),
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127.0 (aryl), 123.9 (aryl), 55.8 (1JCH ) 152.6 Hz, 151.7 Hz, JWC
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) 37.9 Hz, WC2H4), 52.6 (1JCH ) 157.9 Hz, 154.4 Hz, JWC
)
34.5 Hz, WC2H4), 36.0, 34.7, 31.3, 30.7, 20.5, 20.2, 17.0, 16.9.
The coupling constants JCH were determined in an HMQC
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2JWH ) 8.3 Hz, JCH ) 109.4 Hz, 1 H, WCH), 7.28, 7.12 (s, 2 ×
experiment. Anal. Calcd for C36H39D8Cl2NO3W: C, 53.74; H, 6.89;
N, 1.74. Found: C, 53.68; H, 6.95; N, 1.68.
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1 H, Biphen), 7.03, 6.87 (d, 3JHH ) 8.1 Hz, 2 × 1 H, NArCl-3 and
NArCl-5), 6.15 (t, 3JHH ) 8.1 Hz, 1 H, NArCl-4), 3.24 (br, 2 × 2 H,
R-CH2, THP), 2.33, 2.03, 1.90, 1.76 (s, 4 × 3 H, Biphen-CH3),
1.72, 1.55, 1.49 (s, 3 × 9 H, CMe3), 1.04 (s, 3 × 2 H, â- and
γ-CH2, THP); 13C{1H} NMR (C6D6) δ 266.5 (WCH), 160.5 (aryl),
158.1 (aryl), 151.2 (aryl), 136.7 (aryl), 136.5 (aryl), 136.0 (aryl),
135.4 (aryl), 132.0 (aryl), 131.6 (aryl), 130.1 (aryl), 129.2 (aryl),
128.3 (aryl), 126.9 (aryl), 126.8 (aryl), 123.9 (aryl), 69.8, 46.4, 36.2,
35.3, 34.2, 33.1, 32.8, 26.1, 22.8, 20.9, 20.6, 20.0, 17.6, 17.3. Fifteen
out of 18 carbon resonances were observed. Anal. Calcd for C40H55-
Cl2NO3W: C, 56.35; H, 6.50; N, 1.64. Found: C, 56.22; H, 6.37;
N, 1.57.
W(NArCl)(C4H8)(Biphen). W(NArCl)(Biphen)(C2H4)(THF) (600
mg, 813 µmol) was suspended in benzene (50 mL), and the
degassed reaction mixture was stirred under ethylene (1 atm) at
25 °C for 15 min. Upon addition of ethylene, the yellow suspension
immediately dissolved to yield an orange-red solution. The reaction
mixture was frozen, and the volatiles were removed by lyophiliza-
tion to give an approximate 6:1 mixture of W(NArCl)(C4H8)(Biphen)
and unreacted W(NArCl)(Biphen)(C2H4)(THF). This material was
redissolved in benzene (50 mL), and the above procedure was
repeated (addition of ethylene, lyophilization) to yield W(NArCl)-
(C4H8)(Biphen) as an orange powder (500 mg, 82%): 1H NMR
(C6D6) δ 7.32, 7.13 (s, 2 × 1 H, Biphen), 6.78 (d, 3JHH ) 8.1 Hz,
W(NArCl)(C3H6)(Biphen). A yellow solution of W(NArCl)-
(CHCMe3)(Biphen)(THP) (672 mg, 788 µmol) in benzene (20 mL)
was stirred under ethylene (1 atm) at 25 °C for 16 h. The reaction
mixture was frozen, and the volatiles were removed by lyophiliza-
tion. The analytically pure product was obtained as a pale yellow
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2 × 1 H, N NArCl-3, N NArCl-5), 6.09 (t, JHH ) 8.1 Hz, 1 H, N
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NArCl-4), 3.75 (m, JCH ) 124.4 Hz, 1 H, R-CH2, WC4H8), 3.46
(m,1JCH ) 123.3 Hz, 1 H, R-CH2, WC4H8), 3.41 (m, 1JCH ) 136.7
Hz, 1 H, â-CH2, WC4H8), 3.37 (m, 1JCH ) 128.5 Hz, 1 H, R-CH2,