Alkyl Tantalum Imido Complexes
Organometallics, Vol. 25, No. 14, 2006 3405
solvents. Anal. Calcd: C, 48.39; H, 2.45; N, 1.18. Found: C, 48.05;
H, 2.60; N, 1.16.
Preparation of Phenylacetylene Insertion Product 13. In the
glovebox, a vial was charged with 79.1 mg (0.151 mmol, 1 equiv)
of 1 and 10 mL of fluorobenzene. The resulting solution was mixed
with 139 mg (0.151 mmol, 1 equiv) of [Ph3C][B(C6F5)4] and 15.4
mg (0.151 mmol, 1 equiv) of phenylacetylene. The reaction mixture
was shaken briefly before the solvent was removed under vacuum
to give a red-brown oil. The oil was washed with 3 × 10 mL of a
50:50 mixture of benzene/hexane to remove the 1,1,1,2-tetraphen-
ylethane side product. The oil was then mixed with 10 mL of
pentane, and all remaining volatile materials were removed under
vacuum to give the dark red foam 13 (88.5 mg, 48.4%). The yield
of this reaction is low due to the slight solubility of the product in
benzene. 1H NMR (C6D5Cl, 400 MHz): δ 7.54 (t, J ) 7.6 Hz, 1H,
ArH), 7.19 (m, 5H, ArH), 7.07 (m, 3H, ArH), 6.90 (m, 4H, ArH),
6.29 (bs, 2H, η2-ArH), 5.39 (s, 1H, vinyl-CH), 3.65 (d, J ) 15.6
Hz, 1H, alkenyl-CH2Ph), 3.41 (d, J ) 15.6 Hz, 1H, alkenyl-CH2-
Ph), 2.66 (d, J ) 7.6 Hz, TaCH2Ph), 2.06 (d, J ) 7.6 Hz, TaCH2-
Ph), 0.92 (CMe3). 13C{1H} NMR (C6D5Cl, 100 MHz): δ 177.1
(vinyl-CH), 169.1 (alkenyl-CPh), 153.5 (q-Ar), 148.7 (d, J ) 238
Hz, ArF), 140.9 (q-Ar), 138.6 (d, J ) 244 Hz, ArF), 137.1 (d, J )
256 Hz, ArF), 134.2 (η2-q-Ar), 131.3 (Ar), 130.8 (Ar), 128.6 (Ar),
128.6 (Ar), 124.7 (Ar), 121.6 (Ar), 119.5 (Ar), 118.5 (Ar), 114.5
(q-Ar), other aryl carbon resonances overlap with solvent reso-
nances, 68.7 (CMe3), 45.1 (TaCH2Ph), 42.9 (alkenyl-CH2Ph), 31.3
(CMe3). 11B NMR (C6D5Cl, 164.7 MHz): δ -16.7. 19F NMR
(C6D5Cl, 376.5 MHz): δ -131.7, 161.8, 165.8. Anal. Calcd: C,
49.41; H, 2.40; N, 1.15. Found: C, 49.13; H, 2.68; N, 1.21.
[Bn2(THF)2TadNCMe3][B(C6F5)4] (10). In the glovebox, a vial
was charged with 69.9 mg (0.133 mmol, 1 equiv) of 1 and 10 mL
of fluorobenzene. The resulting solution was mixed with 123 mg
(0.133 mmol, 1 equiv) of [Ph3C][B(C6F5)4] and 21.6 µL (0.266
mmol, 2 equiv) of THF. The reaction mixture was shaken briefly
before the solvent was removed under vacuum to give a red-brown
oil. The oil was washed with 3 × 10 mL of a 50:50 mixture of
benzene/hexane to remove the 1,1,1,2-tetraphenylethane side
product. The oil was then mixed with 10 mL of pentane. All volatile
materials were then removed under vacuum to give the red-orange
foam 10 (88.0 mg, 52.6%). The yield of this reaction is low due to
1
a small amount of solubility of the product in benzene. H NMR
(C6D5Cl, 500 MHz, 25 °C): δ 7.07 (t, J ) 7.5 Hz, 4H, m-ArH),
6.98 (t, J ) 7.5 Hz, 2H, p-ArH), 6.75 (d, J ) 7.5 Hz, 4H, o-ArH),
3.42 (bs, 8H, THF), 2.34 (bs, 4H, TaCH2Ph), 1.53 (bs, 8H, THF),
1.19 (s, 9H, CMe3). 1H NMR (C6D5Cl, 500 MHz, -31 °C): δ 7.07
(t, J ) 7.5 Hz, 4H, m-ArH), 6.98 (t, J ) 7.5 Hz, 2H, p-ArH), 6.75
(d, J ) 7.5 Hz, 4H, o-ArH), 3.26 (bs, 8H, THF), 2.60 (bs, 2H,
TaCH2Ph), 1.84 (bs, 2H, TaCH2Ph), 1.39 (bs, 8H, THF), 1.19 (s,
9H, CMe3). 13C{1H} NMR (C6D5Cl, 125 MHz): δ 148.7 (d, J )
236 Hz, ArF), 137.6 (t, J ) 236 Hz, ArF), all other aryl carbon
resonances overlap with the solvent resonances, 131.3 (Ar), 129.2
(Ar), 127.0 (Ar), 75.1 (bs, Ta-CH2Ph), 73.7 (THF), 69.6 (CMe3),
32.2 (CMe3), 25.3 (THF). 11B NMR (C6D5Cl, 164.7 MHz): δ
-16.6. 19F NMR (C6D5Cl, 376.5 MHz): δ -131.2, -162.1,
-166.1. Anal. Calcd: C, 47.15; H, 3.09; N, 1.10. Found: C, 46.76;
H, 3.11; N, 1.21.
Preparation of Norbornene Insertion Product 14. In the
glovebox, a vial was charged with 87.4 mg (0.166 mmol, 1 equiv)
of 1 and 10 mL of fluorobenzene. The resulting solution was mixed
with 153 mg (0.166 mmol, 1 equiv) of [Ph3C][B(C6F5)4] and 13.9
mg (0.166 mmol, 1 equiv) of norbornene. The solvent was then
removed under vacuum to give a red-brown oil. The oil was washed
with 3 × 10 mL of a 50:50 mixture of benzene/hexane to remove
the 1,1,1,2-tetraphenylethane side product. The oil was then mixed
with 10 mL of pentane, and all remaining volatile materials were
then removed under vacuum to give the light orange foam 14 (96.9
mg, 48.2%). The yield of this reaction is low due to the slight
solubility of the product in benzene. 1H NMR (C6D5Cl, 400
MHz): δ 7.25 (t, J ) 8.4 Hz, 1H, ArH), 6.95 (m, 4H, ArH), 6.77
(d, J ) 8.0 Hz, 1H, ArH), 6.58 (t, J ) 7.2 Hz, 1H, ArH), 6.51 (t,
J ) 8.4 Hz, 1H ArH), 6.25 (d, J ) 7.2 Hz, 2H, ArH), 2.61 (dd,
J ) 9.2 Hz, 5.2 Hz, 1H, CHCH2Ph), 2.32 (m, 3H, TaCH2Ph,
CHCH2Ph), 2.21 (bs, 1H, bridgehead-H), 1.88 (dd, J ) 9.2 Hz,
5.2 Hz, 1H, CHCH2Ph), 1.54 (m, 1H, CH2), 1.35 (bd, 10 Hz,
methylene bridge-CH2), 1.20 (m, 1H, CH2), 1.01 (s, 9H, CMe3),
0.85 (bd, 10 Hz, methylene bridge-CH2), 0.74 (m, 1H, CH2), 0.24
(m, 1H, CH2), -1.84 (d, 8.8 Hz, 1H, Ta-CH). 13C NMR (C6D5Cl,
125 MHz): δ 151.0 (q-Ar), 148.4 (d, J ) 236 Hz, ArF), 146.5
(q-Ar), 137.4 (t, J ) 238 Hz, ArF), 133.5 (Ar), 132.4 (Ar), 132.1
(Ar), 129.3 (Ar), 128.3 (Ar), 127.3 (Ar), 124.4 (Ar), 122.5 (Ar),
113.7 (Ar), all other carbon aryl resonances overlap with solvent
resonances, 69.9 (TaCH), 69.4 (CMe3), 60.8 (CHCH2Ph), 53.6 (CH
bridgehead), 44.2 (CH bridgehead), 44.0 (TaCH2Ph), 43.1 (CHCH2-
Ph), 39.7 (CH2), 35.7 (CH2), 31.2 (CMe3), 27.2 (CH2). 11B NMR
(C6D5Cl, 164.5): δ -16.57. 19F NMR (C6D5Cl, 376.5 MHz): δ
-131.7, 161.8, 165.8. Anal. Calcd: C, 48.74; H, 2.75; N, 1.16.
Found: C, 48.70; H, 2.93; N, 1.20.
Preparation of Diphenylacetylene Insertion Product 11. In
the glovebox, a vial was charged with 92.4 mg (0.176 mmol, 1
equiv) of 1 and 10 mL of fluorobenzene. The resulting solution
was mixed with 162.2 mg (0.176 mmol, 1 equiv) of [Ph3C]-
[B(C6F5)4] and 31.3 mg (0.166 mmol, 1 equiv) of diphenylacetylene.
The reaction was shaken briefly, and then the solvent was removed
under vacuum to give a red-brown oil. The oil was washed with
3 × 10 mL of a 50:50 mixture of benzene/hexane to remove the
1,1,1,2-tetraphenylethane side product. The oil was then mixed with
10 mL of pentane, and all remaining volatile materials were
removed under vacuum to give the red-orange foam 11 (125.7 mg,
55.4%). The yield of this reaction is low due to the slight solubility
1
of the product in benzene. H NMR (C6D5Cl, 500 MHz): δ 7.31
(m, 2H, ArH), 7.16 (m, 2H, ArH), 7.09 (t, J ) 7.0 Hz, 4H, ArH),
6.91 (m, 5H, ArH), 6.79 (t, J ) 7.5 Hz, 1H, ArH), 6.74 (t, J ) 7.5
Hz, 1H, ArH), 6.64 (m, 4H, ArH), 6.13 (t, J ) 6.0 Hz, 1H, η2-Ar),
3.72 (d, J ) 17 Hz, 1H, alkenyl-CH2Ph), 3.59 (d, J ) 17 Hz, 1H,
alkenyl-CH2Ph), 2.95 (d, J ) 12 Hz, 1H, TaCH2Ph), 2.27 (d, J )
12 Hz, 1H, TaCH2Ph), 0.98 (s, 9H, CMe3). 13C{1H} NMR (C6D5-
Cl, 500 MHz): δ 208.2 (alkenyl-CPh), 173.2 (alkenyl-CPh), 152.1
(q-Ar), 148.7 (d, J ) 236 Hz, ArF), 143.9 (q-Ar), 140.2 (q-Ar),
138.5 (d, J ) 244 Hz, ArF), 136.6 (d, J ) 238 Hz, ArF), all other
carbon aryl resonances overlap with solvent resonances, 134.8 (η2-
q-Ar), 134.4 (Ar), 131.5 (Ar), 129.8 (Ar), 129.7 (Ar), 128.9 (Ar),
128.2 (Ar), 128.0 (Ar), 127.8 (Ar), 126.5 (Ar), 126.3 (Ar), 121.6
(Ar), 120.5 (Ar), 73.2 (TaCH2Ph), 69.3 (CMe3), 46.0 (alkenyl-CH2-
Ph), 31.9 (CMe3). 11B NMR (C6D5Cl, 164.5 MHz): δ -16.56. 19
F
NMR (C6D5Cl, 376.5 MHz): δ -131.6, -161.6, -165.6. Anal.
Calcd: C, 52.08; H, 2.58; N, 1.08. Found: C, 51.93; H, 2.78; N,
1.25.
A solution of ∼25 mg of compound 14 in 1.5 mL of diethyl
ether was transferred to a vial and taken out of the glovebox. The
solution was mixed with 1 mL of 1 M HCl(aq). The mixture was
shaken and allowed to settle. The ether layer was then decanted
via pipet and filtered through 1 mL of silica in a pipet filter plug.
The filtrate was then analyzed by GC-MS. Retention time: 24.9
min. M+ ) 243 m/z.
A solution of ∼25 mg of compound 11 in 1.5 mL of diethyl
ether was transferred to a vial and taken out of the glovebox. The
solution was mixed with 1 mL of 1 M HCl(aq). The mixture was
shaken and allowed to settle. The ether layer was then decanted
via pipet and filtered through 1 mL of silica in a pipet filter plug.
The filtrate was then analyzed by GC-MS. Retention time: 22.2
min. M+ ) 270 m/z.
Preparation of cis-Cyclooctene Insertion Product 16. In the
glovebox, a vial was charged with 79.6 mg (0.151 mmol, 1 equiv)