Table 1 NMR spectroscopic data for iminophosphorane compounds
Compound
NMR data
4-ButC6H4CH2P(Ph)2᎐᎐NC6H2Me3-2,4,6 1 (CDCl3, 20 ЊC)
TiCl4{4-ButC6H4CH2P(Ph)2᎐᎐NC6H2Me3-2,4,6} 2 (C6D6, 20 ЊC)
TiCl3{4-ButC6H4CHP(Ph)2᎐᎐NC6H2Me3-2,4,6} 3 (CD2Cl2, 20 ЊC)
1H NMR (300.13 MHz): δ 1.67 (s, 9H, CMe3), 2.13 (s, 6H, 2CH3), 2.33 (s,
3H, CH3), 3.55 (d, JHP = 12.96 Hz, 2H, CH2), 6.80–7.75 (m, 16H, Ph).
13C{1H} NMR (75.46 MHz): δ 20.76 (s, p-CH3), 21.85 (s, o-CH3), 31.15 (s,
CMe3), 34.10 (s, CMe3), 38.28 (d, JCP = 60.37 Hz, 1C, CH2), 124.93–149.05
(m, Ph).
31P NMR (121.49 MHz): δ Ϫ10.12.
1H NMR (300.13 MHz): δ 1.06 (s, 9H, CMe3), 1.94 (s, 3H, CH3), 2.50 (s,
6H, 2CH3), 5.02 (d, JHP = 17.32 Hz, 2H, CH2), 6.39–7.41 (m, 16H, Ph).
13C{1H} NMR (C7D8, 20 ЊC, 75.46 MHz): δ 20.78 (s, p-CH3), 22.30 (s, o-
CH3), 31.15 (s, CMe3), 34.30 (s, CMe3), 39.34 (br, CH3), 124.52–150.29
(Ph).
31P NMR (121.49 MHz): δ 48.44.
1H NMR (300.13 MHz): δ 1.14 (s, 9H, CMe3), 1.96 (s, 3H, CH3), 2.11 (s,
3H, CH3), 2.47 (s, 3H, CH3), 4.37 (d, JHP = 11.4 Hz, H, CH), 6.48–8.13 (m,
16H, Ph).
13C{1H} NMR (75.46 MHz): δ 20.91 (s, CH3), 21.74 (s, CH3), 22.90 (s,
CH3), 31.33 (s, CMe3), 34.39 (s, CMe3), 125.68–149.42 (Ph).
31P NMR (121.49 MHz): δ 30.29.a
Li[4-ButC6H4CHP(Ph)2᎐᎐NC6H2Me3-2,4,6] 4 (C6D6, 20 ЊC)
[4-ButC6H4CH2P(Ph)2NHC6H2Me3-2,4,6]ϩClϪ 5 (C6D6, 20 ЊC)
1H NMR (300.13 MHz): δ 1.24 (s, 9H, CMe3), 1.85 (s, 6H, 2CH3), 2.22 (s,
3H, CH3), 3.04 (d, JHP = 13.87 Hz, 1H, CH), 6.79–7.79 (m, 16H, Ph).
13C{1H} NMR (75.46 MHz): δ 20.59 (s, CH3), 21.42 (s, CH3), 31.17 (s,
CMe3), 33.65 (s, CMe3), 36.96 (d, JCP = 138.1 Hz, CH), 119.81–138.36 (Ph).
31P NMR (CDCl3, 20 ЊC, 121.49 MHz): δ 11.66.
1H NMR (300.13 MHz): δ 1.09 (s, 9H, CMe3), 1.93 (s, 3H, p-CH3), 2.32 (s,
6H, o-CH3), 5.63 (d, JHP = 17.72 Hz, 2H, CH2), 6.47–8.12 (m, 16H, Ph).
13C{1H} NMR (75.46 MHz): δ 20.87 (s, p-CH3), 21.16 (s, o-CH3), 31.46 (s,
CMe3), 34.45 (s, CMe3), 122.06–150.18 (Ph).a
31P NMR (121.49 MHz): δ 41.45 ppm.
ZrCl4{4-ButC6H4CH2P(Ph)2᎐᎐NC6H2Me3-2,4,6} 6 (CD2Cl2, 20 ЊC)
ZrCl3{4-ButC6H4CHP(Ph)2᎐᎐NC6H2Me3-2,4,6} 7 (CDCl3, 20 ЊC)
1H NMR (300.13 MHz): δ 1.18 (s, 9H, CMe3), 2.13 (s, 3H, CH3), 2.13 (s,
6H, 2CH3), 5.02 (br, 2H, CH2), 6.56–7.60 (m, 16H, Ph).
31P NMR (121.49 MHz): δ 46.47.
1H NMR (300.13 MHz): δ 1.20 (s, 9H, CMe3), 2.11 (s, 3H, CH3), 2.12 (s,
3H, CH3), 2.42 (s, 3H, CH3), 3.92 (br, H, CH), 6.71–7.41 (m, 16H, Ph).
13C{1H} NMR (75.46 MHz): δ 21.33 (s, CH3), 21.93 (s, CH3), 22.95 (s,
CH3), 31.64 (s, CMe3), 34.77 (s, CMe3), 125.84–135.43 (Ph).a
31P NMR (121.49 MHz): δ 21.28.
Zr(NMe2)3{4-ButC6H4CHP(Ph)2᎐᎐NC6H2Me3-2,4,6} 8 (C6D6,
20 ЊC)
1H NMR (300.13 MHz): δ 1.19 (s, 9H, CMe3), 2.13 (br, 9H, CH3), 3.07 (s,
18H, NMe2), 3.15 (d, JHP = 7.11 Hz, 1H, CH), 6.75–7.64 (m, 16H, Ph).
13C{1H} NMR (75.46 MHz): δ 20.59 (s, p-CH3), 21.01 (br, o-CH3), 31.34 (s,
CMe3), 33.80 (s, CMe3), 39.34 (d, JCP = 83.75 Hz, CH), 42.80 (s, NMe2),
124.45–143.55 (Ph).
31P NMR (121.49 MHz): δ 24.68.
ZrCl4{4-ButC6H4CH(SiMe3)P(Ph)2᎐᎐NC6H2Me3-2,4,6} 9 (CD2Cl2,
20 ЊC)
1H NMR (300.13 MHz): δ 0.19 (s, 9H, SiMe3), 1.17 (s, 9H, CMe3), 2.24 (s,
6H, o-CH3), 2.28 (s, 3H, p-CH3), 4.04 (d, JHP = 15.63 Hz, 1H, CH), 6.4–
7.83 (m, 16H, Ph).
13C{1H} NMR (75.46 MHz): δ 5.01 (s, SiMe3), 22.77 (s, p-CH3), 23.54 (s, o-
CH3), 33.28 (s, CMe3), 35.74 (d, JCP = 60.74 Hz, CH), 36.64 (s, CMe3),
121.98–154.03 (Ph).
31P NMR (121.49 MHz): δ 45.47.
4-ButC6H4CH(SiMe3)P(Ph)2᎐᎐NC6H2Me3-2,4,6 10 (C6D6, 20 ЊC)
1H NMR (300.13 MHz): δ 0.09 (s, 9H, SiMe3), 1.19 (s, 9H, CMe3), 2.31 (s,
3H, CH3), 2.38 (s, 6H, 2CH3), 3.3 (d, JHP = 13.90 Hz, 1H, CH), 6.80–7.90
(m, 16H, Ph).
13C{1H} NMR (75.46 MHz): δ 0.24 (s, SiMe3), 20.61 (s, p-CH3), 22.46 (s, o-
CH3), 31.22 (s, CMe3), 34.10 (s, CMe3), 42.24 (d, JCP = 80.78 Hz, CH),
124.90–148.52 (Ph).
31P NMR (121.49 MHz): δ Ϫ5.21.
a The P–CH 13C NMR signal could not be located.
The latter is typical of an aminophosphonium cation, [4-
ButC6H4CH2P(Ph)2–NHC6H2Me3-2,4,6]ϩ, formed by proton-
ation of the ligand. This implies that during the reaction HCl
must have been produced. Since care was taken to exclude trace
hydrolysis, a source of protons is C–H activation of 2 to give
synthesis of this compound from Li[4-ButC H CHP(Ph) ᎐
᎐
6
4
2
NC6H2Me3-2,4,6] 4 and TiCl4. The product was isolated as a
yellow microcrystalline solid which showed the expected 31P
NMR signal at δ 30.3. The identity of the second by-product
was confirmed by passing HCl through a solution of 1, which
resulted in the precipitation of [4-ButC6H4CH2P(Ph)2NHC6-
H2Me3-2,4,6]Cl 5. The compound exhibits a 31P NMR signal at
δ 41.5. Efforts to prepare alkyl derivatives of 3 by alkylation
with MeMgCl or PhCH2MgCl were unsuccessful. Monitoring
these reactions by means of 31P NMR spectroscopy showed
that complex product mixtures were formed.
HCl and TiCl {4-ButC H CHP(Ph) ᎐NC H Me -2,4,6} 3. A
᎐
3
6
4
2
6
2
3
phosphorus chemical shift of ca. δ 30 would be in agreement
with that formulation. Interestingly, the addition of triethyl-
amine or proton sponge to a solution of 2 before the reaction
mixture is allowed to warm to room temperature prevented the
formation of 3 or of phosphonium cations and instead led to
simple displacement of the iminophosphine ligand to give
TiCl4(NEt3)2.
The reaction of 1 with ZrCl4 in toluene affords ZrCl4{4-
ButC H CH P(Ph) ᎐NC H Me -2,4,6} 6 in high yield (Scheme
᎐
6
4
2
2
6
2
3
The formation of 3 was confirmed by the independent
2), characterised by a 31P NMR signal at δ 46.5. In contrast to 2,
J. Chem. Soc., Dalton Trans., 2001, 2844–2849
2845