Aminophenolate Ligands and Their Use in Propylene Oxide Polymerization
2d: Yield: 81%. 1H NMR (300 MHz, C6D6): δ = –0.41 (s, 6 H,
7.5 Hz, 1 H, Ph), 7.60–7.65 (m, 2 H, Ph), 7.69–7.77 (m, 4 H, Ph)
AlMe2), 1.65 (s, 9 H, tBu), 1.81 (s, 3 H, NMe), 1.95 (br. s, 6 H, N- ppm. 13C{1H} NMR (75 MHz, CD2Cl2): δ = –11.0 (AlMe), 43.4
CH2CH2-N), 2.64 (m, 2 H, N-CH2CH2-N), 3.24 (s, 2 H, PhCH2),
(NMe), 49.8 (N-CH2CH2-N), 51.6 (N-CH2CH2-N), 58.5 (PhCH2),
3
4
3
6.65 (dd, JH,H = 7.3 Hz, JH,H = 1.8 Hz, 1 H, Ph), 6.80 (t, JH,H 121.7 (Ph), 127.1 (Ph), 129.6 (Ph), 129.7 (Ph), 130.1 (Ph), 131.5
3
4
= 7.4 Hz, 1 H, Ph), 7.41 (dd, JH,H = 7.7 Hz, JH,H = 1.8 Hz, 1 H,
Ph) ppm. 13C{1H} NMR (75 MHz, C6D6): δ = –8.9 (AlMe2), 29.6
(CMe3), 34.8 (CMe3), 45.2 (NMe), 50.1 (N-CH2CH2-N), 54.6 (N-
CH2CH2-N), 59.6 (PhCH2), 116.7 (Ph), 117.6 (Ph), 120.6 (Ph),
138.2 (Ph), 138.8 (Ph), 159.2 (Ph) ppm. C18H31AlN2O (318.43):
calcd. C 67.89, H 9.81; found C 67.98, H 9.77.
(Ph), 133.3 (Ph), 135.0 (Ph), 136.9 (Ph), 147.4 (Ph) ppm.
[(2-{CH2N(C4H8O)}-6-tBuC6H3O)AlMe·(2-{CH2N(C4H8O)}-6-
tBuC6H3O)AlMe2][MeB(C6F5)3] ([3c][MeB(C6F5)3]): In a glove
box, neutral complex 2c (0.66 mmol) was added into a small
Schlenk flask and dissolved in dichloromethane (2 mL). At room
temperature and under vigorous stirring, an equimolar quantity of
B(C6F5)3 (0.66 mmol) was then added. The resulting colourless
solution was stirred for 30 min at room temperature and then evap-
orated to dryness to quantitatively yield the salt species [3c][MeB-
(C6F5)3] as a colourless oil, as deduced from 1H, 13C and 19F NMR
η2-N,O-[6-{CH2N(C4H8LЈ)}-2-CPh3-4-MeC6H3O]AlMe2 (2e, LЈ =
O; 2f, LЈ = NMe): Aminophenolate aluminium dimethyl complexes
2e and 2f were synthesized by using the same procedure as that for
2a and 2b. Pure 2e and 2f were obtained as analytically pure colour-
less crystalline solids after recrystallization of the crude mixture
1
spectroscopic data. H NMR (300 MHz, CD2Cl2): δ = –0.68 (s, 6
1
from pentane/CH2Cl2 (9:1) at –35 °C. Data for 2e: Yield: 90%. H
H, AlMe2), –0.22 (s, 3 H, AlMe), 1.35 (s, 9 H, tBu), 1.38 (br. s, 9
H, tBu), 2.72–2.81 (m, 4 H, N-CH2CH2-O), 3.11–3.41 (m, 4 H, N-
CH2CH2-O), 3.63–3.69 (m, 2 H, N-CH2CH2-O), 3.93–3.99 (m, 2
H, N-CH2CH2-O), 4.05–4.13 (m, 2 H, N-CH2CH2-O), 4.22–4.33
(m, 2 H, N-CH2CH2-O), 4.46 (s, 2 H, PhCH2), 4.52 (s, 2 H,
NMR (300 MHz, C6D6): δ = –0.85 (s, 6 H, AlMe2), 1.63–1.72 (m,
2 H, N-CH2CH2-O), 2.15 (s, 3 H, PhCH3), 2.37–2.41 (m, 2 H, N-
CH2CH2-O), 3.10–3.20 (m, 4 H, N-CH2CH2-O), 3.21 (s, 2 H,
PhCH2), 6.45 (br. s, 1 H, Ph), 6.98–7.15 (m, 15 H, CPh3), 7.39 (br.
s, 1 H, Ph) ppm. 13C{1H} NMR (75 MHz, C6D6): δ = –9.3
(AlMe2), 20.7 (Ph-CH3), 51.4 (N-CH2CH2-O), 59.5 (N-CH2CH2-
O), 61.6 (PhCH2), 63.7 (CPh3), 119.2 (Ph), 124.4 (Ph), 125.2 (Ph),
129.3 (Ph), 131.4 (Ph), 132.5 (Ph), 136.6 (Ph), 146.7 (Ph), 146.0
(Ph), 156.0 (Ph) ppm. C33H36AlNO2 (505.63): calcd. C 78.39, H
7.18, N 2.77; found C 82.06, H 7.58, N 2.63. Data for 2f: Yield:
3
3
PhCH2), 6.78 (t, JH,H = 7.6 Hz, 1 H, Ph), 6.87 (t, JH,H = 7.6 Hz,
3
4
1 H, Ph), 7.06 (dd, JH,H = 7.6 Hz, JH,H = 1.6 Hz, 1 H, Ph), 7.13
(dd, JH,H = 7.6 Hz, JH,H = 1.6 Hz, 1 H, Ph), 7.42 (dd, JH,H
3
4
3
=
4
3
4
7.9 Hz, JH,H = 1.6 Hz, 1 H, Ph), 7.51 (dd, JH,H = 7.9 Hz, JH,H
= 1.6 Hz, 1 H, Ph) ppm. 13C{1H} NMR (75 MHz, CD2Cl2): δ =
–11.7 (AlMe), –9.8 (AlMe), 28.9 (CMe3), 29.3 (CMe3), 34.7
(CMe3), 35.2 (CMe3), 51.2 (N-CH2CH2-O), 52.3 (N-CH2CH2-O),
56.3 (N-CH2CH2-O), 58.7 (N-CH2CH2-O), 61.2 (PhCH2), 62.5
(PhCH2), 118.2 (Ph), 119.1 (Ph), 120.5 (Ph), 120.9 (Ph), 128.5 (Ph),
128.7 (Ph), 129.5 (Ph), 130.2 (Ph), 139.4 (Ph), 140.2 (Ph), 154.5
(Ph), 156.2 (Ph) ppm.
1
88%. H NMR (300 MHz, C6D6): δ = –0.80 (s, 6 H, AlMe2), 1.82
(s, 3 H, NMe), 1.89–2.00 (m, 6 H, N-CH2CH2-N), 2.15 (s, 3 H,
PhCH3), 2.57–2.63 (m, 2 H, N-CH2CH2-N), 3.31 (s, 2 H, PhCH2),
6.49 (br. s, 1 H, Ph), 7.11–7.16 (m, 9 H, CPh3), 7.40 (br. s, 1 H,
Ph), 7.49–7.52 (m, 6 H, Ph) ppm. 13C{1H} NMR (75 MHz, C6D6):
δ = –9.3 (AlMe2), 20.70 (Ph-CH3), 45.20 (NMe), 49.1 (N-CH2CH2-
O), 51.0 (N-CH2CH2-O), 62.5 (PhCH2), 63.7 (CPh3), 119.6 (Ph),
124.3 (Ph), 125.1 (Ph), 127.0 (Ph), 129.0 (Ph), 129.2 (Ph), 131.8
(Ph), 136.6 (Ph), 146.7 (Ph), 156.0 (Ph) ppm. C34H39AlN2O
(518.67): calcd. C 78.73, H 7.58, N 5.40; found C 77.88, H 7.47, N
5.30.
[η2-N,O-(2-{CH2N(C4H8O)}-6-tBuC6H3O)AlMe(THF)][MeB-
(C6F5)3] ([3cЈ][MeB(C6F5)3]): In a glove box, neutral complex 2c
(0.66 mmol) was added into a small Schlenk flask and dissolved in
dichloromethane (2 mL). To this solution was added THF
(1 equiv., 53 µL, 0.66 mmol) by syringe. At room temperature and
under vigorous stirring, an equimolar quantity of B(C6F5)3
(0.66 mmol) was then added. The resulting colourless solution was
stirred for 30 min at room temperature and then evaporated to dry-
ness to yield a colourless oil (quantitative by 1H NMR). Numerous
attempts to isolate the salt species [3cЈ][MeB(C6F5)3] were unsuc-
[η3-N,O,LЈ-(2-{CH2N(C4H8LЈ)}-6-PhC6H3O)AlMe][MeB(C6F5)3]
(3a+, LЈ = O; 3b+, LЈ = NMe): In a glove box, neutral complex 2a
or 2b (0.3 mmol) was charged into a small Schlenk flask and dis-
solved in dichloromethane (2 mL). At room temperature and under
vigorous stirring, an equimolar quantity of B(C6F5)3 (0.3 mmol)
was added. The resulting colourless solution was stirred for 30 min
at room temperature and then evaporated to dryness to yield a
colourless oil. Trituration with cold pentane provoked the precipi-
tation of a white solid. The solvent was filtered off, and the white
solid residue was dried under vacuum to afford the corresponding
salt species [3a][MeB(C6F5)3] and [3b][MeB(C6F5)3] in excellent
1
cessful and its identity was determined by H and 13C NMR spec-
1
troscopy. H NMR (300 MHz, CD2Cl2): δ = –0.19 (s, 3 H, AlMe),
1.42 (br. s, 9 H, tBu), 2.30 (m, 4 H, H(β)-THF), 2.80–2.88 (m, 2
H, N-CH2CH2-O), 3.22–3.30 (m, 2 H, N-CH2CH2-O), 3.72–3.80
(m, 2 H, N-CH2CH2-O), 4.05–4.13 (m, 2 H, N-CH2CH2-O), 4.16
3
(s, 2 H, PhCH2), 4.46 [m, 4 H, H(α)-THF], 6.91 (t, JH,H = 7.6 Hz,
3
4
1 H, Ph), 7.06 (dd, JH,H = 7.6 Hz, JH,H = 1.6 Hz, 1 H, Ph), 7.42
(dd, 3JH,H = 7.9 Hz, 4JH,H = 1.6 Hz, 1 H, Ph) ppm. 13C{1H} NMR
(75 MHz, CD2Cl2): δ = –14.2 (AlMe), 25.4 [C(β)-THF], 29.3
(CMe3), 34.7 (CMe3), 51.2 (N-CH2CH2-O), 58.7 (N-CH2CH2-O),
61.2 (PhCH2), 75.9 [C(α)-THF], 118.2 (Ph), 120.5 (Ph), 128.5 (Ph),
129.5 (Ph), 139.6 (Ph), 155.0 (Ph) ppm.
1
yields. Data for 3a+: Yield: 97%. H NMR (300 MHz, CD2Cl2): δ
= –1.28 (s, 3 H, AlMe), 2.97–3.05 (m, 1 H, N-CH2CH2-O), 3.40–
3.62 (m, 3 H, N-CH2CH2-O), 3.84–4.02 (m, 2 H, N-CH2CH2-O),
4.05–4.27 (m, 4 H, PhCH2 and N-CH2CH2-O), 7.24–7.27 (m, 2 H,
Ph), 7.35–7.37 (m, 2 H, Ph), 7.40–7.45 (m, 1 H, Ph), 7.52–7.55 (m,
3 H, Ph) ppm. 13C{1H} NMR (75 MHz, CD2Cl2): δ = –13.4
(AlCH3), 49.8 (N-CH2CH2-O), 57.2 (N-CH2CH2-O), 66.9 [η3-N,O,N-(2-{CH2N(C4H8NMe)}-6-tBuC6H3O)AlMe][MeB-
(PhCH2), 120.4 (Ph), 126.6 (Ph), 129.0 (Ph), 129.7 (Ph), 130.0 (Ph), (C6F5)3] ([3d][MeB(C6F5)3]): Cationic aluminium methyl complex
131.3 (Ph), 134.4 (Ph), 134.8 (Ph), 136.4 (Ph), 146.4 (Ph) ppm. [3d][MeB(C6F5)3] was synthesized by using the same procedure as
Data for 3b+: Yield: 95%. 1H NMR (300 MHz, CD2Cl2): δ = –0.93 that used for [3a,b][MeB(C6F5)3]. Pure [3d][MeB(C6F5)3] was ob-
(s, 3 H, AlMe), 2.05 (s, 3 H, NMe), 2.52–2.62 (m, 1 H, N-CH2CH2- tained as a white solid in 90% yield but could not be obtained as an
N), 2.79–3.00 (m, 4 H, N-CH2CH2-N), 3.33–3.46 (m, 2 H, N- analytically pure compound, which is presumably due to its poor
1
CH2CH2-N), 3.62–3.73 (m, 1 H, N-CH2CH2-N), 3.93 (d, JH,H
=
stability (t1/2 ≈ 16 h in CD2Cl2 at room temperature). 1H NMR
(300 MHz, CD2Cl2): δ = –0.17 (s, 3 H, AlMe), 1.41 (s, 9 H, tBu),
2.86 (s, 3 H, NMe), 2.99–3.13 (m, 4 H, N-CH2CH2-N), 3.42–3.60
14.4 Hz, 1 H, PhCH2), 4.18 (d, 1JH,H = 14.4 Hz, 1 H, PhCH2), 7.35
3
4
3
(dd, JH,H = 7.4 Hz, JH,H = 1.7 Hz, 1 H, Ph), 7.44 (t, JH,H
=
Eur. J. Inorg. Chem. 2009, 4701–4709
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
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