Hydrolysis Rate of Fullerene Derivatives: A Comparative Study
FULL PAPER
NMR (62.5 MHz, CDCl3, 25 °C): δ = 7.41, 13.83, 18.89, 27.26,
34.63, 45.08, 62.53 ppm. GC-MS (MW = 263): m/z (%) = 79 (57),
135 (29), 176 (63), 190 (92), 232 (100), 247 (79).
Methyl N-[3-(Trimethoxysilyl)propyl]fullero[c]pyrrolidine-2-carbox-
ylate (1): Starting materials: [60]Fullerene (101 mg, 140 µmol) and
methyl N-[3-(trimethoxysilyl)propyl]aziridine-2-carboxylate (16,
85 mg, 322 µmol) in 1,2-dichlorobenzene (100 mL), heated to reflux
for 3 h. Product 1 was obtained as a brown solid. Yield 40 mg
(29%), recovered [60]fullerene: 50 mg (49%). Rf = 0.7, toluene/ethyl
General Procedure for the Synthesis of Methyl N-[3-(Trialkoxysilyl)-
propyl]aziridine-2-carboxylates
1
acetate, 9:1. H NMR (250 MHz, C6D6, 25 °C): δ = 0.88 (m, 2 H),
A solution of the appropriate 3-(trialkoxysilyl)propan-1-amine and
triethylamine in dry benzene was slowly added to a solution of
methyl 2,3-dibromopropanoate in benzene, and cooled to 5 °C. The
mixture was heated to reflux for 2 h, and after cooling to room
temperature, the precipitated salts were filtered. The solvent was
evaporated affording the desired product, which was used without
further purification.
1.98 (m, 2 H), 2.89 (m, 1 H), 3.23 (m, 1 H), 3.53 (s, 9 H), 3.61 (s,
3 H), 4.18 (d, J = 9.1 Hz, 1 H), 5.01 (d, J = 9.1 Hz, 1 H), 5.06 (s,
1 H) ppm. 13C NMR (62.9 MHz, CDCl3/CS2, 1:1, 25 °C): δ = 6.83,
21.59, 50.32, 51.73, 54.82, 64.87, 69.25, 72.43, 135.22, 135.87,
136.37, 137.55, 139.47, 139.66, 140.08, 141.60, 141.68, 141.75,
141.79, 141.92, 142.02, 142.41, 142.45, 142.88, 144.22, 144.26,
144.34, 144.44, 145.04, 145.08, 145.22, 145.27, 145.38, 145.43,
145.51, 145.56, 145.61, 145.84, 145.97, 146.02, 146.06, 146.14,
147.06, 147.15, 150.82, 153.44, 154.40, 154.55, 169.81 ppm. IR
Methyl N-[3-(Triisopropoxysilyl)propyl]aziridine-2-carboxylate (14):
Starting materials: 3-(Triisopropoxysilyl)propan-1-amine (12,
980 mg, 3.72 mmol) and triethylamine (1.2 mL, 8.61 mmol) in ben-
zene (5 mL), methyl 2,3-dibromopropanoate (910 mg, 3.69 mmol)
in benzene (3.5 mL). Product 14 was obtained as a pale yellow oil.
(KBr): ν = 1755, 1735, 1166, 1102, 1076, 575, 526 cm–1. MALDI-
˜
MS (MW = 984): m/z = 985 [M+H]+. UV/Vis (THF): λmax (ε,
mol–1 dm3 cm–1) = 254 (124100), 307 (42650), 430 (4800), 698
(520) nm. C70H21NO5Si (984): calcd. C 85.44, H 2.15, N 1.42;
found C 79.35, H 2.13, N 1.23. HPLC (toluene/ethyl acetate, 9:1):
RT = 9.58 min, purity 98%.
1
Yield 898 mg (70%). H NMR (250 MHz, C6D6, 25 °C): δ = 0.56
(m, 2 H), 1.14 (d, J = 5.9 Hz, 18 H), 1.54 (m, 1 H), 1.67 (m, 2 H),
2.02 (m, 1 H), 2.12 (m, 1 H), 2.28 (m, 2 H), 3.68 (s, 3 H), 4.15
(hept, J = 5.9 Hz, 3 H) ppm. 13C NMR (62.5 MHz, C6D6, 25 °C):
Methyl N-[3-(Tributoxysilyl)propyl]fullero[c]pyrrolidine-2-carboxyl-
ate (3): Starting materials: [60]Fullerene (260 mg, 361 µmol) and
methyl N-[3-(tributoxysilyl)propyl]aziridine-2-carboxylate (15,
300 mg, 700 µmol) in 1,2-dichlorobenzene (220 mL), heated to re-
flux for 2 h. Product 3 was obtained as a brown solid. Yield 119 mg
(30%), recovered [60]fullerene: 127 mg (49%). Rf = 0.5, toluene/
ethyl acetate, 95:5. 1H NMR (250 MHz, C6D6, 25 °C): δ = 0.82 (m,
2 H), 0.92 (t, J = 6.8 Hz, 9 H), 1.36 (m, 6 H), 1.53 (m, 6 H), 1.98
(m, 2 H), 2.92 (m, 1 H), 3.25 (m, 1 H), 3.74 (t, J = 6.8 Hz, 6 H),
3.79 (s, 3 H), 4.30 (d, J = 9.1 Hz, 1 H), 5.04 (d, J = 9.1 Hz, 1 H),
5.06 (s, 1 H) ppm. 13C NMR (62.5 MHz, CDCl3, 25 °C): δ = 7.91,
14.00, 19.17, 21.86, 34.73, 51.44, 54.59, 62.21, 64.66, 69.16, 127.12,
127.51, 127.89, 135.70, 136.01, 136.44, 137.35, 139.75, 139.94,
140.33, 140.41, 141.80, 141.87, 142.19, 142.30, 142.37, 142.75,
142.77, 142.82, 143.18, 143.32, 144.49, 144.54, 144.73, 144.88,
145.29, 145.38, 145.57, 145.69, 145.92, 146.05, 146.14, 146.20,
146.27, 146.28, 146.36, 146.41, 146.54, 146.73, 146.95, 147.29,
δ
=
9.96, 23.71, 25.77, 34.03, 37.41, 51.34, 63.86, 65.06,
170.95 ppm. GC-MS (MW = 347): m/z (%) = 45 (36), 63 (35), 79
(100), 121 (40), 202 (30), 230 (33), 260 (57). IR (neat): ν =
˜
1752 cm–1.
Methyl N-[3-(Tributoxysilyl)propyl]aziridine-2-carboxylate (15):
Starting materials: 3-(Tributoxysilyl)propan-1-amine (13, 806 mg,
3.27 mmol) and triethylamine (1.2 mL, 8.61 mmol) in benzene
(5 mL), methyl 2,3-dibromopropanoate (900 mg, 3.63 mmol) in
benzene (3.5 mL). Product 15 was obtained as a pale yellow oil.
Yield 900 mg (71%). 1H NMR (250 MHz, CDCl3, 25 °C): δ = 0.58
(m, 2 H), 0.88 (t, J = 6.8 Hz, 9 H), 1.33 (m, 6 H), 1.51 (m, 7 H),
1.69 (m, 2 H), 2.01 (m, 1 H), 2.13 (m, 1 H), 2.21 (m, 1 H), 2.35
(m, 1 H), 3.67 (s, 3 H), 3.69 (t, J = 6.8 Hz, 6 H) ppm. 13C NMR
(62.5 MHz, C6D6, 25 °C): δ = 7.79, 13.75, 18.82, 22.80, 34.46,
34.53, 37.08, 52.08, 62.40, 63.62, 171.41 ppm. GC-MS (MW = 389)
m/z (%) = 79 (42), 93 (22), 247 (18), 302 (100), 316 (43), 389 (1).
IR (neat): ν = 1751 cm–1.
˜
147.32, 153.79, 154.62, 154.70, 156.82, 169.05 ppm. IR (KBr): ν =
˜
1757, 1739, 1166, 1116, 1089, 575, 527 cm–1. MALDI-MS (MW
1110): m/z
1111 [M+H]+. UV/Vis (THF): λmax (ε,
=
Methyl N-[3-(Trimethoxysilyl)propyl]aziridine-2-carboxylate (16):
Starting materials: 3-(Trimethoxysilyl)propan-1-amine (764 mg,
4.27 mmol) and triethylamine (1.2 mL, 8.61 mmol) in benzene
(5 mL), methyl 2,3-dibromopropanoate (1.05 g, 4.27 mmol) in ben-
zene (3.5 mL). Product 16 was obtained as a pale yellow oil. Yield
=
mol–1 dm3 cm–1) = 254 (135400), 308 (44700), 430 (4480), 699
(390) nm. C79H39NO5Si (1110): calcd. C 85.46, H 3.54, N 1.26;
found C 82.40, H 3.63, N 1.10. HPLC (toluene/ethyl acetate, 95:5):
RT = 5.95 min, purity 98%.
1
843 mg (80%). H NMR (250 MHz, C6D6, 25 °C): δ = 0.67 (m, 2
H), 1.14 (d, J = 1.46 Hz, 1 H), 1.68 (m, 2 H), 1.81 (m, 1 H), 2.05
(m, 3 H), 3.36 (s, 3 H), 3.42 (s, 9 H) ppm. 13C NMR (62.5 MHz,
C6D6, 25 °C): δ = 7.06, 23.17, 33.99, 37.24, 50.21, 51.38, 63.44,
170.96 ppm. GC-MS (MW = 263): m/z (%) = 59 (29), 91 (59), 121
Methyl N-[3-(Triisopropoxysilyl)propyl]fullero[c]pyrrolidine-2-car-
boxylate (4): Starting materials: [60]Fullerene (195 mg, 270 µmol)
and methyl N-[3-(triisopropoxysilyl)propyl]aziridine-2-carboxylate
(14, 205 mg, 590 µmol) in 1,2-dichlorobenzene (150 mL), heated to
reflux for 2 h. Product 4 was obtained as a brown solid. Yield
135 mg (47%), recovered [60]fullerene: 89 mg (45%). Rf = 0.6, tolu-
ene/ethyl acetate, 95:5. 1H NMR (250 MHz, C6D6, 25 °C): δ = 0.93
(m, 2 H), 1.27 (d, J = 5.9 Hz, 18 H), 2.14 (m, 2 H), 2.94 (m, 1 H),
3.33 (m, 1 H), 3.56 (s, 3 H), 4.21 (d, J = 9.2 Hz, 1 H), 4.31 (hept,
J = 5.9 Hz, 3 H) 5.06 (d, J = 9.2 Hz, 1 H), 5.14 (s, 1 H) ppm. 13C
NMR (62.5 MHz, CD2Cl2, 25 °C): δ = 9.96, 22.45, 22.83, 25.83,
51.81, 65.10, 69.67, 72.81, 77.38, 135.59, 136.23, 136.69, 137.85,
139.82, 139.98, 140.39, 140.44, 141.94, 141.99, 142.13, 142.21,
142.26, 142.39, 142.73, 142.77, 143.20, 144.57, 144.61, 144.70,
144.76, 145.38, 145.54, 145.60, 145.75, 145.80, 145.90, 146.04,
146.07, 146.17, 146.35, 146.46, 147.38, 147.48, 151.44, 154.04,
(100), 172 (21), 176 (38), 204 (28), 263 (1). IR (film): ν = 1736 cm–1.
˜
General Procedure for the Synthesis of Methyl N-[3-(Trialkoxysilyl)-
propyl]fullero[c]pyrrolidine-2-carboxylates
A solution of [60]fullerene and the appropriate methyl N-[3-(trialk-
oxysilyl)propyl]aziridine-2-carboxylate in 1,2-dichlorobenzene was
heated to reflux for 2–5 h. After evaporation of the solvent, the
product was purified by flash chromatography (SiO2, 63–100 µm)
with toluene to remove unreacted [60]fullerene, and then with a
mixture of toluene/ethyl acetate. The compound was dissolved with
a minimum amount of toluene, precipitated by the addition of
CH3CN, washed several times with CH3CN, and dried under re-
duced pressure.
154.88, 155.14, 169.90 ppm. IR (KBr): ν = 1767, 1738, 1166, 1119,
˜
Eur. J. Org. Chem. 2006, 2934–2941
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
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