Synthesis of functionalized fullerenes by photoaddition of N-α-trimethylsilyl-ncarboxymethyl-N-benzylamines to C60

Article abstract of DOI:10.3987/COM-15-S(T)19

Photoaddition reactions of fullerene C₆₀ with N-α-trimethylsilyl-N-carboxymethyl-N-benzylamines, which contain various para-substituents, were explored in order to evaluate factors governing efficiencies of this potentially useful method for preparing functionalized fullerene derivatives. Observations made in this study show that two reaction pathways are followed in these photoreactions. The first involves initial formation of α-trimethylsilyl-aminium radicals and the C₆₀ anion radical by SET from the amines to the triplet excited state of C₆₀. This step is followed by desilylation to produce α-amino radicals. Coupling of these radicals with the anion radical of C₆₀ followed by protonation or with the hydrofullerene radical generated by protonation of the anion radical of C₆₀ then produces aminomethyl-1,2-dihydrofullerenes. When limited amounts of ³O₂ are present in the reaction medium, fulleropyrrolidines are generated in low yields by a competitive pathway involving formation of singlet oxygen, which undergoes sequential H-atom abstractions from the N-α-trimethylsilyl-N-carboxymethyl-N-benzylamines to produce azomethine ylide intermediates. Dipolar cyloaddition of the ylides to C₆₀ then produces fulleropyrrolidines. Photoreactions of the C₆₀ and the amines in the presence of high ³O₂ concentrations exclusively produce fulleropyrrolidine. In addition, the results show that photoreactions of non-silicon substituted, N-methyl-N-carboxymethyl-N-benzylamines with C₆₀ form fulleropyrrolidines independent of the concentration of ³O₂ present in the media.

Full text of DOI:10.3987/COM-15-S(T)19

HETEROCYCLES, Vol. 93, No. 1, 2015, pp. -. © 2016 The Japan Institute of Heterocyclic Chemistry
Received, 24th August, 2015, Accepted, 17th September, 2015, Published online, 7th October, 2015
DOI: 10.3987/COM-15-S(T)19
SYNTHESIS
OF
FUNCTIONALIZED
FULLERENES
BY
PHOTOADDITION OF N--TRIMETHYLSILYL-N-
CARBOXYMETHYL-N-BENZYLAMINES TO C60.
Suk Hyun Lim,1 Dae Won Cho,1* and Patrick S. Mariano2*
1Department of Chemitry, Yeungnam University, Gyeongsan, Gyeongbuk
2
Korea. Department of Chemistry and Chemical Biology, University of New
Mexico, Albuquerque, New Mexico 87131, USA; E-mail: dwcho00@yu.ac.kr,
mariano@unm.edu
Abstract
–
Photoaddition reactions of fullerene C60 with N--
which contain various
trimethylsilyl-N-carboxymethyl-N-benzylamines,
para-substituents, were explored in order to evaluate factors governing
efficiencies of this potentially useful method for preparing functionalized
fullerene derivatives. Observations made in this study show that two reaction
pathways are followed in these photoreactions. The first involves initial formation
of -trimethylsilyl-aminium radicals and the C60 anion radical by SET from the
amines to the triplet excited state of C60. This step is followed by desilylation to
produce -amino radicals. Coupling of these radicals with the anion radical of C60
followed by protonation or with the hydrofullerene radical generated by
protonation of the anion radical of C60 then produces aminomethyl-
3
1,2-dihydrofullerenes. When limited amounts of O2 are present in the reaction
medium, fulleropyrrolidines are generated in low yields by a competitive pathway
involving formation of singlet oxygen, which undergoes sequential H-atom
abstractions from the N--trimethylsilyl-N-carboxymethyl-N-benzylamines to
produce azomethine ylide intermediates. Dipolar cyloaddition of the ylides to C60
then produces fulleropyrrolidines. Photoreactions of the C60 and the amines in the
3
presence of high O2 concentrations exclusively produce fulleropyrrolidine. In
addition, the results show that photoreactions of non-silicon substituted,
N-methyl-N-carboxymethyl-N-benzylamines with C60 form fulleropyrrolidines

independent of the concentration of 3O2 present in the media.
INTRODUCTION
Thermal and photochemical reactions of fullerenes have been broadly explored in order to develop
methods to prepare novel substituted fullerenes that can potentially serve as unique electron accepting
materials.1-6 The most common approaches employed for the preparation of these substances involve
1,3-dipolar cycloaddition,7-9 cyclopropanation10,11 and radical coupling reactions.12,13 In addition, single
electron transfer (SET) promoted photochemical reactions between fullerene and electron donating
substances14-17 also serve as useful methods for synthesizing substituted fullerenes. These reactions are
driven by the high electron affinities18 and relatively high reduction potential (3Ered(C60) = 1.14 V vs
SCE)19 of the triplet excited state of C60. Observations made in earlier studies17 show that SET promoted
photoaddition reactions take place between tertiary amines and fullerene to produce aminomethyl
substituted 1,2-dihydrofullerene derivatives. Moreover, when -trimethylsilyl substituted tertiary amines
(1, Scheme 1) are used as electron donor substrates, photoaddition reactions with C60 generate
aminomethyl-1,2-dihydrofullerenes 4 in a highly efficient manner. The mechanistic pathway operating in
these photoaddition reactions involves initial SET from the amine to the excited state of fullerene to form
the corresponding amine radical cations 2 (i.e., aminium radicals) and fullerene radical anion. Subsequent
desilylation of the formed aminium radical occurs to produce an -amino radical 3 that couples with the
fullerene radical anion (or the corresponding protonated hydrofullerenyl radical) to generate the anion
precursor 5 of the fullerene-adduct (or directly the fullerene-adduct).
Scheme 1
Recently, we observed that the efficiencies of photoaddition reactions of amines with C60 are highly
dependent on the electronic nature of the amine substrates.17 For instance, photoreactions of
deoxygenated 10% EtOH-toluene solutions containing C60 and N--trimethylsilyl-N,N-dibenzylamines

that contains electron donating substituents (e.g., Me, OMe) on the phenyl rings, take place efficiently to
form the corresponding aminomethyl substituted 1,2-dihydrofullerene adducts in modestly high yields. In
contrast, photoreactions of N--trimethylsilyl-N,N-dibenzylamines, which contain electron withdrawing
phenyl substituents (i.e., F, CF3), require longer irradiation times and produce 1,2-adducts in low
yields.17b In addition, photoreactions of deoxygenated solutions of C60 and benzylamines, which contain
electron withdrawing N-carboxymethyl groups (e.g. 6 in Scheme 2), not only require longer irradiation
times and they produce either low yields of aminomethyl-1,2-dihydrofullerene adducts (under N2 purged
10% EtOH-toluene) or fulleropyrrolidines (e.g. 7 in Scheme 2) exclusively (oxygenated 10%
EtOH-toluene).17a These results show that photoreactions of N-carboxymethyl substituted amines in the
presence of molecular oxygen take place via a pathway that involves singlet molecular oxygen (1O2)
mediated generation of azomethine ylides (e.g. 8 in Scheme 2), reactive intermediates that undergo
1,3-dipolar cyloadditions to fullerene.7-9,17
Scheme 2
The unique effects of N-carboxymethyl substituents on the nature of photochemical reactions of amines
with C60 and substituent effects on efficiencies of SET promoted photochemical reactions of C60 with
tertiary N--trimethylsilyl-N-benzylamines are interesting in that they help guide the design of methods
to prepare variously functionalized fullerenes. To gain more information about the preparative utility of
these processes, an investigation was designed to explore photochemical reactions of fullerene C60 with
electron
donating
and
withdrawing
para-phenyl
substituted
N-carboxymethyl-N--trimethylsilyl-N-benzylamines and analogs not containing trimethylsilyl groups.
The major goal of this effort was to elucidate if and how the electronic nature of the amine substituents,
the presence of -trimethylsilyl groups and photoreaction conditions affect the efficiencies and nature of
these processes. Observation made in this study, summarized below, show that two competitive
photochemical pathways are followed in these systems, one involving formation of aminium radicals by
SET from the amine to the triplet excited state of C60 followed by desilylation leading to formation of
aminomethyl-1,2-dihydrofullerenes and the other involving formation of azomethine ylides by singlet

oxygen mediated H-atom abstraction from amine followed by cycloaddition to lead to formation of
fulleropyrrolidine adducts. The relative importance of these pathways depends on both the nature of
phenyl ring substituents, the presence or absence of -trimethylsilyl groups and high concentrations of
3O2.
RESULTS AND DISCUSSION
Synthesis of N--trimethylsilyl-N-carboxymethyl-N-benzylamines. The N--trimethylsilyl-N-
carboxymethyl-N-benzylamines, 6 and 19-22, utilized in this study were readily prepared by using
substitution reactions between available N--trimethylsilyl-N-benzylamines 9-13 and ethyl bromoacetate
in the presence of K2CO3 in MeCN (Scheme 3). In addition, in order to elucidate the effect of
trimethylsilyl groups on these photoreactions, non-trimethylsilyl containing benzylamine analogs, 23-27,
were also prepared using similar processes (Scheme 3).
Scheme 3
Photoreactions
of
C60
with
N--trimethylsilyl-N-carboxymethyl-N-benzylamines
and
non-trimethylsilyl containing counterparts. The yields and product distributions of photoreactions of
C60 with the silyl/non-silyl benzylamines 6 and 19-22, which have various substituents at para position of
the phenyl rings, were determined. All photochemical reactions were carried out by irradiating (450 W
Hanovia medium pressure mercury lamp and flint glass filter  > 300 nm) 10% EtOH-toluene solutions
containing C60 (0.28 mmol) and benzylamines (0.59 mmol). The photolysates were triturated with CHCl3
to recover C60 and the triturates were concentrated in vacuo to generate residues, which were subjected to
silica gel column chromatography to obtain pure photoproducts. Structural assignments to the
1
13
photoproducts were made based on analysis of H and C NMR, and UV-visible spectra, and by using
HRMS (see Experimental and Supporting data), as well as by comparing the data to those previously
reported17a for related compounds.

The results show that photoreactions of C60 with -trimethylsilyl containing benzylamines 6, and 19-22,
carried out on N2 purged solutions, generate two types of photoproducts, including
aminomethyl-1,2-dihydrofullerenes 28-32 and fulleropyrrolidines 33-37 (Scheme 4 and Table 1).
Specifically, 1 h irradiation of solutions of C60 and amines 19 and 20 (0.59 mmol) possessing electron
donating substituted (Me and OMe) phenyl rings as well as the unsubstituted analog 6, brings about high
conversion of C60 and modestly high yielding formation of the corresponding
aminomethyl-1,2-dihydrofullerenes 28-30 predominantly, along with low yielding generation of
fulleropyrrolidines 33-35 (Table 1, entries 1-3). In contrast, photoreactions of C60 with electron
withdrawing group (F and CF3) substituted benzylamines 21 and 22 (entries 4-5, Table 1) require longer
irradiation times to bring about high C60 conversions. Significantly, these reactions occur in lower yields
and they generate fulleropyrrolidnes 36 and 37 in relatively larger amounts. Furthermore, the results of
previous studies,17a showing that aminomethyl-1,2-dihydrofullerene 2817a is not converted to
fulleropyrrolidine 3317a upon prolonged photoirradiation, demonstrate that two types of adducts formed in
these photoreactions arise by independent pathways.
Scheme 4
Table 1. Products and yields of photoaddition reactions of N2 purged 10% EtOH-toluene solutions containing C60 and 6 and 19-22.
Irradiation
Entry
Amine
Conversion (%)b
Product (%)c
Time (h)
1
2
3
4
5
1
1
1
3
3
95
100
100
89
28 (68), 33 (10)
29 (69), 34 (2)
30 (70), 35 (3)
31 (57), 36 (10)
32 (40), 37 (10)
6
19
20
21
22
77

6d
1
100
28 (76), 33 (12)
6
a-Silylamines (0.56 mmol) and C60 (0.28 mmol) in 220 mL of 10% EtOH-toluene.
bConversions determined based on recovered C60. cYields of isolated products. dPrevious result (ref. 17a)
We postulated that the small yet finite amounts of O2, which are present in photoreaction mixtures that
are purged with nitrogen, are responsible for formation of the fulleropyrrolidine adducts (see below). In
order to explore this proposal, photoreaction of C60 with -trimethylsilyl benzylamine 6 was carried out
using a completely deoxygenated solution (by using a freeze-pump-thaw method). Specifically, a 10%
EtOH-toluene solution (7 mL) containing C60 (1.74 x 10-4 M) and benzylamine 6 (3.46 x 10-4 M) was
added to Schlenk flask and then subjected to a repetitive freeze-pump-thaw degassing process to remove
O2 completely. Irradiation of this solution under a N2 atmosphere was carried out for 2.5 h and the
photolysate was analyzed by using HPLC. Importantly, analysis of chromatogram showed that the
aminomethyl-1,2-difullerene adduct 28 (retention time 6.3 min) is produced exclusively and that none of
the fulleropyrrolidine 33 is formed (retention time 11.9 min) (See Supporting Data).
The effect of molecular oxygen on these processes was explored next. The results show that irradiation of
oxygenated 10% EtOH-toluene solutions containing C60 and benzylamines 6, 19-22 under the same
conditions as described above leads to exclusive formation of the corresponding fulleropyrrolidines 33-37
in modestly high yields (Table 2). Longer irradiation times are required for these photoreactions
regardless of the nature of the benzylamine substituent.
Table 2. Products and yields of photoaddition reactions of O2 purged 10% EtOH-toluene solutions containing C60 and 6 and 19-22.
Irradiation
Entry
Amine
Conversion (%)b
Product (%)c
Time (h)
1
2
2
2
2
2
4
2
4
2
89
90
90
68
85
56
81
91
33 (57)
34 (56)
35 (57)
36 (41)
36 (56)
37 (32)
37 (51)
38 (70)
6
19
20
21
21
22
22
6
3
4
5
6
7
8d
a-Silylamines (0.56 mmol) and C60 (0.28 mmol) in 220 mL of 10% EtOH-toluene.
bConversions determined based on recovered C60. cYields of isolated products. dPrevious result (ref. 17a)

To investigate the effect of the trimethylsilyl group in the amine substrates on the nature and efficiencies
of the photoreaction, nitrogen or oxygen purged 10% EtOH-toluene solutions solutions of C60 and the
non-trimethylsilyl containing benzylamines 23-27 were irradiated. The results (Scheme 5 and Tables 3
and 4) show that these photoreactions, taking place under both conditions, require longer irradiation times
and yield fulleropyrrolidine adducts 38-42 exclusively.
Scheme 5
Table 3. Products and yields of photoaddition reactions of N2 purged 10% EtOH-toluene solutions containing C60 and 23-27.
Irradiation
Entry
Amine
Conversion (%)b
Product (%)c
Time (h)
1
2
2
2
2
5
5
2
59
60
60
76
72
55
38 (37)
39 (35)
40 (38)
41 (40)
42 (42)
38 (30)
23
24
25
26
27
23
3
4
5
6d
aAmines (0.56 mmol) and C60 (0.28 mmol) in 220 mL of 10% EtOH-toluene.
bConversions determined based on recovered C60. cYields of isolated products. dPrevious result (ref. 17a)
Table 4. Products and yields of photoaddition reactions of O2 purged 10% EtOH-toluene solutions containing C60 and 23-27.
Irradiation
Entry
Amine
Conversion (%)b
Product (%)c
Time (h)
1
2
5
5
66
67
38 (35)
39 (35)
23
24

3
4
5
6
5
5
5
8
70
60
57
85
40 (42)
41 (32)
42 (32)
42 (50)
25
26
27
27
aAmines (0.56 mmol) and C60 (0.28 mmol) in 220 mL of 10% EtOH-toluene.
bConversions determined based on recovered C60. cYields of isolated products.
Effect of amine substituents and structures on photoaddition reaction efficiencies. As can be seen
from viewing the data given in Tables 1 and 2, the electronic nature of the p-phenyl substituent in
N--trimethylsilyl-N-carboxymethyl-N-benzylamines plays a surprisingly important role in governing
efficiencies of photoaddition reactions with C60. The results show that photoaddition reactions of non-
and electron-donating group substituted amine substrates take place more efficiently than those of the
electron withdrawing group substituted analogs. Moreover, it is clear that two independent processes
occur when solutions of C60 and the amines are irradiated. One produces
aminomethyl-1,2-dihydrofullerenes 28-32 and the other fulleropyrrolidines 33-37. Consequently, two
competing, mechanistically different pathways are followed in these reactions. The route leading to
1,2-dihydrofullerenes 28-32 is almost certainly initiated by SET from the amines to the triplet excited
state of C60, produced by direct excitation followed by rapid intersystem crossing.20 Because the rates of
SET from all benzylamines to the triplet excited state of C60 are predicted to be near equal to that of
diffusion control,17a,19 differences in the efficiencies of 1,2-dihydrofullerene formation need to be
associated with the rates of EtOH promoted desilylation of intermediate aminium radicals which
competes with energy wasting/efficiency diminishing back SET from the aminium radicals to the anion
radical of C60. Alternatively, the substituents could influence the rates of -amino radical coupling with
the anion radical of C60 or its protonated conjugate acid. Frankly, as discussed earlier,17b both of these
possibilities are difficult to understand because of the remoteness of the location of the substituents
relative to the centers participating in aminium radical desilylation and amino radical coupling.
In contrast, the pathway followed in fulleropyrrolidine forming photoreactions of N--trimethylsilyl-N-
carboxymethyl-N-benzylamines is more firmly understood. Specifically, this process takes place via a
route that involves singlet oxygen mediated formation of azomethine ylides that then undergo familiar7-9
dipolar cycloadditions to C60 (Scheme 2). As suggested by Foote20a earlier, the triplet excited state of C60
3
1
should undergo energy transfer to O2 to form O2 and ground-state C60, a process that competes with or
dominates over SET from the amine depending upon on the concentration of 3O2. In the manner described
by Foote,20a 1O2 then reacts with the N-carboxymethyl-N--trimethylsilyl-N-benzylamine through

sequential -hydrogen atom abstractions to form the key azomethine ylide (Scheme 2). This proposal is
helpful in explaining why fulleropyrolidines are formed in increased amounts relative to the
aminomethyl-1,2-dihydrofullerenes in photoreactions of electron withdrawing group substituted
1
3
substrates in deoxygenated solutions. In these cases, O2 is produced from small amounts of O2 present
under these conditions. Owing to the fact that aminomethyl-1,2-dihydrofullerene production is highly
inefficient in these cases, fullerpyrrolidine formation would become more competitive.
Another observation made in this effort has both preparative and mechanistic significance. As can be seen
from viewing the data in Tables 3 and 4, photoreactions of C60 with non-trimethylsilyl substituted
benzylamines require much longer irradiation times to bring about high conversions of C60. In addition,
these processes generate fulleropyrrolidines 38-42 exclusively. Of equal interest is the structural nature of
generated fulleropyrrolidines. As discussed above, azomethine ylide intermediates formed in
photoreactions of the N--trimethylsilyl-N-carboxymethyl-N-benzylamines involving the intermediacy of
1O2 arise by H-atom abstractions pathways. The nature of the cycloadducts dictates that loss of hydrogens
in these processes takes place exclusively from the trimethylsilyl and alkoxycarbonyl substituted
1
-carbons and not the benzylic position of the amines (see Scheme 2). However, in O2 promoted
reactions of the non-trimethylsilyl substituted amines H-atom abstractions occurs at the amine
alkoxycarbonyl and aryl substituted -centers exclusively to generate -amino radicals 43 and 44 and,
eventually, azomethine ylide 45 (Scheme 6).
Scheme 6
In
this
study,
photochemical
reactions
of
fullerene
C60
with
N--trimethylsilyl-N-carboxymethyl-N-benzylamines that contain various substituents at para position on
the phenyl ring were carried out. Observation made in this study show that two competitive
photochemical pathways are followed in these reactions, one involving formation of aminium radicals by
SET from the amine to the triplet excited state of C60 followed by desilylation leading to formation of
aminomethyl-1,2-dihydrofullerenes and the other involving formation of azomethine ylides by singlet
oxygen mediated H-atom abstraction from amine followed by cycloaddition to form fulleropyrrolidines.

The relative importance of these pathways depends on both the nature of phenyl ring substituents, the
presence or absence of -trimethylsilyl groups and the concentration of 3O2.
EXPERIMENTAL
1
13
General Procedure H and C NMR spectra were recorded on CDCl3 solutions and chemical shifts are
1
13
reported in parts per million relative to CHCl3 (7.24 ppm for H and 77.0 ppm for C) as an internal
standard. High resolution (HRMS) mass spectra were obtained by using a quadrupole mass analyzer and
electron impact ionization unless otherwise noted. All starting materials used in the photoreactions
derived from commercial sources. All new compounds described were isolated as oils in >90% purity (by
NMR analysis) unless noted otherwise.
N-trimethylsilyl-N-carboxymethyl-N-benzylamines 19-22. Individual solutions of N--
trimethylsilyl-N-benzylamines 10-13 (2.0 g, 9.6 mmol of 10, 2.0 g, 9 mmol of 11, 2.1 g, 9.9 mmol of 12,
and 1.5 g, 5.7 mmol of 13) in MeON (100 mL) containing K2CO3 (2.7 g, 19 mmol) and ethyl
bromoacetate (1.8 g for 10, 2.5 g for 11, 4.3 g for 12, and 1.2 g for 13) were stirred for 12 h at room
temperature and concentrated in vacuo to give residues which were triturated with CH2Cl2. The triturates
were dried and concentrated in vacuo to afford residues, which were subjected to silica gel column
chromatography (EtOAc: hexane = 1: 20) to yield 19 (1.5 g, 53%), 20 (1.9 g, 70%), 21 (2.6 g, 88%), and
22 (1.2 g, 56%).
1
19: H-NMR 0.06 (s, 9H), 1.25 (t, 3H, J = 7.2 Hz), 2.20 (s, 2H), 2.31 (s, 3H), 3.23 (s, 2H), 3.72 (s, 2H),
13
4.13 (q, 2H, J = 7.2 Hz), 7.09 (d, 2H, J = 7.8 Hz), 7.22 (d, 2H, J = 7.8 Hz); C-NMR -1.7, 14.0, 20.8,
45.3, 56.4, 59.7, 60.8, 128.6, 129.5, 135.6, 136.3, 170.8; HRMS (EI) m/z 293.1812 (M, C16H27NO2Si
requires 293.1811).
1
20: H-NMR 0.05 (s, 9H), 1.24 (t, 3H, J = 7.2 Hz), 2.17 (s, 2H), 3.21 (s, 2H), 3.67 (s, 2H), 3.77 (s, 3H),
13
4.12 (q, 2H, J = 7.2 Hz), 6.82 (d, 2H, J = 8.7 Hz), 7.24 (d, 2H, J = 8.7 Hz); C-NMR -1.5, 14.3, 45.5,
55.1, 56.8, 59.9, 60.7, 113.5, 129.9, 131.4, 158.6, 171.4; HRMS (EI) m/z 309.1757 (M, C16H27NO3Si
requires 309.1760).
21: 1H-NMR 0.03 (s, 9H), 1.24 (t, 3H, J = 7.2 Hz), 2.15 (s, 2H), 3.22 (s, 2H), 3.69 (s, 2H), 4.12 (q, 2H, J
= 7.2 Hz), 6.97 (t, 2H, J = 8.7 Hz), 7.26-7.31 (m, 2H); 13C-NMR -1.7, 14.1, 45.3, 56.8, 59.8, 60.6, 114.8
(d, J = 83.7 Hz), 130.1 (d, J = 31.5 Hz), 135.1 (d, J = 12 Hz), 161.8 (d, J = 972.3 Hz), 171.7; HRMS (EI)
m/z 297.1562 (M, C15H24FNO2Si requires 297.1560).
22: 1H-NMR 0.04 (s, 9H), 1.25 (t, 3H, J = 7.2 Hz), 2.19 (s, 2H), 3.26 (s, 2H), 3.82 (s, 2H), 4.14 (q, 2H, J
= 7.2 Hz), 7.46 (d, 2H, J = 8.1 Hz), 7.54 (d, 2H, J = 8.1 Hz); 13C-NMR -1.7, 14.2, 45.5, 56.9, 60.1, 61.1,
125.1 (q, J = 14.7 Hz), 128.8, 143.7, 171.0; HRMS (EI) m/z 347.1527 (M, C16H24F3NO2Si requires
347.1528).

Photoreactions of C60 with Amines. Preparative photochemical reactions were conducted using an
apparatus consisting of a 450 W Hanovia medium vapor pressure mercury lamp surrounded by a glass
filter (>300 nm) in a water-cooled quartz immersion well surrounded by the solution being irradiated,
consisting of 10% EtOH-toluene solution (220 mL) containing C60 (0.28 mmol) and the amine (0.56
mmol). The solution being irradiated was purged with either nitrogen or oxygen before and during
irradiations for the time periods given below. The photolysates were triturated with CHCl3 to recover C60
and the triturates were concentrated in vacuo to generate residues, which were subjected to silica gel
column chromatography to generate the pure photoproducts.
Photoreaction of C60 with Amine 6. Formation of 28 and 33. N2 saturated condition. 1 h irradiation,
95% conversion, column chromatography (CS2: hexane = 1: 1) to yield 28 (175 mg, 68%) and 33 (27 mg,
10%). O2 saturated condition. 2 h irradiation, 88% conversion, column chromatography (CS2: hexane = 1:
1) to yield 33 (157 mg, 57%).
Photoreaction of C60+19. Formation of 29 and 34. N2 saturated condition. 1 h irradiation, 100%
conversion, column chromatography (CS2: hexane = 1: 1) to yield 29 (179 mg, 69%) and 34 (7 mg, 2%).
O2 saturated condition. 2 h irradiation, 90% conversion, column chromatography (CS2: hexane = 1: 1) to
yield 34 (158 mg, 56%).
1
29: H-NMR 1.35 (t, 3H, J = 7.2 Hz), 2.36 (s, 3H), 3.90 (s, 2H), 4.28 (q, 2H, J = 7.2 Hz), 4.48 (s, 2H),
4.74 (s, 2H), 6.99 (s, 1H), 7.17 (d, 2H, J = 7.8 Hz), 7.48 (d, 2H, J = 7.8 Hz); 13C-NMR (CDCl3+CS2) 14.4,
21.2, 55.3, 57.9, 59.4, 60.4, 67.1, 68.2, 129.1, 129.2, 135.0, 135.8, 135.9, 137.0, 139.9, 140.1, 141.4 (2C),
141.6, 141.7, 141.8, 142.1, 142.3 (2C), 143.0, 144.3, 144.5, 145.1 (3C), 145.2, 145.6, 145.9 (2C), 146.1
(2C), 146.5, 147.0 (2C), 147.1, 154.3, 154.6, 170.7; HRMS (FAB) m/z 942.1491 (M+1, C73H20NO2
requires 942.1494).
34: 1H-NMR 0.51 (s, 9H), 1.17 (t, 3H, J = 7.2 Hz), 2.40 (s, 3H), 4.17 (q, 1H, J = 7.2 Hz), 4.28 (q, 1H, J =
7.2 Hz), 4.53 (d, 1H, J = 13.2 Hz), 5.30 (d, 1H, J = 13.2 Hz), 5.37 (s, 1H), 5.43 (s, 1H), 7.23 (d, 2H, J =
13
7.8 Hz), 7.50 (d, 2H, J = 7.8 Hz); C-NMR (CDCl3+CS2) 0.7, 14.1, 21.2, 55.7, 60.6, 69.8, 76.2, 77.2,
77.8, 128.5, 129.4, 134.7, 135.5, 135.6, 135.7, 136.0, 137.1, 139.1, 139.3, 139.4, 140.0, 141.5, 141.6,
141.7, 141.8, 141.9, 142.0 (3C), 142.1 (2C), 142.3, 142.5 (3C), 142.6, 142.9, 143.0, 144.1, 144.2, 144.3,
144.4, 144.9 (2C), 145.0 (2C), 145.1 (3C), 145.3, 145.4, 145.7, 145.8 (2C), 145.9 (2C), 146.0, 146.1,
146.2, 146.5, 146.8 (2C), 152.6, 154.8, 156.4, 157.1, 170.2; HRMS (FAB) m/z 1012.1729 (M+1,
C76H26NO2Si requires 1012.1733).
Photoreaction of C60+20. Formation of 30 and 35. N2 saturated condition. 1 h irradiation, 100%
conversion, column chromatography (CS2: hexane = 1: 1) to yield 30 (186 mg, 70%) and 35 (8 mg, 3%).
O2 saturated condition. 2 h irradiation, 90% conversion, column chromatography (CS2: hexane = 1: 1) to
yield 35 (163 mg, 57%).

1
30: H-NMR 1.36 (t, 3H, J = 6.9 Hz), 3.80 (s, 3H), 3.90 (s, 2H), 4.29 (q, 2H, J = 6.9 Hz), 4.46 (s, 2H),
4.74 (s, 2H), 6.90 (d, 2H, J = 8.1 Hz), 6.97 (s, 1H), 7.50 (d, 2H, J = 8.1 Hz); 13C-NMR (CDCl3+CS2) 14.4,
55.0, 55.5, 58.0, 59.1, 60.5, 67.3, 68.2, 113.9, 130.1, 130.4, 135.9, 136.0, 139.9, 140.1, 141.5 (2C), 141.7,
141.8, 141.9, 142.2, 142.4 (2C), 143.1, 144.4, 145.2 (3C), 145.3, 145.7, 146.0 (2C), 146.2 (2C), 146.7,
147.1 (2C), 147.2, 154.3, 154.7, 159.0, 171.1; HRMS (FAB) m/z 958.1447 (M+1, C73H20NO3 requires
958.1443).
35: 1H-NMR 0.50 (s, 9H), 1.16 (t, 3H, J = 7.2 Hz), 3.84 (s, 3H), 4.19 (q, 1H, J = 7.2 Hz), 4.29 (q, 1H, J =
7.2 Hz), 4.50 (d, 1H, J = 12.9 Hz), 5.19 (d, 1H, J = 12.9 Hz), 5.36 (s, 1H), 5.44 (s, 1H), 6.96 (d, 2H, J =
13
8.7 Hz), 7.53 (d, 2H, J = 8.7 Hz); C-NMR (CDCl3+CS2) 0.7, 14.1, 55.0, 55.4, 60.7, 69.8, 76.1, 77.5,
77.8, 114.1, 129.7, 130.7, 134.8, 135.5, 135.6, 136.0, 139.1, 139.3, 139.5, 140.1, 141.6 (2C), 141.7, 141.8,
141.9, 142.0 (2C), 142.1 (2C), 142.2, 142.3, 142.5 (2C), 142.6 (2C), 142.9, 143.0, 144.1, 144.3 (2C),
144.4, 144.9, 145.0 (2C), 145.1 (3C), 145.4, 145.7, 145.8 (2C), 145.9, 146.0 (2C), 146.1, 146.3, 146.5,
146.8, 146.9152.7, 154.9, 156.4, 157.2, 159.1, 170.3; HRMS (FAB) m/z 10.28.1685 (M+1, C76H26NO3Si
requires 1028.1682).
Photoreaction of C60+21. Formation of 31 and 36. N2 saturated condition. 3 h irradiation, 89%
conversion, column chromatography (CS2: hexane = 1: 1) to yield 31 (151 mg, 57%) and 36 (29 mg,
10%). O2 saturated condition. 2 h irradiation, 68% conversion, column chromatography (CS2: hexane = 1:
1) to yield 36 (116 mg, 41%); 4 h irradiation, 85% conversion, column chromatography (CS2: hexane = 1:
1) to yield 36 (147 mg, 56%).
1
31: H-NMR 1.37 (t, 3H, J = 7.2 Hz), 3.89 (s, 2H), 4.29 (q, 2H, J = 7.2 Hz), 4.50 (s, 2H), 4.75 (s, 2H),
13
6.96 (s, 1H), 7.05 (t, 2H, J = 8.4 Hz), 7.57 (t, 2H, J = 8.4 Hz); C-NMR (CDCl3+CS2) 14.3, 55.2, 57.8,
58.8, 60.5, 67.0, 68.3, 115.3 (d, J = 84 Hz), 130.6 (d, J = 30.9 Hz), 133.7 (d, J = 12.9 Hz), 135.8 (d, J =
18 Hz), 139.8, 140.1, 141.4 (2C), 141.5, 141.7, 141.8, 142.0, 142.3 (2C), 143.0, 144.2, 144.4, 145.1,
145.2, 145.5, 145.9 (2C), 146.1 (2C), 146.4, 146.9, 147.1, 154.0, 154.3, 162.0 (d, J = 982.2 Hz), 170.4;
HRMS (FAB) m/z 946.1245 (M+1, C72H17NO2F requires 946.1243).
36: 1H-NMR 0.51 (s, 9H), 1.18 (t, 3H, J = 7.2 Hz), 4.20 (q, 1H, J = 7.2 Hz), 4.27 (q, 1H, J = 7.2 Hz), 4.55
(d, 1H, J = 13.2 Hz), 5.23 (d, 1H, J = 13.2 Hz), 5.37 (s, 1H), 5.40 (s, 1H), 7.13 (t, 2H, J = 8.7 Hz),
7.58-7.63 (m, 2H); 13C-NMR (CDCl3+CS2) 0.6, 14.1, 55.2, 60.6, 69.6, 76.1, 77.3, 77.6, 115.5 (d, J = 84.9
Hz), 129.9 (d, J = 31.2 Hz), 134.3 (d, J = 12 Hz), 134.6, 135.4 (2C), 136.0, 139.1, 139.3, 139.4, 140.0,
141.5 (2C), 141.6 (2C), 141.7, 141.8, 141.9 (2C), 142.0 (2C), 142.2, 142.4 (2C), 142.5 (2C), 142.8, 142.9,
144.0, 144.1, 144.2, 144.3, 144.7, 144.9 (2C), 145.0 (4C), 145.2, 145.6, 145.7, 145.9 (2C), 146.0, 146.1,
146.3, 146.7, 146.8, 152.4, 154.5, 156.1, 156.9, 162.1 (d, J = 980.1 Hz), 169.8; HRMS (FAB) m/z
1016.1485 (M+1, C75H23FNO2Si requires 1016.1482).

Photoreaction of C60+22. Formation of 32 and 37. N2 saturated condition. 3 h irradiation, 77%
conversion, column chromatography (CS2: hexane = 1: 1) to yield 32 (112 mg, 40%) and 37 (30 mg,
10%). O2 saturated condition. 2 h irradiation, 56% conversion, column chromatography (CS2:hexane = 1:
1) to yield 37 (96 mg, 32%); 4 h irradiation, 81% conversion, column chromatography (CS2: hexane = 1:
1) to yield 37 (141 mg, 51%).
1
32: H-NMR 1.37 (t, 3H, J = 7.2 Hz), 3.89 (s, 2H), 4.30 (q, 2H, J = 7.2 Hz), 4.63 (s, 2H), 4.79 (s, 2H),
6.99 (s, 1H), 7.63 (d, 2H, J = 8.1 Hz), 7.76 (d, 2H, J = 8.1 Hz); 13C-NMR (CDCl3+CS2) 14.3, 55.5, 57.9,
59.1, 60.7, 67.0, 68.7, 125.5 (d, J = 14.7 Hz), 129.2, 135.8, 135.9, 139.9, 140.2, 141.4, 141.5, 141.6,
141.8, 141.9, 142.1, 142.3, 142.4 (2C), 143.0, 144.3, 144.5, 145.2 (2C), 145.3, 145.5, 146.0 (2C), 146.1,
146.2, 146.4, 146.9, 147.0, 147.2, 153.9, 154.2, 170.5; HRMS (FAB) m/z 996.1210 (M+1, C73H17F3NO2
requires 996.1211).
37: 1H-NMR 0.5 (s, 9H), 1.18 (t, 3H, J = 7.2 Hz), 4.20 (q, 1H, J = 7.2 Hz), 4.28 (q, 1H, J = 7.2 Hz), 4.65
(d, 1H, J = 13.8 Hz), 5.33 (d, 1H, J = 13.8 Hz), 5.37 (s, 1H), 5.39 (s, 1H), 7.70 (d, 2H, J = 8.4 Hz), 7.78
(d, 2H, J = 8.4 Hz); 13C-NMR (CDCl3+CS2) 0.7, 14.2, 55.8, 61.0, 70.0, 76.7, 77.0, 77.7 125.7 (q, J = 14.7
Hz), 128.6, 134.7, 135.6 (d, J = 16.5 Hz), 136.2, 139.2, 139.5, 139.6, 140.2, 141.7, 141.8 (2C), 141.9,
142.0, 142.1 (2C), 142.2 (2C), 142.4, 142.6 (2C), 142.7 (2C), 143.0, 143.1, 144.2, 144.3, 144.4, 144.5,
144.8, 145.1 (2C), 145.2 (3C), 145.4, 145.8, 145.9 (2C), 146.1 (2C), 146.2, 146.5, 146.9, 147.0, 152.4,
154.6, 156.2, 156.9, 170.1; HRMS (FAB) m/z 1066.1447 (M+1, C76H23 F3NO2Si requires 1066.1450).
Photoreaction of C60+23. Formation of 38.17a N2 saturated condition. 2 h irradiation, 59% conversion,
column chromatography (CS2: hexane = 1: 1) to yield 38 (96 mg, 37%). O2 saturated condition. 5 h
irradiation, 66% conversion, column chromatography (CS2: hexane = 1: 1) to yield 38 (91 mg, 35%).
Photoreaction of C60+24. Formation of 39. N2 saturated condition. 2 h irradiation, 60% conversion,
column chromatography (CS2: hexane = 1: 1) to yield 39 (91 mg, 35%). O2 saturated condition. 5 h
irradiation, 67% conversion, column chromatography (CS2: hexane = 1: 1) to yield 39 (92 mg, 35%).
1H-NMR 1.34 (t, 3H, J = 7.2 Hz), 2.34 (s, 3H), 2.87 (s, 3H), 4.35 (q, 1H, J = 7.2 Hz), 4.44 (q, 1H, J = 7.2
Hz), 5.62 (s, 1H), 6.32 (s, 1H), 7.18 (d, 2H, J = 8.1 Hz), 7.63 (d, 2H, J = 8.1 Hz); 13C-NMR (CDCl3+CS2)
14.4, 21.3, 35.0, 61.0, 70.8, 76.0, 76.8, 77.3, 129.3, 133.8, 136.0, 138.0, 139.4, 139.9 (2C), 141.4, 141.5,
141.6, 141.7, 141.9 (3C), 142.0 (2C), 142.1 (2C), 142.4, 142.5 (2C), 142.6, 144.2, 144.4, 144.5, 145.0,
145.1 (3C), 145.2, 145.3, 145.4 (2C), 145.5 (2C), 145.8 (2C), 146.0 (2C), 146.2, 146.5, 146.6, 150.8,
153.8, 155.7, 170.9; HRMS (FAB) m/z 940.1339 (M+1, C73H18NO2 requires 940.1338).
Photoreaction of C60+25. Formation of 40. N2 saturated condition. 2 h irradiation, 60% conversion,
column chromatography (CS2: hexane = 1: 1) to yield 40 (101 mg, 38%). O2 saturated condition. 5 h
irradiation, 70% conversion, column chromatography (CS2: hexane = 1: 1) to yield 40 (112 mg, 42%).
1H-NMR 1.34 (t, 3H, J = 7.2 Hz), 2.86 (s, 3H), 3.79 (s, 3H), 4.35 (q, 1H, J = 7.2 Hz), 4.44 (q, 1H, J = 7.2

Hz), 5.63 (s, 1H), 6.32 (s, 1H), 6.91 (d, 2H, J = 8.7 Hz), 7.68 (d, 2H, J = 8.7 Hz); 13C-NMR (CDCl3+CS2)
14.4, 34.8, 54.8, 60.8, 70.6, 76.1, 76.7, 77.2, 113.8, 128.7, 130.4, 135.8, 135.9, 136.1, 137.4, 139.4, 139.9
(2C), 141.4, 141.5 (2C), 141.6, 141.8 (2C), 141.9 (2C), 142.0 (3C), 142.4 (2C), 142.5, 142.8, 144.1, 145.0
(2C), 145.1 (2C), 145.3 (3C), 145.4 (2C), 145.7 (2C), 145.9 (2C), 146.0, 146.2, 146.4, 146.5, 153.7, 153.9,
155.7, 159.4, 170.5; HRMS (FAB) m/z 956.1290 (M+1, C73H18NO3 requires 956.1287).
Photoreaction of C60+26. Formation of 41. N2 saturated condition. 5 h irradiation, 76% conversion,
column chromatography (CS2: hexane = 1: 1) to yield 41 (106 mg, 40%). O2 saturated condition. 5 h
irradiation, 60% conversion, column chromatography (CS2: hexane = 1: 1) to yield 41 (85 mg, 32%).
1H-NMR 1.32 (t, 3H, J = 7.2 Hz), 2.86 (s, 3H), 4.35 (q, 1H, J = 7.2 Hz), 4.44 (q, 1H, J = 7.2 Hz), 5.63 (s,
13
1H), 6.36 (s, 1H), 7.07 (t, 2H, J = 8.7 Hz), 7.76 (t, 2H, J = 8.7 Hz); C-NMR (CDCl3+CS2) 14.3, 34.8,
60.9, 70.5, 75.7, 76.6 (2C), 115.4 (d, J = 87.6 Hz), 130.8 (d, J = 30.2 Hz), 132.5 (2C), 135.8, 136.0 (d, J =
20.7 Hz), 137.3, 139.3, 139.4, 139.9 (2C), 141.3, 141.4, 141.5, 141.7, 141.8, 141.9 (4C), 142.3, 142.4,
142.5, 142.9, 144.1, 144.2, 144.3, 144.4, 144.9, 145.0 (2C), 145.1, 145.2, 145.3 (3C), 145.4, 145.5, 145.7
(2C), 145.9 (3C), 146.0, 146.1, 146.2, 147.0, 147.2, 150.4, 153.2, 153.3, 155.4, 162.4 (d, J = 985.8 Hz),
170.5; HRMS (FAB) m/z 944.1089 (M+1, C72H15FNO2 requires 944.1087).
Photoreaction of C60+27. Formation of 42. N2 saturated condition. 5 h irradiation, 72% conversion,
column chromatography (CS2: hexane = 1: 1) to yield 42 (117 mg, 42%). O2 saturated condition. 5 h
irradiation, 57% conversion, column chromatography (CS2:hexane = 1: 1) to yield 42 (89 mg, 32%); 8 h
irradiation, 85% conversion, column chromatography (CS2:hexane = 1: 1) to yield 42 (139 mg, 50%).
1H-NMR 1.34 (t, 3H, J = 7.2 Hz), 2.87 (s, 3H), 4.36 (q, 1H, J = 7.2 Hz), 4.44 (q, 1H, J = 7.2 Hz), 5.54 (s,
1H), 6.45 (s, 1H), 7.65 (d, 2H, J = 8.4 Hz), 7.92 (d, 2H, J = 8.4 Hz); 13C-NMR (CDCl3+CS2) 14.4, 29.7,
34.9, 61.1, 70.8, 75.6, 76.8, 77.2, 125.4 (q, J = 14.7 Hz), 129.7, 136.0 (2C), 136.2, 137.3, 139.4, 139.5,
140.0, 141.2, 141.5 (2C), 141.6 (2C), 141.7, 141.8, 141.9, 142.0 (2C), 142.5 (2C), 142.6, 142.9 (2C),
143.0, 144.2, 144.3, 144.4 144.9, 145.0, 145.1 (2C), 145.2, 145.3, 45.4, 145.5, 145.8 (2C), 146.0 (2C),
146.1 (2C), 146.2 (2C), 147.2, 147.3, 150.4, 152.8, 153.0, 155.3, 170.7; HRMS (FAB) m/z 994.1052
(M+1, C73H15F3NO2 requires 994.1055).
Photoreactions of C60 with Amine 6 in a completely deoxygenate solution. A 10% EtOH-toluene
solution (7 mL) containing C60 (1.73 x 10-4 M) and amine 6 (3.46 x 10-4 M) was added to a Schlenk flask.
The flask containing the solution immersed in liquid nitrogen evacuated using a vaccum and pump for 20
min. The solution was thawed and then subjected to 3 repeated freeze-pump-thaw cycles until evolution
of gas during thawing was not observed. The flask was filled with N2 gas and then sealed. Irradiation
(>300 nm) for 2.5 h gave a photolysate that was subjected to HPLC analysis. The results show that a
single peak corresponding to aminomethyl-fullerene 28 is present in the chromatogram.

ACKNOWLEDGEMENTS
We congratulate Professor Lutz F. Tietze on the occasion of his 75th birthday. This study was supported
by a 2014 Yeungnam University Research Grant (214A380001).
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