Functionalization of [60]fullerene and of [60]fullerene monoadducts by photochemical cycloaddition of 4-methyl-1,2,4-triazoline-3,5-dione

Article abstract of DOI:10.1002/ejoc.200300297

The photoreactions of 4-methyl-1,2,4-triazoline-3,5-dione (NMTAD) with C₆₀ and with several fullerene derivatives have been studied. In general, NMTAD cycloadds to C₆₀ and to its monoadducts with closed structures in a highly regioselective [2+2] fashion at a cis-1 [6,6] double bond. Cycloadditions to azafulleroids occur by a slightly different pathway and result in partially cluster-opened bis(adducts). 1,6-Methano[60]fulleroid, however, also undergoes a [2+2+2] cycloaddition in the absence of light. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.

Full text of DOI:10.1002/ejoc.200300297

FULL PAPER
Functionalization of [60]Fullerene and of [60]Fullerene Monoadducts by
Photochemical Cycloaddition of 4-Methyl-1,2,4-triazoline-3,5-dione
Lars Ulmer,[a] Christina Siedschlag,[a] and Jochen Mattay*[a]
Keywords: Bisfunctionalization / [60]Fullerene / Photochemical cycloaddition
The photoreactions of 4-methyl-1,2,4-triazoline-3,5-dione
(NMTAD) with C60 and with several fullerene derivatives
have been studied. In general, NMTAD cycloadds to C60 and
to its monoadducts with closed structures in a highly regiose-
lective [2+2] fashion at a cis-1 [6,6] double bond. Cycloaddi-
tions to azafulleroids occur by a slightly different pathway
and result in partially cluster-opened bis(adducts). 1,6-Me-
thano[60]fulleroid, however, also undergoes a [2+2+2] cyclo-
addition in the absence of light.
( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2003)
Introduction
this report we focus on photoinduced reactions of NMTAD
with [60]fullerene and with several fullerene derivatives.
Investigations into the regioselectivity of multiple func-
tionalizations of fullerenes have revealed three aspects to
be responsible for the observed regioselectivity of twofold
additions to fullerenes.[1Ϫ4] These are enhanced frontier or-
bital coefficients, more reactive, compressed [6,6] double
bonds and the possibility of forming thermodynamically
more stable addition products and they can be related to
the characteristic cage distortion present in monoad-
ducts.[2b,3] The addition reactions to [6,6] double bonds of
1,2-monoadducts of C60 proceed with a preference for at-
tack at the e- and trans-3 bonds for sterically demanding
addends such as C(COOEt)2, and at e-, trans-3 and cis-1
for sterically less demanding addends such as imino groups.
Second functionalizations of azafulleroids proceed highly
regioselectively at the [6,6] double bond next to the imino
bridge.[5Ϫ10]
The most versatile and straightforward reactions in ful-
lerene chemistry are cycloadditions to the [6,6] double
bonds, and it is known from previous investigations that
fullerenes react as dienophiles in [4ϩ2] cycloadditions.[3]
Rubin et al., however, reported a reaction sequence, open-
ing the fullerene cage, in which a [60]fullerene derivative
acts as diene.[11] One of the most reactive dienophiles for
DielsϪAlder reactions is 4-methyl-1,2,4-triazoline-3,5-di-
one (NMTAD),[12] and Sheridan et al. have reported photo-
induced [4ϩ2] cycloadditions of NMTAD to arenes.[13] On
the other hand, NMTAD reacts with alkenes through pho-
toinduced [2ϩ2] cycloadditions to yield diazetidines.[12a] In
Results and Discussion
Our initial idea was to carry out [4ϩ2] cycloaddition re-
actions with fullerene derivatives and NMTAD, in which
the fullerenes would react as dienes. Since the cis-1 [6,6]
double bond in sterically less demanding monoadducts is
the preferred bond to be attacked, we chose as the first
fullerene compound the DielsϪAlder adduct 1 of C60 and
cyclopentadiene. The advantage of this fullerene derivative
is the reversibility of the cyclopentadiene addition on heat-
ing, so it should be possible to remove the cyclopentadiene
addend after addition of NMTAD. Furthermore, we also
investigated additions of NMTAD to the 1-functionalized
1,2-dihydro[60]fullerenes 2 and 3, since the cis-1 bond near
the hydrogen atom is not subject to any steric demand.[14]
For the preparation of the addition products 4, 5 and 6,
solutions of NMTAD and fullerene monoadducts 1, 2 and
3 in 1,1,2,2-tetrachloroethane were irradiated at 419 nm for
3Ϫ4 h (Scheme 1). Chromatography on silica gel afforded
bis(functionalized) fullerene derivatives 4, 5 and 6 in 30,
24 and 43% yields, respectively. Their compositions were
confirmed by mass spectrometry.
The 13C NMR spectra of all three products each display
60 resonances for the fullerene carbon atoms: 56 sp2 reson-
ances in the region of δ ϭ 120Ϫ150 ppm and four single-
intensity resonances assigned to sp3-hybridized fullerene
carbon atoms. Additionally, the spectra also each show two
signals for the carbonyl groups at δ ഠ 162 ppm and one
signal for the methyl group linked to the nitrogen atom.
The remaining signals are attributable to the carbon atoms
of the cyclopentadiene addend and the alkyl groups, respec-
tively.
[a]
Organische Chemie I, Fakultät für Chemie, Universität
Bielefeld,
Postfach 100131, 33501 Bielefeld, Germany
E-mail: mattay@uni-bielefeld.de
Eur. J. Org. Chem. 2003, 3811Ϫ3817
DOI: 10.1002/ejoc.200300297
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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L. Ulmer, C. Siedschlag, J. Mattay
FULL PAPER
Scheme 1. Photochemical addition of NMTAD to 1,2-dihydro[60]fullerene derivatives
1
The H NMR spectrum of 4 contains seven signals: one
singlet for the N-methyl group, two double doublets at δ ϭ
7.01 and 6.87 ppm for the olefinic hydrogen atom, two mul-
tiplets at δ ϭ 4.51 and 4.48 ppm for the bridgehead hydro-
gen atom and a broad doublet for the methylene hydrogen
atom. Because of the stronger shift of the olefinic hydrogen
signal in relation to the bridgehead hydrogen signal we re-
gard the olefinic hydrogen atom as closer to the second ad-
1
dend than the bridgehead hydrogen atom. The H NMR
spectra of 5 and 6 show, besides the signals for the addend,
hydrogen singlets at δ ϭ 6.62 and 6.33 ppm, respectively,
attributable to the fullerenyl hydrogen atom. These patterns
are indicative of C1-symmetrical tetrahydro[60]fullerene de-
rivatives. Further evidence is provided by the UV/Vis spec-
tra, which each exhibit the characteristic absorption for
[6,6] closed fullerene derivatives at λ ഠ 425 nm, typically,
however, slightly shifted to longer wavelength than in the
monoadducts.[15]
The connectivity of 6 is confirmed by a two-dimensional
NMR spectrum (heteronuclear multiple bond correlation).
The spectrum clearly shows cis-1 stereochemistry. Further-
more, the spectra indicate that the addition of NMTAD has
occurred at the cis-1 [6,6] double bond next to the alkyl
Scheme 2. Products of NMTAD addition to the isomeric monoad-
ducts 1,2- and 1,6-C61H2
group. From this structure determination we assume the bis(functionalized) [60]fullerene adduct 10 with a [5,6]
same stereochemistry for 4 and 5. closed structure and a plane of symmetry (Scheme 2). In
The 1,2-methano[60]fullerene 7 behaves similarly, ad- accord with this result, 1,6-methano[60]fulleroid 9 also re-
dition of NMTAD having been accomplished through a acts with NMTAD without irradiation; that is, in a thermal
photoinduced reaction in a [2ϩ2] fashion, also giving rise process even at room temperature, yielding the identical ad-
to a tetrahydro[60]fullerene derivative 8 (Scheme 2). The dition product 10. Alternatively, one might consider an
structure is inferred from 13C NMR spectra and compari- equilibrium between 9 and its ring-closed valence isomer,
son to the structure determination of 6, revealing C1 sym- which could undergo
metry with cis-1 regiochemistry. NMTAD to yield 10. No such equilibrium has yet been
The 1,6-methano[60]fulleroid 9 behaves quite differently reported, however, especially at room temperature.
a DielsϪAlder reaction with
1
though. The photoinduced reaction with NMTAD pro-
The structure of 10 was elucidated by 13C and H NMR
ceeds through a [2ϩ2ϩ2] cycloaddition, giving rise to a spectroscopy. Its 13C NMR spectrum consists of 35 reson-
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Functionalization of [60]Fullerene and of [60]Fullerene Monoadducts
FULL PAPER
ances. Of these, 32 can be attributed to the fullerene carbon (Scheme 3). However, the reactivity of C60 in relation to the
atoms: 30 in the sp2 region and two at δ ϭ 93.04 and monoadducts seems to be strongly decreased. Whereas 11
70.53 ppm for the sp3 carbon atoms in the fullerene frame- was obtained only in 5% yield, addition of NMTAD to the
work. The remaining three resonances are attributable to investigated dihydrofullererenes yielded 23Ϫ43%. The 13C
the carbonyl carbon atoms (δ ϭ 162.60 ppm), the methano NMR spectrum verifies the structure of 11. The spectrum
bridge (δ ϭ 30.17 ppm) and the N-methyl group (δ ϭ displays 19 resonances: 16 fullerene sp2 signals and one sp3
26.36 ppm). The appearance of the signals at δ ϭ 93.04 and signal, indicating the expected C2v symmetry. Further evi-
70.53 ppm, with intensities of two, indicate two types of dence is provided by the UV/Vis spectrum, which shows the
sp3-hybridized fullerene carbon atoms. Together with the characteristic absorption for 1,2-functionalized [60]fullerene
number of sp2 resonances, the structure is assignable as Cs- derivatives at λ ϭ 418 nm.[15]
symmetrical with four sp3 fullerene carbon atoms (i.e., both
To verify the differences in the reactions of NMTAD
the triazolanedione addend and the methano bridge are with the two isomers 1,2-C61H2 (7) and 1,6-C61H2 (9), we
connected to sp3 carbon atoms of the fullerene core). A investigated the photochemical additions of NMTAD to
[2ϩ2ϩ2] cycloaddition of NMTAD at both [6,6] double two pairs of isomeric imino[60]fullerenes: 1,2-[(4Ј-methyl-
bonds next to the methano bridge in 9 is the only possible phenylsulfonyl)aziridino][60]fullerene (12)/1,6-[(4Ј-methyl-
means by which to achieve a structure showing such a 13C phenylsulfonyl)aza][60]fulleroid (13) and 1,2-(phenylaziridi-
1
NMR spectrum. The H NMR spectrum displays a singlet no)[60]fullerene (14)/1,6-(phenylaza)[60]fulleroid (15). Solu-
at δ ϭ 3.18 ppm for the methyl hydrogen atom and a broad tions of the monoadducts and NMTAD in 1,1,2,2-tetra-
singlet at δ ϭ 1.30 ppm for the methano hydrogen atom. chloroethane were therefore irradiated at 419 nm for 1Ϫ2
Furthermore, the strong upfield shift of the methano hydro- h. In both cases Ϫ addition of NMTAD to 12 and 13 as
gen resonances in relation to 1,6-methano[60]fulleroid[16] well as to 14 and 15 Ϫ the formation of the same cycload-
indicates the triazolanedione addend to be close to the me- ducts 16 and 17, respectively, was observed (Scheme 4).
thano bridge.
The structures of 16 and 17 were confirmed by mass
In the photoinduced reaction with NMTAD, C60 shows spectrometry and by spectroscopic methods. MALDI-TOF
similar behaviour, forming the [2ϩ2] cycloadduct 11 mass spectra show the molecular ion peaks at m/z ϭ 1002
Scheme 3. Photochemical addition of NMTAD to C60
Scheme 4. Addition of NMTAD to the aziridinofullerene/azafulleroid pairs 12/13 and 14/15
Eur. J. Org. Chem. 2003, 3811Ϫ3817
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L. Ulmer, C. Siedschlag, J. Mattay
FULL PAPER
(16) and 924 (17). The 13C NMR spectra each show 31 sig- to the [3,4] double bond. However, the second pathway
nals in the sp2 region for the fullerene carbon atoms and seems to be impossible since irradiation of 12 and 14 at λ ϭ
only one resonance for sp3-hybridized fullerene carbon 419 nm in tetrachloroethane in the absence of NMTAD
atoms, but with an intensity of two. Furthermore each spec- does not produce the cluster-opened isomers 13 and 15.
trum displays one signal for the two carbonyl carbon atoms
Two reaction pathways might also be possible for the for-
and four signals each for the aromatic carbon atoms. These mation of 16 and 17 by photoinduced cycloaddition of
results indicate Cs-symmetrical structures for both adducts, NMTAD to 13 and 15: either direct addition of NMTAD
in which the two addends are perpendicular to the plane of to the [6,6] double bond in position 3,4 (route B) or a path-
symmetry. In addition, one addend must be connected to way containing three reaction steps (route A). In the latter
sp3-hybridized fullerene carbon atoms and the other one to case, a rearrangement of the azafulleroid to the correspond-
sp2-hybridized fullerene carbon atoms, indicating a combi- ing aziridinofullerene occurs first, followed by [2ϩ2] cyclo-
nation of cluster-opened and cluster-closed functionaliz- addition of NMTAD with formation of the intermediates
ation. These results are only consistent with the proposed 16a and 17a and final rearrangement of the imino bridge
structures of 16/17 in Scheme 3. We suggest, at least for the into the opened form. Two factors are consistent with the
addition of NMTAD to the 1,2-closed isomers, that re- second pathway: (i) irradiation of azafulleroids 13 and 15
arrangement must be involved at a certain stage (Scheme 4). in the presence of NMTAD yielded traces of the corre-
Two routes for the formation of 16 and 17 through pho- sponding aziridinofullerenes 12 and 14 together with the
tochemically induced cycloaddition of NMTAD to 12 and bis(functionalized) main products 14 and 17, and (ii) ir-
14 might be possible. The first possibility is addition of radiation of 13 and 15 in the absence of NMTAD exclus-
NMTAD to a cis-1 [6,6] double bond, as in the case of 1,2- ively yielded the corresponding aziridinofullerenes 12 and
dihydrofullerenes to the intermediates 16a and 17a, fol- 14.
lowed by a rearrangement of the imino bridge from the 1,2
In consideration of these observations, we assume a [2ϩ2]
to the 1,6 position (route A, Scheme 5). The second pos- cycloaddition to a cis-1 double bond followed by a re-
sibility is initial rearrangement of the imino bridge into the arrangement of the 1,2-connected imino bridge to a 1,6-
1,6 position, followed by [2ϩ2] cycloaddition of NMTAD connected bridge with azafulleroid structure for the mecha-
Scheme 5. Possible reaction pathways for addition of NMTAD to 12, 13, 14, and 15 with formation of 16 and 17
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 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Eur. J. Org. Chem. 2003, 3811Ϫ3817

Functionalization of [60]Fullerene and of [60]Fullerene Monoadducts
FULL PAPER
with a PerkinϪElmer 1600-FTIR spectrometer. UV/Vis spectra
were measured with a PerkinϪElmer Lambda 40 spectrophoto-
meter.
nism of photoinduced addition of NMTAD to the corre-
sponding isomers 12/13 and 14/15. For the azafulleroids
this means that a previous rearrangement to the corre-
sponding aziridinofullerenes must occur.
Photochemical Addition of NMTAD to 1,2-Dihydrofullerenes
Synthesis of 4Ј-Methyl-3Ј,5Ј-dioxo-1Ј,2Ј,4Ј-triazabicyclo[3.2.0]-
heptano-[6Ј,7Ј:1,2]-endonorboneno-[6ЈЈ,7ЈЈ:3,4]-1,2,3,4-tetrahydro-
[60]fullerene (4): A solution of cyclopentadieneϪC60 adduct 1
(50 mg, 0.06 mmol) and NMTAD (14 mg, 0.12 mmol) in 1,1,2,2-
tetrachlorethane (30 mL) was deoxygenated by purging with argon
and irradiated at λ ϭ 419 nm for 4 h in Pyrex tubes. The solvent
was evaporated under reduced pressure. Chromatography on silica
gel 60 first gave C60 (12 mg, 26%, eluent: toluene/cyclohexane, 1:1)
Conclusions
In agreement with previous investigations into
bis(functionalizations) of fullerenes,[1Ϫ4] photoinduced ad-
dition of NMTAD to 1,2-dihydro[60]fullerenes proceeds at
a cis-1 [6,6] double bond with formation of 1,2,3,4-tetra-
hydro[60]fullerene derivatives. NMTAD addition to 1-sub-
and then 4 (17 mg, 30%, 2nd fraction, eluent: chloroform). 1H
3
stituted 1,2-dihydrofullerenes takes place at the cis-1 double NMR (500.13 MHz, CS2/CD2Cl2, 4:1): δ ϭ 7.01 (dd, JH,H ϭ 3.0,
3
5.7 Hz; 1 H, 2ЈЈ-H or 3ЈЈ-H), 6.87 (dd, JH,H ϭ 3.2, 5.7 Hz; 1 H,
2ЈЈ-H or 3ЈЈ-H), 4.52Ϫ4.50 (m, 1 H, 1ЈЈ-H or 4ЈЈ-H), 4.49Ϫ4.47 (m,
bond next to the substituent, indicating its higher reactivity
in relation to the cis-1 double bond next to the fullerenyl
hydrogen atom. In accord with previous investigations,[3]
this double bond might have more enhanced frontier orbital
coefficients or be the more compressed cis-1 double bond.
NMTAD undergoes a [2ϩ2ϩ2] cycloaddition with the 1,6-
opened methano[60]fulleroid, achievable either by ir-
radiation or in a thermal process even at room temperature.
Surprisingly, photoinduced additions of NMTAD to iso-
2
1 H, 1ЈЈ-H or 4ЈЈ-H), 3.76 (d, JH,H ϭ 9.9 Hz; 1 H, 5ЈЈ-H), 3.34 (s,
3 H, 8Ј-H), 2.57 (dt, 2JH,H ϭ 9.9, 3JH,H ϭ 1.7 Hz, 1 H, 5ЈЈ-H) ppm.
13C NMR (125.76 MHz, CS2/CD2Cl2, 4:1): δ ϭ 161.19 and 160.06
(3Ј-C, 5Ј-C), 157.26, 150.94, 149.10, 148.77, 148.29, 148.17, 147.49,
147.41, 146.99, 146.61, 146.57, 146.54, 146.31, 146.29, 146.14,
146.10, 145.57, 144.97, 144.78, 144.76, 144.71, 144.67, 144.40,
144.32, 144.27, 144.17, 144.05, 143.99, 143.95, 143.87, 143.78,
143.63, 143.48, 143.45, 143.32, 142.88, 142.43, 142.39, 142.30,
meric iminofullerenes yield identical 1,3,4,6-functionalized 142.26, 141.79, 141.56, 140.56, 140.45, 140.34, 140.27, 138.19,
138.08, 137.49, 137.46, 136.56, 136.35, 136.04, 134.92, 127.84,
127.39, 125.48, 125.39 (56 C60 sp2 signals, 2ЈЈ-C, 3ЈЈ-C), 83.74 and
82.95 (1-C, 2-C), 73.49 and 68.71 (3-C, 4-C), 55.48 and 55.19 (1ЈЈ-
C, 4ЈЈ-C), 46.00 (5ЈЈ-C), 26.13 (8Ј-C). FT-IR (KBr): ν˜ ϭ 2921 m
(CH2), 1721 s (CϭO), 1636 m, 1508 w, 1430 m, 1379 m, 1261 m,
1097 m, 1017 m, 804 m, 696 m, 524 m cmϪ1. UV/Vis (CH2Cl2):
λmax [Ͼ 220 nm] (ε) ϭ 228 (44870), 257 (55120), 301 sh (17560),
323 sh (14530), 428 (1150) nm. MS (MALDI-TOF, pos. ion mode,
DCTB, 15 kV): m/z (%) ϭ 899 (20) [M]ϩ {calcd. 899.32}, 721 (100)
[M Ϫ C8H9N3O2].
bis(adducts) with partially opened cluster structure. Pre-
sumably, these reactions occur through [2ϩ2] cycloaddition
and one or two rearrangements, depending on the choice
of isomer used.
Experimental Section
General Remarks: The C60 used was gold grade (Hoechst,
Ն 99.4%). All reactions were performed under argon. o-Dichloro-
benzene was of purum grade (Ն 98%), toluene, carbon disulfide,
acetonitrile and 1,1,2,2-tetrachloroethane were used in per analysis
quality. Cyclohexane was used freshly distilled. Removal of all sol-
vents was carried out under reduced pressure. The solutions were
Synthesis of 4Ј-Methyl-3Ј,5Ј-dioxo-1,2,3,4-tetrahydro-1Ј,2Ј,4Ј-tri-
azabicyclo[3.2.0]heptano-[6Ј,7Ј:1,2]-3-hydroxymethyl-[60]fullerene
(5): A solution of 1-hydroxy-1,2-dihydro[60]fullerene (2) (114 mg,
0.152 mmol) and NMTAD (108 mg, 0.900 mmol) in 1,1,2,2-tetra-
chlorethane (80 mL) was deoxygenated by purging with argon and
irradiated in Pyrex tubes (10 mL) in an RPR 100 Rayonet Photoch-
˚
emical Chamber Reactor with RPR 4190 A lamps. Analytical high irradiated at 419 nm for 3 h in Pyrex tubes. The solvent was evapo-
performance liquid chromatography (HPLC) was performed on a
C18-reversed-phase column (Macherey ET 250/4 Nucleosil 100-5)
with toluene/acetonitrile (1:1.1) as liquid phase (UV/Vis detection
at 300 nm Kontron HPLC detector 432), flow 1.1 mL minϪ1
rated under reduced pressure. Chromatography on silica gel 60 first
gave traces of C60 and remaining starting material (toluene). A
change in the eluent to chloroform gave 5 (32 mg, 24%).1H NMR
(500.13 MHz, o-C6D4Cl2): δ ϭ 6.24 (s, 1 H, 4-H), 5.33Ϫ5.25 (m, 1
(Merck L-6000 pump). For preparative HPLC, a Bucky Clutcher H, 1ЈЈ-H), 5.15Ϫ5.06 (m, 1 H, 1ЈЈ-H), 3.99Ϫ3.90 (m, 1 H, 1ЈЈ-OH),
column (Regis, precolumn 50 ϫ 10.0 mm, column 250 ϫ 21.1 mm,
Bucky Clutcher I, 10 µm, 100 A), an Abimed-Gilson Spectrochrom
3.25 (s, 3 H, 8Ј-H) ppm. 13C NMR (125.76 MHz, o-C6D4Cl2): δ ϭ
161.59 and 161.39 (3Ј-C, 5Ј-C), 153.83, 149.15, 148.87, 148.31,
148.26, 148.24, 148.10, 147.25, 146.63, 146.54, 146.48, 146.19,
˚
detector (UV/Vis detection at 300 nm) and a Kontron HPLC pump
420 (flow: 10 mL minϪ1) were used. Column chromatography was 146.08, 146.03, 145.90, 145.82, 145.15, 144.83, 144.75, 144.54,
performed on silica gel (MachereyϪNagel, 63Ϫ200 µm and 40Ϫ60
µm). After isolation, products were purified by dissolving in CS2,
precipitating with n-pentane, centrifugation and decantation to re-
move the pentane-soluble components. They were finally dried un-
144.36, 144.34, 144.26, 144.19, 144.10, 144.03, 143.81, 143.73,
143.68, 143.46, 143.28, 143.08, 142.87, 142.64, 142.63, 142.30,
142.17, 141.99, 141.49, 141.10, 140.73, 140.35, 139.82, 139.28,
138.46, 137.52, 137.28, 136.80, 135.58, 135.30 (50 C60 sp2 signals),
3
1
der vacuum. Matrix laser desorption time-of-flight mass spectra 83.29 (ts, JC,H ϭ 4.36 Hz, 2-C), 82.08 (s, 1-C), 71.63 (dt, JC,H
ϭ
(MALDI-TOF) were recorded with a VoyagerTM DE instrument
149.06, JC,H ϭ 9.42 Hz, 1ЈЈ-C), 61.70 (ds, JC,H ϭ 4.94 Hz, 3-C),
3
2
1
{PE Biosystems, nitrogen laser, λ ϭ 337 nm, matrix: 2-[(2E)-3-
53.69 (td, 1JC,H ϭ 138.23, 3JC,H ϭ 3.18 Hz, 4-C), 26.56 (q, JC,H ϭ
(4-tert-butylphenyl)-2-methylprop-2-enylidene]malonodinitrile 142.45 Hz, 8Ј-C). FT-IR (KBr): ν˜ ϭ 3447 bm (OH), 2918 w, 1792
(DCTB), linear mode}. Relative intensities are given in percentages.
NMR spectra were recorded with Bruker AM 300 and DRX 500
spectrometers. Chemical shift data are reported relative to the sol-
vent peak as reference. Fourier transform IR spectra were recorded
w, 1718 s (CϭO), 1438 m, 1386 m, 1184 w, 1066 w, 525 m cmϪ1
.
UV/Vis (CH2Cl2): λmax [Ͼ 220 nm] (ε) ϭ 255 (106500), 322 sh
(31300), 425 (4600) nm. MS (ESI): m/z (%) ϭ 864 (95) [M Ϫ H]Ϫ
{calcd. 865.08}, 752 (100) [M Ϫ C3H3N3O2]Ϫ.
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L. Ulmer, C. Siedschlag, J. Mattay
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Synthesis of 4Ј-Methyl-3Ј,5Ј-dioxo-1Ј,2Ј,4Ј-triazabicyclo[3.2.0]hep- thane (20 mL). After deoxygenation by purging with argon,
tano-[6Ј,7Ј:1,2]-3-tert-butoxymethyl-1,2,3,4-tetrahydro[60]fullerene NMTAD (11 mg, 0.10 mmol) was added and the solution was
(6): A solution of 1-(tert-butoxymethyl)-1,2-dihydro[60]fullerene 3
(175 mg, 0.217 mmol) and NMTAD (300 mg, 2.65 mmol) in
1,1,2,2-tetrachlorethane (120 mL) was deoxygenated by purging
with argon and irradiated at 419 nm for 4 h in Pyrex tubes. The
solvent was evaporated under reduced pressure. Chromatography
on silica gel 60 first gave traces of C60 and remaining starting mate-
stirred at room temperature for 60 min. The solvent was evaporated
under reduced pressure. Chromatography on silica gel 60 with tolu-
ene first gave C60 (1 mg, 5%) and then 10 (10 mg, 41%, 2nd frac-
1
tion). H NMR (500.13 MHz, CS2/CD2Cl2, 3:1): δ ϭ 3.18 (s, 3 H,
3Ј-H), 1.30 (br. s, 2 H, 1ЈЈ-H) ppm. 13C NMR (125.76 MHz, CS2/
CD2Cl2, 3:1): δ ϭ 162.60 (3Ј-C, 5Ј-C), 158.10, 149.11, 148.73,
rial (toluene). A change in the eluent to chloroform gave 6 (85 mg, 147.89, 147.57, 147.38, 146.94, 146.78, 146.07, 145.64, 145.63,
1
43%). H NMR (500.13 MHz, o-C6D4Cl2): δ ϭ 6.33 (s, 1 H, 4-H),
144.59, 144.58, 144.54, 144.34, 144.24, 144.20, 144.08, 143.62,
5.14 (d, 2JH,H ϭ 8.2 Hz, 1 H, 1ЈЈ-H), 4.82 (d, 2JH,H ϭ 8.2 Hz, 1 H, 143.05, 141.76, 141.32, 141.11, 140.98, 140.77, 139.77, 138.38,
1ЈЈ-H), 3.26 (s, 3 H, 8Ј-H), 1.51 (s, 9 H, 4ЈЈ,5ЈЈ,6ЈЈ-H), ppm. 13C 138.26, 135.95, 129.13 (30 C60 sp2 signals), 93.04 (1-C, 4-C), 70.53
NMR (125.76 MHz, o-C6D4Cl2): δ ϭ 161.97 and 160.61 (3Ј-C, 5Ј-
1
1
(2-C, 3-C), 30.17 (t, JC,H ϭ 126.0 Hz; 1ЈЈ-C), 26.36 (q, JC,H
ϭ
C), 153.19, 149.15, 149.09, 148.82, 148.57, 148.34, 148.29, 148.27,
142.2 Hz; 6Ј-C). FT-IR (KBr): ν˜ ϭ 2922 s (CH2), 1722 s (CϭO),
147.55, 147.28, 146.74, 146.63, 146.61, 146.52, 146.21, 146.07, 1430 m, 1377 m, 1261 m, 1106 m, 1019 m, 800 m, 536 m cmϪ1
.
146.06, 145.97, 145.78, 145.14, 144.80, 144.75, 144.73, 144.36,
144.33, 144.19, 144.14, 144.04, 143.88, 143.79, 143.73, 143.54,
143.29, 143.23, 142.83, 142.77, 142.66, 142.36, 142.26, 142.16,
141.49, 140.93, 140.66, 140.42, 139.95, 138.90, 138.54, 138.06,
137.91, 137.57, 136.78, 136.64, 136.62 (53 C60 sp2 signals), 81.97
(2-C), 81.61 (1-C), 73.95 (3ЈЈ-C), 70.85 (1ЈЈ-C), 59.02 (3-C), 55.65
(4-C), 27.18 (4ЈЈ,5ЈЈ,6ЈЈ-C), 26.56 (8Ј-C). FT-IR (KBr): ν˜ ϭ 1727 s
(CϭO), 1511 m, 1431 m, 1381 m, 1186 m, 524 m cmϪ1. UV/Vis
(CH2Cl2): λmax [Ͼ 220 nm] (ε) ϭ 255 (97200), 322 sh (27200), 427
(4000) nm. MS (ESI): m/z (%) ϭ 920 (100) [M Ϫ H]Ϫ {calcd.
921.11}, 807 (10) [M Ϫ C3H4N3O2]Ϫ.
UV/Vis (CH2Cl2): λmax [Ͼ 220 nm] (ε) ϭ 229 (42590), 259 (48070),
323 (16150), 421 sh (1470) nm. MS (MALDI-TOF, pos. ion-mode,
DCTB, 15 kV): m/z (%) ϭ no [M]Ϫ {calcd. 847.24}, 735 (65) [MϪ
Ϫ C3H3N3O2], 721 (100) [MϪ Ϫ C4H5N3O2].
Synthesis of 4Ј-Methyl-3Ј,5Ј-dioxo-1Ј,2Ј,4Ј-triazabicyclo[3.2.0]hep-
tano-[6Ј,7Ј:1,2]-[60]fullerene (11): C60 (216 mg, 0.300 mmol) and
NMTAD (113 mg, 0.993 mmol) were dissolved in 1,1,2,2-tetrachlo-
rethane (100 mL). After deoxygenation by purging with argon, the
solution was irradiated at 419 nm for 5 h in Pyrex tubes. The sol-
vent was evaporated under reduced pressure and the residue was
dissolved in toluene (15 mL) and filtered. Chromatography of the
Synthesis of 4Ј-Methyl-3Ј,5Ј-dioxo-1Ј,2Ј,4Ј-triazabicyclo[3.2.0]hep- filtrate on silica gel 60 with toluene gave C60 (145 mg, 67%, 1st
tano-[6Ј,7Ј:1,2]-cyclopropano-[2ЈЈ,3ЈЈ:3,4]-1,2,3,4-tetrahydro[60]-
fullerene (8): 1,2-Cyclopropano[60]fullerene 7 (730 mg, 0.04 mmol)
was dissolved in 1,1,2,2-tetrachlorethane (20 mL). After deoxygen-
fraction). A change in the eluent to toluene/chloroform (4:1) gave
11 (12 mg, 5%, 2nd fraction). 1H NMR (500.13 MHz, CS2/CD2Cl2,
5:1): δ ϭ 3.47 (s, 3 H, 8Ј-H) ppm. 13C NMR (125.76 MHz, CS2/
ation by purging with argon, NMTAD (14 mg, 0.12 mmol) was ad- CD2Cl2, 5:1): δ ϭ 161.29 (3Ј-C, 5Ј-C), 147.80, 146.67, 146.45,
ded and the solution was irradiated at 419 nm for 30 min in Pyrex
tubes. The solvent was evaporated under reduced pressure. Chro-
matography on silica gel 60 with toluene/cyclohexane (1:1) first
146.32, 145.31, 144.99, 144.65, 144.50, 143.24, 143.18, 143.07,
142.78, 142.49, 141.76, 140.57, 139.84 (16 C60 sp2 signals), 86.27
(1-C, 2-C), 26.70 (8Ј-C). FT-IR (KBr): ν˜ ϭ 2923 m (CH3), 1797 m,
1728 s (CϭO), 1510 m, 1432 m, 1384 m, 1183 m, 1015 m, 968 w,
951 w, 942 w cmϪ1. UV/Vis (CH2Cl2): λmax [Ͼ 220 nm] (ε) ϭ 254
1
gave C60 (1.5 mg, 5%) and then 8 (17 mg, 30%, 2nd fraction). H
2
NMR (500.13 MHz, CS2/CD2Cl2, 4:1): δ ϭ 4.74 (d, JH,H
ϭ
2
6.7 Hz; 1 H, 1ЈЈ-H), 3.37 (s, 3 H, 8Ј-H), 3.22 (d, JH,H ϭ 6.7 Hz; 1 (97900), 318 (34200), 418 sh (2300), 456 sh (1400), 537 sh (800),
H, 1ЈЈ-H) ppm. 13C NMR (125.76 MHz, CS2/CD2Cl2, 4:1): δ ϭ 598 sh (400), 677 (150) nm. MS (MALDI-TOF, neg. ion-mode,
161.35 and 160.69 (3Ј-C, 5Ј-C), 155.56, 149.43, 149.29, 148.50, DCTB, 15 kV): m/z (%) ϭ 833 (100) [M]Ϫ {calcd. 833.02}, 720 (65)
148.42, 147.98, 147.62, 147.23, 146.87, 146.52, 146.46, 146.18,
146.13, 145.93, 145.80, 145.70, 145.66, 145.60, 145.36, 145.23,
145.04, 144.93, 144.71, 144.60, 144.53, 144.46, 144.45, 144.11,
144.06, 144.02, 143.98, 143.96, 143.79, 143.76, 143.71, 143.48,
143.46, 143.44, 143.23, 143.21, 142.92, 142.65, 142.54, 142.51,
142.27, 141.87, 141.58, 140.63, 140.60, 140.16, 140.00, 138.42,
138.09, 137.59, 137.45, 136.01 (56 C60 sp2 signals), 85.17 and 80.81
(1-C, 2-C), 58.76 and 57.87 (3-C, 4-C), 29.20 (1ЈЈ-C), 26.58 (8Ј-C).
FT-IR (KBr): ν˜ ϭ 2923 m (CH3), 1792 w, 1720 s (CϭO), 1510 m,
1430 m, 1382 m, 1261 m, 1180 m, 1097 m, 1021 m, 960 w, 798 m,
526 m cmϪ1. UV/Vis (CH2Cl2): λmax [Ͼ 220 nm] (ε) ϭ 230 (38470),
257 (49200), 316 (14890), 422 (860) nm. MS (MALDI-TOF, pos.
ion-mode, DCTB, 15 kV): m/z (%) ϭ 849 (77) [M]Ϫ {calcd.
847.24}, 735 (100) [MϪ Ϫ C3H3N3O2].
[M Ϫ C3H3N3O2]Ϫ.
Synthesis of 4Ј-Methyl-3Ј,5Ј-dioxo-1Ј,2Ј,4Ј-triazabicyclo[3.2.0]hep-
tano-[6Ј,7Ј:3,4]-1,6-[N-(6ЈЈ-methylphenylsulfonyl)]aza[60]fulleroid
(16). a) A solution of 1,2-[(4Ј-methylphenylsulfonyl)aziridino][60]-
fullerene 12 (10 mg, 0.01 mmol) in 1,1,2,2-tetrachlorethane (10 mL)
was deoxygenated by purging with argon, and NMTAD (3.5 mg,
0.03 mmol) was added. The solution was irradiated at 419 nm for
1 h in Pyrex tubes. The solvent was evaporated under reduced
pressure and the residue was dissolved in toluene (10 mL) and fil-
tered. Chromatography of the filtrate on silica gel 60 with toluene/
cyclohexane (1:1) gave 1,2-[(4Ј-methylphenylsulfonyl)aziridino][60]-
fullerene (0.5 mg, 5%, 1st fraction). A change in the eluent to
chloroform gave 16 (3 mg, 30%, 2nd fraction). b) A solution of 1,6-
[(4Ј-methylphenylsulfonyl)aza][60]fulleroid 13 (120 mg, 0.14 mmol)
in 1,1,2,2-tetrachlorethane (50 mL) was deoxygenated by purging
with argon, and NMTAD (52 mg, 0.45 mmol) was added. The
Synthesis of Addition Product 10 of 1,6-Methano[60]fulleroid and
NMTAD. a) 1,6-Cyclopropano[60]fulleroid 9 (20 mg, 0.03 mmol)
was dissolved in 1,1,2,2-tetrachlorethane (20 mL). After deoxygen- solution was irradiated at 419 nm for 2 h in Pyrex tubes. The sol-
ation by purging with argon, NMTAD (11 mg, 0.10 mmol) was
added and the solution was irradiated at 419 nm for 5 min in Pyrex
tubes. The solvent was evaporated under reduced pressure. Chro-
vent was evaporated under reduced pressure and the residue was
dissolved in toluene (20 mL) and filtered. Chromatography of the
filtrate on silica gel 60 with toluene/cyclohexane (1:1) gave C60
matography on silica gel 60 with toluene first gave C60 (1 mg, 5%) (4.7 mg, 5%, 1st fraction) and 1,2-[(4Ј-methylphenylsulfonyl)azirid-
and then 10 (9 mg, 39%, 2nd fraction). b) 1,6-Cyclopropano[60]ful- ino][60]fullerene (3 mg, 2.5%, 2nd fraction). A change in the eluent
leroid 9 (20 mg, 0.03 mmol) was dissolved in 1,1,2,2-tetrachlore- to chloroform gave 16 (34 mg, 25%, 3rd fraction). 2nd fraction of
3816
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2003, 3811Ϫ3817

Functionalization of [60]Fullerene and of [60]Fullerene Monoadducts
FULL PAPER
1
experiment a) and 3rd fraction of experiment b) are identical. H
Acknowledgments
3
NMR (500.13 MHz, CS2/CD2Cl2, 5:1): δ ϭ 7.95 (d, JH,H
ϭ
3
We gratefully acknowledge financial support by the Department of
Science and Research NRW (MSWF), the Fonds der Chemischen
Industrie (FCI) and the Innovationsfond der Universität Bielefeld.
8.2 Hz; 2 H, 4ЈЈ-H, 8ЈЈ-H), 7.30 (d, JH,H ϭ 8.2 Hz; 2 H, 5ЈЈ-H,
7ЈЈ-H), 3.62 (s, 3 H, 8Ј-H), 2.46 (s, 3 H, 9ЈЈ-H) ppm. 13C NMR
(125.76 MHz, CS2/CD2Cl2, 5:1): δ ϭ 160.11 (3ЈЈ-C, 5ЈЈ-C), 152.17,
150.43, 149.52, 148.14, 146.69, 146.50, 146.19, 146.11, 145.40,
145.31, 145.18, 144.89, 144.41, 144.14, 144.12, 143.93, 143.82,
143.64, 143.23, 142.56, 142.37, 142.05, 141.75, 141.50, 141.16,
140.57, 138.03, 137.81, 133.19, 132.03 (29 C60 sp2 signals, 3ЈЈ-C),
135.07 (6ЈЈ-C), 130.35 (5ЈЈ-C, 7ЈЈ-C), 129.57 (4ЈЈ-C, 8ЈЈ-C), 91.94 (3-
C, 4-C), 26.99 (8Ј-C), 21.73 (9ЈЈ-C). FT-IR (KBr): ν˜ ϭ 2817 m
(CH3), 1734 s (CϭO), 1654 m, 1560 m, 1508 m, 1437 m, 1360 m,
1186 m, 1168 m (SO2N), 1086 m (SO2), 705 w, 526 m cmϪ1. UV/
Vis (CH2Cl2): λmax [Ͼ 220 nm] (ε) ϭ 228 (40000), 253 (44000), 317
(15000) nm. MS (MALDI-TOF, neg. ion-mode, DCTB, 15 kV):
m/z (%) ϭ 1003 (100) [M]Ϫ {calcd. 1002.93}, 889 (40) [M Ϫ
C3H3N3O2]Ϫ.
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tano-[6Ј,7Ј:3,4]-1,6-(phenylaza)[60]fulleroid (17). a) A solution of
1,2-(phenylaziridino)[60]fullerene 14 (45.0 mg, 0.055 mmol) in
1,1,2,2-tetrachlorethane (50 mL) was deoxygenated by purging with
argon, and NMTAD (20 mg, 0.21 mmol) was added. The solution
was irradiated at 419 nm for 1 h in Pyrex tubes. The solvent was
evaporated under reduced pressure and the residue was dissolved
in toluene (10 mL) and filtered. Chromatography of the filtrate on
silica gel 60 with toluene/chloroform (3:1) gave 1,2-(phenylaziridin-
o)[60]fullerene (8 mg, 18%, 1st fraction) and a mixture of 17 and
traces of by-products (35 mg, 2nd fraction). Repeated chromatog-
raphy by HPLC (Bucky Clutcher I, eluent toluene) gave 17 (26 mg,
51%). b) A solution of 1,6-(phenylaza)[60]fulleroid 15 (40 mg,
0.05 mmol) in 1,1,2,2-tetrachlorethane (40 mL) was deoxygenated
by purging with argon, and NMTAD (20 mg, 0.21 mmol) was ad-
ded. The solution was irradiated at 419 nm for 1 h in Pyrex tubes.
The solvent was evaporated under reduced pressure and the residue
was dissolved in toluene (20 mL) and filtered. Chromatography of
the filtrate on silica gel 60 with toluene/chloroform (3:1) gave a
mixture of C60, 1,6-(phenylaza)[60]fulleroid and 1,2-(phenylaziridi-
no)[60]fullerene (9 mg, 1st fraction) and a mixture of 17 and traces
of by-products (28 mg, 2nd fraction). Second chromatography with
HPLC (Bucky Clutcher I, eluent toluene) gave 17 (23 mg, 50%).
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B. A. Johnson, I. Lamparth, R. Lunkwitz, B. Ma, S. I. Khan,
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3246Ϫ3247.
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G. Schick, T. Jarrosson, Y. Rubin, Angew. Chem. 1999, 111,
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E. Koerner von Gustorf, D. V. White, B. Kim, D. Hess, J.
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1
The products 17 of experiment a) and b) are identical. H NMR
[12c]
Soc., Perkin Trans. 2 1975, 1325Ϫ1334.
S. M. Weinreb, R.
(500.13 MHz, CS2/CD2Cl2, 5:1): δ ϭ 7.39 (dd, 3JH,H ϭ 7.4, 3JH,H ϭ
R. Staib, Tetrahedron 1982, 38, 3087Ϫ3128. [12d] S. Grabowski,
4
3
8.6 Hz, 2 H, 4ЈЈ-H, 6ЈЈ-H), 7.25 (dd, JH,H ϭ 1.1, JH,H ϭ 8.6 Hz,
[12e]
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3
2 H, 3ЈЈ-H, 7ЈЈ-H), 7.13 (tt, JH,H ϭ 1.1, JH,H ϭ 7.4 Hz, 1 H, 5ЈЈ-
H), 2.68 (s, 3 H, 8Ј-H) ppm. 13C NMR (125.76 MHz, CS2/CD2Cl2,
5:1): δ ϭ 161.46 (3Ј-C, 5Ј-C), 158.93, 149.33, 147.45, 146.93,
146.62, 146.48, 146.23, 146.15, 145.59, 145.24, 144.79, 144.45,
144.14, 144.12, 144.07, 143.88, 143.81, 143.79, 143.64, 143.23,
143.09, 142.58, 142.39, 142.31, 141.59, 141.37, 141.31, 138.85,
138.03, 135.90, 134.76, 133.33 (31 C60 sp2 signals, 2ЈЈ-C), 129.39
(4ЈЈ-C, 6ЈЈ-C), 122.79 (5ЈЈ-C), 116.30 (3ЈЈ-C, 7ЈЈ-C), 91.90 (3-C, 4-
C), 25.99 (8Ј-C). FT-IR (KBr): ν˜ ϭ 2928 m (CH3), 1729 s (CϭO),
1600 m, 1582 m,1512 s, 1490 m, 1434 m, 1383 m, 1179 m, 1017 m,
753 m, 691 m cmϪ1. UV/Vis (CH2Cl2): λmax [Ͼ 220 nm] (ε) ϭ 254
(60200), 319 (17200), 413 sh (4800), 423 sh (3900), 453 (1200) nm.
MS (MALDI-TOF, pos. ion-mode, DCTB, 15 kV): m/z (%) ϭ 924
(100) [M]ϩ {calcd. 924.06}, 811 (39) [M Ϫ C3H3N3O2]ϩ.
Hicks, Org. Lett. 2001, 3, 3185Ϫ3187.
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Received May 15, 2003
Eur. J. Org. Chem. 2003, 3811Ϫ3817
www.eurjoc.org
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
3817