Cymantrenyl and styryl derivatives of 1-methyl[60]fullereno[c]pyrrolidine: Synthesis and electrochemical behavior

Article abstract of DOI:10.1007/s11172-007-0059-3

New cymantrenyl derivatives of 1-methyl[60]fullereno[c]pyrrolidine were obtained. According to electrochemical data, the cymantrenyl and phenyl fragments show close electron-donating effects in the presence of the strong acceptor fullerene.

Full text of DOI:10.1007/s11172-007-0059-3

Russian Chemical Bulletin, International Edition, Vol. 56, No. 2, pp. 361—363, February, 2007
361
Brief Communications
Cymantrenyl and styryl derivatives
of 1ꢀmethyl[60]fullereno[c]pyrrolidine:
synthesis and electrochemical behavior
N. V. Abramova, S. M. Peregudova, A. O. Emel´yanova, A. P. Pleshkova, and V. I. Sokolovꢀ
A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
28 ul. Vavilova, 119991 Moscow, Russian Federation.
Fax: +7 (495) 135 5085. Eꢀmail: stemos@ineos.ac.ru
New cymantrenyl derivatives of 1ꢀmethyl[60]fullereno[c]pyrrolidine were obtained. Acꢀ
cording to electrochemical data, the cymantrenyl and phenyl fragments show close electronꢀ
donating effects in the presence of the strong acceptor fullerene.
Key words: [60]fullereno[c]pyrrolidines, pyrrolidines, manganese complexes, cymantrenes,
cyclic voltammetry, the Prato reaction.
Combination of fullerene and metallocene fragments
in one molecule can lead to intramolecular transfer of
the electron density and impart interesting electroꢀ
physical and optical properties to the resulting comꢀ
pound. The best developed method of fullerene modiꢀ
fication involves cycloaddition reactions, especially
the Prato reaction yielding fullerenopyrrolidines.1,2 Curꢀ
rently known compounds of this type mainly contain
one kind of metallocene, namely, electronꢀdonating
ferrocene.2,3 The synthesis of fullerene derivatives
that would be superior in electronꢀwithdrawing effect
to fullerene C60 itself is of topical interest. Developꢀ
ment of these investigations implies introduction into
the fullerene molecule of other electronꢀwithdrawing
metallocenes, e.g., (cyclopentadienyl)manganese triꢀ
carbonyl (cymantrene). Earlier,4,5 cymantrenyl derivaꢀ
tives of fullerene have been obtained from diazoacetylꢀ
cymantrene.
Here we carried out the Prato reaction beꢀ
tween fullerene C60, sarcosine (1), and aldehydes 2a—d
(Scheme 1) and obtained new fullereno[c]pyrrolidines
containing the cymantrenyl (3a), cymantrenylvinyl (3b),
and styryl substituents (3c).
Unlike the rest of the products, 1ꢀmethylꢀ2ꢀ
styryl[60]fullereno[c]pyrrolidine (3c) readily produced a
quaternary ammonium salt upon heating with MeI in a
sealed tube for 15 h.
1
The H NMR spectrum of compound 3a at 20 °C
shows different chemical shifts for all the four protons in
the cymantrene residue. This indicates diastereotopism
(α—α´, β—β´) resulting from hindered rotation due to the
large size of the metallocene group. A similar phenomꢀ
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 349—351, February, 2007.
1066ꢀ5285/07/5602ꢀ0361 © 2007 Springer Science+Business Media, Inc.

362
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 2, February, 2007
Abramova et al.
Scheme 1
Table 1. Reduction potentials E1/2 of compounds C60 and 3a—d
in oꢀdichlorobenzene vs. the saturated calomel electrode
Comꢀ
pound
–E1/2/V
Comꢀ
pound
–E1/2/V
C60
3a
3b
0.56, 1.00, 1.45
0.83, 1.23, 1.78
0.79, 1.16, 1.69
3с
3d
0.80, 1.19, 1.74
0.82, 1.22, 1.78
When a molecular system combines fullerene with
a moderate acceptor (phenyl) or a strong acceptor
(cymantrenyl), the difference between their electronic efꢀ
fects is canceled. For instance, the reduction potentials of
compounds 3a and 3d are close to each other: both the
phenyl and cymantrenyl fragments act as electron donors
toward C60. The presence of a double bond (as in comꢀ
pounds 3b,c) slightly weakens the electronic effect.
Experimental
1
H NMR spectra were recorded on a Bruker 400 HX specꢀ
trometer in CDCl3, DMSOꢀd6, or C6D6. Electrochemical CV
studies were performed on a PIꢀ50ꢀ1 potentiostat in oꢀdichloꢀ
robenzene solution with a glassy carbon electrode (section area
2 mm2) and 0.15 M Bu4NPF6 as a supporting electrolyte; potenꢀ
tials were measured versus a saturated calomel electrode.
MALDIꢀTOF mass spectra (positiveꢀion reflectron mode,
reflectron voltage 20 mV, anthraceneꢀ1,8,9ꢀtriol matrix) were
recorded on a ReflexꢀIII mass spectrometer (Bruker Daltonics).
Samples were prepared by dissolving an analyte compound in
CHCl3 (C = 10–4—10–6 mol L–1) and mixed in the ratio 1 : 1
with a matrix solution (20 mg mL–1) in CHCl3.
enon takes place in 1ꢀmethylꢀ2ꢀphenyl[60]fullereꢀ
no[c]pyrrolidine (3d).6
A typical CV curve is shown in Fig. 1 for compound 3b
as an example. According to the presented data, this comꢀ
pound is reduced, like fullerene, in three oneꢀelectron
steps leading to stable radical anion, dianion, and radical
trianion, respectively. We compared the reduction potenꢀ
tials of compounds 3a—c in oꢀdichlorobenzene with those
of the known2 phenyl analog 3d (Table 1).
Fullerene C60 (99.9% purity) was manufactured at the G. A.
Razuvaev Institute of Organometallic Chemistry (Nizhny
Novgorod). Cymantrenecarbaldehyde (2a) was prepared accordꢀ
ing to an earlier described procedure.7
i/mA
3ꢀCymantrenylpropꢀ2ꢀenal (2b). A mixture of cymantreneꢀ
carbaldehyde (2a) (0.478 g, 2.06 mmol) and 1 M NaOH (50 mL)
was heated to 80 °C. Then acetaldehyde (0.139 mL, 2.47 mmol)
was gradually added dropwise. The reaction mixture was reꢀ
fluxed for 2.5 h. The product was isolated by column chromaꢀ
tography on SiO2 eluted with hexane—benzene (1 : 1). The yield
was 24%. 1H NMR (CDCl3), δ: 4.90—5.60 (m, 4 H, C5H4);
6.30—7.20 (m, 2 H, CH=CH); 9.60 (br.s, 1 H, CHO).
10
5
2ꢀCymantrenylꢀ1ꢀmethyl[60]fullereno[c]pyrrolidine (3a).
A
mixture of fullerene C60 (0.1 g, 0.138 mmol),
0
cymantrenecarbaldehyde (2a) (0.039 g, 0.221 mmol), and sarꢀ
cosine (1) (0.037 g, 0.414 mmol) was refluxed in toluene
(100 mL) under argon for 2 h. Column chromatography on SiO2
eluted with hexane—toluene (1 : 1) gave compound 3a
in 40% yield. Found (%): C, 86.79; H, 1.07; N, 1.37.
C71H10MnNO3. Calculated (%): C, 87.04; H, 1.09; N, 1.49. IR,
ν/cm–1: 2035, 1955 (CO). MS, m/z: 896 [M – 3 CO]+. 1H NMR
(CDCl3), δ: 3.14 (s, 3 H, NMe); 4.27 (d, 1 H, CH2, J = 9.2 Hz);
4.55, 4.95, 4.97, 5.50 (all m, 1 H each, C5H4); 4.75 (1 H,
CHCp); 4.90 (d, 1 H, CH2, J = 9.2 Hz). 13C NMR (CDCl3), δ:
224.76 (CO); 155.74, 153.58, 152.67, 152.23, 146.42, 146.35,
–0.5
–1.0
–1.5
E/V
Fig. 1. Cyclic voltammogram of compound 3b (C
=
1•10–3 mol L–1, oꢀdichlorobenzene, 0.15 M Bu4NPF6, glassy
carbon electrode, scan rate 200 mV s–1).

Cymantrenylꢀcontaining fullerenopyrrolidines
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 2, February, 2007
363
146.28, 146.16, 146.03, 145.39, 145.25, 143.11, 142.79, 142.68,
142.19, 142.16, 142.03, 141.86, 141.73, 141.62, 140.36, 140.31,
139.73, 139.22, 136.91, 136.39, 135.56 (atoms of the fullerene
cage, which are not bound to the pyrrolidine fragment); 102.3
(quaternary C atom of Cp); 87.09, 86.20 (sp3ꢀhybridized C atoms
of the fullerene cage); 79.43, 71.10, 67.91, 41.19, 29.71 (NMe).
(E)ꢀ2ꢀCymantrenylethenylꢀ1ꢀmethyl[60]fullereno[c]pyrrolꢀ
idine (3b). A mixture of fullerene C60 (0.1 g, 0.138 mmol),
3ꢀcymantrenylpropꢀ2ꢀenal (2b) (0.043 g, 0.221 mmol), and sarꢀ
cosine (1) (0.037 g, 0.414 mmol) was refluxed in toluene
(100 mL) under argon for 10 h. The course of the reaction was
monitored by TLC with hexane—toluene (1 : 1) as an eluent.
The product was isolated by column chromatography on SiO2
eluted with hexane—toluene (1 : 1). The yield of compound 3b
was 43 mg (31%). Found (%): C, 84.67; H, 1.57; N, 1.26.
for 15 h. The precipitate that formed was washed with toluene
and hexane. The yield of compound 4 was 9.3 mg (47%).
Found (%): C, 81.36; H, 2.73; N, 1.41. C72H16IN. Calcuꢀ
lated (%): C, 84.63; H, 1.58; N, 1.37. 1H NMR (DMSOꢀd6), δ:
3.68, 4.23 (both s, 3 H each, NMe); 5.74 (d, 1 H, CH2, J =
8.5 Hz); 5.93 (d, 1 H, CHC=, J = 8.5 Hz); 6.53 (d, 1 H, CH2,
J = 8.5 Hz); 7.16 (dd, 1 H, =CH, J = 13.0 Hz, J = 7.5 Hz);
7.38—7.43 (m, 4 H, =CH, Ph); 7.78 (d, 2 H, Ph, J = 8.5 Hz).
This work was financially supported by the Division of
Chemistry and Materials Sciences of the Russian Acadꢀ
emy of Sciences (Program No. 1) and the Federal Sciꢀ
ence Agency (Contract No. 02.434.11.2023).
References
C
73H12MnNO3. Calculated (%): C, 87.17; H, 1.20; N, 1.39.
1H NMR (C6D6), δ: 2.93 (s, 3 H, NMe); 4.10—4.18, 4.32—4.40
(both m, 1 H each, C5H4); 4.67—4.95 (m, 4 H, 2 H from
C5H4 + 2 H from CH2); 5.05 (s, 1 H, CH); 6.45—6.55,
6.58—6.70 (both m, 1 H each, CH=CH).
1. M. Prato and M. Maggini, Acc. Chem. Res., 1998, 31, 519.
2. D. M. Guldi, M. Maggini, G. Scorrano, and M. Prato, J. Am.
Chem. Soc., 1997, 119, 974.
1ꢀMethylꢀ(E)ꢀ2ꢀphenylethenyl[60]fullereno[c]pyrrolidine
(3c). A mixture of fullerene C60 (0.1 g, 0.138 mmol), cinnamꢀ
aldehyde (0.03 g, 0.221 mmol), and sarcosine (1) (0.037 g,
0.414 mmol) was refluxed in toluene (100 mL) under argon for
10 h. The course of the reaction was monitored by TLC with
hexane—toluene (1 : 1) as an eluent. The product was isolated
by column chromatography on SiO2 eluted with hexane—toluꢀ
ene (1 : 1). The yield of compound 3c was 36 mg (30%). 1H NMR
(CDCl3), δ: 2.68 (s, 3 H, NMe); 3.82 (d, 1 H, CH2, J = 9.2 Hz);
4.33 (d, 1 H, CHC=, J = 8.7 Hz); 4.52 (d, 1 H, CH2, J =
9.2 Hz); 6.88 (dd, 1 H, =CHCH, J = 15.8 Hz, J = 9.2 Hz); 7.00
(d, 1 H, =CHPh, J = 15.8 Hz); 7.08—7.18 (m, 5 H, Ph).
MALDIꢀTOF MS, m/z: 878 [M]+.
3. V. I. Sokolov, N. V. Abramova, N. S. Khrushcheva, and S. M.
Peregudova, Izv. Akad. Nauk, Ser. Khim., 2003, 2616 [Russ.
Chem. Bull., Int. Ed., 2003, 52, 2764].
4. M. N. Nefedova, T. V. Mukha, and V. I. Sokolov, Izv. Akad.
Nauk, Ser. Khim., 1999, 1615 [Russ. Chem. Bull., 1999, 48
(Engl. Transl.)].
5. R. Pellicciari, B. Natalini, T. V. Potolokova, M. Marinozzi,
M. N. Nefedova, A. S. Peregudov, and V. I. Sokolov, Synth.
Commun., 2003, 33, 903.
6. P. de la Cruz, A. de la Hoz, L. M. Font, F. Langa, and M. C.
PerezꢀRodriguez, Tetrahedron Lett., 1998, 39, 6053.
7. N. M. Loim, N. A. Abramova, Z. N. Parnes, and D. N.
Kursanov, J. Organomet. Chem., 1979, 168, 33.
N,NꢀDimethylꢀ(E)ꢀ2ꢀphenylethenyl[60]fullereno[c]pyrrolidiꢀ
nium iodide (4). A mixture of compound 3c (18 mg) and MeI
(6 mL) was heated in a sealed tube on a water bath (70—80 °C)
Received August 9, 2006;
in revised form December 19, 2006