Complexes between hydrogen bonded bisporphyrin tweezers and cholesterol-appended fullerenes as organogelators and liquid crystals

Article abstract of DOI:10.1016/j.tet.2009.09.107

This paper reports the gelation and liquid crystal properties of a class of new complexes between zinc and copper bisporphyrin and C₆₀ derivatives. The bisporphyrins are induced by intramolecular hydrogen bonding to adopt a preorganized 'U'-sha

Full text of DOI:10.1016/j.tet.2009.09.107

Tetrahedron 65 (2009) 10182–10191
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Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Complexes between hydrogen bonded bisporphyrin tweezers and
cholesterol-appended fullerenes as organogelators and liquid crystals
,
a,
*
Ze-Yun Xiao a, Jun-Li Hou b, Xi-Kui Jiang a, Zhan-Ting Li a , Zhi Ma
*
a State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China
b Department of Chemistry, Fudan University, 220 Handan Lu, Shanghai 200433, China
a r t i c l e i n f o
a b s t r a c t
Article history:
This paper reports the gelation and liquid crystal properties of a class of new complexes between zinc
and copper bisporphyrin and C60 derivatives. The bisporphyrins are induced by intramolecular hydrogen
bonding to adopt a preorganized ‘U’-shaped conformation and therefore efficiently complex the C60
derivatives. As a result, the capacity of their mixtures to gelate alkanes is increased notably. The bis-
porphyrins themselves and their complexes with the C60 derivatives form the smectic liquid crystal
phase. However, the glassy transition temperature of the complexes decreases considerably.
Ó 2009 Elsevier Ltd. All rights reserved.
Received 21 August 2009
Accepted 29 September 2009
Available online 1 October 2009
Keywords:
Foldamer
Porphyrin
C60
Hydrogen bonding
Molecular tweezers
Organogel
Liquid crystal
1. Introduction
two-component functional entities. We herein describe that such
kind of new complexes not only gelate hydrocarbons, but also form
The self-assembly of well-defined architectures may be induced
by the selective association of molecular components through
discrete noncovalent interactions. In this context, supramolecular
organogelators and liquid crystals have received considerable in-
terest due to their potential applications as biomedical, optical, and
electronic materials.1,2 It is well established that porphyrins and
fullerenes form stacking complexes.3 Such an interaction has been
used to construct several classes of supramolecular organogels4 and
liquid crystals5 from two discrete components that have a single
porphyrin or fullerene unit. Although a number of porphyrin
tweezers have been reported to display increased capacity to
complex fullerene or its derivatives,6 their possibility of forming
supramolecular gels or liquid crystals has not been reported. We
previously reported the self-assembly of a class of hydrogen
bonding-driven foldamer-based porphyrin receptors that exhibit
remarkably high binding affinity for C60 and its derivatives.7 Con-
sidering that C60 can be readily modified with discrete functional-
ized units, such as the cholesterol unit, a typical moiety that
facilitate the formation of organogels and liquid crystals,8,9 we
became interested in exploring the possibility of developing novel
liquid crystals.
2. Results and discussion
Five new hydrogen bonding-driven preorganized bisporphyrin
receptors H41, Zn21, Cu21, H42, and Zn22 were designed and pre-
pared, which bear four nonpolar aliphatic chains or four polar oli-
goglycol chains. The long side chains were expected to tune their
solubility and assembling behavior in solvents of different polarity.
Compounds 3–6, which bear different side chains, were prepared as
the guest molecules. Compounds 5 or 6 are introduced with one or
two cholesterol units, which have been revealed efficient to induce
the formation of organogels and liquid crystals.8,9
The synthetic route for H41, Zn21, and Cu21 is shown in Scheme 1.
Thus, porphyrin 10 was first prepared in 5% yield from the reaction
of 7, 8 and 9 in refluxing propanoic acid and then hydrolyzed to 11.
With this acid available, 13 was prepared from the palladium-
catalyzed hydrogenation of 12. This diamine was then coupled with
11 to give H41 in 49% yield. Treatment of H41 with zinc acetate and
cupric acetate in methanol and dichloromethane gave rise to Zn21
and Cu21 in 80% and 91% yields, respectively. For the synthesis of
H42 and Zn22 (Scheme 2), compound 16 was first prepared from the
reaction of 14 and 15 in hot DMF. Its reaction with 8 and 9 in
refluxing propanoic acid gave porphyrin 17 in 9% yield, which was
* Corresponding authors. Tel.: þ86 21 54925122; fax: þ86 21 64166128.
E-mail address: ztli@mail.sioc.ac.cn (Z.-T. Li).
0040-4020/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2009.09.107

Z.-Y. Xiao et al. / Tetrahedron 65 (2009) 10182–10191
10183
OC12H25-n
R2
O
R2
O
CO2Me
C2H5CO2H
+
+
H
H
N
H
reflux, 3 h, 5%
R1O
N
N
OR1
CHO
8
CHO
9
7
O
O
OC12H25-n
CO2H
OC12H25-n
CO2Me
N
M
N
N
M
N
N
N
Ph
Ph
Ph
Ph
N
N
NaOH
NH
N
N
NH
N
pyridine/H2O
Ph
Ph
Ph
Ph
Ph
Ph
reflux,12 h
100%
HN
HN
N
H41: R1 = n-C12H25, R2 = n-C16H33, M = 2H
Zn21: R1 = n-C12H25, R2 = n-C16H33, M = Zn
Ph 11
Cu21: R1 = n-C12H25, R2 = n-C16H33, M = Cu
10
Ph
H42: R1 = (CH2CH2O)3Me, R2 = (CH2CH2O)4Me, M = 2H
Zn22: R1 = (CH2CH2O)3Me, R2 = (CH2CH2O)4Me, M = Zn
n-C16H33
O
OC16H33-n
NO2
H2 (1 atm), Pd-C(10%)
THF/MeOH, r.t., 24 h
O2N
12
n-C16H33
O
OC16H33-n
NH2
11, EDCI, DMAP
H41
CH2Cl2, r.t, 30 h, 49%
H2N
13
O
O
Zn(OAc)2, CH2Cl2/MeOH
r.t., 10 h, 80%
OR1 OR2
H41
H41
Zn21
Cu21
3: R1 = R2 = n-C16H33
4: R1 = R2 = (CH2CH2O)4Me
5: R1 = n-C16H33, R2 = Chol
6: R1 = R2 = Chol
Cu(OAc)2, CH2Cl2/MeOH
r.t., 20 h, 91%
Scheme 1. Synthesis of compounds H41, Zn21 and Cu21.
O
chol =
O
OH
O(CH2CH2O)3Me
CO2Me
then hydrolyzed with sodium hydroxide to afford 18 in 82% yield.
With 18 available, 21 was prepared from the reaction of 19 and 20 in
26% yield and further hydrogenated to give 22. This diamine was
then coupled with 18 in DMF to produce H42 in 19% yield. Treatment
of 19 with zinc acetate in methanol and dichloromethane generated
Zn22 in 89% yield. The synthesis of compounds 3–6 was straight-
forward and is shown in Scheme 3.
CO2Me
TsO(CH2CH2O)3Me (15)
K2CO3, DMF, 90 °C
17 h, 92%
14
CHO
16
CHO
O(CH2CH2O)3Me
CO2Me
Previous investigation revealed that similar zinc porphyrin
tweezers and C60 or its derivatives form 1:1 complexes.7a To evaluate
the complexing stability of the new compounds, UV–vis titration
experiments were carried out for complex Zn21$3 in n-hexane,
chloroform and 1,2-dimethoxyethane.7a The association constants
were determined to be 1.3ꢀ104, 3.1ꢀ103 and 2.3ꢀ103 Mꢁ1, re-
spectively, which are comparable to those of the previously reported
complexes,7a although it was reported that the complex may become
less stable in polar solvent.10 Because the complexes of Zn21 and Cu21
with 3, 5, and 6 exhibit a great capacity to gelate alkanes, especially
decalin (Table 1, vide infra), the association constants of the corre-
sponding 1:1 complexes Zn21$3, Zn21$5, Zn21$6, Cu21$3, Cu21$5, and
Cu21$6 in decalin were also determined. The values are 1.4ꢀ104,
1.3ꢀ104, 8.9ꢀ103, 1.3ꢀ104, 1.0ꢀ104, and 7.8ꢀ103 Mꢁ1, respectively,
indicating that both zinc and copper porphyrin strongly complex the
C60 derivatives.
NH
N
N
8, 9, EtCO2H
Ph
Ph
NaOH
reflux, 4 h, 9%
pyridine/H2O
HN
reflux, 16 h, 82%
17
18
Ph
Cl
Cl
Me(OCH2CH2)4ONa (20)
THF, r.t., 6 h, 26%
O2N
NO2
19
H2 (1 atm)
Pd-C(10%)
Me(OCH2CH2)4O
O(CH2CH2O)4Me
THF/MeOH, r.t., 22 h
O2N
NO2
21
Me(OCH2CH2)4O
O(CH2CH2O)4Me
18, HATU, DIEA
The gelation behaviors of the single and 1:1 samples in different
solvents were evaluated. The samples did not gelate benzene,
dichloromethane, chloroform or THF. However, porphyrins Zn21
and Cu21 themselves and most of their complexes with 3, 5, and 6
gelated alkanes, including decalin, n-decane, cyclohexane and n-
hexane. Four complexes also partially gelate toluene. The results are
DMF, r.t., 24 h, 19%
22
H2N
NH2
Zn(OAc)2, CH2Cl2/MeOH
r.t, 10 h, 89%
H42
Zn22
Scheme 2. Synthesis of compound Zn22.

10184
Z.-Y. Xiao et al. / Tetrahedron 65 (2009) 10182–10191
Compounds H41, H42, Zn22, 3–6 did not gelate any solvents, while
C60, I2
O
O
+
DBU, toluene
Zn21 and Cu21 were able to partially gelate most of them. Adding
1 equiv of 3 to the systems of Zn21 in decalin, n-decane or cyclo-
hexane did not increase the gelation capacity. However, the mixture
in n-hexane could partially gelate the solvent because their com-
plexation caused the solubility of Zn21 to increase considerably.
Similar result was also displayed for the mixture of 3 and Cu21 in n-
hexane. Addition of 3 promoted the gelation of Cu21 in decalin and
cyclohexane. As a result, stable organogels could be formed. A
comparison of the results of Zn21 and Cu21 with those of their
mixtures with 5 and 6 also shows that the complexes were generally
more efficient than Zn21 and Cu21 in gelation, while the complexes
of Cu21 were even more efficient than those of Zn21.11 Control ex-
periments revealed that simple Zn or Cu porphyrin, like that of 10, or
their mixtures with 3, 5, and 6 did not gelate any solvents. Therefore,
the increase of the capacity of the above mixtures in gelating al-
kanes should be attributed to the formation of stable complexes as
well as the appended cholesterol moiety. We may expect that the
complexation would promote the parallel arrangement of the two
porphyrin units of Zn21 and Cu21 and thus facilitate their ordered
stacking. The long hexadecyl and cholesterol units in the C60 de-
rivatives should also contribute significantly. The former should
increase the van der Waals interaction between stacking complexes
to promote the formation of an entangled structure, while the latter
is well known to aggregate to induce the gel state. For all the cases, 4,
Zn22, their complex and those with others did not gelate the al-
kanes, which may be rationalized by considering that their polar
oligoglycol chainwould self-coil in alkanes and thus did not help the
formation of an entangled structure.
3
n-C16H33
O
OC16H33-n
r.t, 4 h, 37%
23
TsOH (cat.)
O
O
benzene, reflux
Me(OCH2CH2)4OH
25
HO
OH
12 h, 97%
24
C60, I2
O
O
DBU, toluene
4
Me(OCH2CH2)4O
O(CH2CH2O)4Me
r.t, 4 h, 43%
26
HOCH2CO2R (28)
EDCI, DMAP (cat.)
n-C16H33
O
OH
O
CH2Cl2, r.t., 12 h, 49%
O
O
O
O
27
O
C60, CBr4, DBU
n-C16H33
O
5
OR
toluene, r.t., 4 h, 31%
29
O
O
cholesterol
EDCI, DMAP, HOBt
HO
O
OH
OR
O
O
O
CH2Cl2, r. t, 3 d, 43%
30
O
O
O
C60, DBU, CBr4
RO
O
6
O
toluene, r. t, 4 h, 23%
31
O
R =
SEM images indicated that all the organogels formed by the above
complexes gave rise to fibrous structures. Figure 1 shows the repre-
sentative results. In contrast, the samples that did not gelate the sol-
vents did not form ordered structures (not shown). AFM images of the
gel samples of the complexes also showed the formation of extended
fibrils (Fig. 1), which were not observed for the single compounds,
including Cu21 and Zn21, even though they could partially gelate the
solvents. The size of the fibers was generally smaller that exhibited on
theSEMimagesbecauseofthesubstantiallylowerconcentrationused.
To obtain insight into the stacking pattern of the porphyrin units
in the gel state, UV–vis spectra in different states were recorded. The
results for the system of Cu21 and 5 are shown in Fig. 2. The Soret
and Q bands of Cu21 in the decalin solution occurred at 415 and
539 nm, which red-shifted to 417 and 544 nm in the partial gelation
state and to 420 and 545 nm in the gel state in the presence of
1 equiv of 5. Gelation also caused the generation of a shoulder peak
at 390 nm.12 These results supported that the porphyrin units of
Cu21 formed the J-aggregation in the gel state.13 Similar red shifting
(by 2 and 5 nm) was also observed for the Soret band of Zn21 in the
the partial gel state (10 mM) and the partial gel state (10 mM) in the
presence of 1 equiv of 5 (not shown). In addition, it also generated
a shoulder peak at 405 nm. These results indicate that the porphyrin
units of Zn21 might also undergo the J-aggregation in the gel state.
Previous study indicated that the complexation of similar pre-
organized bisporphyrin receptors for C60 derivatives that bear
a chiral histidine unit caused the generation of the supramolecular
chirality in the solution of chloroform or toluene.7a Circular di-
chroism (CD) investigation showed that this supramolecular chi-
rality transfer also occurred in the gel of the complexes.14 For
example, the decalin gel of Cu21 and 5 gave rise to a negative Cotton
effect at 382 nm and a positive Cotton effect at 418 nm, which was
close to the Soret band absorption of the porphyrin unit and might
be attributed to the latter, while that of Cu21 and 6 exhibited
a positive Cotton effect at 418 nm. These signals were similar in
shape to those observed for the same samples in solution, sug-
gesting that the complexes adopted the identical binding patterns.
The complexes of Zn21 with 5 and 6 in decalin also exhibited the
Scheme 3. Synthesis of compounds 3–6.
Table 1
The gelation results of compounds 1–6 and their 1:1 complexes for alkanesa,b
Sample
Decalin
n-decane
Cyclohexane
n-hexane
Toluene
H41
Zn21
Cu21
Zn22
3
4
5
6
S
pG
pG
S
S
S
S
S
S
S
pG
pG
S
S
S
S
S
S
P
pG
P
S
P
S
P
S
S
S
S
S
S
S
S
pG
pG
S
S
S
S
S
pG
pG
pG
Zn21/3
Zn21/4
Zn21/5
pG
G
pG
pG
G (30)
pG
pG
pG
S
S
pG
G (20)c
G (28)
G (20)
G (25)
G (26)
pG
Zn21/6
pG
pG
P
pG
Cu21/3
Cu21/4
Cu21/5
pG
G (33)
pG
P
pG
S
S
pG
pG
pG
G (18)
G (25)c
G (28)d
G (40)
G (30)
Cu21/6
G (20)c
G (26)
S
S
S
S
G (27)c
G (30)d
P
pG
G (45)
G (35)
Zn22/3
Zn22/4
Zn22/5
Zn22/6
P
P
P
P
S
S
S
S
P
P
P
P
S
S
S
S
a
G¼gel; pG¼partial gel; P¼precipitate; S¼solution; the tested concentration is
20 mM.
b
The data in the parenthesis are the lowest concentration for forming a gel.
c
At 0 ꢂC.
At 10 ꢂC.
d
shown in Table 1. Generally, all the compounds and their 1:1 com-
plexes had a low solubility in n-hexane. The gelation behavior in
decalin, n-decane and cyclohexane has several tendencies.

Z.-Y. Xiao et al. / Tetrahedron 65 (2009) 10182–10191
10185
Figure 1. SEM images (20 mM) of a) Zn21/5, b) Cu21/3, c) Cu21/5, d) Cu21/6; AFM images (0.1 mM) of e) Zn21/5 and f) Cu21/5. All the samples were obtained from the decalin gels or
solutions after the solvent was evaporated.
similar CD property. The CD spectra of the complexes of Cu21 with 3,
5, and 6 are provided in Fig. 3.
the molecular model of the complex, the three peaks may be
assigned to the 001, 010, and 002 plane diffractions, which also
suggest that the complex shows a smectic phase.15 The sample of
Zn21 and 6 displayed no 002 plane diffractions and the peaks for the
001 and 010 plane diffractions broadened (Fig. 3b), indicating a less
ordered alignment. The sample of Cu21 and 5 displayed all the three
diffractions (Fig. 3c), suggesting that the complexes of the two metal
porphyrins with 5 had a similar stacking pattern. The sample of Zn21
and 5 also gave rise to a broad halo at ca. 4.4 nm, which can be
assigned to the molten chains with the liquid-like order.16 Similar
peak of the samples of Zn21 and 6 and Cu21 and 5 was considerably
weak, reflecting the low order of the molten chains.
The liquid crystal behaviors of the complexes were then studied
by the powder X-ray diffraction (PXRD). The experiments were
conducted on both pristine and xerogel samples at 80 ꢂC, at which all
complexes formed liquid crystal phase, as revealed by the differential
scanning calorimetry (DSC) experiments (Table 2, vide infra). Both
samples exhibited similar results. The representative results of the
pristine samples are shown in Fig. 4, while those of the xerogels are
provided in ESI. The mixture of Zn21 and 5 displayed three main
Bragg diffractions at 2
d spacings of 2.18, 1.38, and 1.05 nm, respectively (Fig. 3a). Based on
q
¼4.1, 6.3, and 8.4ꢂ, which corresponded to the

10186
Z.-Y. Xiao et al. / Tetrahedron 65 (2009) 10182–10191
Table 2
Thermo properties of porphyrins and fullerene derivatives
2.0
1.5
1.0
0.5
0.0
Sample
Phase-transition behaviorsa,b
H41
Gl
Gl
Gl
45
64
54
SmC
SmC
SmC
140
164
167
I
I
I
Zn21
Cu21
3
5
6
No LC phase
No LC phase
No LC phase
H41/3
H41/5
H41/6
Zn21/3
Zn21/5
Zn21/6
Cu21/3
Cu21/5
Cu21/6
10
Gl
Gl
Gl
Gl
Gl
Gl
Gl
Gl
Gl
40
43
43
46
51
50
36
47
52
Cr
Sm
Sm
Sm
SmC
SmC
SmC
SmC
Sm
124
130
130
131
140
160
74
153
150
I
I
I
I
I
I
I
Sx
I
150
I
350
400
450 500
Wavelength (nm)
550
600
Sm
182
I
10/3
10/5
10/6
No LC phase
No LC phase
No LC phase
Figure 2. UV–vis spectra of Cu21 in decalin (solid line: 2 mM, solution; dashed line:
20 mM, partial gelation) and Cu21/5 (1:1, 20 mM) (dotted line: gel).
a
The data are transition temperatures (ꢂC).
Gl: glassy; SC: smectic C; Sm: unidentified smectic phase; I: isotropic; Cr: crys-
The liquid crystal behaviors of the single compounds and their
1:1 mixtures were further investigated by polarized light micros-
copy (PLM). The results are provided in Table 2 and the PLM results
of H41, Cu21 and its mixtures with 5 and 6 are presented in Fig. 5. It
was found that C60 derivatives 3, 5, and 6 themselves did not form
liquid crystal phase, even though several C60-cholesterol blends
were reported to display such a capacity,17 while bisporphyrins H41,
Zn21, and Cu21 all exhibited an SmC liquid crystal phase with the
glassy transition temperature at 45, 64, and 54 ꢂC,18 respectively.
The temperature was reduced considerably in the presence of
1 equiv of 3, 5, or 6, suggesting that complexation promoted the
formation of the liquid crystal phase.19 Notably, the decreases of the
transition temperature caused by 3 were generally larger than
those caused by 5 or 6, which might be attributed to the rigidity of
the cholesterol unit of 5 and 6. The SmC phase of Cu21 was
a schlieren texture (Fig. 5b), in which the porphyrin units should be
orientated on one side of the lamellar structure, while the long
aliphatic chains were located on another side. When 3 was present,
it should be embedded between the two porphyrin units, leaving
its two long chains toward the breach of the tweezers.20 The mix-
ture of Cu21 and 5 formed a dentritic texture (Fig. 5c), while the
mixture of Cu21 and 6 generated a blurred schlieren texture, pos-
sibly due to the decreased matching of the aliphatic chains of Cu21
and the cholesterol moieties of 6. The existence of cholesterol-free
3 did not change the SmC phase state, even though the mixture of
b
talline. The phase structures were assigned by comparing the microscopic textures
with reported ones.18
Cu21 and 3 displayed another Sm phase state, which started at
74 ꢂC. In contrast, the addition of 5 or 6 caused it to change to the
Sm phase state. Again, this difference may be ascribed to the rigid
(a) Counts
3600
d = 2.18 nm
d = 1.38 nm
1600
d = 1.05 nm
400
5
10
15
20
25
2
Counts
(b)
d = 2.10 nm
10000
6400
3600
1600
d = 1.40 nm
15
10
5
10
15
20
25
2
c)
Counts
6400
(c)
5
b)
d = 2.10 nm
a)
d = 1.40 nm
0
d = 1.05 nm
3600
1600
-5
350
400
Wavelength (nm)
450
500
5
10
15
20
25
2
Figure 3. CD spectra of Cu21 (20 mM) in the presence of 3 (20 mM) (dashed line), 5
(20 mM) (dotted line) and 6 (20 mM) (solid line). All were obtained by sandwiching
the samples with two quartz plates.
Figure 4. Powder XRD diagrams of the pristine samples, obtained from the solution of
chloroform (35 mM), of (a) Zn21/5 (1:1), (b) Zn21/6 (1:1), and (c) Cu21/5 (1:1) at 80 ꢂC.

Z.-Y. Xiao et al. / Tetrahedron 65 (2009) 10182–10191
10187
Figure 5. Polarizing light microscopy textures of (a) H41 (80 ꢂC), (b) Cu21 (80 ꢂC), (c) Cu21/5 (1:1, 80 ꢂC), (d) Cu21/6 (1:1, 80 ꢂC) (these samples were the dry assemblies prepared
from the decalin solution and were sandwiched by two glass plates), (e) Cu21 (120 ꢂC), (f) Cu21/5 (120 ꢂC), (g) Cu21 (150 ꢂC), and (h) Cu21/5 (150 ꢂC) (these samples were prepared
from their solution in chloroform). All images were obtained by slow cooling of the isotropic melts (ca. 1 ꢂC/min).

10188
Z.-Y. Xiao et al. / Tetrahedron 65 (2009) 10182–10191
R
2
R
2
R
TOF spectra were obtained on Voyager-DE STR or IonSpec 4.7 Tesla
2
O
O
O
OR
H
OR
H
2
FTMS spectrometer. UV–vis spectra were recorded on a CARY 100
spectrometer. For the high concentration measurement, two quartz
plates were used to sandwich a thin layer of the samples. Circular
dichroism spectra were recorded on a J810 CD spectrometer. Ele-
mental analysis was carried out at the SIOC analytical center. AFM
pictures were obtained in the ‘tapping’ mode on a multimode SPM
system equipped with a Nanoscope IV controller. SEM images were
obtained with a JEOL model JSM-6390LV operating at 5 kV. PLM
images were obtained on an Olympus BX51 polarizing microscope
equipped with a Linkam LTS350 hot stage. The heating rate was
1 ꢂC/min, and the samples were prepared by evaporating the dec-
alin solution (20 mM). PXRD spectra were obtained on a X’Pert PRO
OR
H
2
H
2
H
R O
1
H
R O
1
R O
1
N
N
N
N
N
N
OR
OR
1
OR
1
O
1
O
O
O
O
O
N
N
N
N
N
N
P
h
P
h
P
h
M
N
M
N
M
N
Ph
Ph
N
Ph
N
N
N
N
N
N
N
N
P
h
P
h
P
h
M
M
M
Ph
Ph
Ph
N
N
N
N
N
N
Ph
Ph
Ph
O
O
O
O
OR
O
OR
Ph
O
OR
Ph
Ph
OR
R
OR
R
1
2
OR
R
1
2
3
1
2
3
3
O
O
O
OR
H
OR
H
2
OR
H
2
H
2
H
R O
H
R O
1
R O
1
1
N
N
N
N
N
N
OR
1
OR
1
OR
1
O
O
O
O
O
O
X system using monochromated Cu K
DSC data were collected using a Q10P (TA) calorimeter during the
second heating cycle (heating rate: 10 ꢂC/min).
a
(
l
¼0.1542 nm) radiation.
N
N
N
N
N
N
P
h
P
h
P
h
2.0 nm
M
N
M
N
M
N
Ph
Ph
N
Ph
N
N
N
N
N
N
N
N
P
h
P
h
P
h
M
M
M
Ph
Ph
Ph
N
N
N
N
N
N
4.1.1. Compound 10. To a stirred solution of 77a (6.96 g, 20.0 mmol)
and 8 (6.36 g, 60.0 mmol) in propanoic acid (300 mL) was added 9
(5.5 mL, 80.0 mmol) dropwise. The solution was refluxed for 3 h,
concentrated under reduced pressure and diluted with toluene
(300 mL). The organic phase was washed with aqueous sodium
bicarbonate solution (1 N, 100 mL), water (100 mLꢀ2) and brine
(100 mL) and dried over sodium sulfate. Upon removal of the sol-
vent under reduced pressure, the resulting residue was purified by
column chromatography (CS2/toluene 1:1) to give 10 as purple
solid, which was further recrystallized from dichloromethane and
methanol to afford pure product (0.91 g, 5%). 1H NMR (CDCl3):
Ph
Ph
Ph
O
O
O
O
OR
O
OR
Ph
O
OR
Ph
Ph
OR
1
OR
1
OR
3
1
3
3
Figure 6. Tentative model for the formation of the SmC phase for the 1:1 complexes
between the bisporphyrin tweezers and C60 derivatives.
cholesterol unit of 5 and 6, which was powerful to induce the phase
change. Figure 6 provides the tentative model for the formation of
the SmC phase of the above liquid crystals.
To find more evidences for the formation of the liquid crystal
mesophase, the pristine samples of Cu21 and its 1:1 complex with 5
obtained in chloroform (35 mM) were also studied at different
temperatures. Both samples did not gelate this solvent at any
concentrations. At 25 ꢂC, both samples exhibited order less struc-
tures, while at 120 and 150 ꢂC (Fig. 5e–h), they gave rise to a meso-
phase that were similar to that observed for the xerogel samples.
At the high temperature of 180 ꢂC, the samples melted to form
a film. These results further supported that within the two phase-
transition temperatures, there existed a liquid crystal mesophase.
d
8.87–8.83 (m, 8H), 8.63 (d, J¼2.4 Hz, 1H), 8.20–8.23 (m, 7H), 7.71–
7.80 (m, 9H), 7.24 (d, J¼5.7 Hz, 1H), 4.28 (t, J¼6.3 Hz, 2H), 3.91 (s,
3H), 2.02–1.98 (m, 2H), 1.63–1.60 (m, 2H), 1.26–1.53 (m, 16H), 0.90
(t, J¼6.9 Hz, 3H), ꢁ2.78 (s, 2H). 13C NMR (CDCl3):
d 167.0, 158.5,
142.2, 138.8,136.8,134.6,133.9,131.2, 127.7,126.7,120.2,118.9,118.6,
111.5, 69.4, 32.0, 29.8, 29.7, 29.5, 29.4, 26.1, 22.7, 14.1. MS (MALDI-
TOF): m/z 858 [MþH]þ. Anal. Calcd for C58H56N4O3: C, 81.28; H,
6.59; N, 6.54. Found: C, 81.38; H, 6.48, N, 6.38.
3. Conclusions
4.1.2. Compound 11. To a solution of 10 (0.43 g, 0.50 mmol) in
pyridine (40 mL) was added a solution of sodium hydroxide (1.00 g,
25.0 mmol) in water (20 mL). The solution was stirred under reflux
for 12 h, concentrated, diluted with water (10 mL), and neutralized
with hydrochloric acid (3 N) to pH¼3. The mixture was extracted
with chloroform (80 mLꢀ2). The organic phases were combined
and washed with water (100 mL) and brine (100 mL) and dried over
sodium sulfate. Upon removal of the solvent under reduced pres-
sure, the crude product was obtained as a purple solid (0.42 mg,
We have shown that complexes between hydrogen bonding-
driven preorganized bisporphyrin receptors and C60 derivatives
gelate alkanes and form smectic liquid crystals. Comparing to their
metal-free analogs, the complexes of the zinc and copper porphy-
rins exhibit increased gelation capacity. For the liquid crystal be-
havior, the complexation causes the glassy transition temperature
of the bisporphyrin to reduce considerably. The result shows that
hydrogen bonding-driven preorganization of components is a new,
efficient approach to tuning the structures and functions of su-
pramolecular entities. In the future, we will design new dipodal
components to study the possibility of tuning the functions of their
supramolecular polymers by this approach. The bisporphyrin re-
ceptors may also be appended into polymeric systems. In this way,
their capacity in gelating solvents and forming the phase of liquid
crystals may also be amplified.
100%). 1H NMR (CDCl3):
d 11.29 (br, 1H), 9.05 (s, 1H), 8.86–8.83 (m,
6H), 8.76 (d, J¼3.9 Hz, 2H), 8.32 (d, J¼8.7 Hz, 1H), 8.20 (br, 6H), 7.76
(br, 9H), 7.37 (d, J¼8.7 Hz, 1H), 4.50 (2H), 2.10–2.07 (m, 2H), 1.65–
1.61 (m, 2H), 1.26–1.45 (m, 16H), 0.92–0.89 (m, 3H), ꢁ2.80 (s, 2H).
MS (MALDI-TOF): m/z 844.7 [MþH]þ. HRMS (MALDI-TOF): Calcd for
C57H55N4O3: 843.4269. Found: 843.4248.
4.1.3. Compound 13. A mixture of 1221 (1.30 g, 2.0 mmol) and Pd–C
(10%, 0.50 g) in THF (50 mL) and methanol (50 mL) was stirred in
a flask, connected with a hydrogen balloon, at rt for 24 h. The solid
was filtrated and filtrate concentrated under vacuum to give 13 as
crude product. The compound was instable and used for the next
step without further purification.
4. Experimental section
4.1. General methods
Unless otherwise indicated, all reactions were carried out under
a nitrogen atmosphere. Starting materials were obtained from
commercial suppliers and were used without further purification.
The 1H NMR spectra were recorded on 400 or 300 MHz spec-
trometers in the indicated solvents. Chemical shifts are expressed
4.1.4. Compound H41. To
a stirred solution of 11 (0.42 g,
0.50 mmol), 13 (0.15 g, 0.25 mmol) and 4-(N,N-dimethylamino)-
pyridine (10 mg) in CH2Cl2 (100 mL) was added EDCI (0.25 g,
1.30 mmol). The mixture was stirred at rt for 30 h, then washed
with water (80 mLꢀ3) and brine (80 mL) and dried over sodium
sulfate. After removal of the solvent under vacuum, the resulting
in parts per million (
d
) using residual solvent protons as internal
7.26 ppm; DMSO: 2.49 ppm). MALDI-
standards (chloroform:
d
d

Z.-Y. Xiao et al. / Tetrahedron 65 (2009) 10182–10191
10189
residue was purified by column chromatography (petroleum ether/
CH2Cl2 1:1) to give H41 as purple solid (0.27 g, 49%). IR (KBr):
3444, 2923, 2852, 1659, 1537, 1469, 970, 800 cmꢁ1. UV–vis (deca-
lin): 419, 514, 550, 591, 649 nm. 1H NMR (CDCl3):
10.21 (s, 2H),
(5.36 g, 80.0 mmol) dropwise. The solution was stirred under reflux
for 3 h, concentrated under vacuum and dissolved in dichloro-
methane (200 mL). The organic phase was washed with saturated
sodium bicarbonate solution (100 mL), water (100 mLꢀ3) and brine
(100 mL) and dried over sodium sulfate. After removal of the solvent,
the resulting residue was purified by column chromatography
(CH2Cl2/EtOH 50:1–20:1) to give 17 as purple solid (1.01 g, 9%). 1H
n
d
9.48 (s, 1H), 9.17 (d, J¼2.4 Hz, 2H), 8.75–8.85 (m, 16H), 8.16–8.21 (m,
14H), 7.59–7.76 (m, 18H), 7.35 (d, J¼8.7 Hz, 2H), 6.68 (s, 1H), 4.46 (t,
J¼6.6 Hz, 4H), 4.16 (t, J¼6.9 Hz, 4H), 2.12–2.09 (m, 4H), 1.97–1.92
(m, 4H), 1.14–1.60 (m, 88H), 0.88–0.78 (m, 12H), ꢁ2.80 (s, 4H). 13C
NMR (CDCl3):
d
8.80–8.85 (m, 8H), 8.63 (d, J¼2.4 Hz, 1H), 8.20–8.22
NMR (CDCl3):
d
162.9, 156.7, 146.1, 142.3, 142.2, 138.4, 135.2, 134.6,
(m, 7H), 7.71–7.80 (m, 9H), 7.32 (d, J¼5.7 Hz, 1H), 4.47 (t, J¼6.3 Hz,
2H), 4.08 (t, J¼6.3 Hz, 2H), 3.90–3.93 (m, 5H), 3.70–3.78 (m, 4H), (t,
127.6, 127.5, 126.6, 126.5, 121.7, 121.3, 120.1, 119.9, 119.2, 111.2, 70.1,
69.8, 32.0, 31.9, 29.8, 29.7, 29.6, 29.5, 29.4, 29.3, 26.1, 26.0, 22.7, 22.6.
14.1,14.0. MS (MALDI-TOF): m/z 2238 [MþH]þ. HRMS (MALDI-TOF):
Calcd for C152H177N10O6: 2238.3928. Found: 2238.3847.
J¼1.8 Hz, 2H), 3.40 (s, 3H), ꢁ2.78 (s, 2H). 13C NMR (CDCl3):
d 166.6,
158.1, 142.0, 138.6, 136.7, 134.4, 131.0128.9, 128.4, 127.9, 127.6, 126.6,
120.1,119.0,118.3,111.9, 71.9, 71.8, 71.0, 70.7, 70.5, 69.6, 69.2, 58.9, 51.9.
MS (MALDI-TOF): m/z 835.6 [MþH]þ. Anal. Calcd for C53H46N4O6: C,
76.24; H, 5.55; N, 6.71. Found: C, 76.68; H, 5.61; N, 6.35.
4.1.5. Compound Zn21. A mixture of H41 (56 mg, 0.025 mmol) and
zinc acetate dihydrate (38 mg, 0.17 mmol) in dichloromethane
(15 mL) and methanol (5 mL) was stirred at rt for 20 h, concentrated
under vacuum and then diluted with chloroform (50 mL). The so-
lution was washed with water (40 mLꢀ2) and brine (40 mL) and
dried over sodium sulfate. After the solvent was removed with
a rotavapor, the residue was purified by column chromatography
(petroleum ether/CH2Cl2 1:1) to give Zn21 as purple solid (47 mg,
80%). IR (KBr): 3386, 2923, 2852, 1658, 1535, 1486, 1467, 1003,
796 cmꢁ1. UV–vis (decalin): 428, 562, 602 nm. 1H NMR (CDCl3):
4.1.9. Compound 18. To a stirred solution of 17 (0.42 g, 0.50 mmol)
in pyridine (60 mL) was added a solution of sodium hydroxide
(2.00 g, 50 mmol) in water (30 mL) slowly. The mixture was stirred
under reflux for 16 h, concentrated under vacuum, diluted with
water (30 mL) and acidified with hydrochloric acid to pH¼5. The
suspension was then extracted with dichloromethane (100 mLꢀ3).
The organic phases were combined and washed with water
(200 mLꢀ2) and brine (200 mL) and dried over sodium sulfate. After
removal of the solvent, the resulting residue was purified by column
chromatography (CH2Cl2/EtOH 20:1) to give 18 as purple solid
d
10.25 (s, 2H), 9.48 (s, 1H), 9.10 (2H), 8.83–8.94 (m, 16H), 8.10–8.21
(m, 14H), 7.60–7.73 (m, 18H), 7.28 (d, J¼8.1 Hz, 2H), 6.67 (s, 1H), 4.46
(t, J¼6.6 Hz, 4H), 4.16 (t, J¼6.9 Hz, 4H), 2.12–2.09 (m, 4H), 1.98–1.94
(m, 4H), 1.14–1.60 (m, 88H), 0.78–0.88 (m, 12H). 13C NMR (CDCl3):
(0.34 g, 82%). 1H NMR (CDCl3):
d
9.00 (d, J¼1.8 Hz, 1H), 8.80–8.92 (m,
6H), 8.76 (d, J¼4.8 Hz, 2H), 8.20–8.24 (m, 8H), 7.79–7.75 (m, 9H), 7.34
(d, J¼5.7 Hz,1H), 4.60–4.56 (m, 2H), 4.10–4.06 (m, 2H), 3.89–3.85 (m,
2H), 3.82–3.79 (m, 2H), 3.75–3.71 (m, 2H), 3.64–3.61 (m, 2H), 3.42 (s,
d
163.0, 156.5, 150.4, 150.3, 150.2, 150.1, 150.0, 146.1, 143.0, 142.9,
135.9,134.6,134.5,134.4,134.3, 132.0,131.8,127.4, 127.3, 126.5,126.3,
121.7, 121.1, 121.0, 120.9, 120.0, 111.0, 70.1, 69.8, 32.0, 31.9, 29.7, 29.6,
29.5, 29.4, 29.3, 29.2, 26.1, 26.0, 22.7, 22.6,14.1,14.0. MS (MALDI-TOF):
m/z 2367.2 [MþH]þ. Anal. Calcd for C152H172Zn2N10O6$3H2O: C,
75.44; H, 7.41; N, 5.79. Found: C, 75.40; H, 7.31; N, 5.58.
3H), ꢁ2.78 (s, 2H). 13C NMR (CDCl3):
d 165.7, 157.2, 147.2, 142.1, 139.9,
138.5, 136.6, 134.6, 131.4, 129.0, 127.8, 126.7, 120.5, 120.4, 117.6, 117.1,
111.8, 72.0, 70.9, 70.7, 69.5, 68.8, 59.1. MS (MALDI-TOF): m/z 821.1
[MþH]þ. Anal. Calcd for C52H44N4O6: C, 76.08; H, 5.40; N, 6.82.
Found: C, 75.46; H, 5.49; N, 6.34.
4.1.6. Compound Cu21. A mixture of H41 (46 mg, 0.021 mmol) and
copper acetate dihydrate (100 mg, 0.45 mmol) in dichloromethane
(15 mL) and methanol (5 mL) was stirred at rt for 20 h. The solvent
was removed under reduced pressure and the resulting residue was
dissolved in chloroform (50 mL). The solution was then washed with
water (40 mLꢀ3) and brine (40 mL) and dried over sodium sulfate.
The solvent was removed again and the resulting residue purified by
column chromatography (petroleum ether/CH2Cl2 1:1) to give Cu21
as red solid (40 mg, 91%). IR (KBr): 3389, 2924, 2853,1658,1537,1490,
1468, 1004, 796 cmꢁ1. UV–vis (decalin): 415, 538 nm. MS (MALDI-
TOF): m/z 2362.3, 2240.4. Anal. Calcd for C152H172Cu2N10O6: C, 77.29;
H, 7.34; N, 5.93. Found: C, 77.22; H, 6.67; N, 5.82.
4.1.10. Compound 21. A mixture of tetraethyleneglycolmono methyl
ether (2.08 g, 10 mmol) and sodium hydride (1.00 g, 60%) in dry THF
(25 mL) was stirred at room temperature for 12 h and then heated
under reflux for 0.5 h to afford the solution of 20. The suspensionwas
cooled to room temperature, and then under stirring 1924 (1.00 g,
2.20 mmol) was added slowly. Stirring was continued for 6 h, the
solvent was then removed under vacuum and diluted hydrochloric
acid (0.01 N,100 mL) added. The suspensionwas extracted with ethyl
acetate (100 mLꢀ3). The combined organic phase was washed with
water (100 mLꢀ2), brine (100 mL) and dried over sodium sulfate.
After removal of the solvent with a rotavapor, the resulting residue
was purified by column chromatography (AcOEt/MeOH 20:1) to give
4.1.7. Compound 16. A suspension of 1422 (3.00 g, 16.7 mmol), 1523
(5.30 g, 16.7 mmol) and potassium carbonate (6.00 g, 43.5 mmol) in
DMF (75 mL) were stirred at 90 ꢂC for 17 h, cooled to rt and then
filtrated. The filtrate was concentrated and diluted with dichloro-
methane (400 mL). The organic phase was washed with H2O
(200 mLꢀ3) and brine (200 mL) and dried over sodium sulfate.
After removal of the solvent, the resulting residue was subjected to
flash chromatography (CH2Cl2) to give 16 as oil (5.01 g, 92%). 1H
21 as yellow oily liquid (0.81 g, 26%). 1H NMR (CDCl3):
d 8.69 (s, 1H),
6.86 (s, 1H), 4.34 (t, J¼4.5 Hz, 4H), 3.93 (t, J¼4.5 Hz, 4H), 3.73
(t, J¼3.0 Hz, 4H), 3.59–3.65 (m, 16H), 3.52–3.48 (m, 4H), 3.34 (s, 6H).
13C NMR (CDCl3):
d 157.8,131.4,125.4,100.7, 72.6, 71.9, 71.1, 70.6, 70.5,
69.2, 61.7, 59.0. MS (ESI): m/z 603.2 [MþNa]þ. Anal. Calcd for
C24H40N2O14: C, 49.65; H, 6.94; N, 4.83. Found: C, 49.50; H, 7.35;
N, 4.43.
NMR (CDCl3):
d
9.82 (s, 1H), 8.26 (d, J¼2.1 Hz, 1H), 7.95 (d, J¼2.4 Hz,
4.1.11. Compound 22. A mixture of 21 (0.16 g, 0.28 mmol) and Pd–C
(10%, 0.10 g) in THF (20 mL) and methanol (20 mL) was stirred in
a flask, connected with a hydrogen balloon, at rt for 22 h. The solid
was filtrated and filtrate concentrated under vacuum to give 21 as
crude product. The compound was unstable and dissolved in DMF
(10 mL) for the next reaction without further purification.
1H), 7.06 (s, 1H), 4.25 (t, J¼4.8 Hz, 2H), 3.88 (t, J¼4.8 Hz, 2H), 3.84 (s,
3H), 3.72 (t, J¼2.7 Hz, 2H), 3.58–3.63 (m, 4H), 3.49 (t, J¼2.7 Hz, 2H),
3.30 (s, 3H). 13C NMR (CDCl3):
d 190.0, 165.5, 134.4, 134.3, 129.2,
120.9, 113.5, 71.9, 71.1, 70.7, 70.5, 69.3, 69.2, 59.0, 52.2. MS (ESI): m/z
327.1 [MþH]þ. HRMS (MALDI-TOF): Calcd for C16H22O7Na [MþNa]:
349.1258. Found: 349.1248.
4.1.12. Compound H42. A solution of 18 (0.42 g, 0.51 mmol) and
HATU (800 mg, 2.10 mmol) were in dry DMF (30 mL) was stirred for
1 h. Then, a solution of the above sample of 22 in DMF (10 mL) was
4.1.8. Compound 17. To a stirred solution of 8 (6.36 g, 60.0 mmol)
and 16 (4.51 g, 13.8 mmol) in propanoic acid (300 mL) was added 9

10190
Z.-Y. Xiao et al. / Tetrahedron 65 (2009) 10182–10191
added dropwise. The mixture was stirred for another 24 h, con-
centrated under vacuum and diluted with dichloromethane
(100 mL). The organic phase was washed with water (50 mLꢀ3)
and brine (50 mL) and dried over sodium sulfate. After removal of
the solvent, the resulting residue was purified by column chro-
matography (CH2Cl2/methanol 20:1) to give H42 as purple solid
afford 4 as a dark brown solid (103 mg, 43%). 1H NMR (CDCl3):
(4H), 3.85 (4H), 3.79–3.76 (m, 4H), 3.64–3.60 (m, 16H), 3.54–3.50
(m, 4H), 3.35 (s, 6H). 13C NMR (CDCl3):
163.5, 146.5, 146.0, 145.3,
145.2, 144.9, 144.7, 144.6, 144.4, 144.0, 143.9, 143.5, 143.4, 143.0,
142.4,142.2,141.9,141.7,140.9,139.1, 71.9, 71.4, 70.6, 70.5, 68.8, 66.2,
59.0. MS (MALDI-TOF): m/z 1225.6 [MþNa]þ. HRMS (MALDI-TOF):
Calcd for C81H38O12Na [MþNa]þ: 1225.2255. Found: 1225.2245.
d 4.62
d
(0.10 g, 19%, two steps). 1H NMR (CDCl3):
d 10.27 (s, 2H), 9.32 (s, 1H),
9.10 (d, J¼2.4 Hz, 2H), 8.75–8.85 (m, 16H), 8.16–8.21 (m, 14H), 7.59–
7.76 (m, 18H), 7.35 (d, J¼8.4 Hz, 2H), 6.81 (s, 1H), 4.68 (t, J¼4.8 Hz,
4H), 4.34 (t, J¼4.8 Hz, 4H), 4.13 (t, J¼4.8 Hz, 4H), 3.92 (t, J¼4.8 Hz,
4H), 3.78 (t, J¼4.8 Hz, 4H), 3.35–3.65 (m, 36H), 3.32 (s, 6H), 3.26 (s,
4.1.17. Compound 29. To
a
stirred solution of 2726 (0.16 g,
0.50 mmol), 28 (0.11 g, 0.25 mmol) and DMAP (25 mg) in dichloro-
methane (30 mL) was added EDCI (0.25 g, 1.30 mmol). The mixture
was stirred at rt for 12 h and then washed with water (20 mLꢀ4),
brine (20 mL) and dried over sodium sulfate. After removal of the
solvent vacuum, the resulting residue was purified by column chro-
matography (petroleum ether/EtOAc 20:1) to give 29 as a colorless
6H), ꢁ2.83 (s, 4H). 13C NMR (CDCl3):
d 163.0, 156.6, 146.4, 142.1,
138.0, 134.6, 130.8, 129.1, 127.6, 126.7, 122.6, 121.5, 120.1, 118.9, 111.9,
71.8, 70.9, 71.8, 70.9, 70.8, 70.7, 70.5, 70.4, 69.8, 69.6, 69.5, 59.1, 59.0.
MS (MALDI-TOF): m/z 2127.1 [MþH]þ. HRMS (MALDI-TOF): Calcd
for C128H129N10O20: 2125.9379. Found: 2125.9365.
solid (92 mg, 49%). IR (KBr):
873 cmꢁ1.1H NMR (CDCl3):
4.64 (s, 2H), 4.15 (t, J¼6.9 Hz, 2H), 3.49 (s, 2H), 2.34 (d, J¼7.8 Hz, 2H),
0.84–2.05 (m, 69H), 0.68 (s, 3H).13C NMR(CDCl3):
166.6,166.1,166.0,
n
2920, 2851,1749,1468,1203,1140,1062,
d
5.38 (d, J¼3.6 Hz,1H), 4.70–4.66 (m,1H),
4.1.13. Compound Zn22. A mixture of H42 (30 mg, 0.014 mmol) and
zinc acetate dihydrate (100 mg, 0.45 mmol) in dichloromethane
(30 mL) and methanol (10 mL) was stirred at rt for 20 h, concentrated
and diluted with chloroform (10 mL). The organic solution was
washed with water (5 mLꢀ3) and brine (5 mL) and dried over sodium
sulfate. The solvent was removed again and the residue was purified
by column chromatography (CH2Cl2/MeOH 20:1) to give Zn22 as
d
139.2,123.0, 75.5, 65.9, 61.6, 56.7, 56.2, 50.0, 42.3, 41.1, 39.5, 36.6, 36.2,
35.8, 31.9, 31.8, 29.7, 29.6, 29.5, 29.4, 29.2, 28.5, 25.8, 22.8, 22.7, 19.3,
18.7,14.1. Anal. Calcd for C48H82O6: C, 76.34; H,10.94. Found: C, 76.24;
H, 11.16.
a purple solid (28 mg, 89%). 1H NMR (CDCl3):
d
9.94 (s, 2H), 9.13 (s,
4.1.18. Compound 5. To a stirred solution of fullerene (0.14 g,
0.20 mmol), CBr4 (66 mg, 0.20 mmol) and 29 (150 mg, 0.20 mmol)
in toluene (150 mL) was added DBU (68 mL, 0.20 mmol). The solu-
tion was stirred at rt for 4 h and then concentrated. The resulting
residue was purified by column chromatography (first CS2 to
remove unreacted C60, then toluene) to afford 5 as a dark brown
1H), 8.80–8.95 (m, 18H), 8.16–8.22 (m, 14H), 7.65–7.76 (m, 18H), 7.35
(d, J¼8.4 Hz, 2H), 6.66 (s, 1H), 4.52 (t, J¼4.2 Hz, 4H), 4.15 (t, J¼4.5 Hz,
4H), 3.98 (t, J¼4.5 Hz, 4H), 3.71 (t, J¼4.5 Hz, 4H), 3.62 (t, J¼4.5 Hz, 4H),
3.33–3.43 (m, 12H), 3.13–3.17 (m, 6H), 3.04 (t, J¼4.2 Hz, 4H), 2.91–
2.97 (m, 6H), 2.79 (t, J¼1.8 Hz, 4H), 2.70 (t, J¼4.2 Hz, 4H), 2.65 (s, 6H),
2.54 (s, 6H). 13C NMR (CDCl3):
d
163.3, 156.2, 150.1, 146.9, 143.1, 137.6,
solid (92 mg, 31%). IR (KBr):
1096, 801, 526 cmꢁ1 1H NMR (CDCl3):
4.77–5.73 (m, 1H), 4.54 (t, J¼6.0 Hz, 2H), 2.38 (d, J¼7.8 Hz, 2H),
0.84–2.05 (m, 69H), 0.68 (s, 3H). 13C NMR (CDCl3):
165.8, 163.2,
n
2920, 2850, 1747, 1464, 1262, 1197,
137.5, 136.4, 134.5, 132.0, 131.8, 128.5, 127.3, 126.4, 122.1, 121.4, 120.9,
119.5, 118.4, 111.6, 100.5, 71.8, 71.1, 70.8, 70.4, 70.1, 69.9, 69.8, 69.6,
69.4, 69.3, 58.9, 58.3, 58.2. HRMS (MALDI-TOF): Calcd for
C128H124N10O20Zn [M]þ: 2248.7571. Found: 2248.7548.
.
d
5.39 (s, 1H), 4.95 (s, 2H),
d
163.1, 145.4, 145.3, 145.2, 145.1, 144.9, 144.7, 144.6, 143.9, 143.0,
142.9, 142.2, 141.9, 141.0, 139.4, 139.2, 138.8, 123.2, 77.3, 77.0, 76.8,
75.8, 71.4, 67.7, 62.8, 56.7, 56.2, 50.0, 42.3, 39.5, 36.2, 35.8, 31.9, 31.8,
29.8, 29.7, 29.4, 29.3, 28.2, 28.0, 23.8, 22.8, 22.7, 22.6, 19.4, 18.7, 14.1,
11.9. HRMS (MALDI-TOF): Calcd for C108H80O6Na: 1495.5847.
Found: 1495.5868 [MþNa]þ.
4.1.14. Compound 3. A solution of DBU (34 mL, 0.10 mmol), fullerene
(72 mg, 0.10 mmol), iodine (66 mg, 0.20 mmol) and 2325 (55 mg,
0.10 mmol) in toluene (50 mL) was stirred at rt for 4 h and then
concentrated under vacuum. The resulting residue was purified by
column chromatography (first with CS2 to remove unreacted fuller-
ene and then with toluene) to afford 3 as a dark brown solid (47 mg,
4.1.19. Compound 31. To
a
stirred solution of 3027 (0.82 g,
37%). 1H NMR (CDCl3):
d
4.49 (t, J¼6.3 Hz, 4H), 1.84 (t, J¼7.2 Hz, 4H),
3.70 mmol), cholesterol (3.00 g, 7.70 mmol), DMAP (0.30 g) and HOBt
(0.10 g) in dichloromethane (100 mL) was added EDCI (3.50 g,
18.0 mmol). The mixture was stirred at rt for 72 h, then washed with
water (100 mLꢀ3) and brine (100 mL) and dried over sodium sulfate.
After removal of the solvent under vacuum, the resulting residue was
purified by column chromatography (CH2Cl2) to give 31 as a white
1.18–1.48 (m, 52H), 0.88 (t, J¼6.0 Hz, 6H). 13C NMR (CDCl3):
d 163.7,
145.4, 145.3, 145.2, 144.9, 144.7, 144.6, 143.9, 143.1, 143.0, 142.2, 142.0,
141.0,139.0, 71.8, 67.5, 31.9, 31.4, 30.2, 29.7, 29.6, 29.4, 29.3, 28.6, 26.0,
22.7, 14.1. MS (MALDI-TOF): m/z 1271 [MþH]þ. HRMS (MALDI-TOF):
Calcd for C95H67O4 [MþH]þ: 1271.5082. Found: 1271.5034.
solid (1.53 g, 43%). IR (KBr):
1070 cmꢁ1. 1H NMR (CDCl3):
2H), 4.65 (s, 4H), 3.62 (s, 2H), 2.39 (d, J¼7.8 Hz, 4H), 0.84–2.05 (m,
76H), 0.68 (s, 6H). 13C NMR (CDCl3):
166.5, 165.4, 139.2, 123.1, 75.6,
n
2938, 2868,1782,1755,1468,1224,1140,
4.1.15. Compound 26. A solution of 24 (0.26 g, 2.5 mmol), 25 (1.04 g,
5.0 mmol) and p-toluenesulfonic acid (35 mg) in benzene (60 ml)
was heated at reflux azeotropically for 6 h and then concentrated.
The resulting residue was purified by column chromatography
(CH2Cl2/EtOH 40:1) to give 26 as colorless liquid (1.17 g, 97%). 1H
d
5.39 (d, J¼3.6 Hz, 2H), 4.72–4.69 (m,
d
61.7, 56.7, 56.1, 50.0, 42.3, 39.7, 39.5, 37.9, 36.9, 36.6, 36.2, 35.8, 31.9,
31.8, 28.2, 28.0, 27.6, 24.3, 23.8, 22.8, 22.6, 21.0, 19.3, 18.7, 11.9. Anal.
Calcd for C61H96O8: C, 76.52; H, 10.11. Found: C, 76.21; H, 9.78.
NMR (CDCl3):
d
4.30 (t, J¼4.8 Hz, 4H), 3.71 (t, J¼4.8 Hz, 4H), 3.63–
3.66 (m, 20H), 3.55 (t, J¼5.4 Hz, 4H), 3.45 (s, 2H), 3.38 (s, 6H). 13C
NMR (CDCl3):
d
166.4, 71.9, 70.6, 70.5, 68.8, 64.5, 59.0, 41.2. MS (ESI):
4.1.20. Compound 6. To a stirred solution of C60 (0.14 g, 0.20 mmol),
CBr4 (66 mg, 0.20 mmol) and 31 (0.19 g, 0.20 mmol) in toluene
(150 mL) was added DBU (100 mL, 0.30 mmol). The solution was
stirred at rt for 4 h and then concentrated under vacuum. The
resulting residue was purified by column chromatography (first
using CS2 to remove unreacted C60, then toluene) to afford 6 as
m/z 485.2 [MþH]þ. HRMS (MALDI-TOF): Calcd for C21H40O12Na
[MþNa]þ: 507.2417. Found: 507.2411.
4.1.16. Compound 4. To a stirred solution of fullerene (144 mg,
0.20 mmol), iodine (50 mg, 0.20 mmol) and 26 (100 mg, 0.10 mmol)
in toluene (80 mL) was added DBU (80
m
L, 0.24 mmol). The solution
a dark brown solid (77 mg, 23%). IR (KBr):
1262, 1197, 1096, 1025, 803, 527 cmꢁ1. 1H NMR (CDCl3):
J¼2.7 Hz, 2H), 4.97 (s, 4H), 4.78–4.75 (m, 2H), 2.37 (d, J¼9.6 Hz, 4H),
0.85–2.03 (m, 76H), 0.67 (s, 6H). 13C NMR (CDCl3):
165.9, 162.7,
n
2961, 2866, 1747, 1465,
was stirred for 20 h and then concentrated under vacuum. The
resulting residue was purified by column chromatography (first
toluene to remove unreacted fullerene, then toluene/EtOH 20:1) to
d
5.39 (d,
d

Z.-Y. Xiao et al. / Tetrahedron 65 (2009) 10182–10191
10191
Tetrahedron Lett. 2007, 48, 7327–7331; (c) Li, Z.-T.; Hou, J.-L.; Li, C. Acc. Chem. Res.
2008, 41, 1343–1353.
145.2, 144.7, 143.9, 143.0, 142.2, 141.9, 141.0, 139.3, 123.2, 76.6, 75.8,
56.7, 56.1, 50.0, 42.3, 39.7, 39.5, 38.0, 36.6, 36.2, 35.8, 31.9, 31.8, 29.7,
28.2, 28.0, 27.7, 24.3, 23.8, 22.8, 22.6, 21.0, 19.4, 18.7, 11.9. MS
(MALDI-TOF): m/z 1698 [MþNa]þ.
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Acknowledgements
We are grateful to NSFC (Nos. 20732007, 20621062, 20672137,
and 20872167), NBRP (2007CB808001) and STCSM (09XD1405300)
for financial support.
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