Synthesis of a bis-macrotricyclic host and its complexation with secondary ammonium salts: An acid-base switchable molecular handcuff

Article abstract of DOI:10.1002/ejoc.201000675

A novel triptycene-derived bis-macrotricyclic host was designed and synthesized. The host was shown to form a 1:4 stable complex with 4 equiv. of dibenzylammonium salt in solution and in the solid state. Moreover, it was found that the host with multicavities could also self-assemble with2 equiv. of bis-secondary ammonium salt to form a handcufflike structure under the tested condition ([1]₀ = 3.0 mM). The complexation and decomplexation of the assembly could be further chemically controlled by the stimuli of acid and base.

Full text of DOI:10.1002/ejoc.201000675

FULL PAPER
DOI: 10.1002/ejoc.201000675
Synthesis of A Bis-Macrotricyclic Host and Its Complexation with Secondary
Ammonium Salts: An Acid–Base Switchable Molecular Handcuff
Jia-Bin Guo,[a,b] Jun-Feng Xiang,[a] and Chuan-Feng Chen*[a]
Keywords: Self-assembly / Structure elucidation / Host–guest systems / Macrocycles
A novel triptycene-derived bis-macrotricyclic host was de-
signed and synthesized. The host was shown to form a 1:4
stable complex with 4 equiv. of dibenzylammonium salt in
solution and in the solid state. Moreover, it was found that
the host with multicavities could also self-assemble with
2 equiv. of bis-secondary ammonium salt to form a handcuff-
like structure under the tested condition ([1]0 = 3.0 m ). The
complexation and decomplexation of the assembly could be
further chemically controlled by the stimuli of acid and base.
M
ity and two lateral circular cavities and demonstrated that
the host could exhibit interesting guest-dependent complex-
ation with different guests. Especially, it was found[10c] that
host 2 could form a 1:2 complex with 2 equiv. of secondary
ammonium salts, which could subsequently provide some
opportunities for developing specific supramolecular as-
semblies. Herein, we report the synthesis of novel trip-
tycene-derived bis-macrotricyclic host 1 (Figure 1), com-
plexation between 1 and dibenzylammonium salts in solu-
tion and in the solid state, formation of a handcuff-like mo-
lecular assembly, and switchable process of the molecular
handcuff by the stimuli of acid and base.
Introduction
Macrocyclic hosts have undoubtedly played key roles in
host–guest chemistry, and they have been also one of the
key sources for the development of new supramolecular sys-
tems with specific structures and properties.[1] Since Ped-
ersen first reported the synthesis and cation-complexing
characteristics of the crown ethers in 1967,[2] various macro-
cyclic hosts have been hitherto developed. Especially,
macrocyclic hosts with multiple cavities and multiple re-
cognition sites have attracted increasing interest because
they are not only fundamental in understanding the molec-
ular recognition and self-assembly processes pertinent to
the origin of life and evolution, but also helpful for de-
veloping specific supramolecular systems and designing
new classes of materials and devices for future technol-
ogies.[3] Recent successful examples in this regard included
the wide applications of the hosts in the construction of
molecular machines,[4] higher order interlocked structures,[5]
and other specific supramolecular assemblies.[6,7] However,
such macrocyclic hosts are limited, and the design and syn-
thesis of new classes of the hosts with multicavities are still
thrilling and challenging topics in host–guest chemistry.
In 1995, Stoddart and co-workers first reported that di-
benzo-24-crown-8 (DB24C8) could be threaded by a sec-
ondary ammonium ion to form a [2]pseudorotaxane,[8]
which resulted in the synthesis of various interlocked mole-
cules.[9] Recently, we[10] synthesized novel triptycene-based
macrotricyclic host 2 containing one central cylindrical cav-
[a] Beijing National Laboratory for Molecular Sciences, CAS Key
Laboratory of Molecular Recognition and Function, Institute
of Chemistry, Chinese Academy of Sciences,
Beijing 100190, China
Fax: +86-10-62554449
E-mail: cchen@iccas.ac.cn
[b] Graduate School, Chinese Academy of Sciences,
Beijing 100049, China
Figure 1. Structures and proton designations of hosts 1 and 2 and
guests 3 and 4.
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201000675.
View this journal online at
wileyonlinelibrary.com
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Synthesis of an Acid–Base Switchable Molecular Handcuff
Synthesis of guest 4 is outlined in Scheme 2. Ditosylation
of diol 8[12] and then reaction with 4-hydroxybenzaldehyde
gave 10. Condensation of 10 with benzylamine, reduction
with NaBH4, protonation of the resulting amine, and coun-
terion exchange with NH4PF6 formed target guest 4 in 88%
yield over the four steps.[13] All new compounds were con-
firmed by 1H and 13C NMR spectroscopy, mass spectrome-
try, and elemental analysis.
Results and Discussion
Synthesis of Triptycene-Derived Bis-Macrotricyclic Host 1
and Bis-Dibenzylammonium Salt 4
Synthesis of host 1 is depicted in Scheme 1. Cylindrical
macrotricyclic diester 6 was obtained in 66% yield by the
reaction of macrocyclic compound 5[11] and dimethyl ace-
tylenedicarboxylate. Hydrolysis of 6 in sodium hydroxide
solution followed by dehydrolysis in acetic anhydride gave
7 in 83% yield over two steps. Anhydride 7 was further
treated with p-phenylenediamine to afford 1 in 59% yield.
Complexation between 1 and Dibenzylammonium Salt 3 in
Solution and in the Solid State
First, we investigated the complexation between host 1
and dibenzylammonium salt 3 in solution. As shown in Fig-
1
ure 2, the H NMR spectrum of a 1:4 mixture of 1 and 3,
recorded in CDCl3/CD3CN (5:1) showed a dispersed array
of well-defined resonances and a major difference from
those of host 1 and guest 3. The resonances of the complex
1
were assigned by its H–1H COSY 2D NMR spectrum.[13]
The benzyl proton signals of 3 located outside the cavities
of 1 were shifted downfield, whereas those of the benzyl
protons inside the cavities were shifted upfield. In particu-
lar, striking upfield shifts (∆δ = –1.35 to –1.91 ppm) for the
inner phenyl proton (Hb~Hd) signals were observed, and
this may be attributed to the strong shielding effect of the
macrocycle. The signal of the outer benzylic methylene pro-
+
ton HaЈ adjacent to the NH2 center exhibited a large
downfield shift (∆δ = 0.55 ppm), which was attributed to
the hydrogen-bonding interactions and the deshielding ef-
fect of the aromatic rings in 1. Moreover, upfield shifts for
aromatic protons H3 (∆δ = –0.18 ppm) and H4 (∆δ =
–0.16 ppm) of 1 and significant changes in the chemical
shifts of the protons in the crown ether units were also ob-
served. These observations suggested that 1 and 3 combined
to form the 1:4 complex 1·34.
Scheme 1. Synthesis of host 1.
Figure 2. Partial 1H NMR spectra (300 MHz; CDCl3/CD3CN, 5:1)
of (a) free host 1, (b) free guest 3, and (c) 1 and 4.0 equiv. of 3.
[1]0 = 3.0 m.
As shown in Figure 3, when guest 3 was gradually added
1
into the solution of host 1, it was found that the H NMR
spectra showed two sets of signals for the protons H3 (5.64
Scheme 2. Synthesis of guest 4.
and 5.41 ppm) and H4 (5.67 and 5.47 ppm) of host 1, indi-
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J.-B. Guo, J.-F. Xiang, C.-F. Chen
FULL PAPER
cating a slow exchange complexation between host 1 and and two dibenzylammonium ions are threaded through the
guest 3. The electrospray ionization mass spectrum (ESI- center of the DB24C8 cavities of each macrotricycles in host
MS) provided more evidence for the formation of complex 1, which results in 1:4 complex 1·34. Interestingly, it was
1·34. Consequently, peaks at m/z = 1116.4, 1001.9, and found that two central cavities formed in host 1 are along
– 4+
801.3 for [1·34-3PF6–]3+, [1·33-3PF6–]3+, and [1·34-4PF6 ]
,
the same axis, whereas the dihedral angle/centroid–centroid
distance between the aromatic rings A and B of the guest
situated outside of the cavities are all 9.68°/23.13 Å. There
are multiple hydrogen-bonding interactions between the
polyether oxygen atoms and the NH2+ hydrogen atoms and
the benzylic methylene hydrogen atoms located both inside
and outside the cavities. Also, C–H···π interactions are evi-
dent between host 1 and the guests with distances of 2.86
(p), 2.81 (s), and 2.73 Å (t), respectively. Moreover, an offset
face–face π···π stacking interaction between the inner
phenyl ring of the guest and one of the aromatic rings of
the host with the dihedral angle/centroid–centroid distance
of 3.53°/3.29 Å (q) was also observed. These multiple non-
covalent interactions might play an important role in the
formation of stable complex 1·34, which is also consistent
with the result observed in solution.
respectively, were observed.[13]
Formation of a Handcuff-Like Molecular Assembly
Figure 3. Partial 1H NMR spectra (300 MHz; CDCl3/CD3CN, 5:1)
of host 1 upon the addition of 3: (a) 0, (b) 0.6, (c) 1.2, (d) 1.8, (e)
2.4, (f) 3.0, (g) 3.6, (h) 4.0, (i) 4.2, (j) 4.8, (k) 5.4, (l) 6.0, (m) 6.6,
and (n) 7.2 equiv. [1]0 = 3.0 m.
The formation of complex 1·34 encouraged us to further
design and construct a handcuff-like assembly. The first evi-
dence for the formation of the handcuff-like assembly in
1
solution came from its H NMR spectrum. As shown in
Further support for the formation of complex 1·34 came
from its X-ray crystal structure.[14] As shown in Figure 4,
host 1 contains two symmetrical macrotricyclic moieties,
Figure 5, when a solution of 1 in CDCl3/CD3CN (5:1) was
mixed with 2 equiv. of 4, only one set of peaks was found
(Figure 5c). With the aid of 2D NMR (1H–1H COSY) ex-
periments, almost all the resonances could be assigned to
an assembly of 1·42. Similar to those of complex 1·34, the
host–guest exchange is also slow on the 1H NMR timescale
at different temperatures (Figure S19, Supporting Infor-
mation) and significant upfield shifts for the inner phenyl
protons and downfield shifts for the benzylic methylene
protons HaЈ were observed. Moreover, large chemical shifts
for the signals of protons H3, H4, and the protons of the
crown rings of host 1 were also observed. However, it was
Figure 4. Top view (a) and side view (b) of the crystal structure of
–
complex 1·34. Solvent molecules, PF6 counterions, and hydrogen
atoms not involved in the interactions are omitted for clarity. Hy-
drogen bond lengths [Å]: a = 2.55, c = 2.44, d = 2.44, e = 2.23, h
= 2.00, i = 2.52, j = 2.52, k = 2.09 for N–H···O; b = 2.89 for N–
H···C; f = 2.33, g = 2.52, l = 2.33, m = 2.63, n = 2.47, o = 2.15, r
= 2.63 for C–H···O; p = 2.86, s = 2.81, t = 2.73 for C–H···π; q =
3.29 for π···π stacking interaction.
Figure 5. Partial 1H NMR spectra (300 MHz; CDCl3/CD3CN, 5:1)
of (a) free host 1, (b) free guest 4, and (c) 1 and 2.0 equiv. of 4.
[1]0 = 3.0 m.
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Synthesis of an Acid–Base Switchable Molecular Handcuff
noted that the signals of protons H3 and H4 split into three 3 formed a stable complex 1·34, but when 6 equiv. of tribu-
set of peaks, which may be attributed to the asymmetry of tylamine (TBA) was added into the solution of 1·34 in
the phenyl rings inside the cavities and the asymmetry of CDCl3/CD3CN (5:1), it was found that the proton signals
two macrotricyclic moieties arising from the linking of each of complex 1·34 totally disappeared, whereas the signals for
of the two ammonium salts on the two sides. Particularly, protons Hb, Hc, and Hd shifted downfield and the signals
it was different from complex 1·34 in which the proton H5 of protons HaЈ, HbЈ, HcЈ, and HdЈ shifted upfield. Moreover,
of host 1 showed a relatively obvious upfield shift (∆δ = the aromatic proton and crown ether proton signals of host
–0.06 ppm), which might be due to the shielding effect of 1 shifted almost to the original positions. These observa-
the aromatic rings in 4. These observations suggested that tions indicated that the disassociation of complex 1·34 had
a new handcuff-like assembly was formed.
occurred. When 12 equiv. of trifluoroacetic acid (TFA) was
To further ascertain the formation of the molecular added to the above solution, the characteristic proton sig-
handcuff at the tested concentration, a diffusion-ordered nals of complex 1·34 reappeared, which indicated the com-
NMR (Figure 6) experiment of the 1:2 mixture of 1 ([10] plex was formed again.
= 3.0 m) and 4 in a CDCl3/CD3CN (5:1) solution was
performed. The result showed that only one species with
the hydrodynamic radius[15] (or Stokes radius) of 20.45 Å
was observed in the solution, which agreed well with the
measurement obtained from the crystal structure of 1·34
with a length of 21.70 Å at its longest points. This result
led us to conclude that the single species in solution should
be the handcuff-like assembly. The ESI-MS results provided
more evidence for the formation of the 1:2 complex between
1 and 4. As a result, the peaks at m/z = 1413.37, 1024.1,
– +
and 987.6 for [1·42-3PF6–]3+, [1·42-4PF6–]4+, and [4-PF6 ] ,
respectively, were observed (Figure S21, Supporting Infor-
mation).
Figure 7. Partial 1H NMR spectra (300 MHz; CDCl3/CD3CN, 5:1)
of (a) complex 1.34, (b) complex 34 upon the addition of 6 equiv.
of TBA, and (c) complex 34 in the presence of TBA (6 equiv.) upon
the addition of 12 equiv. of TFA.
Because the association and disassociation of complex
1·34 could be controlled by pH, we reasoned that the “mo-
lecular handcuff” assembly could also be switched “on” or
“off” by the addition of acid and base. As shown in Fig-
Figure 6. DOSY NMR spectrum (600 MHz; CDCl3/CD3CN, 5:1;
298 K) of 1 and 2.0 equiv. of 4. [1]0 = 3.0 m (plotted using the log
values of the diffusion constant).
Switchable Process of the Molecular Handcuff by the
Stimuli of Acid and Base
Inspired by the fact that the association and disassocia-
tion of the complex between DB24C8 and the secondary
ammonium ion can be chemically controlled by pH, we de-
duced that the complexation process between host 1 and
Figure 8. Partial 1H NMR spectra (300 MHz; CDCl3/CD3CN, 5:1)
guests 3 and 4 could also be switched by acid and base. We
of (a) complex 1·42, (b) complex 1·42 upon the addition of 6 equiv.
first studied the complexation process between host 1 and
of TBA, and (c) complex 1·42 in the presence of TBA (6 equiv.)
guest 3. As shown in Figure 7, host 1 and 4 equiv. of guest upon the addition of 12 equiv. of TFA.
Eur. J. Org. Chem. 2010, 5056–5062
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J.-B. Guo, J.-F. Xiang, C.-F. Chen
FULL PAPER
ArH), 4.06–3.67 (m, 56 H, OCH2CH2O, OCH3), 2.24 (s, 6 H,
CCH3), 2.10 (s, 6 H, CCH3) ppm. 13C NMR (75 MHz, CDCl3,
25 °C): δ = 166.0, 150.7, 148.8, 145.9, 145.8, 142.3, 141.6, 124.5,
119.9, 109.5, 109.3, 71.0, 69.9, 51.8, 49.1, 47.8, 13.7 ppm. MS
(MALDI-TOF): m/z = 1237.4 [M + Na]+, 1253.4 [M + K]+.
C68H78O20·3H2O (1268.54): calcd. C 64.34, H 6.67; found C 64.56,
H 6.91.
ure 8, when 6 equiv. of TBA was added to the solution, the
characteristic signals of assembly 1·42 disappeared and the
proton signals of host 1 shifted to relevant positions charac-
teristic of the free species (Figure 8b). The resonances of
1
these free species were assigned by using H–1H COSY 2D
NMR spectroscopy.[13] The subsequent addition of
12 equiv. of TFA could further regenerate assembly 1·42.
Consequently, the switchable process of the molecular
handcuff could be achieved by the stimuli of acid and base
(Figure 9).
Compound 7: Hydrolysis of 6 (0.44 g, 0.36 mmol) in methanol/10%
NaOH (5:7, 96 mL) at 80 °C for 8 h. The mixture was cooled to
ambient temperature, acidified with 10% hydrochloric acid, and
extracted with dichloromethane (3ϫ30 mL). The combined extract
was dried with anhydrous sodium sulfate and concentrated. The
residue was dissolved in acetic anhydride (20 mL) and stirred under
reflux for 6 h. The crude product obtained after evaporation of
the organic solvent was recrystallized from dichloromethane and
isopropyl ether to obtain anhydride 7 (0.35 g, 83%) as a yellow
solid. M.p. 212–214 °C. 1H NMR (300 MHz, CDCl3, 25 °C): δ =
7.25 (d, J = 4.9 Hz, 2 H, ArH), 6.98 (dd, J = 5.4, 3.1 Hz, 2 H,
ArH), 6.86 (s, 4 H, ArH), 6.83 (s, 4 H, ArH), 4.10–3.68 (m, 48
H, OCH2CH2O), 2.24 (s, 12 H, CCH3) ppm. 13C NMR (75 MHz,
CDCl3, 25 °C): δ = 161.1, 160.0, 148.8, 146.1, 145.7, 142.3, 140.5,
124.6, 119.9, 109.8, 109.0, 71.1, 71.0, 70.0, 69.9, 69.9, 69.8, 48.8,
47.8, 13.7, 11.7 ppm. MS (MALDI-TOF): m/z = 1191.3 [M +
Na]+, 1207.2 [M + K]+. C66H72O19·H2O (1186.48): calcd. C 66.77,
H 6.28; found C 66.75, H 6.10.
Figure 9. Schematic representation of the acid–base switchable mo-
lecular handcuff.
Host 1: To a stirred solution of p-phenylenediamine (13 mg,
0.12 mmol) in anhydrous DMF (2.5 mL) was added anhydride 7
(0.35 g, 0.3 mmol) at room temperature under an argon atmo-
sphere. The mixture was stirred at 25 °C for 1 h and to this was
added acetic anhydride (3.5 mL), pyridine (1.75 mL), and DMF
(1.25 mL). After stirring for 1 h, the mixture was heated at 90 °C
for 10 h. A solid precipitated after the reaction mixture was cooled.
The product was collected as a pale-yellow solid (170 mg, 59%)
after filtration and washing with methanol. M.p. Ͼ300 °C. 1H
NMR (300 MHz, CDCl3, 25 °C): δ = 7.25 (d, J = 5.2 Hz, 4 H, 2-
H), 7.21 (s, 4 H, 5-H), 6.97 (dd, J = 5.4, 3.1 Hz, 4 H, 1-H), 6.87
(s, 8 H, 4-H), 6.83 (s, 8 H, 3-H), 4.13–3.65 (m, 96 H, OCH2CH2O),
2.27 (s, 12 H, CCH3), 2.24 (s, 12 H, CCH3) ppm. 13C NMR
(75 MHz, CDCl3, 25 °C): δ = 165.1, 157.5, 148.8, 145.9, 145.7,
142.3, 141.5, 130.7, 126.5, 124.6, 119.9, 109.7, 109.1, 71.1, 70.0,
69.9, 69.8, 48.6, 47.8, 13.7, 12.1 ppm. MS (MALDI-TOF): m/z =
2431.3 [M + Na]+. C138H148N2O36·2H2O (2445.00): calcd. C 67.74,
H 6.26, N 1.14; found C 67.84, H 6.12, N 1.27.
Conclusions
In summary, we have synthesized a novel triptycene-de-
rived bis-macrotricyclic host and also demonstrated that it
could form a 1:4 stable complex with 4 equiv. of dibenz-
ylammonium salt in solution and in the solid state. More-
over, we have shown that a handcuff-like assembly could be
formed by complexation between the host and 2 equiv. of
bis-secondary ammonium ions, and the molecular handcuff
could further be switched by the stimuli of acid and base.
Our future work will focus on exploring the applications
of the host in constructing other specific supramolecular
assemblies such as molecular ladders[16] and molecular
locks.[17]
Experimental Section
Compound 9: A solution of 8[17] (1.10 g, 2.45 mmol), TsCl (1.12 g,
5.88 mmol), Et3N (0.74 g, 7.35 mmol), and DMAP (30.5 mg,
0.25 mmol) in anhydrous dichloromethane (80 mL) was stirred un-
der reflux for 12 h. After cooling to room temperature, the reaction
mixture was neutralized with 10% hydrochloric acid and then
washed with water (3ϫ60 mL) after the addition of dichlorometh-
ane (70 mL). The combined organic phase was concentrated and
purified by column chromatography (ethyl acetate/petroleum, 5:1)
General Information: Melting points were measured with an elec-
trothermal melting point apparatus. NMR spectra were recorded
with a Bruker AV 300 NMR or Bruker AV 600. MALDI-TOF
mass spectra were obtained with a Bruker BIFLEX III mass spec-
trometer with CCA. ESI mass spectra were obtained with a FT-
ICR MS spectrometer. Elemental analyses were carried out with
an Elemental FLASH EA1112 instrument. Materials obtained
commercially were used without further purification.
1
to give 9 (1.36 g, 74%) as a white solid. M.p. 56–58 °C. H NMR
Compound 6: A solution of macrotricycle 5[11] (0.59 g, 0.55 mmol)
and dimethyl acetylenedicarboxylate (0.3 g, 2.12 mmol) in diethyl-
ene glycol dimethyl ether (6 mL) was stirred at 110 °C for 22 h un-
der an argon atmosphere. The crude product obtained after evapo-
ration of the organic solvent was dissolved in methanol (5 mL) and
heated under reflux for 30 min. After cooling to room temperature,
the mixture was filtered, and the solid was recrystallized from
dichloromethane and methanol to afford 6 (0.44 g, 66%) as a pale-
yellow solid. M.p. 262–264 °C. 1H NMR (300 MHz, CDCl3,
25 °C): δ = 7.26 (s, 2 H, ArH), 6.97 (s, 2 H, ArH), 6.82 (s, 8 H,
(300 MHz, CDCl3, 25 °C): δ = 7.78 (d, J = 6.7 Hz, 4 H, ArH), 7.45
(d, J = 7.0 Hz, 4 H, biphenyl ArH), 7.31 (d, J = 7.0 Hz, 4 H, ArH),
6.95 (d, J = 7.0 Hz, 4 H, biphenyl ArH), 4.15 (d, J = 2.2 Hz, 8 H,
OCH2CH2O), 3.83 (s, 4 H, OCH2CH2O), 3.67 (m, 8 H, OCH2-
CH2O), 3.62 (s, 4 H, OCH2CH2O), 2.41 (s, 6 H, ArCH3) ppm. 13C
NMR (75 MHz, CDCl3, 25 °C): δ = 157.9, 144.8, 133.6, 133.1,
129.8, 128.0, 127.7, 114.9, 70.8, 69.8, 69.3, 68.7, 67.5, 21.6 ppm.
MS (MALDI-TOF): m/z = 781.6 [M + Na]+, 797.5 [M + K]+.
C38H46O12S2 (758.24): calcd. C 60.14, H 6.11; found C 60.16, H
6.13.
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Synthesis of an Acid–Base Switchable Molecular Handcuff
Compound 10: A mixture of compound 9 (1.36 g, 1.79 mmol), p-
hydroxybenzaldehyde (0.44 g, 3.58 mmol), and K2CO3 (1.48 g,
10.8 mmol) in anhydrous CH3CN (50 mL) was heated at reflux un-
der an argon atmosphere for 16 h. After cooling to room tempera-
ture, the reaction mixture was filtered and the solid was washed
with CH3CN (30 mL). The combined organic filtrate was concen-
trated, and crude compound 10 was then dissolved in dichloro-
methane (80 mL), washed with dilute HCl, and dried with MgSO4.
Solvents were removed under reduced pressure, and the crude prod-
uct was purified by column chromatography (CH2Cl2/ethyl acetate,
10:1) to afford 10 (1.18 g, 100%) as a white solid. M.p. 94–96 °C.
1H NMR (300 MHz, CDCl3, 25 °C): δ = 9.86 (s, 2 H, CHO), 7.80
(d, J = 8.8 Hz, 4 H, ArH), 7.44 (d, J = 8.8 Hz, 4 H, ArH), 7.00 (d,
J = 8.7 Hz, 4 H, ArH), 6.95 (d, J = 8.7 Hz, 4 H, ArH), 4.24–4.11
(m, 8 H, OCH2CH2O), 3.89 (m, 8 H, OCH2CH2O), 3.76 (s, 8 H,
OCH2CH2O) ppm. 13C NMR (75 MHz, CDCl3, 25 °C): δ = 190.7,
163.9, 157.9, 133.6, 131.9, 130.1, 127.6, 114.9, 114.9, 71.0, 70.9,
69.9, 69.5, 67.8, 67.6 ppm. MS (MALDI-TOF): m/z = 658.6 [M]+,
681.6 [M + Na]+, 697.5 [M + K]+. C38H42O10 (658.28): calcd. C
69.29, H 6.43; found C 69.16, H 6.34.
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[2]
[3]
[4]
[5]
[6]
Compound 4: A solution of 10 (1.18 g, 1.8 mmol) and benzylamine
(0.385 g, 3.6 mmol) in toluene (60 mL) was stirred at reflux in a
Dean–Stark apparatus for 12 h. After cooling the mixture to room
temperature, the solvent was removed in vacuo, and the residue was
added to a solution of NaBH4 (1.36 g, 36 mmol) in THF (40 mL).
Methanol (20 mL) was added in small portions to the reaction mix-
ture, which was heated at reflux with stirring for 8 h. It was then
allowed to cool and dilute HCl was added (pH Ͻ 2). After evapora-
tion of the solvent, the residue was suspended in H2O (60 mL) and
extracted with dichloromethane (4ϫ50 mL). The combined extract
was washed with 5% aqueous NaHCO3 (2ϫ50 mL) and H2O
(50 mL) and then dried with MgSO4. Removal of the solvent under
vacuum afforded a pale solid, which was dissolved in methanol
(50 mL). Concentrated HCl was added (pH Ͻ 2), and the reaction
mixture was stirred for 5 h. Evaporation of the solvent afforded a
pale solid, which was suspended in acetone (40 mL). An aqueous
solution of NH4PF6 was added until dissolution occurred. Evapo-
ration of acetone afforded compound 4 as a white solid, which was
isolated, washed with H2O, and dried in vacuo (1.8 g, 88%). M.p.
98–100 °C. 1H NMR (300 MHz, [D6]acetone, 25 °C): δ = 8.43 (s, 4
H, NH2), 7.86–7.22 (m, 18 H, ArH), 7.01 (dd, J = 8.7, 6.4 Hz, 8
H, ArH), 4.57 (d, J = 8.8 Hz, 8 H, OCH2CH2O), 4.30–4.08 (m, 8
H, OCH2CH2O), 3.84 (m, 8 H, OCH2CH2O), 3.70 (s, 8 H, OCH2-
CH2O) ppm. 13C NMR (75 MHz, [D6]acetone, 25 °C): δ = 161.0,
159.1, 134.1, 132.7, 132.0, 131.0, 130.5, 130.0, 128.3, 123.8, 115.9,
115.8, 71.5, 70.4, 70.3, 68.6, 68.5, 52.4, 52.3 ppm. MS (MALDI-
TOF): m/z = 841.6 [M – H – 2PF6]+. C52H62F12N2O8P2 (1132.38):
calcd. C 55.12, H 5.52, N 2.47; found C 55.37, H 5.50, N 2.37.
[7]
[8]
[9]
CCDC-744055 (for 1·34) contains the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
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Supporting Information (see footnote on the first page of this arti-
1
1
cle): H NMR and 13C NMR spectra of new compounds; H–1H
1
1
COSY, H NMR titration and variable-temperature H NMR ex-
periments; mass spectra (ESI) of complexes 1·34 and 1·42.
Acknowledgments
We thank the National Natural Science Foundation of China
(20625206, 20772126), Chinese Academy of Sciences, and National
Basic Research Program (2007CB808004) for financial support.
Eur. J. Org. Chem. 2010, 5056–5062
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
5061

J.-B. Guo, J.-F. Xiang, C.-F. Chen
FULL PAPER
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[15] The hydrodynamic radius refers to a hypothetical hard sphere
that diffuses at the same rate as the molecule; it does not give
the exact size of nonspherical species.
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[14] Crystal data for 1·34·2CH2ClCH2Cl: C99H110Cl2F12N3O18P2,
Mw = 1990.74, crystal size 0.18ϫ0.16ϫ0.14 mm3, monoclinic,
space group P21/c, a = 16.397(6) Å, b = 27.887(10) Å, c = [17] a) K.-I. Yamashita, M. Kawano, M. Fujita, J. Am. Chem. Soc.
30.957(11) Å, β = 98.431(4)°, V = 14003(8) Å3, Z = 4, Dcalcd.
=
2007, 129, 1850–1851; b) W. S. Jeon, E. Kim, Y. H. Ko, I. H.
Hwang, J. W. Lee, S. Y. Kim, H. J. Kim, K. Kim, Angew. Chem.
Int. Ed. 2005, 44, 87–91.
0.944 Mgm–3, T = 113(2) K, µ = 0.133 mm–1, 83153 reflections
measured, 24645 unique (Rint = 0.0716), final R indices
[IϾ2σ(I)]: R1 = 0.1221, wR2 = 0.3123, R indices (all data): R1
= 0.1676, wR2 = 0.3489.
Received: May 11, 2010
Published Online: July 23, 2010
5062
www.eurjoc.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2010, 5056–5062