Synthesis of bis(m-phenylene)-32-crown-10-based discrete rhomboids driven by metal-coordination and complexation with paraquat

Article abstract of DOI:10.1021/jo900461g

(Figure Presented) Two bis(m-phenylene)-32-crown-10 derivatives containing two pyridyl or carboxyl groups were made. They were used to prepare three bis(m-phenylene)-32-crown-10-based discrete rhomboids by coordination-driven self-assembly with high yield

Full text of DOI:10.1021/jo900461g

Synthesis of Bis(m-phenylene)-32-crown-10-Based Discrete
Rhomboids Driven by Metal-Coordination and Complexation
with Paraquat
†
‡
†
†
†
†
Kelong Zhu, Jiuming He, Shijun Li, Ming Liu, Feng Wang, Mingming Zhang,
‡
§
†
,†
Zeper Abliz, Hai-bo Yang, Ning Li, and Feihe Huang*
Department of Chemistry, Zhejiang UniVersity, Hangzhou 310027, China, Institute of Materia Medica,
Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China, and
Department of Chemistry, East China Normal UniVersity, Shanghai 200062, China
fhuang@zju.edu.cn
ReceiVed March 1, 2009
Two bis(m-phenylene)-32-crown-10 derivatives containing two pyridyl or carboxyl groups were made.
They were used to prepare three bis(m-phenylene)-32-crown-10-based discrete rhomboids by coordination-
driven self-assembly with high yields. The formation of these crown ether-based rhomboids was confirmed
by NMR, UV-vis, CSI-TOF-MS, and elemental analysis. The complexation of these crown ether-based
assemblies with paraquat (N,N′-dimethyl-4,4′-bipyridinium) was studied. The complexation of neutral
bis(crown ether) rhomboid 1 with paraquat was found to be statistical with a 1:2 stoichiometry. The
average apparent association constant Kav of the complexation of rhomboid 1 with paraquat was found
3
-1
to be about 8.8((0.8) × 10 M in acetone, about 17 times higher than the reported association constant
value for the complexation of the corresponding simple bis(m-phenylene)-32-crown-10 with paraquat.
This is possibly because the carboxylate groups provide additional noncovalent interactions between the
host and guest. No obvious complexation was observed between the cationic rhomboids and paraquat
when studied by NMR, UV-vis, and CSI-TOF-MS analysis. This could be attributed to the combination
of the charge repulsion between cationic pyridinium rings and cationic platinum atoms and the weak
π-π stacking and charge transfer interactions between the phenyl rings and the pyridinium rings caused
by the electron-withdrawing effect of the cationic platinum atoms.
Introduction
mediated self-assembly has been proven to be a highly efficient
strategy for the construction of discrete two-dimensional (2-D)
and three-dimensional (3-D) architectures with predetermined
Supramolecular self-assemblies have attracted great interest
due to their potential applications in sensing devices, catalysis,
and host-guest materials. Coordination-driven transition-metal-
1
2
4
shapes, sizes, andgeometries. These metal-organic assemblies,
3
(
1) (a) Purakayastha, A.; Baruah, J. B. New J. Chem. 1999, 23, 1141–1142.
*
To whom correspondence should be addressed. Fax: 86 571 8795 1895.
(b) Keefe, M. H.; Benkstein, K. D.; Hupp, J. T. Coord. Chem. ReV. 2000, 205,
201–228. (c) Resendiz, M. J. E.; Noveron, J. C.; Disteldorf, H.; Fischer, S.;
Stang, P. J. Org. Lett. 2004, 6, 651–653. (d) Guo, Y.; Shao, S.; Xu, J.; Shi, Y.;
Jiang, S. Tetrahedron Lett. 2004, 45, 6477–6480. (e) Yamashita, K.; Kawano,
M.; Fujita, M. Chem. Commun. 2007, 4102–4103.
Phone: 86 571 8795 3189.
†
Zhejiang University.
Chinese Academy of Medical Sciences and Peking Union Medical College.
East China Normal University.
‡
§
1
0.1021/jo900461g CCC: $40.75  2009 American Chemical Society
J. Org. Chem. 2009, 74, 3905–3912 3905
Published on Web 04/21/2009

Zhu et al.
1
4
possessing unique magnetic, photophysical, and/or redox prop-
erties which are not accessible from purely organic systems,
have shown promise as a new class of functional receptor
molecular machines, and supramolecular polymers. Previous
work has illustrated that crown ethers can also be used as flexible
11
building blocks to construct discrete complexes. More recently,
Stang et al. reported several discrete cavity-cored self-assemblies
containing multiple pendant dibenzo-24-crown-8 (DB24C8)
1
c,5
meolecules.
By incorporating functionalities, such as por-
6
7
8
9
10
phyrin, carborane, calixarene, cavitand, ferrocene, and
5
d,e,11
5d,e
crown ether,
into the final discrete assemblies, artificial
derivatives.
These DB24C8-containing hosts have a similar
functional nanoscale devices with precisely controlled shapes,
ability to bind dibenzylammonium guest(s) as does DB24C8
in nonpolar solvents, such as dichloromethane.
1
2
5d,e
sizes, and geometries can be constructed.
Crown ethers have attracted much attention for their interest-
1
3
ing binding properties with metal and organic cations. They
have been widely used in the preparation of chemosensors,
(
2) (a) Fujita, M.; Kwon, Y. J.; Washizu, S.; Ogura, K. J. Am. Chem. Soc.
1
5
994, 116, 1151–1152. (b) Kang, J.; Rebek, J., Jr. Nature (London) 1997, 385,
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The significant recognition motif based on bis(m-phenylene)-
-crown-10 (BMP32C10) (4) and paraquat (N,N′-dimethyl-4,4′-
(
3
bipyridinium) (5) derivatives has been employed to prepare
6
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15a-f
numerous host-guest complexes
and a fluorescence
44, 1125–1131. (e) Tashiro, S.; Tominaga, M.; Yamaguchi, Y.; Kato, K.; Fujita,
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5g
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chromophore.
We envisioned that the combination of the
BMP32C10-based bispyridyl or dicarboxyl donor units and
appropriately designed Pt(II) acceptors can afford novel func-
tionalized molecular devices with precisely controlled shapes,
sizes, and geometries via the coordination-driven self-assembly
process. The resulting multicrown ether-based self-assemblies,
varying in location and total number of incorporated crown ether
moieties, may exhibit different affinities for guest(s) compared
with that of the single bis(m-phenylene)-32-crown-10 host. For
example, it is possible to use metal-coordination to control the
binding of the BMP32C10 units to paraquat if the bispyridyl
or dicarboxyl donor units are conjugated or very close to the
crown ether moieties. Herein, we report the synthesis of three
1
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BMP32C10-based discrete supramolecular rhomboids by
metal-coordination-driven self-assembly of the 60° Pt(II)-based
building blocks and functionalized dicarboxyl or bispyridyl
bridging ligands, and the study of the complexation of these
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A. Synthesis of Crown Ether-Based 120° Donor Precur-
sors 9 and 11. The key starting material 7 was prepared
according to the literature. The intermediate BMP32C10-based
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3
906 J. Org. Chem. Vol. 74, No. 10, 2009

Bis(m-phenylene)-32-crown-10-Based Discrete Rhomboids
a
SCHEME 1. Synthesis of Crown Ether-Based 120° Donor Precursor 9
a
2 2 3
Reagents and conditions: (a) (i) NaH, DMF, 50 °C, (ii) tetra(ethylene glycol) dichloride, N , K CO , DMF, 110 °C, 24 h, 65% (two steps); (b) dimethyl
4
,6-dihydroxyisophthalate, K
2 3
CO , TBAB, NaI, N
2 2
, DMF, 110 °C, 5 days, 35%; (c) (i) NaOH, EtOH, 12 h, (ii) HCl, H O, 95% (two steps).
a
SCHEME 2. Synthesis of Crown Ether-Based 120° Donor Precursor 11
a
Reagents and conditions: (a) 4,6-dibromoresorcinol, K
NH, reflux, 24 h, 83%.
2 3 2 3 2 2
CO , TBAB, NaI, N , DMF, 110 °C, 5 days, 45%; (b) 4-ethynylpyridine hydrochloride, Pd(Ph P) Cl ,
CuI, i-Pr
2
a
SCHEME 3. Synthesis of Pt(II)-Containing 60° Corner
a
3 4 2 3 2 2
Reagents and conditions: (a) Pt(PEt ) , N , toluene, 40 °C, 24 h, 50%; (b) AgNO , CH Cl , 90%.
reasonable yields by a pseudohigh dilution method for preparing
the disodium salt. Adding this disodium salt solution to an
acetone solution containing 1.0 equiv of the 60° corner 6 resulted
in a near-colorless solution. The rhomboid 1 could be precipi-
tated as a white solid in 95% isolated yield by slow evaporation
of acetone upon stirring in the open air or adding water.
1
7
4
reported by Gibson et al. As outlined in Scheme 1,
cyclization of 7 with dimethyl 4,6-dihydroxyisophthalate in the
presence of TBAB and NaI afforded the dicarbomethoxy
intermediate 8 in 35% isolated yield followed by the hydrolysis
of 8 with NaOH in EtOH and recrystallization from acetone to
give the pure BMP32C10-based macrocyclic 120° donor precur-
sor 9 almost quantitatively (95%). The dibromo intermediate
The cationic rhomboid 2 was assembled in CH
2 2
Cl from the
Pt(II)-containing 60° corner 6 and the 120° bispyridyl building
1
0b
block 11.
By stirring at room temperature for 12 h, a
1
0 was prepared by cyclization of 7 with 4,6-dibromoresorcinol
homogeneous yellow solution was formed. The nitrate salt 2
can be precipitated by adding pentane to the resulting yellow
solution. It also can be purified by a vapor diffusion method
often employed to obtain single crystals. Since 2 has a poor
solubility in acetone, which is a good solvent for complexation
by the same method in 45% isolated yield. The bispyridyl 120°
donor precursor 11 was finally obtained from 10 and 4-ethy-
nylpyridine via the Sonogashira coupling reaction in 83%
isolated yield (Scheme 2).
B. Synthesis of Pt(II)-Containing 60° Corner 6. The Pt(II)-
containing 60° corner was prepared from 2,9-dibromophenan-
6
study, the nitrate salt was exchanged with KPF in deionized
water to afford the hexafluorophosphate salt 3.
1
6a
31
threne (12) in two steps according to the literature.
The
The P NMR spectrum of 1 (Figure 1b) indicates the
formation of a single, highly symmetric structure by the sharp
singlet at 17.78 ppm with concomitant 1 Pt satellites. It shifted
approximately 2.38 ppm upfield relative to its position in
precursor 6, which is similar to that of the rhomboid prepared
intermediate 13 was obtained by a double oxidative addition of
tetrakis(triethylphosphine)platinum(0). Exchanging the bromine
atoms to more liable nitrates by reaction with AgNO afforded
3
the pure Pt(II)-containing 60° corner 6 (Scheme 3).
95
1
6b
C. Self-Assembly and Spectral Studies of BMP32C10-
Based Supramolecular Rhomboids 1, 2, and 3. The neutral
supramolecular rhomboid 1 was assembled according to a
from isophthalate and 6. The small change in the position of
the phosphorus signal could be attributed to the similar Pt-O
2
coordinate bond (Pt-OOC- vs. Pt-ONO ) in the starting Pt(II)-
containing 60° corner. The chemical environments of the
16a
method reported by Stang et al. The 120° dicarboxy building
block 9 was dissolved in an aqueous NaHCO solution to afford
3
phosphorus atoms in the cavity are only slightly changed even
J. Org. Chem. Vol. 74, No. 10, 2009 3907

Zhu et al.
FIGURE 1. Partial 31P NMR spectra (202.3 MHz, CDCl
SCHEME 4. Synthesis of BMP32C10-Based Neutral Supramolecular Rhomboid 1
3
, 22 °C) of 4.00 mM 6 (a), 2.00 mM 1 (b), and 2.00 mM 2 (c).
when the electron-rich crown ethers are incorporated. The 31P
NMR spectrum of 2 (Figure 1c) also gave a sharp singlet but
more upfield chemical shift at 12.86 ppm with accompanying
the slight upfield shifts of H
, H
, H
, and H10 after 6 was
2
7
9
incorporated into the rhomboid 1 could be also attributed to
the similar Pt-O coordinate bond (Pt-OOC- vs. Pt-ONO
in the starting Pt(II)-containing 60° corner. The proton H on
2
)
195
Pt satellites. The relatively bigger upfield shift is possibly
a
due to the fact that the pyridine nitrogen atom in rhomboid 2 is
a better electron donor than the carboxylate oxygen atom in
rhomboid 1. This spectral evidence suggests both 1 and 2 are
the isophthalate moiety exhibited a relatively large upfield shift,
about 0.75 ppm, after the Pt-O coordinate bond was formed.
The metal-coordination could also affect the ethyleneoxy protons
on the crown ether deeply by changing the electron density of
1
single macrocyclic species. Furthermore, the H NMR spectra
(
2
spectrum b in Figure 2 and spectrum b in Figure 3) of 1 and
also confirmed the highly symmetric structure and display
significant spectroscopic differences from the precursor building
blocks. The small downfield shifts of H , H , H , and H and
the crown ether. The overlapped signal position for HR′ and H
ꢀ
was obviously split into two separated peaks. All the protons
on the phenanthrene exhibited downfield shifts when the Pt-N
coordination was formed in the rhomboid 2 (Figure 3). Also
1
4
5
8
3
908 J. Org. Chem. Vol. 74, No. 10, 2009

Bis(m-phenylene)-32-crown-10-Based Discrete Rhomboids
1
FIGURE 2. Partial H NMR spectra (400 MHz, 22 °C) of 4.00 mM 6 (a), 2.00 mM 1 (b), and 4.00 mM 9 (c) in CDCl
3
.
1
FIGURE 3. Partial H NMR spectra (400 MHz, 22 °C) of 4.00 mM 6 (a), 2.00 mM 2 (b), and 4.00 mM 11 (c) in CDCl
3
.
the Pt-N coordination had the same influence on all of the
protons on the crown ether-based bispyridyl ligand which all
moved downfield. The singlet peak of the R-pyridine protons
confirmed that the dicarboxy 9 was incorporated into the self-
assembly 1 and the bispyridine 11 was incorporated into the
self-assembly 2 (Schemes 4 and 5).
f
H was split into two doublets, indicating the different environ-
Further evidence for the formation of the desired self-
assembly was obtained by cold spray ionization mass spec-
ments for the inner and outer pyridine protons caused by the
confined rotation of the Pt-N bond (spectra b and c in Figure
18
trometry (CSI-MS). For the self-assembly 1, peaks were
1
3
). This is a characteristic feature of the H NMR spectrum of
+
observed corresponding to [M + H] (m/z 3323.00) and [M +
1
6d
such a discrete rhomboid.
+
Na] (m/z 3344.96). These were all isotopically resolved and
The UV-vis spectra show there is no band shift, but an
increase in intensity was observed for self-assembly 1 after the
crown ether was incorporated (Figure S38, see the Supporting
Information). In the fluorescence spectra, the strong emission
intensity of bispyridyl ligand 11 at 389 nm, excited at 353 nm,
was quenched after the Pt-N coordination was formed and
shifted to a weak emission band at 422 nm (Figure S40, see
the Supporting Information). All of this spectroscopic evidence
are in excellent agreement with their theoretical distributions
(
Figure S26a, see the Supporting Information). As for the self-
assembly 2, peaks were found attributable to the consecutive
loss of counterions in excellent agreement with their theoretical
2+
3+
distributions: [M - 2NO
3
+
]
(m/z 1839.68), [M - 3NO
(m/z 888.86) (Figure S26b, see the
Supporting Information). The isotopically resolved peaks at m/z
3
]
(m/z
4
1
3
205.72), [M - 4NO ]
1
922.77, 1233.45, and 888.81 agree very well with the theoreti-
2+
3+
cal distribution of the species, [M - 2PF
and [M - 4PF ] , corresponding to consecutive loss of
6
6 6
] , [M - 3PF ] ,
(
17) Gibson, H. W.; Nagvekar, D. S.; Yamaguchi, N.; Wang, F.; Bryant,
W. S. J. Org. Chem. 1997, 62, 4798–4803.
18) CSI-TOF-MS is a sort of electrospray ionization (ESI) MS operated
4+
(
counterions of self-assembly 3 (Figure S27, see the Supporting
Information). Also a peak at m/z 1294.77 was found and
under low temperature: (a) Sakamoto, S.; Fujita, M.; Kim, K.; Yamaguchi, K.
Tetrahedron 2000, 56, 955–964. (b) Yamanoi, Y.; Sakamoto, Y.; Kusukawa,
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3+
attributed to the [M - 2PF + K] species.
6
9
81. (c) Sakamoto, S.; Yoshizawa, M.; Kusukawa, T.; Fujita, M.; Yamaguchi,
K. Org. Lett. 2001, 3, 1601–1604. (d) Yamaguchi, K. J. Mass Spectrom. 2003,
8, 473–490.
D. The Study of the Complexation of Rhomboid 1 with
3
Paraquat 5. The X-ray structural analysis of the complex
J. Org. Chem. Vol. 74, No. 10, 2009 3909

Zhu et al.
SCHEME 5. Synthesis of BMP32C10-Based Cationic Supramolecular Rhomboid 2 and 3
between 1 and 5 was unsuccessful due to the instability of the
and c in Figure 6) were opposite to the chemical shift changes
of these protons when 6 and 9 were assemblied into the
rhomboid 1 (Figure 2) and gave evidence about the change of
the electron density of the phenanthrene moieties after com-
orange crystals obtained by vapor diffusion of pentane into a
1
9
mixed solution of 1 (2.00 mM) and 5 (4.00 mM) in acetone.
The complexation of 1 with paraquat 5 was characterized by
31
UV-vis, proton NMR, P NMR, and CSI-TOF-MS. When a
plexation. The significant chemical shift change of protons H
, H , H , and H on 1 (spectra a, b, and c in Figure 6) indicated
the π-π stacking between the phenyl rings of 1 and the
pyridinium rings of 5. The signals of H , H , HR′, and Hꢀ′ of 1
moved upfield, while those of H moved downfield after
a
,
2
.00 mM acetone solution of 1 and a 4.00 mM solution of 5
H
b
c
d
e
were mixed, a yellow color resulted. The absorption spectrum
of the mixture shows a new band (Figure 4) that can be
attributed to the charge transfer between electron-rich aromatic
rings of the host and electron-poor pyridinium rings of the guest.
R
ꢀ
γ
complexation between 1 and 5 (spectra a, b, and c in Figure 6).
These are similar to what happened on the corresponding protons
on 4 after complexation between 4 and 5 (spectra c, d, and e in
Figure 6), indicating that the host-guest interaction between
the crown ether moieties of 1 and paraquat guest 5 is similar to
that between the corresponding simple crown ether 4 and
2
0
A Job plot (Figure 5) based on UV-vis absorbance data of
the charge transfer band (λ ) 403 nm) demonstrated that the
1
complex was of 1:2 stoichiometry in solution. The H NMR
spectrum of a mixed solution of 1 (2.00 mM) and 5 (4.00 mM)
in acetone-d
Figure 6), the same as the reported complexation between 4
and 5. The upfield shifts of H , H , H , and H and the downfield
shifts of H , H , H , and H10 after complexation (spectra a, b,
6
showed the complexation is a fast exchange system
31
1
(
paraquat guest 5. The P{ H} NMR spectra of a mixed solution
of 1 (2.00 mM) and 5 (4.00 mM) in acetone-d (Figure S33,
see the Supporting Information) exhibited a slight change (∆δ
0.4 ppm) indicating that the binding of the bipyridium cation
1
4
5
8
6
2
7
9
)
can change the chemical environment of the phosphorus atoms.
FIGURE 5. Job plot showing the 1:2 stoichiometry of the complex
FIGURE 4. UV-vis spectra of 2.00 mM 1 (red), 2.00 mM 1 and 4.00
mM 5 (yellow), and 4.00 mM 5 (blue) in acetone.
between 1 and 5. [1]
0
+ [5]
0
0 0
) 6.00 mM. [1] and [5] are the initial
concentrations of 1 and 5.
3
910 J. Org. Chem. Vol. 74, No. 10, 2009

Bis(m-phenylene)-32-crown-10-Based Discrete Rhomboids
1
FIGURE 6. Partial 400 MHz H NMR spectra of 2.00 mM 1 (a), 2.00 mM 1 and 4.00 mM 5 (b), 4.00 mM 5 (c), 4.00 mM 4 and 4.00 mM 5 (d),
6
and 4.00 mM 4 (e) in acetone-d .
The CSI-MS spectra (Figure S36, see the Supporting Informa-
between the host and guest. The sensitivity of the neutral
tion) of the mixture of 1 and 5 in acetone further confirmed the
rhomboid 1 to paraquat makes it a possible chemosensor for
paraquat.
3+
15g
1
:2 stoichiometry by the fragments: [1 + 5 + 5 - 3PF
6
]
(m/z
4+
1
279.68) and [1 + 5 + 5 - 4PF
The yellow color of the acetone-d
and 5 (4.00 mM) was deeper than that of the equimolar acetone-
6
]
(m/z 923.73).
E. The Study of the Complexation of Rhomboids 2 and
1
solution of 1 (2.00 mM)
3 with Paraquat 5. The UV-vis spectra and the H NMR
6
spectra of a mixed solution of 3 (2.00 mM) and 5 (4.00 mM)
d
6
solution of 4 and 5 at 4.00 mM, indicating the stronger π-π
6
in acetone-d gave no evidence for the complexation between
stacking and charge transfer interactions between the host and
3 and 5. The UV-vis spectra displayed little change after the
guest for 1 and 5 than for 4 and 5. The average association
cationic self-assembly 3 was mixed with 5 (Figure S39, see the
1
constant (Kav) of 1·5
2
was determined by probing the charge
Supporting Information). All the protons on 3 in the H NMR
transfer band of the complex by UV-vis spectroscopy and
spectrum of the mixed solution of 3 (2.00 mM) and 5 (4.00
2
1
employing a titration method. Progressive addition of an
6
mM) in acetone-d were observed to have almost the same
1
acetone solution with high guest 5 concentration and low host
chemical shift as the H NMR spectrum of 3 (spectra a and b
in Figure S31, see the Supporting Information). The negligible
change of the chemical shift of the proton H5b on 5 (spectra b
and c in Figure S31, see the Supporting Information) may be
attributed to the side-on interactions between the electron-rich
1
concentration to an acetone solution with the same host 5
concentration results in an increase of the intensity of the charge
transfer band of the complex. Treatment of the collected
2
2
absorbance data at λ ) 403 nm by a Scatchard plot afforded
the corresponding Kav value. The linear nature of this plot
demonstrated that the complexation between host 1 and guest
1
5f
phenyl rings of 3 and electron-poor pyridinium rings of 5.
The 31P{ H} NMR spectrum of a mixed solution of 3 (2.00
1
5
is statistical (Figure S42b, see the Supporting Information).
mM) and 5 (4.00 mM) in acetone-d does not show any
6
From the slope and the intercept of the Scatchard plot, the Kav
detectable change compared with that of 3 (Figure S34, see the
Supporting Information), also indicating no complexation
between 3 and 5. Though a 1:1 complex with a very weak
intensity could be found in the CSI-MS spectra of a mixture of
2 and 5 (Figure S37, see the Supporting Information), no
complexation could be found in that of a mixture of 3 and 5.
The poor affinity of rhomboid 2 or 3 for paraquat may result
from two things. First, the repulsion between the cationic 2 or
3 and the cationic bipyridinium cation can severely weaken the
complexation between the crown ether portion and the bipyri-
dinium cation. Second, since the pyridine units are conjugated
with the phenylene rings of the BMP32C10 moieties in
rhomboid 2 or 3, the electron-withdrawing cationic platinum
can reduce the electron density of the phenyl rings of the crown
ether moieties and then weaken the π-π stacking and charge
transfer interactions between them and the pyridinium rings.
Though no complexation was observed between rhomboid 2
or 3 and the bipyridinium cation, the cationic assembly may be
3
-1
value was determined to be 8.8((0.8) × 10 M for 1·5
2
. As
a 1:2 stoichiometry, statistical complexation system, the K
1
,
[
1
1·5]/{[1][5]}, and K
2
, [1·5
.4((0.1) × 10 and 3.5((0.3) × 10 M , respectively (see
is about
7 times higher than the reported association constant value,
2
]/{[1·5][5]}, were calculated to be
4
3
-1
the Supporting Information). The value of Kav for 1·5
1
4
2
-1
15g
87 M , for the complexation beween 4 and 5. This result
shows that the affinity of the BMP32C10 portion for paraquat
was enhanced after the crown ether moiety was incorporated
into the neutral self-assembly 1. This is possibly because the
carboxylate groups provide additional noncovalent interactions
(
19) The orange crystals obtained by the vapor diffusion method are readily
to lose the lattice solvents under ambient condition even at low temperature.
was unsuccessful.
Therefore, the X-ray structural analysis of the complex 1·5
2
(
20) Job, P. Ann. Chim. 1928, 9, 113–203.
21) (a) Connors, K. A. Binding Constants; Wiley: New York, 1987. (b)
(
Corbin, P. S. Ph.D. Dissertation, University of Illinois at Urbana-Champaign,
Urbana, IL, 1999. (c) Ashton, P. R.; Ballardini, R.; Balzani, V.; Belohradsky,
M.; Gandolfi, M. T.; Philp, D.; Prodi, L.; Raymo, F. M.; Reddington, M. V.;
Spencer, N.; Stoddart, J. F.; Venturi, M.; Williams, D. J. J. Am. Chem. Soc.
2
3
a suitable host for metal, neutral, or anionic guests.
1
996, 118, 4931–4951. (d) Zhang, J.; Huang, F.; Li, N.; Wang, H.; Gibson,
H. W.; Gantzel, P.; Rheingold, A. L. J. Org. Chem. 2007, 72, 8935–8938.
22) Marshall, A. G. Biophysical Chemistry; J. Wiley and Sons: New York,
(23) (a) Whiteford, J. A.; Lu, C. V.; Stang, P. J. J. Am. Chem. Soc. 1997,
119, 2524–2533. (b) Lee, S. B.; Hwang, S. G.; Chung, D. S.; Yun, H.; Hong,
J.-I. Tetrahedron Lett. 1998, 39, 873–876. (c) M u¨ ller, C.; Whiteford, J. A.; Stang,
P. J. J. Am. Chem. Soc. 1998, 120, 9827–9837. (d) Whiteford, J. A.; Stang, P. J.
Inorg. Chem. 1998, 37, 5595–5601.
(
1
978; pp 70-77. Freifelder, D. M. Physical Biochemistry; W. H. Freeman and
Co.: New York, 1982; pp 659-660. Connors, K. A. Binding Constants; J. Wiley
and Sons: New York, 1987; pp 78-86.
J. Org. Chem. Vol. 74, No. 10, 2009 3911

Zhu et al.
Conclusion
in CH
mmol) in CH
2
Cl
2
(1.00 mL) and added to a solution of 6 (9.26 mg, 0.010
2
2
Cl (1.00 mL) dropwise. The mixture was stirred in
In summary, two donor units incorporated with BMP32C10
were designed and synthesized. By employing these new units,
three bis(m-phenylene)-32-crown-10-based discrete rhomboids
were synthesized via coordination-driven self-assembly and
characterized by NMR, UV-vis, and CSI-TOF-MS. The
complexation of these assemblies with paraquat was studied.
The neutral bis(crown ether) rhomboid 1 exhibited an enhanced
affinity for paraquat compared with simple bis(m-phenylene)-
the dark at room temperature for 24 h, resulting in a yellow solution.
By adding pentane, the nitrate salt 2 was precipitated as a pale
yellow solid. The solid was washed by toluene then pentane and
dried in vacuo. Yellow crystals were obtained by the diffusion of
1
acetone into a CH
2
Cl
2
solution. Yield 14.0 mg (91%); H NMR
(
(
8
3
400 MHz, CDCl , 22 °C) δ (ppm) 9.48 (d, 4H, J ) 6.0 Hz), 9.02
s, 4H), 8.74 (d, 4H, J ) 6.0 Hz), 7.80 (s, 2H), 7.73-7.76 (m,
H), 7.56 (m, 12H), 7.11 (t, 2H, J ) 8.0 Hz), 6.67 (s, 2H), 6.54 (s,
H), 6.48 (m, 4H), 4.30 (t, 8H, J ) 4.4 Hz), 4.10 (t, 8H, J ) 4.4
2
32-crown-10 while no complexation was observed between the
Hz), 4.01 (t, 8H, J ) 4.4 Hz), 3.82-3.86 (m, 16H), 3.70-3.81 (m,
cationic rhomboid 2 or 3 and paraquat 5. Therefore, it was
demonstrated that metal-coordination could be used to control
the binding of the BMP32C10 units to paraquat because the
bispyridyl or dicarboxyl donor units are conjugated or very close
to the crown ether moieties in the three rhomboids reported here.
Moreover, the convenient preparation and simple isolation and
purification of these rhomboids make it possible to prepare
functionalized self-assemblies on large scales as molecular
devices and our current efforts are focusing on developing
chemical sensors and large molecular machines based on these
self-assemblies.
31
1
2
4H), 1.37 (m, 48H), 1.11 (m, 72H); P { H} NMR (202.3 MHz,
CDCl , 22 °C) δ (ppm) 12.9 (s, JPt-P ) 2746 Hz); CSI-TOF-MS
m/z 1839.68 [M - 2NO
3
2
+
3+
3
] , 1205.72 [M - 3NO
3
] , and 888.86
4
+
[M - 4NO ] . Anal. Calcd for C N O P Pt : C, 50.07; H,
5.75; N, 3.07. Found: C, 49.92; H, 5.79; N, 3.09.
3
160 228
H
8
32
8
4
4,6-Bis(4-pyridylethynyl)-m-phenylene-m′-phenylene-32-crown-
0-Based Rhomboid (3). A solution of 2 (190 mg, 0.0500 mmol)
1
in deionized water (1.00 mL) was stirred at room temperature. A
saturated KPF aqueous solution (5.00 mL) was added dropwise
6
and a pale nearly white solid precipitated. The solid was centrifuged
and washed with deionized water (3 × 1.0 mL) and dried in vacuo.
1
Yield 20.0 mg (99%); H NMR (500 MHz, CD
(
4
3
COCD
3
, 22 °C) δ
ppm) 9.09 (d, 4H, J ) 5.0 Hz), 9.03 (d, 4H, J ) 5.0 Hz), 8.74 (s,
Experimental Section
H), 7.91 (d, 4H, J ) 5.5 Hz), 7.87 (s, 2H), 7.85 (d, 4H, J ) 5.5
Hz), 7.77 (d, 4H, J ) 7.5 Hz), 7.69 (d, 4H, J ) 7.5 Hz), 7.66 (s,
4
,6-Dicarboxyl-m-phenylene-m′-phenylene-32-crown-10-Based
Rhomboid (1). The dicarboxy precursor 9 was neutralized with an
equivalent amount of NaHCO at ambient temperature, assisted by
4
8
1
(
1
H), 7.13 (t, 2H, J ) 8.5 Hz), 7.00 (s, 2H), 6.48 (m, 6H), 4.43 (t,
H, J ) 4.5), 4.08 (t, 8H, J ) 4.5), 4.00 (t, 8H, J ) 4.5), 3.80 (m,
3
13
6H), 3.63-3.70 (m, 24H), 1.52 (m, 48H), 1.24 (m, 72H); C NMR
ultrasonication, to produce the disodium salt. To a 4.00 mL acetone
solution of 6 (11.6 mg, 0.010 mmol) was added an aqueous solution
3 3
125 MHz, CD COCD , 22 °C) δ (ppm) 164.0, 160.4, 152.4, 136.5,
35.0, 129.9, 129.3, 128.9, 128.3, 126.6, 125.4, 124.4, 107.0, 103.6,
(
4.00 mL) of disodium salt of 9 (0.010 mmol) dropwise with
1
01.6, 98.2, 95.1, 89.3, 70.9, 70.7, 70.6, 69.6, 69.4, 67.7, 13.5, 7.2;
continuous stirring (5 min). After the resulting mixture was stirred
for another 12 h at room temperature in the open air, a white solid
precipitated. Deionized water was added until no further precipita-
tion was observed. The white precipitate was centrifuged and
3
1
1
P { H} NMR (202.3 MHz, CD
3
COCD
3
, 22 °C) δ (ppm) 14.8 (s,
2
+
J
1
8
6
Pt-P ) 2682 Hz); CSI-TOF-MS m/z 1922.77 [M - 2PF ] , m/z
3
+
3+
294.77 [M - 2PF
6
6
+ K] , m/z 1233.45 [M - 3PF ] , and m/z
4
+
88.81 [M - 4PF
6
] .
washed three times with water and dried in vacuo. Yield 32.0 mg
1
(
8
95%); H NMR (400 MHz, CDCl
3
, 22 °C) δ (ppm) 8.67 (s, 4H),
Acknowledgment. This work was supported by the National
.08 (s, 2H), 7.70 (d, 4H, J ) 8.0 Hz), 7.47 (s, 4H), 7.38 (d, 4H,
J ) 8.0 Hz), 7.14 (t, 2H, J ) 8.0 Hz), 6.49-6.58 (s, 8H), 4.22 (t,
H, J ) 4.8 Hz), 4.14 (t, 8H, J ) 4.8 Hz), 3.88 (m, 16H), 3.66-3.76
Natural Science Foundation of China (20604020, 20774086,
0834004, and J0830413) and National Basic Research Program
2009CB930104).
2
(
8
(
1
3
m, 32H), 1.56 (m, 48H), 1.15 (m, 72H); C NMR (125 MHz,
CDCl , 22 °C) δ (ppm) 171.5, 160.2, 158.7, 136.9, 134.0, 131.6,
30.2, 130.0, 129.7, 128.1, 126.5, 124.5, 122.4, 107.5, 102.1, 101.1,
3
1
13
Supporting Information Available: H NMR, C NMR,
1
7
1.1, 71.1, 70.0, 69.9, 68.7, 67.9, 13.6, 8.0; 31P { H} NMR (202.3
1
31
1
P NMR, mass, and UV-vis spectra of compounds and H
NMR and CSI-TOF-MS spectra of equimolar acetone solutions
MHz, CDCl
3
, 22 °C) δ (ppm) 17.8 (s, JPt-P ) 2908 Hz); CSI-
+
+
TOF-MS m/z 3323.00 [M + H] and 3344.96 [M + Na] . Anal.
Calcd for C136
H, 6.40.
of 1 and 5, and 2 and 5; determination of association constants
of complex 1·5 and other materials. This material is available
2
free of charge via the Internet at http://pubs.acs.org.
212 28 8 4
H O P Pt : C, 49.15; H, 6.43. Found: C, 49.01;
4,6-Bis(4-pyridylethynyl)-m-phenylene-m′-phenylene-32-crown-
10-Based Rhomboid (2). 11 (7.38 mg, 0.010 mmol) was dissolved
JO900461G
3
912 J. Org. Chem. Vol. 74, No. 10, 2009