A [2]catenane and pretzelane based on Sn-porphyrin and crown ether

Article abstract of DOI:10.1002/ejoc.201101145

A [2]catenane and a pretzelane that consist of one aromatic dialkylammonium spacer, one dibenzo-24-crown-8 (DB24C8) unit, and one Sn-porphyrin dihydroxide component were synthesized. In the [2]catenane, dibenzo-24-crown-8 and the Sn-porphyrin dihydroxide

Full text of DOI:10.1002/ejoc.201101145

FULL PAPER
DOI: 10.1002/ejoc.201101145
A [2]Catenane and Pretzelane Based on Sn–Porphyrin and Crown Ether
Min Han,[a] Heng-Yi Zhang,[a] Li-Xu Yang,[a] Zhi-Jun Ding,[a] Rui-Jie Zhuang,[a] and
Yu Liu*[a]
Keywords: Catenanes / Pretzelanes / Porphyrinoids / Crown compounds / Macrocycles
A [2]catenane and a pretzelane that consist of one aromatic
dialkylammonium spacer, one dibenzo-24-crown-8 (DB24C8)
unit, and one Sn–porphyrin dihydroxide component were
synthesized. In the [2]catenane, dibenzo-24-crown-8 and the
Sn–porphyrin dihydroxide are two independent components,
whereas in the pretzelane, dibenzo-24-crown-8 and the Sn–
porphyrin dihydroxide are linked covalently. The interlocked
molecules were obtained by the axial ligation of Sn–por-
phyrin dihydroxide with the resorcinol moieties of both ter-
mini in the aromatic dialkylammonium spacer.
architectures have been constructed through the meso and
β-pyrrol functionalizations of porphyrin. Examples that in-
corporate porphyrin into mechanically interlocked mole-
cules by axial ligation are extremely limited.[12]
In this study, we report the syntheses of the porphyrin-
based macrocycle 1, [2]catenane 2, and pretzelane 3
(Scheme 1). In 1–3, the main macrocycle was obtained by
the axial ligation of Sn–porphyrin dihydroxide with two res-
orcinol moieties of the termini of the aromatic dialkyl-
ammonium spacer. When we replaced Sn–porphyrin dihy-
droxide with an Sn–porphyrin dihydroxide–crown ether
conjugate, 3 was obtained in one step by using a template-
directed protocol.
Introduction
Mechanically interlocked molecules, such as catenanes,[1]
rotaxanes,[2] knots,[1a,3] and Borromean links,[4] based on
molecular recognition and self-assembly have attracted
interest because of their fascinating topological features and
potential as components of molecular-scale devices.[5]
Therefore, it remains necessary to devise new synthetic stra-
tegies for the construction of such systems. Catenanes com-
prise two or more interlocked macrocyclic components, in
which the macrocycles are not linked covalently to each
other. Pretzelanes[6] are bridged [2]catenanes that are con-
nected by covalent bonds, which have also been studied ex-
tensively in recent years. The first pretzelane was synthe-
sized by Vögtle et al.[7] from sulfonamide-based macro-
cycles and catenanes. Stoddart et al.[6,8] developed some do-
nor–acceptor pretzelanes, which were composed of an elec-
tron-deficient tetracationic cyclophane tethered to and me-
chanically interlocked with an electron-rich macrocyclic
polyether. To the best of our knowledge, these are the only
two reported examples of pretzelanes to date.
Porphyrin chromophores are among the most widely
used building blocks in the preparation of synthetic devices
that are able to undergo photoinduced energy- and elec-
tron-transfer processes.[9] Because of their remarkable spec-
troscopic and electrochemical properties as well as easy
substitution and metallation, such chromophores are versa-
tile components for constructing rotaxanes and catenanes.
For example, a series of [2]rotaxanes and [2]catenanes that
incorporate porphyrin, fullerene, and other functional moi-
eties have been described.[10,11] Most of these molecular
Results and Discussion
We designed Sn–porphyrin dihydroxide 6 and Sn–por-
phyrin dihydroxide–crown ether conjugate 9 as the lock.
Sn–porphyrin phenolates[13] are the stable products of the
equilibrium-based condensation reaction of substituted
phenols with Sn–porphyrin dihydroxide in an organic me-
dium. Because of the inherent simplicity of their axial lig-
ation and flexibility of the choice of phenol ligand, we used
Sn–porphyrin phenolates to extend and complement the
construction of molecular architectures. The synthetic
routes to 6 and 9 are shown in Scheme 2. The synthesis of
6 was carried out according to a described procedure.[14]
The starting material for the synthesis of 9 was the free
porphyrin–crown ether conjugate 7, which was obtained af-
ter tedious purification of the product of the condensation
reaction of 4-formyldibenzo-24-crown-8 (1 equiv.) and
benzalaldehyde (3 equiv.) with pyrrole (4 equiv.) in propi-
onic acid. Heating of a mixture of 7 and SnCl2·2H2O in
pyridine afforded the dichlorido complex 8 in 81% yield.
This was converted to the dihydroxide species 9 in 85%
yield by treatment with K2CO3 in THF/H2O with heating.
[a] Department of Chemistry, State Key Laboratory of Elemento-
Organic Chemistry, Nankai University,
Tianjin 300071, P. R. China
Fax: +86-22-2350-3625
E-mail: yuliu@nankai.edu.cn
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201101145.
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M. Han, H.-Y. Zhang, L.-X. Yang, Z.-J. Ding, R.-J. Zhuang, Y. Liu
FULL PAPER
Scheme 1. Structures of 1, 2, and 3.
Scheme 2. Synthesis of 6 and 9.
We designed an axis molecule that bears one resorcin
To prepare macrocycle 1, the reaction of 6 with 1 equiv.
moiety at each terminus and a dialkylammonium binding of 15-H·PF6 was carried out in CHCl3/CH3CN (10:1) at
station in the middle. To choose two triethylene glycol con- room temperature (Figure 1). Although polymerization be-
nectors between the dialkylammonium and resorcinol units tween 6 and 15-H·PF6 could occur in the ring-closing pro-
is basic for CPK models, in which its space can allow an- cess, 1 was successfully produced and isolated by column
other dibenzo-24-crown-8 (DB24C8) to encircle the dialk- chromatography. Encouraged by the fact that DB24C8 is
ylammonium moiety. The synthetic route to 15-H·PF6 is able to complex dialkylammonium ions to form rotaxanes
shown in Scheme 3. The synthesis of 15-H·PF6 started from and pseudorotaxanes,[16] we examined the ring-closing reac-
10, which was prepared from the condensation of 4-hy- tion of 1 in the presence of DB24C8 and obtained 2. Be-
droxybenzaldehyde
with
8-tosyloxy-3,6-dioxaoctanol. cause of the lower temperature of the reaction and the low
Compound 11 was obtained from the reaction of 4-hy- solvent polarity, the formation of a pseudorotaxane be-
droxybenzonitrile with 8-tosyloxy-3,6-dioxaoctanol fol- tween DB24C8 and the dialkylammonium moiety was ex-
lowed by reduction with LiAlH4. Condensation of 10 with pected to be more preferable from the viewpoint of en-
11 followed by reduction gave bis(benzyl)amine 12; thalpy.
(Boc)2O-protected 12 reacted with TsCl to give bis(tosylate)
Macrocycle 1 and [2]catenane 2 were characterized by 1H
14 in 80% yield. Compound 14 reacted with a monopro- NMR spectroscopy and HR mass spectrometry (ESI). The
tected resorcinol derivative[15] in the presence of K2CO3 fol- latter provides convincing evidence for the formation of 1
lowed by deprotection with ethanol/aqueous HCl at room and 2. Figure 2 shows the HR mass spectra of 1 and 2,
temperature and removal of the Boc group with trifluoro- which show molecular ion peaks at m/z = 1408.448 and
acetic acid (TFA) to give free 15 in 85% yield. Acidification 1856.649 corresponding to [1-PF6]+ and [2-PF6]+, respec-
with HCl followed by anion exchange with NH4PF6 af- tively, and their isotopic patterns are in excellent agreement
forded the dialkylammonium salt 15-H·PF6.
with the theoretical distributions. In the 1H NMR spectrum
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A [2]Catenane and Pretzelane Based on Sn–Porphyrin and Crown Ether
Scheme 3. Synthesis of 15-H·PF6.
center and significant changes in the chemical shifts of the
protons of DB24C8 were observed, which suggests that a
DB24C8 moiety encircled the dialkylammonium binding
station of the macrocycle and confirms the formation of 2.
Moreover, the upfield shift of the Hl and Hk signals of the
axis molecule, which may be due to a π–π stacking interac-
tion between the phenyl groups in the salt and the catechol
rings in the crown subunits,[14b] is also in keeping with the
assembly structure. The coordination of DB24C8 restricts
the rotation of the macrocycle around the O–Sn–O axis so
that signals corresponding to the protons of the dialkylam-
monium and porphyrin moieties are split.
Figure 1. Synthesis of 1, 2, and 3.
of 1 (Figure 3c), the most diagnostic signals to judge the
formation of the macrocyclic complex are the resorcinol
resonances, which are shifted significantly to higher field
[Δδ = –5.0 (Ha), –4.75 (Hb), –1.67 (Hc), –0.87 (Hd) ppm].
The significant upfield shifts of these resonances are a result
of the large shielding effect of the porphyrin ring current
and confirm that the resorcinol moieties are linked to the
Sn–porphyrin moiety by Sn–phenoxide coordination.[11,17]
The disappearance of the axial hydroxy proton resonance
at δ = 7.4 ppm is associated with these chemical shift
Figure 2. Calculated (bottom) and experimental (top) HR mass
changes as these protons are exchanged for resorcinol li-
gands. The same resorcinol chemical shift changes were
found in the H NMR spectrum of 2. In addition, a large
spectra (ESI) of 1, 2, and 3.
1
With the successful preparation of 2 in hand, we pre-
downfield shift (by 0.45 ppm) of the signal for the benzylic pared 3. Because 9 comprises a macrocycle and a stopper
methylene protons (Hm) adjacent to the dialkylammonium in one molecule, we were able to synthesize 3 according to
Eur. J. Org. Chem. 2011, 7271–7277
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M. Han, H.-Y. Zhang, L.-X. Yang, Z.-J. Ding, R.-J. Zhuang, Y. Liu
FULL PAPER
Conclusions
We have demonstrated that the synthesis of a new [2]
catenane and pretzelane can be achieved from Sn–por-
phyrin and DB24C8. The new synthetic strategies for 2 and
3 offer the potential for the design and synthesis of even
more intricate systems that incorporate interlocked compo-
nents.
Experimental Section
Instrumentation: NMR spectra were recorded with a Varian 400
spectrometer. Positive-ion matrix-assisted laser desorption ioniza-
tion mass spectrometry was performed with an IonSpec QFT-
MALDI MS. UV/Vis spectra were recorded with a Shimadzu UV-
3600 spectrophotometer equipped with a PTC-348WI temperature
controller. Steady-state fluorescence spectra were recorded with a
VARIAN CARY Eclipse equipped with a VARIAN CARY single-
cell Peltier accessory to keep the temperature at 25 °C. The fluores-
cence quantum yields were recorded with an Edinburgh Analytical
Instruments FLS920 spectrometer.
Figure 3. 1H NMR spectra (400 MHz, CDCl3, 300 K) of (a) 15, (b)
6, (c) 1, (d) 2, (e) 3, and (f) 9.
a template-directed protocol. Compound 9 reacted with 15-
H·PF6 in CHCl3/CH3CN at room temperature to afford 3
(Figure 1). Pretzelane 3 was characterized in a manner sim-
ilar to those for 1 and 2. In the HR mass spectrum of 3,
the molecular ion peak at m/z = 1778.612, which corre-
sponds to [3-PF6]+, was observed, and its isotopic pattern
is in excellent agreement with the theoretical distribution
(Figure 2). In the 1H NMR spectrum of 3, the same chemi-
cal shift changes for the resorcinol moieties as seen in 2 and
the large downfield shift (δ = 0.8 ppm) of the signal of Hm
demonstrate the formation of 3. Compared to those in the
1H NMR spectrum of 2, the signals for Hl, Hk, and Hm in
3 are subject to considerable downfield shifts. This is ex-
plained by the fact that the porphyrin moiety and DB24C8
are connected by a C–C bond in 3, which causes the dialk-
ylammonium moiety to be closer to the edge of the Sn–
porphyrin unit. The dialkylammonium unit is therefore lo-
cated in the deshielding region of the porphyrin ring cur-
rent, which causes these downfield shifts.
Photophysical data of the porphyrin derivatives 1–9 were
measured in CHCl3 solution and are collected in Table S1
(Supporting Information). These data provide further evi-
dence for the formation of the desired molecular architec-
tures. UV/Vis spectroscopy is a powerful tool for monitor-
ing the metallation of porphyrins. The UV/Vis spectra of 4
and 7 showed characteristic absorption bands for free por-
phyrin with Soret bands at 418 and 420 nm, respectively.
Synthesis of 5-[4-(Dibenzo-24-crown-8)]-10,15,20-triphenylporphyrin
(7): A mixture of 4-formyldibenzo-24-crown-8 (4.0 g, 8.4 mmol)
and propionic acid (600 mL) was heated at 110 °C with stirring.
Benzaldehyde (2.7 mL, 25.2 mmol) and pyrrole (2.4 mL, 38 mmol)
were successively and slowly added to this solution. The resulting
mixture was heated under reflux for 1.5 h, allowed to cool to room
temperature, and the solvents were evaporated to dryness. The resi-
due was neutralized with aqueous ammonia, filtered through a
glass frit, and washed several times with water. The crude material
was extracted with CHCl3 and purified by column chromatography
on dry silica gel. The desired product was isolated on elution with
CHCl3/CH3OH (100:1). Evaporation of the solvent afforded 7 as
purple powder (0.5 g; 6%). 1H NMR (400 MHz, CDCl3): δ = –2.78
(s, 2 H), 3.90–3.92 (m, 4 H), 3.97–3.98 (m, 6 H), 4.00–4.01 (m, 4
H), 4.12 (t, 2 H), 4.19 (t, 2 H), 4.23 (t, 2 H), 4.29 (t, 2 H), 6.90–
6.95 (m, 4 H), 7.22 (d, J = 8.0 Hz, 1 H), 7.70–7.81 (m, 11 H), 8.21
(d, J = 6.8 Hz, 6 H), 8.84–8.95 (m, 8 H) ppm. 13C NMR (100 MHz,
CDCl3): δ = 149.0, 148.7, 146.9, 142.2, 135.2, 134.6, 128.0, 127.8,
126.7, 121.5, 120.5, 120.2, 120.1, 119.9, 114.0, 111.7, 71.6, 71.5,
71.4, 70.1, 70.1, 70.0, 70.0, 69.7, 69.6, 69.5, 69.4 ppm. ESI-MS: m/z
= 985.68 [M + H]+. HRMS (ESI): calcd. for C62H56N4O8 [M]+
984.410; found 984.413.
Synthesis
of
Dichlorido{5-[4-(dibenzo-24-crown-8)]-10,15,20-
triphenylporphyrinato}tin(IV) (8): Compound 7 (300 mg, 0.3 mmol)
was heated under reflux with stirring with finely ground
SnCl2·2H2O (344 mg, 1.5 mmol) in pyridine (50 mL) overnight.
Complete Sn insertion was confirmed by UV-spectroscopic exami-
Generally, both the position and number of bands changes nation of a drop of the reaction mixture diluted with dichlorometh-
ane or chloroform. The crude product was precipitated by the ad-
dition of water and collected by vacuum filtration through Celite.
Methanol was washed through the Celite plug to remove excess
water, followed by chloroform to extract the porphyrin. The chloro-
form filtrate was washed with aqueous hydrochloric acid (6 m, 2ϫ
10 mL) and water (2ϫ 10 mL) and dried (anhydrous sodium sul-
fate). The solvent was evaporated, and the residue was purified by
chromatography on silica gel (CHCl3/methanol, 20:1) to afford 8
(350 mg) as a purple solid in 100% yield. 1H NMR (400 MHz,
CDCl3): δ = 3.90–3.94 (m, 4 H), 3.94–3.99 (m, 6 H), 4.00–4.03 (m,
4 H), 4.14 (t, 2 H), 4.20 (t, 2 H), 4.23 (t, 2 H), 4.27 (t, 2 H), 4.48
upon metallation. The bathochromic shifts of the Soret
bands, the disappearance of four Q-bands in the free-base
porphyrin, and the appearance of two new Q-bands in the
metalloporphyrins 1, 2, 3, 5, 6, 8, and 9 confirm the forma-
tion of the metallated products.[18] Metallation of the por-
phyrin derivatives also causes a blueshift of the emission
bands and a decrease of the fluorescence intensity. Com-
pared with free porphyrins 4 and 7, Sn–porphyrin deriva-
tives showed lower quantum yields and lifetimes owing to
the heavy-atom effect of the metal.
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A [2]Catenane and Pretzelane Based on Sn–Porphyrin and Crown Ether
(t, 2 H), 6.90–6.93 (m, 4 H), 7.28–7.29 (m, 1 H), 7.79–7.86 (m, 11
H), 8.31 (d, J = 6.4 Hz, 6 H), 9.16–9.26 (m, 8 H) ppm. HRMS
(ESI): calcd. for C62H54Cl2N4O8Sn [M]+ 1173.242; found 1173.246.
(35 mmol, 1.33 g) was added in small portions over 30 min. The
reaction mixture was stirred at –5 °C for 2 h and at 0 °C for 1 h.
The reaction was quenched by addition of water (100 mL). The
product was extracted with CH2Cl2 (3ϫ 100 mL), and the com-
bined CH2Cl2 extracts were washed with water (4ϫ 100 mL) and
dried with Na2SO4. The solvent was evaporated, and the residue
was purified by chromatography on silica gel (CH2Cl2/methanol,
10:1) to afford 12 (1.6 g, 57%) as a colorless oil. 1H NMR
(400 MHz, CDCl3): δ = 3.61 (t, 4 H), 3.68–3.73 (m, 16 H), 3.86 (t,
4 H), 4.12 (t, 4 H), 6.87 (d, J = 8.8 Hz, 4 H), 7.23 (d, J = 8.8 Hz,
4 H) ppm. ESI-MS: m/z = 494.23 [M + H]+.
Synthesis of Dihydroxido{5-[4-(dibenzo-24-crown-8)]-10,15,20-tri-
phenylporphyrinato}tin(IV) (9): Potassium carbonate (1.7 g,
12 mmol) and 8 (350 mg, 0.3 mmol) were dissolved in a mixture of
tetrahydrofuran (THF, 160 mL) and water (40 mL) and heated un-
der reflux for 3 h. The organic solvent was removed, and the aque-
ous layer was extracted with dichloromethane (60 mL). The organic
layer was washed with water (2ϫ 40 mL), dried with anhydrous
sodium sulfate, filtered, and the solvent was removed to give the
crude product, which was purified by chromatography on silica gel
to give 9 (315 mg, 90%) as a metallic-purple crystalline solid. 1H
NMR (400 MHz, CDCl3): δ = –7.50 to –7.38 (br., 2 H), 3.90–3.95
(m, 4 H), 3.98–4.00 (m, 6 H), 4.02–4.04 (m, 4 H), 4.15 (t, 2 H),
4.22 (t, 2 H), 4.24 (t, 2 H), 4.29 (t, 2 H), 4.45 (t, 2 H), 6.90–6.95
(m, 4 H), 7.29–7.30 (m, 1 H), 7.82–7.88 (m, 11 H), 8.30–8.50 (m,
6 H), 9.11–9.23 (m, 8 H) ppm. 13C NMR (100 MHz, CDCl3): δ =
149.1, 149.0, 147.1, 147.0, 146.7, 146.7, 141.3, 135.2, 134.2, 132.9,
132.7, 132.6, 128.5, 128.3, 127.1, 121.5, 121.3, 121.2, 121.2, 120.9,
114.1, 111.8, 71.7, 71.6, 71.5, 71.4, 70.1, 70.1, 70.0, 69.7, 69.6,
69.5 ppm. ESI-MS: m/z = 1137.49 [M + H]+. HRMS (ESI): calcd.
for C62H56N4O10Sn [M]+ 1136.312; found 1136.317.
Synthesis of N-Boc-bis(p-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}-
benzyl)amine (13): Di-tert-butyl hydrogen carbonate (3.3 mmol,
0.7 g) dissolved in chloroform (15 mL) was added dropwise to a
solution of 12 (3.3 mmol, 1.6 g) in chloroform (25 mL) with stirring
and cooling in an ice bath over 3 h. The reaction mixture was
stirred at room temperature for 12 h and was washed with water
(3ϫ 50 mL). The organic phase was dried with Na2SO4. The sol-
vent was evaporated, and the residue was purified by chromatog-
raphy on silica gel (CH2Cl2/methanol, 10:1) to afford 13 (1.8 g,
1
92%) as a colorless oil. H NMR (400 MHz, CDCl3): δ = 1.49 (s,
9 H), 3.62 (t, 4 H), 3.70–3.74 (m, 12 H), 3.87 (t, 4 H), 4.13 (t, 4
H), 4.22 (s, 2 H), 4.31 (s, 2 H), 6.86 (d, J = 8.8 Hz, 4 H), 7.10 (d,
J = 8.8 Hz, 4 H) ppm. ESI-MS: m/z = 616.41 [M + Na]+.
Synthesis of p-{2-[2-(2-Hydroxyethoxy)ethoxy]ethoxy}benzaldehyde
(10): A mixture of 4-hydroxybenzaldehyde (5.5 g, 45 mmol), 8-tos-
yloxy-3,6-dioxaoctanol (15 g, 49.3 mmol), and K2CO3 (13.8 g,
100 mmol) in dry acetonitrile (300 mL) was heated to reflux under
N2 overnight. The reaction mixture was cooled to room tempera-
ture, filtered, and washed with dichloromethane. The filtrate was
concentrated, and the crude product was purified by column
chromatography on silica gel (EtOAc/petroleum ether, 1:1) to af-
ford 10 (5.15 g, 45%) as a colorless liquid. 1H NMR (400 MHz,
CDCl3): δ = 3.61 (t, 2 H), 3.70–3.74 (m, 6 H), 3.89 (t, 2 H), 4.21
(t, 2 H), 7.02 (d, J = 8.8 Hz, 2 H), 7.82 (d, J = 8.8 Hz, 2 H), 9.87
(s, 1 H) ppm.
Synthesis of N-Boc-bis(p-{2-[2-(2-tosyloxyethoxy)ethoxy]ethoxy}-
benzyl)amine (14): To a mixture of 13 (1.8 g, 3 mmol) and sodium
hydroxide (0.48 g, 12 mmol) in THF/H2O (10/10 mL) in an ice bath
was added tosyl chloride (1.23 g, 6.5 mmol) in THF (20 mL) drop-
wise over 3 h. The mixture was stirred overnight before THF was
evaporated under reduced pressure. The residue was extracted with
ethyl acetate and dried with anhydrous magnesium sulfate. After
the solvent had been removed in vacuo, the crude product was puri-
fied by column chromatography on silica gel (EtOAc/petroleum
ether, 2:1) to afford 14 (2.7 g, 95%) as a colorless oil. 1H NMR
(400 MHz, CDCl3): δ = 1.49 (s, 9 H), 2.43 (s, 6 H), 3.61 (t, 4 H),
3.66 (t, 4 H), 3.70 (t, 4 H), 3.82 (t, 4 H), 4.10 (t, 4 H), 4.16 (t, 4
H), 4.22 (s, 2 H), 4.31 (s, 2 H), 6.85 (d, J = 8.4 Hz, 4 H), 7.11 (dd,
4 H), 7.32 (d, J = 8.0 Hz, 4 H), 7.79 (d, J = 8.4 Hz, 4 H) ppm.
ESI-MS: m/z = 924.50 [M + Na]+.
Synthesis of p-{2-[2-(2-Hydroxyethoxy)ethoxy]ethoxy}benzylamine
(11): A mixture of 4-hydroxybenzonitrile (5.3 g, 45 mmol), 8-tos-
yloxy-3,6-dioxaoctanol (15 g, 49.3 mmol), and K2CO3 (13.8 g,
100 mmol) in dry acetonitrile (300 mL) was heated to reflux under
N2 overnight. The reaction mixture was cooled to room tempera-
ture, filtered, and washed with dichloromethane. The filtrate was
concentrated, and the crude product was purified by column
chromatography on silica gel (EtOAc/petroleum ether, 2:1) to af-
ford p-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}benzonitrile (4.5 g,
39%). 1H NMR (400 MHz, CDCl3): δ = 3.61 (t, 2 H), 3.68–3.74
(m, 6 H), 3.88 (t, 2 H), 4.17 (t, 2 H), 6.98 (d, J = 8.8 Hz, 2 H),
7.58 (d, J = 8.8 Hz, 2 H) ppm. To a solution of p-{2-[2-(2-hydroxy-
ethoxy)ethoxy]ethoxy}benzonitrile (4.5 g, 17.9 mmol) in THF
(260 mL) was added LiAlH4 (1.8 g, 47.4 mmol). After stirring at
room temperature for 3 h, the reaction mixture was quenched with
water and extracted with dichloromethane. The organic layer was
dried with anhydrous sodium sulfate. The solvent was evaporated,
and the residue was purified by chromatography on silica gel
(CH2Cl2/methanol, 2:1) to afford 11 (4.05 g, 90%). 1H NMR
(400 MHz, CDCl3): δ = 3.60 (t, 2 H), 3.68–3.73 (m, 8 H), 3.78 (s,
2 H, NH2), 3.85 (t, 2 H), 4.12 (t, 2 H), 6.89 (d, J = 8.4 Hz, 2 H),
7.20 (d, J = 8.4 Hz, 2 H) ppm.
Synthesis of Bis[p-(2-{2-[2-(3-phenyl)ethoxy]ethoxy}ethoxy)benzyl]-
amine (15): A suspension of cesium carbonate (4.0 g, 12 mmol) in
dry acetonitrile (50 mL) was stirred vigorously for 10 min and then
heated to 100 °C under N2. To this mixture was added dropwise a
solution of mono-THP-protected resorcinol (1.4 g, 7.2 mmol) and
14 (2.7 g, 3.0 mmol) in dry acetonitrile (50 mL). The reaction mix-
ture was stirred at 100 °C for 1 d. After cooling to ambient tem-
perature, the mixture was filtered and washed with CH2Cl2
(60 mL). The filtrate was concentrated under reduced pressure to
give a residue, which was purified by column chromatography on
silica gel (EtOAc/petroleum ether, 1:1) to afford 15 (2.2 g, 78%) as
a colorless oil. This oil (1.0 g, 1 mmol) was dissolved in methanol
(15 mL) under N2 and stirred vigorously at room temperature. To
this was added dropwise a solution of HCl (1 m, 3 mL). The mix-
ture was stirred at room temperature overnight. Methanol was
evaporated under reduced pressure, and the residue was extracted
with ethyl acetate and dried with anhydrous magnesium sulfate.
The filtrate was concentrated under reduced pressure to give an
intermediate as a colorless oil. TFA (4.4 mL) was added dropwise
Synthesis of Bis(p-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}benzyl)-
amine (12): Triethylamine (2.5 mmol, 0.35 mL), MgSO4 (8.3 mmol, to a solution of the intermediate in chloroform (5 mL) with stir-
1 g), and 10 (6.0 mmol, 1.56 g) were added to a solution of 11
(5.0 mmol, 1.3 g) in methanol (15 mL). The reaction mixture was
stirred at room temperature for 10 h and cooled to –5 °C. NaBH4
ring. The reaction mixture was stirred at room temperature for 12 h
and was then washed with NaOH (1 m, 3ϫ 50 mL) until the or-
ganic phase had become colorless. The organic phase was dried
Eur. J. Org. Chem. 2011, 7271–7277
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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M. Han, H.-Y. Zhang, L.-X. Yang, Z.-J. Ding, R.-J. Zhuang, Y. Liu
FULL PAPER
(MgSO4), and the solvent was evaporated. The residue was sub-
jected to column chromatography on silica gel (CHCl3/methanol,
10:1) to obtain 15. H NMR (400 MHz, CDCl3): δ = 3.48 (s, 1 H,
Synthesis of 3: A solution of 9 (60 mg, 0.05 mmol) in dry CHCl3
(50 mL) was stirred vigorously at room temperature under N2. To
this was added dropwise a solution of 15-H·PF6 (45 mg,
1
NH), 3.69 (t, 4 H, Hg), 3.73–3.75 (m, 8 H, Hh + Hf), 3.78 (t, 4 H, 0.05 mmol) in dry acetonitrile (5 mL). The reaction mixture was
Hi), 3.84 (t, 4 H, Hm), 3.89 (t, 4 H, He), 4.10 (t, 4 H, Hj), 5.29 (s, stirred at room temperature overnight. After the solvent had been
2 H, OH), 6.15 (t, 2 H, Hb), 6.41 (d, 4 H, Ha + Hd), 6.84 (d, J =
removed in vacuo, the crude product was purified by column
8.8 Hz, 4 H, Hk), 7.06 (t, 2 H, Hc), 7.20 (d, J = 8.8 Hz, 4 H, Hl) chromatography on basic alumina (CHCl3) to afford 3 (25 mg,
ppm. ESI-MS: m/z = 678.29 [M + H]+. After a protonation and
ion-exchange process, 15-H·PF6 was afforded as white precipitate
(0.71 g, total yield 82%). H NMR (400 MHz, CD3CN): δ = 3.66–
25%) as a purple solid. 1H NMR (400 MHz, CDCl3): δ = 1.20–
1.43 (m, 4 H, Ha + Hb), 2.80–4.83 (m, 48 H, –OCH2CH2O–), 4.50–
4.90 (m, 2 H, Hm), 5.19–5.60 (m, 4 H, Hd + Hc), 6.85–7.00 (m, 6
1
3.70 (m, 8 H, Hg + Hh), 3.76–3.80 (m, 8 H, Hf + Hi), 4.04–4.10 H, Hk + Ph-H), 7.10 (d, J = 8.4 Hz, 2 H, Hl), 7.14 (d, J = 8.4 Hz,
(m, 4 H, Hm), 4.12–4.20 (m, 8 H, He + Hj), 6.37–6.45 (m, 6 H, Ha
1 H, Ph-H), 7.33 (d, J = 8.4 Hz, 2 H, Hk), 7.55 (d, J = 8.4 Hz, 2
+ Hb + Hd), 6.98 (d, J = 8.8 Hz, 4 H, Hk), 7.10 (t, 2 H, Hc), 7.39
H, Hl), 7.75–7.90 (m, 11 H, Ph-H), 8.12–8.14 (m, 2 H, Ph-H), 8.34–
(d, J = 8.4 Hz, 4 H, Hl) ppm. 13C NMR (100 MHz, CD3CN): δ = 8.45 (m, 4 H, Ph-H), 8.90–9.22 (m, 8 H, β-H) ppm. 13C NMR
160.36, 160.07, 158.35, 132.09, 130.35, 122.68, 115.05, 108.04,
106.15, 101.96, 101.92, 70.59, 70.55, 69.54, 69.42, 67.79, 67.45 ppm.
(100 MHz, CD3CN): δ = 161.2, 160.1, 159.1, 158.4, 158.4, 148.3,
148.1, 148.0, 147.2, 147.8, 147.6, 141.5, 141.4, 141.3, 135.8, 135.7,
135.6, 135.5, 133.8, 133.7, 133.0, 132.7, 132.2, 132.1, 131.9, 131.0,
129.8, 129.7, 128.3, 128.2, 128.2, 127.5, 123.0, 122.7, 122.1, 116.5,
115.9, 111.0, 108.8, 107.0, 103.8, 102.7, 72.1, 71.8, 71.6, 71.4, 71.4,
71.3, 71.2, 71.0, 70.6, 70.3, 70.3, 70.1, 68.9, 68.7, 68.3, 67.6,
67.4 ppm. HRMS (ESI): calcd. for C100H100N5O18Sn [3-PF6]+
1778.6107; found 1778.612.
ESI-MS: m/z
=
678.4 [15-H]+. HRMS (ESI): calcd. for
C38H48NO10 [15-H]+ 678.328; found 678.327.
Synthesis of 1: A solution of 6 (57 mg, 0.07 mmol) in dry CHCl3
(50 mL) was stirred vigorously at room temperature under N2. To
this was added dropwise
a solution of 15-H·PF6 (50 mg,
0.07 mmol) in dry acetonitrile (5 mL). The reaction mixture was
stirred at room temperature overnight. After the solvent had been
removed in vacuo, the crude product was purified by column
chromatography on basic alumina (CHCl3) to afford 1 (30 mg,
30%) as a purple solid. 1H NMR (400 MHz, CDCl3): δ = 1.30–
1.50 (m, 4 H, Ha + Hb), 3.16 (s, 4 H, He), 3.45 (s, 4 H, Hf), 3.56
(s, 4 H, Hg), 3.62 (s, 4 H, Hh), 3.68 (s, 4 H, Hi), 3.77 (s, 4 H, Hm),
4.03 (s, 4 H, Hj), 5.39 (d, J = 6.0 Hz, 2 H, Hc), 5.53 (d, J = 7.2 Hz,
2 H, Hd), 6.80–6.90 (m, 4 H, Hk), 7.10–7.25 (m, 2 H, Hl), 7.70–
7.90 (m, 12 H, Ph-H), 8.10–8.30 (m, 8 H, Ph-H), 9.05–9.20 (m, 8
H, β-H) ppm. 13C NMR (100 MHz, CDCl3): δ = 157.3, 155.9,
147.5, 147.1, 141.2, 141.0, 135.2, 135.1, 135.0, 132.8, 132.7, 132.1,
128.7, 128.6, 128.5, 127.2, 127.2, 127.0, 126.5, 126.5, 122.0, 115.1,
115.0, 114.8, 110.6, 110.6, 110.6, 104.1, 103.6, 71.1, 71.0, 70.87,
69.97, 69.94, 69.78, 69.74, 67.9, 67.8, 67.7, 67.6, 66.5, 66.5 ppm.
HRMS (ESI): calcd. for C82H74N5O10Sn [1-PF6]+ 1408.4473; found
1408.448.
Supporting Information (see footnote on the first page of this arti-
cle): Experimental procedures and characterization for all com-
pounds, absorption spectra and emission spectra of porphyrin de-
rivatives.
Acknowledgments
This work was supported by the 973 Program (2011CB932500) of
the National Natural Science Foundation of China (NSFC) (Nos.
20932004, 20772063, and 20972077).
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6.41 (m, 2 H, Hk), 6.47–6.50 (m, 2 H, Hl), 6.66–6.70 (m, 2 H, Hk),
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8.20 (m, 4 H, Ph-H), 8.30–8.40 (m, 4 H, Ph-H), 9.04–9.16 (m, 8 H,
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156.1, 156.0, 149.3, 147.7, 147.5, 147.4, 147.3, 147.1, 141.1, 141.1,
141.0, 141.0, 135.3, 135.2, 135.1, 133.1, 133.0, 132.9, 132.8, 132.8,
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69.7, 69.6, 69.3, 69.2, 68.4, 68.4, 68.1, 67.7, 67.6, 66.7, 66.5 ppm.
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found 1856.649.
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Received: August 4, 2011
Published Online: November 2, 2011
Eur. J. Org. Chem. 2011, 7271–7277
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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7277