A novel amphiphilic pincer palladium complex: Design, preparation and self-assembling behavior

Article abstract of DOI:10.1039/c1dt10556f

Amphiphilic pincer palladium complexes bearing hydrophilic and hydrophobic side chains on the planar NCN palladium pincer backbone were designed and prepared via the ligand introduction route. The complexes self-assembled under aqueous conditions to form

Full text of DOI:10.1039/c1dt10556f

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This article is published as part of the Dalton Transactions themed issue entitled:
Pincers and other hemilabile ligands
Guest Editors Dr Bert Klein Gebbink and Gerard van Koten
Published in issue 35, 2011 of Dalton Transactions
Image reproduced with permission of Jun-Fang Gong
Articles in the issue include:
PERSPECTIVE:
Cleavage of unreactive bonds with pincer metal complexes
Martin Albrecht and Monika M. Lindner
Dalton Trans., 2011, DOI: 10.1039/C1DT10339C
ARTICLES:
Pincer Ru and Os complexes as efficient catalysts for racemization and deuteration of alcohols
Gianluca Bossi, Elisabetta Putignano, Pierluigi Rigo and Walter Baratta
Dalton Trans., 2011, DOI: 10.1039/C1DT10498E
Mechanistic analysis of trans C–N reductive elimination from a square-planar macrocyclic aryl-
copper(III) complex
Lauren M. Huffman and Shannon S. Stahl
Dalton Trans., 2011, DOI: 10.1039/C1DT10463B
CSC-pincer versus pseudo-pincer complexes of palladium(II): a comparative study on
complexation and catalytic activities of NHC complexes
Dan Yuan, Haoyun Tang, Linfei Xiao and Han Vinh Huynh
Dalton Trans., 2011, DOI: 10.1039/C1DT10269A
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PAPER
A novel amphiphilic pincer palladium complex: design, preparation and
self-assembling behavior†
Go Hamasaka,a Tsubasa Mutoa,b and Yasuhiro Uozumi*a,b,c
Received 1st April 2011, Accepted 5th July 2011
DOI: 10.1039/c1dt10556f
Amphiphilic pincer palladium complexes bearing hydrophilic and hydrophobic side chains on the
planar NCN palladium pincer backbone were designed and prepared via the ligand introduction route.
The complexes self-assembled under aqueous conditions to form vesicles with bilayer membranes
containing palladium species. The catalytic activity of the vesicles in the Miyaura–Michael reaction in
water was investigated.
Introduction
Palladium complexes containing monoanionic terdentate ligands,
so-called pincer complexes, have received much attention as
catalysts in synthetic organic chemistry1 and also as organometal-
lic compounds in the field of materials science.2 Recently, we
developed a new strategy for the synthesis of pincer palladium
complexes, the ligand introduction route, in which the metal is
introduced onto the aromatic ring prior to the construction of
the ligand units.3,4 This strategy enabled us to prepare a novel
class of pincer palladium complexes having sterically demanding
and/or chemically unstable functional groups. Representative
examples are shown in Scheme 1. In this manner, NCN palladium
pincer complexes 2 bearing a planar pincer core moiety and
imine ligand units (-CH NR) were prepared from the 2,6-
dialdehyde precursor 1 via dehydrative condensation with primary
amines under mild oxidative conditions (Scheme 1).3 In contrast,
Scheme 1 Preparation of NCN Pincer Palladium Complexes via the
metallation of the pincer ligands 3 via oxidative addition [from 3a
(X = halogen)] or CH-metallation [from 3b (X = H)] resulted in
poor yields of the desired pincer complexes 2 because of the steric
bulkiness and/or the chemical reactivity of the imine units.
The self-assembling construction of potentially functionalized,
highly-ordered molecular architectures via non-covalent interac-
tions among the monomer units is rapidly generating interest from
a wide range of chemists.5 In particular, it has been reported
that organic molecules having rigid planar backbones with both
hydrophobic and hydrophilic side chains often form bilayer
assemblages.6 If hydrophobic and hydrophilic side chains are
incorporated onto the planar NCN palladium pincer backbone,
theresultingamphiphilic palladiumpincer complexes wouldadopt
Ligand Introduction Route.
a self-assembled architecture having catalytic activity.7,8 We report
here the design, preparation, and self-assembling vesicle formation
of amphiphilic palladium pincer complexes and their application
to the Miyaura–Michael reaction9 in water.
Results and Discussion
The pincer palladium complexes 4 and 5 having pairs of hy-
drophobic dodecyl chains and hydrophilic tri(ethylene glycol)
(TEG) chains, located opposite to one another on the rigid planar
backbone, were designed and prepared for use in the formation of
self-assembled molecular architectures (Fig. 1 and 2).
aInstitute for Molecular Science, Myodaiji, Okazaki, 444-8787, Japan.
E-mail: uo@ims.ac.jp; Fax: (+81)564-59-5574
Preparation of Pincer Complexes 4 and 5
bThe Graduate School for Advanced Studies, Myoudaiji, Okazaki, 444-8787,
Japan
The amphiphilic NCN pincer palladium complexes 4 and 5
could ideally be obtained by dehydrative condensation of their
2,6-dialdehyde precursors 6 and 7 and primary amines 8 and
9, respectively, via the ligand introduction route (Scheme 2).
cRiken, Hirosawa, Wako, 351-0198, Japan. E-mail: uo@riken.jp
† Electronic supplementary information (ESI) available: 1H and 13C NMR
spectra of all new compounds. See DOI: 10.1039/c1dt10556f
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 8859–8868 | 8859
©

Scheme 2 Synthetic Precursors of Pincer Complexes 4 and 5.
Fig. 1 Design of Amphiphilic Pincer Palladium Complexes.
Fig. 2 Concept of Vesicle Formation via Self-Assembly of Amphiphilic
Scheme 3 Preparation of Precursor 6.
Pincer Complexes.
The precursor 6 was prepared from the phenol 10 in nine
steps (Scheme 3). Thus, phenol 10 was protected with a
methoxymethyl (MOM) group (73%) and the resulting MOM
ether 11 was treated with N-bromosuccinimide under radical
conditions to give 1,5-bis(bromomethyl)arene 12 in 54% yield. The
hydrophilic methoxy[tri(ethylene glycol)] [CH3(OCH2CH2)3OH;
8860 | Dalton Trans., 2011, 40, 8859–8868
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The Royal Society of Chemistry 2011
©

MeOTEGOH] units were incorporated at the benzylic positions
to give the 1,5-bis(MeOTEGOCH2)arene 13 in 67% yield.
The methoxycarbonyl groups of 13 were converted to CHO
groups (compound 15) via LiAlH4 reduction to 14 (93%) and
subsequent Swern oxidation (92%). After removal of the O-
MOM group, the resulting phenol 16 was treated with triflic
anhydride to give the O-Tf ester 17. Complexation of the triflate
17 was carried out with dipalladiumtris(dibenzylideneacetone)
[Pd2(dba)3] in the presence of triphenylphosphine to afford
an arylpalladium[bis(triphenylphosphine)] complex, which was
subsequently treated with lithium chloride to provide the desired
arylpalladium chloride bis(triphenylphosphine) complex 6 bear-
ing formyl groups at both ortho positions.
We prepared precursor 7 with hydrophilic and hydrophobic
groups in the opposite orientation to those of precursor 6
from 3,5-dibromophenol (18) in seven steps (Scheme 4). The
hydrophobic dodecyl groups were introduced at the 3,5-positions
of compound 19, which was readily obtained from 18 by treat-
ment with dihydropyran, through palladium-catalyzed Grignard
cross-coupling with dodecylmagnesium bromide, to afford 3,5-
bis(dodecyl)phenol (20) in 71% yield. After removal of the O-THP
moiety, formyl groups were introduced at the 2,6-positions of the
phenol with hexamethylenetetramine to give the diformylated phe-
nol 22 in 13% yield. The phenol was treated with triflic anhydride
and the resulting triflate 23 (43%) underwent complexation with
Pd2(dba)3/PPh3 followed bytreatmentwith LiClto give the desired
precursor 7 in 94% yield.
Scheme 5 Preparation of Pincer Complexes 4 and 5.
6 reacted with 10 equiv of the aniline 8 bearing a hydrophobic
4-alkyl substituent in refluxing acetonitrile for 72 h followed by
treatment with urea-hydroperoxide at 50 ◦C to give an 85% yield
of the amphiphilic pincer palladium complex 4 as an amorphous
material. The hydrophobic precursor 7 underwent a similar ligand
introduction protocol with the hydrophilic aniline 9 to afford
the amphiphilic pincer palladium complex 5 having the opposite
orientation of the hydrophilic and hydrophobic side chains, also
as an amorphous material in 76% isolated yield. The pincer
complexes 4 and 5 were formed through condensation of the 2,6-
formyl groups of 6 and 7 with primary amines 8 and 9 affording the
corresponding intermediates A, and subsequent ligand exchange
by the resulting imine functionalities constructing the Pd–N
bonds. Irreversible trapping of PPh3 ligands liberated from a
possible intermediate A by oxidation with urea-hydrogenperoxide
is essential to promote this pincer complexation process.3
Self-Assembly of Pincer Complexes 4 and 5
With the amphiphilic pincer palladium complexes 4 and 5 in
hand, we next turned our attention to demonstrating their self-
assembling potential. After thorough screening, we were pleased
to find that both complexes 4 and 5 exhibited good assembling
potential under aqueous conditions. Thus, to an acetonitrile
solution of 4 was added water (H2O/CH3CN = 9/1) and the
resulting aqueous mixture was concentrated at 80 ◦C for 6 h,
during which time acetonitrile was slowly vaporized, to afford
a pale yellow aqueous suspension.10 The resulting suspension
was cooled and centrifuged (4000 rpm, 15 min) to give nano-
precipitates. The precipitate was diluted with water and studied
by dynamic light scattering (DLS) to demonstrate the formation
of the vesicle 4vscl (average diameter = 463 nm) [Fig. 3(a)]. The
amphiphilic pincer complex 5 was treated in water at 60 ◦C for
Scheme 4 Preparation of Precursor 7.
Pincer complexation of 6 and 7 was achieved by ligand
introduction with the hydrophobic aniline 8 and the hydrophilic
aniline 9, respectively (Scheme 5). Thus, the hydrophilic precursor
Fig. 3 Histograms of the Size Distributions of (a) 4 and (b) 5.
Dalton Trans., 2011, 40, 8859–8868 | 8861
This journal is
The Royal Society of Chemistry 2011
©

4 h, and the resulting aqueous mixture was cooled to ambient
10
temperature and vortexed to afford an aqueous slurry of 5vscl
.
A
dynamic light scattering (DLS) study of the slurry demonstrated
that the vesicle 5vscl having an average diameter of 550 nm was
formed [Fig. 3(b)].
In order to determine the morphologies of bilayer vesicles of
4vscl and 5vscl, we performed atomic force microscopy (AFM),
transmission electron microscopy (TEM) and scanning electron
microscopy (SEM) analyses. The samples for AFM, TEM and
SEM studies were prepared by dropping the suspensions of
4vscl and 5vscl in water onto a freshly cleaved mica surface and
a copper grid covered with a carbon membrane and a silicon
wafer, respectively, followed by drying under ambient conditions.
The spherical morphologies of 4vscl and 5vscl were confirmed by
AFM and SEM images [Fig. 4(a) and (b) and Fig. 6(a) and
(b), respectively]. TEM observation of vesicular composites 4vscl
and 5vscl showed that these composites were hollow structures
and the thicknesses of both the vesicle membranes were observed
to be ca. 6–7 nm [Fig. 5(a) and (b)]. These data are consistent
with those of the bilayer membranous structures of 4 and 5
each having both monomer lengths of ca. 2.8 nm in their
structures.11
Fig. 6 SEM Images of (a) 4 and (b) 5.
The incorporation of the fluorescent reagent, fluorescein, into
4vscl revealed a hollow structure with an inner hydrophobic region
in the exterior membrane.10b Thus, when the isolated 4vscl was
exposed to fluorescein under aqueous conditions, the fluorescent
vesicles, 4vscl/fluorescein, were obtained [Fig. 7(a) and 8(a)]. A
similar hollow structure of 5vscl was also observed microscopically
with the same fluorescence reagent [Fig. 7(b) and 8(b)].
Fig. 7 Fluorescence microscopic images of (a) 4/Fluorescein and (b) 5/.
Fig. 4 AFM Images of (a) 4 and (b) 5.
Fig. 8 CLSM images of (a) 4/Fluorescein and (b) 5/Fluorescein.
These experiments demonstrated that the structure of the vesicle
4vscl was similar to that of 5vscl. Therefore, the inversion of the
positions of hydrophobic and hydrophilic groups on the pincer
backbone did not strongly influence vesicle formation via self-
assembly of 4 and 5.
Miyaura–Michael Reaction in Water
With the desired vesicles 4vscl and 5vscl in hand, we next explored
their catalytic potential for the Miyaura–Michael reaction9 of 2-
cyclohexene-1-one (24) with sodium tetraphenylborate (25; Table
1). The vesicle 4vscl (2 mol% Pd) promoted the Miyaura–Michael
reaction of 24 with 25 (1.5 equiv) in water to give the desired
arylated product 26 in 19% yield in 12 h with >99% reaction
selectivity (entry 1), whereas monomer 4 afforded only a 5%
yield of 26 with much lower selectivity (entry 2). Thus, only a
slight promotion of the Miyaura–Michael reaction in water was
Fig. 5 TEM Images of (a) 4 and (b) 5.
8862 | Dalton Trans., 2011, 40, 8859–8868
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©

spectra were recorded in CDCl3 at 25 ◦C. EI-TOF-MS analysis
was carried out in a JEOL JMS-T100GC. ESI mass spectra
were recorded on a JEOL JMS-T100LC spectrometer. FAB
mass spectra were recorded on a JEOL JMS-777V spectrometer;
meta-nitrobenzyl alcohol was used as a matrix. MALDI mass
spectra were recorded on an Applied Biosystems Voyager DE-STR
spectrometer; dithranol was used as a matrix. Elemental analyses
were performed on Yanaco CHN Corder MT-6. Melting points
were determined using a Yanaco micro melting point apparatus
MP-J3 and are uncorrected. IR spectra were obtained using a
JASCO FT/IR-460plus spectrometer in ATR mode. Dynamic
light scatterings (DLS) were observed on an Ohtsuka electronics
Co. DLS-6100P system using a He–Ne 10 mW 632.8 nm laser.
Transmission electron microscopy (TEM) images were obtained
using JEOL JEM-2100F. Scanning electron microscopy (SEM)
images were obtained using JEOL JSM-6700F. Atomic force
microscopy (AFM) observations were performed using Agilent
Technologies Pico-Scan2500 in conventional tapping mode under
air. Fluorescence microscopy images were obtained using a
Keyence BZ-8000 with a ¥60 oil immersion objective lens. Confo-
cal laser scanning microscopy (CLSM) images were obtained using
a Nikon A1R with a ¥100 oil immersion objective lens. Millipore
water was obtained from a Millipore Milli-Q Academic A10
purification unit. Pd2(dba)3·CHCl3,12 1,3-benzenedicarboxylic
acid-2-hydroxy-4,6-dimethyl-1,3-dimethyl ester (10)13 and [2-[2-
(2-methoxyethoxy)ethoxy]ethoxy] p-toluenesulfonate14 were pre-
pared by literature methods. A theoretical calculation was carried
out using the Gaussian 03 program15 with RHF method. The
geometry of the pincer complexes 4 and 5 were optimized by using
a STO-3G basis set.
Table 1 Miyaura–Michael Reaction of 2-Cyclohexene-1-one (24) with
Sodium Tetraphenyl borate (25)
entry
catalyst
conv.,%a
yield,%a
selectivity,%a
1
2
3
4
4vscl
4
5vscl
5
19
21
85
23
19
5
83
7
>99
24
98
30
a Determined by 1H NMR analysis using an internal standard
(Cl2CHCHCl2).
observed by the self-assembling of 4. The reaction of 24 with 25
proceeded in the presence of vesicle 5vscl to provide 26 in 83% yield
with 98% reaction selectivity (entry 3). In contrast, only a 7%
yield of the arylated product 26 was obtained when monomer 5
was used as the catalyst (entry 4). Significant acceleration of the
Miyaura–Michael reaction in water was observed by the formation
of vesicles. Therefore, the construction of self-assembled vesicles is
required for the efficient catalysis of the Miyaura–Michael reaction
in water. In addition, the catalytic activity of the vesicle 5vscl bearing
hydrophilic tri(ethylene glycol) chains close to the palladium center
is higher than that of the vesicle 4vscl bearing hydrophobic dodecyl
chains close to the palladium center (entries 1 and 3).
Conclusions
Preparations
Two amphiphilic pincer palladium complexes bearing hydropho-
bic or hydrophilic side chains, which self-assembled in aqueous
media to provide bilayer vesicles, were designed and prepared.
The catalytic performances of the obtained vesicles 4vscl and 5vscl
are superior to that of the monomeric complexes 4 and 5 for the
Miyaura–Michael reaction in water. In this reaction, the position
of hydrophilic and hydrophobic groups on the pincer backbone is
critical. Detailed catalytic abilities of the vesicles 4vscl and 5vscl, in
particular in an aqueous reaction medium, are being examined for
various palladium catalyses in our laboratory and will be reported
in due course.
4,6-Dimethyl-2-methoxymethoxyisophthalic
acid
dimethyl
ester (11). Under a nitrogen atmosphere, sodium hydride
(5.0 g, 125 mmol, 60% in oil) was slowly added to a solution of 1,3-
benzenedicarboxylic acid-2-hydroxy-4,6-dimethyl-1,3-dimethyl
ester (10) (20.◦0 g, 83.9 mmol) in anhydrous tetrahydrofuran
◦
(600 mL) at 0 C. After stirring at 0 C for 0.5 h, chloromethyl
methyl ether (12.8 mL, 169 mmol) was added to the resulting
mixture, and then the reaction mixture was allowed to warm to
25 ◦C. The reaction mixture was stirred at 25 ◦C for 3 h, and
quenched with saturated ammonium chloride aqueous solution
(200 mL) at 0 ◦C. The resulting mixture was exctracted with ethyl
acetate (200 mL, 3 times). The combined organic layer was dried
over Na2SO4 and concentrated in vacuo. The crude product was
chromatographed on silica gel (eluent: 10–30% AcOEt/n-hexane)
to give 11◦(17.3 g, 61.3 mmol, 73% yield) as white powder. Mp:
57.5–58.0 C; 1H NMR (CDCl3, 500 MHz) d 6.86 (s, 1H, ArH),
4.99 (s, 2H, -OCH2OCH3), 3.90 (s, 6H, -CO2CH3), 3.47 (s, 3H,
-OCH2OCH3), 2.29 (s, 6H, CH3); 13C NMR (CDCl3, 125 MHz)
d 167.6 (-CO2CH3), 151.9 (ArC attached to OCH2OCH3),
138.2 (ArC attached to CH3), 127.9 (ArC attached to H),
126.5 (ArC attached to CO2CH3), 101.2 (-OCH2OCH3), 57.3
(-OCH2OCH3), 52.0 (-CO2CH3), 19.5 (CH3 attached to Ar); IR
(ATR) 3853, 3734, 3649, 3628, 3432, 2994, 2964, 2929, 2831, 2070,
1908, 1721 (C O), 1685, 1635, 1606, 1561, 1475, 1438, 1391,
1380, 1289, 1257, 1201, 1159, 1110, 1092, 1030, 972, 960, 926,
901, 874, 862, 809, 797, 770, 760, 656, 637, 629, 569 cm-1;
Experimental section
General
When manipulations were performed under a nitrogen atmo-
sphere, nitrogen gas was dried by passage through P2O5. Com-
mercially available chemicals (purchased from Aldrich, TCI,
Kanto, Wako, Nacalai and AlfaAesar) are used without fur-
ther purification unless otherwise noted. NMR spectra were
recorded on a JEOL JNM-A500 spectrometer (500 MHz for 1H,
125 MHz for 13C, 202 MHz for 31P). Chemical shifts are reported
in d (ppm) referenced to an internal tetramethylsilane standard
1
for H NMR. Chemical shifts of 13C NMR are given related to
CDCl3 as an internal standard (d 77.0). The 31P NMR data are
1
reported relative to external 85% H3PO4. H, 13C and 31P NMR
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 8859–8868 | 8863
©

EI-TOF-MS m/z 282 ([M]+), 251 ([M-OMe]+), 206
2,6-Dihydroxymethyl-3,5-bis(2,5,8,11-tetraoxadodecyl)phenyl
methoxymethyl ether (14). Under nitrogen atmosphere,
([M-OMe-MOM]+),
191
([M-OMe-MOM-Me]+),
175
a
([M-2OMe-MOM]+), 148 ([M-2OOMe-MOM]+); Anal.
Calcd for C14H18O6: C, 59.57: H, 6.43%. Found: C, 59.23: H,
6.34%.
lithium aluminum hydride (0.69 g, 18.1 mmol) was added to a
solution of 13 (4.4 g, 7.3 mmol) in anhydrous THF (300 mL)
at 0 ◦C. The reaction mixture was stirred at 25 ◦C for 14 h
and then cooled to 0 ◦C. After carefully quenching with water
(2.8 mL) and 15% NaOH aqueous solution (0.7 mL), the
resulting mixture was filtered through Celite and eluted with
ethyl acetate. The filtrate was dried over Na2SO4. The obtained
solution was concentrated under reduced pressure to give 14
4,6-Bis(bromomethyl)-2-methoxymethoxy
isophthalic acid
dimethyl ester (12). Under a nitrogen atmosphere, a mixture of
11 (7.0 g, 24.8 mmol), N-bromosccinimide (9.7 g, 54.6 mmol)
and AIBN (0.41 g, 2.5 mmol) in anhydrous dichloromethane
(250 mL) was irradiated with a 100 W high pressure Hg lamp
(l = 365 nm, Riko-kagaku Co., Lid., UVL-100HA 300P) at
25 ◦C for 1 h to give a yellow solution. The resulting solution
was washed with water (250 mL, 3 times). The combined organic
layer was dried over Na2SO4 and concentrated in vacuo to
give a yellow solid. The resulting solid was recrystallized from
ethyl acetate (200 mL) to afforded 12 (5.9 g, 13.4 mmol, 54%
1
(3.7 g, 6.7 mmol, 93% yield) as colorless oil. H NMR (CDCl3,
500 MHz) d 7.13 (s, 1H, ArH), 5.24 (s, 2H, -OCH2OCH3), 4.68
(s, 2H, -CH2OH), 4.67 (s, 2H, -CH2OH), 4.66 (s, 4H, ArCH2O-),
3.67–3.62 (m, 23H, -OC2H4- and -OCH2OCH3), 3.57–3.52 (m,
4H, -OC2H4-), 3.36 (s, 6H, -CH2(OC2H4)3OCH3); 13C NMR
(CDCl3, 125 MHz) d 156.7 (ArC attached to OCH2OCH3), 137.6
(ArC attached to CH2(OC2H4)3OCH3), 134.3 (ArC attached to
CH2OH), 127.0 (ArC attached to H), 101.4 (-OCH2OCH3), 72.0
(-CH2(OC2H4)3OCH3), 71.8 (-OC2H4-), 70.47 (-OC2H4-),
◦
1
yield) as white needles. Mp: 141.0–141.5 C; H NMR (CD2Cl2,
500 MHz, ref. 5. 30 ppm for CH2Cl2 in CD2Cl2) d 7.27 (s, 1H,
ArH), 4.96 (s, 2H, -OCH2OCH3), 4.49 (s, 4H, -CH2Br), 3.93 (s,
6H, -CO2CH3), 3.43 (s, 3H, -OCH2OCH3); 13C NMR (CDCl3,
70.42
(-OC2H4-),
70.3
(-OC2H4-),
69.3
(-OC2H4-),
58.9 (-CH2(OC2H4)3OCH3), 57.5 (-OCH2OCH3), 56.4 (-CH2OH)
(One of the CH2 signals of ethylene glycol group might be
overlapped with the other peaks of carbon); IR (ATR) 3484
(O–H), 2917, 1469, 1383, 1351, 1286, 1236, 1200, 1090 (C–O–C),
1017, 889, 630 cm-1; ESI-TOF-MS m/z 573 ([M+Na]+); Anal.
Calcd for C26H46O12·0.67H2O: C, 55.50: H, 8.48%. Found: C,
55.28: H, 8.56%.
125 MHz)
d 166.0 (-CO2CH3), 153.3 (ArC attached to
OCH2OCH3), 138.8 (ArC attached to CH2Br), 129.0 (ArC
attached to H), 127.8 (ArC attached to CO2CH3), 101.6
(-OCH2OCH3), 57.6 (-OCH2OCH3), 52.8 (-CO2CH3), 28.9
(-CH2Br); IR (ATR) 3034, 3011, 2956, 2884, 2832, 1721 (C O),
1602, 1567, 1476, 1452, 1434, 1421, 1389, 1308, 1264, 1212, 1201,
1153, 1116, 1041, 1015, 971, 953, 902, 871, 860, 802, 786, 735,
685, 650, 618, 578 cm-1; ESI-TOF-MS m/z 463 ([M+Na]+); Anal.
Calcd for C14H16Br2O6: C, 38.21: H, 3.66%. Found: C, 38.47: H,
3.69%.
2,6-Diformyl-3,5-bis(2,5,8,11-tetraoxadodecyl)phenyl methoxy-
methyl ether (15). Under a nitrogen atmosphere, oxalyl chloride
(2.8 mL, 32.6 mmol) was added to a solution of anhydrous DMSO
(4.7 ◦mL, 66.2 mmol) in anhydrous◦dichloromethane (100 mL) at
-78 C. After being stirred at -78 C for 5 min, a solution of 14
(3.6 g, 6.5 mmol) in anhydrous dichloromethane (100 mL) was
added, and the reaction mixture was stirred for 30 min at -78 ◦C.
Then, triethylamine (13.5 mL, 97.4 mmol) was added, and allow-
ing the solution to warm 25 ◦C. After being stirred at 25 ◦C for 30
min, the reaction mixture was quenched with water (200 mL). The
resulting mixture was extracted with CH2Cl2 (50 mL, 3 times). The
combined organic layer was dried over Na2SO4 and concentrated
in vacuo. The crude product was chromatographed on silica gel
(eluent: 3% MeOH/AcOEt) to give 15 (3.3 g, 6.0 mmol, 92%
yield) as yellow oil. 1H NMR (CDCl3, 500 MHz) d 10.46 (s, 2H,
CHO), 7.94 (s, 1H, ArH), 5.16 (s, 2H, -OCH2OCH3), 4.96 (s, 4H,
ArCH2O-), 3.74–3.54 (m, 27H, -C2H4O- and -OCH2OCH3), 3.37
(s, 6H, -CH2O(C2H4O)3CH3); 13C NMR (CDCl3, 125 MHz) d
191.0 (-CHO), 164.4 (ArC attached to OCH2OCH3), 148.3 (ArC
attached to CH2(OC2H4)3OCH3), 125.9 (ArC attached to CHO),
122.2 (ArC attached to H), 103.4 (-OCH2OCH3), 71.9 (CH2O at-
tached to Ar), 70.7 (-OC2H4-), 70.62 (-OC2H4-), 70.58 (-OC2H4-),
70.47 (-OC2H4-), 70.43 (-OC2H4-), 58.9 (-CH2(OC2H4)3OCH3),
58.3 (-OCH2OCH3), (One of the CH2 signals of ethylene glycol
group might be overlapped with the other peaks of carbon); IR
(ATR) 2873, 1730, 1683 (C O), 1595, 1555, 1457, 1370, 1350,
1287, 1248, 1224, 1201, 1095 (O–C–O), 1029, 981, 898, 850, 794,
665 cm-1; ESI-TOF-MS m/z 569 ([M+Na]+); Anal. Calcd for
C26H42O12·1.5H2O: C, 54.44: H, 7.91%. Found: C, 54.32: H, 7.55%.
2 - Methoxymethoxy - 4,6 - bis(2,5,8,11 - tetraoxadodecyl)isoph-
thalic acid dimethyl ester (13). Under a nitrogen atmosphere,
sodium hydride (0.87 g, 21.6 mmol, 60% in oil) was added
to a solution of triehyleneglycohol monomethyl ether (3.5 g,
21.6 mmol) in anhydrous THF (108 mL). After being stirred
at 0 ◦C for 30 min, 12 (4.8 g, 10.8 mmol) was slowly added.
◦
The reaction mixture was stirred at 0 C for 3 h, and quenched
with water (5 mL). The resulting mixture was extracted with
ethyl acetate (50 mL, 3 times). The combined organic layer was
dried over Na2SO4 and concentrated under reduced pressure. The
crude product was chromatographed on silica gel (eluent: 0–10%
MeOH/AcOEt) to give 13 (4.4 g, 7.2 mmol, 67% yield) as colorless
1
oil. H NMR (CD2Cl2, 500 MHz, ref. 5. 30 ppm for CH2Cl2 in
CD2Cl2) d 7.25 (s, 1H, ArH), 4.95 (s, 2H, -OCH2OCH3), 4.55
(s, 4H, ArCH2O-), 3.85 (s, 6H, -CO2CH3), 3.58–3.53 (m, 20H, -
OC2H4-), 3.48–3.46 (m, 4H, -OC2H4-), 3.42 (s, 3H, -OCH2OCH3),
3.31 (s, 6H, -CH2(OC2H4)3OCH3); 13C NMR (CDCl3, 125 MHz)
d 166.8 (-CO2CH3), 152.5 (ArC attached to OCH2OCH3), 139.4
(ArC attached to CH2(OC2H4)3OCH3), 127.2 (ArC attached to
H), 123.6 (ArC attached to CO2CH3), 101.5 (-OCH2OCH3), 71.8
(CH2 attached to Ar), 70.7 (-OC2H4-), 70.54 (-OC2H4-), 70.52 (-
OC2H4-), 70.44 (-OC2H4-), 70.35 (-OC2H4-), 69.8 (-OC2H4-), 58.9
(-CH2(OC2H4)3OCH3), 57.4 (-OCH2OCH3), 52.3 (-CO2CH3); IR
(ATR) 3007, 2873, 1731 (C O), 1607, 1569, 1541, 1507, 1456,
1430, 1351, 1298, 1246, 1199, 1099 (C–O–C), 1030, 988, 951, 914,
854, 808, 748, 666 cm-1; ESI-TOF-MS m/z 629 ([M+Na]+); Anal.
Calcd for C28H46O14·0.5H2O: C, 54.62: H, 7.69%. Found: C, 54.59:
H, 7.61%.
2,6-Diformyl-3,5-bis(2,5,8,11-tetraoxadodecyl)phenol
(16).
Under a nitrogen atmosphere, a solution of hydrogen chloride
8864 | Dalton Trans., 2011, 40, 8859–8868
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The Royal Society of Chemistry 2011
©

in methanol (10% HCl, 3 mL) was added to a solution of 15
for CH2Cl2 in CD2Cl2) d 10.96 (s, 2H, CHO), 7.46–7.49 (m, 12H,
o-PhH of PPh3), 7.35 (t, 6H, J = 7.3 Hz, p-PhH of PPh3), 7.26
(t, 12H, J = 7.3 Hz, m-PhH of PPh3), 7.07 (s, 1H, ArH), 4.30 (s,
4H, ArCH2O-), 3.59–3.55 (m, 16H, -OC2H4-), 3.50–3.46 (m, 8H,
-OC2H4-), 3.30 (s, 6H, -OCH3); 13C NMR (CDCl3, 125 MHz) d
195.8 (CHO), 181.4 (ArC attached to Pd), 146.5 (ArC attached
to CH2(OC2H4)3OCH3), 136.2 (ArC attached to CHO), 134.1
(virtual t, J = 6.2 Hz, m-PhC of PPh3), 130.3 (p-PhC of PPh3),
129.7 (virtual t, J = 23.6 Hz, ipso-PhC of PPh3), 128.1 (virtual
t, J = 5.2 Hz, o-PhC of PPh3), 122.0 (ArC attached to H), 71.9
(-CH2(OC2H4)3OCH3), 71.0 (-C2H4O-), 70.6 (-C2H4O-), 70.5
(-C2H4O-), 70.4 (-C2H4O-), 70.2 (-C2H4O-), 58.9 (OCH3), (One
of the CH2 signals of ethylene glycol group might be overlapped
with the other peaks of carbon); 31P NMR (CDCl3, 202 MHz)
d 22.2; IR (ATR) 3055, 2872, 2706, 1969, 1828, 1675 (C O),
1570, 1534, 1481, 1435, 1378, 1345, 1273, 1248, 1195, 1093
(O–C–O), 1028, 998, 940, 883, 849, 791, 745, 721, 692, 636, 618
cm-1; ESI-TOF-MS m/z 1175 ([M+Na]+), 1115 ([M-Cl]+), 913
([M-PPh3+Na]+), 853 [M-Cl-PPh3]+), 651 ([M-2PPh3+Na]+),
591 ([M-Cl-2PPh3]+); Anal. Calcd for C60H67ClO10P2Pd: C,
62.56: H, 5.86%. Found: C, 62.33: H, 5.87%.
(3.3 g, 6.0 mmol) in methanol (10 mL) at 25 ◦C. After being
◦
stirred at 25 C for 2 h, the solvent was removed under reduced
pressure to give 16 (3.0 g, 6.0 mmol, 99% yield) as yellow oil. 1H
NMR (CDCl3, 500 MHz) d 12.82 (s, 1H, -OH), 10.52 (s, 2H,
-CHO), 7.37 (s, 1H, ArH), 4.91 (s, 4H, ArCH2O-), 3.73–3.64
(m, 20H, -C2H4O-), 3.56–3.54 (m, 4H, -C2H4O-), 3.37 (s, 6H,
-OCH3); 13C NMR (CDCl3, 125 MHz) 193.4 (-CHO), 166.8 (ArC
attached to OH), 149.5 (ArC attached to CH2(OC2H4)3OCH3),
119.0 (ArC attached to CHO), 118.6 (ArC attached to H), 71.9
(-CH2O-), 71.0 (-C2H4O-), 70.67 (-C2H4O-), 70.63 (-C2H4O-),
70.55 (-C2H4O-), 70.47 (-C2H4O-), 70.3 (-C2H4O-), 59.0 (-OCH3);
IR (ATR) 2872, 1682 (CHO), 1641, 1619, 1558, 1489, 1455, 1415,
1387, 1349, 1321, 1288, 1228, 1200, 1098 (O–C–O), 1031, 941,
889, 850, 804, 718, 671, 638, 598 cm-1; ESI-TOF-MS m/z 525
([M+Na]+); Anal. Calcd for C24H38O11·H2O: C, 55.37: H, 7.74%.
Found: C, 55.53: H, 7.47%.
2,6-Diformyl-3,5-bis(2,5,8,11-tetraoxadodecyl)phenyl trifluoro-
methanesulfonate (17). Undrer a nitrogen atmosphere, to a
solution of 16 (60 mg, 0.12 mmol) in pyridine (1 mL) and
dichloromethane (2 mL) was added trifluoromethanesulfonic
anhydride (0.20 mL, 1.2 mmol) dropwise at -10 ◦C for 3 min.
After being stirred for 1 h at -10 ◦C, the reaction mixture was
quenched with 10% hydrochloric acid (1 mL) and the resulting
mixture was extracted with dichloromethane (5 mL, 3 times). The
combined organic layer was dried over Na2SO4 and concentrated
under reduced pressure. The crude product was chromatographed
on silica gel (eluent: 0–3% MeOH/AcOEt) to give 17 (41 mg,
0.050 mmol, 41% yield) as colorless oil. 1H NMR (CDCl3,
500 MHz) d 10.39 (s, 2H, CHO), 8.20 (s, 1H, ArH), 4.98 (s,
4H, ArCH2O-), 3.76–3.64 (m, 20H, -OC2H4-), 3.55–3.53 (m, 4H,
-OC2H4-), 3.37 (s, 6H, -OCH3); 13C NMR (CDCl3, 125 MHz)
d 187.4 (CHO), 150.4 (ArC attached to OTf), 148.6 (ArC
attached to CH2(OC2H4)3OCH3), 126.8 (ArC attached to CHO),
125.8 (ArC attached to H), 118.5 (q, JC–F = 320 Hz, SO2CF3),
71.9 (-CH2(OC2H4)3OCH3), 70.68 (-C2H4O-), 70.62 (-C2H4O-),
70.60 (-C2H4O-), 70.53 (-C2H4O-), 70.46 (-C2H4O-),
70.43 (-C2H4O-), 59.0 (OCH3); IR (ATR) 2874, 1698 (C O),
1607, 1547, 1467, 1431, 1404, 1371, 1350 (S O), 1294, 1209
(CF3), 1101 (S O), 1028, 994, 950, 906, 880, 850, 808, 763, 643,
602, 577 cm-1; ESI-TOF-MS m/z 657 ([M+Na]+); Anal. Calcd
for C25H37F3O13S·0.5H2O: C, 46.65: H, 5.95%. Found: C, 46.76:
H, 5.89%.
3,5-Dibromo-(tetrahydro-2H-pyran-2-yloxy)benzene (19). p-
Toluenesulfonic acid (240 mg, 1.3 mmol) was added to a solution
of 3,5-dibromobenzene (18) (10.4 g, 41.3 mmol) and 3,4-dihydro-
(2H)-pyran (18.7 mL, 206 mmol) in anhydrous dichloromethane
(100 mL) at 0 ◦C. The solution was stirred for 3 h at 0 ◦C
and subsequently for 30 min at 25 ◦C. The reaction mixture
was poured into saturated aqueous sodium bicarbonate (50 mL).
The organic layer was separated, washed with saturated aqueous
sodium bicarbonate (50 mL, 2 times), water (50 mL) and brine
(50 mL), and then dried over MgSO4. After removal of the solvent,
the resulting mixture was silica gel (eluent: 5% AcOEt/n-hexane)
1
to give (33.1 mmol, 80%). H NMR (500 MHz, CDCl3) d 7.27
(t, J = 1.8 Hz, 1H, ArH), 7.16 (d, J = 1.8 Hz, 2H, ArH), 5.38 (t,
J = 3.0 Hz, 1H, -OCHO-), 3.82 (td, J = 3.0, 10.9 Hz, 1H, CH2),
3.60–3.64 (m, 1H, CH2), 1.91–1.97 (m, 1H, CH2), 1.82–1.85 (m,
2H, CH2), 1.57–1.74 (m, 2H, CH2); 13C NMR (125 MHz, CDCl3)
d 158.2 (ArC attached to O), 127.1 (ArC), 122.8 (ArC attached
to Br), 118.7 (ArC), 96.5 (CH), 61.9 (CH2 attached to O), 30.0
(CH2), 24.9 (CH2), 18.3 (CH2); IR (ATR) 2942, 1582, 1556, 1433,
1420, 1389, 1373, 1355, 1292, 1248 (C–O–C), 1228 (C–O–C), 1200
(C–O–C), 1183, 1118 (C–O–C), 1104 (C–O–C), 1073, 1050, 1036
(C–O–C), 1021 (C–O–C), 988, 955, 921, 893, 872, 833, 817, 744,
692, 668, 629, 571 cm-1; FAB-MS m/z 336 ([M]+); Anal. Calcd for
C11H12Br2O2: C, 39.32: H, 3.60%. Found: C, 39.20: H, 3.62%.
trans-[2,6-Diformyl-3,5-bis(2,5,8,11-tetraoxadodecyl)phenyl]-
chloro bis(triphenylphosphine)palladium (6). 17 (0.18 g,
0.29 mmol), Pd2(dba)3·CHCl3 (0.15 g, 0.15 mmol) and
triphenylphosphine (0.15 g, 0.58 mmol) were dissolved in 2 mL
of anhydrous dichloromethane◦under a nitrogen atmosphere, and
the solution was stirred at 25 C for 20 h. After removal of the
solvent, the residue and lithium chloride (0.12 g, 2.9 mmol) were
dissolved in a mixture of acetone (1.8 mL) and water (0.2 mL).
The reaction mixture was stirred at 25 ◦C for 20 h and then
concentrated under reduced pressure. The residue was dissolved
in chloroform (10 mL), which was washed with water (5 mL,
2 times), dried over Na2SO4 and concentrated under reduced
pressure. The crude product was chromatographed on silica gel
(eluent: 0–5% MeOH/AcOEt) to give 10 (0.30 g, 0.26 mmol, 89%
yield) as yellow oil. 1H NMR (CD2Cl2, 500 MHz, ref. 5. 30 ppm
3,5-Didodecyl(tetrahydro-2H-pyran-2-yloxy)benzene
To a solution of 19 (6.0 g, 17.8 mmol) and dichloro[1,1¢-
bis(diphenylphosphino)ferrocene]palladium(II) (726 mg,
(20).
0.90 mmol) in 40 mL of anhydrous THF was added
dodecylmagnesium bromide (2 M in diethyl ether, 36 mL,
72 mmol) under a nitrogen atmosphere. The reaction mixture
was refluxed at 75 ◦C for 72 h and then cooled to 25 ◦C. After
quenching with a small amount of methanol, the resulting
mixture was filtrated through Celite and eluted with n-hexane
and tert-butyl methyl ether. Upon removal of the solvent, the
resulting mixture was chromatographed on silica gel (eluent:
1–5% AcOEt/n-hexane) to give 20 (6.51 g, 12.6 mmol, 71%) as
colorless oil. 1H NMR (500 MHz, CDCl3) d 6.69 (br s, 2H, ArH),
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 8859–8868 | 8865
©

6.62 (br s, 1H, ArH), 5.40 (t, J = 3.0 Hz, 1H, -OCHO-), 3.91–3.96
(m, 1H, CH2), 3.58–3.62 (m, 1H, CH2), 2.53 (t, J = 7.9 Hz,
4H, -CH2(CH2)10CH3), 1.96–2.03 (m, 1H, CH2), 1.82–1.87 (m,
2H, CH2), 1.62–1.71 (m, 2H, CH2), 1.55–1.59 (m, 4H, CH2),
1.25–1.29 (m, 36H, -CH2(CH2)10CH3), 0.88 (t, J = 7.0 Hz, 6H,
-CH2(CH2)10CH3); 13C NMR (125 MHz, CDCl3) d 157.0 (ArC
attached to O), 144.1 (ArC attached to C12H25), 122.0 (ArC),
113.7 (ArC), 96.3 (CH), 62.0 (CH2 attached to O), 36.0 (CH2
attached to Ar), 31.9 (CH2), 31.4 (CH2), 30.5 (CH2), 29.68
(CH2), 29.66 (CH2), 29.62 (CH2), 29.5 (CH2), 29.4 (CH2), 29.3
(CH2), 25.3 (CH2), 22.7 (CH2), 18.8 (CH2), 14.1 (CH3) (One
of the CH2 signals of dodecyl group might be overlapped with
the other peaks of carbon.); IR (ATR) 2921, 2852, 1455, 1284,
1202 (C–O–C), 1152, 1125 (C–O–C), 1106 (C–O–C), 1078, 1038
(C–O–C), 1021 (C–O–C), 990, 954, 906, 871, 855, 720, 700 cm-1;
FAB-MS m/z 514 ([M]+); Anal. Calcd for C35H62O2: C, 81.65: H,
12.14%. Found: C, 81.46: H, 12.15%.
22.6 (CH2), 14.0 (CH3) (Two of the CH2 carbons of dodecyl group
might be overlapped with the other peaks of carbon.); IR (ATR)
2921, 2852, 1687 (CHO), 1638 (CHO), 1615, 1552, 1487, 1465,
1420, 1385, 1348, 1296, 1233, 1179, 1115, 1085 cm-1; FAB-MS
m/z 487 ([M+1]+); Anal. Calcd for C32H54O3: C, 78.96: H, 11.18%.
Found: C, 78.62: H, 11.18%.
3,5-Didodecyl-2,6-diformylphenyl
trifluoromethanesulfonate
(23). To a solution of 22 (105 mg, 0.215 mmol) in pyridine
(2 mL) and anhydrous dichloromethane (2 mL) under a nitrogen
atmosphere was added trifluoromethanesulfonic anhydride
(0.36 mL, 2.15 mmol) dropwise at -10 ◦C for 3 min, and the
resulting mixture was stirred for 1.5 h at -10 to 0 ◦C. The reaction
mixture was quenched with 1.5 N HCl (10 mL) and extracted
with dichloromethane (20 mL, 3 times). The combined organic
layer was dried over Na2SO4. After removal of the solvent, the
resulting mixture was chromatographed on silica gel (eluent:
30–50% CHCl3/n-hexane) to give 23 (56.8 mg, 0.092 mmol,
1
3,5-Didodecylphenol (21). p-Toluenesulfonic acid (190 mg,
1.0 mmol) was added to a solution of 20 (10.59 g, 20.6 mmol)
in THF (20 mL) and methanol (20 mL) at 25 ◦C and the reaction
mixture was stirred for 1 h at 25 ◦C, quenched with water and
extracted with tert-butyl methyl ether (20 mL, 3 times). The
organic layer was washed with water (20 mL) and brine (20 mL),
and dried over Na2SO4. The organic layer was concentrated under
reduced pressure to give 21 (8.84 g, 20.5 mmol, 99%) as colorless
43%) as pale yellow oil. H NMR (500 MHz, CDCl3) d 10.39
(s, 2H, CHO), 7.22 (s, 1H, ArH), 3.00 (t, J = 7.6 Hz, 4H,
-CH2(CH2)10CH3), 1.55–1.61 (m, 4H, CH2), 1.26–1.38 (m, 36H,
-CH2(CH2)10CH3), 0.88 (t, J = 6.7 Hz, 6H, -CH2(CH2)10CH3); 13
C
NMR (125 MHz, CDCl3) d 187.4 (CHO), 152.4 (ArC attached
to C12H25), 151.6 (ArC attached to CHO), 133.9 (ArC), 125.9
(ArC attached to CHO), 118.5 (q, JC–F = 320.6 Hz, SO2CF3),
33.8 (CH2 attached to Ar), 31.9 (CH2), 31.5 (CH2), 29.68 (CH2),
29.66 (CH2), 29.64 (CH2), 29.61 (CH2), 29.5 (CH2), 29.3 (CH2),
22.7 (CH2), 14.1 (CH3) (One of the CH2 signals of dodecyl group
might be overlapped with the other peaks of carbon.); IR (ATR)
2922, 2853, 1701 (CHO), 1604, 1539, 1465, 1431, 1406, 1375,
1213 (S O), 1134 (S O),1070, 964, 891, 810, 761, 722, 673, 601
cm-1; ESI-MS m/z 619 ([M+1]+); Anal. Calcd for C33H53F3O5S:
C, 64.05: H, 8.63: S, 5.18%. Found: C, 64.09: H, 8.69: S, 5.24%.
◦
1
powder. Mp. 33–34 C; H NMR (500 MHz, CDCl3) d 6.57 (br
s, 1H, ArH), 6.46 (br s, 2H, ArH), 4.48 (br s, 1H, OH), 2.51
(t, J = 7.9 Hz, 4H, -CH2(CH2)10CH3), 1.56–1.59 (m, 4H, CH2),
1.25–1.29 (m, 36H, -CH2(CH2)10CH3), 0.88 (t, J = 7.0 Hz, 6H,
-CH2(CH2)10CH3); 13C NMR (125 MHz, CDCl3) d 155.3 (ArC
attached to O), 144.6 (ArC attached to C12H25), 121.2 (ArC),
112.4 (ArC), 35.8 (CH2 attached to Ar), 31.9 (CH2), 31.3 (CH2),
29.68 (CH2), 29.64 (CH2), 29.60 (CH2), 29.5 (CH2), 29.3 (CH2),
22.6 (CH2), 14.1 (CH3) (Two of the CH2 signals of dodecyl group
might be overlapped with the other peaks of carbon.); IR (ATR)
3271 (O–H), 2952, 2913, 2848, 1595, 1469, 1450, 1305, 1291, 1277,
1254, 1149 (C–O), 1122, 1022, 991, 959, 854, 718, 696, 642 cm-1;
FAB-MS m/z 431 ([M+1]+); Anal. Calcd for C30H54O: C, 83.65:
H, 12.64%. Found: C, 83.43: H, 12.59%.
trans-(3,5-Didodecyl-2,6-diformylphenyl)chlorobis(triphenyl-
phosphine)palladium (7). 22 (747 mg, 1.21 mmol), Pd2(dba)3·
CHCl3 (620 mg, 0.60 mmol), and triphenylphosphine (635
mg, 2.42 mmol) were dissolved in 15 mL of anhydrous
dichloromethane under a nitrogen atmosphere, and the solution
was stirred at 25 ◦C for 39 h. After removal of the solvent, the
residue and lithium chloride (513 mg, 12.1 mmol) were suspended
in a mixture of acetone (13.5 mL) and water (1.5 mL). The
reaction mixture was stirred at room temperature for 24 h and
then extracted with chloroform (30 mL, 3 times). The organic layer
was dried over Na2SO4 and concentrated in vacuo. The residual
material was chromatographed on silica gel (eluent: CHCl3) to give
3,5-Didodecyl-2,6-diformylphenol (22). 21 (4.30 g, 10.0 mmol)
and hexamethylenetetramine (2.80 g, 20 mmol) were dissolved
in anhydrous trifluoroacetic acid (20 mL) under a nitrogen
atmosphere, and the resulting solution was refluxed at 100 ◦C
for 24 h. To the reaction mixture was added 4 N HCl (20 mL) and
the mixture was stirred for 24 h at 100 ◦C. After being cooled to
25 ◦C, the mixture was extracted with CH2Cl2 (30 mL, 3 times). The
combined organic layer was dried over MgSO4, and concentrated
in vacuo. The resulting crude mixture was chromatographed on
silica gel (eluent: 30–50% CHCl3/n-hexane) to give 22 (648 mg,
◦
7 (1292 mg, 1.14 mmol, 94%) as yellow powder. Mp. 76–78 C;
1H NMR (500 MHz, CDCl3) d 10.91 (s, 2H, CHO), 7.47–7.51 (m,
12H, o-PhH of PPh3), 7.32 (t, J = 7.3 Hz, 6H, p-PhH of PPh3),
7.23 (t, J = 7.3 Hz, 12H, m-PhH of PPh3), 6.21 (s, 1H, ArH),
2.33 (t, J = 7.9 Hz, 4H, -CH2(CH2)10CH3), 1.23–1.31 (m, 36H,
-CH2(CH2)10CH3), 1.11 (br s, 4H, CH2), 0.88 (t, J = 7.0 Hz, 6H,
-CH2(CH2)10CH3); 13C NMR (125 MHz, CDCl3) d 195.0 (CHO),
180.3 (t, JC–P = 4.1 Hz, ArC attached to Pd), 150.6 (ArC), 136.9
(ArC attached to CHO), 135.0 (t, JC–P = 6.2 Hz, p-PhC of PPh3),
134.3 (t, JC–P = 6.2 Hz, m-PhC of PPh3), 130.14 (t, JC–P = 22.8 Hz,
ipso-PhC of PPh3), 130.12 (ArC attached to C12H25), 128.0 (virtual
t, JC–P = 5.2 Hz, o-PhC of PPh3), 33.7 (CH2 attached to Ar), 31.9
(CH2), 31.6 (CH2), 29.9 (CH2), 29.69 (CH2), 29.67 (CH2), 29.65
(CH2), 29.4 (CH2), 29.3 (CH2), 22.7 (CH2), 14.1 (CH3) (One of
◦
1
1.3 mmol, 13%) as yellow powder. Mp. 30.5–31.0 C; H NMR
(500 MHz, CDCl3) d 12.82 (s, 1H, -OH), 10.43 (br s, 2H, -CHO),
6.60 (s, 1H, ArH), 2.93 (t, J = 7.9 Hz, 4H, -CH2(CH2)10CH3),
1.56–1.62 (m, 4H, CH2), 1.25–1.39 (m, 36H, -CH2(CH2)10CH3),
0.88 (t, J = 6.7 Hz, 6H, -CH2(CH2)10CH3); 13C NMR (125 MHz,
CDCl3) d 192.2 (br, CHO), 167.6 (br, ArC attached to C12H25),
154.6 (ArC attached to O), 124.0 (ArC), 118.4 (br, ArC attached
to CHO), 33.3 (CH2 attached to Ar), 31.89 (CH2), 31.84 (CH2),
29.68 (CH2), 29.63 (CH2), 29.61 (CH2), 29.39 (CH2), 29.32 (CH2),
8866 | Dalton Trans., 2011, 40, 8859–8868
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The Royal Society of Chemistry 2011
©

the CH2 signals of dodecyl group might be overlapped with the
other peaks of carbon.); 31P NMR (202 MHz, CDCl3) d 22.0; IR
(ATR) 2922, 2851, 1681 (CHO), 1567, 1519, 1481, 1465, 1434,
1414, 1186, 1094, 1072, 998, 742, 721, 692 cm-1; ESI-TOF-MS
m/z 1099 ([M-Cl]+); Anal. Calcd for C68H83ClO2P2Pd: C, 71.88:
H, 7.36%. Found: C, 71.64: H, 7.35%.
1504, 1465, 1420, 1345, 1308, 1290, 1253, 1201, 1189, 1092 (O–
C–O), 1034, 980, 940, 885, 860, 835, 767, 723, 676, 632, 616, 559
cm-1; MALDI-TOF-MS Calcd. for C60H95N2O8Pd ([M-Cl]+):
m/z = 1077.61, found 1077.67; Anal. Calcd for C60H95ClN2O8Pd:
C, 64.67: H, 8.59: N, 2.51%. Found: C, 64,79: H, 8.54: N, 2.57%.
[3,5-Didodecyl-2,6-bis{N -4-(2,5,8,11-tetraoxadodecyl)phenyl-
imino}phenyl]chloropalladium (5). Under a nitrogen atmosphere,
7 (280 mg, 0.25 mmol) and 9 (730 mg, 2.5 mmol) were dissolved
in anhydrous MeCN (5 mL). The solution was refluxed under a
nitrogen atmosphere for 86 h to give a yellow solution. After the
solution was cooled to 25 ◦C, urea hydrogen peroxide (46 mg,
0.50 mmol) was added and the resulting mixture was stirred
at 50 ◦C for 24 h. After removal of the solvent, the residue
was chromatographed on silica gel (eluent: 1–2% MeOH/CHCl3)
followed by gel permeation chromatography (eluent: CHCl3) to
afford the pincer complex 5 (208.6 mg, 0.187 mmol, 76%) as yellow
4-(2,5,8,11-tetraoxadodecyl)aniline (9). 4-Aminobenzylal-
cohol (2.0 g, 16.2 mmol) and sodium hydride (972 mg, 60%
in oil, 24.3 mmol) were suspended in anhydrous THF (30 mL)
under a nitrogen atmosphere. After the suspension was stirred
at 25 ◦C for 1.5 h, a anhydrous THF solution (5 mL) of
[2-[2-(2-methoxyethoxy)ethoxy]ethoxy] p-toluenesulfonate (6.2 g,
19.5 mmol) was added at 25 ◦C, and the resulting mixture was
refluxed for 24 h. After the mixture was cooled to 25 ◦C, a small
amount of water was added to the reaction mixture, which was
extracted with dichloromethane (30 mL, 3 times). The combined
organic layer was dried over MgSO4 and concentrated in vacuo.
The resulting residue was chromatographed on silica gel (eluent:
70–90% AcOEt/n-hexane) to give 9 (2.34 g, 8.74 mmol, 54%)
1
oil. H NMR (500 MHz, CDCl3) d 8.23 (s, 2H, CH N), 7.47
(d, J = 7.9 Hz, 4H, ArH), 7.36 (d, J = 8.5 Hz, 4H, ArH), 6.72
(s, 1H, ArH), 4.57 (s, 4H, -OCH2C6H4N ), 3.63–3.69 (m, 20H,
-O(C2H4O)3CH3), 3.54–3.56 (m, 4H, -O(C2H4O)3CH3), 3.37 (s,
6H, -O(C2H4O)3CH3), 2.76 (t, J = 7.6 Hz, 4H, -CH2(CH2)10CH3),
1.61–1.66 (m, 4H, CH2), 1.25–1.38 (m, 36H, -CH2(CH2)10CH3),
0.87 (t, J = 6.7 Hz, 6H, -CH2(CH2)10CH3); 13C NMR (125 MHz,
CDCl3) d 187.5 (ArC attached to Pd), 171.9 (CH N), 148.4
(ArC), 146.3 (ArC), 139.8 (ArC), 138.3 (ArC), 127.8 (ArC),
125.6 (ArC), 123.7 (ArC), 72.7 (CH2 attached to C6H4), 71.9
(OC2H4O), 70.6 (OC2H4O), 70.5 (OC2H4O), 70.3 (OC2H4O), 69.5
(OC2H4O), 59.0 (OCH3), 34.1 (CH2 attached to Ar), 31.9 (CH2),
31.7 (CH2), 29.66 (CH2), 29.63 (CH2), 29.5 (CH2), 29.4 (CH2),
29.39 (CH2), 29.34 (CH2), 22.6 (CH2), 14.1 (CH3) (One of the
CH2 signals of dodecyl group and one of the CH2 signals of
triethyleneglycol group might be overlapped with the other peaks
of carbon.); IR (ATR) 2921, 2852, 1574, 1526, 1505, 1464, 1348,
1199, 1097 (C–O), 1017, 943, 827 cm-1; MALDI-TOF-MS Calcd.
for C60H95N2O8Pd [M-Cl]+: m/z = 1077.61; Found 1077.62; Anal.
Calcd for C60H95ClN2O8Pd: C, 64.67: H, 8.59: N, 2.51%. Found:
C, 64.45: H, 8.52: N, 2.61%.
1
as pale yellow oil. H NMR (500 MHz, CDCl3) d 7.13 (d, J =
8.54 Hz, 2H, ArH), 6.65 (d, J = 8.54 Hz, 2H, ArH), 4.43 (s, 2H,
-CH2O(C2H4O)3CH3), 3.37–3.69 (m, 12H, -CH2O(C2H4O)3CH3),
3.37 (s, 3H, -CH2O(C2H4O)3CH3); 13C NMR (125 MHz, CDCl3)
d 146.0 (ArC attached to CH2), 129.4 (ArC), 128.0 (ArC attached
to NH2), 114.8 (ArC), 73.1 (CH2 attached to C6H4), 71.9
(OC2H4O), 70.65 (OC2H4O), 70.60 (OC2H4O), 70.55 (OC2H4O),
70.50 (OC2H4O), 68.8 (OC2H4O), 59.0 (OCH3); IR (ATR) 3445
(NH2), 3358 (NH2), 3235, 2867, 1777, 1626, 1613, 1518, 1453, 1348,
1286, 1249, 1175, 1085 (C–O), 1024, 941, 822, 559 cm-1; ESI-TOF-
MS m/z 292 ([M+Na]+); Anal. Calcd for C14H23NO4·0.25H2O: C,
61.40: H, 8.65: N, 5.11%. Found: C, 61.10: H 8.54: N, 4.99%.
[3,5c-Bis(2,5,8,11-tetraoxadodecyl)-2,6-bis(N-4-dodecylphenyl-
imino)phenyl]chloropalladium (4). Under a nitrogen atmosphere,
6 (0.40 g, 0.35 mmol) and 4-dodecyl aniline (8) (0.90 g, 3.5 mmol)
were dissolved in anhydrous MeCN (4 mL). The solution was
refluxed under a nitrogen atmosphere for 72 h to give a yellow
solution. After the solution cooled to 25 ◦C, urea hydrogen
peroxide (68 mg, 0.72 mmol) was added and the reaction mixture
was stirred at 50 ◦C for 11 h. After removal of the solvent,
the residue was chromatographed on silicagel (eluent: 0–5%
MeOH/AcOEt) followed by gel permeation chromatography
(eluent: CHCl3) to afford the pincer complex 4 (0.33 g, 0.29 mmol,
85% yield) as yellow solids. Mp. 56.5–57.0 ◦C; 1H NMR (CDCl3,
500 MHz) d 8.57 (s, 2H, CH N), 7.45 (d, 4H, J = 8.5 Hz, ArH),
7.17 (d, 4H, J = 8.0 Hz, ArH), 6.93 (s, 1H, ArH), 4.71 (s, 4H,
ArCH2O-), 3.67 (s, 8H, -OC2H4-), 3.60–3.49 (m, 16H, -OC2H4-),
3.35 (s, 6H, -OCH3), 2.60 (t, 4H, J = 7.0 Hz, CH2C10H20CH3),
1.62–1.57 (m, 4H, CH2), 1.31–1.26 (m, 36H, CH2C10H20CH3),
0.88 (t, 6H, J = 7.0 Hz, -CH2(CH2)10CH3); 13C NMR (CDCl3,
125 MHz) d 187.4 (ArC attached to Pd), 172.7 (HC N), 146.8
(ArC), 143.0 (ArC attached to HC N), 141.3 (ArC attached
to CH2(OC2H4)3OCH3), 139.8 (ArC), 128.3 (ArC), 123.6 (ArC),
123.1 (ArC attached to H), 71.8 (CH2O attached to Ar), 71.5
(-C2H4O-), 70.50 (-C2H4O-), 70.49 (-C2H4O-), 70.46 (-C2H4O-),
70.44 (-C2H4O-), 69.8 (-C2H4O-), 59.0 (OCH3), 35.6 (CH2 attached
to Ar), 31.9 (CH2), 31.3 (CH2), 29.65 (CH2), 29.63 (CH2), 29.60
(CH2), 29.57 (CH2), 29.48 (CH2), 29.40 (CH2), 29.31 (CH2), 22.6
(CH2), 14.1 (CH3); IR (ATR) 2922, 2852, 1599 1579 (C N), 1531,
Formation of vesicles
4vscl: Ten mg of 4 was placed in a 30 mL sample tube and dissolved
with 1 mL of CH3CN to give a pale yellow solution. Then, 9 mL
of Millipore water was added to the solution, which was slowly
◦
concentrated at 80 C for 6 h without stirring to generate a pale
yellow suspension of 4vscl . The obtaining yellow suspension of 4vscl
was centrifuged (4000 rpm, 15 min) to give a precipitate and a
supernatant. The supernatant was removed by decantation to af-
ford the vesicle 4vscl . The resulting aqueous suspension was diluted
with 1 mL of Millipore water. The suspension was characterized
by DLS (vide infra) and microscopic analyses (vide infra).
5
vscl: A chloroform solution of 5 (0.1 mL, 10 mg mL-1) was
charged in a 4 mL vial. After evaporation of the chloroform, a
thin film of 5 was formed on the inner glass surface of the vial.
Then, 2 mL of Millipore water was added to the vial followed by
heating the resulting mixture at 60 ◦C for 4 h without stirring.
After standing at 25 ◦C for overnight, the sample was vortexed for
5 min to generate a pale yellow suspension of 5vscl. The suspension
was characterized by DLS (vide infra) and microscopic analyses
(vide infra).
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 8859–8868 | 8867
©

Dynamic light scattering (DLS) analysis
Acknowledgements
The vesicle suspensions of 4vscl and 5vscl were placed in a glass tube.
The DLS measurement was performed with 200 times repetition
of signal scans. Particle sizes are estimated using the Cumulant
method of data analysis.
We acknowledge the JSPS (Grant-in-Aid for Scientific Research
No. 20655035; Grant-in-Aid for Scientific Research on Innovative
Area No. 2105) for partial financial support of this work. We
also thank Dr R. Tero (Toyohashi University of Technology,
Japan) for AFM measurements. Confocal images were acquired at
the Spectrography and Bioimaging Facility, NIBB Core Research
Facilities.
Transmission electron microscopy (TEM) analysis
Samples for TEM analysis were prepared by the following method:
suspensions of the vesicle 4vscl and 5vscl were dropped onto a copper
grid covered with a carbon membrane and then air-dried. The
obtained samples were measured by TEM.
Notes and references
1 For a recent review, see: N. Selander and K. J. Szabo´, Chem. Rev., 2011,
111, 2048; and references therein.
2 S. K. Yang, A. V. Ambade and M. Weck, Chem. Soc. Rev., 2011, 40,
129.
Scanning electron microscopy (SEM) analysis
Samples for SEM analysis were prepared by the following method:
a suspension of the vesicle 4vscl and 5vscl were dropped onto a
silicon wafer (Nilaco, P, Low, <0.02 Xcm) and then air-dried.
The obtained samples were measured by SEM.
3 K. Takenaka, M. Minakawa and Y. Uozumi, J. Am. Chem. Soc., 2005,
127, 12273.
4 (a) T. Kimura and Y. Uozumi, Organometallics, 2006, 25, 4883; (b) T.
Kimura and Y. Uozumi, Organometallics, 2008, 27, 5159.
5 J. W. Steed and J. L. Atwood, Supramolecular Chemistry 2-nd ed, Wiley,
Chichester, 2009.
6 J. P. Hill, W. Jin, A. Kosaka, T. Fukushima, H. Ichihara, T. Shimomura,
K. Ito, T. Hashizume, N. Ishii and T. Aida, Science, 2004, 304,
1481.
7 Preliminary result on the formation of vesicle and its catalytic
application of pincer palladium complex 5, see: G. Hamasaka,
T. Muto and Y. Uozumi, Angew. Chem., Int. Ed., 2011, 50,
4876.
Atomic force microscopy (AFM) analysis
Samples for AFM analysis were prepared by the following method:
a suspension of the vesicle 4vscl and 5vscl were dropped onto freshly
cleaved mica then air-dried. AFM analyses were performed under
air in a conventional tapping mode.
8 Examples for construction of the self-assembled architecture derived
from pincer complexes, see: (a) T. Tu, W. Assenmacher, H. Peterlik,
R. Weisbarth, M. Nieger and K. H. Do¨tz, Angew. Chem., Int. Ed.,
2007, 46, 6368; (b) A. O. Moughton and R. K. O’Reilly, J. Am. Chem.
Soc., 2008, 130, 8714; (c) A. O. Moughton, K. Stubenrauch and R. K.
O’Reilly, Soft Matter, 2009, 5, 2361.
9 For recent reviews on Miyaura–Michael reactions, see: (a) N. Miyaura,
Synlett, 2009, 2039; (b) N. Miyaura, Bull. Chem. Soc. Jpn., 2008, 81,
1535.
10 Recent examples of vesicle formation via self-assemble under thermal
conditions, see: (a) G. P. Robbins, M. Jimbo, J. Swift, M. J. Therien,
D. A. Hammer and I. J. Dmochowski, J. Am. Chem. Soc., 2009,
131, 3872; (b) W. Cai, G.-T. Wang, Y.-X. Xu, X.-K. Jiang and Z.-
T. Li, J. Am. Chem. Soc., 2008, 130, 6936; (c) F. J. M. Hoeben,
I. O. Shklyarevskiy, M. J. Pouderoijen, H. Engelkamp, A. P. H. J.
Schenning, P. C. M. Christianen, J. C. Maan and E. W. Meijer, Angew.
Chem., Int. Ed., 2006, 45, 1232; (d) Y. J. Jeon, P. K. Bharadwaj, S.
W. Choi, J. W. Lee and K. Kim, Angew. Chem., Int. Ed., 2002, 41,
4474.
Fluorescence microscopy and confocal laser scanning microscopy
(CLSM) analyses
Samples for fluorescence microscopy and CLSM were prepared
by the following method: to suspensions of 4vscl and 5vscl in
water (0.1 mg/1 mL) were added 1 mL of an EtOH solution of
fluoresceine (0.45 mM) to give stained 4vscl and 5vscl , respectively.
The stained 4vscl and 5vscl were cast (1 drop) onto slide glasses. The
resulting slide glasses were subjected to fluorescence microscopy
and CLSM.
Miyaura–Michael reaction (general procedure)
To a vial 1 mL aqueous suspension of 4vscl (2.6 mg, 2.4 ¥
10-3 mmol), 2-cyclohexene-1-one (24, 11.5 mg, 0.12 mmol) and
sodium tetraphenylborate (25, 61.6 mg, 0.18 mmol) we◦re added.
The reaction mixture was agitated with shaking at 25 C for 12
h. The reaction mixture was quenched with sodium chloride, and
then extracted with MTBE (1.5 mL x 4 times). The combined
extract was dried over Na2SO4, and then filtered through silica
gel using MTBE as an eluent. After removal of the solvent,
the product was dissolved by a CDCl3 solution of 1,1,2,2-
tetrachloroethane an internal standard. The chemical yield was
determined by 1H NMR measurement.
11 The molecular structures of 4 and 5 were preliminarily simulated by
RHF/STO-3G.
12 K. Ukai, H. Kawazura and Y. Ishii, J. Organomet. Chem., 1974, 65,
253.
13 G. N. Walker, J. Org. Chem., 1958, 23, 34.
14 S. Kohmoto, E. Mori and K. Kishikawa, J. Am. Chem. Soc., 2007, 129,
13364.
15 M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb,
J. R. Cheeseman, J. A. Montgomery Jr., T. Vreven, K. N. Kudin, J. C.
Burant, J. M. Millam, S. S. Iyengar, J. Tomasi, V. Barone, B. Mennucci,
M. Cossi, G. Scalmani, N. Rega, G. A. Petersson, H. Nakatsuji, M.
Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T.
Nakajima, Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li, J. E.
Knox, H. P. Hratchian, J. B. Cross, V. Bakken, C. Adamo, J. Jaramillo,
R. Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi,
C. Pomelli, J. W. Ochterski, P. Y. Ayala, K. Morokuma, G. A. Voth,
P. Salvador, J. J. Dannenberg, V. G. Zakrzewski, S. Dapprich, A. D.
Daniels, M. C. Strain, O. Farkas, D. K. Malick, A. D. Rabuck, K.
Raghavachari, J. B. Foresman, J. V. Ortiz, Q. Cui, A. G. Baboul, S.
Clifford, J. Cioslowski, B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz,
I. Komaromi, R. L. Martin, D. J. Fox, T. Keith, M. A. Al-Laham, C. Y.
Peng, A. Nanayakkara, M. Challacombe, P. M. W. Gill, B. Johnson, W.
Chen, M. W. Wong, C. Gonzalez and J. A. Pople, Gaussian 03, Revision
C.02, Gaussian Inc, Wallingford CT, 2004.
3-Phenylcyclohexanone (26). [CAS: 20795-53-3]. 1H NMR
(500 MHz, CDCl3) d 7.31–7.34 (m, 2H, PhH), 7.21–7.25 (m, 3H,
PhH), 2.98–3.04 (m, 1H, CH attached to Ph), 2.57–2.62 (m, 1H,
CH2), 2.50–2.55 (m, 1H, CH2), 2.43–2.48 (m, 1H, CH2), 2.34–2.41
(m, 1H, CH2), 2.12–2.17 (m, 1H, CH2), 2.06–2.10 (m, 1H, CH2),
1.73–1.89 (m, 2H, CH2); 13C NMR (125 MHz, CDCl3) d 210.9
(C O), 144.3 (PhC attached to cyclohexanone), 128.6 (PhC),
126.6 (PhC), 126.5 (PhC), 48.9 (CH attached to Ph), 44.7 (CH2),
41.1 (CH2), 32.7 (CH2), 25.5 (CH2); MS m/z 174 (M+).
8868 | Dalton Trans., 2011, 40, 8859–8868
This journal is
The Royal Society of Chemistry 2011
©