Regioselective fabrications of a M?bius aromatic [28]hexaphyrin palladium(II) complex

Article abstract of DOI:10.1142/S1088424612501428

Regioselective nucleophilic chlorination and bromination of [26]hexaphyrin to produce a [28]M?bius aromatic hexaphyrin Pd(II) complex were accomplished upon treatment of [26]hexaphyrin 2 with chloride and bromide ions in the presence of an acid with concurrent molecular topology change from Hückel to M?bius. Stille coupling reaction of the resultant 3-brominated complex 4 with ethynylstannanes afforded β-ethynylated derivatives in moderate to high yields.

Full text of DOI:10.1142/S1088424612501428

Journal of Porphyrins and Phthalocyanines
J. Porphyrins Phthalocyanines 2013; 17: 665–672
DOI: 10.1142/S1088424612501428
Published at http://www.worldscinet.com/jpp/
Regioselective fabrications of a Möbius aromatic
[28]hexaphyrin palladium(II) complex
TomokiYonedaa◊◊, Naoki Aratania,b◊ and Atsuhiro Osuka*a◊
a Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
b PRESTO, Japan Science and Technology Agency, Japan
Dedicated to Professor Evgengy Luk’yanets on the occusion of his 75th birthday
Received 2 October 2012
Accepted 5 November 2012
ABSTRACT: Regioselective nucleophilic chlorination and bromination of [26]hexaphyrin to produce a
[28]Möbius aromatic hexaphyrin Pd(II) complex were accomplished upon treatment of [26]hexaphyrin
2 with chloride and bromide ions in the presence of an acid with concurrent molecular topology change
from Hückel to Möbius. Stille coupling reaction of the resultant 3-brominated complex 4 with ethynyl-
stannanes afforded b-ethynylated derivatives in moderate to high yields.
KEYWORDS: Möbius aromaticity, hexaphyrin, regioselective reaction, nucleophilic addition,
palladium complex, palladium migration, topology change.
their effective peripheral fabrications are desired but
such reactions have been only scarcely explored so
far [7]. Considering the C1 symmetric structures of
Möbius aromatic expanded porphyrins, peripheral
fabrications should be rigorously regioselective
for their useful functionalizations. In this context,
the reversible interconversion between Möbius
INTRODUCTION
Möbius aromaticity is one of the current topics in
organic chemistry, which predicts the aromaticity of [4np]
annulenes when lying on a singly twisted Möbius-strip-
like p-conjugation [1]. This concept was first proposed
by Heilbronner in 1964 [2], and was elegantly used to
interpret the electrocyclic reactions by Zimmerman [3].
aromatic [28]hexaphyrin Pd(II) complex 1 and
After some calm, an important paper by Herges et al. in
Hückel aromatic [26]hexaphyrin Pd(II) complex 2
2003 [4] reactivated the interest in synthetic challenge
to Möbius aromatic molecules [5]. Along this surge,
(Scheme 1) is intriguing. Oxidation of 1 with tris(p-
bromophenyl)aminium hexachloroantimonate gives 2
we have found that meso-aryl-substituted expanded
and reduction of 2 with NaCNBH3 produced 1, both
porphyrins serve a remarkably effective platform to
with Pd-migration and resultant concurrent topology
realize stable Möbius aromatic and antiaromatic systems,
change. The reduction of 2 to 1 can be considered to
in which the twisted conformations are often held by
proceed with regioselective hydride attack at the C(3)
metal coordination [6a, 6b] and fused structures [6c, 6d].
In many cases, [4np]expanded porphyrins tend to prefer
position [8]. We also explored the reaction of 2 with
triphenyl- and trialkylphosphines as a nucleophile
twisted conformations upon lowering temperature [6e,
to furnish C(3)-phosphinated Möbius aromatic
6f] or protonation [6g, 6h], to gain stabilization associated
hexaphyrins [9]. These phosphination reactions can
with Möbius aromatic electronic networks.
be also considered to proceed via regioselective
In order to use these Möbius aromatic expanded
nucleophilic attack at the C(3) position. In this
porphyrins as a component of functional systems,
paper, we extended this chemistry to regioselective
halogenations of 2. The resultant 3-brominated
Möbius aromatic hexaphyrin 4 was used for the Stille
◊SPP full and ◊◊student member in good standing
coupling reactions to provide 3-ethynylated Möbius
aromatic hexaphyrin Pd complexes.
*Correspondence to: Atsuhiro Osuka, email: osuka@kuchem.
kyoto-u.ac.jp, tel: +81 075-753-4008, fax: +81 075-753-3970
Copyright © 2013 World Scientific Publishing Company

666
T. YONEDA ET AL.
Br
Br
N+
Br
C6F5
C6F5
N
C6F5
H
N
–
SbX6
H
C6F5
N
(X = Cl or F)
N
N
HN
HN
C6F5
C6F5
Pd
C6F5
C6F5
C6F5
CH3CN
Pd
C(3)
HN
N
N
NaCNBH3
N
C(3)
H
THF
N
C6F5
C6F5
C6F5
1
2
Scheme 1. Redox interconversions between 1 and 2
887, and 953 nm, which are characteristic of aromatic
porphyrinoids and are slightly but distinctly red shifted
from those of the complex 1 (a Soret band at 618 nm and
Q-bands at 801, 880, and 956 (shoulder) nm). It has been
now concluded that Cl– ion should undergo nucleophilic
addition at the C(3) position of 2. We then thought that
RESULTS AND DISCUSSION
We reported the synthesis of [26]hexaphyrin Pd
complex 2 in 71% yield by the oxidation of [28]
hexaphyrin Pd complex 1 with tris(p-bromophenyl)
aminium hexachloroantimonate (Scheme 1, X=Cl) [8].
Careful examination of this reaction led to an isolation of
a small amount of blue compound, which was identified
as 3-chlorinated Möbius aromatic [28]hexaphyrin Pd(II)
complex 3. High-resolution electrospray ionization time-
of-flight mass spectrometry (HR-ESI-TOF MS) was fully
consistent with the structure (SI). The 1H NMR spectrum
of 3 exhibits a singlet signal due to the inner b-proton at
d = 0.59 ppm, a singlet signal due to the inner NH at d =
0.66 ppm, and peaks assignable to the outer b-protons are
observed in the range of d = 7.88–5.43 ppm, indicating
a diatropic ring current (SI), and the unambiguously
structural determination was accomplished through
single crystal X-ray diffraction analysis to be a twisted
conformation, in which the largest torsion angle in
the conjugation circuit (Drm) is 51°, and the harmonic
oscillator model of aromaticity (HOMA [10]) has been
calculated to be 0.35. (Fig. 1 and SI) It was thought that
the complex 3 was formed as a secondary product via
nucleophilic addition of Cl– ion at the C(3)-position of
2, similarly to the hydride and phosphine additions [8,
9]. On the basis of this consideration, we attempted the
reaction of 2 with Cl– ion and found that the reaction of
2 with aqueous HCl (10 equiv.) in acetonitrile proceeded
smoothly at room temperature to give 3 quantitatively
(Scheme 2). The UV-vis absorption spectrum of 3
exhibits a Soret band at 624 nm and Q-bands at 810,
tris(p-bromophenyl)aminium
hexafluoroantimonate
might be a better oxidant because F– ion is a harder and
less nucleophilic anion than Cl– ion. This was indeed
true, in that the oxidation of 1 with tris(p-bromophenyl)
aminium hexafluoroantimonate gave 2 in 91% yield with
excellent reproducibility (Scheme 1, X = F).
Then, we attempted the synthesis of 3-brominated
complex 4 by treatment of 2 with aqueous HBr, which
however gave 4 merely in a low yield due to HBr-triggered
facile demetalation. We thus examined the reaction of 2
with tetra-n-butyl-ammonium bromide, which led to the
reduction to give 1. After extensive experimentations,
we found that the reaction of 2 with 10 equiv. potassium
bromide and an equimolar p-toluenesulfonic acid in
acetonitrile at room temperature for 3 d gave 4 in 78%
1
yield (Scheme 3). The HR-ESI-TOF MS and H NMR
spectra of 4 are analogous to those of 3 in line with
the structural assignment (SI). The UV-vis absorption
spectrum of 4 exhibited a Soret band at 625 nm and
Q-bands at 810, 894, and 961 nm. We also examined the
synthesis of 3-fluorinated and iodinated Möbius aromatic
hexaphyrin Pd complexes. However, these attempts have
been unsuccessful so far.
With the halogenated Möbius aromatic molecules 3
and 4 in hand, we examined further fabrications. While 3
C6F5
C6F5
H
N
C6F5
H
N
C6F5
N
N
N
N
HN
HN
HCl (10 eq)
C6F5
C6F5
Pd
C6F5
C6F5
C6F5
N
Pd
CH3CN
room temp.
90 min
C(3)
HN
N
N
Cl–
Cl
C6F5
C6F5
C6F5
2
3 (quant.)
Scheme 2. Chlorination of 2
Copyright © 2013 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2013; 17: 666–672

REGIOSELECTIVE FABRICATIONS OF A MÖBIUS AROMATIC [28]HEXAPHYRIN PALLADIUM(II) COMPLEX
667
Fig. 1. (a) X-ray crystal structure and (b) schematic representation of p-orbital of 3. meso-Pentafluorophenyl substituents and solvent
molecules are omitted for clarity. The thermal ellipsoids are drawn at 50% probability level
C6F5
C6F5
H
N
C6F5
H
C6F5
N
KBr (10 eq)
N
N
N
N
HN
HN
p-TsOH•H2O (1 eq)
C6F5
C6F5
Pd
C6F5
C6F5
C6F5
N
Pd
CH3CN
room temp.
3 days
HN
N
N
Br
C6F5
C6F5
C6F5
2
4 (78%)
Scheme 3. Bromination of 2
R
Bu3Sn
(10 eq)
C6F5
C6F5
H
H
N
C6F5
C6F5
N
PEPPSITM-IPr
N
N
(1 eq)
HN
HN
HN
HN
C6F5
C6F5
C6F5
C6F5
C6F5
C6F5
N
Pd
Pd
THF
50 °C, 24 h
N
N
N
Br
C6F5
C6F5
R
4
iPr
iPr
5: R = Ph, 78%
N
N
6: R = SiMe3, 60%
iPr
Pd Cl
iPr
Cl
PEPPSITM-IPr =
TBAF (10 eq)
THF, 0 °C, 1 h
N
Cl
7: R = H, 80%
Scheme 4. Stille coupling reaction of 4
was rather unreactive, brominated complex 4 was found to
be reactive under Stille coupling conditions. The reaction
of 4 with 10 equiv. (phenylethynyl)tributylstannane
in the presence of an equiv. of PEPPSITM-IPr [11] in
THF under Ar atmosphere under reflux for 24 h gave
3-phenylethynylated [28]hexaphyrin 5 in 78% yield
(Scheme 4). Under the same conditions, Stille coupling
reactionof4with[(trimethylsilyl)ethynyl]tributylstannane
gave b-(trimethylsilyl)ethynylated [28]hexaphyrin 6 in
60% yield. The trimethylsilyl group of 6 was eliminated
by the addition of tetrabutylammonium fluoride in THF
at 0 °C to give b-ethynylated hexaphyrin 7 in 80% yield
(Scheme 4). Further, similar reaction was applied to
synthesis of 3-(tributylstannyl)ethynyl [28]hexaphyrin
Pd(II) complex 8 via the reaction of 4 with a large excess
amount of bis-(tributylstannyl)acetylene in 46% yield
(Scheme 5). This complex 8, which was certainly stable
under air or on silica-gel column chromatography, was
Copyright © 2012 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2013; 17: 667–672

668
T. YONEDA ET AL.
SnBu3
(10 eq)
PEPPSITM-IPr
Bu3Sn
C6F5
C6F5
H
H
C6F5
C6F5
N
N
(1 eq)
N
N
HN
HN
HN
HN
C6F5
C6F5
C6F5
C6F5
C6F5
N
C6F5
Pd
Pd
THF
50 °C, 20 h
N
N
N
Br
C6F5
C6F5
SnBu3
4
8 (46%)
Br
C6F5
H
(10 eq)
PEPPSITM-IPr
(1 eq)
C6F5
N
N
HN
HN
C6F5
C6F5
C6F5
Pd
THF
50 °C, 24 h
N
N
C6F5
9 (35%)
Scheme 5. Syntheses of 8 and 9 from 4
used for the Stille coupling with 9-bromoanthracene in the
presence of PEPPSITM-IPr to provide complex 9 in 35%
yield. The structures of 5–9 were all fully substantiated by
HR-ESI-TOF MS and 1H NMR spectra. The NMR spectra
of 5–9 indicate the signals due to inner b-protons, NH
protons, and outer b-protons at the range of d = 0.60–0.75
ppm, 0.70–0.77 ppm, and 7.89–5.41 ppm, respectively,
which indicate a strong diatropic ring current typical of
[28]Möbius aromatic hexaphyrin Pd complexes. The
UV-vis absorption spectra of 5–9 all display the features
characteristic of [28]Möbius aromatic hexaphyrin Pd
complexes with a Soret band at 630, 630, 629, 628, and
630 nm, respectively, and Q-band like bands (SI). These
absorption spectra are slightly red-shifted with regard to
those of 1, 3, and 4, reflecting the elongated conjugations
by the ethynyl groups [12].
all spectroscopic studies. Silica gel column chromatography
was performed on Wakogel C-300 or C-400. Thin-layer
chromatography (TLC) was carried out on aluminum sheets
coated with silica-gel 60 F254 (Merck 5554)
UV-visible spectra were recorded on a Shimadzu
1
UV-3100PC spectrometer. H, 13C and 16F NMR spectra
were recorded on a JEOL ECA-600 spectrometer
1
(operating as 600.17 MHz for H, 150.91 MHz for 13C,
and 564.73 MHz for 19F) using the residual solvent as the
internal reference for 1H (d = 7.26 ppm in CDCl3), 13C (d
= 77.16 ppm in CDCl3), or Hexafluorobenzene for 19F
(d = -162.9 ppm) was employed as external references.
High-resolution electrospray-ionization time-of-flight
mass spectroscopy (HR-ESI-TOF-MS) was recorded on
a BRUKER microTOF model using negative mode for
acetonitrile solutions of sample.
In summary, 3-chlorinated and 3-brominated Möbius
aromatic hexaphyrin Pd(II) complexes 3 and 4 were
prepared by the nucleophilic reaction of Hückel aromatic
hexaphyrin 2. Complex 4 was transformed into several
3-ethynylated Möbius aromatic hexaphyrin Pd(II)
complexes 5–9 with reservation of twisted Möbius
structures. Further modifications of Möbius aromatic
hexaphyrin Pd(II) complex are now actively explored in
our laboratory.
Crystal data
X-ray crystallographic data for compound 3 was
collected at -180 °C with a Rigaku RAXIS-RAPID
diffraction by using graphite monochromated Cu-Ka
radiation (l = 1.54187 Å). The structures were solved by
direct method (SHELXS-97).
3. C66H13N6F30Cl1Pd1, 4(C3H6O1), Mw = 1833.99,
triclinic, space group P-1 (No. 2), a = 7.4820(14) Å, b
= 17.726(2) Å, c = 27.064(3) Å, a = 91.987(14)°, b =
92.175(13)°, g =96.766(14)°, V= 3559.0(9) Å3, T = 93 K,
EXPERIMENTAL
r
calcd = 1.711 g.cm–3, Z = 2, R1 = 0.1543 (I > 2s (I)), Rw =
0.4193 (all data), GOF = 1.039.
General
Synthesis
All reagents were of the commercial grade and were
used without further purification except where noted. The
spectroscopic grade dichloromethane was used as solvent for
Improved synthesis of meso-hexakis(pentafluoro-
phenyl)-substituted [26]hexaphyrin(1.1.1.1.1.1) Pd(II)
Copyright © 2013 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2013; 17: 668–672

REGIOSELECTIVE FABRICATIONS OF A MÖBIUS AROMATIC [28]HEXAPHYRIN PALLADIUM(II) COMPLEX
669
complex 2. An CH3CN solution (50 mL) of [28]
3-bromo-meso-hexakis(pentafluorophenyl)-
substituted [28]hexaphyrin(1.1.1.1.1.1) Pd(II)
hexaphyrin mono-Pd(II) complex 1 (157 mg, 0.10 mmol)
was stirred in the presence of tris(4-bromophenyl)
aminium hexafluoroantimonate (179 mg, 0.25 mmol)
for 15 min under ambient conditions. After addition
of CH2Cl2 and one portion of methanol, the reaction
mixture was washed with water and the products were
extracted with CH2Cl2. The organic extract was dried
over anhydrous Na2SO4, and the solvent was evaporated
under reduced pressure. The residue was then purified
by silica-gel chromatography using CH2Cl2 as an eluent.
[26]Hexaphyrin mono-PdII complex 2 was eluted as a
violet band. Recrystallization from CH2Cl2 and hexane
gave 2 as purple crystals (143 mg, 91%).
complex 4. A CH3CN solution (80 mL) of 2 (62.4 mg,
40 mmol) and potassium bromide (47.6 mg, 10 equiv.)
was stirred in the presence of p-toluenesulfonic acid (7.6
mg, 1.0 equiv.) for three days at room temperature. The
reaction mixture was passed through a short silica-gel
column with CH2Cl2. The solvent was evaporated under
reduced pressure. The residue was then purified by silica-
gel column chromatography using a 1:4 mixture of diethyl
ether and hexane as an eluent. The first blue fraction of
3-brominated [28]hexaphyrin mono-PdII complex 4 was
1
obtained as blue solids in 78% yield (51 mg). H NMR
(600 MHz, CDCl3): d, ppm 9.55 (s, 1H; NH), 7.90 (d, J
= 4.8 Hz, 1H, b), 7.78 (d, J = 4.8 Hz, 1H, b), 7.76 (d, J =
4.8 Hz, 1H; b), 7.68 (d, J = 4.2 Hz, 2H; b), 7.66 (d, J =
4.8 Hz, 1H, b), 7.59 (d, J = 4.8 Hz, 1H; b), 7.30 (s, 1H,
b), 6.78 (dd, J = 4.1, 2.5 Hz, 1H; b), 5.43 (dd, J = 4.4,
2.8 Hz, 1H; b), 4.39 (s, 1H, NH), 0.66 (s, 1H, NH), and
0.55 (d, J = 1.4 Hz, 1H; b). 13C NMR (151 MHz, CDCl3):
d, ppm 153.6, 148.6, 148.5, 144.6, 143.7, 143.0, 142.6,
139.6, 138.5, 135.5, 134.4, 133.9, 131.7, 131.3, 128.4,
128.1, 127.7, 127.5, 127.2, 126.2, 125.6, 121.4, 119.2,
114.2, 106.7, 102.5, 95.7, 91.5, and 88.8. The signals
for meso-pentafluorophenyl carbons were not observed
clearly because of their weak intensity. 19F NMR (565
MHz, CDCl3): d, ppm -135.0 (d, J = 20.7 Hz, 1F; o-F),
-135.8 (d, J = 31.1 Hz, 1F; o-F), -136.1 (m, 1F; o-F),
-136.4 (d, J = 24.2 Hz, 1F; o-F), -136.6 (m, 1F; o-F),
-137.2 (d, J = 20.7 Hz, 1F; o-F), -137.8 (t, J = 31.1 Hz,
1F; o-F), -138.3 (m, 1F; o-F), -138.8 (d, J = 31.1 Hz, 1F;
o-F), -139.1 (d, J = 24.2 Hz, 1F; o-F), -141.7 (s, 1F; o-F),
-150.0 (t, J = 20.7 Hz, 1F; p-F), -150.7 (t, J = 19.5 Hz, 1F;
p-F), -151.3 (t, J = 24.2 Hz, 1F; p-F), -152.5 (t, J = 20.7
Hz, 1F; p-F), -153.1 (t, J = 18.7 Hz, 1F; p-F), -154.9 (t, J
= 20.7 Hz, 1F; p-F), -159.2 - -159.6 (m, 3F; m-F), -159.8
(m, 1F; m-F), -160.1 (m, 2F; m-F), -161.4 (td, J = 24.2,
6.9 Hz, 1F; m-F), -161.6 (td, J = 24.2, 6.9 Hz, 1F; m-F),
-162.3 (m, 1F; m-F), -163.3 (m, 1F; m-F), -163.3 (m, 1F;
m-F), and -167.8 (m, 1F; m-F). ESI-MS: m/z 1644.8853
[M - H]–; calcd. for C66H13N6F30Cl1Pd1:1644.8853.
UV-vis (CH2Cl2): l, nm (e, M–1.cm–1) 392 (25000), 625
(120000), 810 (5900), 884 (8900), and 961 (4800).
3-(2-phenylethynyl) meso-hexakis(pentafluorop-
henyl)-substituted [28]hexaphyrin(1.1.1.1.1.1) Pd(II)
complex 5. A dry Schlenk flask containing 4 (15 mg,
10 mmol), (phenylethynyl)tributylstannane (26.5 mg,
10 equiv.), PEPPSITM-IPr (6.8 mg, 1.0 equiv.) was filled
with Ar, to which were added freshly distilled THF (1
mL). The reaction mixture was refluxed for 24 h under
Ar atmosphere. The reaction mixture was passed through
a short silica gel column followed by evaporation of the
solvent. The residue was separated by silica gel column
chromatography using a mixture of ether and hexane as
an eluent. The first blue fraction of 3-ethynylphenyl [28]
hexaphyrin mono-PdII complex 5 was obtained as blue
solids in 78% yield (12 mg). 1H NMR (600 MHz, CDCl3):
3-chloro
meso-hexakis(pentafluorophenyl)-sub-
stituted [28]hexaphyrin(1.1.1.1.1.1) Pd(II) complex 3.
A CH3CN solution (20 mL) of 2 (15 mg, 10 mmol) was
stirred in the presence of aqueous 1.0 M HCl (0.1 mL,
10 equiv.) for 90 min at room temperature. The reaction
mixture was washed with aqueous Na2CO3 and the
products were extracted with CH2Cl2. The organic extract
was dried over anhydrous Na2SO4, and the solvent was
evaporated under reduced pressure. The residue was
then purified by silica-gel column chromatography using
a 1:2 mixture of CH2Cl2 and hexane as an eluent. The
3-chlorinated [28]hexaphyrin mono-PdII complex 3 was
obtained as blue solids in quantitative yield (16 mg). 1H
NMR (600 MHz, CDCl3): d, ppm 9.60 (s, 1H; NH), 7.88
(d, J = 4.5 Hz, 1H, b), 7.78 (d, J = 4.8 Hz, 1H, b), 7.76
(d, J = 4.8 Hz, 1H; b), 7.68 (d, J = 4.8 Hz, 2H; b), 7.65
(d, J = 4.5 Hz, 1H, b), 7.58 (d, J = 4.8 Hz, 1H; b), 7.15
(s, 1H, b), 6.77 (dd, J = 4.2, 2.8 Hz, 1H; b), 5.43 (dd,
J = 4.2, 2.8 Hz, 1H; b), 4.42 (s, 1H, NH), 0.66 (s, 1H,
NH), and 0.59 (d, J = 1.8 Hz, 1H; b). 13C NMR (165
MHz, CDCl3): d, ppm 153.5, 152.2, 150.1, 148.6, 148.2,
144.6, 143.7, 142.8, 142.5, 139.9, 139.2, 138.4, 135.4,
134.3, 133.9, 131.6, 131.1, 128.4, 128.2, 127.7, 127.4,
127.1, 125.7, 125.0, 122.4, 122.0, 121.4, 114.1, 102.7,
and 91.4. The signals for the meso-pentafluorophenyl
carbons were not observed clearly because of their weak
intensity. 19F NMR (565 MHz, CDCl3): d, ppm -135.0
(d, J = 20.7 Hz, 1F; o-F), -136.1 (d, J = 20.7 Hz, 2F;
o-F), -136.4 (d, J = 28.9 Hz, 1F; o-F), -136.5 (m, 1F;
o-F), -137.2 (m, 1F; o-F), -137.4 (d, J = 20.7 Hz, 1F;
o-F), -137.8 (m, 1F; o-F), -138.4 (brs, 1F; o-F), -139.0
(d, J = 28.9 Hz, 1F; o-F), -139.1 (d, J = 20.7 Hz, 1F;
o-F), -141.8 (s, 1F; o-F), -150.0 (t, J = 20.7 Hz, 1F; p-F),
-150.8 (t, J = 20.7 Hz, 1F; p-F), -151.3 (t, J = 20.7 Hz,
1F; p-F), -152.5 (t, J = 20.7 Hz, 1F; p-F), -153.1 (t, J
= 20.7 Hz, 1F; p-F), -155.0 (br s, 1F; p-F), -159.4 (m,
3F; m-F), -159.9 (brs, 1F; m-F), -160.2 (m, 1F; m-F),
-161.4 (t, J = 17.3 Hz, 1F; m-F), -161.6 (m, 1F; m-F),
-162.4 (m, 2F; m-F), -163.2 (m, 1F; m-F), and -167.8 (m,
1F; m-F). ESI-MS: m/z 1600.9345 [M - H]–; calcd. for
C66H13N6F30Cl1Pd1:1600.9379. UV-vis (CH2Cl2): l, nm
(e, M–1.cm–1) 392 (28000), 624 (139000), 810 (7900),
887 (10000), and 953 (sh, 5600).
Copyright © 2012 World Scientific Publishing Company
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670
T. YONEDA ET AL.
d, ppm 9.54 (s, 1H; NH), 7.85 (d, J = 6.0 Hz, 1H, b), 7.78
(d, J = 4.8 Hz, 1H, b), 7.76 (d, J = 4.8 Hz, 1H; b), 7.68 (d,
J = 4.8 Hz, 1H; b), 7.63 (d, J = 6.0 Hz, 1H, b), 7.59 (d, J =
4.8 Hz, 1H; b), 7.44 (s, 1H, b), 7.35–7.25 (m, 3H, Ph-H),
7.18 (dd, J = 7.7, 1.8 Hz, 2H, Ph-H), 6.78 (dd, J = 4.1,
1.9 Hz, 1H; b), 5.43 (dd, J = 4.1, 1.9 Hz, 1H; b), 4.55 (s,
1H, NH), 0.73 (s, 1H, NH), and 0.64 (d, J = 1.9 Hz, 1H;
b). 13C NMR (151 MHz, CDCl3): d, ppm 155.0, 154.2,
148.9, 148.5, 144.6, 143.8, 143.3, 143.1, 142.5, 138.4,
135.2, 134.4, 134.1, 131.8, 131.5, 130.9. 130.8, 129.2,
128.7, 128.5, 128.2, 127.8, 127.7, 127.3, 127.2, 122.3,
121.4, 119.7, 114.2, 106.7, 102.8, 102.4, 96.4, 91.6, 88.5,
and 82.2. The signals for the meso-pentafluorophenyl
carbons were not observed clearly because of their weak
intensity. 19F NMR (565 MHz, CDCl3): d, ppm -136.3
(d, J = 17.3 Hz, 1F; o-F), -137.2 (d, J = 31.1 Hz, 2F;
o-F), -137.6 (d, J = 24.2 Hz, 1F; o-F), -137.8 (m, 1F;
o-F), -138.3 (d, J = 17.3 Hz, 1F; o-F), -138.6 (d, J = 24.2
Hz, 1F; o-F), -139.0 (m, 1F; o-F), -139.6 (m, 1F; o-F),
-139.9 (d, 1F, J = 24.2 Hz,; o-F), -140.4 (d, J = 20.7 Hz,
1F; o-F), -143.1 (m, 1F; o-F), -151.4 (t, J = 24.2 Hz, 1F;
p-F), -152.1 (t, J = 20.7 Hz, 1F; p-F), -152.7 (t, J = 20.7
Hz, 1F; p-F), -153.9 (t, J = 20.7 Hz, 1F; p-F), -154.5 (t,
J = 20.7 Hz, 1F; p-F), -156.4 (t, J = 13.8 Hz, 1F; p-F),
-160.6–160.9 (m, 3F; m-F), -161.2 (m, 1F; m-F), -161.4
(m, 2F; m-F), -162.7 (m, 1F; m-F), -163.0 (m, 1F; m-F),
-164.3 (m, 2F; m-F), -164.7 (m, 1F; m-F), and -169.0 (m,
1F; m-F). ESI-MS: m/z 1665.0061 [M - H]–; calcd. for
C74H18N6F30Pd1:1665.0088. UV-vis (CH2Cl2): l, nm (e,
M–1.cm–1) 394 (25000), 630 (130000), 813 (7500), and
894 (8800).
The signals for the meso-pentafluorophenyl carbons were
not observed clearly because of their weak intensity.19F
NMR (565 MHz, CDCl3): d, ppm -135.1 (d, J = 24.2 Hz,
1F; o-F), -136.1 (m, 2F; o-F), -136.4 (dd, J = 24.2, 6.9
Hz, 1F; o-F), -136.6 (m, 1F; o-F), -137.0 (d, J = 20.7 Hz,
1F; o-F), -137.4 (d, J = 20.7 Hz, 1F; o-F), -137.7 (d, J =
27.7 Hz, 1F; o-F), -138.3 (brs, 1F; o-F), -138.8 (d, 1F, J
= 24.2 Hz,; o-F), -139.2 (d, J = 24.2 Hz, 1F; o-F), -141.9
(s, 1F; o-F), -150.1 (t, J = 20.7 Hz, 1F; p-F), -150.2 (t, J =
20.7 Hz, 1F; p-F), -151.4 (t, J = 20.7 Hz, 1F; p-F), -152.6
(t, J = 20.7 Hz, 1F; p-F), -153.0 (t, J = 24.2 Hz, 1F; p-F),
-155.1 (t, J = 19.0 Hz, 1F; p-F), -159.3 - -159.6 (m, 3F;
m-F), -159.9 (m, 1F; m-F), -160.2 (m, 2F; m-F), -161.5
(td, J = 20.7 Hz, 6.9 Hz, 1F; m-F), -161.7 (td, J = 24.2 Hz,
6.9 Hz, 1F; m-F), -162.6 (td, J = 20.7, 6.9 Hz, 1F; m-F),
-162.9 (td, J = 20.7 Hz, 6.9 Hz, 1F; m-F), -163.4 (m, 1F;
m-F), and -167.8 (m, 1F; m-F). ESI-MS: m/z 1665.0163
[M - H]–; calcd. for C74H18N6F30Pd1:1661.0180. UV-vis
(CH2Cl2): l, nm (e, M–1.cm–1) 394 (25000), 630 (1300),
814 (7700), and 891 (9100).
3-ethynyl meso-hexakis(pentafluorophenyl)-sub-
stituted [28]hexaphyrin(1.1.1.1.1.1) Pd(II) complex 7.
A THF (10 mL) solution of 6 (17 mg, 10 mmol),
tetrabutylammonium fluoride (100 mL of 1.0 M THF
solution, 10 equiv.) was stirred for 60 min at 0 °C under
N2 atmosphere. After addition of CH2Cl2, the reaction
mixture was washed with water and the products were
extracted with CH2Cl2. The organic extract was dried
over anhydrous Na2SO4, and the solvent was evaporated
under reduced pressure. The residue was then purified by
silica-gel chromatography using a mixture of CH2Cl2 and
hexane as an eluent. The first blue fraction of 3-ethynyl
[28]hexaphyrin mono-PdII complex 7 was obtained as
3-[2-(trimethylsilyl)ethynyl] meso-hexakis(penta-
fluorophenyl)-substituted [28]hexaphyrin(1.1.1.1.1.1)
Pd(II) complex 6. A dry Schlenk flask containing 4
(41 mg, 25 mmol), tributyl(trimethylsilylethynyl)tin (92
mL, 10 equiv.) and PEPPSITM-IPr (17 mg, 1.0 equiv.)
was filled with Ar, to which was added dry THF (5 mL).
The reaction mixture was refluxed for 24 h under Ar
atmosphere. The reaction mixture was passed through a
short silica gel column followed by evaporation of the
solvent. The residue was separated by silica gel column
chromatography using a mixture of ether and hexane
as an eluent. 3-(Trimethylsilyl)ethynyl [28]hexaphyrin
mono-PdII complex 6 was obtained as first blue fraction.
Recrystallization from CH2Cl2 and hexane gave as black
1
blue solids in 80% yield (13 mg). H NMR (600 MHz,
CDCl3): d, ppm 9.55 (s, 1H; NH), 7.87 (d, J = 4.1 Hz,
1H, b), 7.80 (d, J = 13.7 Hz, 1H, b), 7.77 (d, J = 5.0 Hz,
1H; b), 7.69 (d, J = 3.7 Hz, 2H; b), 7.64 (d, J = 5.0 Hz,
1H, b), 7.64 (d, J = 4.6 Hz, 1H; b), 7.46 (s), 6.78 (dd, J
= 4.6, 2.8 Hz, b), 5.43 (d, J = 2.8 Hz, 1H; b), 4.50 (s,
1H, NH), 3.47 (s, 1H, acetylene-H), 0.70 (s, 1H, NH)
and 0.60 (d, J = 1.9 Hz, 1H; b). 13C NMR (151 MHz,
CDCl3): d, ppm 153.4, 149.3, 148.4, 147.9, 144.6, 143.8,
143.6, 143.1, 143.6, 143.1, 142.8, 142.4, 138.4, 135.2,
134.4, 134.1, 131.7, 131.0, 130.0, 130.0, 129.1, 128.4,
128.2, 127.8, 127.3, 121.5, 119.9, 114.4, 106.6, 102.3,
96.1, 91.8, 90.2, 89.1 and 88.4. The signals for the meso-
pentafluorophenyl carbons were not observed clearly
because of their weak intensity. 19F NMR (565 MHz,
CDCl3): d, ppm -136.3 (d, J = 20.7 Hz, 1F; o-F), -137.4
(d, J = 24.2 Hz, 2F; o-F), -137.6 (d, J = 24.2 Hz, 1F; o-F),
-137.8 (m, 1F; o-F), -138.3 (d, J = 24.2 Hz, 1F; o-F),
-138.6 (d, J = 20.7 Hz, 1F; o-F), -139.0 (t, J = 24.2 Hz,
1F; o-F), -139.5 (m, 1F; o-F), -140.0 (dd, J = 24.2, 6.9
Hz, 1F; o-F), -140.4 (d, J = 20.7 Hz, 1F; o-F), -143.2 (m,
1F; o-F), -151.3 (t, J = 20.7 Hz, 1F; p-F), -152.0 (t, J =
20.7 Hz, 1F; p-F), -152.6 (t, J = 20.7 Hz, 1F; p-F), -153.8
(t, J = 20.7 Hz, 1F; p-F), -155.4 (t, J = 20.7 Hz, 1F; p-F),
1
crystals (25 mg, 60%). H NMR (600 MHz, CDCl3): d,
ppm 9.54 (s, 1H; NH), 7.89 (d, J = 5.0 Hz, 1H, b), 7.78
(d, J = 4.6 Hz, 1H, b), 7.76 (d, J = 4.6 Hz, 1H; b), 7.68
(d, J = 5.5 Hz, 2H; b), 7.64 (d, J = 5.5 Hz, 1H, b), 7.59
(d, J = 4.6 Hz, 1H; b), 7.45 (s), 6.77 (dd, 4.1, 2.5 Hz, b),
5.41 (dd, J = 4.1, 2.5 Hz, 1H; b), 4.54 (s, 1H, NH), 0.73
(s, 1H, NH) 0.60 (d, J = 1.9 Hz, 1H; b), and 0.10 (s, 9H;
Si(CH3)3). 13C NMR (151 MHz, CDCl3): d, ppm 153.7,
153.3, 149.0, 148.3, 147.0, 145.3, 144.5, 143.6, 143.2,
143.0, 142.4, 138.2, 135.1, 134.3, 134.0, 131.6, 131.1,
130.8, 129.4, 128.3, 128.1, 127.6, 127.2, 121.3, 119.6,
114.2, 108.7, 106.5, 102.2, 97.1, 96.1, 91.5, and -0.4.
Copyright © 2013 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2013; 17: 670–672

REGIOSELECTIVE FABRICATIONS OF A MÖBIUS AROMATIC [28]HEXAPHYRIN PALLADIUM(II) COMPLEX
671
-156.2 (t, J = 19.0 Hz, 1F; p-F), -160.6 (m, 2F; m-F),
Pd(II) complex 9. A dry Schlenk flask containing 8 (26
mg, 14 mmol), and PEPPSITM-IPr (35 mg, 10 equiv.) was
filled with Ar, to which was added dry THF (1 mL). The
reaction mixture was stirred for 24 h underAr atmosphere
at 50 °C. The reaction mixture was passed through a
short silica gel column followed by evaporation of the
solvent. The residue was separated by silica gel column
chromatography using a mixture of ether and hexane as
an eluent. 3-(Tributylstannyl)ethynyl [28]hexaphyrin
mono-PdII complex 9 was obtained as blue solids (8.6
-160.8 (td, J = 22.4, 6.9 Hz; m-F), -161.1 (t, J = 20.7
Hz, 1F; m-F), -161.4 (m, 2F; m-F), -162.7 (td, J = 22.4,
10.3 Hz, 1F; m-F), -162.9 (td, J = 22.4, 6.9 Hz 1F; m-F),
-164.4 (m, 2F; m-F), -164.6 (m, 1F; m-F), and -169.0 (m,
1F; m-F). ESI-MS: m/z 1588.9792 [M - H]–; calcd. for
C74H18N6F30Pd1:1588.9774. UV-vis (CH2Cl2): l, nm (e,
M–1.cm–1) 395 (23000), 629 (13000), 814 (7100), and
895 (7900).
3-[2-(tributylstannyl)ethynyl] meso-hexakis(penta-
fluorophenyl)-substituted [28]hexaphyrin(1.1.1.1.1.1)
Pd(II) complex 8. A dry Schlenk flask containing 4
(32.9 mg, 20 mmol), bis-(tributylstannyl)acetylene (101
mL, 10 equiv.) and PEPPSITM-IPr (14 mg, 1.0 equiv.) was
filled with Ar, to which was added dry THF (4 mL). The
reaction mixture was stirred for 20 h underAr atmosphere
at 50 °C. The reaction mixture was passed through a
short silica gel column followed by evaporation of the
solvent. The residue was separated by silica gel column
chromatography using a mixture of ether and hexane as
an eluent. The first blue fraction of 3-(tributylstannyl)
ethynyl [28]hexaphyrin mono-PdII complex 8 was
1
mg, 35%). H NMR (600 MHz, CDCl3): d, ppm 9.61
(s, 1H; NH), 8.46 (s, 1H, anthryl-H) 8.16–8.14 (m, 2H,
anthryl-H), 8.02–8.00 (m, 2H, anthryl-H), 7.86 (m, 1H,
b), 7.78–7.77 (m, 2H; b), 7.71 (d, J = 6.0 Hz, 1H; b), 7.65
(m, J = 1H, b), 7.61 (s, 1H; b), 7.53 (d, J = 6.0 Hz), 7.50–
7.48 (m, 4H, anthryl-H) 6.79 (dd, J = 4.6, 2.3 Hz, b), 5.47
(d, J = 6.4 Hz, 1H; b), 4.61 (s, 1H, NH), 0.75 (d, J = 1.7
Hz, 1H, b), and 0.74 (s, 1H, NH). 13C NMR (151 MHz,
CDCl3): d, ppm 154.2, 153.4, 148.9, 148.6, 144.6, 143.6,
143.2, 142.5, 135.4, 141.2, 139.2, 138.5, 134.2, 134.0,
132.1, 131.8, 131.7, 131.1, 130.9, 129.0, 128.9, 128.5,
128.2, 127.7, 127.4, 127.3, 127.2, 126.0, 125.9, 121.5,
119.6, 115.8, 114.2, 111.1, 106.6, 102.4, 99.5, 93.1,
91.7, and 88.6. The signals for meso-pentafluorophenyl
carbons were not observed clearly because of their weak
intensity. 19F NMR (565 MHz, CDCl3): d, ppm -136.3 (d,
J = 24.1 Hz, 1F; o-F), -137.1 (m, 1F; o-F), -137.5 (dd, J
= 24.1, 6.9 Hz, 2F; o-F), -137.6 (d, J = 24.1, 6.9 Hz, 1F;
o-F), -138.4 (d, J = 20.7 Hz, 1F; o-F), -139.0 (t, J = 27.7
Hz, 1F; o-F), -139.6 (m, 1F; o-F), -140.3 (d, J = 20.7 Hz,
1F; o-F), -140.5 (dd, J = 24.2, 6.9 Hz, 1F; o-F), -143.1 (s,
1F; o-F), -151.4 (t, J = 20.7 Hz, 1F; p-F), -152.0 (t, J =
20.7 Hz, 1F; p-F), -152.7 (t, J = 20.7 Hz, 1F; p-F), -153.9
(t, J = 20.7 Hz, 1F; p-F), -155.1 (t, J = 20.7 Hz, 1F; p-F),
-160.6–-160.8 (m, 3F; p-F), -161.1 (m, 1F, m-F), -161.4
(m, 2F, m-F), -162.7 (m, 1F, m-F), -164.0 (m, 2F, m-F),
-164.2 (m, 1F, m-F), -164.6 (m, 1F, m-F), and -169.0 (m,
1F; m-F). ESI-MS: m/z 1765.0420 [M - H]–; calcd. for
C82H22F30N6Pd1:1765.0414. UV-vis (CH2Cl2): l, nm (e,
M–1.cm–1) 390 (29000), 630 (10800), 815 (6800), and
892 (7800).
1
obtained as blue solids (17 mg, 46%). H NMR (600
MHz, CDCl3): d, ppm 9.50 (s, 1H; NH), 7.85 (dd, J =
5.0, 1.0 Hz, 1H, b), 7.77 (d, J = 5.0 Hz, 1H, b), 7.74 (d, J
= 5.0 Hz, 1H; b), 7.67 (dd, J = 4 Hz, 2H; b), 7.63 (d, J =
5.0, 1.0 Hz, 1H, b), 7.57 (d, J = 5.0 Hz, 1H; b), 7.35 (s),
6.76 (dd, J = 4.1, 2.3 Hz, 1H; b), 5.43 (dd, J = 4.1, 2.8 Hz,
1H; b), 4.59 (s, 1H, NH), 1.6–1.2 (m, 14H, butyl-H), 1.0–
0.9 (m, 4H, butyl-H) 0.87 (t, J = 7.2 Hz, 9H, butyl-CH3),
0.77 (s, 1H, NH), and 0.71 (d, J = 5.0 Hz, 1H, b). 13C
NMR (151 MHz, CDCl3): d, ppm 154.3, 153.5, 148.6,
148.3, 144.5, 143.6, 143.6, 142.9, 142.3, 138.4, 135.2,
134.3, 134.2, 132.4, 131.6, 130.9, 129.3, 128.5, 128.1,
127.6, 127.3, 127.3, 121.1, 119.7, 113.9, 109.5, 106.6,
102.3, 101.9, 96.3, 91.3, 88.3, 29.0, 27.2, 13.7, and 11.2.
The signals for the meso-pentafluorophenyl carbons were
not observed clearly because of their weak intensity. 19
F
NMR (565 MHz, CDCl3): d, ppm -135.1 (d, J = 24.1 Hz,
1F; o-F), -136.1 (dd, J = 24.1, 8.6 Hz, 1F; o-F), -136.4
(dd, J = 24.1, 6.9 Hz, 2F; o-F), -137.3 (d, J = 20.7 Hz, 1F;
o-F), -137.7 (t, J = 25.9 Hz, 1F; o-F), -138.4 (m, 1F; o-F),
-139.2 (d, J = 20.7 Hz, 1F; o-F), -141.8 (m, 1F; o-F),
-150.2 (t, J = 20.7 Hz, 1F; p-F), -151.0 (t, J = 20.7 Hz, 1F;
p-F), -151.6 (t, J = 22.4 Hz, 1F; p-F), -152.7 (t, J = 20.7
Hz, 1F; p-F), -153.8 (t, J = 20.7 Hz, 1F; p-F), -155.2 (t, J
= 20.7 Hz, 1F; p-F), -159.3 - -159.6 (m, 3F; m-F), -160.0
(t, J = 19.0 Hz; m-F), -160.2–-160.5 (m, 2F; m-F), -161.5
(td, J = 22.4, 6.9 Hz, 1F; m-F), -161.7 (td, J = 20.7, 6.9
Hz, 1F; m-F), -162.7 (t, J = 20.7 Hz, 1F; m-F), -162.8 (t,
J = 20.7 Hz, 2F; m-F), -163.5 (m, 1F; m-F), and -167.8
(m, 1F; m-F). ESI-MS: m/z 1879.0845 [M - H]–; calcd.
for C80H40N6F30Pd1Sn1:1879.0849. UV-vis (CH2Cl2): l,
nm (e, M–1.cm–1) 392 (24000), 628 (11700), 814 (7200),
and 892 (8400).
Acknowledgements
This work was supported by Grants-in-Aid (No.
22245006 (A), and 20108001 “pi-Space”) from MEXT,
Japan. T.Y. thanks JSPS for Research Fellowship for
Young Scientists. The authors thank Prof. K. Okada, Dr.
S. Suzuki, and X. Zhang (Osaka City University) for
fruitful discussions.
Supporting information
Figures of NMR spectra, HR-ESI-TOF MS spectra,
UV-vis absorption spectra and crystallographic data
(Figs S1-S4) are given in the supplementary material.
This material is available free of charge via the Internet
at http://www.worldscinet.com/jpp/jpp.shtml.
3-[2-(9-anthryl)ethynyl] meso-hexakis(pentafluo-
rophenyl)-substituted
[28]hexaphyrin(1.1.1.1.1.1)
Copyright © 2012 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2013; 17: 671–672

672
T. YONEDA ET AL.
Crystallographic data have been deposited at the
Cambridge Crystallographic Data Centre (CCDC) under
number CCDC-903593. Copies can be obtained on
request, free of charge, via www.ccdc.cam.ac.uk/data_
request/cif or from the Cambridge Crystallographic Data
Centre, 12 Union Road, Cambridge CB2 1EZ, UK (fax:
+44 1223-336-033 or email: deposit@ccdc.cam.ac.uk).
Int. Ed. 2008; 47: 681–684. b) Park JK, Yoon ZS,
Yoon M-C, Kim KS, Mori S, Shin J-Y, Osuka A
and Kim D. J. Am. Chem. Soc. 2008; 130: 1824–
1825. c) Tokuji S, Shin J-Y, Kim KS, Lim JM,
Youfu K, Saito S, Kim D and Osuka A. J. Am.
Chem. Soc. 2009; 131: 7240–7241. d) Inoue M,
Kim KS, Suzuki M, Lim JM, Shin JY, Kim D and
Osuka A. Angew. Chem. Int. Ed. 2009; 48: 6687–
6690. e) Sankar J, Mori S, Saito S, Rath H, Suzuki
M, Inokuma Y, Shinokubo H, Kim KS, Yoon ZS,
Shin J-Y, Lim JM, Matsuzaki Y, Matsushita O,
Muranaka A, Kobayashi N, Kim D and Osuka A. J.
Am. Chem. Soc. 2008; 130: 13568–13579. f) Kim
KS, Yoon ZS, Ricks AB, Shin J-Y, Mori S, Sankar
J, Saito S, Jung YM, Wasielewski MR, Osuka A
and Kim D. J. Phys. Chem. A 2009; 113: 4498–
4506. g) Saito S, Shin J-Y, Lim JM, Kim KS, Kim
D and Osuka A. Angew. Chem. Int. Ed. 2008; 47:
9657–9660. h) Lim JM, Shin J-Y, Tanaka Y, Saito
S, Osuka A and Kim D. J. Am. Chem. Soc. 2010;
132: 3105–3114.
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