Synthesis and characterization of fully conjugated porphyrin tapes

Article abstract of DOI:10.1560/E7HT-FH7B-7651-3HCN

meso-meso, β-β, β-β Triply-linked zinc(II) porphyrin tapes were synthesized by powerful oxidation of meso-meso-linked zinc(II) porphyrin arrays up to tetramers with DDQ-Sc(OTf)₃. Coordination of butylamine to zinc(II) ions of porphyrin rings di

Full text of DOI:10.1560/E7HT-FH7B-7651-3HCN

Synthesis and Characterization of Fully Conjugated Porphyrin Tapes
TAKAHISA IKEUE, NAOKI ARATANI, AND ATSUHIRO OSUKA*
Department of Chemistry, Graduate School of Science, Kyoto University and Core Research for Evolutional Science and
Technology (CREST), Japan Science and Technology Agency (JST), Sakyo-ku, Kyoto 606-8502, Japan
(Received 26 January 2005)
Abstract. meso–meso, β−β, β−β Triply-linked zinc(II) porphyrin tapes were
synthesized by powerful oxidation of meso–meso-linked zinc(II) porphyrin arrays
up to tetramers with DDQ-Sc(OTf)3. Coordination of butylamine to zinc(II) ions of
porphyrin rings dissociates their aggregation, resulting in clear NMR spectra and
sharper red-shifted absorption bands.
INTRODUCTION
performed by the Grignard reagent to give 1-(4-bromo-
Discrete π-conjugated porphyrin arrays with extensive phenyl)-1-hydroxynonane (5), which was then iodi-
electronic delocalization are of interest as conducting nated with (Me)3SiCl and NaI, and reduced with NaBH4
organic materials, near-infrared dyes, nonlinear optical to 1-bromo-4-nonylbenzene (6).12 4-Nonylbenzal-
(NLO) materials, molecular devices, and so forth.1–3 dehyde (7) was obtained by formylation of 6 with
Along this line, a variety of porphyrin arrays that have butyllithium and then DMF. 5,15-Di(4-nonylphenyl)-
large inter-porphyrin conjugation have been extensively porphyrin 8 was synthesized from 7 and dipyrro-
exploited.4–11 One of the promising approaches is to methane in 30% yield. 8 was transformed into zinc
make multiple covalent linkages between porphyrins.7–11 complex 1a. 5,15-Di(4-nonylphenyl)-10-phenyl Zn(II)
Recently, we reported synthesis of meso–meso, β−β, porphyrin 1b was prepared from 8 with phenyllithium in
β−β triply-linked zinc(II) porphyrin tapes from corre- 79% yield.13 All these compounds were characterized by
sponding meso–meso singly-linked zinc(II) porphyrin means of 1H NMR, FAB MS, and UV-vis spectra.
arrays. The porphyrin tapes thus prepared exhibit
Triply-linked porphyrin dimer 2a was prepared by
unprecedented red-shifted absorption bands that reach direct oxidation of 10-capped-5,15-diarylporphyrins
into the infrared region. However, solubility of these 1b.14 The oxidation of 1b with 5 equivs of DDQ and
porphyrin tapes is quite low due to their self-assembling Sc(OTf)3 in refluxing toluene gave meso–meso, β−β,
nature by π−π stacking, hampering further characteriza- β−β triply-linked diporphyrin 2a in 76% yield. MALDI-
tion by means of 1H NMR and UV-vis absorption spec- TOF mass spectrum of 2a showed its parent peak at
tra. Here, we prepared triply-linked porphyrin arrays m/z = 1703 (calcd for C112H114N8Zn2 = 1703).
2–4 as shown in Scheme 1. Butylamine-induced disso-
The synthesis of higher oligomers was accomplished
ciation of porphyrin aggregate in solution was observed according to Scheme 3. The key oligomerization reaction
1
in H NMR and absorption spectra, which provided utilizes a random oxidative coupling of diaryl- and triaryl-
information on the original nature of porphyrin tapes.
derivatives, which effectively proceeded to form trimer
and tetramer. The yield of each product is acceptably high.
This approach also has the great advantage of the favorite
one-pot availability of homologues.
RESULTS AND DISCUSSION
AgI-promoted oxidation of a mixture of 1a and 1b (1:7)
*Authortowhomcorrespondenceshouldbeaddressed. E-mail:
osuka@kuchem.kyoto-u.ac.jp
Synthesis
The synthetic route of porphyrin monomer is shown
in Scheme 2. Alkylation of 4-bromobenzaldehyde was
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294
Scheme 1. Molecular structures.
gave meso–meso-linked porphyrin dimer (10), trimer substituents were introduced in 1c. AgI-promoted oxida-
(11a), and tetramer (12a) in 63% yield for 11a and 20% tive coupling reaction of 1c and 1b (1:7) was performed
yield for 12a based on 1a. The reaction mixture was easily to form meso–meso-linked porphyrin dimer (10), trimer
separated by GPC-HPLC. The DDQ-Sc(OTf)3 oxidation (11b), and tetramer (12b) in 64% yield for 11b and in
of 11a was performed in toluene at 100 ºC, which gave 15% yield for 12b based on 1c. The further oxidation of
meso–meso, β−β, β−β triply-linked triporphyrin 3a in 11b was performed with 7 equivs of DDQ and Sc(OTf)3
68% yield. The MALDI-TOF mass spectrum of 3a ap- in refluxing toluene, to gave triply-linked triporphyrin
peared at m/z = 2474 (calcd for C162H164N12Zn3, 2475).
3b in 67% yield. The molecular weight of 3b has been
The oxidation of 12a was attempted with 9 equivs of confirmed by MALDI-TOF mass spectrum (m/z = 2447,
DDQ and Sc(OTf)3 in refluxing toluene, which gave calcd for C160H160N12Zn3, 2446).
meso–meso, β−β, β−β triply-linked tetraporphyrin 4a in
The oxidation of 12b was attempted with 9 equivs of
63% yield. MALDI-TOF mass spectrum showed its DDQ and Sc(OTf)3 in refluxing toluene, which gave
peaks at m/z = 6390 and 9599 corresponding to dimeric triply-linked tetraporphyrin 4b in 61% yield. In contrast
and trimeric aggregates (calcd for 12a C212H208N16Zn4 = to 4a, MALDI-TOF mass spectrum showed its parent
3241), indicating that 4a tends to form quite strong peak (m/z = 3195, calcd for C212H214N16Zn4, 3191), indi-
aggregation.
cating that aggregation was suppressed by peripheral
In order to improve the above problem, more bulky bulky substituents.
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Scheme 2. Synthetic scheme of 1a and 1b.
1H NMR Spectra
the absence of butylamine in either CDCl3 or CD2Cl2,
The 1H NMR spectrum of 2a in CDCl3 showed quite reflecting a stronger assembling nature. Similar to the
broad peaks, while 2b showed sharper peaks, probably case of 2a, the 1H NMR spectra of 3a and 3b in CD2Cl2
due to steric effects of the meso-aryl substituents that become sharper with 5% butylamine, exhibiting the β-
suppress aggregation. Figure 1 illustrates the concentra- pyrrolic protons at 6.29, 6.97, 7.53, and 7.53 ppm, and
tion dependence of the 1H NMR spectra of 2a from 0.5 6.23, 6.97, 7.52, and 7.53 ppm, respectively (Fig. 2).
mM to 4.0 mM. The broad spectrum indicated aggrega-
tion in chloroform even at 0.5 mM concentration, and CD2Cl2 with 5% butylamine are shown in Fig. 3. The
The 1H NMR spectra of 1d, 2a, 3b, and 4b at 25 °C in
the spectrum as a whole was slightly high-field-shifted pyrrolic β-protons of the monomer 1d appear at 8.84
1
at 4.0 mM. Upon addition of butylamine, the H NMR (4H) and 8.87 (4H) ppm, while those of 2a appear at
spectrum of 2a became sharper, featuring signals of the high-field position (7.05 (4H) and 7.51 (8H) ppm). In
peripheral β-protons at 7.49, 7.48, and 7.02 ppm as a longer conjugated arrays 3b and 4b, the pyrrolic β-
pair of doublets and a singlet, and the aromatic protons protons are found at 7.53, 7.52, 6.97, and 6.23 ppm, and
of the meso-4-nonylphenyl groups at 7.62 and 7.32 as a 7.45, 7.45, 6.87, 6.29, and 6.23 ppm, respectively, again
pair of doublets, and the aromatic protons of the meso- indicating the high-field shifts compared with the corre-
phenyl groups at 7.71, 7.50, and 7.49 ppm. It has been sponding meso–meso singly-linked porphyrin arrays.
shown that aggregation of 2a is released in the presence The reason for these high-field shifts is not clear, but
of 5% butylamine in CDCl3, and the spectrum shown in one may suggest the weakened aromatic ring current
Fig. 1c is rather concentration independent.
due to the enhanced electronic communication between
1
The H NMR spectra of 3a and 3b were broader in neighboring porphyrins through the triple linkage.
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Scheme 3. Synthetic scheme of meso–meso-linked porphyrin arrays.
Fig. 1. 1H NMR spectra of 2a in CDCl3 at room temperature. (1) 0.5 mM, (2) 4.0 mM, (3) 4.0 mM with butylamine.
X-ray Crystal Structure of 2a Along With Two Axial
Butylamine Molecules
fashion. The X-ray structure shows the two porphyrin
rings are fused to form a coplanar saddle-like conforma-
The molecular structure of 2a with two butylamine tion with a mean plane deviation of 0.16 Å for the 25 core
molecules was confirmed by single-crystal X-ray diffrac- atoms. The crystal packing of 2a is like a parallel sheet
tion analysis (Fig. 4). Two butylamine molecules are coor- with an interporphyrin separation of approximately 9.3 Å,
dinated with the central zinc(II) ions of 2a in a trans featuring no significant aggregation in the solid state. The
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Fig. 2. 1H NMR spectra of 3a and 3b in CD2Cl2 at room temperature.
Fig. 3. 1H NMR spectra of 1d, 2a, 3b, and 4b in CD2Cl2 with 5% butylamine at room temperature.
newly formed two Cβ–Cβ bonds are both 1.44 Å, and the mers due to perpendicular conformation, triply-linked
bond length of Cmeso–Cmeso is 1.48 Å. X-ray structure of porphyrin arrays are fully conjugated over the whole
2b10 with ethanol exhibits a flat coplanar conformation with a array, which results in drastically red-shifted absorption
mean plane deviation (0.23 Å).
spectra that reach to the far-infrared region. The absorp-
tion spectra of triply-linked porphyrin arrays exhibit
three distinct broad absorption bands in CHCl3 (desig-
UV-vis Absorption Spectra
Although the electronic conjugation is almost dis- nated as bands I, II, III in Fig. 5a). Upon addition of 5%
rupted in the meso–meso singly-linked porphyrin oligo- butylamine, the absorption bands, especially bands II
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298
Fig. 4. X-ray structure of 2a with butylamine, top view (a) and side view (b). Displacements of the peripheral carbon atoms from
the mean plane of 24 atoms (c). Hydrogen atoms and butylamines are omittied for clarity in (a), and hydrogen atoms and 4-
nonylphenyl substituents are omitted for clarity in (b).
and III, become sharpened as a consequence of coordi- mains, but the low-energy Soret band II is sharpened
nation-induced dissociation.
and Q-band III is shifted to the low-energy side at 1813
In the case of 2a, two strong absorption bands, I and nm. These experiments revealed that very broad Q-
II, are observed at 420 and 583 nm, respectively, and a band-like lowest-energy absorptions of the porphyrin
broad band, III, at 1061 nm. Upon addition of buty- tapes are due to their aggregation, and disaggregation
lamine, the strong absorption bands remain nearly at the caused by the addition of coordinative butylamine led to
same position, but the Q-band-like absorption is shifted the sharpening of these bands with vibrational structures
to the low-energy side at 1146 nm, with distinct sharp- that are quite similar to those of porphyrin monomers.
ening and vibrational structures.
The molecular coefficient of the lowest energy absorp-
Essentially the same tendency was observed for 3b tion (band III) is steadily increased with the increase in
and 4b. Two strong Soret-like bands I and II, of 3b are the number of the porphyrins, reaching a value of
observed at 416 and 670 nm, respectively, and a broad 340,000 M–1cm–1 for 4b.
Q-band-like absorption III at 1290 nm in CHCl3. Upon
the addition of butylamine, the high-energy Soret band
remains at the same position, but the low-energy Soret
CONCLUSION
band is sharpened and Q-bands are shifted to the low- Triply-linked porphyrin arrays tend to aggregate exten-
energy side at 1494 nm. In the case of 4b, two strong sively due to their planar large π-conjugated framework.
1
Soret-like bands, I and II, are observed at 405 and Upon addition of butylamine, clear H NMR and UV-
776 nm, respectively, and a broad Q-band is observed at vis absorption spectra were observed for trimer and
1652 nm. Upon the addition of butylamine, band I re- tetramer, allowing the investigation on the intact elec-
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Fig. 5. UV-vis absorption spectra of 2a, 3b, and 4b in CHCl3 at room temperature. (a) Without butylamine. (b) With 5%
butylamine. The background absorbance at 6000 cm–1 may arise from the overtones of C–H vibration of CHCl3.
separations were performed by silica gel gravity column
chromatography (Wako gel C-300). Recycling preparative
GPC-HPLC was performed for separation of the porphyrin
oligomers (Japan Analytical Industry Co., LTD LC-908 with
JAI-GEL 2.5H and 3H column series with CHCl3 as an
eluent.).
tronic structure of porphyrin tapes. Further studies
about the photophysics of fully-conjugated porphyrin
tapes are currently under way.
EXPERIMENTAL
Synthesis
General Procedure
All reagents and solvents were of commercial reagent
1-(4-Bromophenyl)-1-hydroxynonane (5)
grade and were used without further purification except where
Octylmagnesium bromide was prepared from magnesium
1
noted. H NMR spectra were recorded on a JEOL delta- (2.44 g, 100 mmol) and 1-octylbromide (21.6 g, 100 mmol) in
600 spectrometer, and chemical shifts were reported as the diethyl ether at room temperature. Then, 1-bromobenzal-
delta scale in ppm relative to CH2Cl2 (δ 5.32 ppm) and CHCl3 dehyde (13.5 g, 80 mmol) was added to the mixture in diethyl
(δ 7.26 ppm). Spectroscopic grade CH2Cl2 was used as solvent ether at 0 ºC. The combined organic solution was washed with
for all spectroscopic studies. UV-vis absorption spectra were water, dried over anhydrous Na2SO4, and evaporated. The
recorded on a Shimadzu UV-3100 spectrometer. Mass spectra resulting yellow residue was taken up in hexane and purified
were recorded on a JEOL HX-110 spectrometer using the by silica gel chromatography with a mixture of hexane:
positive-FAB ionization method with accelerating voltage AcOEt, 3:1, as an eluent. The yield of 5 was 98% (29.2 g).
10 kV and a 3-nitrobenzylalcohol matrix. MALDI-TOF mass 1H NMR(CDCl3): δ = 0.87 (3H, t, J = 6.9 Hz), 1.24 (7H, m),
spectra were recorded on a Shimadzu/KRATOS KOMPACT 1.36 (2H, m), 1.66 (2H, m), 1.73 (2H, m), 1.99 (1H, s), 4.62
MALDI 4 spectrometer using a positive-MALDI-TOF (2H, m), 7.21 (2H, d, J = 8.0 Hz), and 7.45 (2H, d, J = 8.0 Hz);
method with/without a sinapinic acid matrix. Preparative FAB MS: calcd for C15H23BrO: 299.2; found: 299.2 [M+].
Ikeue et al. / Porphyrin Tapes

300
4-Bromophenylnonane (6)
The yield of 1a was 92% (200 mg). 1H NMR(CDCl3): δ = 0.94
A mixture of 5 (29.95 g, 0.1 mmol), trimethylsilylchloride (6H, t, J = 6.4 Hz), 1.32~1.45 (16H, m), 1.51 (4H, m), 1.59
(55.4 mL, 0.6 mol), and NaI (89.9 g, 0.6 mol) in CH3CN (4H, m), 1.95 (4H, m), 2.98 (4H, t, J = 7.8 Hz), 7.59 (4H, d, J
solution (300 mL) was stirred under N2 for 12 h at room = 7.4 Hz), 8.15 (4H, d, J = 7.4 Hz), 9.16 (4H, d, J = 4.1 Hz),
temperature. Then, the organic residue was washed with 9.41 (4H, d, J = 4.1 Hz), and 10.29 (2H, s); FAB MS: calcd for
Na2S2O3 solution, dried over anhydrous Na2SO4 and evapo- C50H56N4Zn: 776.4; found: 776.4 [M+]; UV (CHCl3): λmax
rated. The resulting orange residue was stirred with NaBH4 413 and 540 nm.
(5.7 g, 0.15 mol) in DMSO (300 mL) under N2 for 12 h at room
=
temperature. The mixture was extracted with hexane. Com-
bined organic extracts were dried over anhydrous Na2SO4 and
evaporated. The yellow residue was taken up in hexane and
purified by silica gel chromatography with hexane as an elu-
Zn (II) 5-15-Di(4-nonylphenyl)-10-phenylporphyrin 1b
and Zn (II) 5-15-di(4-nonylphenyl)-10,20-diphenyl-
porphyrin 1d
8 (157 mg, 0.22 mmol) was dissolved in dry THF (50 mL)
under N2 and the solution was cooled at 0 °C, to which PhLi
(1.4 mL, 1.5 M solution in ether) was added dropwise, and the
reaction flask was removed from the cooling bath and allowed
to warm to room temperature and stirred for 30 min. Then, the
reaction mixture was treated with 50% aqueous THF (1 mL).
DDQ (100 mg, 0.44 mmol as a CH2Cl2 solution) was added
and stirred for 15 min. The organic residue was washed with
water, dried over anhydrous Na2SO4, and evaporated. Then,
the product separation was performed on a preparative-size
exclusion column (recycling preparative GPC-HPLC) for 8,
5,15-di(4-nonylphenyl)-10-phenylporphyrin 9, and 5,15-di(4-
nonylphenyl)-10,20-diphenylporphyrin. A solution of 9 in
CHCl3 was stirred under N2 for 15 min at room temperature. A
saturated Zn(OAc)2 in CH3OH (3 mL) was added to the solu-
tion and it was stirred for 3 h at 60 °C. Then, the organic
solution was washed with water, dried over anhydrous
Na2SO4, and evaporated. The solid was taken up in CH2Cl2 and
purified by silica gel chromatography by CH2Cl2. The yield of
Zn(II) 5,15-di(4-nonylphenyl)-10-phenylporphyrin 1b was
79% (149 mg). A solution of 5,15-di(4-nonylphenyl)-10,20-
diphenylporphyrin in CHCl3 was stirred under N2 for 15 min at
room temperature. A saturated Zn(OAc)2 in CH3OH (3 mL)
was added to the solution and it was stirred for 3 h at 60 ºC.
Then, the residue was washed with water, dried over anhy-
drous Na2SO4, and evaporated. The solid was taken up in
CH2Cl2 and purified by silica gel chromatography by CH2Cl2.
The yield of Zn(II) 5,15-di(4-nonylphenyl)-10,20-diphenyl-
1
ent. The first band was 6 (21.52 g, 76%). H NMR(CDCl3):
δ = 0.89 (3H, t, J = 6.0 Hz), 1.28 (12H, m), 1.59 (2H, m), 2.55
(2H, m), and 7.05 (2H, d, J = 8.4 Hz), and 7.39 (2H, d, J = 8.4
Hz); FAB MS: calcd for C15H23Br: 282.2; found: 282.2 [M+].
4-Nonylbenzaldehyde (7)
To a solution of 4-bromophenylnonane (8.5 g, 30 mmol)
was added a hexane solution of butyllithium (57 mL,
92 mmol) in dry THF (200 mL) at –78 °C. After stirring at
–78 ºC for 1 h, DMF (6.1 mL, 92 mmol) was slowly added to
the mixture. After the reaction temperature was increased
gradually until room temperature, the mixture was poured into
iced water and extracted with hexane. The combined organic
extract was washed with water, dried over anhydrous Na2SO4,
and evaporated. The organic residue was taken up in hexane
and purified by silica gel chromatography with a mixture of
hexane: AcOEt, 3:1, as an eluent. The yield of 4-nonyl-
1
benzaldehyde was 93% (6.45 g). H NMR(CDCl3): δ = 0.85
(3H, t, J = 7.0 Hz), 1.22 (10H, m), 1.28 (2H, m), 1.61 (2H, m),
2.65 (2H, m), 7.29 (2H, d, J = 8 Hz), 7.65 (2H, d, J = 8.0 Hz),
and 9.93 (1H, s); FAB MS: calcd for C15H23BrO: 232.3; found:
232.3 [M+].
5-15-Di(4-nonylphenyl)porphyrin (8)
A solution of dipyrromethane (458 mg, 3.1 mmol) and 7
(630 mg, 3.1 mmol) in dry CH2Cl2 (600 mL) was stirred under
N2 for 15 min. TFA (0.13 mL, 2.0 mmol) was added to the
solution via syringe, the flask was shielded from light, and the
solution was stirred for 3 h at room temperature. DDQ (1.15g,
5 mmol) was added, and the solution was stirred for an addi-
tional 2 h. The mixture was passed directly through an alumina
column and evaporated. The yield of 8 was 30% (668 mg).
1H NMR(CDCl3): δ = –3.09 (2H, s), 0.94 (6H, t, J = 6.6 Hz),
1.36 (16H, m), 1.52 (4H, m), 1.59 (4H, m), 1.94 (4H, m), 2.97
(4H, t, J = 7.3 Hz), 7.61 (4H, d, J = 7.6 H), 8.17 (4H, d, J =
7.6 Hz), 9.11 (4H, d, J = 2.3 Hz) 9.38 (4H, d, J =
2.3 Hz), and 10.29 (2H, s); FAB MS: calcd for C50H58N4:
715.5; found: 715.5 [M+]; UV (CHCl3): λmax = 409, 503, 538,
576, and 630 nm.
1
porphyrin 1d was 5.4% (11 mg). 1b: H NMR(CDCl3): δ =
0.94 (6H, t, J = 6.9 Hz), 1.36–1.42 (16H, m), 1.51 (4H, m),
1.59 (4H, m), 1.95 (4H, m), 2.98 (4H, t, J = 7.8 Hz), 7.57 (4H,
d, J = 7.3 Hz), 7.74 (2H, m), 7.77 (1H, m), 8.14 (4H, d, J =
7.8 Hz), 8.21 (2H, d, J = 6.5 Hz), 8.96 (2H, d, J = 4.6 Hz),
9.02 (2H, d, J = 4.2 Hz), 9.12 (2H, d, J = 4.6 Hz), 9.37 (2H, d,
J = 4.6 Hz), and 10.22 (1H, s); FAB MS: calcd for C56H60N4Zn:
852.5; found: 852.5 [M+]; UV (CHCl3): λmax = 417 and
1
545 nm. 1d: H NMR(CDCl3): δ = 0.91 (6H, t, J = 6.4Hz),
1.33–1.42 (16H, m), 1.47 (4H, m), 1.56 (4H, m), 1.92 (4H, m),
2.95 (4H, t, J = 7.8 Hz), 7.54 (4H, d, J = 7.8 H), 7.74 (4H m),
7.75 (2H m), 8.10 (4H, d, J = 7.9 Hz), 8.21 (4H, m), 8.92 (4H,
d, J = 4.6 Hz), 8.96 (4H, d, J = 4.6 Hz); FAB MS: calcd for
Zn (II) 5-15-Di(4-nonylphenyl)porphyrin 1a
C62H64N4Zn: 928.5; found: 928.5 [M+]; UV (CHCl3): λmax
=
A saturated solution of Zn(OAc)2 in CH3OH (3 mL) was
added to a solution of 8 (200 mg, 0.28 mmol) in CHCl3
(150 mL) and the resulting mixture was stirred for 3 h at 60 ºC.
Then, the organic residue was washed with water, dried over
anhydrous Na2SO4, and evaporated. The solid was taken up in
CH2Cl2 and purified by silica gel chromatography by CH2Cl2.
1
422.5 and 552.5 nm. 1d with butylamine: H NMR(CDCl3):
δ = 0.94 (6H, t, J = 6.9Hz), 1.35–1.45 (16H, m), 1.49 (4H, m),
1.58 (4H, m), 1.93 (4H, m), 2.95 (4H, t, J = 7.8 Hz), 7.56 (4H,
d, J = 7.6 Hz), 7.74 (4H, m), 7.76 (2H, m), 8.14 (4H, d, J =
7.8 Hz), 8.22 (2H, d, J = 6.5 Hz), 8.84 (4H, d, J = 4.6 Hz), and
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8.87 (2H, d, J = 4.6 Hz); UV (CHCl3): λmax = 430, 565, and
606 nm.
meso–meso Singly-linked Zn(II) tri- and tetraporphyrin
11b and 12b
1c (30 mg, 0.039 mmol) and 1b (240 mg, 0.281 mmol)
were dissolved in CHCl3 (200 mL), and the reaction vessel
was covered with foil. A solution of 0.1 M AgPF6 in CH3CN
(0.24 mmol) was added all at once. After stirring for 12 h, the
mixture was diluted with water and the porphyrin products
were extracted with CHCl3. The combined organic extract was
washed with water and dried over anhydrous Na2SO4. Then,
recycling preparative GPC-HPLC afforded three major frac-
tions that eluted in the following order: 10 (171 mg, 0.100
mmol), 11b (61.2 mg, 0.025 mmol), and 12b (9.6 mg, 0.003
meso–meso, β–β, β–β Triply-linked Zn(II)-diporphyrin 2a
1b (100 mg, 0.118 mmol) was oxidized with DDQ (133.9
mg, 0.59 mmol) and Sc(OTf)3 (253 mg, 0.59 mmol) in toluene
at 60 ºC for 30 min under N2. After addition of THF to the
mixture, the resulting solution was directly passed through an
alumina column and then evaporated. The yield of 2a was
86%. 2a; MALDI-TOF MS: calcd for C112H116N8Zn2: 1705;
found: 1703; UV (CHCl3): λmax(ε) = 420 (174000), 562
(136000), 583 (144000), and 1061 (39600) nm. 2a with buty-
lamine; 1H NMR (CD2Cl2): δ = 0.92 (12H, t, J = 6.7 Hz), 1.20–
1.35 (16H, m), 1.44 (8H, m), 1.50 (8H, m), 1.80 (8H, m), 2.81
(8H, t, J = 7.6 Hz), 7.05 (4H, s), 7.36 (8H, d, J = 7.8 Hz), 7.51
(8H, s), 7.55 (2H, m), 7.55 (4H, m), 7.65 (8H, d, J = 7.8 Hz),
and 7.75 (8H, m); UV (CHCl3): λmax(ε) = 425 (173000), 563
(143000), and 1146 (44400) nm.
1
mmol). 11b: H NMR(CDCl3): δ 0.85 (12H, t, J = 6.9 Hz),
1.20–1.35 (32H, m), 1.41 (8H, m), 1.49 (8H, m), 1.53 (36H, s),
1.83 (8H, m), 2.87 (8H, t, J = 7.8 Hz), 7.48 (8H, d, J = 8.3 Hz),
7.58 (2H, t, J = 1.8 Hz), 7.81 (4H, m), 7.82 (4H, m), 8.07 (4H,
d, J = 1.8 Hz), 8.14 (8H, d, J = 8.3 Hz), 8.16 (4H, d, J = 4.6
Hz), 8.24 (4H, d, J = 4.6 Hz), 8.31 (4H, d, J = 7.7 Hz), 8.72
(4H, d, J = 4.5 Hz), 8.75 (4H, d, J = 4.5 Hz), 9.01 (4H, d, J =
4.6 Hz), and 9.03 (4H, d, J = 4.6 Hz). MADLI-TOF MS: calcd
meso–meso Singly-linked Zn(II) di-, tri-, and tetra-
porphyrin 10, 11a, and 12a
for C160H168N12Zn3: 2455; found: 2453; UV (CHCl3): λmax
=
1a (40 mg, 0.051 mmol) and 1b (320 mg, 0.374 mmol)
were dissolved in CHCl3 (200 mL), and the reaction vessel
was covered with foil. A solution of 0.1 M AgPF6 in CH3CN
(0.24 mmol) was added all at once. After stirring for 12 h, the
mixture was diluted with water and the porphyrin products
were extracted with CHCl3. The combined organic extract was
washed with water and dried over anhydrous Na2SO4. Then,
separation by recycling preparative GPC-HPLC afforded
three major fractions that eluted in the following order: 10
(216.3 mg, 0.12 mmol), 11a (79.4 mg, 0.032 mmol), and 12a
(16.7 mg, 0.005 mmol). 10: 1H NMR (CDCl3): δ = 0.81 (12H,
t, J = 6.9 Hz), 1.2–1.3 (32H, m), 1.35 (8H, m), 1.44 (8H, m),
1.79 (8H, m), 2.92 (8H, t, J = 7.3 Hz), 7.45 (8H, d, J = 7.8 Hz),
7.79 (4H, m), 7.80 (2H, m), 8.07 (4H, d, J = 4.5 Hz), 8.08 (8H,
d, J = 7.8 Hz), 8.29 (4H, m), 8.66 (4H, d, J = 4.5 Hz), and 8.98
(8H, s); MALDI-TOF MS: calcd for C112H118N8Zn2: 1707;
found: 1707; UV (CHCl3): λmax = 422, 458, and 563 nm. 11a:
1H NMR (CDCl3): δ = 0.75 (6H, t, J = 6.9 Hz), 0.88 (12H, t,
J = 6.9 Hz), 1.16–1.39 (60H, m), 1.41 (4H, m), 1.49 (8H, m),
1.72 (4H, m), 1.85 (8H, m), 2.76 (4H, t, J = 7.4 Hz), 2.89 (8H,
t, J = 7.4 Hz), 7.37 (4H, d, J = 8.3 Hz), 7.49 (8H, d, J = 8.3 Hz),
7.81 (2H, m), 7.82 (4H, m), 8.12 (4H, d, J = 8.7 Hz), 8.16 (8H,
d, J = 7.4 Hz), 8,18 (4H, d, J = 4.6 Hz), 8.23 (4H, d, J = 4.6
Hz), 8.31 (4H, m), 8.73 (4H, d, J = 4.6 Hz), 8.75 (4H, d, J = 4.6
Hz), 9.02 (4H, d, J = 4.6 Hz), and 9.04 (4H, d, J = 4.6 Hz);
MALDI-TOF MS: calcd for C162H172N12Zn3: 2483; found:
2480; UV (CHCl3): λmax = 419, 479, and 571 nm. 12a:
1H NMR (CDCl3): δ = 0.76 (12H, t, J = 6.9 Hz), 0.86 (12H, t, J
= 6.9 Hz), 1.16–1.36 (80H, m), 1.38 (8H, m), 1.49 (8H, m),
1.74 (4H, m), 1.85 (8H, m), 2.77 (4H, t, J = 7.3 Hz), 2.88 (8H,
418, 477, and 567 nm. 12b: 1H NMR(CDCl3): δ 0.85 (12H, t,
J = 7.3 Hz), 1.2–1.35 (32H, m), 1.38 (72H, s), 1.39 (8H, m),
1.49 (8H, m), 1.84 (8H, m), 2.88 (8H, t, J = 7.8 Hz), 7.50 (8H,
d, J = 8.3 Hz), 7.62 (4H, t, J = 1.9 Hz), 7.81(4H, m), 7.82 (4H,
m), 8.11 (8H, d, J = 1.9 Hz), 8.16 (8H, d, J = 8.3 Hz), 8.19 (4H,
d, J = 4.6 Hz), 8.27 (4H, d, J = 4.6 Hz), 8.32 (4H, d, J =
4.6 Hz), 8.33 (4H, m), 8.74 (4H, d, J = 4.6 Hz), 8.77 (4H, d,
J = 4.6 Hz), 8.80 (4H, d, J = 4.6 Hz), 9.03 (4H, d, J = 4.6 Hz),
and 9.50 (4H, d, J = 4.6 Hz). MALDI-TOF MS: calcd for
C208H218N16Zn4: 3204; found: 3196; UV (CHCl3): λmax = 418,
487, and 574 nm.
meso–meso, β–β, β–β Triply-linked Zn(II)-triporphyrin 3a
11a (19.6 mg, 0.008 mmol) was oxidized with DDQ (12.7
mg, 0.056 mmol) and Sc(OTf)3 (24.0 mg, 0.056 mmol) in tolu-
ene at 110 ºC for 20 min under N2. The mixture was directly
passed through an alumina column and evaporated. The yield of
3a was 68% (13.6 mg). 3a: MALDI-TOF MS: calcd for
C162H164N12Zn3: 2475; found: 2474; UV (CH2Cl2): λmax = 417,
667, and 1304 nm. 3a with butylamine: 1H NMR(CD2Cl2): δ =
0.84 (6H, t, J = 6.9 Hz), 0.91 (12H, t, J = 6.9 Hz), 1.16–1.39
(60H, mp), 1.40 (4H, m), 1.48 (8H, m), 1.75 (4H, m), 1.77 (8H,
m), 2.72 (4H, t, J = 7.8 Hz), 2.77 (8H, t, J = 7.8Hz), 6.29 (4H, s),
6.97 (4H, s), 7.24 (4H, d, J = 7.8 Hz), 7.31 (8H, d, J = 7.8 Hz),
7.37 (4H, d, J = 7.8 Hz), 7.53 (4H, m-Ph, m), 7.53 (2H, p-Ph, m),
7.53 (4H, s), 7,53 (4H, s), 7.58 (8H, d, J = 7.8 Hz), and 7.72 (4H,
o-Ph, m); UV (CHCl3): λmax = 427, 680, and 1491 nm.
meso–meso, β–β, β–β Triply-linked Zn(II)-triporphyrin 3b
11b (20.0 mg, 0.008 mmol) was oxidized with DDQ
t, J =7.4 Hz), 7.40 (8H, d, J = 7.8 Hz), 7.50 (8H, d, J = 8.3 Hz), (12.7 mg, 0.056 mmol) and Sc(OTf)3 (24.0 mg, 0.056 mmol)
7.80 (2H, m), 7.81 (4H, m), 8.14 (8H, d, J = 7.4 Hz), 8.17 (8H, in toluene at 110 ºC for 30 min under N2. The mixture was
d, J = 7.4 Hz), 8,18 (4H, d, J = 4.6 Hz), 8.23 (4H, d, J = directly passed through an alumina column and evaporated.
4.6 Hz), 8.28 (4H, d, J = 4.6 Hz), 8.31 (4H, m), 8.75 (4H, d, The yield of meso–meso β−β, β−β triply-linked Zn(II)-
J = 4.6Hz), 8.76(4H, d, J = 4.6Hz), 8.79 (4H, d, J = 4.6Hz), diporphyrin was 67% (13.3 mg). MALDI-TOF MS: calcd for
9.02 (4H, d, J = 4.6Hz), and 9.04 (4H, d, J = 4.6 Hz); MALDI- C160H160N12Zn3: 2447; found: 2446; UV (CHCl3): λmax(ε) = 416
TOF MS: calcd for C212H226N16Zn4: 3259; found: 3256; UV (128000), 670 (133000), and 1290 (54000) nm. 3b with buty-
(CHCl3): λmax = 418, 489, and 575 nm.
lamine: 1H NMR (CD2Cl2): δ = 0.89 (12H, t, J = 6.9 Hz), 1.15–
Ikeue et al. / Porphyrin Tapes

302
1.25 (32H, m), 1.30 (36H, s), 1.38 (8H, m), 1.44 (8H, m), 1.73
(8H, m), 2.74 (8H, t, J = 7.8 Hz), 6.23 (4H, s), 6.97 (4H, s),
7.23 (8H, d, J = 7.8 Hz), 7.31 (4H, d, J = 1.8 Hz), 7.49 (2H, t,
J = 1.8 Hz), 7.51 (4H, m), 7.52 (2H, m), 7.52 (4H, s), 7.53 (4H,
s), 7.58 (8H, d, J = 7.8 Hz), and 7.71 (4H, m); UV (CHCl3):
Chem. Int. Ed. 1999, 38, 1351.
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Science 1999, 286, 1550. (b) Joachim, C.; Gimzewski,
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Kluwer Academic Publishers: Dordrecht, 1995; Vol.
289, pp 285–320.
(4) (a) Arnold, D.P.; Johnson, A.W.; Mahendran, M. J.
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D.P.; Heath, G.A.; James, D.A. J. Porphyrins
Phthalocyanines 1999, 3, 5.
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λ
max(ε) = 431 (146000), 680 (202000), 1249 (32000), and 1494
(170000) nm.
meso–meso, β–β, β–β Triply-linked Zn(II) tetraporphyrin 4a
12a (15 mg, 0.0046 mmol) was oxidized with DDQ
(9.4 mg, 0.041 mmol) and Sc(OTf)3 (17.8 mg, 0.041 mmol) in
toluene at 110 ºC for 20 min under N2. The mixture was passed
directly through an alumina column and evaporated. The yield
of meso–meso, β−β, β−β triply-linked Zn(II)-diporphyrin was
63% (9.5 mg). UV (CHCl3): λmax = 403, 777, and 1632 nm. 4a
with butylamine: UV (CH2Cl2): λmax = 427, 738, and 1808 nm.
(6) (a) Anderson, H.L. Inorg. Chem. 1994, 33, 972. (b) Tay-
lor, P.N.; Huuskonen, J.; Rumbles, G.; Aplin, R.T.; Will-
iams, E.; Anderson, H.L. Chem. Commun. 1998, 909.
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Reimers, J.R.; Lu, T.X.; Crossley, M.J.; Hush, N.S.
Chem. Phys. Lett. 1996, 256, 353.
meso–meso, β–β, β–β Triply-linked Zn(II) tetraporphyrin 4b
12b (12 mg, 0.0046 mmol) was oxidized with DDQ (9.4
mg, 0.041 mmol) and Sc(OTf)3 (17.8 mg, 0.041 mmol) in
toluene at 110 ºC for 20 min under N2. The mixture was passed
directly through an alumina column and evaporated. The yield
of meso–meso, β−β, β−β triply-linked Zn(II)-diporphyrin was
61% (8.5 mg). MALDI-TOF MS: calcd for C212H214N16Zn4:
3191; found: 3195; UV (CHCl3): λmax = 405 (117000), 776
(190000), and 1652 (111000) nm. 4b with butylamine:
1H NMR (CD2Cl2): δ = 0.89–1.40 (124H), 1.44 (8H, m), 1.72
(8H, m), 2.74 (8H, t, J = 7.5Hz), 6.23 (4H, s), 6.29 (4H, s),
6.87 (4H, s), 7.28 (8H, d, J = 7.3 Hz), 7.28 (8H, d, J = 1.4 Hz),
7.45 (4H, s), 7.45 (4H, s), 7.46 (4H, t, J = 1.8 Hz), 7.51 (4H,
m), 7.52 (2H, m), 7.55 (8H, d, J = 7.3 Hz), and 7.69 (4H, m);
UV (CHCl3): λmax(ε) = 429 (160000), 734 (317000), and 1813
(340000) nm.
(8) (a) Kobayashi, N.; Numao, M.; Kondo, R.; Nakajima,
S.; Osa, T. Inorg. Chem. 1991, 30, 2241.
(9) (a) Vicente, M.G.H.; Jaquinod, L.; Smith, K.M. Chem.
Commun. 1997, 177. (b) Jaquinod, L.; Siei, O.; Khoury,
R.G.; Smith, K.M. Chem. Commun. 1998, 1261. (c)
Vicente, M.G.H.; Cancilla, M.T.; Lebrilla, C.B.; Smith,
K.M. Chem. Commun. 1998, 2355. (d) Paoloesse, R.;
Jaquinod, L.; Sala, F.D.; Nurco, D.J.; Prodi, L.; Natale,
C.D.; D’Amico, A.; Carlo, A.D.; Lugli, P.; Smith, K.M.
J. Am. Chem. Soc. 2000, 122, 11295. (e) Aihara, H.;
Jaquinod, L.; Nurrco, D.J.; Smith, K.M. Angew. Chem.
Int. Ed. 2001, 40, 3439.
(10) (a) Tsuda, A.; Nakano, A.; Furuta, H.; Yamochi, H.;
Osuka, A. Angew. Chem. Int. Ed. 2001, 40, 3439. (b)
Tsuda, A.; Furuta, H.; Osuka, A. Angew. Chem. Int. Ed.
2000, 39, 2549. (c) Tsuda, A.; Furuta, H.; Osuka, A. J.
Am. Chem. Soc. 2001, 123, 10304.
Crystallographic data: C120H132N10Zn2, MW = 1845.10, tri-
clinic, space group P-1 (no. 2), a = 11.9423(14), b =
13.6104(16), c = 16.6785(19) Å, α = 103.596(2) β =
93.325(2), γ = 111.574(2)º, V = 2418.9(5) Å3, Z = 1, ρcalcd
=
1.267 g/cm3, T = –150 ºC, 14257 measured reflections, 10218
unique reflections (Rint = 0.057). R = 0.0587, Rw = 0.1608 (all
data), GOF = 0.979. CCDC-261532 contains the supplemen-
tary crystallographic data for this paper. These data can be
obtained free of charge via www.ccdc.cam.ac.uk/conts/
retrieving.html (or from the Cambridge Crystallographic Data
Centre, 12 Union Road, Cambridge CB21EZ, UK; fax:
(+44)1223-336-033; or deposite@ccdc.cam.ac.uk).
(11) (a) Tsuda, A.; Osuka, A. Science 2001, 293, 79. (b)
Tsuda, A.; Osuka. A. Adv. Mater. 2002, 14, 75.
(12) Franks, S.; Hartley, F.R. J. Chem. Soc., Perkin Trans. 1
1980, 2233.
(13) Senge M.O.; Feng, X. J. Chem. Soc., Perkin Trans. 1
2001, 1030.
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Israel Journal of Chemistry
45
2005