Synthesis of doubly strapped meso-meso-linked porphyrin arrays and triply linked conjugated porphyrin tapes

Article abstract of DOI:10.1002/ejoc.200600289

1,10-Dioxydecamethylene doubly strapped Zn^II-porphyrin S1 was prepared and treated with AgPF₆ to give meso-meso-linked porphyrin oligomers Sn (n = 2, 3, 4, 6, 8, and 12), which were converted to triply linked porphyrin tapes TSn by m

Full text of DOI:10.1002/ejoc.200600289

FULL PAPER
DOI: 10.1002/ejoc.200600289
Synthesis of Doubly Strapped meso–meso-Linked Porphyrin Arrays and Triply
Linked Conjugated Porphyrin Tapes
Toshiaki Ikeda,[a] Juha M. Lintuluoto,[a] Naoki Aratani,[a] Zin Seok Yoon,[b]
Dongho Kim,*[b] and Atsuhiro Osuka*[a]
Keywords: Conjugation / Encapsulation / Molecular wires / Oligomerization / Porphyrinoids
1,10-Dioxydecamethylene doubly strapped ZnII-porphyrin
S1 was prepared and treated with AgPF6 to give meso–meso-
linked porphyrin oligomers Sn (n = 2, 3, 4, 6, 8, and 12),
which were converted to triply linked porphyrin tapes TSn
by meso,mesoЈ-dibromo meso–meso-linked porphyrin arrays
BSn and meso,mesoЈ-diphenyl meso–meso-linked porphyrin
bands. Low energy Q-band-like absorption bands of TSn are
progressively red-shifted with an increase in the number of
porphyrins without saturation behavior of conjugation. The
double straps suppress π–π stacking to some extent as seen
from partial preservation of vibration structures in the Q-
band-like bands of TS4 and TS6 and improve the chemical
arrays PSn. The structures of S1 and S2 have been deter- stabilities of longer tapes such as TS8 and TS12.
mined by single-crystal X-ray diffraction analysis. Character-
istically, Sn exhibit sharp Q(0,0) absorption and fluorescence
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2006)
Porphyrin, a tetrapyrrolic pigment with 18π-electron
conjugated system, has been used in a variety of fields in-
cluding reaction catalysts, artificial photosynthesis, photo-
dynamic therapy, sensors, and so on.[4] Electronic properties
of porphyrins are susceptible to chemical modifications at
the periphery. This characteristics has been used, through
the attachments of unsaturated segments to a porphyrinic π
network, to create conjugated porphyrins that exhibit rather
altered optical and electrochemical properties.[5–10] Re-
cently, we have explored meso–meso, β-β, β-β triply linked
porphyrin arrays (porphyrin tapes),[11] which are unprece-
dented in respect of the extend of π conjugation, in that
their absorption spectra exhibit the progressive red-shifts,
reaching an exceptionally red-shifted absorption band at
2800 nm for the dodecameric porphyrin tape.[11d] This fea-
ture is intriguing, since they do not exhibit a saturation be-
havior up to the dodecamer, indicating that ECL of these
arrays is at least larger than 12. Thus, this direct triple link-
age may serve as an effective platform to overcome the ECL
Introduction
Organic molecules with extended π-conjugated systems
have attracted considerable interest because of their possible
applications to organic conducting materials, non-linear op-
tical (NLO) materials, near-infrared (near-IR) dyes, and
molecular wires.[1,2] Extensive synthetic efforts have been
made towards such conjugated molecular systems, but have
often encountered serious problems such as synthetic diffi-
culty, chemical instability, and poor solubility with increas-
ing size of π-conjugated systems. Besides these, there is an
intrinsic problem of saturation as characterized by effective
conjugated length “ECL”. ECL defines the extent of π-con-
jugated systems in which the electronic delocalization is lim-
ited, and at which point the optical, electrochemical, and
other physical properties reach a saturation level that is
common with the analogous polymer.[1a,3] Therefore, it is
important to circumvent the ECL problem, particularly for
exploration of highly conjugated molecules that may serve
as molecular wires.
problem. In addition, the triply linked porphyrin tapes have
[12]
been used for functional conjugates with C60
and inter-
esting supramolecular interactions by taking advantages of
their unique electronic properties.[13] Despite these prom-
ises, the porphyrin tapes have problems of poor solubility,
strong stacking tendency, and chemical instability, which
become more serious with increasing number of porphyrin
subunits.
In this paper, we report the synthesis of doubly strapped
porphyrin tapes, which has been designed to increase chem-
ical stability and improve solubility in common organic sol-
vents. In recent years, similar encapsulating strategy has
been demonstrated to be effective for the isolation of molec-
[a] 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
Fax: +81-75-753-3970
E-mail: osuka@kuchem.kyoto-u.ac.jp
[b] Center for Ultrafast Optical Characteristics Control and De-
partment of Chemistry, Yonsei University,
Seoul 120-749, Korea
Fax: +82-2-2123-2434
E-mail: dongho@yonsei.ac.kr
Supporting information for this article is available on the
WWW under http://www.eurjoc.org or from the author.
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T. Ikeda, J. M. Lintuluoto, N. Aratani, Z. S. Yoon, D. Kim, A. Osuka
FULL PAPER
ular wires, which then acquire improved solubilities as well phyrin ring is covered by the two 1,10-dioxydecamethylene
as enhanced emission quantum yields.[14]
straps that take an anti-staggered conformation with an
average separation of 4.1 Å from the porphyrin plane (Fig-
ure 2). In the crystal, the distance between the nearest two
porphyrins is about 7.91 Å without any significant intermo-
Results and Discussions
The doubly strapped porphyrin S1 was synthesized as lecular π–π interaction.
shown in Scheme 1. 2,6-Dimethoxy-4-tridecylbenzaldehyde
AgI-promoted meso–meso coupling reaction is usually
(4) was prepared from commercially available 3,5-dimeth- conducted by treatment of a 5,15-diaryl-ZnII-porphyrin
oxybenzaldehyde (1) in 35% yield in three steps. Acid-cata- with a slightly excess amount of AgPF6 in CHCl3 at room
lyzed condensation of the aldehyde 4 and the dipyrrome- temperature for several hours (Scheme 2).[16] We first tried
thane (5) followed by DDQ oxidation provided 5,15-bis(2,6- the coupling reaction of S1 under the standard conditions
dimethoxy-4-tridecylphenyl)porphyrin (6) in 30% yield. De- (1.5 equiv. of AgPF6 and at 30 °C), which however did not
methylation of 6 with BBr3 followed by ZnII-ion insertion provide any coupling product. In contrast, under the same
gave the porphyrin 7 in 98% yield in two steps. Double- conditions, the coupling reaction of M1 that is a strap-free
strapping reaction of 7 with 1,10-dibromodecane was car- analogue of S1 proceeded extensively to provide highly
ried out in acetone in the presence of K2CO3 under reflux oligomerized products within 1 h. At lower temperature
for 20 days[15] to give S1 in 62% yield. Doubly strapped (0 °C), the coupling reaction of M1 gave meso–meso-linked
porphyrin S1 exhibited the parent molecular ion peak at porphyrin dimer M2 (14%), trimer M3 (22%), tetramer M4
m/z = 1229.77 (calcd. for C78H109N4O4Zn, 1229.77) in the (10%), pentamer M5 (6%), hexamer M6 (4%), and hep-
ESI-TOF mass spectrum. The 600-MHz 1H NMR spec- tamer M7 (trace) along with recovery of M1 (28%) in a
trum of S1 in CDCl3 exhibited a singlet for Hmeso at δ = cleaner manner. Since this coupling reaction is believed to
10.22 ppm, a set of mutually coupled doublets for the pe- be initiated by the one-electron oxidation of a porphyrin by
1
2
ripheral β-protons Hβ and Hβ at δ = 9.37 and 9.11 ppm, AgI ion,[16] the first one-electron oxidation potential of the
and a singlet for Haryl at δ = 6.98 ppm (proton designations porphyrin should be an important parameter. Cyclic vol-
are shown in Figure 1). Characteristically, the protons of tammetry has revealed that the oxidation potential of S1 is
the strap alkyl chain were observed in a shielded region; Ha 0.29 V vs. ferrocene/ferrocenium ion, which is lower than
at δ = 3.75 ppm, Hb at δ = 0.65 ppm, Hc at δ = –1.34 ppm, that (0.32 V) of M1. Thus, the observed low reactivity of
Hd at δ = –1.44 ppm and He at δ = –2.48 ppm due to the S1 is considered to be not an electronic but a steric reason.
aromatic ring current of the porphyrin, hence indicating the Probably, steric hindrance imposed by the double straps
location of the straps just above the porphyrin ring.
The molecular structure of S1 was confirmed by X-ray in S1.
suppresses the approach of AgI ion to the porphyrin plane
crystallography. X-ray-quality crystals of S1 were obtained
We thus examined the coupling reaction of S1 under
by slow diffusion of acetonitrile into a CHCl3 solution of stronger conditions by changing the amount of AgPF6, re-
S1. The structure of S1 shows an almost symmetric confor- action temperature, and reaction time. In the meanwhile, we
mation with respect to the porphyrin plane, where the por- found that the coupling reaction of S1 in CHCl3 proceeded
Scheme 1. Synthesis of S1. a) C12H25MgBr, Et2O, 92%. b) NaBH3CN, TFA, CH2Cl2, 71%. c) 1) BuLi, Et2O, 2) DMF, 62%. d) 1) TFA,
CH2Cl2, 2) DDQ, 30%. e) 1) BBr3, CH2Cl2, 2) Zn(OAc)2·2H2O, MeOH, 98%. f) Br-(CH2)10-Br, K2CO3, acetone, 62%.
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Figure 1. Structures of porphyrins studied in this paper and proton designations.
at reflux in the presence of 4 equiv. of AgPF6 for 2 days. perature in the presence of AgI salt, under which conditions
Under these conditions, the coupling reaction of S1 pro- the longer Sn may be not tolerant. This situation makes
vided doubly strapped meso–meso-linked porphyrin dimer elongation of Sn to long porphyrin arrays quite a difficult
S2 (21%), trimer S3 (3%), and tetramer S4 (trace) along task, which is different from the previously reported non-
with recovery of S1 (52%). The similar reaction of S2 af- strapped series.[16]
forded S4 (21%), S6 (4%), and S8 (trace) along with recov-
The meso–meso-linked oligomers Sn thus prepared have
1
ery of S2 (57%). However, the similar reaction for S4 gave been characterized by H NMR, MALDI-TOF mass, UV/
only a small amount of S8 (2%) along with recovery of S4 Vis absorption, and fluorescence spectroscopy. MALDI-
(32%). The poor material balance suggested that S4 and TOF mass spectrometry was very effective for the detection
its coupling arrays might be unstable under these reaction of the parent molecular ion peaks of Sn at the expected
conditions. Lowering the reaction temperature to 45 °C led positions. The 1H NMR spectrum of S2 in CDCl3 provided
to better yields; S8 (10%), S12 (5%), and S16 (trace) along a singlet at δ = 10.25 ppm for Hmeso, two sets of mutually
with recovery (33%) of S4. The coupling of the doubly coupled doublets for Hβ1 and Hβ2 at δ = 9.40 and 9.10 ppm,
3
4
strapped ZnII porphyrin substrates Sn needs elevated tem- and for Hβ and Hβ at δ = 8.64 and 8.05 ppm, a singlet at
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FULL PAPER
Figure 2. X-ray crystal structure of S1. a) Top view, b) side view, and c) crystal packing pattern. Some atoms were omitted for clarity.
Scheme 2. AgI-promoted meso–meso coupling reaction of a 5,15-diaryl-substituted ZnII porphyrins.
δ = 6.89 ppm for Haryl, a series of multiplets at δ = 3.75 ppm gioselective meso,mesoЈ-dibromination to afford BSn (82–
for Ha protons, at δ = 0.77 ppm for Hb proton, at δ = 96%), which in turn were converted to meso,mesoЈ-di-
–1.01 ppm for Hc proton, at δ = –1.25 ppm for Hd proton, phenyl-capped arrays PSn through Suzuki–Miyaura cross
and at –2.17 ppm for He protons. The protons of the straps coupling with phenyl boronic acid (78–94%). The 1H NMR
were observed essentially at the same chemical shifts as spectrum of S4 exhibits a singlet at δ = 10.29 ppm due to
those of S1 except for slight down-field shifts for Ha, Hb, Hmeso and mutually coupled doublets at δ = 9.44 and 9.15
1
2
and Hc due to the ring current of neighboring porphyrin, ppm due to Hβ and Hβ protons, while that of BS4 lacks
implying that the aromatic ring current of the porphyrin singlet signal due to Hmeso and shows doublets at δ = 9.81
1
2
monomer S1 is well preserved in S2. Similar trends were and 9.05 ppm due to Hβ and Hβ that are down-field
observed for higher oligomers Sn. shifted due to the bromine atoms attached at the meso posi-
1
1
X-ray-grade crystals of S2 were grown by vapor diffusion tions. In the H NMR spectrum of PS4, signals due to Hβ
of acetonitrile into its CH2Cl2 solution. The solid-state and Hβ2 protons appear at δ = 8.97 and 8.96 ppm, reflecting
structure determined with these crystals shows that the two a local deshielding effect of the phenyl group at the meso
straps, similar to the case of S1, are lying over and below positions. The protons of the strapped chains in BSn and
the porphyrin macrocycle with an average 4.0 Å separation PSn appear at nearly the same positions as those in Sn.
from the porphyrin ring and a dihedral angle between two
The oxidation of PSn with DDQ-Sc(OTf)3 in toluene at
porphyrin planes of 70.3° (Figure 3, a, b). This small dihe- 80 °C for 2 h provided doubly strapped triply linked por-
dral angle between the diporphyrins may be caused by the phyrin tapes TSn in good yields (62–94%). MALDI-TOF
strong and tight crystal packing in the crystal. In the crys- mass spectroscopy revealed the parent ion peaks for TS2 at
tal, S2 molcules are packed with its porphyrin planes being m/z = 2598.64 (calcd for C168H218N8O8Zn2; m/z = 2608.29),
parallel with those of neighboring S2 molcules with in- TS3 at m/z = 3825.16 (calcd for C246H320N12O12Zn3; m/z =
terplanar distances of ca. 6.6 Å and 7.3 Å (Figure 3, c).
3833.30), and TS4 at m/z = 5048.66 (calcd for
324H422N16O16Zn4; m/z = 5058.32), but the parent ion
The meso–meso-linked porphyrin arrays Sn were con-
C
verted to triply linked porphyrin tapes TSn by the synthetic peaks of higher porphyrin tapes could not be detected by
1
protocol involving meso-bromination, meso-phenyl capping this method. The H NMR spectrum of TS2 in CDCl3 ex-
1
2
reaction, and oxidative ringclosure (Scheme 3).[11d] Treat- hibited a set of mutually coupled doublets for Hβ and Hβ
3
ment of Sn with NBS resulted in nearly quantitative re- at δ = 7.62 ppm and 7.60 ppm, a singlet for Hβ at δ =
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Figure 3. X-ray crystal structure of S2. a) Top view, b) side view, c) crystal packing pattern. Some atoms were omitted for clarity.
Scheme 3. Synthesis of triply linked porphyrins TSn. a) NBS, pyridine, CHCl3, 83–96% b) PhB(OH)2, Pd(PPh3)4, K2CO3, toluene, 79–
94%. c) DDQ, Sc(OTf)3, toluene, 62–95%.
7.24 ppm, and a set of signals due to the strap protons; Ha the porphyrin π planes of higher porphyrin tapes by the
at δ = 3.88 and 3.82 ppm, Hb at δ = 1.14 ppm, Hc at δ = present double alkyl strap.[11e,11f]
0.13 ppm, Hd at δ = 0.05 ppm and He at δ = –0.38 ppm.
The absorption spectra of Sn in CHCl3 are shown in Fig-
These chemical shifts indicated an attenuated diatropic ring ure 4. Similar to the previously reported meso–meso-linked
current of porphyrin rings in TS2 as compared with that in porphyrin oligomers,[16] Sn exhibit split Soret bands and
S2, as the peripheral protons were shifted to high field and red-shifted Q bands. Of the split two Soret bands, the high-
1
the strap protons were shifted to low field. The H NMR energy band remains in the same position as that of S1,
spectrum of TS3 was very broad at room temperature but and the other low-energy band is progressively red-shifted
became sharper at 60 °C, showing broad peaks at δ = as the number of porphyrins increases. These split Soret
1
2
3
7.47 ppm for Hβ and Hβ , δ = 7.04 ppm for Hβ , δ = bands can be understood in terms of the exciton coupling
5
6.34 ppm for Hβ , δ = 3.89, 3.75, and 3.67 ppm for Ha, δ = theory in essentially the same manner as performed for the
0.76 ppm for Hb, –0.14 ppm for Hc and Hd, and δ = non-strapped meso–meso-linked porphyrin oligomers.[16–18]
–0.74 ppm for He. Unfortunately, 1H NMR spectra of As a notable difference from the spectral characteristics of
higher porphyrin tapes (Ͼ TS4) were quite broad and al- the non-strapped arrays and Mn, the lowest energy Q(0,0)
most useless for the structural characterizations. This has bands of Sn are observed as sharp bands, which are pro-
been interpreted in terms of incomplete encapsulation of gressively red-shifted as the number of the porphyrins in-
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Figure 4. Absorption spectra of S1, S2, S3, S4, S6, S8, and S12 in CHCl3.
creases. The Q(0,0) bands of the non-strapped arrays[16a] I are commonly observed around 400 nm at the same posi-
and Mn are broad and almost hidden by Q(0,1) vibronic tion of the Soret band of porphyrin, and bands II are
bands (Supporting Information, see also the footnote on shifted to lower energy with an increase in the number of
the first page of this article).
porphyrins, and bands III are the lowest energy bands and
The fluorescence spectra of Sn and Mn in CHCl3 are more red-shifted with an increase in the number of porphy-
shown in Figure 5. Whereas the fluorescence spectral rins. The bands I and II have been interpreted as split Soret
shapes of Mn are similar to those of the previously reported bands and the bands III have been interpreted as Q-like
non-strapped ones in respect of broad band with three bands on the basis of several theoretical analyses.[17,18] Pro-
bands, Sn exhibit remarkably sharp fluorescence spectra gressive red-shifts of the bands II and III in the present
with intensified 0–0 bands, particularly for longer arrays Ͼ series are similar to those of the non-strapped ones. The
S4. The position of the 0–0 band is gradually red-shifted bands III of TS2 and TS3 show typical vibrational struc-
with an increase in the number of porphyrins, and seems tures of porphyrin consisting of Q(0,0) and Q(0,1) absorp-
saturated at S8 and S12. The red-shifts of the fluorescence tion bands, and interestingly those of TS4 and TS6 partially
Q(0,0) bands correspond to those of the absorption Q- preserve such vibrational structures but that of TS8 is very
bands. The fluorescence quantum yields of Sn determined broad without such structure. In the case of the non-
with respect to ΦF = 0.03 for Zn tetraphenylporphyrin[19] strapped porphyrin tapes, the bands III are broad and
are roughly similar to those of Mn; S1: 0.028, S2: 0.038, structureless for n Ն 4.[11d] These broad bands can be
S3: 0.051, S4: 0.055, S6: 0.066, S8: 0.068, S12: 0.070, M1: mainly ascribed to π–π interaction on the basis of the pre-
0.031, M2: 0.038, M3: 0.049, M4: 0.063, and M6: 0.073. vious studies,[11e,11f] and thus the bands III of TS4 and TS6
The ΦF value increases up to S6 and becomes constant for indicate partial prevention of such π–π interaction by the
S8 and S12, which suggests the coherent length of 6–8 por- double strap but the broad band III in TS8 indicates signifi-
phyrin units for S1 state of Sn, which is similar to that of cant π–π stacking. Figure 7 shows the plots of absorption
the non-strapped arrays.[16a] The enhancement of Q(0,0) ab- peak of Q-like band of TSn vs. the number of porphyrins
sorption bands may be ascribed to the anchoring of meso- n. As noted above, TSn show two absorption bands in the
substituted dialkoxyphenyl groups in Sn, because the rela- band III (TS2–TS6), but longer tape TS8 shows a broad
tively free motions of meso-substituted phenyl groups give band III. Both plots are linear, suggesting that the ECL of
rise to stronger vibronic Q(0,1) bands.[20,21] The restricted TSn is at least larger than 8.
rotational freedom caused by the double strap in Sn series
Since the electronic absorption bands of TSn reach the
can modify the vibronic structure in porphyrin monomers infrared (IR) region, their IR spectra in KBr pellet were
compared to Mn, which leads to the distinct Q(0,0) absorp- examined (Figure 8). In these spectra, bands due to C–H
tion and fluorescence bands.
stretching were observed around 3000 cm–1 and broad
The absorption spectra of TSn (n = 2, 3, 4, 6, and 8) in bands due to O–H stretching of contaminated water were
CHCl3 are shown in Figure 6. A clear absorption spectrum observed around 3600 cm–1. The electronic absorption
of TS12 was not obtained due to its extremely poor solubil- bands III were actually observed at 6600 cm–1 for TS4,
ity in CHCl3 or other solvents. Similarly to the previously 5210 cm–1 for TS6, 4410 cm–1 for TS8, and 3050 cm–1 for
reported non-strapped porphyrin tapes,[11] the absorption TS12. Remarkably, the edge of electronic absorption band
spectra of TSn have main three bands; band I (ca. 400 nm), of TS12 reaches about 1800 cm–1 as a rare example of an
band II (500–1000 nm), and band III (Ͼ 1000 nm). Bands electronic absorption band in the IR region. Furthermore,
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Figure 5. Fluorescence spectra taken for excitation at 411 nm in CHCl3. a) S1, S2, S3, S4, S6, S8, and S12. b) M1, M2, M3, M4, and
M6.
aggregation of TSn in KBr pellet is not extensive in com-
parison to that in CHCl3. Figure 9 shows the plots of the
absorption peak of Q-like band in IR spectra vs. n, which
are both linear, indicating the ECL of TSn larger than 12.
Figure 6. UV/Vis absorption spectra of TS2, TS3, TS4, TS6, and
TS8 in CHCl3.
Figure 8. IR spectra of TS2, TS3, TS4, TS6, TS8, and TS12 in
KBr pellet.
Finally, it is important to note that the chemical stabilit-
ies of TSn are considerably improved compared with the
Figure 7. Plots of absorption peak of Q-like band of TSn in UV/
Vis vs. the number of porphyrins n.
non-strapped porphyrin tapes. The non-strapped porphyrin
tapes octamer and dodecamer were reasonably stable for
their separation and manipulations at ambient temperature
it is noteworthy that the shapes of the bands III in the IR in the air but faded out slowly during storage in a refrigera-
spectra of TSn resemble those of the absorption spectra, tor for one or two months. On the other hand, such changes
and the bands III of TS8 and TS12 possess two bands in were not observed for TS8 and TS12 under the similar con-
contrast to the corresponding electronic absorption band of ditions, demonstrating that the double straps improve the
TS8 that is only broad. These observations suggest that the chemical stabilities of higher porphyrin tapes.
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(98 mL, 407 mmol) dropwise, and the resulting mixture was stirred
until the reaction was finished. A solution of the aldehyde 1 (45.0 g,
271 mmol) in dry diethyl ether (250 mL) was added dropwise to
the mixture at 0 °C, and the resulting mixture was stirred for 3 h,
and then the reaction was quenched by the addition of aqueous
ammonium chloride. The organic layer was separated and the
aqueous layer was further extracted with diethyl ether. The com-
bined organic layer was washed with brine, dried with anhydrous
sodium sulfate, and the solvent was evaporated. Dodecane was re-
moved by vacuum distillation, which induced crystallization of 2
as a colorless solid. Yield 89.9 g (267 mmol, 98%). 1H NMR
(600 MHz, CDCl3): δ = 0.88 (t, J = 7.3 Hz, 3 H, –CH3), 1.22–1.32
[several peaks, 22 H, –(CH2)11–], 1.79 (d, J = 3.2 Hz, 1 H, OH),
3.79 (s, 6 H, OCH3), 4.60 (m, 1 H, Ar-CH), 6.37 (t, J = 2.3 Hz, 1
H, Ar-4-H), and 6.51 ppm (d, J = 2.3 Hz, 2 H, Ar-2,6-H). HRMS
(ESI-TOF): found m/z = 359.2575 ([M+Na]+), calcd. for
C21H36O3Na, m/z = 359.2557.
Figure 9. Plots of absorption peak of Q-like band of TSn in IR vs.
the number of porphyrins n.
In summary, the doubly strapped meso–meso-linked por-
phyrin arrays Sn and triply linked porphyrin tapes TSn were
prepared and characterized. The double straps have been
shown to cause intensified Q(0,0) bands in the absorption
and fluorescene spectra of Sn and to suppress the intermo-
lecular π–π interactions and enhance the chemical stabilities
of TSn.
1,3-Dimethoxy-5-tridecylbenzene (3):
A solution of alcohol 2
(14.7 g, 44 mmol) in dry CH2Cl2 (1 L) was cooled to 0 °C under
nitrogen, to which trifluoroacetic acid (TFA) (49 mL, 656 mmol)
and sodium cyanoborohydride (13.7 g, 219 mmol) were added, and
the resulting mixture was stirred for 3 h. Then the reaction was
quenched by the addition of ice water. The organic layer was sepa-
rated and the aqueous layer was extracted with CH2Cl2. The com-
bined organic layer was washed with aqueous sodium carbonate
and brine, dried with anhydrous sodium sulfate, and the solvents
evaporated. The resulting yellow oil was separated by silica gel
(Wakogel, C-200) column chromatography with hexane as an elu-
Experimental Section
General: All reagents and solvents were of commercial reagent
grade and were used without further purification except where
noted. Dry toluene and dry CH2Cl2 were obtained by distillation
over CaH2. Dry CHCl3 was obtained by distillation over CaH2
1
ent to give 3 as a colorless solid. Yield 8.65 g (27 mmol, 62%). H
NMR (600 MHz, CDCl3): δ = 0.88 (t, J = 6.8 Hz, 3 H, –CH3),
1.22–1.34 [several peaks, 22 H, –(CH2)11–], 2.54 (t, J = 7.7 Hz, 2
H, Ar-CH2), 3.78 (s, 6 H, OCH3), 6.29 (t, J = 1.9 Hz, 1 H, Ar-4-
H), and 6.34 ppm (d, J = 1.9 Hz, 2 H, Ar-2,6-H). HRMS (FAB):
found m/z = 320.343 (M+), calcd. for C21H36O2, m/z = 320.272.
1
and purification through a short basic alumina column. H NMR
spectra were recorded with a Jeol delta-600 spectrometer, and
chemical shifts were reported as the delta scale in ppm relative to
CHCl3 (δ = 7.260 ppm). Spectroscopic-grade CHCl3 was used as
solvent for spectroscopic studies. UV/Visible/NIR absorption spec-
tra were recorded with a Shimadzu UV-3100 spectrometer. Fluores-
cence spectra were recorded with Shimadzu RF-5300PC spectrom-
eter. IR spectra were recorded with Jasco FT/IR-420 spectrometer.
Mass spectra were recorded with a Shimadzu Kratos Kompact
Maldi4 using positive-Maldi ionization method with/without 9-ni-
troanthracene (9NA) matrix, with a Jeol HX-110 spectrometer with
the positive-FAB ionization method (accelerating voltage, 10 kV;
primary ion sources, Xe) and 3-nitrobenzyl alcohol matrix, and
with a Bruker microTOF using positive or negative mode ESI-TOF
method of acetonitrile solution. Preparative separations were per-
formed by silica gel flash column chromatography (Merck, Kiesel-
gel 60H, Art. no. 7736), silica gel gravity column chromatography
(Wakogel C-400), and size exclusion gel permeation chromatog-
raphy (Bio-Rad Bio-Beads S-X1, packed with toluene or CHCl3 in
a 4×100 cm gravity flow column: flow rate, 3.8 mL·min–1). Analyt-
ical GPC-HPLC was performed with Jaigel 2.5H-AF, 3H-AF, and
4H-AF columns in series with a Jasco HPLC system using a multi-
wavelength detector MD-915. Recycling preparative GPC-HPLC
separations were carried out with JAI LC-908 using preparative
Jaigel-2.5 H, 3 H, and 4H columns in series. Redox potentials were
measured by the cyclic voltammetry method and differential pulse
voltammetry method with an ALS electrochemical analyzer model
660. X-ray crystallography was performed on a Rigaku-Raxis im-
aging plate system (Raxis Rapid).
2,6-Dimethoxy-4-tridecylbenzaldehyde (4): 3,5-Dimethoxy-1-tride-
cylbenzene (3, 56.1 g, 178 mmol) and N,N,NЈ,NЈ-tetramethylethyl-
enediamine (TMEDA) (160 mL) were dissolved in dry diethyl ether
(500 mL). This solution was cooled to –78 °C under nitrogen, and
a white solid precipitated. Butyllithium (155 mL of 1.58  solution
in hexane, 246 mmol) was added dropwise to the solution, and the
resulting mixture was stirred for 4 h. The color of the mixture grad-
ually changed to orange, and then red. The reaction temperature
was warmed to room temperature, and the mixture was stirred for
an additional 3 h. The color of the mixture immediately changed
to black. Then, dimethylformamide (DMF) (16.0 mL, 206 mmol)
was added dropwise to the mixture and the resulting mixture was
stirred for 2 h, which induced a color change to brown. The mixture
was poured into ice water and the organic layer was separated.
The aqueous layer was further extracted with diethyl ether, and the
combined organic layer was washed with 3  hydrochloric acid,
saturated aqueous sodium hydrogen carbonate and brine, dried
with anhydrous sodium sulfate, and the solvents evaporated. A so-
lid precipitated during evaporation. The product 4 was obtained by
recrystallization from ethyl acetate as the first crop. Further the
filtrate was purified by silica gel (Wakogel C-300) column
chromatography (AcOEt/hexane, 1:1) to give 4 as the second crop
as a colorless solid. Yield 36.6 g (112 mmol, 56%). 1H NMR
(600 MHz, CDCl3): δ = 0.88 (t, J = 6.8 Hz, 3 H, –CH3), 1.22–1.34
[several peaks, 20 H, –(CH2)10–], 1.63 (m, 2 H, Ar-CH2CH2), 2.60
(t, J = 7.8 Hz, 2 H, Ar-CH2), 3.89 (s, 6 H, OCH3), 6.38 (s, 2 H, Ar-
H), and 10.45 (s, 1 H, CHO). HRMS (FAB): found m/z = 349.331
([M+H]+), calcd. for C22H36O3, m/z = 349.274.
5-(1-Hydroxytridecyl)-1,3-dimethoxybenzene (2): To a suspension of
magnesium turnings (19.8 g, 814 mmol) and a piece of iodine in dry
diethyl ether (300 mL) under nitrogen was added dodecyl bromide
3200
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© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2006, 3193–3204

Doubly Strapped meso–meso-Linked Porphyrin Arrays and Triply Linked Tapes
FULL PAPER
Methoxyphenyl-Substituded Porphyrin 6: The porphyrin 6 was pre-
pared from the aldehyde 4 (7.18 g, 20.6 mmol) and dipyrromethane
(5) (3.00 g, 20.6 mmol) according to the published method.[22] Pur-
ple solid. Yield 2.91 g (3.07 mmol, 30%). 1H NMR (600 MHz,
saturated solution of Zn(OAc)2 in methanol, and the resulting mix-
ture was stirred for 3 h. Then, water was added to the solution and
the products were extracted with CHCl3. The organic layer was
washed with brine, dried with anhydrous sodium sulfate, and the
CDCl3): δ = –3.03 (s, 2 H, NH), 0.90 (t, J = 6.6 Hz, 6 H, -CH3), solvents evaporated. The product was purified by silica-gel column
1.27–1.42 [several peaks, 28 H, –(CH2)7–], 1.45 (m, 4 H, –CH2–), chromatography with CH2Cl2/hexane and subsequent recrystalli-
1.52 (m, 4 H, –CH2–), 1.59 (m, 4 H, –CH2–), 1.96 (m, 4 H, zation from CHCl3/acetonitrile, giving porphyrin M1 (101 mg,
1
–CH2–), 2.95 (t, J = 7.8 Hz, 4 H, Ar-CH2), 3.51 (s, 12 H, Ar–
98%). H NMR (600 MHz, CDCl3): δ = 0.90 (t, J = 6.9 Hz, 6 H,
OCH3), 6.87 (s, 4 H, Ar-H), 8.97 (d, J = 4.8 Hz, 4 H, β), 9.28 (d, –CH3), 1.25–1.40 [several peaks, 32 H, –(CH2)8–], 1.46 (m, 4 H,
J = 4.8 Hz, 4 H, β), and 10.14 ppm (s, 2 H, meso). HRMS (ESI-
TOF): found m/z = 947.6405 ([M+H]+), calcd. for C62H83N4O4,
m/z = 947.6409. UV/Vis (CHCl3): λmax = 409, 503, 536, and
576 nm.
–CH2–), 1.63 (m, 4 H, –CH2–), 1.97 (m, 4 H, –CH2–), 2.97 (t, J =
7.3 Hz, 4 H, Ar-CH2), 3.52 (s, 12 H, OMe), 6.88 (s, 4 H, Ar-H),
9.06 (d, J = 4.8 Hz, 4 H, β), 9.35 (d, J = 4.8 Hz, 4 H, β), and
10.19 ppm (s, 2 H, meso). HRMS (MALDI-TOF): found m/z =
1010.41, calcd. for C62H80N4O4Zn, m/z = 1010.69. UV/Vis
(CHCl3): λmax (ε) = 414 (404000) and 541 (17000)nm; fluorescence
(CHCl3): λmax = 584 and 635 nm.
General Procedure for AgI-Promoted meso–meso Coupling Reaction:
To a solution of meso-free ZnII-porphyrin in dry CHCl3 (1.0 m)
was added a stock solution of AgPF6 in acetonitrile (0.12 ) under
N2 in the dark. The reaction mixture was stirred for appropriate
time and the reaction was quenched by the addition of water. The
organic layer was separated, washed with brine, dried with Na2SO4,
and the solvents evaporated. The residue was passed through a
short silica gel column and separated by GPC chromatography.
Further purification by silica gel column chromatography (Wakogel
C-400) and recrystallization from CHCl3/acetonitrile provided
meso–meso-linked oligomers.
Hydroxyphenyl-Substituded ZnII-Porphyrin 7: The porphyrin 6
(2.37 g, 2.50 mmol) was dissolved in dry CH2Cl2 (140 mL) and co-
oled to –78 °C under N2, to which a solution of BBr3 (25 g,
100 mmol) in dry CH2Cl2 (70 mL) was added slowly at –78 °C. The
reaction mixture was stirred for 20 h at room temperature, poured
into water, and neutralized with aqueous NaHCO3. The organic
layer was separated, washed with water and brine, and the solvents
evaporated. The resulting purple solid was dissolved in methanol
(1 L), and concd. hydrochloric acid (23 mL) was added. The re-
sulting solution was stirred for 15 h under reflux, and then
quenched with triethylamine (40 mL) and evaporated until the vol-
ume of the solution became ca. 500 mL. Then water was added to
precipitate a purple solid. After filtration, the solid was dissolved
in methanol (500 mL), stirred with Zn(OAc)2 for 20 h at room tem-
perature and evaporated until the volume of the solution became
ca. 300 mL. Then, water was added to precipitate a purple solid,
which was filtered and recrystallized (ethyl acetate/hexane) to give
7 (2.35 g, 98%). 1H NMR (600 MHz, CDCl3): δ = 0.90 (t, J =
6.8 Hz, 6 H, –CH3), 1.26–1.41 [several peaks, 28 H, –(CH2)7–], 1.44
(m, 4 H, –CH2–), 1.51 (m, 4 H, –CH2–), 1.59 (m, 4 H, –CH2–),
1.93 (m, 4 H, –CH2–), 2.89 (t, J = 7.4 Hz, 4 H, Ar-CH2), 4.67 (s,
4 H, Ar–OH), 6.87 (s, 4 H, Ar-H), 9.25 (d, J = 4.1 Hz, 4 H, β),
9.50 (d, J = 4.1 Hz, 4 H, β), and 10.36 ppm (s, 2 H, meso). HRMS
(ESI-TOF): found m/z = 953.4813 ([M+H]+), calcd. for
C58H73N4O4Zn, m/z = 953.4918. UV/Vis (CHCl3): λmax = 413, 542,
and 573 nm.
AgI-Promoted meso–meso Coupling Reaction of S1: Following the
general procedure (4 equiv. of AgPF6, 48 h, under reflux), S1 was
coupled to provide S2 (21%), S3 (3%), and S4 (trace) along with
1
recovery of S1 (52%). S2: H NMR (600 MHz, CDCl3): δ = –2.18
(m, 16 H, He), –1.25 (m, 16 H, Hd), –0.99 (m, 16 H, Hc), 0.77 (m,
16 H, Hb), 0.85 (t, J = 6.9 Hz, 12 H, –CH3), 1.20–1.37 [several
peaks, 56 H, –(CH2)7–], 1.40 (m, 8 H, –CH2–), 1.48 (m, 8 H,
–CH2–), 1.58 (m, 8 H, –CH2–), 1.82 (m, 8 H, –CH2–), 2.82 (t, J =
7.7 Hz, 8 H, Ar-CH2), 3.75 (m, 16 H, Ha), 6.89 (s, 8 H, Ar-H), 8.04
(d, J = 4.6 Hz, 4 H, β), 8.64 (d, J = 4.6 Hz, 4 H, β), 9.10 (d, J =
4.6 Hz, 4 H, β), 9.41 (d, J = 4.6 Hz, 4 H, β), and 10.25 ppm (s, 2
H, meso). HRMS (MALDI-TOF): found m/z = 2455.52, calcd. for
Doubly Strapped ZnII-Porphyrin S1: The porphyrin 7 (621 mg,
651 µmol), 1,10-dibromodecane (1.95 g, 6.51 mmol), and K2CO3
(5.40 g, 39.1 mmol) were dissolved in acetone (950 mL) under N2,
and the mixture was stirred for 20 days under reflux. The reaction
mixture was filtered and the filtrate was evaporated. The resulting
solid was dissolved in CHCl3 (300 mL) and water (200 mL). The
organic layer was separated, washed with brine, and dried with
Na2SO4 and the solvents evaporated. Acetonitrile was added to the
resulting solution and the mixture was filtered. The residue was
purified by silica gel (Wakogel C-400) column chromatography
(CH2Cl2/hexane, 7:3) and recrystallized from CHCl3/acetonitrile to
give the porphyrin S1 (496 mg, 62%). 1H NMR (600 MHz,
CDCl3): δ = –2.48 (m, 8 H, He), –1.44 (m, 8 H, Hd), –1.34 (m, 8
H, Hc), 0.65 (m, 8 H, Hb), 0.90 (t, J = 6.9 Hz, 6 H, –CH3), 1.25–
1.40 [several peaks, 28 H, –(CH2)7–], 1.43 (m, 4 H, –CH2–), 1.50
(m, 4 H, –CH2–), 1.59 (m, 4 H, –CH2–), 1.93 (m, 4 H, –CH2–),
2.93 (t, J = 7.3 Hz, 4 H, Ar-CH2), 3.76 (t, J = 5.0 Hz, 8 H, Ha),
6.98 (s, 4 H, Ar-H), 9.11 (d, J = 4.1 Hz, 4 H, β), 9.37 (d, J = 4.1 Hz,
4 H, β), and 10.22 ppm (s, 2 H, meso). HRMS (ESI-TOF): found
m/z = 1229.7733 ([M+H]+), calcd. for C78H108N4O4Zn, m/z =
1229.7735. UV/Vis (CHCl3): λmax (ε) = 409 (404000) and 536
(21000) nm; fluorescence (CHCl3): λmax = 575 and 631 nm.
C
156H214N8O8Zn2, m/z = 2452.75. UV/Vis (CHCl3): λmax (ε) = 413
(231000), 446 (198000), 551 (59000), and 591 (18000) nm; fluores-
cence (CHCl3): λmax = 593 and 650 nm. S3: H NMR (600 MHz,
1
CDCl3): δ –2.15 (m, 16 H, He), –1.84 (m, 8 H, He), –1.22 (m, 16
H, Hd), –1.01 (m, 16 H, Hc), –0.96 (m, 8 H, Hd), –0.71 (m, 8 H,
Hc), 0.76–0.91 (m, 24 H, Hb), 0.79 (t, J = 6.8 Hz, 6 H, –CH3), 0.87
(t, J = 10.1 Hz, 12 H, –CH3), 1.12–1.39 [several peaks, 92 H,
–(CH2)n–], 1.43 (m, 8 H, –CH2–), 1.51 (m, 8 H, –CH2–), 1.70 (m,
4 H, –CH2–), 1.86 (m, 8 H, –CH2–), 2.71 (t, J = 6.8 Hz, 4 H, Ar-
CH2), 2.86 (t, J = 6.9 Hz, 8 H, Ar-CH2), 3.75 (t, J = 5.1 Hz, 8 H,
Ha), 3.79 (t, J = 5.0 Hz, 16 H, Ha), 6.81 (s, 4 H, Ar-H), 6.93 (s, 8
H, Ar-H), 8.08 (d, J = 4.6 Hz, 4 H, β), 8.19 (d, J = 4.6 Hz, 4 H,
β), 8.63 (d, J = 4.6 Hz, 4 H, β), 8.73 (d, J = 4.6 Hz, 4 H, β), 9.14
(d, J = 4.1 Hz, 4 H, β), 9.43 (d, J = 4.1 Hz, 4 H, β), and 10.28 ppm
(s, 2 H, meso). HRMS (MALDI-TOF): found m/z = 3685.28, calcd.
for C234H320N12O12Zn3, m/z = 3682.27. UV/Vis (CHCl3): λmax (ε)
= 410 (358000), 471 (278000), 561 (110000), and 601 (40000) nm;
fluorescence (CHCl3): λmax = 603 and 659 nm. S4: 1H NMR
(600 MHz, CDCl3): δ = –2.13 (m, 16 H, He), –1.81 (m, 16 H, He),
–1.20 (m, 16 H, Hd), –1.00 (m, 16 H, Hc), –0.96 (m, 16 H, Hd),
–0.66 (m, 16 H, Hc), 0.81 (t, J = 6.8 Hz, 12 H, –CH3), 0.82 (m, 16
H, Hb), 0.87 (t, J = 6.9 Hz, 12 H, –CH3), 0.92 (m, 16 H, Hb), 1.13–
1.34 [several peaks, 136 H, –(CH2)n–], 1.37 (m, 8 H, –CH2–), 1.43
(m, 8 H, –CH2–), 1.52 (m, 8 H, –CH2–), 1.74 (m, 8 H, –CH2–),
5,15-Bis(2,6-dimethoxyphenyl)-Substituted ZnII-Porphyrin M1: To a
solution of 6 (100 mg, 105 µmol) in CHCl3 (10 mL) was added a
Eur. J. Org. Chem. 2006, 3193–3204
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
3201

T. Ikeda, J. M. Lintuluoto, N. Aratani, Z. S. Yoon, D. Kim, A. Osuka
FULL PAPER
1.87 (m, 8 H, –CH2–), 2.74 (t, J = 7.8 Hz, 8 H, Ar-CH2), 2.86 (t,
8.74–8.79 (ten peaks of d, 40 H, β), 9.15 (d, J = 4.1 Hz, 4 H, β),
J = 7.4 Hz, 8 H, Ar-CH2), 3.80 (t, J = 5.1 Hz, 16 H, Ha), 3.81 (t, 9.45 (d, J = 4.1 Hz, 4 H, β), and 10.29 ppm (s, 2 H, meso).
J = 5.0 Hz, 16 H, Ha), 6.85 (s, 8 H, Ar-H), 6.94 (s, 8 H, Ar-H),
8.10 (d, J = 4.6 Hz, 4 H, β), 8.21 (d, J = 4.6 Hz, 4 H, β), 8.22 (d,
J = 4.6 Hz, 4 H, β), 8.67 (d, J = 4.6 Hz, 4 H, β), 8.72 (d, J =
4.6 Hz, 4 H, β), 8.74 (d, J = 4.6 Hz, 4 H, β), 9.15 (d, J = 4.1 Hz,
4 H, β), 9.44 (d, J = 4.1 Hz, 4 H, β), and 10.29 ppm (s, 2 H, meso).
HRMS (MALDI-TOF): found m/z = 4908.75, calcd. for
C312H426N16O16Zn4, m/z = 4909.02. UV/Vis (CHCl3): λmax (ε) =
411 (408000), 484 (348000), 568 (148000), and 606 (32000) nm;
fluorescence (CHCl3): λmax = 608 and 662 nm.
HRMS (MALDI-TOF): found m/z = 14742.72, calcd. for
936H1274N48O48Zn12, m/z = 14750.71. UV/Vis (CHCl3): λmax (ε) =
411 (587000), 502 (586000), 576 (379000), and 614 (174000) nm;
C
fluorescence (CHCl3): λmax = 613 and 663 nm.
General Procedure for Bromination of Sn: To a solution of Sn
(10 mg) in CHCl3 (10 mL) was added 2.2 equiv. of NBS. After the
reaction mixture was stirred at 0 °C for 1 h, the reaction was
quenched by addition of water. The organic layer was separated,
washed with brine, dried with Na2SO4, and the solvent was evapo-
rated. The resulting residue was passed through a short silica gel
column. Recrystallization from a mixture of CHCl3 and acetoni-
trile gave BSn.
AgI-Promoted meso–meso Coupling Reaction of S2: Following the
general procedure (4 equiv. of AgPF6, 48 h, under reflux), S2 was
coupled to provide S4 (21%), S6 (4%), and S8 (trace) along with
1
recovery of S2 (57%). S6: H NMR (600 MHz, CDCl3): δ = –2.12
(m, 16 H, He), –1.77 (m, 16 H, He), –1.75 (m, 16 H, He), –1.19 (m,
16 H, Hd), –0.97 (m, 32 H, Hd), –0.97 (m, 16 H, Hc), –0.62 (m, 32
H, Hc), 0.81 (t, J = 7.8 Hz, 12 H, –CH3), 0.82 (m, 16 H, Hb), 0.83
(t, J = 6.8 Hz, 12 H, –CH3), 0.88 (t, J = 6.4 Hz, 12 H, –CH3), 0.95
(m, 32 H, Hb), 1.14–1.47 [several peaks, 232 H, –(CH2)n–], 1.53 (m,
8 H, –CH2–), 1.77 (m, 16 H, –CH2–), 1.88 (m, 8 H, –CH2–), 2.75
(t, J = 7.3 Hz, 8 H, Ar-CH2), 2.78 (t, J = 6.8 Hz, 8 H, Ar-CH2),
2.87 (t, J = 7.4 Hz, 8 H, Ar-CH2), 3.80–3.84 (three peaks of t, 48
H, Ha), 6.86 (s, 8 H, Ar-H), 6.90 (s, 8 H, Ar-H), 6.95 (s, 8 H, Ar-
H), 8.11 (d, J = 4.6 Hz, 4 H, β), 8.23 (d, J = 4.6 Hz, 4 H, β), 8.24–
8.28 (three peaks of d, 12 H, β), 8.67 (d, J = 4.6 Hz, 4 H, β), 8.73–
8.78 (four peaks of d, 16 H, β), 9.15 (d, J = 4.1 Hz, 4 H, β), 9.44
General Procedure for Phenyl Capping Reaction of BSn: To a solu-
tion of BSn (10 mg) in dry toluene (10 mL) was added PhB(OH)2
(10 equiv.), Pd(PPh3)4 (0.1 equiv.), and K2CO3 (20 equiv.) and the
resulting mixture was degassed by three times of freeze-pump-de-
gassing cycles and stirred for 8 h under reflux under N2. After the
reaction was quenched by the addition of water, the organic layer
was separated, washed with brine, dried with Na2SO4, and the sol-
vent was evaporated. After the resulting residue was passed through
a short silica gel column, recrystallization from a mixture of CHCl3
and acetonitrile provided PSn.
General Procedure for DDQ-Sc(OTf)3 Oxidation: To a solution of
PSn (10 mg) in dry toluene (10 mL) was added 4 equiv. of DDQ
and 4 equiv. of Sc(OTf)3. The resulting reaction mixture was stirred
at 80 °C for 2 h under N2 in the dark and the reaction was
quenched by the addition of THF. The resulting mixture was
passed through a short alumina column and the solvent was evapo-
rated. Recrystallization from a mixture of CHCl3 and acetonitrile
provided TSn.
(d,
HRMS (MALDI-TOF): found m/z = 7363.33, calcd. for
468H638N24O24Zn6, m/z = 7362.52. UV/Vis (CHCl3): λmax (ε) =
J = 4.1 Hz, 4 H, β), and 10.29 ppm (s, 2 H, meso).
C
411 (557000), 494 (514000), 572 (268000), and 611 (93000) nm;
fluorescence (CHCl3): λmax = 611 and 662 nm. S8: 1H NMR
(600 MHz, CDCl3): δ = –2.11 (m, 16 H, He), –1.77 (m, 16 H, He),
–1.74 (m, 32 H, He), –1.19 (m, 16 H, Hd), –0.94 (m, 64 H, Hd and
Hc), –0.60 (m, 48 H, Hc), 0.80–0.89 (several peaks, 64 H, Hb and
-CH3), 0.94 (m, 16 H, Hb), 0.99 (m, 32 H, Hb), 1.14–1.38 [several
peaks, 288 H, –(CH2)n–], 1.43 (m, 24 H, –CH2–), 1.60 (m, 8 H,
–CH2–), 1.77 (m, 24 H, –CH2–), 1.88 (m, 8 H, –CH2–), 2.74–2.80
(three peaks of t, 24 H, Ar-CH2), 2.87 (t, J = 6.4 Hz, 8 H, Ar-
CH2), 3.78–3.87 (four peaks of t, 64 H, Ha), 6.86 (s, 8 H, Ar-H),
6.90 (s, 8 H, Ar-H), 6.91 (s, 8 H, Ar-H), 6.95 (s, 8 H, Ar-H), 8.12
(d, J = 4.6 Hz, 4 H, β), 8.23 (d, J = 4.6 Hz, 4 H, β), 8.24–8.29 (five
peaks of d, 20 H, β), 8.68 (d, J = 4.6 Hz, 4 H, β), 8.74–8.79 (six
peaks of d, 24 H, β), 9.15 (d, J = 4.1 Hz, 4 H, β), 9.45 (d, J =
4.1 Hz, 4 H, β), and 10.29 ppm (s, 2 H, meso). HRMS (MALDI-
TOF): found m/z = 9824.21, calcd. for C624H850N32O32Zn8, m/z =
9826.10. UV/Vis (CHCl3): λmax (ε) = 411 (529000), 498 (520000),
Following the general procedure, TS2 was prepared from PS2 in
92% yield as red-purple solid. 1H NMR (600 MHz, CDCl3): δ =
–0.38 (m, 16 H, He), 0.07 (m, 16 H, Hd), 0.11 (m, 16 H, Hc), 0.89
(t, J = 6.9 Hz, 12 H, –CH3), 1.15 (m, 16 H, Hb), 1.24–1.38 [several
peaks, 64 H, –(CH2)8–], 1.43 (m, 8 H, –CH2–), 1.49 (m, 8 H,
–CH2–), 1.81 (m, 8 H, –CH2–), 2.78 (t, J = 7.3 Hz, 8 H, Ar-CH2),
3.82 (m, 8 H, Ha), 3.88 (m, 8 H, Ha), 6.74 (s, 8 H, Ar-H), 7.23 (s,
4 H, β), 7.54 (m, 2 H, Ph-p-H), 7.55 (m, 4 H, Ph-m-H), 7.60 (d, J
= 4.6 Hz, 4 H, β), 7.62 (d, J = 4.6 Hz, 4 H, β), and 7.79 ppm (m,
4 H, Ph-o-H). HRMS (MALDI-TOF): found m/z = 2598.64, calcd.
for C168H218N4O4Zn2, m/z = 2608.29. UV/Vis (CHCl3): λmax (ε) =
416 (112000), 554 (74000), 586 (87000), 895 (13000), and 1024
(23000) nm.
574 (304000), and 612 (114000) nm; fluorescence (CHCl3): λmax
612 and 663 nm.
=
Following the general procedure, TS3 was prepared from PS3 in
87% yield as a green solid. H NMR (600 MHz, CDCl3, 60 °C): δ
1
AgI-Promoted meso–meso Coupling Reaction of S4: Following the
general procedure (9 equiv. of AgPF6, 48 h, at 40 °C), S4 was cou-
pled to provide S8 (10%), S12 (5%), and S16 (trace) along with
= –0.74 (m, 24 H, He), –0.14 (m, 48 H, Hc and Hd), 0.76 (m, 24
H, Hb), 0.93 (m, 18 H, –CH3), 1.24–1.55 [several peaks, 120 H,
–(CH2)10–], 1.82 (m, 8 H, –CH2–), 2.78 (m, 8 H, Ar-CH2), 3.67 (m,
8 H, Ha), 3.75 (m, 8 H, Ha), 3.89 (m, 8 H, Ha), 6.34 (br., 4 H, β),
6.62 (s, 4 H, Ar-H), 6.66 (s, 8 H, Ar-H), 7.04 (br., 4 H, β), 7.47
(several peaks, 14 H, β, Ph-m-H and Ph-p-H), and 7.79 ppm (m, 4
H, Ph-o-H). HRMS (MALDI-TOF): found m/z 3825.16, calcd. for
C246H320N12O12Zn3, m/z 3833.30. UV/Vis (CHCl3): λmax = 418,
676, 1114, and 1294 nm.
1
recovery of S4 (33%). S12: H NMR (600 MHz, CDCl3): δ –2.11
(m, 16 H, He), –1.77 (m, 16 H, He), –1.72 (m, 64 H, He), –1.19 (m,
16 H, Hd), –0.94 (m, 96 H, Hd and Hc), –0.57 (m, 80 H, Hc), 0.80–
0.89 (several peaks, 88 H, Hb and –CH3), 0.94 (m, 16 H, Hb), 0.99
(m, 64 H, Hb), 1.14–1.38 [several peaks, 432 H, –(CH2)n–], 1.43 (m,
40 H, –CH2–), 1.60 (m, 8 H, –CH2–), 1.77 (m, 40 H, –CH2–), 1.88
(m, 8 H, –CH2–), 2.74–2.80 (several peaks, 40 H, Ar-CH2), 2.87
(m, 8 H, Ar-CH2), 3.78–3.87 (six peaks of t, 96 H, Ha), 6.86 (s, 8
Following the general procedure, TS4 was prepared from PS4 in
H, Ar-H), 6.90 (s, 8 H, Ar-H), 6.92 (s, 24 H, Ar-H), 6.95 (s, 8 H, 74% yield as a green solid. HRMS (MALDI-TOF): found
Ar-H), 8.12 (d, J = 4.6 Hz, 4 H, β), 8.23 (d, J = 4.6 Hz, 4 H, β),
8.24–8.29 (nine peaks of d, 36 H, β), 8.68 (d, J = 4.6 Hz, 4 H, β),
m/z 5048.66, calcd. for C324H422N16O16Zn4, m/z 5058.32. UV/Vis
(CHCl3): λmax = 504, 716, 1282, and 1466 nm.
3202
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Eur. J. Org. Chem. 2006, 3193–3204

Doubly Strapped meso–meso-Linked Porphyrin Arrays and Triply Linked Tapes
FULL PAPER
Müllen, Chem. Rev. 2001, 101, 1267; j) F. Diederich, Chem.
Commun. 2001, 219.
Following the general procedure, TS6 was prepared from PS6 in
95% yield as green solid. UV/Vis (CHCl3): λmax = 400, 770, 1556,
and 1772 nm.
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Following the general procedure, TS8 was prepared from PS8 in
78% yield as a green solid. UV/Vis (CHCl3): λmax = 406, 830, and
1982 nm.
Following the general procedure, TS12 was prepared from PS12 in
62% yield as a green solid.
Crystallographic Data Collection and Structure Refinement: Data
collection for the S1 was carried out at –150 °C with a Rigaku
Raxis-Rapid with graphite-monochromated Mo-Ka radiation (λ =
0.71069 Å). Data collection for the compounds S2 was carried out
at –183 °C on a Bruker SMART APEX with graphite-monochro-
mated Mo-Ka radiation (λ = 0.71069 Å). Details of the X-ray mea-
surements are given in Table 1. The structures were solved by direct
methods (Sir 97[23] or SHELXS-97[24]) and refined with Rigaku
CrystalStructure software or with full-matrix least square pro-
cedures on F2 for all reflections (SHELXL-97).[24]
[3]
[4]
Table 1. Crystal data and structure refinements of S1 and S2.
S1
S2
J.-H. Chou, M. E. Kosal, H. S. Nalwa, N. A. Rakow, K. S. Sus-
lick, The Porphyrin Handbook (Eds.: K. M. Kadish, K. M.
Smith, R. Guilard), Academic Press, San Diego, 2000, Vol. 6,
Chapter 41.
Formula
Mr
T [K]
C78H108N4O4Zn
1231.05
123
C156H214N8O8Zn2
2460.22
90(2)
[5]
[6]
Crystal system
Space group
a [Å]
b [Å]
c [Å]
α [°]
β [°]
monoclinic
P21/c
14.1291(5)
10.2235(3)
23.1373(7)
90
90.1800(11)
90
3342.14(18)
2
1.223
4.21
1332
0.70×0.40×0.10
55.0
monoclinic
P21/n
13.0780(17)
33.438(5)
31.055(4)
90
92.556(8)
90
13567(3)
4
1.204
4.15
5320
0.70×0.30×0.10
55.0
19542
52792
1580
0.0750
0.1866
0.979
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γ [°]
V [Å3]
Z
ρcalcd. [g cm–3]
µ [cm–1]
F (000)
Crystal size [mm]
2θmax [°]
[7]
[8]
Observed reflections 7533
Total reflections
Parameters
R1 [I Ͼ 2σ(I)]
wR2 [I Ͼ 2σ(I)]
GOF
24488
395
0.0755
0.1945
1.359
CCDC-299457 (for S1), and -299458 (for S2) contain the supple-
mentary crystallographic data for this paper. These data can be
obtained free of charge from The Cambridge Crystallographic
Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
Supporting Information (see footnote on the first page of this arti-
cle): Experimental procedure and spectroscopic data for Mn, BSn,
and PSn, and UV/Vis absorption spectra of Sn and Mn.
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www.eurjoc.org
3203

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