Synthesis and photophysical properties of porphyrins with fluorenyl pendant arms

Article abstract of DOI:10.1016/j.tet.2009.02.015

Symmetrical-A₄-porphyrins bearing four fluorene donor moieties TOFP (5,10,15,20-tetra(4-(2 methyloxyfluorenyl)phenyl)porphyrin) as well as eight fluorene arms OOFP (5,10,15,20-octa(3,5-(2-methyloxyfluorenyl)phenyl)porphyrin) were synthesized an

Full text of DOI:10.1016/j.tet.2009.02.015

Tetrahedron 65 (2009) 2975–2981
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Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Synthesis and photophysical properties of porphyrins with fluorenyl
pendant arms
,
b
,
a
Samuel Drouet a, Christine O. Paul-Roth a , Gerard Simonneaux
*
´
a Unite´ Sciences Chimiques de Rennes, UMR 6226 CNRS - Universite´ de Rennes 1, Equipe Inge´nierie Chimique et Mole´cules pour le Vivant (ICMV), 35042 Rennes Cedex, France
b Institut National des Sciences Applique´es - INSA de Rennes, 20 Avenue des Buttes de Coe¨smes, 35043 Rennes, France
a r t i c l e i n f o
a b s t r a c t
Article history:
Symmetrical-A4-porphyrins bearing four fluorene donor moieties TOFP (5,10,15,20-tetra(4-(2 methyl-
oxyfluorenyl)phenyl)porphyrin) as well as eight fluorene arms OOFP (5,10,15,20-octa(3,5-(2-methyloxy-
fluorenyl)phenyl)porphyrin) were synthesized and characterized. Preliminary photophysical properties
are reported. In comparison to the reference tetraphenylporphyrin TPP, the luminescence properties are
slightly improved. The fluorescence quantum yields of tetrafluorenylporphyrin TOFP (1) and octa-
fluorenylporphyrin OOFP (2) are 0.10 and 0.13, respectively.
Received 4 July 2008
Received in revised form
3 February 2009
Accepted 4 February 2009
Available online 11 February 2009
Ó 2009 Elsevier Ltd. All rights reserved.
Keywords:
Fluorescence
Porphyrins
Fluorene
Light harvesting
Quantum yield
1. Introduction
via spacers, to four donor hydrocarbons, forms a suitable choice for
9
´
the antenna function. On the other hand, Frechet demonstrated
Porphyrin systems, as energy acceptors, have been covalently
linked to donor units like carotenoids1,2 or anthracenes3 to model
photosynthetic systems and to develop efficient molecular devices.
The porphyrin skeleton permits to attach easily four energy donor
arms in the near periphery, and such a light-harvesting system can
be expected to show an antenna effect. Antenna systems com-
prising a central porphyrin linked to four peripheral photon-har-
vesting hydrocarbon moieties have been reported. For example,
naphthalene,4 anthracene5 or phenanthrene6 groups have been
linked directly to four meso-carbons of the porphyrin and more
recently a series of star-shaped porphyrins bearing pendant linear
oligofluorene arms have also been reported.7,8 In the previous do-
nor–acceptor (D–A) system described, the energy donors are linked
directly to the porphyrin periphery. For antenna effect, it is better to
have a multicomponent structure in which the donors and accep-
tors retain their individual characteristics. For a realistic description
of the photosynthetic antenna function, a porphyrin-based model
system should exhibit high local concentrations of the light-har-
vesting chromophores. All of these considerations indicate that
a molecular pentad system, in which a porphyrin acceptor is linked,
that antenna effect was facilitated in dendritic case versus the
corresponding linear case. Thus, more recently, light-harvesting
donor two-photon absorbing chromophores (TPAC) with metalated
porphyrin cores were synthesized in this group.10 The same year,
the synthesis of hyperbranched polymers containing porphyrin
core possessing fluorene arms has been reported, for tuning the
optical properties of hyperbranched polymers through the modi-
fication of the end groups.11
In our previous papers, we have reported the synthesis of a free
macrocycle possessing four pendant fluorene arms directly con-
nected at the meso positions (TFP) and evidenced that the ruth-
enium(II) complexes of this type are very efficient heterogeneous
catalysts.12–15 Recently, we focused on the photophysical properties
of such porphyrins possessing four identical fluorene pendant
arms.16,17 These porphyrins exhibited high quantum yields (22%), so
a complete family of relevant porphyrins was studied to investigate
this high luminescence efficiency. It was demonstrated therein the
good capacity of the fluorenyl units to enhance quantum yields by
increasing the radiative process.18
The present report deals with the design of a new building
block based on fluorenyl porphyrins with the aim to exploit this
capacity to enhance quantum yields and to combine this advan-
´
tage with Frechet’s style dendritic architecture in order to im-
* Corresponding author. Tel.: þ33 02 23 23 63 72; fax: þ33 02 23 23 56 37.
E-mail address: christine.paul@univ-rennes1.fr (C.O. Paul-Roth).
prove energy transfer. The target is to obtain highly luminescent
0040-4020/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2009.02.015

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S. Drouet et al. / Tetrahedron 65 (2009) 2975–2981
organic compounds, by the design of porphyrins possessing flu-
orenyl arms using dendritic synthesis. In more detail, in this
paper, we present the synthesis of systems in which a 5,10,15,20-
tetraphenylporphyrin (TPP) is linked, via ether bridges, to four
and eight fluorene donor moieties, compounds 1 and 2, re-
spectively (Fig. 1), and in a second part preliminary photophysical
results are also reported.
2. Results and discussion
2.1. Synthesis
2-Hydroxyl-methyl-fluorene (7) was obtained by reduction of
fluorene-2-carboxaldehyde with sodium borohydride in ethanol.
After 1 h reaction time followed by extraction with dichloromethane,
CH2
O
CH2
O
N
H
N
H
N
N
O
O
H2C
H2C
TOFP
Compound 1
CH2
CH2
O
O
O
CH2
O
CH2
N
H
N
H
N
N
O
O
H2C
H2C
O
O
H2C
H2C
OOFP
Compound 2
N
H
N
N
H
H
N
N
H
N
N
N
TFP
Compound 3
TPP
Compound 4
OMe
MeO
OMe
OMe
MeO
N
N
H
OMe
N
H
N
H
N
N
H
N
MeO
N
MeO
OMe
OMe
MeO
OMe
TOMePP
Compound 5
OOMePP
Compound 6
Figure 1. Compounds 1, 2, 3, 4, 5, and 6.

S. Drouet et al. / Tetrahedron 65 (2009) 2975–2981
2977
PPh3
NaBH4
O
CBr4
CH2
Br
C
CH2
OH
EtOH
CH2Cl2
0 °C, 1 h
H
r.t., 1 h
7
8
yield 96 %
yield 55 %
Scheme 1. Synthesis of compounds 7 and 8.
the crude product was purified by column chromatography to yield 7
as a white solid (96%). This alcohol was then brominated with carbon
tetrabromide in the presence of triphenylphosphine in dichloro-
methane. The mixture was stirred overnight, concentrated, and pu-
rified by column chromatography to give 2-bromomethyl-fluorene
(8) as a white solid (55%) (Scheme 1).
In the conditions used, the non-substituted fluorene arm is
stable but often alkyl chains have been introduced on the position-
9 of the fluorene units to increase the solubility.8
2.2. Optimized geometries
The two intermediate porphyrins, TOHPP and OOHPP, were
obtained from the methylated porphyrin analogs, porphyrin 5
(TOMePP) and 6 (OOMePP), respectively, by reaction with BBr3.19
meso-(5,10,15,20-Tetra(4-(2-methyloxyfluorenyl)phenyl)porph-
yrin) 1 was obtained by condensation from the prepared bro-
The calculated optimized geometries (‘SPARTAN Pro, Molecular
Mechanics and Quantum Chemical Calculations’, PM3)20 for por-
phyrin derivatives 1 and 2 are shown in Figure 3a and b, re-
spectively. These molecular modeling data clearly show for the new
compound 1 that the trans fluorenyl arms are on the same side of the
porphyrin core, in a alternate way, whereas the macrocyclic core is
essentially planar. Actually, it is known that the meso-aryl groups
are not orthogonal to the porphyrin plane, but slightly tilted,21
allowing the meso group to develop some conjugative interaction
with the main porphyrin framework. Thus, in spite of the large di-
hedral angle between the plane of the phenyl ring and the porphyrin
mide
8 (5 equiv) and TOHPP (1 equiv) in dry THF using
potassium carbonate as base in the presence of 18-crown-6
(Scheme 2). This solution was stirred under argon at reflux for
one day. The reaction time was monitored by UV spectroscopy.
After purification by crystallization, the desired porphyrin 1 was
obtained as a brown-violet solid (95%). meso-(5,10,15,20-Tetra(4-
(3,5-dimethyloxyfluorenyl)phenyl)porphyrin) 2 was obtained by
p
system in the TPP series, conjugation exists to some extent and is
condensation from the prepared bromide
8 (10 equiv) and
affected by the substituents on the phenyl ring. This conjugative
interaction of the aromatic meso-substituents can explain the color
shift observed for various derivatives. Surprisingly, the calculated
optimized geometries showed that the phenyl groups are almost
perpendicular to the porphyrin core for 1. Indeed, the dihedral an-
gles between the phenyl groups and the porphyrin core are 89ꢀ,
whereas for TFP this angle is 64ꢀ, and for TPP 60ꢀ. Similarly the
fluorenyl arms are also perpendicular to the porphyrin core. This
special arrangement gives to the monomer a wheel aspect. So the
interactions between the porphyrin and fluorenyl will be enhanced
OOHPP (1 equiv) in dry THF using potassium carbonate as base
in the presence of 18-crown-6 (Scheme 2). This solution was
stirred under argon at reflux for nine days. Completion of the
reaction time was monitored by UV spectroscopy. After purifi-
cation by column chromatography on silica gel, the desired
porphyrin 2 was obtained as a brown-violet solid (38%).
These new porphyrins 1 and 2 were characterized by NMR, UV–
vis, and mass spectrometry. The hydrogen and carbon atom-label-
ing scheme for the porphyrin ligands 1 and 2 is shown in Figure 2.
D =
O
C
H2
MeO
OMe
Br
H2C
D
HO
D
OH
N
H
BBr3
CH2Cl2
N
H
N
N
N
N
H
K2CO3
N
H
MeO
N
H
N
18-crown-6
H
N
N
N
HO
THF
16 h, Δ
OMe
D
D
OH
TOMePP (5)
TOHPP
TOFP(1)
yield 95 %
OMe
OH
D
OMe
OH
D
Br
H2C
MeO
HO
D
N
H
OMe
OH
N
N
D
N
N
H
H
N
H
H
N
N
N
H
N
N
N
K2CO3
18-crown-6
BBr3
MeO
HO
OMe
OH
D
D
CH2Cl2
THF
9 days, Δ
MeO
HO
D
OMe
OH
D
OOMePP (6)
OOHPP
OOFP (2)
yield 38 %
Scheme 2. Synthesis of A/TOFP: meso-(5,10,15,20-tetra(4-(4-methyloxyfluorenyl)phenyl)porphyrin 1; B/OOFP: meso-(5,10,15,20-tetra(4-(3,5 dimethyloxyfluorenyl)phenyl)porphyrin 2.

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S. Drouet et al. / Tetrahedron 65 (2009) 2975–2981
H6'
C7'
H5'
H4'
C6'
C5'
C5''
H3'
C4'
H7'
C3'
C2'
C4''
C9''
C8'
C8''
HD
CD
C9'
H8'
H2
C2
C1
H3
C4
C1'
H1'
HB
H9'
O
CH
HH
H9''
CB
CA
CE
CD
C3
HH'
D
C20
C19
C5
C6
CB
HB
HD
N
H
C18
C17
C7
C8
N
N
C16
C15
C9
H
N
C10
D
C14
C13
C11
C12
D
Compound 1
H6'
H5'
C6'
C5'
H7'
H4'
C7'
C8'
C5''
C4'
C4''
C9''
H3'
C8''
C3'
C2'
CH
H8'
C9'
H9'
C1'
H9''
HH
H1'
HH'
O
H5'
H6'
H4'
C4'
H2
C2
C1
H3
C3
HB
HE
C6'
CD
C5'
C5''
H3'
CB
CA
CE
CD
C7'
H8'
H7'
C3'
C2'
C4''
C9''
C4
C8'
C8''
D
C20
C5
C6
CB
HB
N
H
O
C9'
C1'
H1'
CH
C19
H9'
C18
C17
C7
C8
H9''
HH'
HH
N
N
C16
C15
C9
H
N
C10
D
C14
C11
D
C13 C12
Compound 2
Figure 2. Hydrogen and carbon atom labeling for the porphyrin ligands 1 and 2.
because the distance is relatively short, around 7–10 Å.20 Similarly
for 2, the phenyl group appears also perpendicular to the porphyrin
core, and the molecular modeling data clearly show for the new
compound 2 that the four fluorenyl arms, on the same side of the
porphyrin core, are disposed like a calix, so the entire molecule
appears as a double calix. In this case the distance between the
porphyrin and fluorenyl arms is short as well. These calculated
conformations are only representative of the prevailing ones, given
that these structures are certainly fluxional in solution. In conse-
quence, other local energy minima might also exist in solution.
2.3. Photophysical properties
2.3.1. Electronic spectra
The UV–vis spectra of 1 and 2 exhibit an intense Soret band with
a maximum absorption similar at around 423 nm (Fig. 4). This band

S. Drouet et al. / Tetrahedron 65 (2009) 2975–2981
2979
Figure 3. (a) Spartan plot of the molecular structure of 1 in comparison to compound 3. (b) Spartan plot of the molecular structure of 2.
is slightly red shifted compared to 417 nm for TPP (4), but not as
much as for TFP (3) (426 nm). This tendency in red shifting is ob-
Notably the fluorene chromophore involved in the UV absorption
process becomes also strongly apparent under such excitation
conditions. For comparison, the excitation spectra of compounds 1
and 2 are shown in Figure 5.
Thus for the new compounds 1 and 2, the luminescence can be
modulated in a large range of excitation wavelengths from UV to
red, to finally obtain the desired red emission.
served as well for the Q bands. The
p–
*
p absorption in the UV range
is clearly apparent, due to the presence of fluorene. For compound
1, the four fluorene arms absorb in the UV range with a maximum
absorption peak at 272 nm, for compound 2 possessing eight arms
the absorption is stronger with a maximum at 263 nm. Finally we
have the following shift for the absorption of the Soret band, for
these compounds:
2.3.3. Fluorescence quantum yields
The fluorescence quantum yields of these compounds were next
determined by comparing with a calibration standard of compound
l3
>
l1
¼
>
l2 l4
2.3.2. Emission
The emission spectrum of compound 1, after excitation in the
Soret band reveals a strong red fluorescence with a peak maximum
at 663 nm and a weak shoulder at 728 nm (Fig. 5). Concerning the
emission spectrum of compound 2, after excitation in the Soret
band, a strong red emission at 656 nm and a shoulder at 721 nm are
observed (Fig. 5). After excitation in bounded-fluorene absorption
(272 nm for compound 1 and 263 nm for compound 2), the emis-
sion spectra reveal red fluorescence and almost no residual emis-
sion of the fluorene for both compounds. Thus, there is apparently
a good energy transfer between fluorene and porphyrin, since es-
sentially red emission of porphyrin is observed in comparison to
blue emission of fluorene at around 300 nm. In fact, almost all the
UV energy absorbed by the fluorine units is emitted by the por-
phyrin core.
1.1
OOFP
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Reference compound TFP
"Reference compound TPP
TOFP
The excitation spectra obtained after exciting in the strongest
emission band at around 660 nm reveal an emission from the Soret
state, the three first Q states, as well as from the fluorene. This
indicates that excitation over all the 200–650 nm region leads to
the population of all the fluorescent excited states of the porphyrin.
240
340
440
540
640
740
Figure 4. UV–vis absorption spectra for compounds 1, 2, 3, and 4, in CH2Cl2 at 25 ꢀ
(2.6ꢁ10ꢂ6 M for TFP, 3 and normalized to the same absorbance for 1, 2, and 4).
C

2980
S. Drouet et al. / Tetrahedron 65 (2009) 2975–2981
3. Conclusion
Emission of compound 2 (OOFP) after excitation at 420 nm
Emission of compound 3 (TFP) after excitation at 425 nm
Emission of compound 4 (TPP) after excitation at 417 nm
Excitation spectrum of compound 2 (OOFP) at 660 nm "
Emission of compound 1 (TOFP) after excitation at 420 nm
Excitation spectrum of compound 1 (TOFP) at 660 nm "
In summary, we have synthesized and characterized two new
porphyrins TOFP, 1, and OOFP, 2, bearing four and eight fluorenyl
pendant arms at the meso-positions, respectively. These two por-
phyrins emit essentially red light after selective UV or visible irra-
diation. In the case of UV irradiation, these systems comprising
a central porphyrin like TPP linked to peripheral photon-harvesting
fluorene moieties have been shown to act as efficient antennas.
Porphyrin TOFP, 1, shows similar emission, in terms of solution-
state fluorescence quantum yield, compared to the reference TPP, 4,
whereas compound OOFP, 2, is slightly enhanced. These results
suggest that a judicious choice of meso-aryl dendrons can allow the
properties of porphyrins to be optimized for OLEDs, both in terms
of efficiency and color tuning. Based on our recent results of anodic
electropolymerization of monomers 3,12 4,27 and 6,28 we now ex-
pect to obtain a polymeric 3D network after connections of the four
or even eight fluorenyl pendant arms. This should allow growing
a polymeric 3D structure from such macrocycle, possessing several
connecting points for each monomer. Compounds 1 and 2 consti-
tute therefore an interesting building block to access new emissive
organic materials.
240
340
440 540
Wavelength (nm)
640
740
Figure 5. Photoluminescence spectra of free ligands 1, 2, 3, and 4 (w1.0ꢁ10ꢂ6 M) in
CH2Cl2 solution, at 25 ꢀC, the emission spectra were cut above 800 nm. Excitation
spectra of compounds 1 and 2.
4 (TPP) in degassed toluene solution presenting a fluorescence
quantum yield of 0.12,22 preferentially to a benzene solution with
a fluorescence quantum yield of 0.1323 (in this latter case, different
refractive indices of the solvents used in the standard and sample
must be corrected).24 In consequence the correction made for the
difference in refractive indices of solvents is in this case not nec-
essary. The quantum yield was calculated from the following
equation:
4. Experimental
4.1. General
All reactions were performed under argon and were magneti-
cally stirred. Solvents were distilled from appropriate drying agent
prior to use, CH2Cl2 from CaH2, CHCl3 from P2O5, and all other
solvents were HPLC grade. Commercially available reagents were
used without further purification unless otherwise stated. 1H NMR
and 13C NMR in CDCl3 were recorded using Bruker 200 DPX, 300
DPX, and 500 DPX spectrometers. The chemical shifts are refer-
enced to internal TMS. The assignments were performed by 2D
NMR experiments: COSY (Correlation Spectroscopy), HMBC (Het-
eronuclear Multiple Bond Correlation), and HMQC (Heteronuclear
Multiple Quantum Coherence). UV spectra were recorded on UVI-
KON XL from Biotek instruments. PL emission was recorded on
a Photon Technology International (PTI) apparatus coupled on an
814 Photomultiplier Detection System, Lamp Power Supply 220B
and MD-5020. Pyrrole and 2-fluorenecarboxaldehyde were pur-
chased from Aldrich and were used as received. Reference:
TFP¼tetrafluorenylporphyrin, TPP¼tetraphenylporphyrin. Purity
of compounds 1 and 2 has been checked by GPC. Size exclusion
chromatography (SEC) of compounds was performed in THF at
20 ꢀC using a Polymer Laboratories PL-GPC 50 plus apparatus (PLgel
2
Fs
¼
FTPP ꢁ ðFs=FTPPÞ ꢁ ðATPP=AsÞ ꢁ ðnTPP=nsÞ
In the above expression, Fs is the fluorescent quantum yield of
the new compound, F is the integration of the emission intensities,
n is the index of refraction of the solution, and A is the absorbance
of the solution at the exciting wavelength. The subscripts TPP and s
denote the reference TPP and unknown samples, respectively.25
Values of quantum yield of free ligands 1, 2, 3 and 4 are reported
in Table 1. All measurements were obtained under an argon at-
mosphere to limit photo-oxidative degradation (Table 1). Com-
pound 2 presents a luminescence quantum yield (13%), which is
similar to that of the reference 4 (12%). Apparently the high
quantum yield (24%) observed for the compound possessing fluo-
rene arms directly connected on the meso positions of TFP is not
maintained when a phenyl intermediate substituted in positions 3
and 5 is introduced. So a system in which a 5,10,15,20-tetraphe-
nylporphyrin (TPP) is linked, via ether bridges, to eight fluorene
donor moieties in positions 3 and 5 presents the same lumines-
cence efficiency as the parent TPP compound. Similarly, compound
1 presents a quantum yield of 10%. Further photophysical in-
vestigations will be undertaken to rationalize these results.26
5
m
m MIXED-C 300ꢁ7.5 mm, 1.0 mL minꢂ1, RI, and Dual angle LS
detector (PL-LS 45/90)).
4.2. Synthesis of the arms
4.2.1. Synthesis of 2-hydroxyl-methyl-fluorene (7)
To a solution of the commercial fluorene-2-carboxaldehyde
(500 mg, 2.57 mmol) in ethanol (40 mL) was added sodium bo-
rohydride (117 mg, 3.09 mmol) at 0 ꢀC for a period of 10 min. The
reaction mixture was stirred at room temperature for 1 h and
then poured into water, followed by extraction with dichloro-
methane. The organic layer was washed with brine, dried over
anhydrous MgSO4, and the solvent was removed. The residue was
purified by column chromatography on silica gel (1:1 CH2Cl2/
Table 1
Photophysical properties of the fluorenyl porphyrins 1, 2, 3 and of TPP, 4, for
comparison
Porphyrin
TOFP (1)
OOFP (2)
TFP (3)
TPP (4)
lmax/nma Soret band
423
663, 728
0.10
423
656, 721
0.13
426
663, 730
0.22
417
653, 721
0.12
lem/nma
Ffb
pentane) to yield 476 mg of
a
white solid (96%). 1H NMR
a
Wavelengths of the absorption and emission maxima in dilute CH2Cl2 solution at
3
3
(200 MHz, CDCl3): 7.81 (d, JHH¼8.0 Hz, 2H), 7.58 (d, JHH¼8.0 Hz,
298 K.
3
b
2H), 7.40 (d, JHH¼10.0 Hz, 2H), 7.33 (s, 1H), 4.80 (s, 2H, CH2–OH),
Fluorescence quantum yields in toluene degassed solution, using TPP as stan-
dard, following excitation into the Soret bands.
3.94 (s, 2H, CH2fluorene).

S. Drouet et al. / Tetrahedron 65 (2009) 2975–2981
2981
3
4.2.2. Synthesis of 2-bromomethyl-fluorene (8)
1H NMR (CDCl3): 8.83 (s, 8H, pyrrole), 7.81 (d, JHH¼7.9 Hz, 8H,
3
0
0
0
To a solution of alcohol 7 (0.5 g, 2.56 mmol) in dichloromethane
(10 mL) was added carbon tetrabromide (936 mg, 2.82 mmol) fol-
lowed by the portion-wise addition of triphenylphosphine
(739 mg, 2.82 mmol). The mixture was stirred at 0 ꢀC for 1 h and
then at room temperature for overnight, concentrated, and purified
by column chromatography on silica gel (9:1 pentane/CH2Cl2) to
give 366 mg (55 %) of 8 as a white solid: 1H NMR (200 MHz, CDCl3):
H4 ), 7.80 (d, JHH¼7.6 Hz, 8H, H5 ), 7.72 (s, 8H, H1 ), 7.55
3
3
0
(d, JHH¼7.4 Hz, 8H, H8 ), 7.54 (s, 8H, HB), 7.52 (d, JHH¼8.0 Hz, 8H,
3
3
0
0
0
H3 ), 7.40 (t, JHH¼7.2 Hz, 8H, H6 ), 7.32 (t, JHH¼7.2 Hz, 8H, H7 ), 7.18
(t, 3JHH¼2.2 Hz, 4H, HE), 5.33 (s, 16H, HH–H ), 3.91 (s, 16H, H9 –9 ).
0
0
00
13C NMR (CDCl3): 157.997 (CD), 147.08 (C1–4–6–9–11–14–16–19),
00
00
00
00
143.939 (CA), 143.73 (C9 ), 142.42 (C8 ), 141.78 (C4 ), 141.32 (C5 ),
135.28 (C2 ), 130.95 (C2–3–7–8–12–13–17–18), 126.91 (C6 ), 126.86 (C7 ),
0
0
0
3
3
0
0
0
0
0
7.81 (d, JHH¼8.0 Hz, 1H), 7.75 (d, JHH¼7.7 Hz, 1H), 7.59 (d,
126.69 (C3 ), 125.18 (C8 ), 124.685 (C1 ), 120.033 (C4 ), 119.975 (C5 ),
3JHH¼8.8 Hz, 2H), 7.43 (d, JHH¼7.9 Hz, 1H), 7.38 (d, JHH¼8.0 Hz,
119.79(C5–10–15–20),115.275(CB),102.87(CE),70.752(CH), 36.904(C9 ).
3
3
0
1H), 7.37 (s, 1H), 4.91 (s, 2H, CH2–Br), 3.94 (s, 2H, CH2fluorene).
Analysis: calcd for C156H108N4O8$2CH3CO2Et: C, 84.08; H, 5.33;
N, 2.39; found: C, 84.62; H, 6.03; N, 1.57, MALDI TOF-MS calcd for
C156H108N4O8: 2166.550 [MH]þ, found 2166.596 [MH]þ.
UV–vis (CH2Cl2): lmax/nm 270 (fluorene, 3270¼141700), 292
(fluorene, 32912¼64 600), 304 (fluorene, 3304¼71000), 423 (Soret
band, 3423¼245 300), 516 (Q1 band, 3516¼10 700), 551 (Q2 band,
3551¼2200), 592 (Q3 band, 3592¼2200) and 653 nm (Q4 band,
3653¼4600).
4.3. Synthesis of the porphyrins
4.3.1. Synthesis of porphyrin 1
TOFP, meso-(5,10,15,20-tetra(4-(2methyloxyfluorenyl)phenyl)-
porphyrin), 1: 2-bromomethyl-fluorene (191 mg, 736
kis (4-hydroxyphenyl)-porphyrin TOHPP (100 mg, 147
K2CO3 (162 mg, 1.18 mmol), and 18-crown-6 (40 mg, 67 mol) were
m
mol), tetra-
mmol),
Acknowledgements
m
dissolved in 10 mL of dry THF and stirred under argon at reflux for
16 h. The reaction mixture was cooled to room temperature and the
mixture was filtrated. The insoluble violet powder was washed
with THF (100 mL), water (100 mL), and pentane (100 mL). The
precipitate was dried over MgSO4 and in oven (50 ꢀC) under vac-
uum to yield a violet solid (95%). The purity of compound 1 has
been checked by TLC plate and by GPC (SEC).
The authors are grateful to K. Kostuas (CTI-UMR 6226), S. Sin-
bandhit (CRMPO), and P. Le Maux (ICMV-UMR 6226) for their
technical assistance and helpful discussions.
Supplementary data
1H NMR (solubilized by acidic deuterated TFA in CDCl3): 8.54
Supplementary data associated with this article can be found in
the online version, at doi:10.1016/j.tet.2009.02.015.
(d, 3JHH¼8.4 Hz, 8H, HB), 8.52 (s, 8H, pyrrole), 7.96 (d, 3JHH¼7.8 Hz, 4H,
3
0
0
0
H4 ), 7.90 (d, JHH¼7.4 Hz, 4H, H5 ), 7.87 (s, 4H, H1 ), 7.68
3
3
References and notes
0
(d, JHH¼7.8 Hz, 4H, H3 ), 7.65 (d, JHH¼8.4 Hz, 8H, HD), 7.64
3
3
0
0
(d, JHH¼7.3 Hz, 4H, H8 ), 7.46 (t, JHH¼7.6 Hz, 4H, H6 ), 7.38
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(t, 3JHH¼7.4 Hz, 4H, H7 ), 5.52 (s, 8H, HH-H ), 4.06 (s, 8H, H9 -9 ).
0
0
0
00
13C NMR (solubilized by acidic deuterated TFA in CDCl3): 160.82
00
00
(CE), 146.04 (C1–4–6–9–11–14–16–19), 144.18 (C9 ), 143.31 (C8 ), 142.18
00
00
0
(C4 ), 141.13 (C5 ), 140.01 (CB), 133.53 (CA), 134.86 (C2 ), 127.84 (C2–3–
0
0
0
0
7–8–12–13–17–18), 127.03 (C7 ), 126.91 (C6 ), 126.69 (C3 ), 125.18 (C8 ),
0
0
0
124.69 (C1 ), 122.10 (C5–10–15–20), 120.11 (C5 ), 120.20 (C4 ), 114.95
0
(CD), 70.97 (CH), 37.02 (C9 ).
Analysis: calcd for C100H70N4O4$1.5CHCl3: C, 77.02; H, 5.32; N,
3.54; found: C, 77.44; H, 4.76; N, 3.37. MALDI TOF-MS: calcd for
C100H70N4O4: 1390.5500 [MH]þ, found 1390.3650 [MH]. UV–vis
(CH2Cl2): lmax/nm 263 (fluorene, 3263¼74 800), 291 (fluorene,
3291¼45 000), 304 (fluorene, 3304¼53 200), 423 (Soret band,
3423¼213 600), 516 (Q1 band, 3516¼14 800), 551 (Q2 band,
3551¼11400), 590 (Q3 band, 3590¼8200) and 647 nm (Q4
band, 3647¼11400). UV–vis (0.02 mL TFA/1 L CH2Cl2): lmax/nm
263 (fluorene, 3263¼105 600), 291 (fluorene, 3291¼53 200), 304
(fluorene, 3304¼63 000), 451 (Soret band, 351¼373 000), 682
(Q1 band, 3682¼58 600), 700 (Q3 band, 3700¼41000).
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4.3.2. Synthesis of porphyrin 2
OOFP,
phenyl)porphyrin),
606
mol), tetrakis (30,50-dihydroxyphenyl)-porphyrin OOHPP
meso-(5,10,15,20-tetra(4-(3,5dimethyloxyfluorenyl)-
2: 2-bromomethyl-fluorene (157 mg,
m
(50 mg, 67
(18 mg, 67
m
mol), K2CO3 (149 mg, 1.07 mmol), and 18-crown-6
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under argon at reflux for 9 days. The reaction mixture was cooled to
room temperature, and the mixture was poured in a separatory
funnel containing 50 mL of CH2Cl2 and washed with water
(100 mL) twice and brine (100 mL). The organic phase was dried
over MgSO4 and the solvent was removed. The residue was purified
by column chromatography on silica gel (9:1 CH2Cl2/pentane) to
yield 56 mg of a brown solid (38%). The purity of compound 2 has
been checked by TLC plate after column chromatography and by
GPC (SEC).
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