A family of fluorenyl dendrons for porphyrin dendrimers synthesis

Article abstract of DOI:10.1016/j.tet.2012.07.018

A series of dendrons bearing various number of fluorenyl donor groups have been synthesized. First, the reference compound 2-(bromomethyl)-9H-fluorene (8) with one fluorenyl unit, then dendron 10, with two fluorenyl arms, and finally new generation dendro

Full text of DOI:10.1016/j.tet.2012.07.018

Tetrahedron 68 (2012) 7901e7910
Contents lists available at SciVerse ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
A family of fluorenyl dendrons for porphyrin dendrimers synthesis
a
,
b
a
a
a,b,
*
Areej Merhi , Samuel Drouet , Nicolas Kerisit , Christine O. Paul-Roth
a
Institut des Sciences Chimiques de Rennes, ISCR-UMR CNRS 6226, Universit ꢀe de Rennes 1, 35042 Rennes Cedex, France
Institut National des Sciences Appliqu ꢀe es, INSA-ISCR, Universit ꢀe Europ ꢀe enne de Bretagne, 35043 Rennes Cedex, France
b
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 4 May 2012
Received in revised form 6 July 2012
Accepted 8 July 2012
Available online 16 July 2012
A series of dendrons bearing various number of fluorenyl donor groups have been synthesized. First, the
reference compound 2-(bromomethyl)-9H-fluorene (8) with one fluorenyl unit, then dendron 10, with
two fluorenyl arms, and finally new generation dendrons, 11 and 12, bearing four peripheral fluorenyl
arms were synthesized and characterized. A series of different generations of porphyrin dendrimers,
obtained from these dendrons are also presented. Preliminary results on higher generation dendrimers
are reported as well. Under mild basic conditions, surprisingly, a new compound 1 incorporating a flu-
orenyl unit in the cycle and three pendant fluorenyl arms was obtained by an intramolecular reaction of
brominated tetrapod dendron 12.
Ó 2012 Elsevier Ltd. All rights reserved.
1. Introduction
Light Emitting Diodes (OLEDs).15,16 Also, new supramolecular as-
semblies using these efficient building blocks have been prepared
1
7
Porphyrin systems are very interesting because the peripheral
substituent on the macrocyclic core can modulate the physical
properties at will. Such systems present wide potential applications
in different fields: such as for instance Organic Light Emitting
Diodes (OLEDs), light-harvesting antenna or photonic switches.
Light-harvesting can be optimized by connecting four energy donor
and studied by our group.
In this report, another way to use fluorenyl-based antenna with
systems like TFP will be considered. Earlier, we described efficient
systems in with 5,10,15,20-tetraphenylporphyrin (TPP), linked, via
ether bridges, to 4, 8 and 16 fluorenyl donor moieties, compounds
2, 3 and 4, respectively (Fig. 1). After the successful synthesis of
these porphyrin-fluorenyl dendrimers, we wondered about higher
generation compounds. Indeed, starting from new dendrons, a new
dendrimer with 32 fluorenyl donor moieties (32F) can be designed.
However, in this respect, the synthesis of higher generation den-
drons was required. To this aim new dendrons with four peripheral
fluorenyl groups (11 and 12) are described and compared to the
18
19
1
e3
dendrons to the porphyrin core, to obtain an antenna system.
Recently, following such a scheme, a series of porphyrins bearing
4
,5
pendant linear oligofluorenyl arms have been reported. In this
6
connection, Fr eꢀ chet had demonstrated that the antenna effect was
facilitated in dendritic architectures versus the corresponding lin-
ear case and reported the synthesis of porphyrin systems with
modified fluorenyl units as light-harvesting two-photon absorbing
chromophores.7 The same year, the synthesis of hyperbranched
polymers containing porphyrin with fluorenyl arms has also been
reported.9
dendrons with two units (9 and 10), reported earlier by our
Results are reported and compared to previous data in
order to better understand the reactivity of the new brominated
,8
18,19
group.
tetrafluorenyl dendron 12.
On our side, we have previously reported the synthesis of por-
phyrin possessing four fluorenyl arms directly connected at the
2
2
. Results and discussion
.1. Synthesis
10e13
meso-positions (TFP, compound 5).
More recently, a complete
family of relevant porphyrins was studied in collaboration with
Williams.14 Surprisingly, TFP exhibited a remarkably high quantum
yield (24%), demonstrating the capacity of the fluorenyl units to
enhance quantum yields. Logically, we next tested the corre-
sponding platinum(II) complex in the fabrication of red Organic
The synthetic strategy developed for the preparation of these
20
porphyrin-fluorenyl dendrimers is a Frechet’s style condensation.
First, we will present rapidly the already described synthesis of
dendrons 8, 9, 10 and in more detail, the synthesis of new dendrons
11 and 12. In a second time, the synthesis of an intermediate por-
phyrin 7, possessing anchoring points is reported. Then, the pre-
vious dendrons 8 and 10 are connected to porphyrin macrocycle to
obtain the dendrimeric porphyrins 2, 3 and 4, as described earlier
*
Corresponding author. Tel.: þ33 (0)2 23 23 63 72; fax: þ33 (0)2 23 23 56 37;
e-mail addresses: christine.paul@univ-rennes1.fr, christine.paul@insa-rennes.fr
C.O. Paul-Roth).
(
0
040-4020/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2012.07.018

7902
A. Merhi et al. / Tetrahedron 68 (2012) 7901e7910
O
O
O
O
O
O
Compound 1
CH
2
CH
2
O
O
CH
2
CH
2
O
O
O
CH
2
O
N
CH
2
N
N
O
N
H
N
H
H
N
N
N H
O
H
2
C
H
C
2
O
O
H
2
C
H C
O
2
O
H
2
C
2
H C
OOFP
TOFP
Compound 3
Compound 2
O
O
O
O
O
2
H C
O
CH
2
O
O
O
CH
2
O
O
2
H C
N
O
N
H
H
N
N
O
O
CH
O
2
2
H C
O
O
O
O
O
H
2
C
O
2
H C
O
O
O
SOFP
Compound 4
Ar
Ar
Ar
Ar
Ar
N
N
H
H
Ar
N
N
H
N
H
N
N
Ar
N
Ar
Ar
Ar
Ar
OMe
Ar
Ar =
Ar =
TFP (Compound 5)
OOMePP (Compound 6)
OOHPP (Compound 7)
TPP
OH
Fig. 1. Compounds 1, 2, 3, 4, 5, 6 and 7.

A. Merhi et al. / Tetrahedron 68 (2012) 7901e7910
7903
by our group.18,19 Preliminary results on higher generation den-
drimer syntheses are reported; in this case, eight of these new
dendrons 12 are tried to be connected by Williamson reactions, to
porphyrin 7.
yield. New dendrons 11 and 12 were fully characterized, the hy-
drogen and carbon atom-labelling schemes for these dendrons 11
and 12 are shown in Fig. 3.
2
.1.2. Synthesis of macrocycle. In this second part, different gener-
ations of porphyrin dendrimers are synthesized using convergent
strategy. First, the intermediate porphyrin (OOHPP), was
obtained from the prepared methylated porphyrin analogue, por-
2.1.1. Synthesis of dendrons. The 2-hydroxyl-methyl-fluorene was
obtained by reduction of commercial fluorene-2-carboxaldehyde
and the corresponding alcohol was then brominated with carbon
7
1
8
tetrabromide to obtain 2-bromomethyl-fluorene 8 (Scheme 1).
phyrin 6 (OOMePP) by reaction with BBr
3
as illustrated in
21
Next, the alcoholic form of the dendron 9 was obtained by
condensation from the previous prepared bromide 8 and com-
mercial 5-hydroxymethyl-benzen-1,3-diol, in basic conditions
Scheme 4.
The small dendrimer 3, generation
1
G , containing eight
absorbing donor chromophores was obtained by condensation
(Scheme 2).
from the prepared bromide 8 (10 equiv) and porphyrin 7 (1 equiv)
PPh
CBr
3
4
NaBH4
O
C
CH
2
EtOH
CH Cl
2
2
Br
H
OH
r.t., 1 h
8
0°C, 1 h
Yield 96 %
Yield 55 %
Scheme 1. Synthesis of compound 8.
OH
OH
K CO
18-crown-6
2
3
O
O
HO
HO
acetone (12h)
Yield 71 %
Br
9
8
O
O
O
PPh
3
CBr
4
HO
THF
Br
O
0
°C, 1 h
Yield 80 %
9
1
0
Scheme 2. Synthesis of dendrons 9 and 10.
Thus, the dendron 9 was obtained pure as a white solid after
in dry THF using potassium carbonate as base in presence of
purification in 71% yield. This alcohol 9 was then brominated with
carbon tetrabromide in THF and the final dendron 10 was obtained
pure as a white solid after flash chromatography in 80% yield. The
18-crown-6. After purification, 3 was obtained as a brown-violet
18
solid (38%) as already described. For clarity, characterization by
NMR is reported; the hydrogen and carbon atom-labelling scheme
for this porphyrin 3 is shown in Fig. 4.
19
detailed synthesis of these building blocks was described earlier,
but for clarity characterization by NMR is reported; the hydrogen
and carbon atom-labelling schemes for compounds 9 and 10 are
shown in Fig. 2.
The new tetrapod dendron 11 was synthesized by condensation
from the previous prepared bromide 10 and 5-hydroxymethyl-
benzen-1,3-diol in acetone using potassium carbonate as a base in
presence of 18-crown-6 (Scheme 3).
Finally, the dendron 11 was obtained pure as a white solid after
purification in 70% yield. This alcohol 11 was then brominated with
carbon tetrabromide in THF and the new desired dendron 12 was
obtained pure as a white solid, after flash chromatography in 70%
2
The larger dendrimer 4, generation G , containing 16 chromo-
phores was synthesized from dendron 10 (10 equiv) and porphyrin
7 (1 equiv) in the same conditions as before. Compound 4 was thus
19
obtained as a brown-violet solid (33%) as described, and for clarity,
characterization by NMR is reported. The hydrogen and carbon
atom-labelling scheme for this porphyrin 4 is shown in Fig. 5.
It should be noted that in the conditions used, the non-
substituted fluorenyl arm is stable but alkyl chains have often
been introduced on the position-9 of the fluorenyl units to increase
5
their solubility. This is presently not necessary for compounds 3
and 4; they are very soluble and stable.

7904
A. Merhi et al. / Tetrahedron 68 (2012) 7901e7910
Fluorenyl
H4'
H5'
O
H3'
H6'
CD'
C4'
C5'
HB'
HE'
C3'
C2'
C1'
C6'
X= OH Compound 9
X= Br Compound 10
CB'
CE'
C4'' C5''
C7'
CA'
HH1
CD'
H
O
C9''
C8'
CB'
C
C8'
H8'
7'
C9'
'
HH'1
HH2
X
HH'2
H9'
H1'
H9''
Fig. 2. Hydrogen and carbon atom-labelling for dendrons 9 and 10.
OH
HO
O
OH
K2CO3
+
O
1
8-crown-6
acetone (15h)
Yield 70 %
O
O
O
Br
HO
O
O
10
O
O
11
O
O
O
PPh
3
CBr
4
O
O
HO
O
O
THF
O
0
°C, 48 h
Br
O
11
Yield 70 %
O
O
12
Scheme 3. Synthesis of dendrons 11 and 12.
Fluorenyl
H6'
H5'
H4'
O
C C6'
5
'
H3'
HE'
C4'
HB'
CD'
CB'
C
H
7'
C5''
7'
CB'
CA'
C3'
C2'
C4''
C9''
CE'
C8''
C
8'
HH1
CD'
X= OH Compound 11
X= Br Compound 12
C9'
H8'
O
C1'
C
H9'
HH'1
O
HH2
H9''
HB'
H
HH'2 1'
HB''
CD''
CB''
HE''
CE''
CD''
O
Fluorenyl
CA''
HH11
CB''
O
HH'1
1
H
B''
X
Fluorenyl
O
Fig. 3. Hydrogen and carbon atom-labelling for dendrons 11 and 12.
Preliminary results on the syntheses of a higher generation
porphyrin dendrimer (G are reported. Synthesis of 32F
Scheme 4), containing thirty-two chromophores, was tried, and
in this case, eight of new dendrons 12 should be attached to
porphyrin 7. For this synthesis, a mixture of 10 equiv of bromide
12 and 1 equiv of 7 in dry THF, using potassium carbonate as
a base, in presence of 18-crown-6 was reacted (Scheme 4). Re-
action progress is monitored by TLC, spotting directly from the
3
)
(

A. Merhi et al. / Tetrahedron 68 (2012) 7901e7910
7905
OMe
OH
OMe
OH
OH
MeO
HO
NH
OMe
NH
OH
BBr3
N
N
N
N
NH
NH
MeO
OMe
HO
CH Cl2
2
Yield 93 %
OMe
MeO
OH
HO
OOHPP (7)
OOMePP (6)
D
OH
OH
OH
D
HO
D
NH
OH
NH
D
N
N
N
NH
N
NH
HO
K CO
D
2
3
D
1
7
8-crown-6
OH
HO
OOHPP (7)
+
THF
days,
D
D
Porphyrin 32F
O
O
O
H
2
C
O
O
Br
O
O
O
H C
2
D =
O
O
O
O
Dendron 12
O
Scheme 4. Synthesis of porphyrin-intermediate 7 and attempt to synthesis porphyrin 32F.
organic layer. The fixation of a various number of donor chro-
mophores was confirmed by proton NMR, but total fixation of all
eight donor chromophores 12 was not observed. The desired
porphyrin 32F was not extracted from the crude, only a mixture
of differently substituted porphyrin dendrimers (yield around
It is known that above a certain dendrimer size, a limiting
generation is reached beyond, which a dendrimer of perfect
structure is no longer possible. Attainment of the limiting genera-
tion in dendrimer growth is considered as a result of the starburst
limit effect, due to steric hindrance during formation of the den-
2
2
4
0%).
drimer. The starburst point occurs at a well-defined limit for each
Fluorenyl
O
H5'
C5'
H6'
H2
H3
C4
H
4'
HB
CD
HE
H3'
C
6'
C2 C3
CB
CE
C
4'
C5''
C
7'
H7'
C3'
C2'
C4''
C9''
C1
CA
CD
D
C
8''
C
8'
C20
C19
C5
C6
CB
HB
N
H
O
C
C1'
9'
H8'
CH
H9'
C18
C7
C8
H9''
HH' H1'
HH
N
N
C17
C16
C15
C9
H
N
C
10
D
C
14
C
11
D
C13 C12
Compound 3
Fig. 4. Hydrogen and carbon atom-labelling for porphyrin 3.

7906
A. Merhi et al. / Tetrahedron 68 (2012) 7901e7910
Fluorenyl
O
Fluorenyl
O
O
Fluorenyl
H
2
H
3
O
H
B
H
B'
C
D
H
E
C
H
4'
H
5'
C
D'
B'
C
2
C
3
C
B
A
C
E
HH1
H3'
H6'
C
E' HE'
C
4'
C
5'
C
A'
C
3'
C
6'
C
1
C
4
C
C
D
D
C4''
C
C
B'
C
D'
5''
C
20
19
N
H
C
5
C
B
O
HH'1
C
2'
C
7'
O
H7'
C
9''
C8'
C
C
6
H
B
C
C1'
C8'
C
18
17
C
7
8
H
H2
C9'
'
N
N
H
H'2
H
1'
H9'
H
8'
C
C
H
9''
C
16
C
9
H
N
C
15
C
10
D
C
14
C
11
D
C
13
C
12
Compound 4
Fig. 5. Hydrogen and carbon atom-labelling for porphyrin 4.
dendrimer system,23 in our case, this point is probably reached for
dendrimer G
this unit. For our project, due to the encouraging results obtained
for synthesis of lower generation dendrimers (G , G and G ), and
a lack of space in the desired dendrimeric species 32F (G ), this was
3
.
0
1
2
Nevertheless, we observed that in the basic conditions used
Scheme 4), one of the protons in position-9 of the non-substituted
3
(
voluntary avoid. Surely, the presence of alkyl chains will prevent
5
fluorenyl arms (compound 12), can react. The non-protected car-
bon, in position-9, will in an intramolecular way, react with the
bromomethyl group to form new compound 1 incorporating a flu-
orenyl unit in the cycle and three pendant fluorenyl arms. Com-
pound 1 was obtained as a pale yellow solid (52%), very soluble in
most organic solvents and can be purified by precipitation (THF,
heptane). Compound 1 is well-behaved in silica gel chromatogra-
phy and was fully characterized by usual solution spectroscopies
the formation of compound 1, but will not favour the formation of
3
higher generation G .
2.2. NMR studies
The 1H NMR signals obtained in deuterated chloroform for
dendrons 11 and 12 are fine and well resolved. For these two
dendrons, there is only a clear difference in shift for the protons in
(
NMR and mass spectrometry) and microanalysis. For clarity,
the CH group for the bromide ligand 12, CH eBr:
d
¼4.38 ppm and
2
2
characterization by NMR is reported; the hydrogen and carbon
atom-labelling scheme for compound 1 is shown in Fig. 6.
As reminded earlier, alkyl chains are often introduced in
position-9 of the fluorenyl, to increase the solubility and stability of
for and the corresponding alcohol 11, CH
2
eOH at d
¼4.59 ppm. The
other proton signals are quite similar.
1
The H NMR signals obtained in deuterated chloroform for
compound 1, are fine and well resolved. A clear difference in shift is
HH2
HH2'
Fluorenyl
H5'
H6'
H4'
C4'
O
C C
'
6'
5
HB'
H3'
HE'
CD'
CB'
C3'
C2'
C
5''
C7' H7'
CE'
C4''
C9''
HH1
CA'
CB'
C C
8'' 8'
CD'
O
O
H
C1'
C9'
H
H8'
H'1
C
HB''
CD''
H
H2
H1'
HH'2
H9'
CB''
CA''
E''
HB'
H9''
CE''
HH'11
C
H1
HH11
D''cycle
B''cycle
C
O
H8
H7
H '
1
HB''cycle
Bcycle
C7 C8
H6 C6
C5
H H
9
HEHH2HH2'
C9
H
1
Fluorenyl
O
O
H5
C1
HB
H4 C4
C3
Compound 1
H3
HG
HF
Fig. 6. Hydrogen and carbon atom-labelling for new compound 1 incorporating a fluorenyl unit in the cycle (in pink) and three pendant fluorenyl arms (in blue).

A. Merhi et al. / Tetrahedron 68 (2012) 7901e7910
7907
observed for the tetrapodal ligand 12 when free and in the corre-
sponding tripodal cyclic compound 1 (Fig. 7). The latter is induced
by the very close proximity of the benzyl groups shielding cone of
the proton in the newly formed cycle.
probably due to proximity to shielding cone of benzyl groups in
the cycle.
In addition, we can notice that all the seven peripheral protons
on the three non-cyclized fluorenyl arms are equivalent, and in
1
For example, the H NMR spectrum of 1 reveals that the three
expected position: 7.80 (H
(H ), 7.43e7.37 ( H and H
4
0
), 7.78 (H ), 7.33
0
5
0
), 7.59 (H
8
0
), 7.56 (H
3
0
1
H resonances for proton in the position-9 of the fluorenyl (H
9
-
7
0
1
0
6
). In the opposite, the proton H (bold
1
triplet) and CH
2
units (HH11 and H 11-doublet), are significantly
H
0
in Fig. 6), on the cyclized fluorenyl group, is shifted to 6.44 ppm, so
with an important up field of Dd¼ꢀ1.0, as before, due to be located
within the shielding cone of benzyl groups (benzyl group in bold
blue and brown in Fig. 6). Whereas all the six other peripheral
protons on the cyclized fluorenyl are in expected positions:
7.72e7.62 (m, 3H, H5e6e8) and 7.44-7.36 (m, 3H, H3e4e7).
up field of their positions in tetrapod ligand 12, as expected for
protons located within the shielding cone of benzyl groups
(
benzyl group in bold blue and brown, in Fig. 6). This effect is
particularly important for H
(bold in Fig. 6) with Dd¼ꢀ1.8 but
weaker for HH11 and H
11 (bold in Fig. 6), with Dd¼ꢀ0.4 and
unit responsible for
9
0
H
Dd¼ꢀ0.7, these protons being on the CH
2
closing the cycle. These signals are also broader and less re-
2.3. Photophysical properties
solved, in line with the highly fluxional nature of the ligand at
ambient temperature. Similar shift is observed for H
B
00cycle
(
d
at
2.3.1. Electronic spectra. The UVevisible spectra of 2, 3 and 4 ex-
6
.02 ppm) but not for HBcycle at 6.39 ppm), this difference is
(
d
hibit an intense Soret band with a maximum absorption similar
Fig. 7. 1H NMR studies (in CDCl
3
2 2
) of free dendron 12 in comparison to compound 1 (on the top with a CH Cl pic), showing the shift for the cyclic fluorenyl as indicated by the
arrows.

7908
A. Merhi et al. / Tetrahedron 68 (2012) 7901e7910
around 423 nm (Fig. 8a). This band is slightly red shifted compared
to 417 nm for TPP, but not as much as for TFP (426 nm). This ten-
exploiting the antenna effect between peripheral units and the
central core. Effectively, for this effect, it is better to have a multi-
component structure in which the donors and acceptors retain
their individual characteristics. Consequently, for an optimization
of this photosynthetic antenna function, a higher generation
porphyrin-based model system was tried. In this goal tetrapodal
dendron 12 was synthesized. In the same conditions, and same
concentration as dendron 10, as expected, the absorption of new
dendron 12 is strongly exalted in comparison to bipodal dendron 10
(Fig. 8b).
3. Conclusions
In summary, a series of dendrons bearing fluorenyl donor
groups were presented. Successively, compound 8: bearing one
fluorenyl, compound 10: with two fluorenyl units, and finally new
dendrons 11 and 12, bearing four peripheral fluorenyl arms were
synthesized and fully characterized. Then, a series of porphyrin
dendrimers (generation G
dendrons are presented, namely: 2, 3 and 4. However, the synthesis
of a higher generation porphyrin (G ), bearing thirty-two fluorenyl
0 1 2
, G and G ) bearing these fluorenyl
3
arms (called 32F), from the new tetrapod dendron 12 failed. Most
likely the so called ‘starburst limit effect’ was reached here. Nev-
ertheless, in the course of these trials, an interesting compound 1,
incorporating a fluorenyl unit in the cycle and three pendant flu-
orenyl arms, was obtained and fully characterized. It is probably
formed by an intramolecular reaction of the brominated dendron
12.
4
4
. Experimental section
.1. General procedures
All reactions were performed under argon and were magneti-
cally stirred. Solvents were distilled from appropriate drying agent
prior to use, CH Cl from CaH , CHCl from P and all other sol-
2
2
2
3
2 5
O
vents were HPLC grade. Commercially available reagents were used
1
without further purification unless otherwise stated. H NMR and
Fig. 8. (a) Absorption spectra of TPP (red), 5 (pink), 2 (blue), 3 (dark blue) and 4
13
(
green) in chloroform at room temperature. All the spectra are normalized to the
3
C NMR in CDCl were recorded using Bruker 200 DPX, 300 DPX
ꢀ
6
spectrum of the reference TPP at 417 nm (concentration w2.0ꢁ10 M). (b) Absorption
spectra of 6 (red), 10 (blue), 12 (pink) and 4 (green) in chloroform at room temperature.
The spectrum of 10 is normalized to the spectrum of 4 at 300 nm, while the height of
the Soret band at 420 nm in the spectrum of 6 is normalized to the height of the Soret
and 500 DPX spectrometers. The chemical shifts are referenced to
internal TMS. The assignments were performed by 2D NMR exper-
iments: COSY (Correlation Spectroscopy), HMBC (Heteronuclear
Multiple Bond Correlation) and HMQC (Heteronuclear Multiple
Quantum Coherence). UV spectra were recorded on UVIKON XL
from Biotek instruments. PL emission was recorded on a Photon
Technology International (PTI) apparatus coupled on an 814 Pho-
tomultiplier Detection System, Lamp Power Supply 220B and
MD-5020. Melting points were measured on Leica VMHB apparatus
with a System Kofler. Pyrrole and 2-fluorenecarboxaldehyde were
purchased from Aldrich and were used as received. References
TFP¼tetrafluorenylporphyrin and TPP¼tetraphenylporphyrin.
band of 1. The spectrum of 12 is at the same concentration as dendron 10
6
(
w2.0ꢁ10ꢀ M).
dency in red shifting is observed as well for the Q-bands. The pep
*
absorption in the UV range is clearly apparent, due to the presence
of fluorenyl arms. For compound 2, the four fluorenyls absorb in the
UV range with a maximum absorption peak at 272 nm, while for
compound 3 possessing eight arms, the absorption is stronger with
2
a maximum at 263 nm. For the generation G , super porphyrin 4;
we can notice that the absorption in the UV of the fluorenyl groups
at 270 nm is as strong as the Soret band, as illustrated in Fig. 8a.
Consequently, it is important for light-harvesting optimization to
4.2. Synthesis of the dendrons
4.2.1. Synthesis of 2-(bromomethyl)-9H-fluorene (8). Synthesis of
2-(bromomethyl)-9H-fluorene (8) from prepared 2-(hydrox-
3
try to access to higher generation G , porphyrin dendrimer.
1
8 1
Fig. 8b shows the absorption spectra of dendron 10 possessing
two fluorenyl units, the porphyrin core with 8 anchoring points,
and the porphyrin possessing 16 fluorenyl arms 4 is again reported.
The absorption spectrum of 4 shows the characteristic peaks at 280
and 300 nm of dendron 10 in addition to the porphyrin Soret band
at 423 nm and less intense Q-bands, the first of which appears at
ymethyl)-9H-fluorene was described earlier.
H NMR (200 MHz,
3
3
CDCl
3
,
d
in ppm): 7.81 (d, JHH¼8.0 Hz,1H), 7.75 (d, JHH¼7.7 Hz, 1H),
3
3
7.59 (d,
J
HH¼8.8 Hz, 2H), 7.43 (d,
J
HH¼7.9 Hz, 1H), 7.38 (d,
eBr), 3.94 (s, 2H,
3
J
HH¼8.0 Hz, 1H), 7.37 (s, 1H), 4.61 (s, 2H, CH
2
CH2fluorene).
5
13 nm. Obviously, the dendron 10 and the porphyrin core retain
4.2.2. Synthesis of alcohol 9. Synthesis of alcohol 9 from prepared
18 1
their individual characteristics. These considerations indicate that
this molecular pentad 4, in which the porphyrin acceptor is linked,
via spacers, to donor dendrons, forms a suitable choice for
2-(bromomethyl)-9H-fluorene (8) was described earlier. H NMR
3
(200 MHz, CDCl
3
,
d
in ppm):
d
7.81 (d, JHH¼7.5 Hz, 4H, H
4 5
- ), 7.64
0 0
3
(s, 2H, H ), 7.57 (d,
1
0
J
HH¼7.1 Hz, 2H, H ), 7.46-7.26 (m, 6H,
0
8

A. Merhi et al. / Tetrahedron 68 (2012) 7901e7910
7909
H
4
3
0
e6
0
e7
0
), 6.69 (br s, 2H, H
B
0
) 6.63 (br s, 1H, H
0
E
0
), 5.15 (s, 4H, H2e2
0
),
eluent. The expected compound tetrafluorenyl dendron 12, was
obtained as a yellow powder to yield 60 mg (70%). This new
dendron 12 was characterized by NMR, UVevisible, microanalysis
3
.68 (d, JHH¼3.7 Hz, 2H, H1e1 ), 3.95 (s, 4H, H
9
0
e900).
1
4
.2.3. Synthesis of bromide dendron 10. We describe here briefly
and mass spectrometry. H NMR (300 MHz, CDCl
3
,
d
in ppm): 7.79
18
3
3
the synthesis of bromide dendron 10 from alcohol (9). To a THF
solution (100 mL) of alcohol 9 (1.60 g, 3.22 mmol), was added
carbon tetrabromide (1.28 g, 38.7 mmol) followed by the portion-
wise addition of triphenylphosphine (1.01 g, 38.7 mmol). The
mixture was stirred at 0 C for 1 h, and 2 h at room temperature.
The crude product was partitioned between water (to neutralize
CBr
evaporated to dryness. The residue was purified by column chro-
matography on silica gel (5:1 pentane/CH Cl ) to give 1.44 g (80%)
of 10 as a white solid. H NMR (200 MHz, CDCl in ppm): 7.81
(d, 4H, H
4
0
, JHH¼7.5 Hz), 7.77 (d, 4H, H
5
0
, JHH¼7.5 Hz), 7.61 (s, 4H,
3
3
H
1
0
), 7.55 (d, 4H, H
7.39 (t, 4H, H
8
0
,
J
HH¼7.2 Hz), 7.42 (d, 4H, H
3
0
,
J
HH¼7.6 Hz),
, JHH¼7.2 Hz), 6.72 (d,
HH¼2.3 Hz), 6.62 (d, 2H,
00, JHH¼2.3 Hz), 5.12 (s, 8H, OCH
), 4.38 (d, 2H, CH eBr,
, JHH¼5.7 Hz), 3.89 (s, 8H, CH2fluorene, H
-900). Anal. Calcd
59BrO $4CH Cl : C, 64.97; H, 4.72; N, 0.00. Found: C,
65.72; H, 4.28; N, 0.00. MS (ESI): calcd for 59BrO
3
3
0
, JHH¼7.6 Hz), 7.32 (t, 4H, H
0
7
6
3
3
4H, H
B
0
,
J
HH¼2.1 Hz), 6.66 (t, 2H, H
0
, J
E
ꢂ
3
3
H
H
H
B
00, JHH¼2.1 Hz), 6.55 (t, 1H, H
E
2
,
0
), 4.98 (s, 4H, OCH
, HH1eH1
0
H2eH2
H11eH11
2
2
3
) and CH
2
Cl
2
, and the organic phase was dried over MgSO
4
and
0
0
9
4
for C77
H
6
2
2
2
2
C
77
H
6
:
1
þ
þ
3
,
d
3
1181.33927 [MNa] , found 1181.33860 [MNa] . Melting point:
3
ꢂ
(
d, JHH¼7.5 Hz, 4H, H
4
0
e5
0
), 7.63 (s, 2H, H
1
0
4
), 7.57 (d, JHH¼7.2 Hz, 2H,
126.0 C.
H
8
0
4
), 7.45e7.26 (m, 6H, H
3
0
e6
0
e7
0
), 6.71 (d, JHH¼2.1 Hz, 2H, H
B
0
), 6.63
), 3.94
(
(
t, JHH¼2.1 Hz, 1H, H
E
0
), 5.13 (s, 4H, H2e2 ), 4.46 (s, 2H, H1e1
0
0
4.3. Synthesis of porphyrins
s, 4H, H
0e900).
9
4.3.1. Synthesis of porphyrin 6. Tetrakis(3,5-dimethoxyphenyl)
4
.2.4. Synthesis of new tetrapod dendron 11. The brominated com-
porphyrin (OOMePP) was prepared from pyrrole and the respective
aromatic aldehyde using AdlereLongo condensation conditions.
2
4
pound 10 (175 mg, 0.31 mmol) was placed in a three-necked flask
under an argon atmosphere and then dissolved in distilled THF
(
20 mL). The commercial alcohol, 5-hydroxymethyl-benzen-1,3-
4.3.2. Synthesis of porphyrin 7. Tetrakis(3,5-dihydroxyphenyl)por-
phyrin (OOHPP) was prepared by boron tribromide deprotection of
tetrakis(3,5-dimethoxyphenyl)porphyrin 6.
diol (21 mg, 0.15 mmol) was added and then potassium carbon-
ate (83 mg, 0.60 mmol) and finally 18-crown-6 ether (40 mg,
0
.15 mmol). The three-necked flask was surmounted by a water
condenser and the solution was heated to reflux for 15 h. The so-
lution was left until cooled to room temperature and then filtered
over a frit funnel. The filtrate was evaporated and the residue was
dissolved in DCM and transferred into a separating funnel. The
organic layer was washed two times with distilled water and one
time with a saturated solution of sodium chloride. Aqueous layers
were combined and extracted one time with DCM. Organic layers
4.3.3. Synthesis
hydroxyphenyl)porphyrin (TOFP) was described earlier. H NMR
3
(300 MHz, solubilized by acidic deuterated TFA in CDCl , d in ppm):
of
porphyrin
2. Tetrakis(fluorenyl-4-
18 1
3
3
8.54 (d, JHH¼8.4 Hz, 8H, H
B
), 8.52 (s, 8H, pyrrole), 7.96 (d, JHH¼7
), 7.87 (s, 4H, H ), 7.68 (d,
HH¼8.4 Hz, 8H, H ), 7.64 (d,
), 7.38 (t,
3
.8 Hz, 4H, H
4
0
), 7.90 (d, JHH¼7.4 Hz, 4H, H
5
0
0
1
3
3
JHH¼7.8 Hz, 4H, H
J
J
3
0
), 7.65 (d,
), 7.46 (t,
J
J
D
3
3
3
HH¼7.3 Hz, 4H, H
8
0
HH¼7.6 Hz, 4H, H
6
0
4
were combined and dried over MgSO , filtered and the solvent was
HH¼7.4 Hz, 4H, H
7
0
), 5.52 (s, 8H, HHeH
0
), 4.06 (s, 8H, H
9
0e900).
evaporated. The oil obtained was subjected to column chroma-
tography of silica with DCM as eluent. The expected compound 11
was obtained as a thin white powder (115 mg, 70%). H NMR
4.3.4. Synthesis of octafluorenylporphyrin OOFP (3). Synthesis of
1
18 1
octafluorenylporphyrin OOFP (3) was described earlier.
H NMR
3
(
300 MHz, CDCl
3
,
d
in ppm): 7.78, (d, 4H, H
4
0
0
,
J
HH¼7.5 Hz), 7.77
(300 MHz, CDCl in ppm): 8.83 (s, 8H, pyrrole), 7.81 (d,
3
, d
3
3
3
(
d, 4H, H
5
0
,
J
HH¼7.5 Hz), 7.61 (s, 4H, H
1
), 7.55 (d, 4H, H
HH¼7.6 Hz), 7.39 (t, 4H, H
8
6
B
0
0
0
,
,
,
,
,
J
HH¼7.9 Hz, 8H, H
4
0
), 7.80 (d, JHH¼7.6 Hz, 8H, H
), 7.54 (s, 8H, H
), 7.52 (d, JHH¼8.0 Hz,
), 7.32 (t, JHH¼7.2 Hz, 8H, H
), 5.33 (s, 16H, HHeH ), 3.91 (s, 16H,
5
0
), 7.72 (s, 8H, H
1
0
),
3
3
3
3
3
3
J
J
J
HH¼7.2 Hz), 7.41 (d, 4H, H
3
0
,
J
7.55 (d, JHH¼7.4 Hz, 8H, H
8
0
B
3
3
3
HH¼7.6 Hz), 7.32 (t, 4H, H
7
0
,
J
HH¼7.2 Hz), 6.73 (d, 4H, H
8H, H
7.18 (t,
H
9
0e900).
3
0
), 7.40 (t, JHH¼7.2 Hz, 8H, H
6
0
0
7
),
3JHH¼2.3 Hz), 6.59 (d, 2H, H
3
3
J
HH¼2.2 Hz, 4H, H
HH¼2.1 Hz), 6.65 (t, 2H, H
E
0
,
B
00
E
0
3JHH¼2.1 Hz), 6.55 (t, 1H, H
,
J
HH¼2.3 Hz), 5.12 (s, 8H, OCH
00
E
2
2
H
H
H2eH2
H11eH11
60
0
), 5.00 (s, 4H, OCH
0
, HH1eH1
0
), 4.59 (d, 2H, CH
2
eOH,
e900). Anal. Calcd
3
, JHH¼5.7 Hz), 3.90 (s, 8H, CH2fluorene, H
9
0
4.3.5. Synthesis of sixteenfluorenylporphyrin SOFP (4). Synthesis of
19 1
for C77
5
H
O
7
$1CH
2
Cl
2
: C, 79.24; H, 5.29; N, 0.00. Found: C, 80.29; H,
sixteenfluorenylporphyrin SOFP (4) was described earlier.
H
þ
.56; N, 0.00. MALDI TOF-MS calcd for C77
60
H O
7
ꢂ
: 1119.4339 [MNa] ,
found 1119.1800 [MNa] . Melting point: 130.1 C.
NMR (300 MHz, CDCl in ppm): 8.85 (s, 8H, pyrrole), 7.55 (d,
3
, d
), 7.49 (d,
), 7.35 (s, 16H, H
þ
3
3
J
HH¼7.4 Hz, 16H, H
5
0
J
HH¼7.8 Hz, 16H, H
4
0
), 7.45 (d,
4
3
JHH¼2.2 Hz, 8H, H
B
1
0
), 7.34 (d,
J
HH¼7.4 Hz, 16H,
3
3
4.2.5. Synthesis of new tetrapod dendron 12. Alcohol 11 (75 mg,
H
8
0
), 7.22 (t,
J
HH¼6.7 Hz, 16H, H
6
0
), 7.16 (t,
J
HH¼7.3 Hz, 16H, H
), 7.04 (t, JHH¼2.1 Hz, 4H, H ), 6.70 (d,
), 5.07 (s, 16H,
e900), ꢀ2.72 (br s,
160.30 (C ), 157.91
00), 143.00 (broad signal
00), 141.19 (C 00), 135.13 (C
), 131.00
(broad signal C2e3e7e8e12e13e17e18), 126.68 (C ), 126.65 (C
126.28 (C ), 124.94 (C ), 124.26 (C ), 119.86 (C ), 119.76 (C
115.36 (C ), 106.45 (C ), 102.42 (C
(C ), 70.38 (CH1), 70.31 (CH2), 36.67 (C
7
0
),
3
4
0
.07 mmol) was placed in a Schlenk tube under an argon atmo-
7.15 (d, JHH¼7.1 Hz, 16H, H
3
0
E
4
4
sphere and then dissolved in distilled THF (1.5 mL). Carbon tet-
rabromide (37 mg, 0.11 mmol) was added and the reaction
JHH¼2.1 Hz, 16H, H
B
0
), 6.59 (t,
J
HH¼2.1 Hz, 8H, H
), 3.66 (s, 32H, H
in ppm):
0
E
H
H1eH1
0
), 4.92 (s, 32H, HH2eH2
0
0
9
ꢂ
13
mixture was cooled to 0 C with an ice bath, followed by the
2H, NH). C NMR (300 MHz, CDCl
(C ), 143.54 (C
00), 143.32 (C
1e4e6e9e11e14e16e19), 141.50 (C
3
,
d
d
0
D
portion-wise addition of triphenylphosphine (29 mg, 0.11 mmol).
D
9
4
ꢂ
The reaction mixture was stirred at 0 C for 1 h. The ice bath was
C
8
5
0
2
removed and the reaction mixture was stirred at room temper-
ature for 3 h. Repetitive additions of 4 equiv of carbon tetra-
bromide, 1.5 mL of THF followed by addition of 4 equiv of
triphenylphosphine were done twice every 12 h. Reaction prog-
ress is monitored by TLC, spotting directly from the organic layer.
The solution was transferred in a separating funnel with distilled
water. The aqueous layer was extracted three times with DCM.
7
0
6
4
0
0
),
),
0
0
0
0
5
3
8
1
0
), 102.41 (C5e10e15e20), 101.86
).
B
B
E
0
0
9
E
4.3.6. Attempt to synthesis porphyrin 32Fdformation of compound
1. The tetrakis (3,5-dihydroxyphenyl)-porphyrin (3.6 mg,
7
ꢀ
6
Organic layers were combined and dried over MgSO
4
and then
4.8ꢁ10 mol) was placed in a Schlenk tube, under an argon at-
mosphere and then dissolved in distilled THF (3 mL). Potassium
carbonate (11 mg, 7.7ꢁ10ꢀ mol), 18-crown-6 ether (1.3 mg,
the solvent was evaporated. The light brownish oil obtained was
subjected to column chromatography over silica with DCM as
5

7910
A. Merhi et al. / Tetrahedron 68 (2012) 7901e7910
ꢀ
6
þ
þ
þ
4
.8ꢁ10 mol) were added to this solution, and finally, the bromide
1101.41311 [MNa] , 1117.38705 [MK] ; found: 1101.41150 [MNa] ,
ꢀ
5
þ
dendron 12 (50 mg, 4.3ꢁ10 mol) was added. Then, the solution
1117.37140 [MK] .
was stirred under argon and heated to reflux for 2 days. Repetitive
ꢀ5
additions of 16 equiv of K
2
CO
3
(11 mg, 7.7ꢁ10
6
mol) and 18-
Acknowledgements
ꢀ
crown-6 ether (1.3 mg, 4.8ꢁ10 mol) were done every 2 days.
Reaction progress is monitored by TLC, spotting directly from the
organic layer. Then, at the end of the reaction (eight days), the
mixture was cooled to room temperature and THF was evaporated
in vacuum. The residue was dissolved in DCM and transferred into
a separating funnel. The organic layer was washed two times with
distilled water and one time with a saturated solution of sodium
chloride. Aqueous layers were combined and extracted one time
with DCM. Organic layers were combined. The organic layer
The authors are grateful to S. Sinbandhit (CRMPO-Rennes), G.
Simonneaux and P. Le Maux (ICMV-ISCR-UMR 6226) for their
technical assistance and helpful discussions. The authors are
grateful to MRT for Ph.D. grant concerning S.D. and Region Bretagne
for ARED grant for A.M.. Partial funding for the project was obtained
from the ‘Universit eꢀ Europ eꢀ enne de Bretagne’ (UEB) and from
FEDER by an EPT grant in the ‘MITTSI’ program from RTR BRESMAT.
4
obtained was dried over MgSO , filtered and the solvent was
References and notes
evaporated. The brown product obtained was subjected to column
chromatography over silica with 100% DCM as eluent and then
a mixture of DCM/acetone gradient and finally, 100% acetone. Two
products were obtained: compound 1 as a pale yellow product
1. Abraham, R. J.; Hawkes, G. E.; Hudson, M. F.; Smith, K. M. J. Chem. Soc., Perkin
Trans. 2 1975, 204e211.
2. Fonda, H. N.; Gilbert, J. V.; Cormier, R. A.; Sprague, J. R.; Kamioka, K.; Connolly, J.
S. J. Phys. Chem. 1993, 97, 7024e7033.
3. Toeibs, A.; Haeberle, N. Justus Liebigs Ann. Chem. 1968, 718, 183e187.
4. Li, B.; Xu, X.; Sun, M.; Fu, Y.; Yu, G.; Liu, Y.; Bo, Z. Macromolecules 2006, 39,
(
24 mg, yield: 52%) and a dark red product; a mixture of differently
substituted porphyrins (12 mg, yield around 40%). Separation of
these porphyrins was unsuccessfully tried but compound 1 was
isolated pure. This new compound 1 was characterized by NMR,
456e461.
5
. Li, B.; Li, J.; Fu, Y.; Bo, Z. J. Am. Chem. Soc. 2004, 126, 3430e3431.
6. Harth, E. M.; Hecht, S.; Helms, B.; Malmstrom, E. E.; Fr eꢀ chet, J. M.; Hawker, C. J. J.
1
microanalysis and mass spectrometry. H NMR (assignments aided
Am. Chem. Soc. 2002, 124, 3926e3938.
7. Dichtel, W. R.; Serin, J. M.; Edder, C.; Fr eꢀ chet, J. M. J. Am. Chem. Soc. 2004, 126,
3
by COSY; 300 MHz, CDCl
3
,
d
in ppm): 7.80 (d, 3H, H
4
0
, JHH¼¼.3 Hz),
5380e5381.
3
7
H
H
.78 (d, 3H, H
5
0
, JHH¼7.3 Hz), 7.72-7.62 (m, 3H, H5e6ꢀ8), 7.59 (d, 3H,
ꢀ
8. Oar, M. A.; Serin, J. M.; Frechet, J. M. Chem. Mater. 2006, 18, 3682e3692.
3
3
0
, JHH¼5.1 Hz), 7.56 (d, 3H, H
0
, JHH¼5.1 Hz), 7.43e7.37 (m, 6H,
9. Sun, M.; Bo, Z. J. Polym. Sci., Part A: Polym. Chem. 2006, 45, 111e124.
10. Paul-Roth, C.; Rault-Berthelot, J.; Simonneaux, G. Tetrahedron 2004, 60,
8
3
3
0
0
), 7.44e7.36 (m, 3H, H3e4e7), 7.33 (t, 3H, H
0
, JHH¼7.0 Hz), 6.78
1
e6
7
12169e12175.
3
3
(
d, JHH¼2.2 Hz, 2H, 2H
B
0
), 6.75 (m,1H, H
B
00), 6.65 (t, JHH¼2.2 Hz,1H,
00), 6.54 (m, 1H, H
), 6.48 (t,
), 6.39 (m, 1H,
11. Poriel, C.; Ferrand, Y.; Le Maux, P.; Paul-Roth, C.; Simonneaux, G.; Rault-Berthelot,
H
E
0
), 6.61 (t, 3
J
HH¼2.2 Hz, 1H, H
E
E
J. J. Electroanal. Chem. 2005, 583, 92e103.
12. Paul-Roth, C. O.; Simonneaux, G. Tetrahedron Lett. 2006, 47, 3275e3278.
13. Paul-Roth, C. O.; Simonneaux, G. C.R. Acad. Sci., Ser. IIb: Chim. 2006, 9,
3
3
J
HH¼2.2 Hz, 1H, H
B
), 6.44 (t,
J
HH¼2.2 Hz, 1H, H
9
2
H
Bcycle), 6.02 (m, 1H, H
B
00cycle), 5.14 (d, 1H, H
F
, JHH¼13.1 Hz), 5.12 (s,
1
277e1286.
14. Paul-Roth, C.; Williams, G.; Letessier, J.; Simonneaux, G. Tetrahedron Lett. 2007,
8, 4317e4322.
15. Drouet, S.; Paul-Roth, C. O.; Fattori, V.; Cocchi, M.; Williams, J. A. G. New J. Chem.
011, 35, 438e444.
16. Ren, X.;Ren, A.; Feng, J.;Sun, C. J. Photochem. Photobiol., A: Chem. 2009, 203, 92e99.
7. Drouet, S.; Merhi, A.; Argouarch, G.; Paul, F.; Mongin, O.; Blanchard-Desce, M.;
Paul-Roth, C. O. Tetrahedron 2012, 68, 98e105.
6
J
H, OCH
2
, HH2eH2
0
), 5.05 (s, 4H, OCH
2
, HH1eH1
0
), 4.91 (d, 1H, H
G
,
2
2
3
4
HH¼13.1 Hz), 4.08 (dd, 1H, HH11, JHH¼11.09 Hz, JHH¼4.1 Hz), 3.89
2
(
s, 6H, 3CH2fluorene, H
J
9
0
e900), 3.59 (dd, 1H, H H11
0
(cycle),
J
HH¼13.0 Hz,
2
3
2
3
13
HH¼4.7 Hz), 2.21 (dd, 1H, Hx,
assignments aided by COSY; 300 MHz, CDCl
60.0 (C ), 159.4 (C
00), 159.8 (C
00), 143.7, 143.6, 143.4, 142.2, 141.7, 141.6, 141.3 (C
40.3, 139.8, 139.4 (C ), 135.3, 135.2, 134.7, 127.8 (C
27.4e127.3e127.1 (C5e6e8), 126.8 (C ), 126.7 (C ), 126.4 (C
), 124.1 (C3e4e7), 120.1, 120.0, 119.9, 119.8 (C
00cycle), 106.5, 105.45, 104.7, 103.9, 102.1 (C
), 70.50, 70.33, 70.1, 69.9, 69.1, 49.3 (C ), 40.8 (CH11eH11
$Na: C, 83.90; H, 5.30; N,
.00. Found: C, 83.91; H, 6.02; N, 0.00. MS (ESI): calcd for C77
J
HH¼13.1 Hz, JHH¼11.4 Hz). C NMR
1
(
3
,
d
in ppm): 160.3 (C
), 147.3 (C ), 145.3
), 140.7 (C
q
),
1
D
q
D
00cycle), 158.9 (C
q
q
1
8. Drouet, S.; Paul-Roth, C.; Simonneaux, G. Tetrahedron 2009, 65, 2975e2981.
19. Drouet, S.; Paul-Roth, C. O. Tetrahedron 2009, 65, 10693e10700.
20. Fr
(
C
A
q
2
1
),
),
eꢀ chet, J. M. J.; Tomalia, D. A. In Dendrimers and Other Dendritic Polymers; John
1
q
Wiley & Sons: Chichester, UK, 2001.
1
3
0
4
0
8
0
), 125.0
), 108.9
00), 101.6
), 36.8,
21. Jiang, D.-L.; Aida, T. J. Am. Chem. Soc. 1998, 120, 10895e10901.
(C
(C
(C
7
0
), 124.4 (C
00), 108.6 (C
5
0
q
2
2
2
2. Nicholson, J. W. The Chemistry of Polymers; Royal Society of Chemistry: Great
Britain, 2006.
B
B
E
3. V o€ gtle, F.; Richardt, G.; Werner, N. Dendrimer Chemistry: Concepts, Syntheses,
0
t
9
Properties, ApplicationsdScience; Wiley: Weinheim, 2009.
4. Kim, J. B.; Adler, A. D.; Longo, F. R. In The Porphyrins; Dolphin, D., Ed.; Academic:
New York, NY, 1978; Vol. 1; Part A, p 85.
2
58 6
9.7, 29.3, 22.7. Anal. Calcd for C77H O
0
H
58
O
6
: