Photoinduced energy and electron transfer in 1,8-naphthalimide-corrole dyads

Article abstract of DOI:10.1039/b613640k

A series of corrole-1,8-naphthalimide dyads has been synthesized. The dyads were assembled in a convergent fashion from two fragments via a corrole forming reaction. Central to the success of the synthetic strategy was the preparation of suitably functionalized derivatives of naphthalene-1,8-carboxymide. Six different dyads possessing either a different linker (a meta-phenylene or a para-phenylmethylene) or a corrole with different substituents at the 5 and 15 positions were prepared. A photophysical and spectroscopic characterization of the dyads and the reference models show that whereas upon selective excitation of the corrole component no photo-induced process occurs, excitation of the naphthalimide unit results in very efficient energy or electron transfer processes. The electron transfer contributes to the quenching process with a ratio between 0% and 85% depending on the nature of the corrole accepting unit. The processes are discussed in the frame of current theories. This is the first report of stable corrole-based dyads with interesting photo-activity at ambient temperature. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

Full text of DOI:10.1039/b613640k

View Article Online / Journal Homepage / Table of Contents for this issue
PAPER
www.rsc.org/njc | New Journal of Chemistry
Photoinduced energy and electron transfer in 1,8-naphthalimide–corrole
dyads
Mariusz Tasior,a Daniel T. Gryko,*a Marek Cembor,b Jan S. Jaworski,b
Barbara Venturac and Lucia Flamigni*c
Received (in Durham, UK) 19th September 2006, Accepted 30th November 2006
First published as an Advance Article on the web 20th December 2006
DOI: 10.1039/b613640k
A series of corrole-1,8-naphthalimide dyads has been synthesized. The dyads were assembled in a
convergent fashion from two fragments via a corrole forming reaction. Central to the success of
the synthetic strategy was the preparation of suitably functionalized derivatives of naphthalene-
1,8-carboxymide. Six different dyads possessing either a different linker (a meta-phenylene or a
para-phenylmethylene) or a corrole with different substituents at the 5 and 15 positions were
prepared. A photophysical and spectroscopic characterization of the dyads and the reference
models show that whereas upon selective excitation of the corrole component no photo-induced
process occurs, excitation of the naphthalimide unit results in very efficient energy or electron
transfer processes. The electron transfer contributes to the quenching process with a ratio between
0% and 85% depending on the nature of the corrole accepting unit. The processes are discussed
in the frame of current theories. This is the first report of stable corrole-based dyads with
interesting photo-activity at ambient temperature.
since they became easily available after the last develop-
ments.11 Their availability has been steadily increasing since
Introduction
1999 to challenge the supreme position of porphyrins.12 Sur-
Photoinduced electron and energy transfer play a key role in
light-driven chemical, physical and biological processes.
prisingly, fundamental photophysical behavior of corroles has
been rarely studied until recently.13,14 These aromatic tetra-
Photosynthesis represents a noteworthy and ubiquitous model
that has motivated design of many elaborate assemblies to
pyrrolic macrocycles exhibit some interesting properties when
convert light energy into chemical potential.1 Although re-
compared to porphyrins: higher fluorescence quantum yield,
search done in this area has explained many phenomena and
larger Stokes shift, no phosphorescence, more intense absorp-
answered many questions, unsolved problems provide ratio-
tion of red light. Moreover, corroles combine in the same
nale to search for new systems differing from the previous ones
molecule a reasonable ease of oxidation with a reasonable ease
for photoactive unit, linker, spatial arrangement, etc.2 In order
of reduction. Stable systems containing corrole linked with
to mimic the photosynthetic processes, covalently linked arrays
of various chromophores and various complexity are used.1
transfer under normal conditions have been unknown until
other chromophores able to exhibit electron transfer or energy
now.14e,f Studying corroles offers some additional interesting
Although a great variety of organic and inorganic photoactive
unit have been investigated, in this regard porphyrins are still
challenges and opportunities. Attaching corroles to electron
the most often used.3 Porphyrins almost monopolize the study
acceptors should lead to more stable molecules since the
of photoactive arrays, due to their easy availability and large
effective electron density on corrole will decrease after excita-
body of information on their synthetic manipulations4 and
tion and electron transfer. Recently, we started a broad
photophysical processes.5 However many other porphyrinoids
photophysical project aiming to explore the possibilities of-
fered by corroles as part of multicomponent systems.13 Among
have interesting photophysical properties and have been used
as photoactive components in the construction of models
many different counterpart chromophores we decided to focus
mimicking various stages of photosynthesis. For example
on aromatic imides which can act both as electron acceptor
phthalocyanins,6 subphthalocyanins,7 chlorins,8,9 or fused por-
and as energy donor. A variety of porphyrin–aromatic imides-
phyrins,10 have been successfully used for making photo-active
based multicomponent systems bearing four or more donor
and acceptor moieties have been reported.1d,e,3e,15 Aromatic
multipartite arrays. Between others corroles—one carbon
short analogs of porphyrins-have one additional advantage,
imides have proven useful in dyads and more complex devices;
they are chemically very robust and can be linked to other
a Institute of Organic Chemistry of the Polish Academy of Sciences,
Kasprzaka 44/52, 01-224 Warsaw, Poland. E-mail:
molecules in ways that limit conformational mobility. We have
chosen 1,8-napthalimides as the simplest, prototypical example
of the aromatic imides family. Derivatives of 1,8-naphthal-
imide have been extensively studied in recent years owing to
their interesting photophysical properties16 and the wide range
of applications.17
daniel@icho.edu.pl; Fax: +48 22 6326681; Tel: +48 22 3432036
b Faculty of Chemistry, Warsaw University, Pasteura 1, 02-093
Warsaw, Poland
c ISOF-CNR, Via P. Gobetti 101, 40129 Bologna, Italy. E-mail:
flamigni@isof.cnr.it; Fax: 39 051 6399844; Tel: 39 051 6399812
ꢀc
This journal is the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2007
New J. Chem., 2007, 31, 247–259 | 247

View Article Online
They are known to act as electron acceptor,18a,b electron
donor18c or energy donor18d in various systems ranging from
1,8-napthalimide core, endowed with an aldehyde functional-
ity for further elaboration. Obviously, synthons for such
synthesis had to possess both primary amino and formyl
groups, but the latter one has to be present in a protected
form. We started our experiments with attempts to synthesize
an aldehyde bearing the para-phenylene linker. Initially, we
thought that the simplest way to prepare the corresponding
aldehyde would be starting from anhydride 1 and para-
toluidine 2. In analogy to previous results with N-phthaloyl-
para-toluidine13b we planned to oxidize methyl group to
formyl group in respective imide 5. This compound was
synthesized from anhydride 1 according to a known proce-
dure, however all attempts to oxidize it to the corresponding
aldehyde 6 failed regardless of the use of numerous reagents
like CAN, IBX, PCC, SeO2 etc. (Scheme 1).
sensitizers for Gratzel-type solar cells19a,b to logic gates,19c
¨
sensors19d and charge separation mimics.18c An advantage of
1,8-napthalimides over analogous pyromelitic bisimide,
napthalbisimide and perylenebisimide is the simple prepara-
tion of the necessary intermediates and the reasonable solubi-
lity. In principle 1,8-napthalimides can absorb blue, green, or
yellow light by adjusting the substituent at its 4-position.20 We
have chosen unsubstituted 1,8-napthalimides which absorb
high-energy photons (lmax = 335 nm) which could be trans-
mitted to the corrole core via possible energy transfer.
In this paper we chose three different corroles to couple to
the 1,8-napthalimide and varied the oxidation potential of the
former by using different substitution patterns. At the same
time we changed the linker between the imide component,
which plays the role of electron acceptor and energy donor,
and the corrole component, acting as electron donor and
energy acceptor, in order to change the electronic coupling
between the units. Our aim is to exploit the ability of the dyads
to act as energy or electron transducer. The results indicate
that the energy stored in the excited state of the imide can be
efficiently used either to transfer electrons from the corrole to
the imide or to transfer energy from the imide to the corrole,
and that the relative yield of the processes is tuned by the
redox properties of the corrole.
Another option which was considered, started from the
respective 4-aminobenzyl alcohol 3. The corresponding imide
would be then an excellent precursor of the aldehyde 6.
Unfortunately, the exposure of alcohol 3 to anhydride 1 in
boiling DMF resulted in an intractable mixture which did not
contain even traces of the desired product (Scheme 1). The
failure in this reaction can be attributed to competitive decom-
position of substrate under the reaction conditions. All at-
tempts to perform this process under more gentle conditions
failed (Scheme 1).
It is known that commercially available polymer of 4-
aminobenzaldehyde 4 reacts with phthalic anhydride to give
the respective 4-(N-pthaloyl)benzaldehyde in a good yield.22
The reaction of the polymer of 4-aminobenzaldehyde with
anhydride 1 in boiling acetic acid failed to give the desired
aldehyde in reasonable yield (Scheme 1).
Results and discussion
Design
Several issues merit particular consideration when contemplat-
ing the synthesis of complex corrole containing dyads. From
the standpoint of synthetic efficiency, in analogy to porphyr-
ins, two general strategies are possible. The first one starts with
the synthesis of corrole followed by modifications of periph-
eral substituents. The second strategy would start with the
preparation of an elaborated aldehyde which would then be
used in the corrole forming reaction. Given the moderate
stability of corroles it is desirable to gain significant relief
from the corrole manipulations. In this regard we decided to
follow the second route.
In the light of these results and due to the fact that the exact
structure of the connector was not a crucial objective in this
project we turned our attention to an alternative meta-pheny-
lene linker. The reaction of 3-aminobenzyl alcohol 7 with
anhydride 1 furnished the respective imide 9 in 55% yield.
Subsequently, alcohol 9 was oxidized to aldehyde 10 using
Dess–Martin periodinate in quantitative yield (Scheme 2). We
found that aldehyde 10 can be also obtained directly from
polymer of 3-aminobenzaldehyde 8 and anhydride 1 in boiling
acetic acid in 90% yield (Scheme 2).
The second important building block—aldehyde 13—was
synthesized from aminoacetal 11 obtained from 4-cyanoben-
zaldehyde according to literature procedure.23 This compound
We decided to build up on our experience in the synthesis
of meso-substituted trans-A2B-corroles from dipyrromethanes
and aldehydes.21 This methodology allows to introduce the
desired substituent at the 10 position of the macrocycle
core. The two remaining identical substituents at the positions
5 and 15 allow the control of other properties of the system
like: solubility, stability and redox properties. We envisaged
using a few different type of substituents at these positions.
As far as the linker connecting both chromophores is con-
cerned we have chosen simple phenylene and phenylmethylene
groups which should guarantee a good structural control
and a sufficient electronic coupling to allow intramolecular
processes.
Synthesis
In the light of the above considerations the crucial part of
the dyads’ synthesis was the facile generation of the pivotal
Scheme 1
ꢀc
This journal is the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2007
248 | New J. Chem., 2007, 31, 247–259

View Article Online
and allows an approach based on a localized description of the
individual subunits.
From inspection of the spectra of Fig. 1 one can see that
selective excitation of the corrole component in the dyads is
possible at wavelength 4380 nm, whereas excitation of the
imide unit is possible only with a ca. 50% ratio (i.e. 50%
excitation of corrole component and 50% excitation of the
imide component) in the range 330–350 nm.
The luminescence spectra of imides NI1 and NI2 in toluene
upon excitation at 330 nm are shown in Fig. 2 upper panel,
both at 295 K and at 77 K in a rigid toluene matrix. There is a
Scheme 2
very low room temperature luminescence from NI1, Ffl
=
7 ꢂ 10ꢁ5, and a good luminescence from NI2, Ffl = 0.015,
lmax at 396 nm, whereas at 77 K intense fluorescence and a
weak phosphorescence are detected from both imides.
The luminescence spectra of corrole models in toluene upon
excitation at 560 nm are reported in the lower panel of Fig. 2.
Their emission yields is variable, Ffl = 0.22 for C1, Ffl = 0.06
for C2 and F = 0.14 for C3, but within values typical for free-
base corroles.13a,14b,d As observed previously no phosphores-
cence is observed in any of the examined corroles.13a
was found to react with anhydride 1 in boiling EtOH in 100%
yield. Subsequent cleavage of the acetal group with a mixture
of TFA and H2SO4 furnished aldehyde 13 in 95% yield
(Scheme 3).
The next stage of our synthesis involved the construction of
the corrole ring via a [2 + 1] route. This strategy was
extensively studied and corroles were prepared from aldehydes
10 and 13 under conditions previously optimized.21 In order to
diversify oxidation potential we decided to use three different
dipyrromethanes 14, 15 and 16. Among them mesityldipyrro-
methane 14 is precursor of corroles that is rather easy to
oxidize. On the other hand the presence of pentafluorophenyl
groups (dipyrromethane 16) is known to increase significantly
the oxidation potential of corroles.24 Dyads C1-NI1, C1-NI2,
C1-NI3, C2-NI1, C2-NI2 and C2-NI3 were synthesized with
yields in the range 6–22% (Scheme 4, Chart 1). Exceptionally
low yield was obtained for dyad C1-NI1. This result was
attributed to low stability of this corrole and to its partial
decomposition during purification process. Additional five
model compounds, C1, C2, C3, NI1 and NI2 (Chart 1), needed
for our study were synthesized in analogous way from
dipyrromethanes 14, 15, 16 and para-tolualdehyde or from
anhydride 1 and simple primary amines.
Spectroscopic and photophysical properties
A spectroscopic and photophysical investigation was carried
out on corrole component models C1, C2, C3 and on naphtha-
lene imide component models NI1 and NI2 as well as on the
six dyads C1-NI1, C2-NI1, C3-NI1 and C1-NI2, C2-NI2, C3-
NI2 reported in Chart 1. The absorption spectrum of imides
NI1 and NI2 in toluene is nearly identical and displays bands
at 333–334 nm (e = 12 800 Mꢁ1 cmꢁ1) and 347–349 nm (e ca.
11 400 Mꢁ1 cmꢁ1), Table 1. Model C1 displays a splitting of
the Soret band which is typical of corroles with meso aryl
groups bearing a bulky ortho substituent13a and previously
assigned to a deviation from planarity of the macrocycle
induced by crowding of substituents.14b Also the chlorine
substituted corrole model C2 displays such splitting which is
absent in the case of fluorine substituted corrole C3 (Table 1
and Fig. 1).
The dyads C1-NI1, C2-NI1, C3-NI1 and C1-NI2, C2-NI2,
C3-NI2 display spectra which are essentially the superimposi-
tion of the absorption spectra of the component models, Table
1 and Fig. 1. The good additive properties of the spectra points
to a rather weak electronic coupling between the components
Scheme 3
ꢀc
This journal is the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2007
New J. Chem., 2007, 31, 247–259 | 249

View Article Online
corrole at 560 nm in the dyads yields emission spectra iden-
tical, within experimental error, to those of optically matched
solutions of the corresponding corrole, showing that in the
dyads no quenching occurs upon excitation of the corroles
(Table 2). The results upon excitation of the dyads at 350 nm
compared with the models absorbing the same number of
photons in the dyads are shown in Fig. 3. In all cases the
luminescence localized on the imide NI2 and NI1 is totally
quenched in the dyads. The quenching of the imide moiety is
followed by a poor sensitization of the corrole unit in C1-NI1
and C1-NI2 (Fig. 3, upper panel), a significant sensitization of
the corrole unit is registered in C2-NI1 and C2-NI2 (Fig. 3,
middle panel) and a quantitative sensitization is detected in
C3-NI1 and C3-NI2 (Fig. 3, lower panel), respectively. The
data are collected in Table 2. The complete quenching of imide
units in the dyads occurs also at 77 K in a toluene glass, data
not shown, it is however difficult due to the experimental
conditions (see experimental section) to quantitatively assess
the sensitization of the corrole unit.
Time resolved luminescence studies with picosecond resolu-
tion and 355 nm excitation indicate a lifetime shorter than the
instrumental resolution (10 ps) for imide units in the dyads
and this points to the occurrence of an efficient quenching of
this unit in the array. The quenching rate can be determined
from the equation k = 1/t ꢁ 1/t0, where t and t0 are the
lifetimes of the quenched unit (i.e. in the dyad) and the lifetime
of the unquenched unit (i.e. in the model), respectively, and
results to be k 4 1011 ꢁ1. On the contrary the lifetime of
s
corrole in the dyads excited both at 355 nm and at 532 nm is
essentially identical to that of the model, see Table 2.
Scheme 4
Photoinduced processes
In order to discuss the photoinduced processes occurring in
the dyads it is convenient to introduce the energy level diagram
reporting the energy of the excited states and of the states
originating from possible intramolecular reactions, i.e. the
charge separated (CS) states derived from the transfer of an
electron from one component to the other (Fig. 4). The excited
state energy levels are derived from the luminescence maxima
at 77 K of Table 2. As far as the CS state energy levels are
concerned, these can be derived from the energy necessary to
reduce the acceptor and to oxidize the donor, i.e. from the
redox potentials. Both NI1 and NI2 are reversibly reduced in
benzonitrile at ꢁ1.20 V vs. SCE by a one-electron process, in
line with the literature data on similar aromatic imides and
bisimides.26–30 In the arrays the value was only slightly shifted
to more negative values and almost independent of the corrole:
ꢁ1.23 V for C1-N1, C1-N2, C2-NI1 and C2-NI2 and ꢁ1.22 V
and ꢁ1.20 V for C3-NI1 and C3-NI2, respectively. Corroles
are known to display an irreversible oxidation at potentials
which depends on the substitution pattern.24 The one electron
oxidation is followed by fast chemical reactions24 which shift
peak potentials to less positive values. Thus, oxidation peak
potentials found should be considered as lower limits of the
thermodynamic oxidation potentials. That approximation
should be remembered in the following estimation of CS state
levels. Oxidation of the present corroles in benzonitrile occurs
at 0.58 V for C1, at 0.72 V for C2, and at 0.86 V for C324; these
Time resolved experiments in the pico and nanosecond
range in air-equilibrated toluene allow to derive lifetimes of
10 ps for NI1, 245 ps for NI2 and 5.1 ns, 1.7 ns, 3.8 ns for C1,
C2 and C3, respectively (Table 2). The anomalous behavior of
1,8-naphthalene imide NI1 with respect to NI2 and other
naphthalene imides,16a consisting of an extremely short life-
time and a very weak room temperature luminescence seems to
be related to the phenyl substituent at the nitrogen. Similar
results were in fact detected from an N-phenyl 2,3-naphthalene
imide (Ffl o 2 ꢂ 10ꢁ4, t o 50 ps) and assigned to the
formation, in addition to the normal twisted singlet excited
state, of a singlet excited state exhibiting co-planarity of the
naphthalene and phenyl rings. This state, weakly emitting
around 500 nm, is characterized by some charge transfer
character and deactivates through rotational or torsional
motion of the phenyl substituent.25 In the present case we do
not detect any weak emission around 500 nm, but the inter-
pretation given for the poor luminescence from N-phenyl 2,3-
naphthalene imide can also satisfactorily explain the very low
luminescence yield and lifetime of the present NI1 chromo-
phore.
The steady state luminescence properties of the dyads were
probed upon excitation at 560 nm, where only corrole absorbs
and upon excitation at 350 nm, where both imide and corrole
moieties absorb 50% of the light. Selective excitation of
ꢀc
This journal is the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2007
250 | New J. Chem., 2007, 31, 247–259

View Article Online
Chart 1 Structures of studied compounds.
data are either unaltered or shifted to slightly more positive
values in the array: 0.59 V for C1-N1 and C1-N2, 0.76 V and
0.75 for C2-NI1 and C2-NI2 and 0.85 V and 0.84 V for C3-NI1
and C3-NI2, respectively. The small change in the redox
processes localized on the units of the arrays compared to
the simple models indicate a modest electronic coupling
between components of the dyad. The CS state levels in
toluene can be estimated after correction for the different
solvent used in electrochemistry (benzonitrile). The common
correction used to determine the CS state energy level in an
apolar solvent from the values of the first oxidation potential
of the donor Eox and the first reduction potential of the
acceptor Ered in a polar solvent takes into account the
Coulombic interaction term and the ion solvation energy
based on the Born dielectric continuum model according to
Weller.31 This correction tends to overestimate the energy of
the charge separated state in those cases when an excited state
with charge transfer character is involved in the formation of
the CS state, therefore we should have in mind that the derived
values can be approximate.32 The energy of the charge sepa-
rated states relative to the ground state, DGCS, can thus be
calculated by the following equation31:
DGCS = Eox ꢁ Eredꢁ(14.32 /RDAeS) + 14.32
(1/2rD + 1/2rA) (1/eS ꢁ 1/eP)
(1)
For the formation of the generic charge separated state
C+–NIꢁ, involving the transfer of an electron from the corrole
to the imide, Eox and Ered are the first oxidation potential of
the corrole and the first reduction potential of the naphthalene
imide in the arrays respectively (see above), eS = 2.4 is the
dielectric constant of toluene, eP = 25.9 is the dielectric
constant of benzonitrile. RDA
,
the center to center
donor–acceptor distance is 11.7 A for the dyads containing
NI2 and 10.4 A for the dyads containing NI1 and the
ꢀc
This journal is the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2007
New J. Chem., 2007, 31, 247–259 | 251

View Article Online
Table 1 Band maxima and molar absorption coefficients for dyads
and models in toluene solutions, 295 K
lmax/nm
e/104 Mꢁ1 cmꢁ1
NI1
NI2
C1
333
347
334
349
409
428
568
605
639
333
349
409
428
567
604
638
334
350
409
428
568
605
639
412
428
563
612
641
334
348
412
428
563
610
641
333
350
413
428
561
611
640
419
562
617
640
334
349
423
564
616
641
334
350
421
564
618
639
1.28
1.12
1.28
1.16
12.21
10.16
1.82
1.20
0.71
2.61
2.68
12.59
11.34
1.84
1.24
0.75
2.54
2.71
11.90
10.56
1.65
1.15
0.77
12.00
10.67
1.91
1.21
0.70
2.40
2.31
11.72
11.08
1.91
1.21
0.66
2.40
2.33
11.23
10.50
1.81
1.15
0.74
12.05
2.03
1.19
0.96
2.34
2.23
11.51
1.81
1.05
0.77
2.31
2.22
11.19
1.71
1.02
0.86
C1-NI1
C1-NI2
C2
C2-NI1
C2-NI2
C3
C3-NI1
C3-NI2
Fig. 1 Absorption spectra of the dyads and the corresponding models
in toluene; NI1 and NI2 are reported only in the top panel.
Selective excitation of the lowest singlet excited state of the
corrole units in the dyads, 1C-NI, does not lead to any
photoinduced process and results in the decay of the state as
in the isolated molecule, reaction 1, as testified by the lifetime
and emission quantum yield (Table 2). This is quite expected
from Fig. 4, which does not show for the generic dyad C-NI
any state at lower energy that the singlet localized on corrole
1C-NI.
naphthalene imide and corrole radii are rA = 3.5 A and rD
=
5 A, respectively. The results of this calculation yield values of
the CS state energy as follows: C1-NI1 at 2.56 eV, C1-NI2 at
2.62 eV, C2-NI1 at 2.73 eV, C2-NI2 at 2.78 eV, C3-NI1 at
2.81 eV and C3-NI2 at 2.84 eV. These can be approximated for
C1-NI generic dyads to 2.6 eV, for C2-NI to 2.75 eV and for
C3-NI to 2.8 eV and with these values the CS states are
reported in Fig. 4.
Excitation at 350 nm leads with a ca. 50% ratio to the
formation of C-1NI, the singlet excited state localized on
ꢀc
This journal is the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2007
252 | New J. Chem., 2007, 31, 247–259

View Article Online
naphthalene imide. Energy transfer from this state to the
1
singlet excited state localized on corrole C-NI, reaction 2, is
thermodynamically allowed (DG0 = ꢁ1.2 eV) and can there-
fore take place. Accordingly, the lifetime of C-1NI is o10 ps,
indicating a quenching with a rate constant ken 4 1011 sꢁ1
.
The efficiency of energy transfer to the corrole can be calcu-
lated from the relative increase in the emission quantum yield
of the corrole unit in passing from selective excitation at
560 nm to excitation at 350 nm, provided one compares cases
where the same amount of photons is absorbed by the corrole
unit in the dyad and in the reference model. This efficiency is
unity (Table 2, Fig. 3) only for the dyads containing the
corrole C3, C3-NI1 and C3-NI2 whereas the efficiency is ca.
65% for the dyads containing the corrole C2, C2-NI1 and
C2-NI2, and is only ca. 15% in the case of the dyads contain-
ing C1, C1-NI1 and C1-NI2. The energy transfer efficiency
decreases in the order C3-NI 4 C2-NI 4 C3-NI which is the
same order exhibited by the oxidation potentials of corroles
and is in the reverse order with respect to the energy level of
the CS state, see Fig. 4. This leads us to conclude that the
decrease in energy transfer efficiency has to be assigned to a
competition with an electron transfer reaction which occurs in
the excited state C-1NI from the HOMO of the corrole to the
HOMO of the naphthalene imide (Fig. 4, reaction 3), leading
to the generic charge separated state C+-NIꢁ. Reaction 3 is
totally inefficient in the dyads containing corrole C3, a DG0 r
ꢁ0.3 eV for electron transfer is probably insufficient to provide
a rate able to compete with the rapid energy transfer (Fig. 4,
reaction 2). In the case of dyads C2-NI1 and C2-NI2, char-
acterized by a DG0 of ca. ꢁ0.35 eV, electron transfer starts to
compete (15%) with energy transfer and finally becomes
predominant (85%) for dyads C1-NI1 and C1-NI2 where the
electron transfer reaction has a DG0 of ca. ꢁ0.5 eV. It should
be noticed that in spite of the difference in luminescence
Fig. 2 Luminescence spectra of the models in toluene. Top panel:
NI1 (dot) and NI2 (solid) excitation at 350 nm (A = 0.092) in the inset
the 77 K luminescence is reported. Lower panel: C1 (solid), C2 (dash)
and C3 (dot), excitation at 560 nm (A = 0.11).
Table 2 Luminescence data of dyads and models in air-equilibrated toluene at 298 K and in rigid toluene glass at 77 K
295 K
State
77 K
lmax/nm
a
b
l
max/nm
Ffl
Ffl
t/nsc
0.010
—
E/eVd
NI1
NI2
1NI1
ca. 376
—
390
—
650
650
—
650
—
653
654
—
653
—
656
656
—
656
—
—
—
—
—
0.00007
0.015
396
541
394
542
644
647
—
649
—
652
652
—
652
—
654
655
—
3.13
2.29
3.15
2.29
1.93
1.92
—
1.91
—
1.90
1.90
—
1.90
—
1.90
1.89
—
3NI1
—
1NI2
0.245
3NI2
—
—
C1
C1-NI1
1C1
0.22
0.21
—
0.21
—
0.06
0.06
—
0.06
—
0.14
0.14
—
0.13
—
0.22
0.26
5.1
5.0
1C1-NI1
C1-1NI1
1C1-NI2
C1-1NI2
1C2
o0.00005
o 0.010
C1-NI2
0.24
5.0
o0.00005
0.06
0.10
o 0.010
1.7
1.7
C2
C2-NI1
1C2-NI1
C2-1NI1
1C2-NI2
C2-1NI2
1C3
o0.00005
o 0.010
C2-NI2
0.10
1.7
o0.00005
0.14
0.29
o 0.010
3.8
3.9
C3
C3-NI1
1C3-NI1
C3-1NI1
1C3-NI2
C3-1NI2
o0.00005
o 0.010
C3-NI2
0.28
o0.00005
3.7
r 0.010
651
—
1.90
—
a
b
Luminescence quantum yields in air-equilibrated solutions, excitation at 560 nm. For the standard used see Experimental Section. Lumines-
cence quantum yields upon excitation at 350 nm. The yield is calculated by taking into account the photons absorbed by unit of interest, either
c
corrol or imide, only. For the standard used see Experimental Section. Lifetimes detected after excitation at 355 nm for imides and at 560 nm for
d
corroles. Excited states energy levels derived from the luminescence maxima at 77 K.
ꢀc
This journal is the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2007
New J. Chem., 2007, 31, 247–259 | 253

View Article Online
Fig. 4 Energy level diagram for a generic dyad containing naphtha-
lene imide and corrole, C-NI. When differences occur in the energy
levels the components are specified as C1, C2 or C3.
reduced imide has a maximum at ca. 400 nm,30 out of the
wavelength range probed by the experimental set-up used, and
the absorption of corrole cations in the visible and near IR
region24 is not high enough to allow a clear differentiation
from the absorption spectra of the singlet excited state absorb-
ing in the same spectral region.13a We were therefore unable to
clearly detect the charge separated states. It is worth noticing
that C1-NI1 and C1-NI2 displayed, at variance with the other
dyads, some slight instability under the extreme laser peak
power conditions (GW) used in the picosecond pump and
probe experiments. No instability was shown by these and
other dyads in all other experiments, confirming the remark-
able stability of these compounds.
In order to shed light on the energy transfer process 2, we
discuss the rate ken in the frame of the current theories. Energy
transfer between singlet states can occur by two different
mechanisms, the Forster mechanism (or dipole–dipole inter-
¨
action)33 or the Dexter mechanism (or electron exchange).34 In
case of energy transfer between singlet states with high absor-
bance and emission quantum yield the dipole–dipole mechan-
ism, in general, prevails whereas for poorly emitting donor or
absorbing acceptors the Dexter mechanism, based on the
concomitant exchange of two electrons, can prevail. For the
dipole–dipole mechanism it is possible to calculate the rate keFn
by means of the following equation:44
Fig. 3 Luminescence spectra of imides, corroles and dyads in toluene,
excitation at 350 nm, A = 0.1 for corroles and imides and A = 0.2 for
dyads. At 350 nm the absorbance is 50% on corrole and 50% on imide
component.
properties of the imide NI1 compared to NI2, the photoin-
duced processes generated in the dyads from the excited states
localized on the two imides, either C-1NI1 and C-1NI2, are
very similar.
8:8 ꢂ 10ꢁ25k2F
kFen
¼
JF
ð2Þ
This seems to suggest that the excited state 1NI1, though not
n4tR6DA
emissive, has sufficient lifetime to participate in the intra-
1
molecular processes and has an energy level similar to NI2.
in which F and t are the emission quantum yield (0.015 for
NI2 and 7 ꢂ 10ꢁ5 for NI1) and the lifetime (245 ps and 10 ps
for NI2 and NI1, respectively) of the donor, RDA is the
donor–acceptor center-to-center distance (11.7 A for NI2
and 10.4 A for NI1), n is the refractive index of toluene and
JF is the overlap integral. k2, the orientation factor, takes into
The latter fact is important to determine the driving force and
hence the rate of the ensuing reactions. Any attempt to detect
the charge separated states C1+-NI1ꢁ and C1+-NI2ꢁ was
strongly biased by the spectral features of the reduced acceptor
and of the oxidized donor. In fact, the absorbance of the
ꢀc
This journal is the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2007
254 | New J. Chem., 2007, 31, 247–259

View Article Online
account the relative orientation of the transition dipole mo-
ments of the donor and the acceptor and can be simplified to
Experimental section
the statistical value, 2/3. JF, the Forster overlap integral, is
Synthesis
¨
calculated from the overlap between the luminescence spec-
trum of the donor NI2 and NI1, F(uꢀ) (cmꢁ1 units), and the
absorption spectrum e(uꢀ) of the acceptors C1, C2 and C3
(cmꢁ1 units), according to eqn. (3).33
All chemicals were used as received unless otherwise noted.
Reagent grade solvents (CH2Cl2, hexanes, cyclohexane) were
1
distilled prior to use. All reported H NMR and 13C NMR
spectra were recorded on Bruker AM 500 MHz or Varian
400 MHz spectrometers. Chemical shifts (d ppm) were deter-
mined with TMS as the internal reference; J values are given in
Hz. UV-Vis spectra were recorded in toluene (Cary). Chro-
matography was performed on silica (Kieselgel 60, 200–400
mesh), or dry column vacuum chromatography (DCVC)35 was
performed on preparative thin layer chromatography silica
(Merck 107747). Mass spectra were obtained via EI or electro-
spray MS (ESI-MS). The purity of all new corroles was
established based on 1H NMR spectra and elemental analysis.
The following molecules were prepared according to literature
procedures: 5,36 11,23 14,37 15,12a,37 16,37 C3,21d NI138 and
NI2.39
R
ꢀ
ꢀ ꢀ
ꢀ4
FðuÞeðuÞ=u du
JF
¼
ð3Þ
R
FðꢀuÞdꢀu
From the experimental emission and absorption spectra, an
overlap integral JF = 1.46 ꢂ 10ꢁ13 cm3 Mꢁ1, JF = 1.47 ꢂ
10ꢁ13 cm3 Mꢁ1, JF = 1.50 ꢂ 10ꢁ13 cm3 Mꢁ1 is calculated for
dyads C1-NI2, C2-NI2 and C3-NI2, respectively, whereas a JF
= 1.04 ꢂ 10ꢁ13 cm3 Mꢁ1, JF = 1.07 ꢂ 10ꢁ13 cm3 Mꢁ1, JF =
1.14 ꢂ 10ꢁ13 cm3 Mꢁ1 is calculated for dyads C1-NI1, C2-NI1
and C3-NI1, respectively. From eqn. (2) a rate of energy
transfer kFen = 3.5 ꢂ 1011
s
ꢁ1 is derived for the dyads contain-
ing NI2 and a kFen = 7 ꢂ 1010 sꢁ1 is calculated for the dyads
C1-NI1, C2-NI1, C3-NI1. The calculated rates are consistent
with the experimental results for the series C1-NI2, C2-NI2,
C3-NI2, therefore the mechanism could be ascribed to a
dipole–dipole interaction. However, given the uncertainty in
the experimental rate constant we cannot exclude some con-
tribution by a Dexter-type mechanism. On the contrary the
rate calculated according to a Forster mechanism is not in
N-[3-(Hydroxymethyl)phenyl)]-1,8-naphthalimide (9). 1,8-
Naphthalic anhydride (3.96 g, 20 mmol) and amine 7 (2.26
g, 20 mmol) were dissolved in DMF (100 mL). The resulting
mixture was refluxed for 6 h, then it was cooled down and
water (100 mL) was added. The white precipitate was filtered
off, washed with cold EtOH and chromatographed (silica,
CH2Cl2 + 2% MeOH) to afford pure imide 9 (3.3 g, 55%). mp
1
177–178 1C; H NMR (500 MHz; CDCl3; Me4Si) 2.00 (br s,
agreement with the experimental data (ken 4 1011 ꢁ1) for the
s
1H, OH), 4.76 (s, 2H, CH2), 7.24 (m, 1H, C6H4), 7.33 (m, 1H,
C6H4), 7.46–7.49 (m, 1H, C6H4), 7.54 (t, 1H, J = 7.7 Hz,
C6H4), 7.78 (dd, 2H, C10H6), 8.26 (dd, 2H, C10H6), 8.63 (dd,
2H, C10H6); 13C NMR (125 MHz; CDCl3; Me4Si) d 64.8,
122.8, 127.00, 127.02, 127.15, 128.5, 129.5, 131.6, 131.7, 134.3,
135.6, 142.6, 164.3; EI-HR obsd 303.0909 [Mꢃ+], calc. exact
mass 303.0895 (C19H13NO3). Anal. calc. for C19H13NO3: C,
75.24; H, 4.32; N, 4.62. Found: C, 75.22; H, 4.12; N, 4.60%;
IR (KBr): 781, 1242, 1357, 1377, 1588, 1659, 1706, 3445, 3506.
NI1-containing compounds. We have therefore to assume for
the NI1 containing series the contribution by an electron
exchange mechanism in order to explain the results. Within
this mechanism, an electron moves from the half filled LUMO
of the imide unit to the empty LUMO of the corrole unit while
another electron moves from the filled HOMO localized on the
corrole to the half filled HOMO localized on the imide. For
this mechanism the energy transfer rate can be expressed in
classical terms by the following expression:34
N-(3-Formylphenyl)-1,8-naphthalimide (10). Alcohol 9 (3.3
g, 11 mmol) was dissolved in CH2Cl2 (200 mL) followed by
Dess–Martin periodinate (5.03 g, 11 mmol). After stirring for
15 min Na2S2O3 (12 g) dissolved in sat. solution of NaHCO3
(50 mL) was added, and resulting suspension was stirred for
30 min until both phases were clear. Subsequently the organic
phase was separated, washed with NaHCO3 (50 mL) and
water (50 mL), dried with Na2SO4 and evaporated. The pure
aldehyde was obtained after crystallization (CHCl3–hexane),
2.85 g, 95%. mp 210–212 1C; 1H NMR (500 MHz; CDCl3;
Me4Si) 7.59–7.63 (m, 1H, C6H4), 7.72 (t, 1H, J = 7.8 Hz,
C6H4), 7.78–7.83 (m, 2H, C10H6), 7.87 (t, 1H, J = 1.9 Hz,
C6H4), 8.01 (dt, 2H, C6H4), 8.29 (dd, 2H, C10H6), 8.65 (dd,
2H, C10H6), 10.07 (s, 1H, CHO); 13C NMR (125 MHz; CDCl3;
Me4Si) d 122.5, 127.1, 128.5, 129.7, 130.0, 131.8, 134.6, 134.8,
136.3, 137.6, 164.1, 191.1; EI-HR obsd 301.0732 [Mꢃ+], calc.
exact mass 301.0739 (C19H11NO3). Anal. calc. for C19H11NO3:
C, 75.74; H, 3.68; N, 4.65. Found: C, 75.50; H, 3.70; N, 4.57%;
IR (KBr): 779, 1239, 1356, 1376, 1588, 1664, 1705.
4p2H2
kDen
¼
JD
ð4Þ
h
Where H is the intercomponent electronic interaction and
JD is the Dexter overlap integral:
R
FðꢀuÞeðꢀuÞdꢀu
R
R
JD
¼
ð5Þ
ꢀ
ꢀ
ꢀ ꢀ
FðuÞdu eðuÞdu
JD calculated from the spectroscopic data is of the order of
10ꢁ4 cm for all N1 based dyads. By replacing in eqn. (4) this
value and a kDen of 1011 ꢁ1, a value of H of the order of
s
30 cmꢁ1 can be derived. This is a moderate electronic coupling
compatible with the compact structure of the NI1 based dyads,
where the two chromophores are essentially in contact, and
while sufficient to provide a large electron exchange contribu-
tion to the energy transfer process, it would be insufficient to
noticeably perturb the spectroscopic and electrochemical
properties, in agreement with the experimental observations.
N-[4-(5,5-Dimethyl-1,3-dioxan-2-yl)benzyl]-1,8-naphthalimide
(12). 1,8-Naphthalic anhydride (3.96 g, 20 mmol) and acetal
ꢀc
This journal is the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2007
New J. Chem., 2007, 31, 247–259 | 255

View Article Online
11 (5.3 g, 24 mmol) were suspended in EtOH (100 mL). The
resulting mixture was refluxed for 6 h and cooled down. The
white precipitate was filtered off and washed with EtOH to
80.63; H, 5.43; N, 8.41%. labs (toluene, e ꢂ 103) 409 (119),
428 (106), 568 (16.5), 605 (11.5), 639 (7.7) nm.
1
10-[(Benz[de]isoquinoline-1,3-dion-2-yl)-methyl-para-phenyl]-
5,15-bis(2,6-dichlorophenyl)corrole (C2-NI2). The title com-
pound was synthesized according to the procedure described
for C1-NI2, starting from 2,6-dichlorophenyldipyrromethane
(15) (1.16 g, 4.0 mmol) and aldehyde 13 (630 mg, 2.0 mmol).
The reaction mixture was concentrated, filtered through silica
pad (CH2Cl2) and evaporated. The residue was chromato-
graphed (DCVC, silica, CH2Cl2–hexanes, 1 : 1, then 3 : 1),
evaporated and crystallized (CHCl3–MeOH) to afford pure
corrole (300 mg, 17%). Rf = 0.45 (CH2Cl2–hexanes, 3 : 1). 1H
NMR (500 MHz; CDCl3; Me4Si) d (ꢁ3)–(ꢁ1.5) (br s, 3H,
NH), 5.70 (s, 2H, CH2), 7.63 (t, 2H, 8 Hz, C6H3Cl2), 7.75 (d, 8
Hz, 4H, C6H3Cl2), 7.82 (t, 2H, J = 8 Hz, C10H6), 7.90, 8.11
(AA0BB0, J = 8 Hz, 2 ꢂ 2H, C6H4), 8.25 (d, 2H, J = 8 Hz,
C10H6), 8.39 (d, J = 4 Hz, 2H, b-H), 8.47 (d, J = 4.5 Hz, 2H,
b-H), 8.57 (d, J = 4.5 Hz, 2H, b-H), 8.75 (d, 2H, J = 8 Hz,
C10H6), 8.97 (d, J = 4 Hz, 2H, b-H). ESI-LR obsd 872.1 [M +
H+] (C50H30N5Cl4O2); Anal. calc. for C50H29N5Cl4O2: C,
68.74; H, 3.35; N, 8.02. Found: C, 68.59; H, 3.12; N, 7.94.
labs (toluene, e ꢂ 103) 413 (112), 428 (105), 561 (18.1), 611
(11.5), 640 (7.4) nm.
afford pure imide (8.0 g, 100%). mp 256–257 1C (EtOH), H
NMR (500 MHz; CDCl3; Me4Si) d 0.77 (s, 3H, CH3), 1.24 (s,
3H, CH3), 3.60 (d, 10.5 Hz, 2H, CH2O), 3.72 (d, 10.5 Hz, 2H,
CH2O), 5.34 (s, 1H, CH), 5.38 (s, 2H, CH2), 7.44, 7.57
(AA0BB0, J = 8.5 Hz, 2 ꢂ 2H, C6H4), 7.72 (t, 2H, J = 8
Hz, C10H6), 8.18 (d, 2H, J = 8 Hz, C10H6), 8.58 (d, 2H, J = 8
Hz, C10H6); 13C NMR (125 MHz; CDCl3; Me4Si) d 21.9, 23.0,
30.2, 43.3, 77.6, 101.4, 122.7, 126.2, 126.9, 128.1, 129.1, 131.3,
131.6, 134.0, 137.8, 137.8, 164.1; EI-HR obsd 401.1644 [Mꢃ+],
calc. exact mass 401.1627 (C25H23NO4). Anal. calc. for
C25H23NO4: C, 74.79; H, 5.77; N, 3.49. Found: C, 74.66; H,
5.52; N, 3.37%; IR (KBr): 774, 1101, 1235, 1336, 1383, 1656,
1699, 2950.
N-(4-Formylbenzyl)naphthalimide (13). Acetal 12 (8.0 g,
2 mmol) was dissolved in CH2Cl2 (100 mL), then TFA was
added (50 mL) followed by 5% aq H2SO4 (25 mL) and the
whole mixture was vigorously stirred over night at rt. The flask
was placed in an ice-water bath, both acids were neutralized
with diluted NaOH solution, and the resulting suspension was
extracted with CH2Cl2. The organic extracts were evaporated
and residue was crystallized from CHCl3 to obtain the title
compound as off-white crystals (6.3 g, 100%) which were pure
enough for the next step. The pure sample was obtained after
flash chromatography (silica, CH2Cl2) and crystallization
(CHCl3). mp 185–186 1C; 1H NMR (500 MHz; CDCl3; Me4Si)
5.44 (s, 1H, CH), 7.67, 7.82 (AA0BB0, J = 8 Hz, 2 ꢂ 2H,
C6H4), 7.76 (dd, 2H, C10H6), 8.22 (dd, 2H, C10H6), 8.61 (dd,
2H, C10H6), 9.96 (s, 1H, CHO); 13C NMR (125 MHz; CDCl3;
Me4Si) d 43.4, 122.4, 127.0, 128.2, 129.2, 129.9, 131.5, 131.6,
134.3, 135.6, 144.1, 164.1, 191.8; EI-HR obsd 315.0883 [Mꢃ+],
calc. exact mass 315.0895 (C20H13NO3). Anal. calc. for
C25H23NO4: C, 76.18; H, 4.16; N, 4.44. Found: C, 76.29; H,
4.13; N, 4.43%; IR (KBr): 771, 785, 1339, 1383, 1657, 1695.
10-[(Benz[de]isoquinoline-1,3-dion-2-yl)-methyl-para-phenyl]-
5,15-bis(pentafluorophenyl)corrole (C3-NI2). Pentafluorophe-
nyldipyrromethane (16) (1.25 g, 4 mmol) and aldehyde 13
(630 mg, 2 mmol) were dissolved in CH2Cl2 (30 mL). Then
TFA (30 mL, 0.4 mmol) was added and mixture was stirred at
rt for 20 min. The reaction was quenched with the addition of
Et3N (54 mL, 0.4 mmol) in CH2Cl2 (10 mL). DDQ (1.18 g, 5.2
mmol) was dissolved in toluene–CH2Cl2 (1 : 1, 40 mL) and
both mixtures were added simultaneously to the vigorously
stirred CH2Cl2 (50 mL). After 15 min the reaction mixture was
concentrated to 1/4 of initial volume and filtered through silica
pad (CH2Cl2). The fluorescent band was collected, evaporated
and chromatographed (DCVC, silica, CH2Cl2–hexanes, 1 : 1,
then 3 : 1). After evaporation residue was crystallized from
CHCl3–hexanes to afford pure corrole (209 mg, 11%). Rf =
0.42 (CH2Cl2–hexanes, 3 : 1). 1H NMR (500 MHz; CDCl3;
Me4Si) d (ꢁ4)–(ꢁ1.5) (br s, 3H), 5.53 (s, 2H, CH2), 7.68 (t, 2H,
J = 8 Hz, C10H6), 7.82, 8.07 (d + t, AA0BB0 + d, J = 8 Hz, 2
ꢂ 2H + 2H, C6H4 + C10H6), 8.54 (br d, J = 6.3 Hz, 2 + 2H,
b-H + C10H6), 8.63 (d, J = 4.6 Hz, 2H, b-H), 8.66 (d, J = 4.6
Hz, 2H, b-H), 9.07 (d, J = 4 Hz, 2H, b-H). ESI-LR obsd 916.4
[M + H+] (C50H24F10N5O2). Anal. calc. for C50H23F10N5O2:
C, 65.58; H, 2.53; N, 7.65. Found: C, 65.72; H, 2.63; N, 7.54%.
labs (toluene, e ꢂ 103) 421 (112), 564 (17.1), 618 (10.2), 639
(8.6) nm.
10-[(Benz[de]isoquinoline-1,3-dion-2-yl)-methyl-para-phenyl]-
5,15-bis(mesityl)corrole (C1-NI2). Mesityldipyrromethane (14)
(1.06 g, 4.0 mmol) and aldehyde 13 (630 mg, 2.0 mmol) were
dissolved in CH2Cl2 (30 mL). Then TFA (3 mL, 0.04 mmol)
was added and mixture was stirred at rt for 7 h. para-Chloranil
(1.47 g, 6.0 mmol) was added and stirring was continued for 16
h. The reaction mixture was concentrated to 1/4 of initial
volume and filtered through silica pad (CH2Cl2–hexanes, 3 :
1). The fluorescent band was collected, and was chromato-
graphed (DCVC, silica, CH2Cl2–hexanes, 1 : 1, then 3 : 1).
After evaporation it was crystallized from CHCl3–MeOH to
afford pure corrole (262 mg, 16%). Rf = 0.48 (CH2Cl2–hex-
anes, 3 : 1). 1H NMR (500 MHz; CDCl3; Me4Si) d (ꢁ3)–(ꢁ1.5)
(br s, 3H), 1.89 (s, 12H, o-CH3 Mes), 2.57 (s, 6H, p-CH3 Mes),
5.67 (s, 2H, CH2), 7.23 (s, 4H, Mes), 7.79 (dd, 2H, C10H6),
7.87, 8.08 (AA0BB0, J = 8 Hz, 2 ꢂ 2H, C6H4), 8.23 (dd, 2H,
C10H6), 8.28 (d, J = 4 Hz, 2H, b-H), 8.42 (d, J = 4.5 Hz, 2H,
b-H), 8.46 (d, J = 4.5 Hz, 2H, b-H), 8.70 (dd, 2H, C10H6), 8.85
(d, J = 4 Hz, 2H, b-H). ESI-HR obsd 820.3677 [M + H+],
calc. exact mass 820.3646 (C56H46N4O2); Anal. calc. for
C56H45N4O2 ꢄ H2O: C, 80.26; H, 5.65; N, 8.36. Found: C,
10-[(Benz[de]isoquinoline-1,3-dion-2-yl)-meta-tolyl]-5,15-bis
(mesityl)corrole (C1-NI1). The title compound was synthesized
according to the procedure described for C1-NI2, starting
from mesityldipyrromethane 14 (1.06 g, 4 mmol) and aldehyde
10 (602 mg, 2 mmol). The reaction mixture was concentrated,
filtered through silica pad (CH2Cl2) and evaporated. The
residue was chromatographed (DCVC, silica, CH2Cl2–
hexanes, 1 : 1, then 3 : 1), evaporated and crystallized
(CHCl3–MeOH) to afford pure corrole (92 mg, 6%).
ꢀc
This journal is the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2007
256 | New J. Chem., 2007, 31, 247–259

View Article Online
Rf = 0.39 (CH2Cl2–hexanes, 3 : 1). 1H NMR (500 MHz;
CDCl3; Me4Si) d (ꢁ3) ꢁ (ꢁ1) (br s, 3H, NH), 1.89 (s, 6H,
o-CH3 Mes), 1.96 (s, 6H, o-CH3 Mes), 2.57 (s, 6H, p-CH3 Mes),
7.25 (s, 2H, Mes), 7.29 (s, 2H, Mes), 7.68 (d, J = 8 Hz, 1H,
C6H4), 7.81 (t, 2H, J = 8 Hz, C10H8), 7.91 (t, 1H, J = 8 Hz,
C6H4), 8.17 (s, 1H, C6H4), 8.26 (d, J = 8 Hz, 2H, C10H6), 8.29
(d, J = 8 Hz, 1H, C6H4), 8.33 (d, J = 4 Hz, 2H, b-H), 8.55 (d, J
= 4.5 Hz, 2H, b-H), 8.70 (d, 2H, J = 8 Hz, C10H6), 8.76 (d, J
= 4.5 Hz, 2H, b-H), 8.88 (d, J = 4 Hz, 2H, b-H). ESI-HR obsd
806.3482 [M + H+], calc. exact mass 806.3489 (C55H44N5O2);
Anal. calc. for C55H43N5O2: C, 81.96; H, 5.38; N, 8.69. Found:
C, 81.85; H, 5.55; N, 8.85. labs (toluene, e ꢂ 103) 409 (126), 428
(113), 567 (18.4), 604 (12.4), 638 (7.5) nm.
(20 mL) in water (200 mL) was added and the resulting
suspension was stirred at rt for 2 h. After extraction with
CHCl3 (2 ꢂ 50 mL), the organic phase was washed with water
(2 ꢂ 50 mL), diluted to the volume of 250 mL, and para-
chloranil (1.476 g, 6 mmol) was added in one portion. The
resulting mixture was stirred at rt for 16 h and then solvent
was removed to 1/4 of the initial volume. After filtration
through silica pad (CH2Cl2–hexanes, 1 : 1), hydrazine (1 M
solution in THF, 300 mL, 300 mmol) was added to the fractions
contained desired corrole. After evaporation, the residue was
chromatographed (DCVC, silica, CH2Cl2–hexanes, 1 : 9) and
crystallized from cyclohexane–MeOH to afford pure corrole
1
(52 mg, 4%). Rf = 0.46 (CH2Cl2–hexanes, 2 : 3). H NMR
(500 MHz; CDCl3; Me4Si) d (ꢁ2.5)–(ꢁ1.5) (br s, 3H, NH),
1.92 (s, 12H, o-CH3 Mes), 2.59 (s, 6H, p-CH3 Mes), 2.65 (s,
3H, CH3 Tol), 7.25 (s, 4H, Mes), 7.51, 8.03 (AA0BB0, J = 8
Hz, 2 ꢂ 2H, C6H4), 8.31 (d, J = 4 Hz, 2H, b-H), 8.47 (d, J =
4.5 Hz, 2H, b-H), 8.49 (d, J = 4.5 Hz, 2H, b-H), 8.87 (d, J = 4
Hz, 2H, b-H). ESI-HR obsd 625.3307 [M + H+], calc. exact
mass 625.3325 (C44H41N4); Anal. calc. for C44H40N4: C, 84.58;
H, 6.45; N, 8.97. Found: C, 84.39; H, 6.49; N, 8.85%. labs
(toluene, e ꢂ 103) 409 (122), 428 (102), 568 (18.2), 605 (12.0),
639 (7.1) nm.
10-[(Benz[de]isoquinoline-1,3-dion-2-yl)-meta-tolyl]-5,15-bis
(2,6-dichlorophenyl)corrole (C2-NI1). The title compound
was synthesized according to the procedure described for
C1-NI2, starting from 2,6-dichlorophenyldipyrromethane 15
(1.16 g, 4 mmol) and aldehyde 10 (602 mg, 2 mmol). The
reaction mixture was concentrated, filtered through silica pad
(CH2Cl2) and evaporated. The residue was chromatographed
(DCVC, silica, CH2Cl2–hexanes, 1 : 1, then 3 : 1), evaporated
and crystallized (CHCl3–MeOH) to afford pure corrole (372
mg, 22%). Rf = 0.39 (CH2Cl2–hexanes, 3 : 1). 1H NMR (500
MHz; CDCl3; Me4Si) d (ꢁ2.5)–(ꢁ1.5) (br s, 3H, NH), 7.61 (t,
2H, 8 Hz, C6H3Cl2), 7.67 (m, 1H, C6H4), 7.70–7.77 (m, 4H +
2H, C6H3Cl2 + C10H6), 7.90 (t, 1H, J = 8 Hz, C6H4),
8.15–8.18 (m, 2H + 1H, C10H6 + C6H4), 8.28–8.31 (m,
1H, C6H4), 8.39 (d, J = 4 Hz, 2H, b-H), 8.58 (d, J = 4.5 Hz,
2H, b-H), 8.66 (dd, 2H, C10H6), 8.85 (d, J = 4.5 Hz, 2H, b-
10-(4-Tolyl)-5,15-bis(2,6-dichlorophenyl)corrole (C2). The
title compound was synthesized according to the procedure
described for C1, starting from 2,6-dichlorophenyldipyrro-
methane 15 (1.16 g, 4.0 mmol) and 4-tolualdehyde (240 mL,
2.0 mmol). The reaction mixture was concentrated, filtered
through silica pad (CH2Cl2–hexanes, 1 : 1) and evaporated.
The residue was chromatographed (DCVC, silica,
CH2Cl2–hexanes, 1 : 9) and crystallized (cyclohexane–MeOH)
to afford pure corrole (162 mg, 12%). Rf = 0.43 (CH2Cl2–hex-
anes, 2 : 3). 1H NMR (500 MHz; CDCl3; Me4Si) d (ꢁ4) ꢁ (ꢁ1)
(br s, 3H, NH), 2.66 (s, 3H, CH3 Tol), 7.52, 8.05 (AA0BB0, J =
8 Hz, 2 ꢂ 2H, C6H4), 7.62 (t, 2H, 8 Hz, C6H3Cl2), 7.75 (d, 8
Hz, 4H, C6H3Cl2), 8.40 (d, J = 4 Hz, 2H, b-H), 8.51 (d, J =
4.5 Hz, 2H, b-H), 8.60 (d, J = 4.5 Hz, 2H, b-H), 8.98 (d, J = 4
Hz, 2H, b-H). ESI-HR obsd 677.0862 [M + H+], calc. exact
ꢃ
+
H), 8.97 (d, J = 4 Hz, 2H, b-H). EI-LR obsd 857.3 [M
]
(C49H28N5Cl4O2); Anal. calc. for C49H27N5Cl4O2: C, 68.74;
H, 3.35; N, 8.02. Found: C, 68.59; H, 3.12; N, 7.94%. labs
(toluene, e ꢂ 103) 412 (117), 428 (110), 563 (19.1), 610 (12.1),
641 (6.6) nm.
10-[(Benz[de]isoquinoline-1,3-dion-2-yl)-meta-tolyl]-5,15-bis
(pentafluorophenyl)corrole (C3-NI1). The title compound was
synthesized according to the procedure described for C1-NI2,
starting from pentafluorophenyldipyrromethane 16 (1.16 g, 4
mmol) and aldehyde 10 (602 mg, 2 mmol). The reaction
mixture was concentrated, filtered through silica pad (CH2Cl2)
and evaporated. The residue was chromatographed (DCVC,
silica, CH2Cl2–hexanes, 1 : 1, then 3 : 1), evaporated and
crystallized (CHCl3–hexanes) gave pure corrole (404 mg,
22%). Rf = 0.39 (CH2Cl2–hexanes, 3 : 1).1H NMR (500
MHz; CDCl3; Me4Si) d (ꢁ4)–(ꢁ1.5) (br s, 3H), 7.63–7.66
(m, 1H, C6H4), 7.67 (t, 2H, J = 8 Hz, C10H6), 7.91 (t, J =
8 Hz, 1H, C6H4), 8.07 (dd, 2H, C10H6), 8.14 (t, J = 2 Hz, 1H,
C6H4), 8.25–8.28 (m, 1H, C6H4), 8.54 (br d, J = 4 Hz, 2H, b-
H), 8.57 (dd, 2H, C10H6), 8.75 (d, J = 4.6 Hz, 2H, b-H), 8.93
(d, J = 4.6 Hz, 2H, b-H), 9.07 (d, J = 4 Hz, 2H, b-H). ESI-LR
obsd 902.3 [M + H+] (C49H22F10N5O2). Anal. calc. for
C49H21F10N5O2: C, 65.27; H, 2.35; N, 7.77. Found: C, 65.38;
H, 2.15; N, 7.74%. labs (toluene, e ꢂ 103) 423 (115), 564 (18.1),
616 (10.5), 641 (7.7) nm.
mass
677.0829
(C38H26N4Cl4);
Anal.
calc.
for
C38H25N4Cl4 ꢄ H2O: C, 65.53; H, 3.76; N, 8.04. Found: C,
65.50; H, 3.57; N, 7.90%. labs (toluene, e ꢂ 103) 412 (120), 428
(106), 563 (19.1), 612 (12.1), 641 (7.0) nm.
Spectroscopy and photophysics
Spectrophotometric grade toluene at 295 K and at 77 K was
used without further purification. Standard 10 mm fluores-
cence cells were used at 295 K whereas experiments at 77 K
made use of capillary tubes in a home made quartz Dewar
filled with liquid nitrogen. Due to geometrical conditions at 77
K the absolute quantum yield cannot be determined. If not
otherwise specified, solutions were air-equilibrated. A Perkin-
Elmer Lambda 5 UV/Vis spectrophotometer and a Spex
Fluorolog II spectrofluorimeter were used to acquire absorp-
tion and emission spectra. Reported luminescence spectra are
uncorrected, unless otherwise specified. Emission quantum
yields were determined after correction for the photomultiplier
response, with reference to air-equilibrated toluene solutions
of TPP with a Ffl = 0.1140 or to quinine sulfate in 1N sulfuric
10-(4-Tolyl)-5,15-bis(mesityl)corrole (C1). Mesityldipyrro-
methane (1.06 g, 4.0 mmol) and 4-tolualdehyde (240 mL, 2.0
mmol) were dissolved in MeOH (400 mL). Then conc. HClaq
ꢀc
This journal is the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2007
New J. Chem., 2007, 31, 247–259 | 257

View Article Online
acid with Ffl = 0.546.41 Luminescence lifetimes in the nano-
second range were obtained with an IBH single photon
counting equipment with excitation at 560 nm from a pulsed
diode source (resolution 0.3 ns). For determination of emis-
sion lifetimes in the picosecond range an apparatus based on a
Nd:YAG laser (35 ps pulse duration, 355 nm, 1.5 mJ) and a
Streak Camera with overall resolution of 10 ps was used.42
Attempts to determine the CS spectra and lifetimes in the
picosecond range were performed by a pump–probe apparatus
with 30 ps resolution based on a Nd-YAG laser (355 nm or
532 nm, 3 mJ, 35 ps pulse duration, 10 Hz) and an optical
multichannel analizer (Roper Scientific, Acton Research, Ac-
ton MA), further details on the experimental set-up were
reported previously.43 The stability of solutions was carefully
checked after each experiment by spectrophotometric control
and, unless otherwise specified, the samples were perfectly
stable. Experimental uncertainties are estimated to be within
10% for lifetime determination, 15% for quantum yields, 20%
for molar absorption coefficients and 3 nm for emission and
absorption peaks. The temperature of operation was 295 K
except otherwise stated. Computation of the integral overlaps
and of the rate for the energy transfer processes according to
100% in the dyads containing the corrole more difficult to
oxidize to 65% and 15% in the dyads containing corrole with
progressively lower oxidation potentials whereas electron
transfer efficiency follows the reverse pattern. Energy transfer
is discussed in the frame of current theories; a dipole–dipole
mechanism could explain the process in dyads containing the
imide NI2, though we cannot exclude a contribution by an
electron exchange mechanism. A large contribution by an
electron exchange mechanism is proposed in dyads containing
the non emitting imide NI1. Excitation in the corrole manifold
yields an excited state which does not display any intramole-
cular reactivity due to its low energy.
These systems represent one of the few examples of photo-
stable corrole based arrays exhibiting intramolecular photo-
induced energy transfer13b,14e and the first example of corrole-
based molecular ensembles displaying photoinduced electron
transfer. This confirms the suitability of corrole unit as a
building block for molecular architectures displaying function-
ality driven by light energy.
Acknowledgements
We thank Volkswagen Foundation, Polish Ministry of Science
and Education, CNR of Italy (Project: Componenti moleco-
lari e supramolecolari o macromolecolari con proprieta foto-
niche ed optoelettroniche) and Ministero dell’Istruzione,
Forster and Dexter mechanism were performed with the use of
¨
Matlab 5.2.44
Electrochemistry
dell’Universita’
e
della Ricerca of Italy (FIRB,
Benzonitrile (PhCN, 99.9% CHROMASOLV from Sigma-
Aldrich) was distilled over P2O5 under vacuum prior to use.
Vacuum-dried tetra-n-butylammonium perchlorate (TBAP,
electrochemical grade from Fluka) was used as supporting
electrolyte (c = 0.1 M). The concentration of reactants was
0.5 mM.
RBNE019H9K) for financial support.
References
1 (a) G. McDermott, S. M. Prince, A. A. Freer, A. M.
Hawthornthwaite-Lawless, M. Z. Papiz, R. J. Cogdell and N.
W. Isaacs, Nature, 1995, 374, 517–520; (b) A. W. Roszak, T. D.
Howard, J. Southall, A. T. Gardiner, C. J. Law, N. W. Isaacs and
R. J. Cogdell, Science, 2003, 302, 1969–1972; (c) A. Ben-Shem, F.
Frolow and N. Nelson, Nature, 2003, 426, 630–635; (d) D. Gust,
T. A. Moore and A. L. Moore, Acc. Chem. Res., 2001, 34, 40–48;
(e) M. R. Wasielewski, Chem. Rev., 1992, 92, 435–461; (f) J. H.
Alstrum-Avecedo, M. K. Brennaman and T. J. Meyer, Inorg.
Chem., 2005, 44, 6802–6827; (g) M. R. Wasielewski, J. Org.
Chem., 2006, 71, 5051–5066.
2 (a) S. L. Gould, G. Kodis, P. A. Liddell, R. E. Palacios, A. Brune,
D. Gust, T. A. Moore and A. L. Moore, Tetrahedron, 2006, 62,
2074–2096; (b) R. H. Goldsmith, L. E. Sinks, R. F. Kelley, L. J.
Betzen, W. Liu, E. A. Weiss, M. A. Ratner and M. R. Wasie-
lewski, Proc. Natl. Acad. Sci. U. S. A., 2005, 102, 3540–3545.
3 (a) D. Gust and T. A. Moore, in The Porphyrin Handbook, ed. K.
M. Kadish, K. M. Smith and R. Guilard, Academic Press, New
York, 2000, vol. 8, pp. 153–190; (b) D. Holten, D. F. Bocian and
J. S. Lindsey, Acc. Chem. Res., 2002, 35, 57–69; (c) H. Imahori, J.
Phys. Chem. B, 2004, 108, 6130–6143; (d) Y. Kobuke and K.
Ogawa, Bull. Chem. Soc. Jpn., 2003, 76, 689–708; (e) K. Kilsa, J.
Kajanus, S. Larsson, A. N. Macpherson, J. Martensson and B.
Albinsson, Chem.–Eur. J., 2001, 7, 2122–2133.
Cyclic voltammetry was carried out with a EG&G PAR
273A potentiostat controlled by a PC computer by means of
the software M270 from PAR. The positive feedback method
of iR compensation was applied. A three-electrode cell was
used consisting of a platinum-disk working electrode (1.5 mm
diameter), a platinum counter electrode and a saturated
calomel reference electrode (SCE). All potentials are referred
against SCE. The solution was deoxygenated with argon and a
blanket of gas was maintained over the solution surface during
measurements.
Conclusions
Our studies have clearly documented the ability of the
dipyrromethane + aldehyde strategy to assemble corrole
skeletons with more elaborated substituents. By using this
sequence, corrole dyads could be prepared from commercially
available reagents in just 2–5 steps. Respective aldehydes were
generated in simple synthetic pathways.
4 (a) S. G. DiMagno, V. S.-Y. Lin and M. J. Therien, J. Org.
Chem., 1993, 58, 5983–5993; (b) M. O. Senge and I. Bischoff, Eur.
J. Org. Chem., 2001, 1735–1751; (c) J. S. Lindsey, in The
Porphyrin Handbook, ed. K. M. Kadish, K. M. Smith and R.
Guilard, Academic Press, New York, 2000, vol. 1, pp. 45–118; (d)
M. O. Senge and J. Richter, J. Porphyrins Phthalocyanines, 2004,
8, 934–953; (e) K. M. Smith and M. G. H. Vicente, in Science of
Synthesis, ed. S. M. Weinreb, Georg Thieme Verlag, Stuttgart,
New York, 2004, pp. 1081–1235.
The dyads have been spectroscopically and photophysical
characterized and display an excellent stability in toluene.
When the system is excited in the naphthalene imide manifold,
the ensuing singlet excited state has enough energy to display
intramolecular reactivity. Competitive energy and electron
transfer have been evidenced, the relative weight of the two
processes being determined by the driving force for charge
separation. The energy transfer efficiency decreases from
5 K. Kalyanasundaram, Photochemistry of Polypyridine and Por-
phyrin Complexes, Academic Press, London, 1992, part III, pp.
369–603, and references therein.
ꢀc
This journal is the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2007
258 | New J. Chem., 2007, 31, 247–259

View Article Online
6 (a) X. Li, L. E. Sinks, B. Rybtchinski and M. R. Wasielewski, J.
Am. Chem. Soc., 2004, 126, 10810–10811; (b) D. M. Guldi, I.
Zilbermann, A. Gouloumis, P. Vazquez and T. Torres, J. Phys.
Chem. B, 2004, 108, 18485–18494; (c) D. M. Guldi and H.
Imahori, J. Porphyrins Phthalocyanines, 2004, 8, 976–983.
7 (a) D. Gonzalez-Rodriguez, T. Torres, D. M. Guldi, J. Rivera, M.
A. Herranz and L. Echegoyen, J. Am. Chem. Soc., 2004, 126,
6301–6313; (b) D. Gonzalez-Rodriguez, C. G. Claessens, T.
Torres, S. G. Liu, L. Echegoyen, N. Vila and S. Nonell,
Chem.–Eur. J., 2005, 11, 3881–3893.
17 (a) I. Saito, Pure Appl. Chem., 1992, 64, 1305–1310; (b) M.
Licchelli, A. O. Biroli, A. Poggi, D. Sacchi, C. Sangermani and
M. Zema, Dalton Trans., 2003, 4537–4545.
18 (a) Q. Tan, D. Kaciaukas, S. Lin, S. Stone, A. L. Moore, T. A.
Moore and D. Gust, J. Phys. Chem. B, 1997, 101, 5214–5223; (b)
D. W. Cho, M. Fujitsuka, A. Sugimoto, U. C. Yoon, P. S.
Mariano and T. Majima, J. Phys. Chem. B, 2006, 110,
11062–11068; (c) T. P. Le, J. E. Rogers and L. A. Kelly, J. Phys.
Chem. A, 2000, 104, 6778–6785; (d) S. Abad, M. Kluciar, M. A.
Miranda and U. Pischel, J. Org. Chem., 2005, 70, 10565–10568.
19 (a) W. H. Zhu, H. Tian, E. Q. Gao, M. Z. Yang and K. Muellen,
Chem. Lett., 2000, 7, 778–779; (b) H. Tian, P. H. Liu, W. H. Zhu,
E. Q. Gao, W. A. Da-Jun and S. M. Cai, J. Mater. Chem., 2000,
10, 2708–2715; (c) A. S. Lukas, P. J. Bushard and M. R.
Wasielewski, J. Am. Chem. Soc., 2001, 123, 2440–2441; (d) T.
Gunlaugsson, T. C. Lee and R. Parkesh, Org. Biomol. Chem.,
2003, 1, 3265–3267.
8 (a) T. S. Balaban, H. R. Tamiaki and A. Holzwarth, ‘Supramo-
lecular Dye Chemistry’, , in Topics in Current Chemistry, ed. F.
Wurthner, , Springer, Berlin, 2005, vol. 258, pp. 1–38; (b) T. S.
¨
Balaban, Acc. Chem. Res., 2005, 38, 612–623.
9 (a) V. Huber, M. Katterle, M. Lysetska and F. Wurthner, Angew.
¨
Chem., Int. Ed., 2005, 44, 3147–3151; (b) S. Sasaki, T. Mizoguchi
and H. Tamiaki, Tetrahedron, 2005, 61, 8041–8048; (c) R. F.
Kelley, M. J. Tauber and M. R. Wasielewski, J. Am. Chem. Soc.,
20 R. W. Middleton, J. Parrick, E. D. Clarke and P. Wardman, J.
Heterocycl. Chem., 1986, 23, 849–855.
2006, 128, 4779–4791; (d) C. Roger, M. G. Muller, M. Lysetska,
¨
¨
Y. Miloslavina, A. R. Holzwarth and F. Wurthner, J. Am. Chem.
¨
21 (a) D. T. Gryko and K. Jadach, J. Org. Chem., 2001, 66,
4267–4275; (b) D. T. Gryko and K. E Piechota, J. Porphyrins
Phthalocyanines, 2002, 6, 81–97; (c) D. T. Gryko and B. Koszar-
na, Org. Biomol. Chem., 2003, 1, 350–357; (d) D. T. Gryko and B.
Koszarna, Synthesis, 2004, 2205–2209.
Soc., 2006, 128, 6542–6543.
10 (a) N. Mataga, S. Taniguchi, H. Chosrowjan, A. Osuka and N.
Yoshida, Photochem. Photobiol. Sci., 2003, 2, 493–500; (b) I. W.
Hwang, T. Kamada, T. K. Ahn, D. M. Ko, T. Nakamura, A.
Tsuda, A. Osuka and D. Kim, J. Am. Chem. Soc., 2004, 126,
16187–16198; (c) I. W. Hwang, N. Aratani, A. Osuka and D.
Kim, Bull. Korean Chem. Soc., 2005, 26, 19–31.
11 (a) R. Paolesse, in The Porphyrin Handbook, ed. K. M. Kadish, K.
M. Smith and R. Guilard, Academic Press, New York, 2000, vol.
2, pp. 201–232; (b) D. T. Gryko, Eur. J. Org. Chem., 2002,
1735–1742; (c) R. Guilard, J.-M. Barbe, C. Stern and K. M.
Kadish, in The Porphyrin Handbook, ed. K. M. Kadish, K. M.
Smith and R. Guilard, Elsevier Science (U. S. A.), vol. 18,
pp. 303–351; (d) D. T. Gryko, J. P. Fox and D. P. Goldebrg,
J. Porphyrins Phthalocyanines, 2004, 8, 1091–1105; (e) S. Nardis,
D. Monti and R. Paolesse, Mini-Rev. Org. Chem., 2005, 2,
355–372.
12 (a) B. Koszarna and D. T. Gryko, J. Org. Chem., 2006, 71,
3707–3717; (b) J.-M. Barbe, G. Canard, S. Brandes and R.
Guilard, Eur. J. Org. Chem., 2005, 4601–4611.
13 (a) B. Ventura, A. Degli Esposti, B. Koszarna, D. T. Gryko and
L. Flamigni, New J. Chem., 2005, 29, 1559–1566; (b) L. Flamigni,
B. Ventura, M. Tasior and D. T. Gryko, Inorg. Chim. Acta,
2006DOI: 10.1016/j.ica.2006.03.021.
22 W. Gelmo, J. Prakt. Chem., 1913, 88, 818–831.
23 H. Imahori, K. Tamaki, Y. Araki, T. Hasobe, O. Ito, A.
Shimomura, S. Kundu, T. Okada, Y. Sakata and S. Fukuzumi,
J. Phys. Chem. A, 2002, 106, 2803–2814.
24 J. Shen, J. Shao, Z. Ou, W. E, B. Koszarna, D. T. Gryko and K.
M. Kadish, Inorg. Chem., 2006, 45, 2251–2265.
25 P. Valat, V. Wintgens, J. Kossanyi, L. Biczok, A. Demeter and T.
´
Berces, J. Am. Chem. Soc., 1992, 114, 946–953.
´
26 S. K. Lee, Y. Zu, A. Herrmann, Y. Geerts, K. Mullen and A. J.
¨
Bard, J. Am. Chem. Soc., 1999, 121, 3513–3520.
27 J. E. Rogers, S. J. Weiss and L. A. Kelly, J. Am. Chem. Soc., 2000,
122, 427–436.
28 Y. O. Su, K.-Y. Chiu, T.-H. Lin, S.-J. Shieh and S.-C. Lin, J. Org.
Chem., 2005, 70, 4323–4331.
29 M. J. Ahrens, M. J. Tauber and M. R. Wasielewski, J. Org.
Chem., 2006, 71, 2107–2114.
´ ´
30 A. Demeter, L. Biczok, T. Berces, V. Wintgens, P. Valat and J.
Kossanyi, J. Phys. Chem., 1993, 97, 3217–3224.
31 A. Weller, Z. Phys. Chem., Neue Folge, 1982, 133, 93–98.
32 (a) S. R. Greenfield, W. A. Svec, D. Gosztola and M. R.
Wasielewski, J. Am. Chem. Soc., 1996, 118, 6767–6777; (b) L.
14 (a) J. Bendix, I. J. Dmochowski, H. B. Gray, A. Mahammed, L.
Simkhovic and Z. Gross, Angew. Chem., Int. Ed., 2000, 39,
4048–4051; (b) R. Paolesse, A. Marini, S. Nardis, A. Froiio,
F. Mandoj, D. J. Nurco, L. Prodi, M. Montalti and K. M.
Smith, J. Porphyrins Phthalocyanines, 2003, 7, 25–36; (c) J. J.
Weaver, K. Sorasaenee, M. Sheikh, R. Goldschmidt, E. Tkachen-
ko, Z. Gross and H. B. Gray, J. Porphyrins Phthalocyanines,
Flamigni, B. Ventura, C.-C. You, C. Hippius and F. Wurthner, J.
Phys. Chem. C, DOI: 10.1021/jp065394g.
¨
33 Th. Forster, Discuss. Faraday Soc., 1959, 27, 7–17.
¨
34 D. L. Dexter, J. Chem. Phys., 1953, 21, 836–850.
35 D. S. Pedersen and C. Rosenbohm, Synthesis, 2001, 2431–2434.
36 A. D. Andricopulo, L. A. Mueller, V. C. Filho, G. S. Cani, J. F.
Roos, R. Correa, A. R. S. Santos, R. J. Nunes and R. A. Yunes,
Farmaco, 2000, 55, 319–321.
37 (a) B. J. Littler, M. A. Miller, C. H. Hung, R. W. Wagner, D. F.
O’Shea, P. D. Boyle and J. S. Lindsey, J. Org. Chem., 1999, 64,
1391–1396; (b) J. K. Laha, S. Dhanalekshmi, M. Taniguchi, A.
Ambroise and J. S. Lindsey, Org. Process Res. Dev., 2003, 7,
799–812.
2004, 8, 76–81; (d) T. Ding, E. A. Aleman, D. A. Mordarelli and
´
C. J. Ziegler, J. Phys. Chem. A, 2005, 109, 7411–7417; (e) J.
Poulin, C. Stern, R. Guilard and P. D. Harvey, Photochem.
Photobiol., 2006, 82, 171–176; (f) R. Paolesse, F. Sagone, A.
Macagnano, T. Boschi, L. Prodi, M. Montalti, N. Zaccheroni,
F. Bolletta and K. M. Smith, J. Porphyrins Phthalocyanines, 1999,
3, 364–370.
15 (a) T. Van der Boom, R. T. Hayes, Y. Zhao, P. J. Bushard, E. A.
Weiss and M. R. Wasielewski, J. Am. Chem. Soc., 2002, 124,
9582–9590; (b) K. Tomizaki, R. S. Loewe, C. Kirmaier, J. K.
Scwartz, J. L. Retsek, D. F. Bocian, D. Holten and J. S. Lindsey,
J. Org. Chem., 2002, 67, 6519–6534; (c) K. Okamoto, Y. Mori, H.
Yamada, H. Imahori and S. Fukuzumi, Chem.–Eur. J., 2004, 10,
474–483.
16 (a) V. Wintgens, P. Valat, J. Kossanyi, L. Biczok, A. Demeter and
T. Berces, J. Chem. Soc., Faraday Trans., 1994, 90, 411–421; (b)
A. Samanta, B. Ramachandram and G. Saroja, J. Photochem.
Photobiol., A, 1996, 101, 29–32.
38 H. Cao, V. Chang, R. Hernandez and M. D. Heagy, J. Org.
Chem., 2005, 70, 4929–4934.
39 T. Sakamoto and C. Pac, J. Org. Chem., 2001, 66, 94–98.
40 P. G. Seybold and M. J. Gouterman, J. Mol. Spectrosc., 1969, 31,
1–13.
41 D. F. Eaton, Pure Appl. Chem., 1988, 60, 1107–1114.
42 L. Flamigni, J. Phys. Chem., 1993, 97, 9566–9572.
43 L. Flamigni, A. M. Talarico, S. Serroni, F. Puntoriero, M. J.
Gunter, M. R. Johnston and T. P. Jeynes, Chem.–Eur. J., 2003, 9,
2649–2659.
44 Matlab 5.2, The MathWorks Inc., Natik, MA 01760, USA, 1998.
ꢀc
This journal is the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2007
New J. Chem., 2007, 31, 247–259 | 259