Singlet-energy transfer in quadruple hydrogen-bonded oligo(p-phenylenevinylene)perylene-diimide dyads

Article abstract of DOI:10.1039/b208824j

The photophysical properties of a supramolecular donor-acceptor dyad consisting of an oligo(p-phenylenevinylene) unit and a perylene-diimide unit are described. The dyad is created by functionalising the two chromophores with quadruple hydrogen bonding 2-ureido-4[1H]-pyrimidinone units, which provide a high association constant (K ≈ 10⁸ M^-1 in toluene). This feature enabled us to study the time-resolved photoinduced singlet-energy transfer reaction between the two chromophores in dilute solution with transient pump-probe spectroscopy. This energy transfer occurs with a time constant of 5.1 ps.

Full text of DOI:10.1039/b208824j

View Article Online / Journal Homepage / Table of Contents for this issue
Singlet-energy transfer in quadruple hydrogen-bonded
oligo(p-phenylenevinylene)perylene-diimide dyads
Edda E. Neuteboom, Edwin H. A. Beckers, Stefan C. J. Meskers, E. W. Meijer and
René A. J. Janssen*
Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology,
P.O. Box 513, 5600 MB Eindhoven, The Netherlands. E-mail: r.a.j.janssen@tue.nl
Received 10th September 2002, Accepted 12th November 2002
First published as an Advance Article on the web 29th November 2002
The photophysical properties of a supramolecular donor–acceptor dyad consisting of an oligo(p-phenylenevinylene)
unit and a perylene-diimide unit are described. The dyad is created by functionalising the two chromophores with
quadruple hydrogen bonding 2-ureido-4[1H]-pyrimidinone units, which provide a high association constant (K ≈ 108
M
Ϫ1 in toluene). This feature enabled us to study the time-resolved photoinduced singlet-energy transfer reaction
between the two chromophores in dilute solution with transient pump-probe spectroscopy. This energy transfer
occurs with a time constant of 5.1 ps.
and study its photophysical properties in hetero-assemblies
Introduction
with OPV-UP (Fig. 1) using fluorescence spectroscopy and
femtosecond pump-probe spectroscopy. The high association
constant of the heterodimer allowed us to time resolve the
singlet-energy transfer reaction in this supramolecular system
by femtosecond pump-probe spectroscopy.
Non-covalent interactions between organic molecules are
ubiquitous in nature and serve to assemble, position and organ-
ize extended architectures that fulfil complex functions. The
photosynthetic reaction centre is an intriguing example of such
a structural design. Here, photoinduced energy and electron
transfer reactions between carefully aligned molecular arrays of
photo- and redox-active components work in concert to convert
and store solar energy.1 Because hydrogen bonding is often a
key element in structuring the natural systems, the study of
photoinduced energy and electron transfer reactions between
donors and acceptors assembled via hydrogen bonding inter-
actions has attracted considerable interest in recent years.2,3
Hydrogen bonds, however, represent a fairly weak interaction
and generally result in low association constants. Consequently,
only a small fraction of the donors and acceptors remain
associated, while the remaining molecules are free to diffuse in
solution, especially at low concentrations. This problem can be
alleviated by using multiple hydrogen-bonded arrays designed
to gain strength and directionality.4 The 2-ureido-4[1H]-
pyrimidinone (UP) quadruple hydrogen-bonding unit, for
example, dimerises in a self-complementary array of four
cooperative hydrogen bonds and provides association constants
in excess of 107 MϪ1 in organic solvents.5 Utilizing these high
association constants it is possible to construct supramolecular
polymers.6 Recently the UP unit has been utilized to create
hydrogen-bonded donor–acceptor dyads7 based on photo-
and redox-active oligo(p-phenylenevinylene) (OPV)8 and
[60]fullerene (C60)9 derivatives. Photovoltaic cells based on
supramolecular OPV polymers have demonstrated that the
hydrogen bonds of the UP unit can be incorporated into
working opto-electronic devices.10
Perylene-diimides have been extensively studied as organic
semiconductors in electronic and optical applications such as
field-effect transistors,11 fluorescent solar collectors,12 electro-
photographic devices,13 photovoltaic devices,14 dye lasers,15 and
molecular switches.16 These perylene-diimides have outstanding
chemical, thermal and photochemical stability.17 We recently
reported on photoinduced electron transfer in liquid crystalline
oligo(p-phenylenevinylene)–perylene-diimide–oligo(p-phenyl-
enevinylene) (OPV-PERY-OPV) arrays and in π-stacks of triple
hydrogen-bonded OPV–PERY–OPV trimers.18,19 Here we
extend these studies and describe the synthesis of a perylene-
diimide with the donor–donor–acceptor–acceptor (DDAA)
four-point hydrogen bonding motif UP-unit (PERY-UP)
Results and discussion
Synthesis
The preparation of OPV-UP has been described previously.8 The
synthetic route to PERY-UP is shown in Scheme 1. N,N Ј-bis-
(1-ethylpropyl)perylene-3,4:9,10-tetracarboxylic diimide 120
was partially hydrolysed with potassium hydroxide in tert-
butanol to the anhydride imide 2.21,22 Anhydride imide 2
was subsequently reacted with 2,5-di-tert-butylbenzene-1,4-
diamine23 in the presence of zinc acetate in molten imidazole
to afford the asymmetric perylene-diimide 3. PERY-UP was
obtained by reaction of 3 with carboxamide 424 in chloroform.
Keto–enol equilibrium
The UP-unit of OPV-UP and PERY-UP can exist in two
different tautomeric forms.25 Apart from the pyrimidinone
tautomer (keto) with a DDAA motif, the pyrimidinol tautomer
(enol) exists. Both keto and enol forms are self-complementary
with DDAA and DADA motifs, respectively, but cannot
associate with each other. The keto–enol equilibrium depends
on the polarity of the solvent and the nature of the substituent
on the isocytosine moiety. The keto tautomer is known to
have a higher dimerisation constant (K = 6 × 107 MϪ1 in water-
saturated chloroform; 6 × 108 MϪ1 in toluene) than the enol
tautomer (K = ∼105 MϪ1 in chloroform),25,26 as a result of more
favourable secondary interactions.27,28
1H NMR spectroscopy has been used to determine the
relative amounts of the keto and enol tautomers of PERY-UP
in different solvents by comparing the integrated signals of the
N–H protons. For PERY-UP the amount of keto is 80% in
CDCl3, while it decreases to 50% in toluene-d8. These ratios are
>99% (CDCl3) and 90% (toluene-d8) for OPV-UP.7 As a
consequence, not all PERY-UP molecules can bind to OPV-UP
molecules and we assume that in a 1 : 1 mixture of PERY-UP
and OPV-UP, both homodimers and the heterodimer are
simultaneously present.
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 9 8 – 2 0 3
T h i s j o u r n a l i s © T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 3
198

View Article Online
Fig. 1 Heterodimer of PERY-UP and OPV-UP bound by quadruple hydrogen bonds.
Fig. 2 Absorption (a) and emission (b) spectra of PERY-UP (——),
OPV-UP (---) and a 1 : 1 mixture of PERY-UP and OPV-UP (ؒ ؒ ؒ) in
toluene solution. The excitation wavelength is 527 nm for PERY-UP
and 410 nm for OPV-UP and the mixture.
state of PERY-UP (E(S1) = 2.32 eV). Fluorescence lifetimes (τ)
for OPV-UP and PERY-UP are 1.23 and 3.61 ns, respectively,
as determined from time-correlated single photon counting
(TCSPC) with excitation at 400 nm. The absorption spectrum
of the mixture closely resembles the superposition of the
spectra of the two compounds and gives no evidence of a
significant electronic interaction. In dichloromethane, the
oxidation potential of OPV-UP is Eox = 0.71 V vs. SCE and the
first reduction potential of PERY-UP is Ered = Ϫ0.61 V vs. SCE.
Scheme 1 Synthesis of PERY-UP. a) KOH, tert-butanol; b) 2,5-di-
tert-butylbenzene-1,4-diamine, imidazole, Zn(OAc)2, 160 ЊC, 3.5 h; c)
CHCl3, reflux, 18 h.
Optical properties
Fluorescence quenching
The absorption and photoluminescence spectra of PERY-UP,
OPV-UP and a 1 : 1 mixture of the two compounds in toluene
are shown in Fig. 2. The characteristic absorption peaks of the
perylene-diimide are at 459 nm, 490 nm and 527 nm for PERY-
UP. The absorption spectrum of OPV-UP is not structured and
maximizes at 432 nm. Both compounds fluoresce in toluene
solution with very high quantum yields.7,20 The fluorescence
spectra reveal that the singlet-excited state (S1) of OPV-UP
(E(S1) = 2.52 eV) is higher in energy than the singlet-excited
Fluorescence quenching has been used to study the steady-state
photophysics of OPV-UP–PERY-UP heterodimers. As a result
of the ordering of the singlet states and the difference between
oxidation and reduction potentials, the singlet-excited state
of OPV-UP can act as a donor towards PERY-UP in both
photoinduced energy and photoinduced electron transfer
reactions. Both processes are expected to quench the OPV-UP
fluorescence, when their rate is competitive with the intrinsic
decay of OPV-UP.
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 9 8 – 2 0 3
199

View Article Online
The OPV-UP fluorescence quenching was studied by adding
a mixture of 2 × 10Ϫ5 M PERY-UP and 10Ϫ6 M OPV-UP in
small aliquots to a solution of 10Ϫ6 M OPV-UP in toluene.
Almost selective excitation of OPV-UP in the mixtures was
achieved by irradiation at 410 nm and the fluorescence signal at
493 nm (OPV-UP fluorescence only) was followed as a function
of the PERY-UP concentration in the mixture. A significant
quenching of the OPV-UP fluorescence was observed. The
quenching factor Q, i.e. the ratio of initial OPV-UP
fluorescence (I0) and that of the mixture (I ) is plotted in Fig. 3
Fig. 4 Differential transmission dynamics of the OPV (Sn
S1)
absorption at 900 nm as a function of the pump-probe time delay after
photoexcitation at 450 nm. The concentration PERY-UP is 2 × 10Ϫ4 M
and the concentration OPV-UP is 4 × 10Ϫ5 M in toluene. Solid lines are
fits to decays with time constants of 5 ps and 1100 ps.
induced absorption of the OPV chromophore is present.31 The
dynamics in the low picosecond time range (Fig. 4, ᭺) show a
rapid decay which can be fitted to a mono-exponential decay
with a time constant of 5.1 ps, i.e. a rate of k = 1.9 × 1011 Ϫ1. On
s
longer time scales (Fig. 4, ᭹) a much slower decay is visible with
a mono-exponential time constant of 1.1 ns. The two different
decay times account for the fact that under these conditions
both OPV-UP–PERY-UP heterodimers and OPV-UP–OPV-
UP homodimers are present. It is important to note that a
Fig. 3 Stern–Volmer plot of OPV fluorescence quenching by PERY
derivatives in toluene solution. Curves are shown for OPV-UP ϩ
PERY-UP (᭿); OPV-UP ϩ 1 (᭺); and OPV4 ϩ PERY-UP (ꢀ). The
OPV chromophore concentration is 10Ϫ6 M in each experiment and the
excitation wavelength 410 nm. The detection wavelength is 493 nm for
OPV-UP and 500 nm for OPV4.
control experiment confirmed that the Sn
S1 photoinduced
absorption of the PERY chromophore has only a small (∼10%)
contribution to the photoinduced absorption at 900 nm. The
fast (5.1 ps) decay is attributed to the singlet-energy transfer
reaction from OPV-UP(S1) to PERY-UP in the heterodimer,
while the slow (1.1 ns) decay represents the intrinsic relaxation
of OPV-UP(S1) in the homodimer. The lifetime of the latter
process is close to the photoluminescence lifetime of 1.23 ns of
OPV-UP homodimers, determined by TCSPC.7
after correction for absorption by PERY-UP.29 The Stern–
Volmer constant, defined as KSV = (Q-1)/[PERY-UP], amounts
to KSV = 5.9 × 105 MϪ1 for concentrations of PERY-UP up to
1.13 × 10Ϫ6 M. Two control experiments were performed, in
each experiment one of the two chromophores lacks the
hydrogen bonding UP-group. The first control used 1 instead
of PERY-UP together with OPV-UP and in the second experi-
ment PERY-UP was mixed with a methyl end-capped oligo-
(p-phenylenevinylene) with four phenyl rings (OPV4)30 instead
of OPV-UP. In both cases no fluorescence quenching was
observed (Fig. 3). This indicates that dynamic or collisional
quenching is not important at these low concentrations and
that the quenching can unambiguously be ascribed to the form-
ation of OPV-UP–PERY-UP heterodimers.
Förster energy transfer
The fluorescence quenching studies provide a lower limit for the
rate for singlet-energy transfer via the Stern–Volmer constant
by:
(1)
The origin of the OPV fluorescence quenching in the
OPV-UP–PERY-UP heterodimers can be inferred from the
photoluminescence spectrum (Fig. 2b) of the mixture. When
the 1 : 1 mixture is excited at 410 nm, the fluorescence of the
PERY-UP unit dominates the photoluminescence spectrum
even though the absorption at 410 nm of this chromophore is
negligible. Hence the OPV-UP unit acts as a sensitiser for the
PERY-UP fluorescence. This indicates that a singlet-energy
transfer, rather than electron transfer, occurs in the heterodimer
in toluene in which the photoexcited OPV-UP S1 state evolves
to PERY-UP S1.
using the highest quenching observed in the titration
experiment, Qmax = 6.6, and τ = 1.23 ns, the lower limit for k is
4.5 × 109 sϪ1. Of course, Qmax is limited by the presence of
OPV-UP homodimers and the highest ratio of PERY-UP :
OPV-UP (21.6 : 1) used in the experiment. The actual value, k
= 1.9 × 1011 Ϫ1, determined from the transient spectroscopy, is
s
over 40 times faster.
The Förster equation32 can be used to estimate the distance d
between the centres of the donor and acceptor chromophores
in the energy transfer process.
Transient photoinduced absorption
(2)
Sub-picosecond transient pump-probe spectroscopy (150 fs
pulses) was performed at room temperature on OPV-UP–
PERY-UP solutions to assess the temporal evolution of
the singlet-energy transfer on short timescales. Upon prefer-
ential photoexcitation of the OPV-UP moiety at 450 nm in a
mixture of 4 × 10Ϫ5 M OPV-UP and 2 × 10Ϫ4 M PERY-UP in
toluene, a negative differential transmission was observed by
In eqn. (2), the parameters Nav and n represent Avogadro’s
number and the refractive index of the medium, ꢀ is the
fluorescence quantum yield of the donor in the absence of
transfer, Rc the Förster radius and d is the actual centre-to-
centre distance of the two chromophores involved in the energy
—
probing at 900 nm (Fig. 4). At 900 nm the Sn
S1 photo-
transfer. JF represents the overlap between the absorption (ε(ν))
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 9 8 – 2 0 3
200

View Article Online
Table 1 Change in free energy for charge separation ∆GCS a/eV from
OPV(S1) and PERY(S1), and solvent reorganization energy λs/eV for
OPV-UP–PERY-UP heterodimers in different solvents from eqns (5)
and (7)
(toluene, ε = 2.38; o-dichlorobenzene (odcb), ε = 9.93; benzo-
nitrile, ε = 25.18) the PERY-UP fluorescence signal remained
constant. From this experiment it can be concluded that photo-
induced electron transfer does not occur in the heterodimer
from the PERY-UP S1 state.
OPV
PERY
∆GCS
∆GCS
λs
If electron transfer is absent but thermodynamically feasible,
it is likely to be hampered kinetically. The expression for the
rate constant for non-adiabatic charge separation:
Toluene
odcb
Benzonitrile
Ϫ0.47
Ϫ1.28
Ϫ1.43
Ϫ0.27
Ϫ1.08
Ϫ1.23
0.07
0.79
0.98
a ∆GCSOPV uses E00 = 2.52 eV; ∆GCSPERY uses E00 = 2.32 eV.
(6)
—
of the acceptor (PERY-UP) and the fluorescence (F(ν)) of the
donor (OPV-UP) on an energy scale (cmϪ1) defined as:
shows that kcs is determined by the coupling (V) between donor
and acceptor in the excited state, the reorganization energy λ
and the barrier for charge separation (∆G‡ = (∆Gcs ϩ λ)2/4λ).
cs
(3)
The reorganization energy is the sum of internal (λi) and
solvent (λs) contributions. The latter can be estimated from:35
The factor κ is the so-called orientation factor, which
incorporates the dependence of the energy transfer rate on the
mutual orientation of the transition dipole moments of donor
and acceptor chromophores. It can be expressed as:
(7)
and the results for OPV-UP–PERY-UP are collected in Table 1.
The internal reorganization energy λi is probably not very high
for these extended conjugated systems and is estimated to be in
κ = cos(Θ) Ϫ cos(ꢀ) cos(ꢀ)
(4)
the range of 0.2 to 0.5 eV. Within these limits the barrier ∆G‡
where Θ is the angle between the transition dipole moments
of donor and acceptor and ꢀ (ꢀ) is the angle between the
transition dipole moment of the donor (acceptor) chromo-
phore and the line joining the centres of the two chromophoric
units. In calculating values for κ2, we have assumed that
rotation around the bond joining the UP unit and the
methylene group connecting the UP and the OPV moieties is
possible. For various conformations we find values for κ2
ranging from 2.5 to 3.5. Using the following numbers for the
cs
for charge separation from PERY-UP(S1) remains less than
0.01 eV in odcb and benzonitrile, and is only slightly higher in
toluene (<0.04 eV). The absence of electron transfer in each of
these solvents is therefore ascribed to a very weak electronic
coupling V of donor and acceptor in the excited state, rather
than a high barrier. V is known to be exponentially dependent
on the distance between donor and acceptor. Molecular model-
ling and the value derived from the Förster equation, indicate
an appreciable distance between OPV-UP and PERY-UP units
in the heterodimer, causing a low V. In agreement with this
proposition, a photoinduced electron transfer reaction does
occur between OPV and PERY chromophores in systems were
the two redox-active chromophores are at a much shorter
distance.18,19
OPV-UP–PERY-UP combination, JF = 1.55 × 10Ϫ13 cm6 molϪ1
kEN = 1.9 × 1011 Ϫ1, τ = 1.23 ns, ꢀ = 0.84,7 κ2 = 3, we obtain using
,
s
eqns. (2) and (3): Rc = 64 Å and d = 26 Å. The latter value is
slightly less than the centre-to-centre distance estimated from
molecular modelling (∼33 Å). The difference can be rational-
ized by considering that the singlet-excited states delocalise and
effectively reduce the centre-to-centre distance. A similar result
has been found for energy transfer reactions in covalent
OPV4-C60 donor–acceptor systems.31
Conclusion
Photoluminescence studies reveal that a singlet-energy transfer
reaction occurs in quadruple hydrogen-bonded OPV-UP–
PERY-UP heterodimers (Fig. 1) after excitation of the OPV
chromophore. As a result of the high association constant of
the quadruple hydrogen bond, significant amounts of hetero-
dimers and homodimers are present, even in dilute solutions.
This feature enabled us to follow the temporal evolution of the
singlet-energy transfer reaction using sub-picosecond transient
absorption spectroscopy in the heterodimers on short time-
scales. The time constant of 5.1 ps was obtained for this reac-
tion is in fair agreement with Förster theory. The singlet-excited
in OPV-UP homodimers, is much longer lived and decays with
a time constant of 1.1 ns. Although exergonic, electron transfer
does not occur after photoexcitation as a result of a too weak
electronic coupling between OPV and PERY chromophores in
the excited state. To achieve photoinduced electron transfer in
quadruple hydrogen-bonded systems based on the UP unit a
judicious design of the relative positioning of donor and
acceptor will be required.
Electron transfer
Why does singlet-energy transfer occur from the OPV-UP sing-
let state rather than electron transfer and is electron transfer
possibly subsequent to energy transfer from the singlet-excited
state of PERY-UP? To address these questions it is instructive
to consider the change in free energy for charge separation
using the Weller equation:33,34
(5)
Table 1 shows that according to eqn. (5) photoinduced elec-
tron transfer is energetically possible for the OPV-UP–PERY-
UP heterodimer in solvents of varying polarity from either the
OPV-UP or the PERY-UP singlet-excited states.
To investigate the possibility for electron transfer in the
heterodimer in more detail, the fluorescence signal of PERY-
UP at 578 nm was monitored after selective photoexcitation of
PERY-UP at 527 nm as a function of an increasing amount of
OPV-UP. For this purpose, a solution of 2 × 10Ϫ5 M OPV-UP
and 10Ϫ6 M PERY-UP was added in steps to a 10Ϫ6 M solution
of PERY-UP. Irrespective of the polarity of the solvent
Experimental
General methods
1H NMR and 13C NMR spectra were recorded at room temper-
ature on a Varian Gemini 300 MHz or a Varian Mercury 400
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 9 8 – 2 0 3
201

View Article Online
MHz spectrometer. Chemical shifts are given in ppm (δ) relative
to tetramethylsilane. Matrix assisted laser desorption ionisation
time of flight (MALDI-TOF) mass spectrometry was conducted
on a Perseptive Biosystems Voyager DE-Pro MALDI-TOF
mass spectrometer. UV/Vis absorption spectra were recorded
on a Perkin Elmer Lambda 900 spectrophotometer. Fluor-
escence spectra were recorded on an Edinburgh Instruments
FS920 double-monochromator spectrometer and a Peltier-
cooled red-sensitive photomultiplier. Fluorescence lifetimes
were determined using an Edinburgh Instruments LifeSpec-PS
spectrometer, equipped with a 400 nm picosecond laser (Pico-
Quant PDL 800B) operated at 2.5 MHz and a Peltier-cooled
Hamamatsu micro-channel plate photomultiplier (R3809U-
50). Cyclic voltammograms were measured in 0.1 M tetrabutyl-
ammonium hexafluorophosphate (TBAPF6) as a supporting
electrolyte in dichloromethane using a Potentioscan Wenking
POS73 potentiostat. The working electrode was a Pt disk (0.2
cm2), the counter electrode was a Pt plate (0.5 cm2), and a
saturated calomel electrode (SCE) was used as the reference
electrode, calibrated against Fc/Fcϩ (ϩ0.43 V).
and
N-[6-(1-ethylpentyl)-4-oxo-1,4-dihydropyrimidin-2-yl]-
imidazolyl-1-carboxamide 4 (about 0.02 g, 0.07 mmol) were
refluxed in dry chloroform (dried over molecular sieves) for 18 h
under argon. After cooling to room temperature the reaction
mixture was washed with 1M HCl (5 ml), saturated aqueous
NaHCO3, water, brine and was dried over Na2SO4. The product
was triturated with acetone to yield 0.020 g (54%) of a red solid.
1H NMR (CDCl3)δ two tautomers: 13.27 (s, 1H), 12.59 (s, 1H),
11.67 (s, 1H), minor 11.49 (s), 8.77 (d, 2H, J = 8.06 Hz), 8.69
(d, 2H, J = 8.06 Hz), 8.67 (d, 2H, J = 8.06 Hz), 8.66 (d, 2H, J =
8.06 Hz), minor 7.63 (s), 7.47 (s, 1H), 7.10 (s, 1H), minor 6.27
(s), 5.89 (s, 1H), 5.08 (m, 1H), minor 2.53 (br s), 2.45–2.10
(m, 3H), 1.98 (m, 2H), 1.80–1.50 (m, 4H), 1.44 (s, 9H), 1.30
(s, 13H), 1.00–0.80 (m, 12H). 13C NMR (CDCl3) δ two tauto-
mers: 164.50, 156.06, 155.13, 145.53, 135.22, 134.61, 132.12,
130.07, 129.73, 126.94, 126.60, 123.69, 123.43, 123.27, 57.88,
45.43, 32.88, 31.68, 31.02, 29.41, 26.73, 25.15, 22.65, 14.03,
11.83, 11.57. MALDI-TOF MS (MW = 898.44). Found: m/z =
898.43 [MϪ].
Pump-probe spectroscopy
N-(1-ethylpropyl)perylene-3,4:9,10-tetracarboxylic 3,4-
The femtosecond laser system used for pump-probe experi-
ments consists of an amplified Ti-sapphire laser (Spectra
Physics Hurricane), providing 150 fs pulses at 800 nm with an
energy of 750 µJ at 1 kHz. Pump (450 nm, fluence 0.5 µJ/mm2)
and probe (900 nm) pulses were created by optical parametric
amplification followed by frequency quadrupling or doubling
using two OPA’s (Spectra Physics OPA-C). The pump beam
was linearly polarized at the magic angle (54.7Њ) with respect to
the probe beam. The temporal evolution was recorded using a
Si detector and standard lock-in detection at 500 Hz.
anhydride 9,10-imide (2)
A mixture of N,N Ј-bis(1-ethylpropyl)perylene-3,4:9,10-tetra-
carboxylic diimide 1 (2.87 g, 5.4 mmol), potassium hydroxide
(0.91 g, 0.016 mol) in tert-butanol (100 ml) was heated at 100 ЊC
for 30 min. The reaction mixture was then poured into 400 ml
of 10% HCl and the precipitate was filtered. The residue was
stirred in 200 ml of a warm aqueous solution containing
potassium hydroxide (20 g, 0.36 mol) and potassium chloride
(16 g, 0.21 mol). The solid was filtered and subsequently washed
with the aqueous solution until the solution was no longer
coloured yellow–green. The solid was then stirred in water
and subsequently filtered. The dark red coloured filtrate was
precipitated by addition of hydrochloric acid to a final total
percentage of 10% HCl concentration. The precipitate was
filtered, washed with water and dried at 90 ЊC under vacuum
Acknowledgements
We thank A. Rizzuti, H. M. Keizer and M. van Gerwen for
generous gifts of reactants, and A. El-ghayoury for a sample of
OPV-UP. This work was financially supported by the Council
for Chemical Sciences of the Netherlands Organization for
Scientific Research (CW-NWO) and the Eindhoven University
of Technology in the PIONIER program (98400). The research
of SCJM has also been made possible by a fellowship of the
Royal Dutch Academy of Arts and Sciences.
1
to yield 0.50 g (20%) of a black solid. H NMR (CDCl3) δ
8.80–8.60 (m, 8H), 5.07 (m, 1H), 2.35–2.20 (m, 2H), 2.00–1.90
(m, 2H), 0.93 (t, J = 7.5 Hz). 13C NMR (CDCl3) δ 160.15,
136.61, 133.86, 133.76, 131.81, 124.10, 123.35, 123.24, 119.23,
58.03, 57.86, 25.16, 11.50, Electron impact MS: (MW = 461)
m/z = 461.
N-(1-ethylpropyl)-NЈ-(4-amino-2,5-di-tert-butylphenyl)perylene-
3,4:9,10-tetracarboxylic diimide (3)
References
1 J. Deisenhofer and J. R. Norris, The Photosynthetic Reaction Center,
Academic Press, New York, 1993.
A
mixture of N-(1-ethylpropyl)perylene-3,4:9,10-tetracarb-
2 For reviews see: (a) V. Balzani and F. Scandola, Supramolecular
Photochemistry, Ellis Horwood, Chichester, 1991; (b) J. L. Sessler,
B. Wang, S. L. Springs and C. T. Brown, in Comprehensive
Supramolecular Chemistry, ed. J. L. Atwood, J. E. D. Davies,
D. D. MacNicol, F. Vögtle and Y. Murakami, Pergamon, Oxford,
1996, vol. 4, p. 311; (c) M. D. Ward, Chem. Soc. Rev., 1997, 26, 365;
(d ) P. Piotrowiak, Chem. Soc. Rev., 1999, 28, 143; (e) C. J. Chang,
J. D. Brown, M. C. Y. Chang, E. A. Baker and D. G. Nocera, in
Electron Transfer in Chemistry, ed. V. Balzani, Wiley-VCH,
Weinheim, 2001, vol. 3, 409; ( f ) M. D. Ward, C. M. White,
F. Barigelletti, N. Amaroli, G. Calogero and L. Flamigni, Coord.
Chem. Rev., 1998, 171, 481.
3 (a) P. Tecilla, R. P. Dixon, G. Slobodkin, D. S. Alavi, D. H. Waldeck
and A. D. Hamilton, J. Am. Chem. Soc., 1990, 112, 9408; (b)
A. Harriman, D. J. Magda and J. L. Sessler, J. Phys. Chem., 1991, 95,
1530; (c) A. Harriman, Y. Kubo and J. L. Sessler, J. Am. Chem. Soc.,
1992, 114, 388; (d ) C. Turro, C. K. Chang, G. E. Leroi, R. I. Cukier
and D. G. Nocera, J. Am. Chem. Soc., 1992, 114, 4013; (e)
J. L. Sessler, B. Wang and A. Harriman, J. Am. Chem. Soc., 1993,
115, 10418; ( f ) J. L. Sessler, B. Wang and A. Harriman, J. Am.
Chem. Soc., 1995, 117, 704; (g) P. J. F. de Rege, S. A. Williams and
M. J. Therien, Science, 1995, 269, 1409; (h) J. A. Roberts, J. P. Kirby
and D. G. Nocera, J. Am. Chem. Soc., 1995, 117, 8051; (i) J. P. Kirby,
J. A. Roberts and D. G. Nocera, J. Am. Chem. Soc., 1997, 119, 9230;
(j) E. Prasad and K. R. Gopidas, J. Am. Chem. Soc., 2000, 122,
3191; (k) A. J. Myles and N. R. Branda, J. Am. Chem. Soc., 2001,
oxylic 3,4-anhydride 9,10-imide 2 (0.048 g, 0.10 mmol), 2,5-di-
tert-butylbenzene-1,4-diamine (0.14 g, 0.64 mmol), imidazole
(2.5 g) and a few grains of zinc acetate were stirred at 160 ЊC for
3.5 h under argon. After cooling to room temperature the
reaction mixture was purified extensively by column chromato-
graphy (SiO2, CH2Cl2–ethanol 95 : 5, CH2Cl2–methanol 99 :
1–97.5 : 2.5, ethyl acetate–n-hexane 4 : 1 and ethyl acetate–n-
hexane 3 : 2). After washing the solid with n-hexane 0.046 g
(67%) of 3 was obtained pure as a red solid. 1H NMR (CDCl3) δ
8.80–8.65 (m, 8H), 6.87 (s, 1H), 6.82 (s, 1H), 5.08 (m, 1H), 3.93
(s, 2H), 2.40–2.20 (m, 2H), 2.10–1.90 (m, 2H), 1.54 (s, 18H),
0.94 (t, 6H, J = 7.3 Hz). 13C NMR (CDCl3) δ 164.88, 145.24,
145.07, 135.08, 134.71, 133.07, 131.99, 130.05, 129.79, 129.40,
126.96, 126.66, 124.02, 123.73, 123.31, 123.24, 118.18, 100.34,
57.92, 34.04, 31.76, 29.73, 25.21, 11.51. MALDI-TOF MS
(MW = 663.31) m/z = 663.02 [MϪ].
N-(1-ethylpropyl)-NЈ-{4-[2-ureido-6-(1-ethylpentyl)-4[1H]-
pyrimidinone]-2Ј,5Ј-di-tert-butylphenyl}perylene-3,4:9,10-tetra-
carboxylic diimide (PERY-UP)
N-(1-ethylpropyl)-NЈ-(4-amino-2,5-di-tert-butylphenyl)peryl-
ene-3,4:9,10-tetracarboxylic diimide (3): (0.0262 g, 0.04 mmol)
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 9 8 – 2 0 3
202

View Article Online
123, 177; (l ) M. A. Smitha, E. Prasad and K. R. Gopidas, J. Am.
Chem. Soc., 2001, 123, 1159; (m) J. L. Sessler, M. Sathiosatham,
C. T. Brown, T. A. Rhodes and G. Wiederrecht, J. Am. Chem. Soc.,
2001, 123, 3655; (n) M. A. Smitha and K. R. Gopidas, Chem. Phys.
Lett., 2001, 350, 86.
4 For a recent review see: D. C. Sherrington and K. A. Taskinen,
Chem. Soc. Rev., 2001, 30, 83.
5 R. P. Sijbesma, F. H. Beijer, L. Brunsveld, B. J. B. Folmer,
J. H. K. K. Hirschberg, R. F. M. Lange, J. K. L. Lowe and
E. W. Meijer, Science, 1997, 278, 1601.
6 L. Brunsveld, B. J. B. Folmer, E. W. Meijer and R. P. Sijbesma,
Chem. Rev., 2001, 101, 4071.
7 E. H. A. Beckers, P. A. van Hal, A. P. H. J. Schenning,
A. El-ghayoury, E. Peeters, M. T. Rispens, J. C. Hummelen,
E. W. Meijer and R. A. J. Janssen, J. Mater. Chem., 2002, 12, 2054.
8 A. El-ghayoury, E. Peeters, A. P. H. J. Schenning and E. W. Meijer,
Chem. Commun., 2000, 1969.
18 E. Peeters, P. A. van Hal, S. C. J. Meskers, R. A. J. Janssen and E. W.
Meijer, Chem. Eur. J., 2002, 8, 4470.
19 A. P. H. J. Schenning, J. van Herrikhuyzen, P. Jonkheijm, Z. Chen,
F. Würthner and E. W. Meijer, J. Am. Chem. Soc., 2002, 124,
10252.
20 S. Demmig and H. Langhals, Chem. Ber., 1988, 121, 225.
21 H. Kaiser, J. Lindner and H. Langhals, Chem. Ber., 1991, 124, 529.
22 Y. Nagao, T. Naito, Y. Abe and T. Misono, Dyes Pigm., 1996, 32,
71.
23 F. Bell, J. Chem. Soc., 1958, 120.
24 H. M. Keizer, to be published.
25 F. H. Beijer, R. P. Sijbesma, H. Kooijman, A. L. Spek and
E. W. Meijer, J. Am. Chem. Soc., 1998, 120, 6761.
26 S. H. M. Söntjens, R. P. Sijbesma, M. H. P. van Genderen and
E. W. Meijer, J. Am. Chem. Soc., 2000, 122, 7487.
27 W. L. Jorgensen and J. Pranata, J. Am. Chem. Soc., 1990, 112,
2008.
9 (a) M. T. Rispens, L. Sánchez, J. Knol and J. C. Hummelen, Chem.
Commun., 2001, 161; (b) J. J. González, S. González, E. María
Priego, C. Luo, D. M. Guldi, J. de Mendoza and N. Martín,
Chem. Commun., 2001, 163; (c) L. Sánchez, M. T. Rispens and
J. C. Hummelen, Angew. Chem., Int. Ed., 2002, 41, 838.
10 A. El-ghayoury, A. P. H. J. Schenning, P. A. van Hal, J. K. J. van
Duren, R. A. J. Janssen and E. W. Meijer, Angew. Chem., Int. Ed.,
2001, 40, 3660.
28 J. Pranata, S. G. Wierschke and W. L. Jorgensen, J. Am. Chem. Soc.,
1991, 113, 2810.
29 The data points are corrected for the simultaneous excitation of the
PERY-UP at 410 nm and for the re-absorption of the OPV-UP
emission by PERY-UP at 493 nm (especially important at high
excess of PERY-UP).
30 E. Peeters, A. Marcos, S. C. J. Meskers and R. A. J. Janssen, J. Chem.
Phys., 2000, 112, 9445.
31 P. A. van Hal, R. A. J. Janssen, G. Lanzani, G. Cerullo, M. Zavelani-
Rossi and S. De Silvestri, Phys. Rev. B, 2001, 64, 075206.
32 T. Förster, Discuss. Faraday Soc., 1959, 27, 7.
11 P. R. L. Malenfant, C. D. Dimitrakopoulos, J. D. Gelorme,
L. L. Kosbar, T. O. Graham, A. Curioni and W. Andreoni, Appl.
Phys. Lett., 2002, 80, 2517.
12 G. Seybold and G. Wagenblast, Dyes Pigm., 1989, 11, 303.
13 K. Y. Law, Chem. Rev., 1993, 93, 449.
33 A. Weller, Z. Phys. Chem. Neue Folge, 1982, 133, 93.
34 In eqn. (5), Ϫe is the electron charge, ε0 the vacuum permittivity, εs
the polarity of the solvent, εref the polarity of the solvent used to
determine the redox potentials Eox(D) and Ered(A), Rcc the centre-to-
centre distance of positive and negative charges and rϩ and rϪ the
radii of the positive and negative ions. E00 is the energy of the excited
state from which electron transfer occurs. For OPV-UP, rϩ = 5.05 Å
(Ref. 31). For the perylene diimide segment of PERY-UP, rϪ = 4.71
Å was taken from the density (ρ = 1.59 g cmϪ1) of N,N Ј-
dimethylperylene-3,4:9,10-tertacarboxylic diimide derived from the
X-ray crystallographic data (E. Hädicke and F. Graser, Acta Cryst.
14 (a) D. Wohrle and D. Meissner, Adv. Mater., 1991, 3, 129; (b)
D. Schlettwein, D. Wohrle, E. Karmann and U. Melville, Chem.
Mater., 1994, 6, 3; (c) S. Ferrere, A. Zaban and B. A. Gregg, J. Phys.
Chem. B, 1997, 101, 4490; (d ) L. Schmidt-Mende, A. Fechtenkötter,
K. Müllen, E. Moons, R. H. Friend and J. D. MacKenzie, Science,
2001, 293, 1119.
15 M. Sadari, L. Hadel, R. R. Sauers, S. Husain, K. Krogh-Jespersen,
J. D. Westbrook and G. R. Bird, J. Phys. Chem., 1992, 96, 7988.
16 M. P. O’Neil, M. P. Niemczyk, W. A. Svec, D. Gosztola,
G. L. Gaines and M. R. Wasielewski, Science, 1992, 257, 63.
17 W. A. Fisher, in Pigment Handbook Volume I: Properties and
Economics; ed. T. C. Patton, John-Wiley & Sons, New York, 1973,
p 667.
1
–
C, 1986, 42, 189) via rϪ = [3M/(4πρNA)] . Rcc was set to 33 Å.
3
35 H. Oevering, M. N. Paddon-Row, M. Heppener, A. M. Oliver,
E. Cotsaris, J. W. Verhoeven and N. S. Hush, J. Am. Chem. Soc.,
1987, 109, 3258.
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 9 8 – 2 0 3
203