Porphyrin, phthalocyanine and porphyrazine derivatives with multifluorenyl substituents as efficient deep-red emitters

Article abstract of DOI:10.1002/chem.200700054

The synthesis and photophysical properties are described for a series of porphyrin, phthalocyanine and pyrazinoporphyrazine derivatives which bear four or eight peripheral fluorenyl substituents as antennae. Representative examples are 5,10,15,20-tetra(9,9-dihexyl-9H-fluoren-2-yl)porphyrin (2), 5,10,15,20-tetrakis[4-(9,9-dihexyl-9H-fluoren-2-yl)phenyl]porphyrin (3), 2,3,9,10,16,17,23,24-octakis(9,9-dihexyl-9H-fluoren-2-yl)-29H, 31H-phthalocyanine (8) and 2,3,9,10,16,17,-23,24-octakis[4-(9,9-dihexyl-9tf- fluoren-2-yl)phenyl]-29H31H-tetrapyrazinoporphyrazine (9). Palladiummediated Suzuki-Miyaura cross-coupling reactions have been key steps for attaching the substituents. The compounds are deep-red emitters: λ_max(em) = 659 (3), 737 (8) and 684 nm (9). Their absorption and emission spectra, their fluorescence lifetimes and quantum yields are correlated with the structures of the macrocycles and the substituents. The solution fluorescence quantum yields of porphyrin derivatives substituted with fluorene (2-4) and terphenyl substituents (7) (Φ_f = 0.21-0.23) are approximately twice that of tetraphenylporphyrin. For phthalocyanine derivative 8, Φ_f was very high (0.88). Specific excitation of the fluorene units of 8 produced emission from both of them (λ_max = 480nm) and also from the phthalocyanine core (λ_max = 750 nm), indicating a competitive rate of energy transfer and radiative decay of the fluorenes. Organic light-emitting devices (OLEDs) were made by spincoating techniques by using a polyspirobifluorene (PSBF) copolymer as the host blended with 3 (5 wt. % ) in the configuration ITO/PEDOT:PSS/PSBF copolymer:3/Ca/Al. Deep-red emission (λ_max= 663nm; CIE coordinates x = 0.70, y = 0.27) was observed with an external quantum efficiency of 2.5 % (photons/electron) (at 7.5 mA cm^-2), a low turn-on voltage and high emission intensity (luminance) of 5500 cdm^-2 (at 250 mA/m^-2).

Full text of DOI:10.1002/chem.200700054

DOI: 10.1002/chem.200700054
Porphyrin, Phthalocyanine and Porphyrazine Derivatives with Multifluorenyl
Substituents as Efficient Deep-Red Emitters
Carl A. Barker, Xianshun Zeng, Sylvia Bettington, Andrei S. Batsanov,
[
a]
Martin R. Bryce,* and AndrewBeeby
Abstract: The synthesis and photophys-
ical properties are described for a
series of porphyrin, phthalocyanine and
lmax(em)=659 (3), 737 (8) and 684 nm
(9).Their absorption and emission
spectra, their fluorescence lifetimes
and quantum yields are correlated with
the structures of the macrocycles and
the substituents.The solution fluores-
cence quantum yields of porphyrin de-
rivatives substituted with fluorene (2–
from the phthalocyanine core (lmax =
750 nm), indicating a competitive rate
of energy transfer and radiative decay
pyrazinoporphyrazine
derivatives
of the fluorenes.Organic light-emitting
A
H
E
G
which bear four or eight peripheral flu-
orenyl substituents as antennae.Repre-
sentative examples are 5,10,15,20-
tetra(9,9-dihexyl-9H-fluoren-2-yl)por-
phyrin (2), 5,10,15,20-tetrakis[4-(9,9-di-
hexyl-9H-fluoren-2-yl)phenyl]porphy-
devices (OLEDs) were made by spin-
coating techniques by using a poly-
spirobifluorene (PSBF) copolymer as
the host blended with 3 (5 wt.%) in
the configuration ITO/PEDOT:PSS/
PSBF copolymer:3/Ca/Al.Deep-red
emission (lmax =663 nm; CIE coordi-
nates x=0.70, y=0.27) was observed
with an external quantum efficiency of
4) and terphenyl substituents (7) (F =
f
0.21–0.23) are approximately twice that
of tetraphenylporphyrin.For phthalo-
A
C
H
T
R
E
U
N
G
rin (3), 2,3,9,10,16,17,23,24-octakis(9,9-
dihexyl-9H-fluoren-2-yl)-29H,31H-
phthalocyanine (8) and 2,3,9,10,16,17,-
cyanine derivative 8, F was very high
f
(0.88). Specific excitation of the fluo-
rene units of 8 produced emission from
both of them (lmax =480 nm) and also
A
C
H
T
R
E
U
N
G
23,24-octakis[4-(9,9-dihexyl-9H-fluo-
ren-2-yl)phenyl]-29H,31H-tetra-
pyrazinoporphyrazine (9).Palladium-
2.5%
(photons/electron)
(at
À2
7.5 mAcm ), a low turn-on voltage
and high emission intensity (lumi-
nance) of 5500 cdm (at 250 mA/m ).
A
C
H
T
R
E
U
N
G
A
C
H
T
R
E
U
N
G
ACHTREUNG
À2
2
mediated Suzuki–Miyaura cross-cou-
pling reactions have been key steps for
attaching the substituents.The com-
Keywords: fluorene · fluorescence ·
phthalocyanines · porphyrazine ·
porphyrinoids
pounds
are
deep-red
emitters:
Introduction
rocycles, for example, porpyrazines (tetraazaporphyrins),
has ensured that there is continued interest in the synthesis
of new functionalised derivatives which are of academic and
industrial importance.These macrocycles exhibit high chem-
ical and thermal stability, and their well-defined optical ab-
sorption and emission properties have led to many applica-
tions in materials science.For example, tetraphenylporphyr-
in is a red emitter with reasonable fluorescence efficiency
The array of optoelectronic and coordination properties dis-
[
1]
[2]
played by porphyrins, phthalocyanines and related mac-
[
a] Dr.C.A.Barker, Dr.X.Zeng, Dr.S.Bettington, Dr.A.S.Batsanov,
Prof.M.R.Bryce, Dr.A.Beeby
Department of Chemistry, Durham University
Durham DH1 3 LE (UK)
Fax : (+44)191-384-4737
E-mail: m.r.bryce@durham.ac.uk
[3]
(
F =0.11) which has been used as a dopant in a host poly-
f
fluorene matrix to give red organic light-emitting devices
[
4]
(
OLEDs). The narrow emission linewidth of porphyrins
[5]
makes them attractive materials in this regard.Porphyrin
[6]
Supporting information for this article contains experimental details
and characterisation data for 4–7, 11, 13 and 17–19, general experi-
mental details for photophysical and OLED measurements, the exci-
tation/emission matrix for compound 8, the X-ray molecular structure
of 18 and calculated minimum-energy conformations for 3 and 8.This
information is available on the WWW under
and phthalocyanine derivatives with peripheral substitu-
ents have been used as probes of intramolecular charge-
transport phenomena (through-bond and/or through-space)
which can modulate fluorescence of the macrocycle.Many
of the properties of these macrocycles are highly dependent
on the extent of intermolecular p–p stacking interactions,
http://www.chemeurj.org/ or from the author.
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Chem. Eur. J. 2007, 13, 6710 – 6717

FULL PAPER
with strong interactions between neighbours (for example,
face-to-face dimerisation), leading to fluorescence quench-
ing.Bulky peripheral substituents can reduce self-quenching
and enhance fluorescence intensity.In a complementary ap-
proach, axial substituents on a metallophthalocyanine (for
example, attached to the central Si atom) can similarly
reduce intermolecular stacking.For these systems, intramo-
lecular interactions between the axial substituents and the
ACHTREUNG
To explore the effect of changing the macrocyclic core
while retaining peripheral fluorenyl substituents, the phtha-
locyanine
(Schemes 4 and 5, respectively) and 9 were synthesized by
tetramerisation of the precursor dinitrile derivatives 17 and
19, respectively.The model porphyrazine 10 was obtained
from 5,6-di-p-tolylpyrazine-2,3-dicarbonitrile following liter-
and
pyrazinoporphyrazine
derivatives
8
[7]
macrocyclic p-system can be examined.
[19]
The aim of the present work was to synthesize a series of
porphyrin, phthalocyanine and pyrazinoporphyrazine deriv-
atives functionalised with peripheral 9,9-dialkylfluorenyl
substituents and to explore the energy transfer between the
fluorenyl units and the macrocyclic core.Fluorene was
chosen as a substituent for this study as it is a thermally
very stable unit which can act as an antenna to harvest and
transfer energy efficiently to longer wavelength emitters in
ature procedures.
Optimised geometries: The calculated optimised geometries
(Hyperchem V6.03) for porphyrin derivative 3 and pyr-
A
H
R
U
G
respectively.For structure 3, the phenyl substituents are sub-
stantially twisted out of the plane of the porphyrin ring
system, as observed in crystal structures of other 5,10,15,20-
tetraphenylporphyrin derivatives.
core is essentially planar; the calculated torsion angles for
the diphenylpyrazine subunits in 8 were very similar
[8]
[20]
blends or composite structures. Furthermore, we have
shown that small molecules (namely, iridium complexes)
substituted with multifluorene units have good structural
For 8, the macrocyclic
compatibility when used as dopants in a host poly
A
H
R
U
G
A
T
E
N
(Æ<18) to those observed in the X-ray molecular structure
[9]
matrix for OLED applications. The present work has fur-
nished a series of deep-red emitters with good solubility in
organic solvents, high stability and interesting photophysical
properties, including a new porphyrin material for efficient
red OLEDs.Related porphyrin systems reported during the
course of our studies are: an analogue of 3 with octyl chains
of precursor 18 (see the Supporting Information).
Photophysical studies: The photophysical data for com-
pounds 1–10 in dichloromethane solution are collated in
Table 1.The free-base porphyrins 2, 3 and 7 display similar
absorption and emission profiles to the model compound 1.
[
10]
À6
on the fluorene moieties,
four truxene units
a porphyrin substituted with
Dilute solutions were used (10 m) to minimize any tenden-
[11]
and a platinum tetraphenylporphyrin
cy for aggregation.The UV-visible absorption spectra were
characterized by a sharp intense Soret band at lmax =425 nm
approximately, with four weak Q-bands in the range of 500–
660 nm (Figure 3).The Soret bands of 2, 3, 4 and 7 were
slightly red-shifted compared to 1.These compounds all
[12]
derivative with eight peripheral carbazole units. The latter
system was used to obtain saturated red electroluminescence
from a multilayer OLED.
[21]
A
H
R
U
G
Results and Discussion
peaks (lmax =660 and 725 nm approximately), which are
again consistently red-shifted compared to 1 (by 3–4 nm)
due to the conjugated fluorenyl substituents in 2, 3 and 4:
no significant red shift is observed in the less-conjugated ter-
phenyl compound 7.Compared to 2, increasing the conjuga-
tion in the substituents with an additional phenyl group
(derivative 3) has no appreciable effect on the fluorescence
properties.
Synthesis: 5,10,15,20-Tetra-para-tolylporphyrin (1) was syn-
thesised as a known model compound following a standard
from pyrrole and para-tolualdehyde in refluxing
propionic acid.The tetrakis(fluorenyl) derivative 2 was ob-
tained from pyrrole and 9,9-dihexyl-9H-fluorene-2-carbalde-
[13]
route
[14]
hyde (11) in 13% yield under standard Lindsey condensa-
[15]
tion conditions (Scheme 1). The n-hexyl chains at C(9) of
the fluorene units ensured good solubility of the product in
organic solvents.The analogue 3 containing a phenyl spacer
between the porphyrin core and each of the fluorene units
was obtained by using different methodology (Scheme 2).
The efficient four-fold Suzuki–Miyaura cross-coupling of
The fluorescence quantum yield obtained for tetra-para-
tolyl compound 1 (F =0.11) is in agreement with the litera-
f
ture values for 1 and the tetraphenyl analogue (F =0.11–
f
[3,22]
0.13).
The F values for the fluorenyl derivatives 2–4
f
(F =0.21) and the terphenyl derivative 7 (F =0.23) are
f
f
substantially increased compared to compound 1 and are
high for the porphyrin derivatives.The very high literature
[16]
5
,10,15,20-tetrakis(4-bromophenyl)porphyrin (12)
with
[
17]
13
gave 3 in 72% yield.The octakis(N-carbazolyl) deriva-
value for 5,10,15,20-tetra[3,5-di(4-tert-butylphenyl)benzyl]-
A
H
R
U
G
tive 4 was similarly isolated in 52% yield from the corre-
sponding boronate ester reagent 14.The zinc derivatives of
porphyrin (F =0.66 in dichloromethane) can be attributed
f
to reduced aggregation due to the four bulky tert-butyl
[23]
3
and 4 (for example, complexes 5 and 6, respectively) were
groups. The fluorescence lifetime we observed for 1 (t =
f
obtained upon reaction with zinc acetate by using standard
8.6 ns) is similar to the literature value of 9.40 ns obtained
in a different solvent mixture. The substituents in 2–4 and
[18]
[22]
procedures.
taining branched terphenyl substituents was synthesized
14% yield) by the reaction of pyrrole with 3,5-diphenylbenz-
For comparative purposes, analogue 7 con-
7 do not significantly effect the lifetimes (t =7.3–8.4 ns)
f
(
which are long and indicative of a small non-radiative decay
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M.R.Bryce et al.
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Chem. Eur. J. 2007, 13, 6710 – 6717

Porphyrin, Phthalocyanine and Porphyrazine Derivatives
FULL PAPER
Scheme 1.i) Trifluoroacetic acid, CHCl
0 h, NEt (13% yield).DDQ =2,3-dichloro-5,6-dicyano-1,4-benzoquin-
one.
3
, 618C, 3 h; then DDQ, 208C,
1
3
ACHTREUNG
Scheme 5.i) 13, Pd
59% yield); ii) Li, n-C
yield).
A
H
R
U
G
3
)
4
, Na
2 3 2
CO , THF, toluene, H O, 1058C, 72 h
(
H11OH, 1,4-dioxane, 1058C, 12 h, AcOH (23%
Scheme 2.i) Pd
yield); ii) Zn(OAc)
Na CO , THF, toluene, H
28C, 4 h (95% yield).
A
C
H
T
R
E
U
N
G
(PPh
3
)
4
, Na
CHCl
O, 1058C (52% yield); iv) Zn
2
CO
3
, THF, toluene, H
628C, 4 h (95% yield); iii) Pd
(OAc) , CHCl
2
O, 1058C, 24 h (72%
A
C
H
T
R
E
U
N
G
2
,
3
,
A
H
R
U
G
3
)
4
,
,
2
3
2
A
H
R
U
G
2
3
6
constant.A comparison of
3
with 4 and 5 with 6 (Table 1)
shows that the carbazolyl units
of 4 and 6 do not have any sig-
nificant influence on the photo-
physical properties of the free
bases or the zinc complexes.We
had envisaged that the flexible
N-hexyl spacers could enable
some of the electron-rich carb-
Scheme 3.i) Trifluoroacetic
acid, CHCl , 508C, 2 h; then
DDQ, 208C, 2.5 h, NEt (14%
3
3
yield).
Figure 1.Two views of the optimised geometry of porphyrin derivative 3
(
with hydrogens omitted).
Scheme 4.i) Pd
A
C
H
T
R
E
U
N
G
(PPh
3 4 2 3 2
) , Na CO , THF, toluene, H O, 1108C, 96 h (87%
yield); ii) Li, n-C
5
H
11OH, 1258C, 2 h, HCl (11% yield).
The zinc-centred derivatives 5 and 6 display significantly
blue-shifted emission as well as greatly reduced F and tf
f
A
C
H
T
R
E
U
N
G
azolyl units to be oriented in such a way that porphyrin fluo-
values compared to their free-base precursors 3 and 4, re-
rescence might be quenched by intramolecular through-
space transfer.However, this effect is not observed.
spectively.These values are characteristic of zinc porphyrins
[24]
in general
and demonstrate the effective reduction of
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6713

M.R.Bryce et al.
Figure 3.Normalised absorption spectra of porphyrins 1, 2, 3 and 7 in di-
chloromethane at 298 K.
Figure 4.Normalised emission spectra of porphyrins 1, 2, 3, 5 and 7 in di-
chloromethane at 298 K.
Figure 2.Two views of the optimised geometry of pyrazinoporphyrazine
derivative 8 (with hydrogens omitted).
[25]
peripherally substituted free-base phthalocyanines.
The
fluorescence lifetime for 8 (l =615 nm, t =4.8 ns) is con-
ex
f
sistent with values for derivatives bearing peripheral alkoxy
[26]
substituents, demonstrating that t is relatively insensitive
f
Table 1.Solution photophysical data obtained in dichloromethane solu-
tion (10 –10 m).
À4
À7
to the substituents at the periphery of the phthalocyanine
core.
a]
[b]
[b]
Compound
l
max
A
C
H
T
R
E
U
N
G
(abs)
l
max(em)
F [
f
t
f1 [ns]
tf2 [ns]
Excitation of 8 at 300 nm produced a second component
to the fluorescence lifetime, corresponding to an emission at
lem ꢀ500 nm.When excitation spectra were run with moni-
[
nm]
[nm]
1
2
3
4
5
6
7
8
9
420
427
426
427
427
427
424
696, 729
654, 681
669
656 (721)
660.5 (725)
659 (724)
659.5 (725)
603.5 (651)
603 (650.5)
657 (715.5 br) 0.23
737
684
676.5
0.11
0.21
0.21
0.21
0.088 1.6
0.088 1.6
8.6
8.2
8.3
8.4
–
–
–
–
–
–
–
–
toring at both l =500 and 760 nm, it was clear that this
em
emission band was due entirely to the fluorene units.Specif-
ic excitation of the fluorene units produced emission from
them and also from the phthalocyanine core (Figures S5 and
S6 in the Supporting Information).Thus, we conclude that
following excitation, the fluorene units decay by two path-
ways: either by direct luminescence giving rise to the band
at lmax =480 nm, or by energy transfer to the Pc core, lead-
ing to red emission at lmax =750 nm.This indicates that the
rate of energy transfer from the peripheral fluorene groups
to the core is competing with the radiative decay of the fluo-
renes and hence energy transfer is not as rapid as might be
expected for a closely coupled system, which in turn may be
due to the poor spectral overlap between the fluorene emis-
sion and the B1/B2 absorption bands of the Pc.
7.3
4.7
0.88
0.019 4.0 (60%) 1.5 (40%)
0.022 7.0 (75%) 3.6 (25%)
1
0
[
8
1
a] Æ10%;
l
ex =430 nm (615 nm for 8–10),
15 nm for 5–6, 630–850 nm for 8–10), 293 K, in dichloromethane.[b]
0%; for 1–7, Æ0.1 ns, lex =400 nm (635 nm for 8–10), lem =655–700 nm
lem =600–850 nm (525–
Æ
(
600–650 nm for 5–6, 690 nm for 8–10), 293 K, in dichloromethane.
fluorescence from the porphyrin by inter-system crossing to
the excited triplet state.
Phthalocyanine derivative 8 displays an extremely high
fluorescence quantum yield (F =0.88); PLQY values of this
magnitude have been observed in other highly conjugated
The spectra of pyrazinoporphyrazine derivatives 9 and 10
show small Stokes shifts, indicating very little molecular
f
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Chem. Eur. J. 2007, 13, 6710 – 6717

Porphyrin, Phthalocyanine and Porphyrazine Derivatives
FULL PAPER
A
C
H
T
R
E
U
N
G
rearrangement in the excited state, as observed for other oc-
was chosen from among the available derivatives due to its
good processability and the high-quality blend films which
were formed.The structure of the copolymer is shown in
Figure S7 in the Supporting Information.These unoptimised
devices showed significantly improved efficiencies and sta-
[27]
tasubstituted derivatives. The emission maximum for 9 is
red-shifted (by 7.5 nm) compared with 10.For 9, the p–p*
absorption band in the 300–400 nm region originated from
[28]
the peripheral fluorenyl-substituents.
Several excitation
[4]
spectra were run at varying emission wavelengths (Figure 5),
confirming that the majority of energy is absorbed by the
peripheral substituents and then transferred to the macrocy-
clic core.The reason for the low F values for 9 and 10 is
unclear at present.
bility compared to tetraphenylporphyrin devices. A major
factor here is likely to be that the phenyl-fluorenyl units of
3 increase the compatibility of the small-molecule guest
with the polymer host.Hence, a more homogeneous blend
is formed with a reduced tendency for phase segregation
which would lead to a decay of efficiency with increasing
f
[31]
current density. Figure 6 shows the normalised electrolu-
Figure 5.Excitation spectra of 9 in dichloromethane at 298 K.
Figure 6.Normalised thin-film absorbance of the PSBF copolymer host
and electroluminescence spectra of devices ITO/PEDOT:PSS/PSBF co-
polymer/Ba/Al and ITO/PEDOT:PSS/PSBF copolymer:3/Ba/Al (5% by
weight of 3 in the blend).
Both 9 and 10 displayed a large secondary component to
the fluorescence lifetime, which may be the result of elec-
tron transfer within the molecule.The absorption spectrum
of 9 was essentially unchanged after storing a solution in di-
chloromethane in direct sunlight for five days (Figure S4 in
the Supporting Information).Moreover, MALDI-TOF anal-
minescence (EL) spectra of devices containing solely the
PSBF copolymer and the PSBF copolymer device doped
with compound 3.The EL spectrum of the device ( lmax
=
665, 730 nm) is very similar to the solution PL spectrum of 3
(lmax =659, 724 nm).The emission spectrum (CIE coordi-
nates x=0.70, y=0.27) represents a very deep red, as shown
on a colour CIE diagram in Figure S8 in the Supporting In-
formation.
ysis of the solution showed only a single peak due to the
+
[
M] ion with no evidence of decomposition.
OLED studies: Bradley et al.demonstrated energy transfer
from blue to red in an OLED by doping tetraphenylpor-
phyrin into a poly(9,9-dioctylfluorene) host: an external
quantum efficiency (EQE) of 0.9% (photons/electron) and
Figure 7 shows that the blend devices reached an EQE of
À2
2.5% at 7.5 mAcm .The good stability of the EQE at high
current densities is a notable feature of these devices.The
devices had a low turn-on voltage (approximately 3 V) and
recording the EL spectra at 6 V established that the time to
half brightness was approximately 15 h under continuous op-
eration with essentially no change in the spectral profile.
This confirms the high chemical stability of the blend.
Taking these data together with the high emission intensity
À2
[4]
a luminance of 90 cdm
ers
was obtained. Other work-
[
10,11,12]
have noted the potential of functionalised por-
phyrins to serve as emitters in OLEDs.In a complementary
approach, Cao et al.reported saturated red emission from
copolymers comprising 9,9-dioctylfluorene and 4,7-di(4-hex-
ylthieny-2-yl)-2,1,3-benzothiadiazole (DHTBT) units (for
example, units with a wide and narrow HOMO–LUMO gap,
respectively), utilising efficient intramolecular energy trans-
À2
À2
(luminance) of 5500 cdm (at 250 mAm ) (Figure 8) it has
been established that compound 3 is a very promising mate-
rial for OLED applications.Optimisation (with respect to
layer thicknesses, doping concentration, use of encapsulation
procedures, etc.) would be expected to enhance perfor-
mance and durability.
[29]
fer from the former (blue) to the latter (red) units.
We have tested compound 3 in an OLED with the follow-
ing configuration: ITO/PEDOT:PSS/PSBF copolymer:3/Ba/
Al, in which the emissive layer is 3 as a blend (5 weight%)
[30]
in a polyspirobifluorene copolymer host.
Compound 3
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6715

M.R.Bryce et al.
on voltage and emission intensity (luminance) of
À2
À2
5
500 cdm (at 250 mAm ).Future work will address new
functionalisation modes at the periphery of the macrocyclic
platforms to enable further tuning of the structural, optoe-
lectronic and device properties of these interesting multi-
functional materials.
Experimental Section
5
,10,15,20-Tetra(9,9-dihexyl-9H-fluoren-2-yl)porphyrin (2): Trifluoro-
AHCTREUNG
acetic acid (0.31 mL, 4.02 mmol) was added dropwise to a stirred solution
[
14]
of pyrrole (0.19 mL, 2.73 mmol) and 11 (0.13 g, 2.73 mmol) in degassed
anhydrous chloroform (20 mL) and the solution was stirred at 618C for
3
h.After allowing the solution to cool to room temperature, DDQ
(
0.62 g, 2.73 mmol) was added and stirring was then continued for a fur-
ther 10 h. Triethylamine (0.56 mL, 4.02 mmol) was added dropwise and
the reaction mixture was filtered through a short column (initial eluent:
dichloromethane followed by ethyl acetate) giving a crude product after
the removal of solvents in vacuo.Purification by column chromatography
Figure 7.The external quantum efficiency (EQE) versus current density
for the device ITO/PEDOT:PSS/PSBF copolymer:3/Ba/Al (5% by
weight of 3 in the blend).
(
(
(
(
7
eluent: 33% dichloromethane in hexane) gave 2 as a purple solid
1
145 mg, 13%).M p. .276–278 8C; H NMR (300 MHz, CDCl
2H, s; NH), 0.74 (24H, t, J=3.6 Hz), 0.87–0.89 (16H, m), 1.13–1.15
3
): d=À1.50
3
3
48H, m), 2.12–2.14 (16H, m), 7.43–7.50 (12H, m), 7.97 (4H, d, J=
3
3
.2 Hz), 8.08 (4H, d, J=7.8 Hz), 8.22 (8H, d, J=6.6 Hz), 8.92 ppm (8H,
3
13
d, J=13.8 Hz); C NMR (100 MHz, CDCl
3
): d=14.06, 22.76, 24.02,
2
1
2
7
9.99, 31.99, 40.07, 55.95, 118.01, 120.03, 120.09, 123.76, 127.74, 127.88,
29.54, 141.43, 141.95, 149.26, 151.97 ppm; IR (Nujol): 3304, 3176, 2949,
918, 2852, 2719, 2663, 1463, 1377, 1299, 1257, 1146, 1054, 1018, 965, 874,
À1
+
99, 720 cm ; MS (MALDI-TOF): m/z: 1639.7 [M] ; elemental analysis:
calcd (%) for C120
H 8.74, N 3.09.
142 4 2
H N ·H O: C 86.91, H 8.75, N 3.38; found: C 86.93,
5
,10,15,20-Tetrakis[4-(9,9-dihexyl-9H-fluoren-2-yl)phenyl]porphyrin (3):
[16] [17]
Compound 12 (93 mg, 0.1 mmol), 13 (156 mg, 0.41 mmol), tetrakis-
(triphenylphosphine)palladium(0) (13.8 mg, 0.012 mmol) and sodium car-
AHCTREUNG
bonate (53 mg, 0.5 mmol) were stirred together in a degassed solution of
THF (12 mL), toluene (12 mL) and water (0.5 mL) at 1058C for 24 h.
The solution was allowed to cool to room temperature and the solvents
were removed in vacuo.The residue was redissolved in dichloromethane
(20 mL) and washed with water (30 mL) before being dried over anhy-
drous magnesium sulphate.After removal of the solvent in vacuo and
Figure 8.Luminance versus current density for the device ITO/PE-
DOT:PSS/PSBF copolymer:3/Ba/Al (5% by weight of 3 in the blend).
AHCTREUNG
1
2
(
7
8
70–2718C; H NMR (400 MHz, CDCl
3
): d=À2.59 (2H, s), 0.88–0.72
Conclusion
56H, m), 1.19–1.07 (48H, m), 2.18–2.05 (16H, m), 7.43–7.33 (12H, m),
.80 (4H, dd, J=7.2, J=0.9 Hz), 7.92–7.90 (12H, m), 8.10 (8H, d, J=
.4 Hz), 8.36 (8H, d, J=8.4 Hz), 9.03 ppm (8H, s); C NMR (100 MHz,
CDCl ): d=12.99, 21.60, 22.85, 28.77, 30.53, 39.53, 54.30, 118.83, 119.01,
119.16, 120.53, 121.95, 124.40, 125.20, 125.84, 126.14, 134.14, 138.51,
39.79, 139.83, 139.86, 140.04, 150.06, 150.69 ppm; MS (MALDI-TOF):
m/z: 1945.4 [M+H] ; elemental analysis calcd (%) for C144
8.11, H 8.22, N 2.85; found: C 87.89, H 8.24, N 2.83.
3
4
3
We have synthesized a series of porphyrin, phthalocyanine
and pyrazinoporphyrazine derivatives which bear four or
eight peripheral fluorenyl substituents.The compounds are
deep-red emitters: for example, lmax(em)=659 (3), 737 (8)
and 684 nm (9).A general feature of these systems is the
fast and efficient energy transfer, which occurs from the flu-
orenyl substituents to the macrocyclic cores.The emission
from the zinc-centred porphyrin derivatives 5 and 6 is signif-
icantly blue-shifted and the F and t values are greatly re-
3
13
3
1
+
158 4 2
H N ·H O: C
8
2
,3,9,10,16,17,23,24-Octakis(9,9-dihexyl-9H-fluoren-2-yl)-29H,31H-phtha-
locyanine (8): Lithium (20 mg, 2.88 mmol) was added to a stirred solution
of 17 (400 mg, 0.504 mmol) in degassed 1-pentanol (2 mL). The mixture
was heated at 1258C for 2 h and then allowed to cool to room tempera-
ture.The dark solution was acidified with 37% aq HCl (1 mL) and
poured into methanol (100 mL) forming a bright green precipitate, which
was then filtered to give a crude green solid (0.094 g). Purification by
column chromatography (eluent: 40% dichloromethane in hexane) gave
8 as a green solid (42 mg, 11%).M p. .325–327 8C; H NMR (300 MHz,
): d=0.58 (32H, m), 0.68 (48H, t, J=6.6 Hz), 0.97 (96H, m), 1.82
32H, m), 7.30 (24H, m), 7.52 (8H, m), 7.64–7.77 (24H, m), 9.64 ppm
f
f
duced compared to their free-base precursors 3 and 4, re-
spectively, demonstrating the effective reduction of fluores-
cence from the porphyrin by inter-system crossing to the ex-
cited triplet state.These are promising OLED materials as
demonstrated by a device using porphyrin-fluorene hybrid 3
blended into the blue polyspirobifluorene copolymer host.
Deep-red emission (lmax =665 nm) was observed from the
1
3
CDCl
(
(
3
13
3
8H, brs), NH protons not observed; C NMR (125 MHz, CDCl ): d=
14.05, 22.32, 24.01, 29.97, 31.89, 40.33, 55.57, 120.01, 120.03, 123.57,
125.93, 126.04, 127.21, 127.85, 129.98, 136.11, 140.56, 141.23, 144.76,
À2
device with an EQE of 2.5% (at 7.5 mAcm ), a low turn-
6716
www.chemeurj.org
ꢀ 2007 Wiley-VCH Verlag GmbH & Co.KGaA, Weinheim
Chem. Eur. J. 2007, 13, 6710 – 6717

Porphyrin, Phthalocyanine and Porphyrazine Derivatives
FULL PAPER
1
1
7
51.85, 151.97 ppm; IR (Nujol): 3175, 2933, 2911, 2853, 2714, 2656, 2595,
735, 1459, 1376, 1298, 1219, 1201, 1144, 1070, 946, 909, 873, 837, 759,
20, 511 cm ; MS (MALDI-TOF): m/z: 3173, 3174, 3175, 3176 [M] ; ele-
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Bryce, Appl. Phys. Lett. 2005, 86, 121101.
À1
+
mental analysis calcd (%) for C232
found: C 87.30, H 8.56, N 2.91.
274 8 2
H N ·H O: C 87.28, H 8.71, N 3.51;
[10] B.Li, J.Li, Y.Fu, Z.Bo,
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[
[
(
2 mL) and the solution was stirred at 1058C for 12 h.The solution was
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(
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[
Tetrahedron Lett. 1986,
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(
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1
M.p. >4008C; H NMR (300 MHz, CDCl
80H, m), 1.88 (32H, m), 7.34 (32H, m), 7.57–7.74 ppm (56H, m), NH
protons not observed; IR (Nujol): 3162, 2911, 2852, 2710, 2658, 2032,
3
): d=0.71 (96H, m), 1.03
(
1
5
610, 1489, 1376, 1299, 1219, 1174, 1070, 986, 919, 873, 837, 759, 720,
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Published online: May 24, 2007
Chem. Eur. J. 2007, 13, 6710 – 6717
ꢀ 2007 Wiley-VCH Verlag GmbH & Co.KGaA, Weinheim
www.chemeurj.org
6717