Synthesis of diazadibenzoperylenes and characterization of their structural, optical, redox, and coordination properties

Article abstract of DOI:10.1021/jo011133l

Tetraphenoxy-substituted diazadibenzoperylenes 5a,b were synthesized from tetrachloroperylene tetracarboxylic acid bisanhydride 1 through imidization with benzylamine, nucleophilic displacement of the four chlorine atoms by phenolates, carbonyl group reduction by LiA1H₄/A1C1₃, and subsequent Pd/C-promoted debenzylation-dehydrogenation. The structural properties of these extended diazaarenes are discussed on the basis of a X-ray crystal structure of the N,N'-dibutylated diazadibenzoperylenium dication 6, which revealed a 25° twist of the central six-membered ring leading to an atropisomeric π-conjugated backbone. The chromophoric systems of 5 and 6 were characterized by optical absorption and fluorescence spectroscopy, which revealed an intense fluorescence with a quantum yield of 75% for 5 and 50% for 6. Cyclic voltammetry showed reversible oxidation and reduction waves for 6, whereas the oxidation of 5 afforded the irreversible deposition of a conductive film on the electrode surface. Finally, the potential use of ligands 5 in supramolecular chemistry has been evaluated by complexation experiments with carboxylic acids and zinc tetraphenylporphyrin (ZnTPP).

Full text of DOI:10.1021/jo011133l

J . Org. Chem. 2002, 67, 3037-3044
3037
Syn th esis of Dia za d iben zop er ylen es a n d Ch a r a cter iza tion of Th eir
Str u ctu r a l, Op tica l, Red ox, a n d Coor d in a tion P r op er ties
Frank Wu¨rthner,*,† Armin Sautter,† and J oachim Schilling‡
Abteilung Organische Chemie II, Universita¨t Ulm, Albert-Einstein-Allee 11, D-89081 Ulm, Germany, and
Abteilung RB-OD, Deutsches Zentrum fu¨r Luft- und Raumfahrt e.V., Mu¨nchner Str. 20,
D-82234 Weâling, Germany
frank.wuerthner@chemie.uni-ulm.de
Received December 7, 2001
Tetraphenoxy-substituted diazadibenzoperylenes 5a ,b were synthesized from tetrachloroperylene
tetracarboxylic acid bisanhydride 1 through imidization with benzylamine, nucleophilic displacement
of the four chlorine atoms by phenolates, carbonyl group reduction by LiAlH4/AlCl3, and subsequent
Pd/C-promoted debenzylation-dehydrogenation. The structural properties of these extended
diazaarenes are discussed on the basis of a X-ray crystal structure of the N,N′-dibutylated
diazadibenzoperylenium dication 6, which revealed a 25° twist of the central six-membered ring
leading to an atropisomeric π-conjugated backbone. The chromophoric systems of 5 and 6 were
characterized by optical absorption and fluorescence spectroscopy, which revealed an intense
fluorescence with a quantum yield of 75% for 5 and 50% for 6. Cyclic voltammetry showed reversible
oxidation and reduction waves for 6, whereas the oxidation of 5 afforded the irreversible deposition
of a conductive film on the electrode surface. Finally, the potential use of ligands 5 in supramolecular
chemistry has been evaluated by complexation experiments with carboxylic acids and zinc
tetraphenylporphyrin (ZnTPP).
In tr od u ction
carboxylic acids, Lewis acidic boron compounds, and
metal centers.3 In particular, ditopic building blocks such
as pyrazine, 4,4′-bipyridine, and diazapyrene have been
used to construct sandwich complexes with coordinated
metalloporphyrins, catenanes and rotaxanes, molecular
squares with ligand-bridged Pd(II) and Pt(II) corners,
cage compounds, polymeric aggregates, or solid-state
networks.4 Recently, we introduced an extended and
functionally enriched version of these π-systems, i.e.,
diazadibenzoperylene 5a ,5 which proved to exhibit excit-
ing supramolecular properties including the formation
of triangular and square metallacycles upon coordination
to cis-Pt(II) and cis-Pd(II) metal corners6 as well as the
formation of columnar liquid crystals after covalent or
hydrogen-bonded attachment of mesogenic substituents.7
In this paper, we give details about the synthesis of these
interesting supramolecular building blocks and describe
their structural, optical, and electrochemical properties
as well as the strength of their noncovalent interaction
Supramolecular architectures of π-conjugated mol-
ecules are often compared to the noncovalently assembled
dye aggregates found in the light-harvesting complexes
of photosynthetic plants and bacteria.1,2 Inspired by the
intriguing functionality of the natural assemblies, most
of the artificial mimicries presently available are based
on bio-inspired chromophores such as porphyrins, chlo-
rines, and carotenes.1 However, to realize different kinds
of functionality in supramolecular assemblies that might
open attractive applications in fields such as (supra-)-
molecular electronics, solar cells, or field effect transis-
tors, a higher structural and functional diversity of the
available dyes is desirable. To be useful for such goals,
the respective dyes should contain suitably positioned
receptor groups for directional intermolecular interac-
tions, high solubility, as well as favorable optical and/or
electrochemical properties.
Among the most widely used receptor groups in su-
pramolecular chemistry are azaaromatic Lewis bases
that can form strong intermolecular interactions with
(3) (a) Lehn, J .-M. Supramolecular Chemistry; VCH: Weinheim,
1995. (b) Comprehensive Supramolecular Chemistry; Lehn, J .-M.,
Atwood, J . L., Davies, J . E. D., MacNicol, D. D., Vo¨gtle, F., Eds.;
Pergamon: Oxford, 1996; Vols. 1-11. (c) Steed, J . W.; Atwood, J . L.
Supramolecular Chemistry; Wiley: West Sussex, 2000.
(4) (a) Anderson, H. L.; Hunter, C. A.; Nafees Meah, M.; Sanders,
J . K. M. J . Am. Chem. Soc. 1990, 112, 5780. (b) Fujita, M. J . Synth.
Org. Chem. J pn. 1996, 54, 953. (c) Leininger, S.; Olenyuk, B.; Stang,
P. J . Chem. Rev. 2000, 100, 853 and references therein. (d) Vreekamp,
R. H.; Verboom, W.; Reinhoudt, D. J . Org. Chem. 1996, 61, 4282. (e)
Subramanian, S.; Zaworotko, M. J . Angew. Chem., Int. Ed. Engl. 1995,
34, 2127. (f) Valiyaveettil, S.; Enkelmann, V.; Moeâner, G.; Mu¨llen,
K. Macromol. Symp. 1996, 102, 165. (g) Philp, D.; Stoddart, F. Angew.
Chem., Int. Ed. Engl. 1996, 108, 1242.
* To whom correspondence should be addressed. Fax: +49 731
5022840.
† Universita¨t Ulm.
‡ Deutsches Zentrum fu¨r Luft- und Raumfahrt.
(1) (a) Schenning, A. P. H. J .; Benneker, F. B. G.; Geurts, H. P. M.;
Liu, X. Y.; Nolte, R. J . M. J . Am. Chem. Soc. 1996, 118, 8549. (b) Van
Nostrum, C. F.; Picken, S. J .; Schouten, A.-J .; Nolte, R. J . M. J . Am.
Chem. Soc. 1995, 117, 9957. (c) Engelkamp, H.; Middelbeek, S.; Nolte,
R. J . M. Science 1999, 284, 785.
(2) (a) Wu¨rthner, F. Nachrichten fu¨r Chemie 2001, 49, 1284. (b)
Wu¨rthner, F.; Thalacker, C.; Sautter, A. Adv. Mater. 1999, 11, 754.
(c) Wu¨rthner, F.; Thalacker, C.; Sautter, A.; Scha¨rtl, W.; Ibach, W.;
Hollricher, O. Chem. Eur. J . 2000, 6, 3871. (d) Wu¨rthner, F.; Sautter,
A.; Schmid, D.; Weber, P. J . A. Chem. Eur. J . 2001, 7, 894. (e)
Wu¨rthner, F.; Thalacker, C.; Diele, S.; Tschierske, C. Chem. Eur. J .
2001, 7, 2245.
(5) (a) Wu¨rthner, F.; Sautter, A.; Thalacker, C. Angew. Chem., Int.
Ed. 2000, 39, 1243. (b) Sautter, A. Diploma Thesis, Universita¨t Ulm,
Germany 1997.
(6) Sautter, A.; Schmid, D.; J ung, G.; Wu¨rthner, F. J . Am. Chem.
Soc. 2001, 123, 5424.
(7) Sautter, A.; Thalacker, C.; Wu¨rthner, F. Angew. Chem., Int. Ed.
2001, 40, 4425.
10.1021/jo011133l CCC: $22.00 © 2002 American Chemical Society
Published on Web 04/10/2002

3038 J . Org. Chem., Vol. 67, No. 9, 2002
Wu¨rthner et al.
Sch em e 1
Ta ble 1. Op tim iza tion of th e
to carboxylic acids and zinc metal ions of zinc tetraphe-
nylporphyrins (ZnTPP).
Deben zyla tion -Deh yd r ogen a tion Rea ction of 4a w ith
P d /Ca
solvent
T (°C)
t (h)
isolated yield (%)
Resu lts a n d Discu ssion
naphthalene
cumene
diphenyl ether
toluene
218
152
170
111
2
4
6
9
30
28
48
-
Syn th esis. The synthesis of core-substituted diaza-
dibenzoperylenes 5a ,b follows the strategy outlined in
Scheme 1, which was inspired by the synthesis of 2,7-
diazapyrene described by Hu¨nig et al.8 and of 2,9-
diazadibenzoperylene by Stang et al.9a Tetrachloro-
perylene bisanhydride 1 was reacted with butyl- and
benzylamine in propionic acid to give the tetrachloro-
perylene bisimides 2a ,b. In this reaction, not only the
nitrogen atoms are introduced but also two alkyl groups
that have to be removed in the last step. It was found
that the use of benzyl substituents is preferable over
butyl, as benzyl groups sufficiently solubilize the perylenes
2-4 and can be cleaved under rather mild conditions
(vide infra). The subsequent displacement of the chlorines
by phenolate and 4-tert-butylphenolate yielded tetraphe-
noxyperylene bisimides 3a -d ,2,10 which could be reduced
by lithiumaluminum hydride/aluminum chloride to give
the amines 4a -c. However, the final step, which requires
both cleavage of alkyl groups and aromatization by
dehydrogenation, imposed difficulties. Application of
standard reaction conditions described in the literature8,9
were not successful.5b For example, typical dehydroge-
a
The reactions were terminated when no more 4a was detected
by thin-layer chromatography.
nations by Pd/C are conducted in the molten state of the
compounds at about 300 °C, conditions that are not
applicable to the thermally rather sensitive amines 4a -
c. For 4a ,b, decomposition is already complete when the
compounds are molten (TLC check), and even storage at
ambient conditions (room temperature, air) leads to slow
decomposition that manifests in a color change from
bright yellow to dark brown. For this reason, the aro-
matization reaction with Pd/C had to be optimized, which
was possible for the benzylated compounds 4a ,b by
lowering the reaction temperature and conducting the
reaction in an appropriate solvent9c (Table 1).
According to Table 1, the reaction of 4a in boiling
naphthalene at 218 °C afforded a considerably improved
yield. Similar results were obtained at 152 °C in refluxing
cumene, but still decomposition was predominant. When
the temperature was further decreased to 111 °C in
boiling toluene, no conversion took place anymore. Fi-
nally, upon changing to diphenyl ether as solvent, less
decomposition and side reactions were noted leading to
the best yields at a temperature of 170 °C (6 h, 48%).
Below 170 °C, the reaction was found to be rather slow,
and above this temperature decomposition rapidly in-
creased. These conditions (diphenyl ether, 170 °C, 6 h)
could be successfully applied for the synthesis of diaza-
(8) Hu¨nig, S.; Groâ J .; Lier, E. F.; Quast, H. Liebigs Ann. Chem.
1973, 339.
(9) (a) Stang, P. J .; Cao, D. H.; Saito, S.; Arif, A. M. J . Am. Chem.
Soc. 1995, 117, 6272. (b) Fu, P. P.; Harvey, R. G. Chem. Rev. 1978, 78,
317. (c) Chen, Q.; Deady, L. W. Aust. J . Chem. 1993, 46, 987.
(10) (a) Seybold, G.; Wagenblast, G. Dyes Pigm. 1989, 11, 303. (b)
Dotcheva, D.; Klapper, M.; Mu¨llen, K. Macromol. Chem. Phys. 1994,
195, 1905. (c) Schneider, M.; Mu¨llen, K. Chem. Mater. 2000, 12, 352.
(d) Lee, S. K.; Zu, Y.; Herrmann, A.; Geerts, Y.; Mu¨llen, K.; Bard, A.
J . J . Am. Chem. Soc. 1999, 121, 3513.

Synthesis of Diazadibenzoperylenes
J . Org. Chem., Vol. 67, No. 9, 2002 3039
dibenzoperylene 5b in 56% isolated yield. Despite the
extended aromatic surfaces and the lack of solubilizing
alkyl chains in 5a ,b, these compounds exhibit a remark-
able solubility. For example, the solubility of 5a in
dichloromethane exceeds 300 g L-1 and is still 0.6 g L-1
in cylohexane.
Str u ctu r a l P r op er ties. An unsuccessful effort in the
synthesis of diazadibenzoperylene 5a involved the N,N′-
dibutylated derivative 4c, but failed in the removal of
the butyl groups in the final high-temperature aromati-
zation step.5b However, oxidation of the N,N′-dibutyl-
substituted perylene diamine 4c with mercury(II) ac-
etate8 gave the N,N′-dibutyldiazadibenzoperylenium
dication whose precipitation with tetrafluoroborate an-
ions afforded well-defined crystals of 6.
F igu r e 1. Structure of 6 (M enantiomer) in the crystal
(ORTEP plot). The hydrogen atoms and BF4- counterions were
omitted for clarity. (A) Top view and (B) view along the N-N
axis showing the twisted diazadibenzoperylene backbone
(Θ ) 25°).
This is remarkable as core-substituted perylene de-
rivatives do not crystallize well,2,10 and only one crystal
structure of a phenoxy-substituted perylene derivative
has been reported so far.11 On the other hand, many
crystal structures are known for unsubstituted perylene
bisimide pigments that have been thoroughly studied by
Graser and Ha¨dicke.12
these highly interesting chiral dyes failed,14 and their
structural features could now be characterized for the
first time in the crystalline state. In addition to the
interesting implications of this twisting with regard to
future work directed toward chiral dyes, this prominent
twisting of the aromatic backbone is also considered to
be of major importance for the excellent solubility of dyes
5 and 6 because it interferes with the stacking of the
π-conjugated systems.
The crystals belong to the monoclinic space group P21/n
with four molecules in the unit cell (Z ) 4), i.e., two P
and two M enantiomers of 6. The arrangement of the
molecules can be best visualized in a stereoview along
the c-axis (Figure 2A,B), revealing a herringbone motif
of tilted stacks of molecules that form layers. The
diazadibenzoperylene backbones are oriented perpen-
dicular with respect to the layer planes. The arrangement
of the molecules within a layer and with respect to the
next layer is sketched in a simplified way in Figure 2C.
All molecules within a layer are of the same enantiomer,
i.e., the dark molecules (top layer) are the M enantiomers
and the light molecules (bottom layer) are the P enantio-
mers. Centers of symmetry (points of inversion) are
located between the layers and bring the P enantiomers
into coincidence with the M enantiomers, and vice versa
(3 T 4 in Figure 2C). Furthermore, there are screw axes
in the direction perpendicular to the stacks. A rotation
around this axis by 180° followed by a translation brings
the like enantiomers into superposition (1 T 2 in Figure
2C).
Single crystals suitable for X-ray crystal structure
analysis were obtained by layering a solution of 6 in
dichloromethane/methanol with diethyl ether. An ORTEP
plot of 6 is depicted in Figure 1. As expected, all C-C
bond lengths of the diazadibenzoperylene backbone are
between 1.35 and 1.45 Å, which confirms a high degree
of conjugation and aromaticity (Figure 1A).13 Owing to
the electrostatic repulsion between the oxygen atoms of
the phenoxy substituents, the central six-membered ring
gets twisted by 25° (Figure 1B) leading to an axial
chirality with P and M enantiomers of 6. The crystal of
6 is racemic, and both enantiomers are found in a 1:1
ratio in the crystallographic unit cell (only the M enan-
tiomer is displayed in Figure 1). Axial chirality of
tetraphenoxy-substituted perylenes is a conformational
isomerism, and the energy barrier for the interconversion
between the two enantiomers in solution is supposed to
be very low. As a consequence, earlier attempts to isolate
(11) (a) Quante, H. Ph.D. Thesis, Universita¨t Mainz, Germany, 1995.
(b) A X-ray crystal structure of an 8-fold chlorinated perylene bisimide
has also been reported: Sadrai, M.; Bird, G. R.; Potenza, J . A.; Schugar,
H. J . Acta Crystallogr. C 1990, 46, 637.
(12) (a) Graser, F.; Ha¨dicke, E. Liebigs Ann. Chem. 1980, 1994. (b)
Graser, F.; Ha¨dicke, E. Liebigs Ann. Chem. 1984, 483. (c) Klebe, G.;
Graser, F.; Ha¨dicke, E.; Berndt, J . Acta Crystallogr. B 1989, 45, 69.
(13) The 1H NMR resonance for the protons R to the nitrogens
changes from δ ) 3.79 (4c) to 9.21 (5a ) and 9.92 ppm (6) supporting a
high degree of conjugation and aromaticity within the diazadibenzo-
perylene backbone. The perylene core protons appear at δ ) 8.03 ppm
for 6 and at 7.52 ppm for 5a .
(14) (a) Hien, S. Diploma Thesis, Universita¨t Regensburg, Germany,
1992. (b) Hien, S. Ph.D. Thesis, Universita¨t Regensburg, Germany,
1995.

3040 J . Org. Chem., Vol. 67, No. 9, 2002
Wu¨rthner et al.
F igu r e 2. (A, B) Stereoview of the molecular packing in the crystal along the c-axis. (C) Simplified sketch of the molecular
packing: the dark (M enantiomers) and the light (P enantiomers) rectangles each represent molecules within a layer (herringbone
motif). The anions are located between the layers and are depicted as gray circles. One screw axis (within the layer) and one
center of symmetry (between the layers) are depicted.
The cyclic voltammograms (CV) of diaza ligands 5a ,b
show one reversible wave in the reductive cycle between
-1.70 and -1.80 V (vs Fc/Fc+), where reduction to the
radical anions 5•- occurs (Figure 4A). Oxidation is ir-
reversible and accompanied by adsorption of the oxidized
species on the platinum electrode surface. Repeated
oxidation cycles lead to the growth of a film on the
electrode as indicated by an increase in current with each
scan (Figure 5A). Characterization of the coated electrode
in a monomer-free electrolyte reveals multiple redox
couples in the CV, suggesting the formation of an
electroactive polymer of unknown chemical structure
(Figure 5B).
For diazadibenzoperylenium dications (6), two revers-
ible waves are observed at significantly higher electrode
F igu r e 3. UV/vis absorption and fluorescence spectra of 5a
potentials than for 5a ,b in the reductive cycle, which
(s) and 6 (- - -) in dichloromethane.
suggest the reduction of 6 to the neutral antiaromatic
π-system 7 via a radical cationic intermediate.
No distances typical for π-π interactions are found
between the extended aromatic diazadibenzoperylene
surfaces as they are within a distance of about 10 Å. This
might be a consequence of electrostatic repulsion of the
charged π-systems, which might also be responsible for
the tilted arrangement of the molecules in the stacks.
The tetrafluoroborate anions are located between the
layers in proximity to the positive charges at the nitrogen
atoms. It therefore seems that the packing of the mol-
ecules in the crystal is mainly controlled by electrostatic
ionic interactions.
Op tica l a n d Electr och em ica l P r op er ties. The UV/
vis absorption spectra of diazadibenzoperylenes 5a ,b are
characterized by intense S0-S1 absorption bands located
at λ ) 497 ( 1 nm (0-0 vibronic transition) and λ ) 465
( 1 nm (first vibronic progression) in dichloromethane.
The fluorescence emission spectra are close mirror images
of the absorption spectra and display maxima at λ ) 514
( 2 nm. No effect of the different phenoxy substituents
on the optical absorption and fluorescence properties are
found for compounds 5a ,b. Upon alkylation of the two
nitrogens, an additional shoulder appears in the UV/vis
absorption spectrum of 6 at the long-wavelength side of
the S0-S1 transition leading to a bathochromically shifted
fluorescence (λmax ) 545 ( 2 nm) with a well-defined
vibronic progression (Figure 3). The fluorescence quan-
tum yields ΦF are 0.75 ( 0.05 for the compounds 5a ,b
and 0.50 ( 0.05 for 6.
In the oxidative cycle, an additional reversible oxida-
tion to the radical trication is possible, because 6, in
contrast to 5, does not contain lone pairs of electrons at
the nitrogen atoms that are susceptible to adsorption at
the electrode surface and facile irreversible oxidation
(Figure 4B).
Coor d in a t ion P r op er t ies. The suitability of diaza
ligand 5a as a supramolecular building block was evalu-
ated by complexation experiments in chloroform and
tetrachloromethane with highly soluble Bro¨nsted and
Lewis acids, i.e., 3,4,5-tridodecyloxybenzoic acid (TBA)
and zinc tetraphenylporphyrin (ZnTPP) (Scheme 2). For
each experiment, changes in the environment of the

Synthesis of Diazadibenzoperylenes
J . Org. Chem., Vol. 67, No. 9, 2002 3041
Sch em e 2
F igu r e 4. Cyclic voltammogram of 5a (A) and 6 (B) in
dichloromethane (sweep rate 100 mV s-1).
(Figure 6a).15 More pronounced changes in the chemical
shift of the R-proton from δ ) 9.22 (free ligand) to 2.90
ppm (calculated for fully coordinated ligand) were ob-
served when 5a was titrated with ZnTPP in CDCl3 giving
a binding constant K of 1500 M-1 (Figure 6b). The same
value was obtained when the shift of the more distant
diazadibenzoperylene γ-proton was evaluated which still
receives a substantial shielding from 7.55 ppm (free) to
5.90 ppm (fully coordinated). Clearly, these large upfield
shifts are not a result of the coordination of Lewis acidic
metal centers but due to the coordination of the diaza
ligand within the inner cone of the porphyrin ring
current, giving unambiguous proof of the sandwich
complex structure 10 suggested in Scheme 2.
If the same NMR titration experiment is carried out
in the less polar solvent CCl4, an increase of the binding
constant K to 3900 M-1 is observed that indicates a
notable electrostatic contribution for the metal-ligand
coordination as expected from crystal field theory. The
latter self-assembly process that leads to a double-decker
2:1 complex (Scheme 2) could also be verified by a UV/
vis titration experiment in tetrachloromethane operating
within a different concentration range. Here, ZnTPP was
selected as the host and pronounced changes of the
porphyrin Q-bands upon addition of 5b (Figure 7) could
be evaluated applying the whole data set in a global
fitting procedure.16 Owing to the large number of experi-
mental data points given for UV/vis spectra this experi-
ment allowed us to extract the individual binding con-
stants for the formation of a 1:1 complex between 5a and
ZnTPP (K1 ) 1.1 × 104 L mol-1) and the subsequent
formation of the 1:2 double sandwich complex (K2 ) 4.2
× 103 L mol-1).16 From the functional point of view, it is
noteworthy that the photoluminescence of the diaza-
dibenzoperylene fluorophore is completely quenched upon
complexation of the zinc porphyrins, which is probably a
result of a photoinduced electron-transfer process.17
F igu r e 5. (A) Cyclic voltammograms of repeated oxidation
scans for 5a in dichloromethane indicating the growth of an
electroactive film on the platinum electrode. (B) Characteriza-
tion of the electroactivity of the adsorbed film in a monomer-
free electrochemical cell by cyclic voltammetry (sweep rate 100
mV s-1).
diazadibenzoperylene ligand () host) were monitored
upon addition of the binding partner () guest) by 1H
NMR spectroscopy and from the titration curves binding
constants15 were calculated by nonlinear regression
analysis under the assumption of two independent bind-
ing events. Complexation of 5a with TBA in CDCl3
results in a very small change of the chemical shift of
the R-protons next to the complexing nitrogen atoms from
δ ) 9.22 to 9.28 ppm. From the binding isotherm a
microscopic binding constant K of 140 M-1 is obtained
(15) All titration experiments were evaluated by assuming two
independent receptor sites for diazadibenzoperylene 5a and a negligible
self-association of the guests TBA and ZnTPP within the investigated
concentration range. All given binding constants are “microscopic”
binding constants for individual binding events between two species.
Owing to the well-known dimerization of carboxylic acids we note that
the assumption of negligible self-association is critical in the case of
TBA whereas for ZnTPP self-aggregation could be ruled out in the
given concentration range by concentration-dependent UV/Vis absorp-
tion spectra. For a review about the coordination chemistry of metal-
loporphyrins, see: Wojaczynski, J .; Latos-Grazynski, L. Coord. Chem.
Rev. 2000, 204, 113.
(16) SPECFIT/32 for Windows 95/98 & NT 4.0/2000 from Spectrum
Software Associates: Marlborough, MA, 2000-2001.

3042 J . Org. Chem., Vol. 67, No. 9, 2002
Wu¨rthner et al.
F igu r e 7. UV/vis titration of ZnTPP with 5a . The arrows
indicate the spectral changes of the porphyrin Q-bands upon
addition of ligand 5a .
Exp er im en ta l Section
Ma ter ia ls a n d Meth od s. Solvents and reagents were
purified and dried according to standard procedures.18 3,4,5-
Tridodecyloxybenzoic acid,19 trans-[Pd(PPh3)2][(OTf)2],20 and
zinc tetraphenylporphyrin (ZnTPP)21 were synthesized accord-
ing to the literature. 1,6,7,12-Tetrachloroperylene-3,4:9,10-
tetracarboxylic acid bisanhydride22 was donated by BASF AG.
The solvents for spectroscopic studies were of spectroscopic
grade and used as received. Fluorescence spectra were mea-
sured on a calibrated fluorometer in 1 cm quartz cells. All
fluorescence spectra were corrected. Fluorescence quantum
yields were determined relative to fluorescein in 0.1 N NaOH
(ΦR ) 0.9)23 by the optically dilute method24 (A e 0.05) in
dichloromethane. Cyclic voltammetry was performed in a
three-electrode single-compartment cell with dichloromethane
as solvent (5 mL): Working electrode: platinum disk; counter
electrode: platinum wire; reference electrode: Ag/AgCl. All
potentials were internally referenced to the Fc/Fc+ couple. The
solutions were purged with argon prior to use. The supporting
electrolyte was 0.1 M [Bu4N][PF6], which was recrystallized
twice from ethanol/water and dried in a high vacuum.
F igu r e 6. (A) Saturation plot showing the amount (%) of
complexed aza receptor sites X (5a *) for titration experiments
with ZnTPP (squares) and TBA (triangles) in CDCl3. (B) Three
selected 1H NMR spectra for the titration of 5a with ZnTPP
in CDCl3. The arrows indicate the change in chemical shift of
the protons R to the coordinating nitrogens from δ ) 9.22 (first
spectrum without ZnTPP) to 3.53 ppm (third spectrum with a
10-fold excess of ZnTPP).
NMR Titr a tion Exp er im en ts. All NMR titrations were
performed at
a constant diazadibenzoperylene receptor
() host) concentration of 7 mmol L-1 5a for the titration with
TBA and of 3 mmol L-1 5a for the titration with ZnTPP in
CDCl3 at a temperature of 298 K. Aliquots of a guest solution
containing 35 mmol L-1 of TBA and 15 mmol L-1 of ZnTPP,
respectively, were subsequently added to an NMR tube
containing an initial volume of 350 µL of the 5a host solution.
After each addition, a spectrum was recorded. For the titration
of 5a with ZnTPP in CCl4, a special NMR tube with a sealed
capillary containing deuterated acetone for lock-in was used.
The experiment was carried out in the same way as described
above with concentrations of 1.2 mmol L-1 (5a ) and 3.7 mmol
L-1 (ZnTPP) and a starting host volume of 350 µL. The binding
constants were evaluated by nonlinear least-squares regres-
sion analysis from the change in chemical shift of the diaza-
dibenzoperylene HR protons.13
Con clu sion s
New functional supramolecular building blocks 5a ,b
based on core-substituted diazadibenzoperylene dyes
could be synthesized in four steps from tetrachloroperyle-
nebisanhydride 1 in an overall yield of 16%. These dyes
exhibit favorable optical (strong absorption, yellow emis-
sion with high quantum yield) and electrochemical
(reversible reduction) properties as well as an extremely
high solubility that enables self-assembly processes to be
carried out over a wide concentration range. Complex-
ation studies of the diazadibenzoperylene ligands to
carboxylic acids and zinc porphyrins proved their suit-
ability for the design of novel functional supramolecular
architectures such as double decker sandwich complexes
with metalloporphyrins (10), metallacycles,6 as well as
liquid crystals.7
UV/vis Titr a tion Exp er im en ts. The titration was per-
formed at 5 × 10-4 mol L-1 constant ZnTPP () host) concen-
(18) Perrin, D. D.; Armarego, W. L. F. Purification of Laboratory
Chemicals, 2nd ed.; Pergamon Press: Oxford, 1980.
(19) Meier, H.; Praâ, E.; Zerban, G.; Kosteyn, F. Z. Naturforsch. B
1988, 43, 889.
(20) Murata, S.; Ido, Y. Bull. Chem. Soc. J pn. 1994, 67, 1746.
(21) (a) Adler, A. D.; Longo, F. R.; Finarelli, J . D.; Goldmacher, J .;
Assour, J .; Korsakoff, L. J . Org. Chem. 1967, 32, 476. (b) Fuhrhop, J .
H.; Smith, K. M. Laboratory Methods in Porphyrin and Metallopor-
phyrin Research; Elsevier: New York, 1975.
(22) Sadrai, M.; Hadel, L.; Sauers, R. R.; Husain, S.; Krogh-
J espersen, K.; Westbrook, J . D.; Bird, G. R. J . Phys. Chem. 1992, 96,
7988.
(23) Becker, H. G. O. Einfu¨hrung in die Photochemie; Thieme:
Stuttgart, 1983.
(17) (a) Berg, A.; Shuali, Z.; Asano-Someda, M.; Levanon, H.; Fuhs,
M.; Mo¨bius, K.; Wang, R.; Brown, C.; Sessler, J . L. J . Am. Chem. Soc.
1999, 121, 7433. (b) Myles, A. J .; Branda, N. R. J . Am. Chem. Soc.
2001, 123, 177.
(24) Demas, J . N.; Crosby, G. A. J . Phys. Chem. 1971, 75, 991.

Synthesis of Diazadibenzoperylenes
J . Org. Chem., Vol. 67, No. 9, 2002 3043
tration in CCl4 at 298 K. Aliquots of the guest solution
containing 2 × 10-3 mol L-1 of 5a and 5 × 10-4 mol L-1 of
ZnTPP were subsequently added to a cell (optical path length
d ) 0.1 cm) containing an initial volume of 100 µL of ZnTPP
host solution. After each addition, a spectrum was recorded.
The association constant was evaluated in a 1:2 model by a
global nonlinear regression analysis taking into consideration
the whole set of available spectral data between 520 and 640
nm.16
tion was accomplished by dissolving the crude product in CH2-
Cl2 and precipitation by MeOH followed by chromatography
on SiO2 with CH2Cl2: yield 6.60 g (70%); mp >300 °C; 1H NMR
(400 MHz, CDCl3, 25 °C, TMS) δ 8.20 (s, 4H), 7.45 (m, 4H),
7.29-7.18 (m, 14H), 7.10 (m, 4H), 6.93 (m, 8H), 5.29 (s, 4H);
UV/vis (CH2Cl2) λmax, nm (ꢀ, mol-1 dm3 cm-1) 575 (51 400), 536
(32 200), 446 (18 500), 284 (49 400), 264 (45 300); fluorescence
(CH2Cl2) λmax ) 606 nm; MS (FD, 8 kV) 938 (M+). Anal. Calcd
for C62H38N2O8 (938.3): C, 79.31; H, 4.08; N, 2.98. Found: C,
79.24; H, 4.39; N, 3.33.
Cr ysta l str u ctu r e a n a lysis of 6: C56H46B2F8N2O4, Mr )
984.60, monoclinic, space group P21/n (no.14), a ) 12.8868-
(16) Å, b ) 21.825(5) Å, c ) 17.688(2) Å, â ) 99.743(14)°, V )
4903.2(14) Å3, Z ) 4, Fcalcd ) 1.334 Mg m-3, µ(Mo KR) ) 0.103
mm-1, crystal size 0.19 × 0.31 × 0.62 mm, T ) 220 K, 9285
independent reflections collected, 682 parameters, R1 ) 0.0565
and wR2 ) 0.1366 for reflections with I > 2σ(I), max/min
residual electron density 0.419/-0.306 e Å-3. Data were
collected using a STOE-IPDS-diffractometer with monochro-
matic (graphite monochromator) Mo KR radiation (λ ) 0.710 73
Å, 2θmax ) 51.94°, 2θmin ) 4.08°); scanmodus rotation. The
structure was solved by direct methods (SHELXS 97)25 refine-
ment on F2 using the full-matrix least-squares-method
(SHELXL 97).26 Hydrogen atoms were set geometrically as
idealized CH2, CH3, and aromatic CH groups and treated using
a riding model. The tetrafluoroborate anions showed a strong
orientation disorder and were described and refined using 10
and 12 fluorine split sets, respectively, but the exact positions
of the fluorine atoms could not be determined.27 Crystal-
lographic data (excluding structure factors) for the structure
reported in this Chapter have been deposited with the Cam-
bridge Crystallographic Data Centre as supplementary pub-
lication no. CCDC-133189. Copies of the data can be obtained
free of charge on application to CCDC, 12 Union Road,
Cambridge CB21EZ, U.K. (fax: (+44) 1223-336-033; e-mail:
deposit@ccdc.cam.ac.uk).5a
N,N′-Dib en zyl-1,6,7,12-t et r a ch lor op er ylen e-3,4:9,10-
tetr a ca r boxylic Acid Bisim id e (2a ). A suspension of 1,6,7,-
12-tetrachloroperylene-3,4:9,10-tetracarboxylic acid bisanhy-
dride 1 (7.95 g, 15.0 mmol) and benzylamine (8.03 g, 8.2 mL,
75.0 mmol) in propionic acid (100 mL) was stirred under reflux
for 8 h. The product was isolated by filtration and washed with
saturated NaHCO3 and H2O and then dried at 100 °C in vacuo.
The product is sufficiently pure for further reactions but
contains small amounts of pentachloroperylenebisimide and
perylenemonoimide monoanhydride according to mass spec-
trometry: yield 9.70 g (91%); mp >300 °C; 1H NMR (400 MHz,
CDCl3, 25 °C, TMS) δ 8.69 (s, 4H), 7.55 (m, 4H), 7.36-7.27
(m, 6H), 5.41 (s, 4H); UV/vis (CH2Cl2) λmax nm (ꢀ, mol-1 dm3
cm-1) 520 (34 800), 487 (24 600), 427 (11 100), 270 (26 300);
fluorescence (CH2Cl2) λmax 551 nm; MS (FD, 8 kV) 708 (M+).
Anal. Calcd for C38H18Cl4N2O4 (708.4): C, 64.43; H, 2.56; N,
3.95. Found: C, 63.49; H, 2.57; N, 3.74.
N,N′-Diben zyl-1,6,7,12-tetr a (4-ter t-bu tylp h en oxy)p er y-
len e-3,4:9,10-tetr a ca r boxylic Acid Bisim id e (3b). Prepared
from perylene bisimide 2a (7.08 g, 10.0 mmol), 4-tert-butyl-
phenol (7.50 g, 50.0 mmol), K2CO3 (4.83 g, 35.0 mmol), and
NMP (150 mL) in the same way as described for 3a but with
stirring at 140 °C for 8 h: yield 8.10 g (69%); mp >300 °C; 1H
NMR (400 MHz, CDCl3, 25 °C, TMS) δ 8.23 (s, 4H), 7.44 (m,
3
4H), 7.30-7.19 (m, 14H), 6.81 (d, J (H,H) ) 8.8 Hz, 8H), 5.30
(s, 4H), 1.29 (s, 36H); UV/vis (CH2Cl2) λmax, nm (ꢀ, mol-1 dm3
cm-1) 582 (49 300), 542 (29 700), 453 (18 100), 286 (48 600),
266 (46 100); fluorescence (CH2Cl2) λmax 614 nm; MS (MALDI-
TOF, dithranol) 1162.6 (M+). Anal. Calcd for C78H70N2O8
(1163.4): C, 80.53; H, 6.06; N, 2.41. Found: C, 80.41; H, 6.13;
N, 2.29.
N,N′-Dib u t yl-1,6,7,12-t et r a p h en oxyp er ylen e-3,4:9,10-
tetr a ca r boxylic Acid Bisim id e (3c). Prepared from perylene
bisimide 2b (8.30 g, 13.0 mmol), phenol (5.36 g, 57.0 mmol),
K2CO3 (5.52 g, 40.0 mmol), and NMP (150 mL) as described
for 3a : yield 6.0 g (53%); mp >300 °C; 1H NMR (200 MHz,
CDCl3, 25 °C, TMS) δ 8.18 (s, 4H), 7.26 (t, 8H), 7.10 (t, 4H),
6.93 (d, 8H), 4.10 (t, 4H), 1.65 (m, 4H), 1.39 (m, 4H), 0.93 (t,
6H); UV/vis (CH2Cl2) λmax, nm 570, 532, 444, 284, 264; MS
(MALDI-TOF, dithranol) 870.3 (M+). Anal. Calcd for C56H42N2O8
(871.0): C, 77.23; H, 4.86; N, 3.22. Found: C, 77.10; H, 4.90;
N, 3.10.
N,N′-Dib u t yl-1,6,7,12-t et r a (4-ter t-b u t ylp h en oxy)p er -
ylen e-3,4:9,10-tetr a ca r boxylic Acid Bisim id e (3d ). Pre-
pared from perylene bisimide 2b (3.20 g, 5.0 mmol), 4-tert-
butylphenol (3.3 g, 22.0 mmol), K2CO3 (2.1 g, 15.0 mmol), and
NMP (50 mL) in the same way as described for 3a but with
1
stirring at 140 °C for 8 h: yield 3.0 g (56%) mp > 300 °C; H
NMR (200 MHz, CDCl3, 25 °C, TMS) δ 8.22 (s, 4H), 7.23 (d,
8H), 6.83 (d, 8H), 4.11 (t, 4H), 1.66 (m, 4H), 1.36 (m, 4H), 1.29
(s, 36H), 0.93 (t, 6H); MS (MALDI-TOF, dithranol) 1094.7 (M+).
Anal. Calcd for C72H74N2O8 (1095.4): C, 78.95; H, 6.81; N, 2.56.
Found: C, 78.60; H, 6.96; N, 2.36.
5,6,12,13-Tetr a p h en oxy-1,3,8,10-tetr a h yd r o-2,9-d iben -
zyl-2,9-d ia za d iben zo[cd ,lm ]p er ylen e (4a ). AlCl3 (7.48 g, 56
mmol) and LiAlH4 (2.13 g, 56 mmol) were added to dry THF
(300 mL) under argon and with cooling with an ice bath. The
cooling bath was removed, and perylene bisimide 3a (6.56 g,
7 mmol) was added in small portions. The mixture was stirred
at 35 °C for 6 h, poured into cold 0.3 N hydrochloric acid (1.4
L), and stirred for 1 h. The precipitate was suction filtered,
washed with H2O, and dried. It was suspended in methanol
(200 mL), and 1 N NaOH (50 mL) was added to precipitate
the yellow amine 4a , which was collected, washed to neutral,
dried, and purified by MPLC chromatography on Si60 (CH2-
N,N′-Dibu tyl-1,6,7,12-tetr a ch lor op er ylen e-3,4:9,10-tet-
r a ca r boxylic Acid Bisim id e (2b). As described for 2a
bisanhydride 1 (17.7 g, 33.4 mmol) and butylamine (9.8 g, 134
mmol) were reacted in propionic acid (200 mL) to afford 17.9
g (84%) of 2b: mp >300 °C; 1H NMR (200 MHz, CDCl3, 25 °C,
TMS) δ 8.68 (s, 4H), 4.22 (t, 4H), 1.74 (m, 4H), 1.49 (m, 4H),
1
1.00 (t, 6H); MS (FD, 8 kV) 640 (M+). Anal. Calcd for C32H22
-
Cl2/MeOH 97:3): yield 4.20 g (68%); mp 252 °C dec; H NMR
(500 MHz, CDCl3, 25 °C, TMS) δ 7.34-7.21 (m, 10H), 7.16 (t,
3J (H,H) ) 8.0 Hz, 8H), 6.97 (tt, J (H,H) ) 7.4, 1.1 Hz, 4H),
6.82 (md, 3J (H,H) ) 8.6 Hz, 8H), 6.80 (s, 4H), 3.82 (s, 8H),
3.71 (s, 4H); 13C NMR (50 MHz, CDCl3, 25 °C) δ 157.0, 152.9,
137.7, 135.0, 133.1, 129.24, 129.19, 128.4, 127.3, 122.6, 120.5,
119.4, 115.7, 114.5, 61.9, 56.0; UV/vis (CH2Cl2) λmax, nm (ꢀ,
mol-1 dm3 cm-1) 453 (26 200), 429 (22 100), 381 (5200), 360
(3700), 298 (57 000), 259 (31 000); fluorescence (CH2Cl2) λmax
) 486 nm; MS (FD, 8 kV) 882 (M+). Anal. Calcd for C62H46N2O4
(883.06): C, 84.33; H, 5.25; N, 3.17. Found: C, 84.33; H, 5.26;
N, 3.07.
5,6,12,13-Tetr a (4-ter t-bu tylp h en oxy)-1,3,8,10-tetr a h y-
d r o-2,9-d iben zyl-2,9-d ia za d iben zo[cd ,lm ]p er ylen e (4b).
Prepared from perylene bisimide 3b (3.00 g, 2.58 mmol), AlCl3
(2.87 g, 20.0 mmol), LiAlH4 (0.78 g, 20.5 mmol), and THF (100
mL) in the same way as described for 4a : yield 1.55 g (60%);
Cl4N2O4 (640.4): C, 60.02; H, 3.46; N, 4.37. Found: C, 59.32;
H, 3.16; N, 3.99.
N,N′-Diben zyl-1,6,7,12-tetr a p h en oxyp er ylen e-3,4:9,10-
tetr a ca r boxylic Acid Bisim id e (3a ). Perylene bisimide 2a
(7.08 g, 10.0 mmol), phenol (4.70 g, 50.0 mmol), and K2CO3
(5.52 g, 40.0 mmol) were stirred under argon in NMP (150 mL)
at 130 °C for 16 h. The reaction mixture was poured into 1 N
HCl (500 mL) and stirred for 1 h. The precipitate was collected,
washed thoroughly with H2O and MeOH, and dried. Purifica-
(25) Sheldrick, G. M. SHELXS-97, Program for the Solution of
Crystal Structures, Go¨ttingen, 1997.
(26) Sheldrick, G. M. SHELXL-97, Program for the Refinement of
Crystal Structures, Go¨ttingen, 1997.
(27) Massa, W. Kristallstrukturbestimmung, 2nd ed.; Teubner:
Stuttgart, 1996.

3044 J . Org. Chem., Vol. 67, No. 9, 2002
Wu¨rthner et al.
mp 195 °C dec; 1H NMR (500 MHz, CDCl3, 25 °C, TMS) δ 7.34
(m, 4H), 7.30 (m, 4H), 7.24 (m, 2H), 7.14 (d, 3J (H,H) ) 9.0 Hz,
at 170 °C (5 h) in the same way as described for 5a : yield
1
0.27 g (56%); mp 285 °C; H NMR (500 MHz, CDCl3, 25 °C,
3
3
8H), 6.80 (s, 4H), 6.72 (d, J (H,H) ) 9.0 Hz, 8H), 3.84 (s, 8H),
TMS) δ 9.18 (s, 4H), 7.48 (s, 4H), 7.29 (d, J (H,H) ) 8.4 Hz,
3.72 (s, 4H), 1.27 (s, 36H); UV/vis (CH2Cl2) λmax, nm (ꢀ, mol-1
dm3 cm-1) 458 (25 400), 434 (21 500), 363 (4300), 304 (53 400),
264 (37 000); fluorescence (CH2Cl2) λmax 494 nm; MS (MALDI-
TOF, dithranol) 1106.8 (M+). Anal. Calcd for C78H78N2O4
(1107.5): C, 84.59; H, 7.10; N, 2.53. Found: C, 84.56; H, 7.24;
N, 2.46.
8H), 6.99 (d, 3J (H,H) ) 8.4 Hz, 8H), 1.33 (s, 36H); UV/vis (CH2-
Cl2) λmax, nm (ꢀ, mol-1 dm3 cm-1) 498 (61 200), 466 (35 800),
320 (23 600), 271 (49 900); fluorescence (CH2Cl2) λmax ) 515,
547 nm; fluorescence quantum yield (CHCl3) ΦF ) 0.75; HR-
MS (EI) calcd m/z for C64H60N2O4 920.4554, found 920.4554.
Anal. Calcd for C64H60N2O4‚0.5H2O (930.2): C, 82.64; H, 6.61;
N, 3.01. Found: C, 82.61; H, 6.58; N, 3.02.
5,6,12,13-Tetr aph en oxy-1,3,8,10-tetr ah ydr o-2,9-dibu tyl-
2,9-d ia za d ib en zo[cd ,lm ]p er ylen e (4c). Prepared from
perylene bisimide 3c (3.48 g, 4.0 mmol), AlCl3 (1.26 g, 9.4
mmol), LiAlH4 (1.07 g, 28.3 mmol), and THF (30 mL) in the
same way as described for 4a , but MPLC was carried out with
toluene/ethyl acetate (7:3) as eluent: yield 1.6 g (50%); mp 147
5,6,12,13-Tetr a p h en oxy-2,9-d ibu tyl-2,9-d ia za d iben zo-
[cd ,lm ]p er ylen iu m Bis(tetr a flu or obor a te) (6). A mixture
of 5,6,12,13-tetraphenoxy-1,3,8,10-tetrahydro-2,9-dibutyl-2,9-
diazadibenzo[cd,lm]perylene 4c (0.41 g, 0.5 mmol) and Hg-
(OAc)2 (0.64 g, 2.0 mmol) in acetic acid (20 mL) was stirred
under reflux for 1.5 h. The mixture was cooled to room
temperature and filtered, and H2O (15 mL) and HBF4 (1 mL
of a 50% aqueous solution) were added to give a brown
precipitate that was separated and washed with a small
amount of H2O/MeOH (1:1). After drying, the crude product
was purified by column chromatography on silica gel (CH2-
Cl2/MeOH 9:1) and recrystallized from methanol/diethyl ether
to give an orange crystalline solid: yield 0.25 g (51%); mp 272-
1
°C; H NMR (200 MHz, CDCl3, 25 °C, TMS) δ 7.16 (m, 8H),
6.96 (m, 4H), 6.84-6.82 (m, 12H), 3.79 (s, 8H), 2.52 (t, 4H),
1.55 (m, 4H), 1.32 (m, 4H), 0.89 (t, 6H); UV/vis (CH2Cl2) λmax
,
nm (ꢀ, mol-1 dm3 cm-1) 452 (24 800), 430 (20 600), 362 (3700),
300 (55 500), 258 (30 600); MS (MALDI-TOF, dithranol) 814.4
(M+). Anal. Calcd for C56H50N2O4 (815.0): C, 82.53; H, 6.18;
N, 3.44. Found: C, 82.40; H, 6.30; N, 3.40.
5,6,12,13-T e t r a p h e n o x y -2,9-d ia za d ib e n zo [cd ,l m ]-
p er ylen e (5a ). A mixture of 4a (2.65 g, 3 mmol) and 0.32 g
Pd/C (10% Pd) was stirred under argon in diphenyl ether (150
mL) for 6 h at 170 °C. After cooling, the mixture was filtered
over Celite/silica gel (each ca. 5 cm) and diphenyl ether was
eluted with CH2Cl2. The product was eluted with an increasing
amount of methanol, and the solvent was evaporated. After
MPLC chromatography on Si60 (CH2Cl2/MeOH 97:3), 3 was
isolated as a bright red solid: yield 1.00 g (48%); mp 273 °C;
1H NMR (500 MHz, CDCl3, 25 °C, TMS) δ 9.21 (s, 4H), 7.52
(s, 4H), 7.34 (t, 3J (H,H) ) 7.6 Hz, 8H), 7.18 (m, 4H), 7.13 (md,
3J (H,H) ) 7.6 Hz, 8H); 13C NMR (126 MHz, CDCl3, 25 °C) δ
156.6, 155.8, 143.3, 129.9, 126.8, 125.8, 124.4, 120.8, 120.2,
1
275 °C dec; H NMR (500 MHz, acetone-d6, 25 °C, δ ) 2.04
ppm) δ 9.92 (s, 4H), 8.03 (s, 4H), 7.50 (t, 3J (H,H) ) 7.9 Hz,
8H), 7.35 (t, 3J (H,H) ) 7.5 Hz, 4H), 7.30 (d, 3J (H,H) ) 7.8 Hz,
8H), 5.18 (t, 3J (H,H) ) 7.3 Hz, 4H), 2.29 (m, 4H), 1.50 (m, 4H),
3
0.96 (t, J (H,H) ) 7.3 Hz, 6H); 13C NMR (126 MHz, acetone-
d6, 25 °C) δ 160.0, 155.5, 137.5, 131.3, 130.0, 127.1, 126.7,
123.1, 121.87, 121.83, 108.7, 63.7, 34.4, 20.0, 13.7; UV/vis (CH2-
Cl2) λmax, nm (ꢀ, mol-1 dm3 cm-1) 502 (55 000), 469 (35 200),
367 (15 500), 335 (22 300), 301 (64 700), 260 (51 800); fluores-
cence (CH2Cl2) λmax ) 532, 574 nm; fluorescence quantum yield
(CHCl3) ΦF ) 0.50. Anal. Calcd for C56H46N2O4B2F8 (984.60):
C, 68.31; H, 4.71; N, 2.85. Found: C, 68.23; H, 4.71; N, 2.81.
108.14, 108.13; UV/vis (CH2Cl2) λmax, nm (ꢀ, mol-1 dm3 cm-1
)
496 (62 300), 465 (34 900), 307 (22 500), 294 (21 800), 270
(47 000); fluorescence (CH2Cl2) λmax ) 511, 544 nm; fluores-
cence quantum yield (CHCl3) ΦF ) 0.75; MS (EI) 696 (M+).
Anal. Calcd for C48H28N2O4 (696.76): C, 82.74; H, 4.05; N, 4.02.
Found: C, 82.41; H, 3.95; N, 4.09.
5,6,12,13-Tetr a (4-ter t-bu tylp h en oxy)-2,9-d ia za d iben zo-
[cd ,lm ]p er ylen e (5b). Prepared from 4b (0.46 g, 0.42 mmol),
44 mg Pd/C (10% Pd), and diphenyl ether (20 mL) with stirring
Ack n ow led gm en t. We are indebted to the Deutsche
Forschungsgemeinschaft, the Fonds der Chemischen
Industrie, and the Ulmer Universita¨tsgesellschaft for
financial support and to BASF AG for the donation of
chemicals.
J O011133L