APEX Strategy Represented by Diels–Alder Cycloadditions—New Opportunities for the Syntheses of Functionalised PAHs

Article abstract of DOI:10.1002/chem.202001327

Diels–Alder cycloaddition of various dienophiles to the bay region of polycyclic aromatic hydrocarbons (PAHs) is a particularly effective and useful tool for the modification of the structure of PAHs and thereby their final properties. The Diels–Alder cycloaddition belongs to the single-step annulative π-extension (APEX) reactions and represents the maximum in synthetic efficiency for the constructions of π-extended PAHs including functionalised ones, nanographenes, and π-extended fused heteroarenes. Herein we report new applications of the APEX strategy for the synthesis of derivatives of 1,2-diarylbenzo[ghi]perylene, 1,2-diarylbenzo[ghi]perylenebisimide and 1,2-disubstituted-benzo[j]coronene. Namely, the so far unknown cycloaddition of 1,2-diarylacetylenes into the perylene and perylenebisimide bay regions was used. 1,2-Disubstituted-benzo[j]coronenes were obtained via cycloaddition of benzyne into 1,2-diarylbenzo[ghi]perylenes by using a new highly effective system for benzyne generation and/or high pressure conditions. Moreover, we report an unprecedented Diels–Alder cycloaddition–cycloaromatisation domino-type reaction between 1,4-(9,9-dialkylfluoren-3-yl)-1,3-butadiynes and perylene. The obtained diaryl-substituted core-extended PAHs were characterised by DFT calculation as well as electrochemical and spectroscopic measurements.

Full text of DOI:10.1002/chem.202001327

Accepted Article
Accepted Article
Title: APEX strategy represented by Diels-Alder cycloadditions – new
opportunities for the syntheses of functionalised PAHs
Authors: Aneta Kurpanik, Marek Matussek, Grażyna Szafraniec-Gorol,
Michał Filapek, Piotr Lodowski, Beata Marcol-Szumilas,
Witold Ignasiak, Jan Grzegorz Małecki, Barbara Machura,
Magdalena Małecka, Witold Danikiewicz, Sebastian Pawlus,
and Stanisław Krompiec
This manuscript has been accepted after peer review and appears as an
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of the final Version of Record (VoR). This work is currently citable by
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published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
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content of this Accepted Article.
To be cited as: Chem. Eur. J. 10.1002/chem.202001327
Link to VoR: https://doi.org/10.1002/chem.202001327
01/2020

10.1002/chem.202001327
Chemistry - A European Journal
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APEX strategy represented by Diels-Alder cycloadditions – new
opportunities for the syntheses of functionalised PAHs
Aneta Kurpanik,[a] Marek Matussek,[a] Grażyna Szafraniec-Gorol,[a] Michał Filapek,[a] Piotr Lodowski,[a]
Beata Marcol-Szumilas,[a] Witold Ignasiak,[a] Jan Grzegorz Małecki,[a] Barbara Machura,[a] Magdalena
Małecka,[a] Witold Danikiewicz,[b] Sebastian Pawlus[c] and Stanisław Krompiec*[a]
[a]
Aneta Kurpanik, Dr. Marek Matussek, Dr. Grażyna Szafraniec-Gorol, Dr. Michał Filapek, Beata Marcol-Szumilas, Prof. Piotr Lodowski,
Witold Ignasiak, Prof. Barbara Machura, Magdalena Małecka, Prof. Sebastian Pawlus, Prof. Stanisław Krompiec*
Institute of Chemistry,
Faculty of Science and Technology
University of Silesia
Bankowa 14, 40-007 Katowice,
Poland
,
,
E-mail: stanislaw.krompiec@us.edu.pl
[b]
[c]
Prof. Witold Danikiewicz
Institute of Organic Chemistry,
Polish Academy of Sciences,
Kasprzaka 44/52, 01-224 Warsaw,
Poland
Prof. Sebastian Pawlus
August Chełkowski Institute of Physics & Silesian Centre for Education and Interdisciplinary Studies,
Faculty of Science and Technology,
University of Silesia,
75. Pułku Piechoty 1A 41-500 Chorzów,
Poland
Supporting information for this article is given via a link at the end of the document.
Abstract: Diels-Alder cycloaddition of various dienophiles to PAHs
bay region is particularly effective and useful tool for PAHs structure
and finally properties modification. It is due to the fact that Diels-
Alder cycloaddition belongs to single-step Annulative π-Extension
(APEX) reactions and represents the maximum in synthetic
efficiency for the constructions of π-extended PAHs including
functionalised ones, nanographenes, and π-extended fused
heteroarenes. Herein we report new applications of APEX strategy
for the synthesis of derivatives of 1,2-diarylbenzo[ghi]perylene, 1,2-
and constantly increasing importance in optoelectronic devices
such as solar cells[3], light-emitting diodes[4], field-effect
transistors FETs[5] and molecular electronics[6]. PAHs, not only
pure hydrocarbon but also heteroatom-doped π-scaffolds, are
precursors of extended carbon networks, and their carbon
skeletons (or carbon-heteroatom) can be seen as small pieces
of graphene[7]. As far as perylene is concerned, structural
modifications are realized in peri, ortho, bay and both ortho and
bay region positions, which can be functionalised selectively. As
for expansion and modification of perylene and other PAHs’
structures, cycloaddition to bay region is of particular
significance. So far, cycloaddition of various ethylenic
dienophiles, namely maleic anhydride[8], N-substituted
diarylbenzo[ghi]perylenebisimide
and
1,2-disubstituted-
benzo[j]coronene. Namely, so far unknown cycloaddition of 1,2-
diarylacetylenes into perylene and perylenebisimides bay region was
used. 1,2-Disubstituted-benzo[j]coronenes were obtained via
cycloaddition of benzyne into 1,2-diarylbenzo[ghi]perylenes using a
new highly effective system for benzyne generation and/or high
pressure conditions. Moreover, we report unprecedented Diels-Alder
cycloaddition-cycloaromatisation domino-type reaction between 1,4-
(9,9-dialkylfluoren-3-yl)-1,3-butadiynes and perylene. The obtained
diaryl-substituted-core-extended PAHs were characterized by DFT
calculation, electrochemical and spectroscopic measurements.
maleimides[9], alkyl acrylates and maleates[10]
diazenedicarboxylates[11]
benzo- and naphtho-1,4-
anthraquionones[12] fumarodinitrile[13]
N-substituted 1,2,4-
,
dialkyl
,
,
,
triazoline-3,5-diones[14] has been described. In the case of
cycloaddition of dipolarophiles with triple bond, cycloaddition of
acetylene (gaseous or masked)[15], acetylenedicarboxylates[13,16]
,
arynes, i.e. unsubstituted or substituted benzynes, naphthynes,
9,10-phenanthryne and higher polyacynes are known[17]
Herein we report new applications of APEX strategy for the
.
The Diels-Alder reaction is undoubtedly one of the most
fundamental and useful tools available to organic chemists for
the synthesis of structures with expected properties. One of the
types of this reaction is cycloaddition of various dienophiles into
PAHs (polyaromatic hydrocarbons and their functionalised
synthesis
of
1,2-diarylbenzo[ghi]perylene,
1,2-
diarylbenzo[ghi]perylenebisimide
and
1,2-disubstituted-
benzo[j]coronene derivatives. Namely, cycloaddition of 1,2-
diarylacetylenes into perylene and perylenebisimide derivatives
derivatives)
bay
region.
PAHs,
including
perylene,
bay
region,
and
cycloaddition
of
benzyne
into
benzoperylene, coronene, naphthoperylene, bisanthene and
other hydrocarbons which structures can be derived from
perylene and also their functionalised derivatives, attract
increasing attention in many areas of chemistry, material
science and finally in modern technology[1]. It is worth to mention
that Diels-Alder cycloaddition into perylene and its derivatives
bay region belongs to single-step annulative π-extension
(APEX) reactions and represents the maximum in synthetic
efficiency for the constructions of π-extended PAHs, including
functionalised ones, nanographenes, and π-extended fused
heteroarenes[2]. PAHs, particularly perylene, benzoperylene,
coronene derivatives, especially perylenebisimides, have great
diaryl(disubstituted)benzo[ghi]perylenes, unknown before, was
used. Moreover, unprecedented Diels-Alder cycloaddition-
cycloaromatisation domino type reaction between 1,4-(9,9-
dialkylfluoren-3-yl)-1,3-butadiynes and perylene was discovered.
Our research was started from DFT calculations using
B3LYP functional. Activation energies of cycloaddition of various
dienophiles
tetraaminoperylene,
R1–C≡C–R2 type to perylene, 3,4,9,10-
3,4,9,10-tetranitroperylene and
benzo[ghi]perylene bay region, leading to cycloadducts were
determined (Figure 1). For the first time in 2009, the
cycloaddition reaction into PAHs bay region became the object
1
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of theoretical research using the DFT method[15c]. Namely, Fort
et al. hypothesised that activation energies of cycloaddition of
maleic anhydride to bay regions of increasingly long PAHs
should decrease in the series phenanthrene – perylene –
bisanthene – tetrabenzocoronene, due to diminishing aromatic
the calculations also shown, that formation of  bonds between
two carbon atoms of acetylene motif in dienophiles (CAc) with
respective carbon atoms of bay region perylene (CPe) has
synchronous character. In first phase of reaction, both CAc atoms
attack the perylene simultaneously and in transition state (TS)
stabilization energies of the terminal “wing” benzene rings[15c]
.
CAcCPe distances for both pair of carbon atoms is the same. In
This hypothesis was supported by B3LYP/6-31G* calculations
and confirmed experimentally: maleic anhydride undergoes
cycloaddition to substituted bisanthene but not to perylene. The
elegant approach to benzannulation of bay areas of large
polyaromatic hydrocarbons, described by Fort and Scott[15b], was
discovered thanks to computational investigation of reactive
dienophiles for this cycloaddition: nitroethene, at B3LYP/6-31G*
level of theory, was predicted to be more reactive by four orders
of magnitude. In this case, the calculated Ea activation energy
for cycloaddition of nitroethene is lower by 8.8 kcal/mol in
relation to energy barrier for reaction with phenyl-vinyl sulfoxide.
It is worth to mention that calculations with the use of B3LYP
functional and 6-31G* basis set but without the dispersion
corrections leads to unsystematic errors, at the order of tens of
Figure 2 the calculated potential energy surface as a functions of
CAc–CPe distances is presented, for cycloaddition reaction of 1,2-
diphenylacetylene with perylene. As is visible on the figure,
minimum energy path from reactants to transition state proceed
along the diagonal of PES, so at each moment, formation of 
bonds between appropriate carbon atoms will have synchronous
course. For relaxation from TS to transition product the same
process character can be observed. For disubstituted acetylenes
presented in Figure 2, in transition state the new formed C–C
bonds have the same length if the R substituents in dienophile
are the same. In the case when
R are different, i.e.
PhC≡CCOOMe, calculated transition state geometry suggest
that to some extend C–C bond formation can be asynchronous
process. For mentioned-above dienophile, length difference
between two CAc–CPe bonds is about 0.47 Å.
kcal/mol[15d]
.
Figure 2. (a) Potential energy surface (PES) as a functions of CAc–CPe
distances for cycloaddition reaction of 1,2-diphenylacetylene with perylene.
(b) Vertical projection of PES in the contour representation.
Figure 1. Calculated energy barriers for transition state (ETS) in modeled
cycloaddition reactions of R1–C≡C–R2 into perylene, 3,4,9,10-tetraamino-,
3,4,9,10-tetranitroperylene and benzo[ghi]perylene bay region, obtained by the
The calculation results showed that the activation energy of the
cycloaddition of various R1C≡CR2 nucleophiles strongly depends
on R and is the lowest for R = CO2R' (28,4 kcal/mol when R' = H
and 30,0 kcal/mol, when R' = Me) and the highest for R = Ph
(42.8 kcal/mol). Due to this fact, it was decided to start our
examinations from attempts to improve the formerly described
results of cycloaddition of acetylenedicarboxylates into perylene
DFT/B3LYP/def2-TZVP method. Result with superscript
cycloaddition of acetylenedicarboxylic acid. Moreover, the results with
superscript and corresponds to the cycloaddition of acetylene into
3,4,9,10-tetraaminoperylene and 3,4,9,10-tetranitroperylene, respectively.
Additionally, results shown in the superscript and correspond to
a refers to the
b
c
d
e
cycloaddition of 1,3-butadiyne into perylene and diphenylacetylene into
benzo[ghi]perylene, respectively. Ar = N-methylphthaloimido-3-yl
bay
region.
In
2009
cycloaddition
of
diethyl
acetylenedicarboxylate into bay region of perylene (toluene
150 C, 3 days, 56% conversion, 25% isolated yield[15c] was
described. Our results proved to be fruitful since the perylene
conversion was quantitative and isolated yields were over 95% –
Scheme 1.
Our calculations showed that activation energy of
cycloaddition reaction of disubstituted acetylenes into perylene
and its derivatives bay regions, surprisingly, depends mainly on
the dienophile, not diene structure. It can be inferred, that the
role and electronic influence of substituents in the positions 3,4,9
and 10 is low. The summary of this findings is presented in
Figure 1.
The activation energies of the cycloaddition of acetylene
into
perylene,
3,4,9,10-tetraamino-
and
3,4,9,10-
tetranitroperylene proved to be similar, despite the strong donor
or strong acceptor character of NH2 and NO2 groups. On the
contrary, the activation energy of cycloaddition of 1,2-
diphenylacetylene into benzo[ghi]perylene (46.0 kcal/mol) is
considerably higher than for perylene (42.8 kcal/mol). In 1969
Zander published a work regarding the relative reactivity of
perylene and another polycyclic aromatic hydrocarbons based
on perylene core in cycloaddition reaction of maleic anhydride
into bay region. It was shown that benzoperylene is 220 times
Scheme 1. Cycloaddition of acetylene dicarboxylates into perylene bay region
(perylene/dienophile = 1/5; 100% perylene conversion, isolated yield 95% (R =
Me) and 96% (R = Et)).
In the next step, we aimed to obtain the product of ethyl
phenylpropiolate cycloaddition into perylene. It was rational
because the value of activation energy of the cycloaddition of
phenyl propiolate into perylene (36.3 kcal/mol) is situated
between acetylene (35.0 kcal/mol) and 1,2-diphenylacetylene
(42.8 kcal/mol) cycloaddition. However, instead of cycloaddition
into perylene, the creation of the dimerisation of ethyl propiolate
was observed (Scheme 2).
less reactive than perylene[18]
. The results of our DFT
calculations were crucial in planning the conditions of
cycloaddition reaction of various acetylenes (R1–C≡C–R2 type)
to perylene and its derivatives. From mechanistic point of view,
2
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Analogical results were reported by Fondjo et al. where the
dimer of phenylpropiolate (with 30% yield) was created in the
reaction of some 2-aminothiophene fused with coumarin motif
with ethyl phenylpropiolate, instead of expected anellation
phenylpropiolate was confirmed with the aid of an X-ray analysis
(sup. info.).
The reaction shown in Scheme 1 was repeated without
perylene and as a result naphthalene derivative was obtained
with high yield. Results of our calculations suggest that in the
first stage of this reaction [2 + 2] cycloaddition takes place.
product[19]
. The structure of dimerisation product of ethyl
Scheme 2. Dimerisation of ethyl phenylpropiolate into diethyl 1-phenyl-2,3-naphthalenedicarboxylate (Nph) (Q = CO2Et; 80% isolated yield).
Next, the obtained cyclobutadiene derivative is transformed in
several steps into naphthalene derivative. Importantly, the value
Such cycloadditions to PAHs bay region have not been
described, so far. The reaction conditions were established
thanks to the test reactions, i.e. cycloaddition of 1,2-
diphenylacetylene into perylene bay region (Table 1, sup. info).
of ETS
is more than 10 kcal/mol lower for [2 + 2]
+
ZPE
cycloaddition than for [4 + 2] cycloaddition. Due to this fact the
reaction takes place very quickly in 185 °C, similarly to the
The highest yield of pure product was obtained at 285 C, 72 h,
in vacuum conditions (< 0.1 Pa), using excess of melted
perylene. Reactions conducted in different conditions (air or
argon atmosphere, higher or lower temperature, in solvent)
were characterised by lower yields and larger amount and
number of side products. Structures of some of the obtained
benzoperylenes were confirmed via X-ray analysis (sup.
info.).The only limitation of the reactions shown in the Scheme 3
and Table S3 is thermal stability of 1,2-diarylacetylenes. All of
the above-mentioned dienophiles were stable in the
cycloaddition conditions, which was verified with DSC (see sup.
info.).
cycloaddition of acetylenedicarboxylate into perylene (ETS + ZPE
=
28.4 kcal/mol).
On the basis of the results of DFT calculations, we
successfully performed several cycloadditions of 1,2-
diarylacetylenes into perylene bay region (Scheme 3 and Figure
3).
Scheme 3. Cycloaddition of Ar–C≡C–Ar to perylene (perylene/dienophile = 10/1).
Figure 3. Cycloaddition of 1,2-diarylacetylenes into perylene bay region – list of obtained products (isolated yields in the parentheses).
3
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The results of our calculations shown in the Figure 1
encouraged us to verify whether the cycloaddition of 1,2-
diarylacetylenes to 3,4,9,10-tetrasubstituted perylene is really
possible. The model compound was N,N'-disubstituted
perylenebisimide due to its thermal stability and importance for
organic electronics. Moreover, it is common knowledge that
perylenebisimides undergo various APEX-type modifications.
The successfully performed cycloaddition reactions confirmed
conclusions resulting from our DFT calculations. Namely, four
new derivatives of N,N'-disubstituted benzo[ghi]perylenebisimide
with good yields were obtained – Scheme 4.
One should add that in cycloaddition of 1,2-
diarylacetylenes into perylene and perylenebisimides bay region
the creation of cycloaddition products to both bay regions was
not observed. This fact is strictly correlated with the results of
DFT calculations, which showed that the cycloaddition activation
energy of acetylene to benzo[ghi]perylene is higher than in the
case of perylene.
Scheme 4. Cycloaddition of 1,2-diarylacetylenes into N,N'-bis(2-ethelhexyl-
and 2,6-diisopropylphenyl)perylenebisimides bay region (diene/dienophile =
1/5).
Figure 4. Cycloaddition of 1,2-diarylacetylenes into perylenebisimides bay region – list of obtained products (isolated yields in the parentheses).
The possibility to perform cycloaddition of benzyne generated
from 2-trimethylsilylphenyl triflate to selected 1,2-
benzyne generation and various reaction conditions, including
reactions under high pressure was tested in the model
diaryl(disubstituted dimethoxycarbonyl)benzo[ghi]perylenes was
also verified, which allowed to obtain coronene derivatives – see
Scheme 5. Similarly to the previous cases, we started from the
determination of activation energy of cycloadduct creation. It
was discovered that the activation energy of benzyne
cycloaddition into benzoperylene (7.0 kcal/mol) is only slightly
higher than in the case of cycloaddition of benzyne into perylene
(6.0 kcal/mol). Therefore, coronene derivatives were easily
obtained (see Scheme 6). Moreover, we claimed that benzyne
cycloaddion to 1,2-di(methoxycarbonyl)benzo[ghi]perylene (see
also Scheme 1) proceed very smoothly.
cycloaddition
of
benzyne
into
perylene
and
1,2-
diphenylbenzo[ghi]perylene bay region (Table 2 in sup. info.).
We would like to emphasise the efficiency of
dicyanoethane-dimethoxyethane system and unprecedented
outcome of cycloaddition under high pressure. According to us,
highly increased efficiency of 1,2-dicyanoethane in comparison
to acetonitrile stems from the fact that Cs+ complex with 1,2-
dicyanoethane is much more stable than the one with
acetonitrile. The consequence of higher stability of the above-
mentioned complex is increased fluoride anion activity in the
substitution of OTf group. Importantly, reaction yields from the
Scheme 6 were very low (< 10%) when benzyne was generated
in the mixture of MeCN/THF. As far as cycloaddition under high
pressure (1.8 GPa) is concerned, quantitative conversion in the
test reactions was also reached, which is unprecedented for
such reactions. However, due to technical simplicity, coronenes
in the larger scale were prepared under atmospheric pressure.
Scheme 5. Synthesis of benzo[j]coronenes via cycloaddition of benzyne into
selected diarylbenzo[ghi]perylenes (R = aryl or –COOMe; diene/benzyne
precursor/CsF = 1/4/4; succinonitrile/1,2-dimethoxyethane = 1v/1v).
The DFT calculations results suggested that the
cycloaddition of 1,4-diaryl-1,3-butadiynes into perylene bay
region is possible, as well. It was verified for 1,4-bis(9,9'-
dibutylfluoren-3-yl)-1,3-butadiyne and 1,4-bis(9,9'-dioctylfluoren-
3-yl)-1,3-butadiyne – see Scheme 6. To our surprise, we
separated from the post-reaction mixture 6-((9,9-dibutyl- and
Benzyne was in situ generated from commercially available
precursor – 2-trimethylsilylphenyl trifluoromethanesulfonate –
and a new very effective system, i.e. cesium fluoride and 1,2-
dicyanoethane in 1,2-dimethoxyethane. Using succinonitrile and
1,2-dimethoxyethane instead of standard THF and MeCN was
crucial for reaching the quantitative conversion of 1,2-
diarylbenzo[ghi]perylenes and 1,2-bis(methoxycarbonyl)benzo-
[ghi]perylene. The efficiency of a wide range of systems of
9,9-dioctyl)fluoren-2-yl)-9,9-dibutyl-
[a]naphtho[ghi]perylenes instead of expected products of one
and
9,9-dioctylfluoren-
4
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Figure 5. Cycloaddition of benzyne into 1,2-diaryl- and 1,2-dimethoxycarbonylbenzo[ghi]perylenes bay region – list of obtained products (isolated yields in the
parentheses).
triple-bond cycloaddition. The mentioned isolated π-extended
As it can be seen in Scheme 6, the first step of the domino-type
Diels-Alder cycloaddition-cycloaromatisation is Diels-Alder
cycloaddition of one carbon-carbon triple bond coming from
diyne, followed by cycloadduct aromatization via H2 elimination.
In the second step, cycloaromatisation of the benzo[ghi]perylene
derivatives takes place, which leads to further expansion of the
aromatic system. The semi-product is not detected, which
means that the second step is much faster than the first one. It
can be noticed that the semi-product has a structure of masked
dienyne, hence the second step is the cycloaromatisation of
dienyne. Thermal and catalytic cycloaromatisation of open and
masked conjugated dienynes is well-known and its importance
for the synthesis of both carbo- and heterocycles synthesis
cannot be overvalued [2d-g]. In this context, one should
PAHs turned out to be products of consecutive
cycloaromatisation of the semi-product presented in the Scheme
6 in the parenthesis. According to our best knowledge, the
domino-type reaction, namely Diels-Alder cycloaddition-
cycloaromatisation, presented in Scheme 7 is so far unknown.
This reaction is useful for the synthesis of π-extended PAHs
belonging to APEX strategy using Diels-Alder cycloaddition
followed by cycloaromatisation of cycloadduct.
particularly
enumerate
recently
described
double-
cycloaromatisation of 1,4-diaryl-1,3-butadiynes [2d-f], including
domino reaction [2d]. However, it is still cycloisomerisation
without Diels-Alder cycloaddition step. APEX strategy shown in
Scheme
6 is unknown combining of cycloaddition and
cycloisomerisation into a domino-type reactions leading to
unique and complex structures would be unavailable in any
other way.
For all of the obtained cycloaddition products and also for
unsubstituted
structures
(for
comparative
purposes),
DFT/B3LYP calculations were carried out. Additionally, optical
and electrochemical measurements were performed for almost
every structure – see sup. info. When it comes to the character,
location and E(HOMO-
Kohn-Sham orbitals for obtained
LUMO)
compound, the variability of the above-mentioned properties is
great. In the case of the derivatives of 1,2-diarylbenzoperylene
for BP4 the HOMO is localised on the aryl substituent but LUMO
on BP-core. For BP7 the orbitals localisation is reversed, it
means that HOMO orbital is situated on BP-core whereas LUMO
on Ar groups. For BP9 the HOMO is delocalised and involves
both BP-core and Ar groups, but LUMO is highly located on the
BP-core. For the remaining 1,2-diarylbenzo[ghi]perylenes the
HOMO and LUMO location is similar to the one for BP0
(unsubstituted benzo[ghi]perylene) and includes solely BP motif.
For obtained 1,2-diarylbenzo[ghi]perylenes E(HOMO- LUMO) ranges
from 2.89 to 3.51 eV. When it comes to PBI4 belonging to 1,2-
diaryl[ghi]benzoperylenebisimides its HOMO is placed on Ar
groups but LUMO on BPI-core. In case of the remaining PBI,
including BPI0 (unsubstituted one), the frontier orbitals are
localised only on BPI-core. The calculated E(HOMO- LUMO) for PBI
ranges
from
2.28
to
2.86
eV.
Also
for
1,2-
diaryl(dimethoxycarbonyl)benzo[j]coronenes
remarkable
influence of cycloaddition on frontier orbitals location and gap
energies was observed. For BC3 the HOMO is situated on BC-
core and LUMO on aryl groups. For BC4 the HOMO can be
found on BC-core and LUMO is delocalised on the entire
structure. The E(HOMO- LUMO) gap for BC ranges from 3.19 to 3.61
eV.
Scheme 6. Diels-Alder cycloaddition-cycloisomerisation domino-type reaction
between of 1,4-di(9,9-dibutyl- or 9,9-dioctylfluoren-3-yl)-1,3-butadiynes and
perylene (perylene/diyne
= 10/1). Synthesis of 6-((9,9-dibutyl- and 9,9-
The optical properties of the designed compounds in
CH2Cl2 were investigated with UV-Vis absorption and emission
dioctyl)fluoren-2-yl)-9,9-dibutyl- and 9,9-dioctylfluoren[a]naphtho[ghi]perylenes
(with 10 and 8% isolated yield, respectively).
5
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spectroscopy (Tables S5-S6 and Figures S43-S46 in ESI). For
all the compounds, the lowest energy absorption band exhibits
well-defined vibronic structure and its position is predominately
resulted in 100% diene conversion. According to our best
knowledge, it is the first such spectacular pressure effect in
aryne cycloaddition. Two 6-((9,9-dialkyl)fluoren-2-yl)-9,9-
dialkylfluoren[a]naphtho[ghi]perylenes were prepared via
unprecedented Diels-Alder cycloaddition-cycloaromatisation
domino type reaction between 1,4-diaryl-1,3-butadiynes and
perylene. DFT calculations, optical and electrochemical
measurements given for all the obtained cycloaddition products
confirm that APEX strategy (in this work represented by Diels-
Alder cycloaddition and cycloaddition-cycloaromatisation
domino-type reaction) is able to generate π-expanded structures
with broad spectrum of properties. All of the obtained derivatives
can be further modified, including core-expansion via
cycloaddition into the remaining bay region or/and via Scholl-
type dehydrocyclocondensation. Further works on the obtained
molecules, namely testing in OLED or solar cells technology, are
currently ongoing.
governed by core-expanded perylene unit.
bathochromic shift of the absorption
A
significant
of 1,2-
diarylbenzo[ghi]perylenebisimides (PBI1-PBI4) in relation to
other investigated systems is attributed to introduction of
bisimide fragments into benzo[ghi]perylene core (Figure S44).
Emission behaviour of the reported compounds is largely
affected by expanded perylene core, but the impact of attached
substituents can be also noticed (Figure S46). As illustrated for
PBI1–PBI4, BP4 and BP7, addition of bisimide fragments or
strong electron-donating triphenylamine induces dramatic
bathochromic shifts of the emission. For the vast majority of the
obtained compounds, the fluorescence spectra have well-
defined vibronic structures, typically for locally excited state in
extended -conjugated aryl systems. On the contrary, the
emission band of BP4 and BP7 becomes unstructured and
broad. Prominent red-shift accompanied with change of
emission profile from vibronically structured to broad
unstructured is indicative for CT nature of the emitting states in
BP4 and BP7. Significant enhanced fluorescence intensity was
revealed for 1,2-diarylbenzo[ghi]perylene-bisimides (66-79%).
An exception in this group was PBI4, with fluorescence
quantum yield of 6.3%. In series of BP1-BP9, the introduction of
triphenylamine moieties was found to be beneficial regarding
emission quantum yield (Table S6).
Acknowledgements
This work was supported by National Science Centre of Poland,
Projects No. 2016/21/B/ST5/00805 and 2019/33/N/ST4/00817.
Calculations have been carried out using resources provided by
Wroclaw Centre for Networking and Supercomputing (http://wcss.pl),
grant No. 18.
All of the obtained compounds were also investigated
electrochemically in their diluted CH2Cl2 solutions. By using
cyclic voltammetry one can easily estimate molecule’s HOMO
and LUMO energy level (or rather, ionization potentials and
electron affinities) and energy gaps, assuming the IP of
ferrocene equal’s -5.1 eV[20]. First, behaviour of BP1-BP9 and
FBPI1-FBPI2 compounds were evaluated. For each of above-
mentioned compounds oxidation (BP/BP+) is fully reversible
process with peak onsets strongly depending on substituent
nature. For example, compound possessing strongly π-donating
TPA (triphenyl amine) group, i.e. BP4 exhibit lowest Eox value
(0.31 V), while in the case of BP3 (with (p-trifluoro-
methyl)phenylene moiety) Eox is highest (0.82V). Only for BP9
electrochemical response is slightly different – oxidation occurs
exclusively at carbazole fragments. On the other hand, reduction
(BP/BP-) takes place below -2.14V and is located at
benzo[ghi]perylene core. The only exceptions are BP7 and BP8
for which reduction occurs at substituent’s imide moieties
(-1.82 V and -1.72 V, respectively). PBI’s series exhibit typical for
this type of compounds behaviour – i.e. two step, reversible
reduction: Ered1 (PBI/PBI-) and Ered2 (PBI-/PBI2-) an irreversible
oxidation. It is worth noting that in the case of PBI4 oxidation
occurs at carbazole moiety, as expected. Comparing BC1-BC4
compounds with their BP precursors one can easily observe that
extension of fused benzene rings lowering both Eox and Ered i.e.
oxidation is easier (due to the fact that created carbocations are
better stabilised) while reduction is harder.
Keywords: APEX • cycloaddition • cycloaromatisation • perylene •
PAHs
[1] a) Z. Sun, Q. Ye, C. Chi, J. Wu, Chem. Soc. Rev. 2012, 41,
7857–7889; b) J. Wu, W. Pisula, K. Müllen, Chem. Rev. 2007,
107, 718–747; c) M. Bendikov, F. Wudl, D. F. Perepichka,
Chem. Rev. 2004, 104, 4891–4946; d) J. Xiao, H. M. Duong, Y.
Liu,
W. Shi, L. Ji, G. Li, S. Li, X.-W. Liu, J. Ma, F. Wudl, Q. Zhang,
Angew. Chem., Int. Ed. 2012, 51, 6094–6098; e) P. -Y. Gu,
F. Zhou, J. Gao, G. Li, C. Wang, Q. -F. Xu, Q. Zhang, J. -M. Lu,
J. Am. Chem. Soc. 2013, 135, 14086–14089; f) U. H. F. Bunz,
Acc. Chem. Res. 2015, 48, 1676–1686; g) T. Weil, T. Vosch,
J. Hofkens, K. Peneva, K. Müllen, Angew. Chem., Int. Ed. 2010,
49, 9068–9093.
[2] a) O. T. Dyan, G. I. Borodkin, P. A. Zalkin, Eur. J. Org. Chem.
2019, 44, 7271–7306; b) D. M. Hitt, J. M. O'Connor, Chem. Rev.
2011, 111, 7904–7922; c) E. Aguilar, R. Sanz, M. Fernández-
Rodríguez, P. García-García, Chem. Rev., 2016, 116, 8256–
8311; d) V. Yang, R. Bam, V. J. Catalano, W. A. Chalifoux,
Angew. Chem., Int. Ed. 2018, 57, 14773–14777;
e) G. M. Paternò, Q. Chen, X. -Y. Wang, J. Liu, S. G. Motti,
A. Petrozza, X. Feng, G. Lanzani, K. Müllen, A. Narita,
F. Scotognella, Angew. Chem., Int. Ed. 2017, 56, 6753–6757;
f) H. Ito, Y. Segawa, K. Murakami, K. Itami, J. Am. Chem. Soc.
2018, 141, 3–10; g) A. Narita, X. -Y.Wang, X. Feng, K. Müllen,
Chem. Soc. Rev. 2015, 44, 6616–6643.
[3] M. Nakano, H. Mori, S. Shinamura, K. Takimiya, Chem. Mater.
In summary, using APEX strategy, nineteen new core-
2012, 24,190–198.
expanded
perylene
derivatives,
namely
nine
[4] K. Sawabe, M. Imakawa, M. Nakano, T. Yamao, S. Hotta,
Y. Iwasa, T. Takenobu, Adv. Mater. 2012, 24, 6141–6146.
[5] M. Más-Montoya, R. P.Ortiz, D. Curiel, A. Espinosa, M. Allain,
A. Facchetti, T. J. Marks, J. Mater. Chem. C 2013, 1, 1959–
1969.
[6] A. Dadvand, A. G. Moiseev, K. Sawabe, W. -H. Sun, B. Djukic,
I. Chung, T. Takenobu, Angew. Chem., Int. Ed. 2012, 51, 3837–
3841.
1,2-diarylbenzo[ghi]perylenes, four 1,2-diarylbenzo[ghi]perylene-
bisimides,
di(methoxycarbonyl)benzo[j]coronene
three
1,2-diarylbenzo[j]coronenes,
and two
1,2-
6-((9,9-
dialkyl)fluoren-2-yl)-9,9-dialkylfluoren[a]naphtho[ghi]perylenes
were successfully synthesized. 1,2-Diarylbenzo[ghi]perylenes
and 1,2-diarylbenzo[ghi]perylenebisimides were synthesized via
unprecedented Diels-Alder cycloaddition of 1,2-diarylacetylenes
into
1,2-Diarylbenzo[j]coronenes
benzo[j]coronene were obtained via benzyne cycloaddition into
1,2-diarylbenzo[ghi]perylenes or 1,2-di(methoxycarbonyl)-
benzo[ghi]perylene bay region using new highly active system
for benzyne generation, namely CsF NCCH2CH2CN
perylene
or
perylenebisimides
bay
region.
[7] a) H. Ito, K. Ozaki, K. Itami, Angew. Chem., Int. Ed. 2017, 56,
11144–11164; b) M. Stępień, E. Gońka, M. Żyła, N. Sprutta,
Chem. Rev. 2017, 117, 3479–3716.
[8] a) E. Clar, M. Zander, J. Chem. Soc. 1957, 4616–4619;
b) M. Yang, H. Zhou, Y. Li, Q. Zhang, J. Li, C. Zhang, C. Zhou,
C. Yu., J. Mater. Chem. C 2017, 5, 6572–6578.
and 1,2-di(methoxycarbonyl)-
+
+
[9] a) A. Ghosh, K.V. Rao, S. J. George, C. N. R. Rao, Chem. Eur.
J. 2010, 16, 2700–2704; b) S. Verma, M. K. Manna, S. K.
MeOCH2CH2OMe. High pressure conditions for benzyne
cycloaddition into perylene and 1,2-diarylbenzo[ghi]perylene
6
This article is protected by copyright. All rights reserved.

10.1002/chem.202001327
Chemistry - A European Journal
COMMUNICATION
Pandey, A. K. Das, S. Mukherjee, RSC Adv. 2014, 4, 62603–
62614.
[10] a) S. Hirayama, H. Sakai, Y. Araki, M. Tanaka, M. Imakawa,
T. Wada, T. Takenobu, T. Hasobe, Chem. Eur. J. 2014, 9081–
9093; b) W. Jiang, H. Quian, Y. Li, Z. Wang, J. Org. Chem.
2008, 73, 7369–7372.
[11] S. Tokita, K. Hiruta, K. Kitahara, H. Nishi, Synthesis 1982, 3,
229–231.
[12] J. Wu, J. Li, C. J. Jiao, K. –W. Huang, Chem. Eur. J.2011, 17,
14672–14680.
[13] H. Gopee, A. N. Cammidge, Chem. Eur. J. 2006, 12,
8609– 8613.
[14] C. Göltner, D. Pressner, K. Müllen, H. W. Spiess, Angew.
Chem., Int. Ed. Engl. 1993, 32, 1660–1662.
[15] a) R. Jasti, E. P. Jackson, T. J. Sisto, E. R. Darzi,Tetrahedron
2016, 72, 3754–3758; b) L. T. Scott, E. H. Fort, Angew. Chem.,
Int. Ed. 2010, 49, 6626–6628; c) E. H. Fort, P. M. Donovan,
L. T. Scott, J. Am. Chem. Soc. 2009, 131, 16006–16007; d) H.
Kruse, L. Goerigk, S. Grimme, J. Org. Chem. 2012, 77, 10824–
10834.
[16] L. T. Scott, E. H. Fort, Tetrahedron Lett. 2011, 52, 2051–2053.
[17] a) F. Xu, X. Xiao, T. R. Hoye, J. Am. Chem. Soc. 2017, 139,
8400–8403; b) F. Xu, X. Xiao, T. R. Hoye, Org. Lett. 2016, 18,
5636–5639; c) T. Kubo, H. Kurata, K. Matsumoto, Y. Hirao,
A. Konishi, Chem. Lett. 2013, 42, 592–594; d) X. Xiao, T. R.
Hoye, Nat. Chem. 2018, 10, 838–844; e) T. Nakamuro,
K. Kumazawa, H. Ito, K. Itami, Synlett. 2019, 30, 423–428;
f) N. Zink-Lorre, A. Doncel-Giménez, E. Font-Sanchis, J. Calbo,
Á. Sastre-Santos, E. Ortí, F. Fernández-Lázaro, Org. Chem.
Front. 2019, 6, 2860–2871; g) B. Schuler, S. Collazos,
L. Gross, G. Meyer, D. Pérez, E. Guitián, D. Peña, Angew.
Chem. Int. Ed., 2014, 53, 9004–9006.
[18] M. Zander, Liebigs Ann. Chem. 1969, 723, 27–33.
[19] E. S. Fondjo, D. Döpp, G. Henkel, Tetrahedron 2006, 62,
7121– 7131.
[20] P. Bujak, I. Kulszewicz-Bajer, M. Zagórska, V. Maurel,
I. Wielgus, A. Proń, Chem. Soc. Rev. 2013, 42, 8895–8999.
7
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Entry for the Table of Contents
It was shown, that APEX strategy represented by Diels-Alder cycloaddition of acetylenes and benzyne into perylenes bay region and
also by a new domino-type reaction is able to generate π-expanded structures with broad spectrum of properties. New, highly active
system for benzyne generation and high pressure conditions were unprecedentedly used. DFT calculations, optical and
electrochemical measurements were given for all the obtained products.
8
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