Visible-light photocatalytic aerobic oxidation of sulfides to sulfoxides with a perylene diimide photocatalyst

Article abstract of DOI:10.1039/c9ob00945k

Photosensitized oxygenation has been recognised as a modern method of incorporating oxygen into a substrate, as it offers environmentally benign alternatives to several conventional synthetic procedures. A metal-free aerobic selective sulfoxidation photos

Full text of DOI:10.1039/c9ob00945k

Organic &
Biomolecular Chemistry
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Visible-light photocatalytic aerobic oxidation of
sulfides to sulfoxides with a perylene diimide
photocatalyst†
Cite this: DOI: 10.1039/c9ob00945k
Received 25th April 2019,
Accepted 11th July 2019
Yueying Gao,‡ Huan Xu,‡ Shiwei Zhang, Yan Zhang, * Chunlei Tang and
Weizheng Fan*
DOI: 10.1039/c9ob00945k
rsc.li/obc
Photosensitized oxygenation has been recognised as a modern cost and wide availability, a metal-free photocatalytic system
method of incorporating oxygen into a substrate, as it offers envir- provides an environmentally friendly alternative synthetic
onmentally benign alternatives to several conventional synthetic route for selective photocatalytic oxidation under mild
procedures. A metal-free aerobic selective sulfoxidation photosen- conditions.
sitized by a perylene diimide photocatalyst has been developed.
Chemoselective transformation of sulfides to sulfoxides is
The reaction utilizes visible light as the driving force and molecular of great interest, as many sulfoxides are biologically active
9
,10
oxygen as the oxidant. The advantages of the developed method compounds often used as pharmaceuticals
(Fig. 1).
1
1
include high efficiency and selectivity, extremely simple operation Sulfoxidation is also attractive in organic synthesis, fossil
and work-up procedure, mild reaction conditions, and practical fuel desulfurization, industrial wastewater treatment, and
1
2
13
1
4
application in late-stage functionalization.
chemical warfare agent disposal.
Therefore, there is a
demand for green and mild methods of sulfide oxidation pro-
ducing sulfoxides chemoselectively, without overoxidation to
sulfones. Traditionally, this oxidation has been achieved under
metal catalysis using peroxides or peracids as the oxidants.
Oxidation is one of the most fascinating organic transform-
ations and has been extensively studied in the past few years.
1
Traditionally, toxic or hazardous oxidizing agents, such as
toxic metal oxides and peroxides, in stoichiometric amounts
However, the over-oxidation to sulfones and the safety issues
2
were usually used for these chemical transformations.
10,15
associated with handling peracids
are the main drawbacks
Therefore, a catalytic, environmentally-friendly, and economi-
cal oxidation process is always in demand. Photochemistry is a
powerful synthetic technique that can promote various func-
tional group transformations through the use of light as a
associated with its use in industrial processes. Photosensitized
oxidation of sulfides is one promising way to sulfide–sulfoxide
transformations, as molecular oxygen is the terminal oxidizing
16–18
agent.
Several sensitizers were investigated for the photo-
3
4
green and traceless reagent. Visible-light photocatalysis has
become a prominent sector of synthetic methodology in the
oxidation of sulphides, involving organic molecules
16,18,19
20
17,21
(
Fig. 2),
inorganic materials or metal complexes.
5
last several years as it offers environmentally benign alterna-
tives to several conventional synthetic procedures.
However, most of them produce substantial amounts of by-
products, especially sulfones and aldehydes, as a result of over-
oxidation or competitive carbon oxidation, respectively.
Furthermore, some catalysts are unstable, which makes their
use in industrial processes difficult. For these reasons, a more
6
Consequently, photocatalysis has been recognised to comply
7
with the concepts of the Twelve Principles of Green Chemistry.
Photosensitized oxygenation has been recognised as a modern
method of incorporating oxygen into
a
substrate.
Photooxygenation is based on the activation of molecular
oxygen by the excited state of a sensitizer. It can occur either
by the singlet oxygen or by the electron transfer (ET) mecha-
8
nism. However, the employment of precious and toxic metals
significantly limits its practical application. Owing to its lower
School of Pharmaceutical Science, Jiangnan University, Wuxi 214122, P. R. China
†
Electronic supplementary information (ESI) available. See DOI: 10.1039/
c9ob00945k
These authors contributed equally to this work.
‡
Fig. 1 Biologically active sulfoxide derivatives.
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a
Table 1 Optimization of the oxidative reaction conditions
b
Entry
Catalyst
Solvent
Yield (%)
1
2
3
4
5
6
7
PDI-1
PDI-1
PDI-1
PDI-1
PDI-1
PDI-2
PDI-3
PDI-3
PDI-3
PDI-3
PDI-3
PDI-3
PDI-3
PDI-3
PDI-3
PDI-3
DMSO
DMF
5
18
32
20
40
Trace
91
82
71
66
78
68
72
20
Trace
Trace
3
CH CN
EtOH
Fig. 2 Visible-light organic photocatalysts for the photooxidation of
sulfides.
CH OH
3
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
3
OH
3
OH
3
OH
3
OH
3
OH
3
OH
3
OH
3
OH
3
OH
3
OH
3
OH
c
8
9
d
e
robust organic photocatalyst which is capable of oxidising a 10
f
g
h
1
1
1
1
2
3
large variety of sulfides is highly desirable.
In the same manner as the π-conjugated polyaromatic mole-
cules, perylene-3,4,9,10-tetracarboxyl disimides (PDIs) have 14
i
j
1
1
5
6
emerged as a class of fluorescent dye molecules because of
2
2
their tunable absorption and emission features. PDI deriva-
2
3
a
All reactions were carried out on a scale of 0.5 mmol of 1a in 2 mL of
tives find widespread applications in organic photovoltaics,
2
4
25
26
solvent under visible light at room temperature equipped with an
oxygen balloon. Yields of the isolated product. 1 mol% of PDI-3 as a
organic field-effect transistors, sensors, bioimaging, and
b
c
2
7
d
e
supramolecular assemblies
owing to their tunable
catalyst.f 0.5 mol% of PDI-3 as a catalyst. 5 W green LED as the light
g
h
source. 15 W CFL as the light source. Air as an oxidant. DTBP as an
π-backbone, which is further achieved either by aromatic core
extension or expansion. Despite these remarkable properties
of PDIs like photosensitization, there is little research on their
use as a visible-light-driven photocatalyst for synthetic trans-
i
j
oxidant. Without light. Under a nitrogen atmosphere.
2
8
formations, in particular, for selective aerobic oxidation. highest conversion (91%) and selectivity (100%) (entry 7). No
Herein, we report a photooxygenation of sulfides to sulfoxides, over-oxidation was observed. Another PDI derivative PDI-2 was
mediated by visible light with PDIs as the photocatalyst also examined as the photocatalyst in this reaction and a trace
(Scheme 1).
amount of product was obtained (entry 6) because of its extre-
We commenced our study by exploring the oxidation of mely weak solubility and UV–Vis absorption in MeOH (see the
thioanisole (1a) with 2 mol% of PDI-1 under visible light (5 W ESI†). A decrease in the amount of catalyst leads to a decrease
blue LED) for 10 h under an oxygen atmosphere at room temp- in yield (entries 8 and 9). The effect of the light source was
erature (Table 1). The reaction was first conducted in DMSO, also optimized and a blue LED performed as the most excel-
but the desired product was formed only in a negligible lent light source compared with green LED light and a CFL
amount (entry 1). Solvent optimization was performed and the (compact fluorescent lamp) (entries 10 and 11). Although
results indicated that solvents play an important role in the PDI-1 and PDI-3 exhibit the maximum absorption at 520 nm,
oxidation reactions (entries 2–5). The use of solvents such as three absorption peaks (450, 470, and 520 nm) exist in the
DMF, CH
3
CN and EtOH afforded products in low yields spectra. The higher yield obtained with a blue LED may be
entries 2–4), but CH OH delivered the highest conversion attributed to the wide absorption range of PDI-3. Air and DTBP
40%) after 10 h at room temperature (entry 5). Next, screening were also tested as the oxidants and lower yields were obtained
(
(
3
experiments were conducted to determine the effect of photo- compared with O (entries 12 and 13). The control experiments
2
sensitizer PDIs with different substituents on amides showed that no reaction proceeded in the absence of either
(
entries 6 and 7). PDI-3 with diisopropyl on the benzyl ring, PDI-3 (entry 14), light (entry 15) or even O (entry 16).
2
which has better solubility in CH
3
OH than PDI-1, gave the
Having established optimal reaction conditions, we investi-
gated the substrate scope of this procedure using 2 mol% of
PDI-3 as the catalyst under an oxygen atmosphere at room
temperature and by photoirradiation with a 5 W blue LED
(
(
(
Table 2). The results demonstrate that alkyl aryl thioethers
1a–1i), dialkyl thioethers (1j–1k) and diphenyl thioethers
1l–1r) almost uniformly afforded good yields and selectivity.
Substituted thioanisoles containing electron-donating or elec-
tron-withdrawing groups at the aryl moiety (1a–1e) were all oxi-
dized, but for the electron-deficient aryl groups, longer reac-
tion times were needed to obtain high conversions (1c–1e).
Scheme 1 PDIs as the photocatalysts for the oxygenation of sulfides to
sulfoxides.
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a
Table 2 PDI-catalyzed selective photooxidation of sulfides
Additionally, the Cl and Br groups were well tolerated in this
reaction (1c and 1d), providing the possibility for further
functionalization. Moreover, sterically hindered ortho-substi-
tuted thioanisole 1b was oxidised to sulfoxide 2b, albeit with
longer times and lower yield. The oxidation of sulfides con-
taining other alkyl groups, instead of a methyl group, was also
possible (1f–1i). Ethyl, cyclopropyl, allyl or benzyl sulfides were
also oxidized in good yields, without the detection of benzal-
dehydes, sulfones or unidentified by-products, as was found
with other catalytic systems. Compared to aryl alkyl thioethers,
the rate of dialkyl thioether sulfoxidation was generally faster
b
Entry
1
Substrate
Product
Time (h)
16
Yield (%)
91
2
3
4
14
14
14
68
(
1j–1k). Dialkyl sulphides were oxidized to sulfoxides in high
yields under these reaction conditions. Diphenyl thioethers
1l–1r) showed a slow reaction, possibly due to the low electron
82
85
(
density on the sulfur atom.
The photostability of PDI-3 under these reaction conditions
2
9
was also investigated. UV-Visible spectra of the reaction
mixture at the beginning and during the course of the reaction
were collected to confirm the stability of the photocatalytic
system (see the ESI†). To demonstrate that the photocatalytic
selective oxidation of sulfides is practical and scalable, the
gram-scale reactions were carried out (Scheme 2). Comparable
yields were obtained, thus providing a possibility for the large-
scale synthesis of sulfoxides in a sustainable and environmen-
tally friendly manner.
5
16
79
6
7
8
9
12
11
12
10
89
75
79
92
Lastly, to demonstrate the synthetic utility of this photo-
catalytic methodology, late-stage functionalization of sulfide
compounds was performed (Scheme 3). Treatment of sulfide 3
with O under the standard reaction conditions afforded the
2
corresponding sulfoxide derivative, which shows important
3
0
bioactivities as a potent CDK2 inhibitor.
Since the above experiments indicated that oxygen (O2),
photoirradiation, and PDI as the oxidation catalyst are all
essential for the photocatalytic oxidative reactions with high
activity and selectivity, it motivated us to gain insight into the
mechanistic details of the reactions. The time profiles of the
photooxidation (Fig. S1, see the ESI†) revealed that the reac-
tions were totally inhibited in the absence of light. These
1
0
1
8
8
95
90
1
1
2
12
78
1
1
1
3
4
5
12
12
12
81
77
87
Scheme 2 Gram-scale reactions for the PDI-catalyzed selective
oxidation.
1
1
6
7
8
12
12
12
83
72
70
1
a
All reactions were carried out using 1 (0.5 mmol) and 2 mol% of catalyst
Scheme 3 Late-stage functionalization of sulfides for the synthesis of
bioactive sulfoxide 4.
b
3
PDI-3 in 2 mL of CH OH under blue LED irradiation. Isolated yields.
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results indicated that continuous irradiation with visible light
is essential for the photocatalytic transformations. Two main
mechanisms for the visible-light photocatalytic oxidation of
1
8,31
sulfides have been proposed in the literature:
singlet
oxygen oxidation through an energy transfer and a radical
pathway through electron transfer. In order to gain further
insight into the mechanism, additional experiments were
carried out (Fig. 3). The addition of the radical inhibitors
TEMPO or 1,4-benzoquinone significantly inhibited the trans-
formation. Furthermore, the effect of DABCO (1,4-diazabicyclo
[2.2.2]-octane, a singlet oxygen scavenger) on the photo-
catalytic oxidative reactions was also studied. We found that
the photooxidative reaction of sulfides can also be significantly
Scheme 4 Proposed mechanism.
1
suppressed (Fig. 3a). It is well known that oxidations via O
2
1
6–18
can be accelerated using deuterated solvents.
We observed
the obvious change in the oxidation rate when MeOH or deute-
rated MeOH was used (Fig. 3b). We employed the ESR spin-
trapping technique (with DMPO) to probe the nature of the
reactive oxygen species generated during the reaction under
•
−
visible irradiation and characteristic peaks of DMPO-O
and
2
1
32
DMPO- O were obviously observed (Fig. 3c). Therefore, we
2
•
−
1
propose that the presence of both O
2
2
and O is responsible
for the photooxidation reaction of sulfides.
The reaction mechanism of the PDI-catalyzed selective oxi-
dative reactions is summarized in Scheme 4. Both electron
transfer (ET) and energy transfer (EnT) may exist in the photo-
catalytic oxidation of sulfides to sulfoxides. By employing the
EnT process, sulfide radical cation 5 was generated, which can
be oxidized to sulfoxide 2. Upon employing the energy
1
transfer pathway, O2 was produced using PDI. Then,
singlet oxygen could grab one electron from the lone pair
of electrons of sulfide 1, forming radical cation 6, which
could react with another molecule of 1 to afford 2 as the
product.
Conclusions
In summary, we have documented PDI as a cost-effective and
environmentally friendly photocatalyst by activating molecular
oxygen (O ) for the selective oxidation of sulfides to sulfoxides
2
with high efficiency under mild conditions. The catalyst is able
to oxidize sulfides containing different functional groups with
excellent yields, and without over-oxidation to sulfones or the
formation of other by-products. The method meets the criteria
for environmentally friendly procedures and agrees with the
important concepts of green chemistry with the use of in-
expensive household light. Meanwhile, this new class of photo-
redox catalyst may be used for other chemical reactions, await-
ing further investigation.
Conflicts of interest
Fig. 3 Control experiments.
There are no conflicts to declare.
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P. Anastas and J. Warner, Principles of green chemistry,
New York, 1998.
Acknowledgements
We thank the National Natural Science Foundation of China
8 C. S. Foote, Photochem. Photobiol., 1991, 54, 659.
(
No. 21302067) and the National Natural Science Foundation
9 (a) P. Metzner and A. Thuillier, Sulfur reagents in organic
synthesis, Elsevier, 2013; N. S. Simpkins, Sulfones in Organic
Synthesis, Pergamon Press, Oxford, 1993(b) G. A. Doherty,
T. Kamenecka, E. McCauley, G. Van Riper, R. A. Mumford,
S. Tong and W. K. Hagmann, Bioorg. Med. Chem. Lett.,
of Jiangsu Province (No. BK20130120) for financial support.
Notes and references
2002, 12, 729–731; (c) R. A. Hartz, A. G. Arvanitis,
1
(a) C. K. Hill and J. F. Hartwig, Nat. Chem., 2017, 9, 1213–
221; (b) A. R. Kulkarni, Z. J. Zhao, S. Siahrostami,
J. K. Norskov and F. Studt, Catal. Sci. Technol., 2018, 8, 114–
23; (c) X. J. Lang, J. C. Zhao and X. D. Chen, Angew. Chem.,
Int. Ed., 2016, 55, 4697–4700; (d) A. E. Wendlandt and
S. S. Stahl, Angew. Chem., Int. Ed., 2015, 54, 14638–14658;
C. Arnold, J. P. Rescinito, K. L. Hung, G. Zhang, H. Wong,
D. R. Langley, P. J. Gilligan and G. L. Trainor, Bioorg. Med.
Chem. Lett., 2006, 16, 934–937; (d) M. Artico, R. Silvestri,
S. Massa, A. G. Loi, S. Corrias, G. Piras and P. LaColla,
J. Med. Chem., 1996, 39, 522–530; (e) M. Artico, R. Silvestri,
E. Pagnozzi, B. Bruno, E. Novellino, G. Greco, S. Massa,
A. Ettorre, A. G. Loi, F. Scintu and P. La Colla, J. Med.
Chem., 2000, 43, 1886–1891; (f) I. Fernandez and N. Khiar,
Chem. Rev., 2003, 103, 3651–3705.
1
1
(
e) S. L. Yang, L. Peng, P. P. Huang, X. S. Wang, Y. B. Sun,
C. Y. Cao and W. G. Song, Angew. Chem., Int. Ed., 2016, 55,
016–4020; (f) A. Company and M. Costas, Applied
4
Homogeneous Catalysis with Organometallic Compounds: A 10 J. Legros, J. R. Dehli and C. Bolm, Adv. Synth. Catal., 2005,
Comprehensive Handbook in Three Volumes, 2017, pp. 347, 19–31.
525–1540; (g) S. Caron, R. W. Dugger, S. G. Ruggeri, 11 (a) K. A. Stingl and S. B. Tsogoeva, Tetrahedron: Asymmetry,
1
J. A. Ragan and D. H. Ripin, Chem. Rev., 2006, 106, 2943–
2010, 21, 1055–1074; (b) H. Pellissier, Tetrahedron, 2006, 62,
5559–5601.
2
989.
2
(a) K. Chen, A. Eschenmoser and P. S. Baran, Angew. Chem., 12 (a) S. Otsuki, T. Nonaka, N. Takashima, W. H. Qian,
Int. Ed., 2009, 48, 9705–9708; (b) N. D. Litvinas,
B. H. Brodsky and J. Du Bois, Angew. Chem., Int. Ed., 2009,
A. Ishihara, T. Imai and T. Kabe, Energy Fuel, 2000, 14,
1232–1239; (b) F. M. Collins, A. R. Lucy and C. Sharp,
J. Mol. Catal., 1997, 117, 397–403.
4
8, 4513–4516; (c) X. Y. Huang and J. T. Groves, J. Biol.
Inorg. Chem., 2017, 22, 185–207; (d) L. Que and 13 M. Henze, P. Harremoes, J. la Cour Jansen and E. Arvin,
W. B. Tolman, Nature, 2008, 455, 333–340; (e) J. M. Howell,
K. B. Feng, J. R. Clark, L. J. Trzepkowski and M. C. White,
J. Am. Chem. Soc., 2015, 137, 14590–14593.
Wastewater treatment: biological and chemical processes,
Springer Science & Business Media, 2001.
14 Y. C. Yang, J. A. Baker and J. R. Ward, Chem. Rev., 1992, 92,
1729–1743.
3
4
5
D. Rackl, P. Kreitmeier and O. Reiser, Green Chem., 2016,
1
8, 214–219.
15 (a) K. P. Bryliakov and E. P. Talsi, Curr. Org. Chem., 2012,
16, 1215–1242; (b) Y. L. Hu, D. Fang and R. Xing, RSC Adv.,
2014, 4, 51140–51145.
C. G. S. Lima, T. D. Lima, M. Duarte, I. D. Jurberg and
M. W. Paixao, ACS Catal., 2016, 6, 1389–1407.
(a) C. K. Prier, D. A. Rankic and D. W. C. MacMillan, Chem. 16 (a) T. Nevesely, E. Svobodova, J. Chudoba, M. Sikorski and
Rev., 2013, 113, 5322–5363; (b) J. W. Tucker and
C. R. J. Stephenson, J. Org. Chem., 2012, 77, 1617–1622;
R. Cibulka, Adv. Synth. Catal., 2016, 358, 1654–1663;
(b) J. Dad’ova, E. Svobodova, M. Sikorski, B. Konig and
R. Cibulka, ChemCatChem, 2012, 4, 620–623; (c) X. Y. Gu,
X. Li, Y. H. Chai, Q. Yang, P. X. Li and Y. M. Yao, Green
Chem., 2013, 15, 357–361; (d) S. M. Bonesi, M. Fagnoni,
S. Monti and A. Albini, Photochem. Photobiol. Sci., 2004, 3,
489–493; (e) S. M. Bonesi, M. Fagnoni and A. Albini, J. Org.
Chem., 2004, 69, 928–935; (f) S. M. Bonesi, R. Torriani,
M. Mella and A. Albini, Eur. J. Org. Chem., 1999, 1723–1728;
(g) S. M. Bonesi, M. Mella, N. d’Alessandro, G. G. Aloisi,
M. Vanossi and A. Albini, J. Org. Chem., 1998, 63, 9946–
9955; (h) H. R. Memarian, I. Mohammadpoor-Baltork and
K. Bahrami, Bull. Korean Chem. Soc., 2006, 27, 106–110;
(i) W. L. Li, Z. G. Xie and X. B. Jing, Catal. Commun., 2011,
16, 94–97.
(
c) M. Reckenthaler and A. G. Griesbeck, Adv. Synth. Catal.,
013, 355, 2727–2744; (d) M. L. Marin, L. Santos-Juanes,
A. Arques, A. M. Amat and M. A. Miranda, Chem. Rev.,
012, 112, 1710–1750; (e) D. Ravelli, M. Fagnoni and
2
2
A. Albini, Chem. Soc. Rev., 2013, 42, 97–113; (f) D. P. Hari
and B. Konig, Chem. Commun., 2014, 50, 6688–6699;
(
1
g) S. Fukuzumi and K. Ohkubo, Org. Biomol. Chem., 2014,
2, 6059–6071; (h) D. A. Nicewicz and T. M. Nguyen, ACS
Catal., 2014, 4, 355–360; (i) S. P. Pitre, C. D. McTiernan and
J. C. Scaiano, Acc. Chem. Res., 2016, 49, 1320–1330;
(
j) N. A. Romero and D. A. Nicewicz, Chem. Rev., 2016, 116,
0075–10166.
(a) T. P. Yoon, M. A. Ischay and J. N. Du, Nat. Chem., 2010,
1
6
2
, 527–532; (b) D. Ravelli, D. Dondi, M. Fagnoni and 17 A. Casado-Sanchez, R. Gomez-Ballesteros, F. Tato,
A. Albini, Chem. Soc. Rev., 2009, 38, 1999–2011;
F. J. Soriano, G. Pascual-Coca, S. Cabrera and J. Aleman,
(
c) V. I. Parvulescu and H. Garcia, Catalysis, 2011, 23, 204–
Chem. Commun., 2016, 52, 9137–9140.
2
52; (d) D. Ravelli, S. Protti, M. Fagnoni and A. Albini, Curr. 18 (a) E. Baciocchi, T. Del Giacco, F. Elisei, M. F. Gerini,
Org. Chem., 2013, 17, 2366–2373.
M. Guerra, A. Lapi and P. Liberali, J. Am. Chem. Soc., 2003,
This journal is © The Royal Society of Chemistry 2019
Org. Biomol. Chem.

View Article Online
Communication
Organic & Biomolecular Chemistry
1
25, 16444–16454; (b) S. M. Bonesi, M. Fagnoni and 25 (a) L. Zang, Y. K. Che and J. S. Moore, Acc. Chem. Res.,
A. Albini, Eur. J. Org. Chem., 2008, 2612–2620; (c) E. Baciocchi,
C. Crescenzi and O. Lanzalunga, Tetrahedron, 1997, 53, 4469–
2008, 41, 1596–1608; (b) M. A. Kaloo, R. Mishra and
J. Sankar, J. Mater. Chem. C, 2015, 3, 1640–1644.
4478; (d) S. M. Bonesi, M. Fagnoni, S. Monti and A. Albini, 26 (a) K. Peneva, G. Mihov, F. Nolde, S. Rocha, J. Hotta,
Tetrahedron, 2006, 62, 10716–10723.
9 C. Ye, Y. Zhang, A. Ding, Y. Hu and H. Guo, Sci. Rep., 2018,
K. Braeckmans, J. Hofkens, H. Uji-I, A. Herrmann and
K. Mullen, Angew. Chem., Int. Ed., 2008, 47, 3372–3375;
(b) M. Davies, C. Jung, P. Wallis, T. Schnitzler, C. Li,
K. Mullen and C. Brauchle, ChemPhysChem, 2011, 12,
1588–1595; (c) M. M. Sun, K. Mullen and M. Z. Yin, Chem.
Soc. Rev., 2016, 45, 1513–1528.
1
8
, 2205.
0 (a) E. L. Clennan, W. H. Zhou and J. Chan, J. Org. Chem.,
002, 67, 9368–9378; (b) K. Suzuki, J. Jeong, K. Yamaguchi
and N. Mizuno, New J. Chem., 2016, 40, 1014–1021;
2
2
(c) X. J. Lang, W. H. Ma, C. C. Chen, H. W. Ji and J. C. Zhao, 27 F. Wurthner, C. R. Saha-Moller, B. Fimmel, S. Ogi,
Acc. Chem. Res., 2014, 47, 355–363; (d) J. A. Johnson, X. Zhang,
T. C. Reeson, Y. S. Chen and J. Zhang, J. Am. Chem. Soc., 2014,
P. Leowanawat and D. Schmidt, Chem. Rev., 2016, 116, 962–
1052.
136, 15881–15884; (e) S. Liu, M. Q. Yang, Z. R. Tang and 28 (a) I. Ghosh, T. Ghosh, J. I. Bardagi and B. Konig, Science,
Y. J. Xu, Nanoscale, 2014, 6, 7193–7198; (f) P. F. Zhang,
Y. Wang, H. R. Li and M. Antonietti, Green Chem., 2012, 14,
2014, 346, 725–728; (b) L. Zeng, T. Liu, C. He, D. Y. Shi,
F. L. Zhang and C. Y. Duan, J. Am. Chem. Soc., 2016, 138,
3958–3961; (c) C. Rosso, G. Filippini, P. G. Cozzi,
A. Gualandi and M. Prato, ChemPhotoChem, 2019, 3, 193–
197.
1
904–1908; (g) A. M. Khenkin and R. Neumann, Catal. Lett.,
000, 68, 109–111.
1 (a) S. Fujita, H. Sato, N. Kakegawa and A. Yamagishi,
2
2
2
2
2
J. Phys. Chem. B, 2006, 110, 2533–2540; (b) G. Bianchini, 29 (a) M. Marchini, A. Gualandi, L. Mengozzi, P. Franchi,
A. Scarso, G. La Sorella and G. Strukul, Chem. Commun.,
012, 48, 12082–12084.
M. Lucarini, P. G. Cozzi, V. Balzani and P. Ceroni, Phys.
Chem. Chem. Phys., 2018, 20, 8071–8076.
2
2 (a) F. Wurthner, Chem. Commun., 2004, 1564–1579; 30 X. X. Hu, H. Zhao, Y. Z. Wang, Z. Liu, B. N. Feng and
(b) M. R. Wasielewski, J. Org. Chem., 2006, 71, 5051–5066;
C. L. Tang, Bioorg. Med. Chem. Lett., 2018, 28, 3385–3390.
(c) R. Regar, R. Mishra, P. K. Mondal and J. Sankar, J. Org. 31 (a) S. M. Bonesi, I. Manet, M. Freccero, M. Fagnoni and
Chem., 2018, 83, 9547–9552.
3 (a) C. Li and H. Wonneberger, Adv. Mater., 2012, 24, 613–
A. Albini, Chem. – Eur. J., 2006, 12, 4844–4857; (b) J. Liang,
C. Gu, M. Kacher and C. S. Foote, J. Am. Chem. Soc., 1983,
105, 4717–4721; (c) T. Hikita, K. Tamaru, A. Yamagishi and
T. Iwamoto, Inorg. Chem., 1989, 28, 2221–2223;
(d) J. M. Zen, S. L. Liou, A. S. Kumar and M. S. Hsia, Angew.
Chem., Int. Ed., 2003, 42, 577–579.
6
1
36; (b) E. Kozma and M. Catellani, Dyes Pigm., 2013, 98,
60–179; (c) Z. T. Liu, Y. Wu, Q. Zhang and X. Gao, J. Mater.
Chem. A, 2016, 4, 17604–17622.
4 X. W. Zhan, A. Facchetti, S. Barlow, T. J. Marks,
M. A. Ratner, M. R. Wasielewski and S. R. Marder, Adv. 32 Z. H. Wang, W. H. Ma, C. C. Chen, H. W. Ji and J. C. Zhao,
Mater., 2011, 23, 268–284. Chem. Eng. J., 2011, 170, 353–362.
Org. Biomol. Chem.
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