Synthesis of some new distyrylbenzene derivatives using immobilized Pd on an NHC-functionalized MIL-101(Cr) catalyst: photophysical property evaluation, DFT and TD-DFT calculations

Article abstract of DOI:10.1039/d1ra00457c

In this study the catalytic application of a heterogeneous Pd-catalyst system based on metal organic framework [Pd-NHC-MIL-101(Cr)] was investigated in the synthesis of distyrylbenzene derivatives using the Heck reaction. The Pd-NHC-MIL-101(Cr) catalyst s

Full text of DOI:10.1039/d1ra00457c

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Synthesis of some new distyrylbenzene derivatives
using immobilized Pd on an NHC-functionalized
MIL-101(Cr) catalyst: photophysical property
evaluation, DFT and TD-DFT calculations†
Cite this: RSC Adv., 2021, 11, 12374
a
Esmaeil Niknam,a Ali Mahmoodi,b Farhad Panahi,
Maryam Heydari Dokoohaki,a
*
a
a
*
Amin Reza Zolghadr and Ali Khalafi-Nezhad
In this study the catalytic application of a heterogeneous Pd-catalyst system based on metal organic
framework [Pd–NHC–MIL-101(Cr)] was investigated in the synthesis of distyrylbenzene derivatives using
the Heck reaction. The Pd–NHC–MIL-101(Cr) catalyst showed high efficiency in the synthesis of these
p-conjugated materials and products were obtained in high yields with low Pd-contamination based on
ICP analysis. The photophysical behaviors for some of the synthesized distyrylbenzene derivatives were
evaluated. The DFT and TD-DFT methods were employed to determine the optimized molecular
geometry, band gap energy, and the electronic absorption and emission wavelengths of the new
synthesized donor–p–acceptor (D–p–A) molecules in the gas phase and in various solvents using the
chemical model B3LYP/6-31+G(d,p) level of theory.
Received 19th January 2021
Accepted 22nd March 2021
DOI: 10.1039/d1ra00457c
rsc.li/rsc-advances
In this work, in continuation of our program on the synthesis
of stilbene derivatives,45–50 a highly efficient heterogeneous
catalyst system [Pd–NHC–MIL-101(Cr)]51 was introduced to be
applied in the synthesis of stilbene derivatives using Mizoroki–
Heck coupling reaction.52–57 The Pd–NHC–MIL-101(Cr) catalyst
system showed remarkable catalytic activity in the Heck reac-
tion51 and in order to further show its utility in organic synthesis
we investigate its applicability in the synthesis of dis-
tyrylbenzenes (DSBs). The synthetic pathway toward synthesis
of [Pd–NHC–MIL-101(Cr)] catalyst system is shown in Scheme 1.
Introduction
The synthesis of uorescent compounds to be used in organic
light emitting diodes (OLEDs),1–5 solar cells,6,7 organic eld
effect transistors (OFETs),8,9 sensing,10–12 and uorescent
probes13–16 is highly considered. Stilbene compounds are
a
signicant class of uorescent organic p-conjugated
compounds, which are widely used in the above mentioned
applications.17–26 Due to the systematic relationship between the
uorescence properties of the uorescent materials and their
chemical structures, stilbenes are an interesting class of
compounds which permit us to simply ne tune the photo-
physical properties via available chemical modications.27–31 To
synthesize stilbenes, different organic methodologies such as
Wittig reaction,32–34 Horner–Wadsworth–Emmons reaction,35
catalytic aldehyde olenations,36 and Mizoroki–Heck reac-
tion37,38 have been developed. Palladium-catalyzed coupling
reactions are key tools in stilbene synthesis because they consist
of a family of cross coupling reactions, allowing diversity
oriented synthesize of stilbenes.39–42 Thus, Mizoroki–Heck
reaction has been extensively used in the synthesis of stilbene
compounds.43,44
Results and discussion
Catalytic activity evaluation of Pd–NHC–MIL-101(Cr) catalyst
in the synthesis of distyrylbenzenes (DSBs)
In order to show the catalytic applicability of [Pd–NHC–MIL-
101(Cr)] catalyst in the synthesis of DSBs and stilbenes,
a model reaction was selected and different conditions were
checked to obtain high yields of desired products (Table 1).
As shown in Table 1, using different ratios of starting
materials in the presence of Pd–NHC–MIL-101(Cr) catalyst, it is
possible to obtain both compounds 3a and 3a0 in high yields. In
order to synthesize DSBs in high yield, the ratio of aryl halide to
1,4-distylbenzene was selected 2.2 to 1 (Table 1, entry 4). Also,
the best yield for mono-substituted product was achieved using
1 : 2.2 ratios for 1a : 2a (Table 1, entry 3). No improvement in
the reaction yield was observed by increasing the catalyst
loading more than 1.5 mol% (Table 1, entries 5–8).58 Using Pd/C
as a traditional catalyst,59–62 3a0 was obtained in lower yield of
aDepartment of Chemistry, College of Sciences, Shiraz University, Shiraz 71454, Iran.
E-mail: panahi@shirazu.ac.ir; panahichem@ymail.com
bDepartment of Polymer Engineering and Color Technology, Amirkabir University of
Technology, Tehran, Iran
† Electronic supplementary information (ESI) available: Spectral data, copy of 1H
NMR and 13C NMR of synthesized compounds, and some photophysical data of
uorescence compounds. See DOI: 10.1039/d1ra00457c
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catalyst in the synthesis of this class of p-conjugated mate-
rials with low Pd-contamination which is very important in their
applications.
Next we checked the synthesis of DSB derivatives using the
reaction of 1,4-dibromobenzene and styrene (Table 2). The Pd–
NHC–MIL-101(Cr) catalyst can effectively catalyze this coupling
reaction and it is possible to control the reaction to obtain both
3a and 3a00 in high yields. The synthesis of 3a00 is important
because it can be used for the synthesis of unsymmetrical DSB
incorporating two different functional groups in the ends of pi-
conjugated system.50 Using 1.5 mol% of Pd–NHC–MIL-101(Cr)
catalyst and ratio of 1 : 2.2 for 4a : 5a, DSB 3a was obtained in
84% isolated yield (Table 2, entry 3). Employing the same
catalyst loading and reveres ratio of 4a : 5a (2.2 : 1), compound
3a00 was obtained in 86% (Table 2, entry 4). Again, in order to
check the homoselectivity of the Pd–NHC–MIL-101(Cr) catalyst
in mono-functionalization using Heck chemistry the reaction
was checked using a Pd/C catalyst. Using this catalyst system
compound 3a00 was obtained in lower yield of 63% (same
conditions and stoichiometry). This experiment also represents
the key role of MOF structure in homoselectivity (Table 2,
entries 5 & 6). The Pd content of the products in this reaction
was also evaluated using ICP analysis and it was observed that
the obtained product using Pd–NHC–MIL-101(Cr) catalyst has
only 3.1 ppm of Pd, while for the product obtained in the
Scheme
catalyst.
1 Synthetic rote to synthesize [Pd–NHC–MIL-101(Cr)]
Table 1 Optimization of the Pd–NHC–MIL-101(Cr)-catalyzed Heck presence of homogeneous is around 22 ppm. Accordingly, this
reaction between aryl halides and 1,4-distylbenzenea
heterogeneous Pd catalyst system based on MOF is efficient in
the synthesis of DSBs with low Pd-contamination.
Aer optimization of the reaction conditions, in order to
show the applicability of this catalyst system in synthesis of
stilbene and DSBs, some different derivatives were synthesized
and results are depicted in Fig. 1.
As shown in Fig. 1, both electron-withdrawing and electron-
donating groups on aryl rings worked well with this method-
ology. The synthesis of these DSBs is important. For example,
b
Entry
x
1a : 2a ratio
Yield 3ab
Yield 3a0
1
2
3
4
5
6
7
8
9
10
1.5
1.5
1.5
1.5
1.25
1.25
2.0
2.0
1.5
1.5
1 : 2
2 : 1
6
70
5
83 (77)
6
70
4
84
20
71
85 (79)
20
88 (81)
2
78 (71)
8
Table 2 Optimization of the Pd–NHC–MIL-101(Cr)-catalyzed Heck
1 : 2.2
2.2 : 1
1 : 2.2
2.2 : 1
1 : 2.2
2.2 : 1
1 : 2.2
2.2 : 1
reaction between 1,4-dibromobenzene and stylbenzenea
87 (78)
20
58c
18c
a
Reaction conditions: 1a (1.0 mmol), 2a (based on the ratio), Pd–NHC–
MIL-101(Cr) (x mol%), DMF (5 mL), K2CO3 (2.5 mmol), 110 ꢀC, 12 h.
b
Entry
4a : 5a ratio
Yield 3ab
Yield 3a00
b
c
NMR yield. The Pd/C was used as catalyst. The yields in
parentheses related to isolated yields.
1
2
3
4
5
6
1 : 2
2 : 1
1 : 2.2
2.2 : 1
1 : 2.2
2.2 : 1
82 (76)
4
84 (77)
2
69
21
12
80 (73)
8
58% (same conditions and stoichiometry), demonstrating
important role of MOF structure in homoselectivity63 to obtain
3a0 in high yield (Table 1, entries 9 & 10). Also, the ICP analysis
of the product using Pd–NHC–MIL-101(Cr) catalyst showed less
than 2 ppm of Pd while the amount of Pd-content for the
product obtained using Pd/C catalyst was around 16 ppm. This
experiment showed that the efficacy of this Pd MOF-based
86 (79)
19c
63c
a
Reaction conditions: 1a (1.0 mmol), 2a (based on the ratio), Pd–NHC–
MIL-101(Cr) (1.5 mol%), DMF (5 mL), K2CO3 (2.5 mmol), 110 ꢀC, 12 h.
b
c
NMR yield. The Pd/C was used as catalyst. The yields in
parentheses related to isolated yields.
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Fig. 2 Synthesis of diverse D–p–A DSBs using Pd–NHC–MIL-101(Cr)
catalyst.a,b aReaction conditions: 3a0 (1.0 mmol), aryl halide 7a–e (1.0
mmol), base (2.0 mmol), Pd–NHC–MIL-101(Cr) catalyst (12.0 mg,
1.5 mol%), DMF (5 mL), 12 h at 110 ꢀC. bIsolated yield.
Fig. 1 Synthesis of diverse symmetrical DSBs and vinyl-functionalized
stilbenes using Pd–NHC–MIL-101(Cr) catalyst. Reaction conditions for
compound (3a–e): 1,4-divinylbenzene (0.55 mmol), aryl halide (1.0
mmol), base (2.0 mmol), amount of catalyst 12.0 mg (1.5 mol%), solvent
(5 mL), 12 h at 110 ꢀC. Reaction conditions for compound (3a0, 3b0 and
3d0): 1,4-divinylbenzene (1.1 mmol), aryl halide (1.0 mmol), base (2.0
mmol), amount of catalyst 12.0 mg (1.5 mol%), solvent (5 mL), 12 h at
110 ꢀC. All yields correspond to the isolated product.
Photophysical properties investigation of compounds 8a–e
Aer synthesizing and characterization of D–p–A DSBs, their
photophysical properties were investigated and results are depic-
ted in Table 3 and Fig. 3. All of the distyrylbenzene derivatives
showed a broad absorption band between 328–355 nm corre-
sponding to the intramolecular charge transfer (ICT) transfer
between donor and acceptor moieties in the molecules. Solvent
compound 3b derivatives were used as an amine-sensitive dye
for detection of proteins.64 These stilbene derivatives were also
used for the preparation of polycyclic aromatic hydrocarbons
(PAHs) and nanographene.65 Synthesis of hydroxylated stilbenes
is important in biological application point of view and using
this catalyst system, compounds 3d and 3d0 was successfully
synthesized in high yields.66 Pyridine-based stilbenes are
important in the preparation of porous coordination
polymers.67
The catalytic applicability of Pd–NHC–MIL-101(Cr) catalyst
system was also investigated in the synthesis of unsymmetrical
DSBs under optimized conditions. First, some amine-
functionalized aryl bromides were synthesized using a Cu-
catalyzed N-arylation reaction based on a known procedure in
the literature (Scheme 2).68
Table 3 Photophysical data for DSB derivatives in different solvents
lab
lem
Stock shis
3
Solvent
(nm)
(nm)
(cmꢁ1
)
(L molꢁ1 cmꢁ1
)
E (eV)
8a]M
DMF
CHCl3
THF
Dioxane
Toluene
355
355
355
355
355
540
552
529
509
507
9650
96 836
73 757
94 671
122904
88 301
3.49
3.49
3.49
3.49
3.49
10 053
9265
8522
8445
8b]P
DMF
CHCl3
THF
Dioxane
Toluene
355
345
352
352
350
532
535
524
506
501
9372
10 293
9325
8646
8611
60 756
53 302
67 162
62 334
64 526
3.49
3.59
3.52
3.52
3.54
The Mizoroki–Heck coupling reaction between synthetic
amine-functionalized aryl halides (7a–e) and compound 3b0 in
the presence of Pd–NHC–MIL-101(Cr) catalyst afforded D–p–A
systems in high isolated yields (Fig. 2).
8c]Z
DMF
CHCl3
THF
Dioxane
Toluene
342
340
340
340
340
532
545
527
511
508
10 442
11 063
10 436
9842
52 370
65 654
69 341
56 285
65 293
3.62
3.65
3.65
3.65
3.65
9726
8d]I
DMF
CHCl3
THF
Dioxane
Toluene
330
330
330
328
330
533
557
530
504
496
11 541
12 349
11 435
10 646
10 141
97 190
80 833
87 939
98 910
85 460
3.75
3.75
3.75
3.78
3.75
8e]A
DMF
CHCl3
THF
Dioxane
Toluene
350
345
345
345
345
541
550
529
509
507
10 087
10 803
10 081
9339
45 461
39 392
49 873
53 013
55 189
3.54
3.59
3.59
3.59
3.59
Scheme 2 Synthesis of amine-functionalized aryl bromides using Cu-
catalyzed N-arylation reaction.a,b aReaction conditions: 1,4-dibro-
mobenzene (1.0 mmol), amine (1.0 mmol), base (2.0 mmol), CuI
catalyst (10.0 mol%), picolinic acid (PCA, 20 mol%), DMF (5 mL), 12 h at
110 ꢀC. bIsolated yield.
9261
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polarity had minimal effect on the absorption band of all 532, 532, 533, and 541 in DMF (most polarity) for compounds 8a to
compounds showing their low dipole moment at the ground state. 8e, respectively. As shown in Fig. 3, compound 8c showed a blue-
The compounds were found to be uorescence in all solvents with green uorescence under UV lamp in toluene and its uorescence
an emission maximum between 496–550 nm. The large stokes changed to green, yellow, and orange hue upon increasing solvent
shis with values between 8445–12 349 cmꢁ1 for the samples polarity. This trend was also observed for other distyrylbenzene
suggest that the uorescence could be due to intramolecular derivatives suggesting a strong positive solvatochromic effect for
charge transfer (ICT). The emission spectra experienced a red shi the compounds (see ESI†).
from 507, 501, 508, 496, and 507 in toluene (least polarity) to 540,
The stabilization of the excited state by more polar solvents
was the reason for the observed solvatochromism. It should be
noted that the more solvent dependency of emission spectra
compared to that of absorption spectra for all compounds could
be attributed to more ICT characteristic of the samples in their
excited state than that of their ground states.69–71
The pH sensitivity of D–p–A DSBs were also evaluated and
results are summarized in Table 4. As detailed in this table,
upon decreasing the pH from 7 to 3, no meaningful change was
observed in emission band of the samples. With further
decreasing of the pH from 3 to 1, a weak blue shi with values
between 15 to 25 nm was observed for the uorescent
compounds. The observed blue shi could be assigned to
diminishing of intramolecular charge transfer (ICT) when the
chromophores were protonated by TFA. Surprisingly, a strong
red shi with values between 55–83 nm was detected for the
compound 8c in strong acidic condition.
DFT and TD-DFT calculations
In order to further clarify the experimental results, the opti-
mized molecular structures of compounds 8a–e DSBs are
illustrated in Fig. 4 using density functional theory (DFT) at the
B3LYP level. In this work, the B3LYP-D3 and uB97XD functional
methods which include empirical dispersions were also
employed in calculations and their computed maximum
absorption wavelengths were found to be more deviated from
experimental results.
These DSBs are D–p–A molecules consisting of the same
electron withdrawing nitrobenzene moiety as well as different
electron donating centers (morpholine, piperidine, piperazine,
imidazole, and alanine), which are connected by p-conjugation
in the middle. To illustrate the electronic distribution around
molecular surface and also to probe the sites of electrophilic
attack (negative potential) and nucleophilic reaction (positive
potential) for investigated molecular systems, molecular elec-
trostatic potential (MEP) surfaces were obtained. It is clearly
seen in Fig. 4, in the MEP surface for the 8a–e derivatives,
oxygen atoms of nitro groups and the center conjugated moie-
ties through the p-bridge illustrate regions of negative electro-
static potential (electron-rich) while the hydrogen atoms carry
the most positive potentials.
Clear elucidation of electron density distribution on the
highest occupied molecular orbital (HOMO) and lowest unoc-
cupied molecular orbital (LUMO) of the compounds 8a–e
congurations were plotted in Fig. 5. The HOMO of the
compounds 8a–e is mainly located to the donor segments
whereas the LUMO is concentrated to the terminal nitro
substituent which further veried that the charge distribution
on such molecules is extremely inuenced by NO2.
Fig. 3 UV-Vis spectra (a) and emission spectra (b) of 8c at concen-
tration of 10ꢁ5 M in different solvents. The photographs of the
compound in different solutions [from left to right, toluene, dioxane,
tetrahydrofuran (THF), chloroform (CHCl3), and dimethylformamide
(DMF)] were taken under natural daylight simulator (D65) lamps (top
image), and irradiation of A-Class UV lamps (bottom image).
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Table 4 The pH-sensitivity behavior of synthetic D–p–A DSBs 8a–e
lem
lem
lem
lem
lem
lem
lem
Comp.
8a
(nm) pH ¼ 7
(nm) pH ¼ 6
(nm) pH ¼ 5
(nm) pH ¼ 4
(nm) pH ¼ 3
(nm) pH ¼ 2
(nm) pH ¼ 1
552
535
545
557
550
552
535
545
557
550
552
535
545
557
550
552
535
545
557
550
552
534
535
519
545
530
557
537
550
531
552
533
535
518
545
529
557
537
528
605
552
530
535
514
545
524
557
533
526
633
8b
8c
8d
8e
and listed in Table 6. For instance, the electronic absorption
band with the highest wavelength of 8c compound has been
determined at 395.1 nm in DMF, 394.5 nm in CHCl3, 394.6 nm
in THF, 392.3 nm in dioxane, and 393.3 nm in toluene solvent.
In line with experimental UV-Vis spectra, the lab of 8d
compound is less than others. The electronic absorption of 8a–e
derivatives essentially originates from HOMO ꢁ 1 / LUMO
transition. As obtained for 8a–e series, the experimental and
calculated maximum absorption values follow a similar trend
while some deviations (ꢂ9–11%) from the experimental values
are observed. This deviation could be expected from the bulk
Fig. 4 Optimized structures of 8a–e molecules at the B3LYP/6-
31+G(d,p) level in the gas phase and electrostatic potential maps. ESP
contours are color-coded from red (negative) to blue (positive).
Table 5 signies the difference between theoretical values of
HOMO–LUMO band gap energy for 8a–e DSBs in gas phase and
solvent media. The calculated electrochemical band gap ener-
gies of the 8a–e derivatives in gas phase are found in the range
of 2.41–2.85 eV. The band gap energies were estimated to be in
the order of 8b < 8e < 8a < 8c < 8d in gas phase. Overall, the band
gap of DSBs decreases in selected solvents of varying polarities.
As the electric permittivity of the solvents declines along the
series DMF (3 ¼ 37.22), THF (3 ¼ 7.43), CHCl3 (3 ¼ 4.71), toluene
(2.37), and dioxane (3 ¼ 2.21), the band gap energies of all DSBs
increase, respectively. The results clearly reveal that the
Fig.
5 DFT computed HOMO and LUMO diagrams of 8a–e
compounds at the B3LYP/6-31+G(d,p) level.
Table 5 The band gap energies (eV) obtained in gas phase and
different solvents for 8a–e compounds
Compound
Gas
8a
8b
8c
8d
8e
2.48
2.11
2.20
2.16
2.30
2.30
2.41
2.05
2.13
2.10
2.23
2.22
2.46
2.11
2.20
2.17
2.31
2.30
2.85
2.52
2.62
2.58
2.72
2.70
2.42
2.06
2.15
2.12
2.25
2.23
electron-donating ability of donor moieties in these compounds DMF
leads to the changing of band gap energy.
The absorption (lab) and emission (lem) wavelengths, the
oscillator strength, and main assignments of 8a–e molecules in
CHCl3
THF
Dioxane
Toluene
a variety of solvents were predicted from TD-DFT calculations
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Table
6 Theoretical electronic transition parameters, oscillator
methodology in high isolated yields. The photophysical prop-
erties of these uorescence compounds were investigated and
DFT calculations were accomplished to investigate the opti-
mized molecular geometry, band gap energy, and the electronic
absorption and emission wavelengths.
strengths and important contributions of the 8a–e compounds in the
solvent media (TD-B3LYP/6-31+G(d,p))
Solvent
lab (nm) Osi. stren. Major contributions
lem (nm)
8a
DMF
CHCl3
THF
Dioxane 393.5
Toluene 394.5
397.6
394.6
396.7
0.957
1.042
1.009
1.134
1.118
H ꢁ 1 / LUMO (84%) 514.1
Conflicts of interest
H ꢁ 1 / LUMO (78%) 486.8
H ꢁ 1 / LUMO (81%) 502.1
H ꢁ 1 / LUMO (68%) 463.1
H ꢁ 1 / LUMO (70%) 465.9
There are no conicts to declare.
Acknowledgements
8b
DMF
CHCl3
THF
Dioxane 392.2
Toluene 394.3
398.1
396.3
396.4
0.985
1.066
1.036
1.156
1.140
H ꢁ 1 / LUMO (85%) 502.7
H ꢁ 1 / LUMO (79%) 495.9
H ꢁ 1 / LUMO (82%) 505.6
H ꢁ 1 / LUMO (71%) 470.8
H ꢁ 1 / LUMO (72%) 474.0
Financial support from the research councils of Shiraz Univer-
sity is gratefully acknowledged.
Notes and references
8c
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DMF
CHCl3
THF
Dioxane 392.3
Toluene 393.3
395.1
394.5
394.6
0.505
0.670
0.780
0.519
0.628
H ꢁ 1 / LUMO (86%) 519.5
H ꢁ 1 / LUMO (75%) 490.5
H ꢁ 1 / LUMO (85%) 501.5
H ꢁ 1 / LUMO (64%) 479.5
H ꢁ 1 / LUMO (74%) 482.3
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DMF
CHCl3
THF
Dioxane 357.4
Toluene 358.0
361.6
359.6
360.2
0.891
0.506
0.521
0.585
0.589
H ꢁ 1 / LUMO (55%) 511.3
H ꢁ 1 / LUMO (52%) 487.2
H ꢁ 1 / LUMO (44%) 508.2
H ꢁ 1 / LUMO (69%) 442.6
H ꢁ 1 / LUMO (70%) 473.9
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8e
DMF
CHCl3
THF
Dioxane 391.9
Toluene 393.0
396.2
394.8
395.1
1.098
1.040
1.012
1.030
1.029
H ꢁ 1 / LUMO (77%) 503.5
H ꢁ 1 / LUMO (81%) 491.2
H ꢁ 1 / LUMO (85%) 501.3
H ꢁ 1 / LUMO (62%) 456.3
H ꢁ 1 / LUMO (72%) 467.8
´
´
´
´
´
8 P. Tisovsky, A. Gaplovsky, K. Gmucova, M. Novota, M. Pavuk
and M. Weis, Org. Electron., 2019, 68, 121–128.
´ ˆ
9 M. R. Koli, A. Labiod, S. Chakraborty, M. Kumar, P. Leveque,
G. Ulrich, N. Leclerc, D. Jacquemin and S. Mula,
ChemPhotoChem, 2020, 4, 729–741.
solvent effects in experimental conditions while the calculated
data are obtained by considering implicit solvent models.
´
10 N. De Acha, C. Elosua, J. M. Corres and F. J. Arregui, Sensors,
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11 J. Ma, Y. Wang, G. Liu, N. Xu and X. Wang, RSC Adv., 2020,
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Conclusions
In conclusion we have developed an efficient palladium catalyst 12 S. Tsumura, K. Ohira, K. Imato and Y. Ooyama, RSC Adv.,
system based on MOFs in the synthesis of a very important class 2020, 10, 33836–33843.
of uorescence compounds, DSBs, using Heck chemistry. Using 13 D. Aydin, Talanta, 2020, 210, 120615.
this synthetic methodology it is possible to synthesize different 14 L. Long, Y. Han, X. Yuan, S. Cao, W. Liu, Q. Chen, K. Wang
DSB derivatives in good to excellent yields. It seems that the
and Z. Han, Food Chem., 2020, 331, 127359.
MOF structure is effectively facilitate the Heck reaction between 15 H.-Y. Kwon, X. Liu, E. G. Choi, J. Y. Lee, S.-Y. Choi, J.-Y. Kim,
bis-alkenes or aryl halides homoselectivity in order to have
mono-functionalized products in good yields. Mono-
L. Wang, S.-J. Park, B. Kim, Y.-A. Lee, J.-J. Kim, N. Y. Kang
and Y.-T. Chang, Angew. Chem., Int. Ed., 2019, 58, 8426–8431.
functionalized products in the both forms of vinyl- and 16 W. Chen, T. Matsunaga, D. L. Neill, C. Yang, T. Akaike and
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possible to synthesis both symmetrical and unsymmetrical
R. Jeet, D. Goswami and A. Goel, J. Org. Chem., 2018, 83,
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DSBs in high yields. Some new D–p–A DSBs which are con- 18 H. Y. Chung, J. Oh, J.-H. Park, I. Cho, W. S. Yoon, J. E. Kwon,
taining different amino groups (D group) and nitro group (A
D. Kim and S. Y. Park, J. Phys. Chem. C, 2020, 124, 18502–
group) were synthesized successfully using this new synthetic
18512.
© 2021 The Author(s). Published by the Royal Society of Chemistry
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12380 | RSC Adv., 2021, 11, 12374–12380
© 2021 The Author(s). Published by the Royal Society of Chemistry