Organolithium-Mediated Postfunctionalization of Thiazolo[3,2- c][1,3,5,2]oxadiazaborinine Fluorescent Dyes

Article abstract of DOI:10.1021/acs.joc.0c00552

An effective method for transition-metal-free postfunctionalization of thiazolo[3,2-c][1,3,5,2]oxadiazaborinine dyes via direct lithiation of the 1,3-thiazole ring was developed. The reaction allows valuable regioselective C-H modification of these N,O-ch

Full text of DOI:10.1021/acs.joc.0c00552

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Article
Organolithium-Mediated Postfunctionalization of
Thiazolo[3,2-c][1,3,5,2]oxadiazaborinine Fluorescent Dyes
Mykhaylo A. Potopnyk, Dmytro Volyniuk, Roman Luboradzki, Magdalena
Ceborska, Iryna Hladka, Yan Danyliv, and Juozas Vidas Grazulevicius
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.0c00552 • Publication Date (Web): 09 Apr 2020
Downloaded from pubs.acs.org on April 9, 2020
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The Journal of Organic Chemistry
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Organolithium-Mediated Postfunctionalization of Thiazolo[3,2-
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c][1,3,5,2]oxadiazaborinine Fluorescent Dyes
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Mykhaylo A. Potopnyk,* Dmytro Volyniuk, Roman Luboradzki, Magdalena Ceborska, Iryna Hladka,
Yan Danyliv, and Juozas V. Grazulevicius
Supporting Information Placeholder
Me2N
Me2N
N
B
1. LDA, -78 C
N
B
S
S
H
E
2. electrophiles,
O
N
F
O
N
F
-78 C
R
R = H, Me, Ph
R
F
F
ABSTRACT: An effective method of transition-metal-free postfunctionalization of thiazolo[3,2-c][1,3,5,2]oxadiazaborinine dyes
via direct lithiation of the 1,3-thiazole ring was developed. The reaction allows valuable regioselective C-H modification of these
N,O-chelated organoboron chromophores incorporating different groups, including C-, Hal-, Si-, S-, Se-, Sn-substituents. As a result,
a library of novel fluorescent 1,3-thiazole-based organoboron complexes has been synthesized and characterized. The influence of
the donor/acceptor strength of the substituent E on the photophysical properties has been established. Compound with bulky lipophilic
3
substituent (SnBu ) exhibits relatively high solid-state photoluminescence quantum yield of 44%.
Usually, the oxadiazaborinine dyes have been synthesized by
complexation of boron trifluoride with amide of electron-poor
INTRODUCTION
2
1
21c,22
N,O-coordinating organoboron dyes are currently intensively
2-amino-N-heterocycles such as pyridine, pyrazine,
1
–4
pyridazine, 1,8-naphthyridine, or 1,3,4-thiadiazole.24 Our
conception is based on the incorporation of electron-rich
heterocyclic building block into the oxadiazaborinine structure
to increase the chemical stability of these complexes. Recently,
we have described a simple synthetic route to highly fluorescent
oxadiazaborinine dyes 1 based on electron-rich 1,3-thiazole
21c
23
investigated due to their light emissive properties. They have
been successfully used as emitters in organic light-emitting
1
2
diodes (OLEDs) and organic solid-state lasers (OSSLs). Other
N,O-coordinating organoboron dyes exhibit aggregation-
3
induced emission (AIE) properties and have found application
4
in biological imaging. Classical synthesis of organoboron
2
5
complexes is based on the preparation of the corresponding
ligands and following complexation with boron-containing
building blocks (Figure 1a),
benzo[d]thiazole analogs.
as well as to their
1
9b,26
agent (such as BF
3
·OEt
2 3 3 2 2
, BAlk , BAr , Ar BOH, Ar BOAlk,
5
Ar
2
BCl, etc.). Another way is postfuctionalization of
a) previous work
Me2N
Me2N
compounds based on the organoboron core. The modification
H2N
S
N
B
S
methods of N,N-coordinating organoboron dyes are developed
Cl
N
6
7
well, including nucleophilic substitution, aldol addition,
O
N
F
BF3
O
R
6
a,b,8
9
Knoevenagel condensation,
1,3-dipolar cycloaddition,
R
1
F
1
0
photocatalytic transformations, and transition metal catalytic
R = H (a), Me (b), Ph (c)
1
1
6c,12
6c
12c,13
reactions
(such as Suzuki,
Stille,
Negishi,
b) this work
14
15
16
Sonogashira, C-H arylation, C–H alkylation, oxidative
Me2N
Me2N
LDA-mediated
electrophilation
H
17
aromatic coupling ). Meanwhile, the postfunctionalization of
N
B
N
N,O-coordinating organoboron complexes is still scarcely
described, mainly represented by nitro group reduction and N-
S
S
E
O
N
F
O
N
F
1
8
B
acylation/alkylation, as well as, some examples of Pd-
R
R
4
a,19
F
F
catalytic coupling reactions.
Moreover, the most
problematic point of the postfunctionalization of such
compounds is their poor stability in hard reaction conditions.
2
0
Figure
1.
(a)
Synthesis
of
thiazolo[3,2-
c][1,3,5,2]oxadiazaborinine dyes, (b) modification of
thiazolo[3,2-c][1,3,5,2]oxadiazaborinines via LDA-mediated
electrophilation reaction.
The development of effective various C-C and C-heteroatom
bond formation reactions can open the way to large library of
new practically important N,O-coordinating organoboron
fluorophores. Consequently, research of such stable
synthetically modified complexes is actual scientific challenge.
One of the least studied classes of the N,O-coordinating
5
organoboron dyes is based on the oxadiazaborinine ring.
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Herein we report the simple method for postfunctionalization silylating,
Page 2 of 14
and
halogenating,
sulfenylating,
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
of thiazolo[3,2-c][1,3,5,2]oxadiazaborinines 1 based on direct
lithiation and following reaction with electrophiles (Figure 1b).
This transition-metal-free synthetic method enables the
incorporation of substituents ranging from electron-donating (E
ethoxycarboxylating reagents, we synthesized products 3a–f
and 4a–d with 4,5-disubstituted thiazole unit in very good
yields (67–88%).
=
Me, SiMe
3
) to highly electron-withdrawing (E = CN, SO
2
Ph,
Table 1. Scope for the LDA-Mediated Electrophilic
Postfunctionalization of Complex 1a.
CHO) in thiazolo[3,2-c][1,3,5,2]oxadiazaborinine core,
yielding a large library of novel fluorescent dyes. The influence
of the substituents E on photophysical properties of the obtained
complexes both in solution and the solid state was established.
Me N
2
1. LDA (1.05 eq),
N
-
78 °C, 30 min
S
1a
E
RESULTS AND DISCUSSION
2. electrophile
1.05 eq),
-78 °C, 60 min
O
N
F
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
(
B
Synthesis and Characterization. The regioselectivity of
organolithium-mediated electrophilic functionalization of 4,5-
unsubstituted 1,3-thiazoles depends on the acidity of thiazole
protons (H-5 > H-4) and occurs preferentially at position 5 of
the thiazole ring. The substitution at position 4 could be
realized for halogenation reaction in the presence of excess of
F
2a-l
entry Electrophile
E
Cl
Br
Br
I
Product
2a
2b
2b
2c
2d
2e
2b
2f
2g
2h
2i
2a
2j
Yield, %
67
2
7
1
2
3
4
5
6
7
8
9
CCl
CBr
Br
4
4
64
60
60
71
76
71
70
76
85
73
65
80
73
64
2
8
2
organolithium reagent caused by halogen-dance reaction.
I
2
Therefore, first of all, our attention was concerned on the
organolithium-mediated halogenation reaction of compound 1a
with 4,5-unsubstitued 1,3-thiazole unit. As an effective base, we
selected lithium diisopropylamide (LDA), which is well-known
mediator of the thiazole ring modification.
tetrachloride, carbon tetrabromide, bromine, and iodine were
tested as the halogenating electrophilic agents. In all cases, 5-
substituted thiazole derivatives (2a–c) were isolated. The
highest yields of the products (60–67%, Table 1, entries 1–4)
were achieved when the molar ratio of thiazole
substrate/LDA/electrophile was 1.00:1.05:1.05.
a
MeI
ClCO
Me
2
Me
CO
2
Me
Br-CN
Bt-CN
DMF
Br
CN
CHO
SiMe
SPh
Cl
a,b
28c,29
Carbon
1
0
1
2
3
4
5
Me
(PhS)
PhSO Cl
Bt-SO Ph
(PhSe)
Bu SnCl
3
SiCl
2
3
1
1
1
1
1
2
a,b
2
SO
SePh
SnBu
2
Ph
2
2k
2l
3
3
Next, these reaction conditions were expanded for several C-
electrophiles. In the case of methylation (Table 1, entry 5), the
a
b
with HMPA addition, Bt – benzotriazole.
cation-complexing
agent
(hexamethylphosphoramide,
30
Scheme 1. Synthesis of Benzotriazole-Based Electrophiles.
HMPA) was necessary for the reaction course; product 2d was
synthesized with 71% yield. The use of methyl chloroformate
and dimethylformamide (DMF) (Table 1, entries 6 and 9) gave
ester 2e and aldehyde 2g in 76% yield in both cases.
Interestingly, using cyanogen bromide as electrophile, the
obtained product had halogenide substituent (2b, entry 7 in
Table 1). Meanwhile, to synthesize compound 2f with cyano
group, benzotriazole-carbonitrile (Bt-CN) was selected as
N
PhSO2Cl,
N
N
N
NaH, THF,
0 °C, 30 min,
Py, toluene,
0 °C to RT, 12h
N
N
N
N
N
O
S
O
then BrCN,
°C to RT, 1.5h
N
H
94%
0
90%
Bt-H
Bt-CN
Bt-SO Ph
2
3
1
effective electrophilic cyanation reagent,
synthesized in the reaction of benzothriazole (Bt-H) with
cyanogen bromide under basic conditions with good yield
which was
Table 2. Scope for the LDA-Mediated Electrophilic
Postfunctionalization of Complexes 1b,c.
(90%, Scheme 1). Bt-CN was successfully used in the presence
Me N
2
of HMPA giving expected product 2f with 70% yield (entry 8
in Table 1).
1
. LDA (1.05 eq),
-78 °C, 30 min
N
B
1
b: R = Me
S
Furthermore, starting from compound 1a and using Si-, S-,
Se-, Sn-electrophiles, we obtained regioselectively
organoboron complexes 2h–l in good yields ranging from 64%
to 85% (Table 1, entries 10, 11, 13–15). Notably, analogically
to cyanation, sulphonation reaction did not occurred with
electrophilic halogenide (phenylsulfonyl chloride, entry 12 in
Table 1); chloro-substituted product 2a in 65% yield was
isolated in this case. Compound 2j with sulfone group was
successfully obtained in 80% yield using phenylsulfonyl-
1c: R = Ph
E
2
. electrophile
1.05 eq),
-78 °C, 60 min
O
N
F
(
R
F
3
a-f; 4a-d
entry
R
Electrophile
E
Me
SiMe
Cl
Br
SPh
2
CO Et
SiMe
Br
SPh
Product Yield, %
a
1
2
3
4
5
6
7
8
9
Me
Me
Me
Me
Me
Me
Ph
Ph
Ph
Ph
MeI
3a
3b
3c
3d
3e
3f
80
88
86
85
82
67
88
81
68
72
Me
CCl
CBr
(PhS)
ClCO Et
Me SiCl
CBr
(PhS)
ClCO Et
3
SiCl
3
4
32
4
benzotriazole (Bt-SO
2
Ph) as electrophile. The synthesis of
2
Bt-SO Ph was efficiently realized by sulfolation of
2
2
unsubstituted benzotriazole with phenylsulfonyl chloride in
basic conditions (Scheme 1).
Having in the hand the elaborated conditions for the effective
LDA-mediated electrophilation of complex 1a, we examined
this reaction for complexes 1b,c (Table 2). Using methylating,
3
3
4a
4b
4c
4d
4
2
1
0
2
2
CO Et
a
with HMPA addition.
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Structures of the synthesized products were confirmed by The solutions of the synthesized thiazolo[3,2-
1
13
19
77
119
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
NMR ( H, C, F, and, if possible, Se or Sn) spectroscopy,
high-resolution mass-spectrometry (HRMS), as well as, for
compounds 2c,d,j, 3a, and 3f, by single crystal X-ray analysis.
Thus, all H NMR spectra of compounds 2a–l displayed the
presence of a characteristic singlet signal for H-4 atom in the
c][1,3,5,2]oxadiazaborinines generally exhibited a strong
absorption band and intense emission in blue-green region.
Absorption spectra of the complexes had high-energy
shoulders, which were more clearly observed for the solutions
of the compounds 2d, 2h, 2l, 3a, 3b, 4a with donor substituents
1
range from 7.14 ppm for complex 2a to 8.06 ppm for aldehyde
3 3
(Me, SiMe , SnBu ) at the thiazole ring in nonpolar media (i.e.
2
g. Nota bene: compound 2d (Me-group at position 5 of
toluene) and were induced by vibrational transition. The
wavelengths of absorption (λabs) and emission (λem) maxima
were found to be dependent on the donor/acceptor strength of
the substituents E. The maxima were bathochromically shifted
with increasing acceptor strength. Thus, the incorporation of
halogen substituents in the thiazole unit (compounds 2a–c,
3c,d, 4b) slightly increased the wavelengths of absorption and
emission maxima, comparative to the corresponding parameters
of complexes 1a–c: λabs = 416–421 nm and λem = 447–451 nm
thiazole ring) is a regioisomer of analogue 1b (Me-group at
position 4 of thiazole ring), which exhibits the characteristic
singlet for H-5 atom at 6.05 ppm.
X-ray Analysis. The X-ray crystallographic structures of
complexes 2c,d,j, and 3a,f (Figures S1–S5 and Table S1–S6 in
the Supporting Information) unambiguously confirm not only
the position of the substituents E, but also invariability of
tetrahedral coordination of boron atom, as well as, the
coplanarity of donor (dimethylaminophenyl) and acceptor
25
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
for products 2a–c, 3c,d, 4b, while λabs = 405–409 nm and λem
439–444 nm for substrates 1a–c.
=
(thiazolo[3,2-c][1,3,5,2]oxadiazaborinine) units in the solid
state. The sulfur atom from phenylsulfone group has near-to-
tetrahedral coordination by two carbon and two oxygen atoms:
the C–S–C bond angle is 104.6°, the O–S–C bond angles are in
the range 105.9–108.6°, while the O-S-O bond angle is much
higher (121.3°) (Table S6 in the Supporting Information), and
slightly differs from the typical value (118.8°).
Photophysical Properties of the Solutions. Having
obtained large library of thiazolo[3,2-
c][1,3,5,2]oxadiazaborinines 2a–l, 3a–f, and 4a–d, we
investigated their photophysical properties. The absorption and
emission spectroscopic data of the dilute solution of these
compounds in toluene are summarized in Table 3. The
corresponding normalized spectra of the selected dyes are
shown in Figure 2. Additionally, the normalized absorption and
emission spectra and the spectroscopic data of the solutions of
oxadiazaborinines 2a–l, 3a–f, and 4a–d in five organic solvents
Much stronger changes were observed in the case of
compounds with different C-substituents (-Me, -CO Me, -CN,
2
-CHO). In particular, the incorporation of methyl group
(compounds 2d and 3a) provided almost no changes in the
absorption and emission properties comparatively to those of
the thiazolo[3,2-c][1,3,5,2]oxadiazaborinines 1a,b (Table 3),
except the increasing intensity of high-energy absorption
shoulder (Figure 2). Whereas, electron-withdrawing ester,
nitryl and aldehyde groups exhibited more considerable
influence on the photophysical parameters of the corresponding
33
compounds: λabs = 405 nm, 425 nm, 430 nm, 437 nm, and λem
=
439 nm, 464 nm, 470 nm, 481 nm for dyes 1a, 2e, 2f, and 2g,
respectively. The result of this dependency is also a growth of
-1
the Stokes shifts (Δν) from 1747 cm for compound 2d to 2093
-1
cm for aldehyde 2g. It should be noted that the influence of the
substituents at position 5 of the thiazole ring on the location of
absorption and emission maxima of the thiazolo[3,2-
c][1,3,5,2]oxadiazaborinines is definitely much higher than the
with
different
polarity
(toluene,
dichloromethane,
tetrahydrofurane, acetone, and acetonitrile) are given in the
Supporting Information (Figures S6–S27 and Table S7).
2
5
corresponding influence of the substituents at position 4.
Figure 2. Normalized absorption (solid lines) and emission (dashed lines) spectra of the solutions of the selected complexes in toluene.
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Table 3. Photophysical Properties of the Dilute Solutions of Complexes 1a–c, 2a–l, 3a–f, 4a–d in toluene.
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
-
1
-1
Δν (cm-1)
1912
1687
1927
1767
1767
1750
1747
1978
1979
2093
1843
1927
2079
1954
1799
2537
1791
1595
1595
1928
1751
1774
1552
2108
1807
-1
-1 a
Comp.
λ
abs (nm)
405
407
409
416
416
418
406
425
430
437
407
420
429
417
406
395
407
419
419
420
424
409
418
421
423
ε (M *cm )
56600
59300
56600
62000
58300
57500
57900
36300
32700
43100
59700
62500
68700
76100
56100
58000
48000
51200
59300
68500
63700
51700
62500
64200
87500
λ
em (nm)
439
437
444
449
449
451
437
464
470
481
440
457
471
454
438
439
439
449
449
457
458
441
447
462
458
Ф
τ, ns
2.22
2.24
2.06
2.01
1.80
0.63
1.54
1.84
1.68
2.64
1.82
1.90
2.47
1.51
1.71
1.71
1.74
2.00
1.81
1.85
2.15
1.68
1.37
1.66
1.64
B (M *cm )
56600
58707
53204
51500
44900
12100
48000
28700
21600
34100
50700
52500
57000
53300
47100
45800
39400
38900
46800
54800
52300
43500
39400
44900
74400
1
a
>0.99
0.99
0.94
0.83
0.77
0.21
0.83
0.79
0.66
0.79
0.85
0.84
0.83
0.70
0.84
0.79
0.82
0.76
0.79
0.80
0.82
0.84
0.63
0.70
0.85
1
b
1
c
2
a
2
b
2
c
2
d
2
e
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
2
f
2
g
2
h
2
i
2
j
2
k
2
l
3a
3b
3c
3d
3e
3f
4a
4b
4c
4
d
a
B = ε × Ф
The absorption maxima demonstrated almost no changes
with the variation of solvent polarity. Meanwhile, the emission
4 6
100 mV/s, 0.1 M Bu NPF as supporting electrolyte, and
ferrocene as the internal standard. Obtained from cyclic
voltammograms, the values of onset oxidation potentials
spectra
clearly
demonstrated
the
positive
onset
onset
solvatofluorochromism of all investigated organoboron
complexes (Figures S6–S27, Table S7 in the Supporting
Information), which is presumably due to an intramolecular
charge transfer (ICT) process in the excited state.
(Eox ) and onset reduction potentials (Ered ) were converted
into the corresponding values of ionization potentials (IPs) and
electron affinities (EAs), using equations IP = Eox
onset
+ 4.4 and
onset
EA = Ered
+ 4.4 (Table 4). IPs of the investigated
Solutions of the complexes in nonpolar solvents exhibited
high fluorescence quantum yields (Ф = 0.63–0.85 in toluene,
Table 3). The exception was observed for iodo derivative 2c:
this compound due to "heavy atom effect" demonstrated
significant decreasing of fluorescence efficiency (Ф = 0.21 in
toluene). The value of fluorescence quantum yield of all
investigated difluoroboron fluorophores decreased with the
increasing of the solvent polarity (Table S7, the Supporting
Information). The excited-state lifetimes (τ) of the solutions in
toluene vary from 0.63 to 2.64 ns, which was comparative with
the corresponding values for substrates 1a–c (τ = 2.06–2.24 ns,
Table 3).
All investigated thiazolo[3,2-c][1,3,5,2]oxadiazaborinines
are characterized by high value of the molecular fluorescence
brightness (B, the product of the molar absorption coefficient
and the fluorescence quantum yield) in the range from 12100 to
4400 M *cm for toluene solutions (Table 3), which indicated
evident perspectives of their practical applications.
oxadiazaborinines were assessed in the range of 5.01–5.21 eV.
Compounds with strong electron accepting substituents
exhibited slightly higher IPs: 5.13 (for 2g), 5.14 (2e, 2j) and
5.21 (2f) eV. EAs ranged from 2.22 eV for complex 3b to 2.73
eV for aldehyde 2g (Table 4).
Quantum Chemical Calculations. In order to gain more
insight into the electronic structures and the photophysical
properties
of
the
obtained
thiazolo[3,2-
c][1,3,5,2]oxadiazaborinines, density functional theory (DFT),
as well as time-dependent density functional theory (TD-DFT),
calculations have been performed by Gaussian-09 software
3
4
with the inclusion of DCM solvent effect through the integral-
equation-formalism polarizable continuum model (IEFPCM).
The ground-state geometries of most of the complexes have
been optimized at B3LYP functional and 6-31g(d) basis set.
However, to perform the calculations for iodo- and tin-
derivatives 2c and 2l, the mixed LANL2DZ/6-31g(d) basic set
was necessary to use, where LANL2DZ basic set was used for
I and Sn atoms, while 6-31g(d) basic set was used for the all
other atoms.
-1
-1
7
Electrochemical Properties. To investigate the redox
behaviour of the synthesized difluoroboron complexes, cyclic
voltammograms (Figures S28–S49 in the Supporting
Information) of the corresponding solutions in deoxygenated
dichloromethane were recorded, using a voltage scan rate of
The optimized geometries of the complexes (Figure 3 and
Figure S50 in the Supporting Information) are in good
agreement with the X-ray crystal structures (Figures S1–S5 in
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transition is mainly contributed by the HOMO→LUMO
the Supporting Information): 3-(4-dimethylaminophenyl)-
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
thiazolo[3,2-c][1,3,5,2]oxadiazaborinine core is planar, except
the tetrahedral coordinating boron unit. Phenylsulfone group in
complex 2j is twisted with respect to the rest of the molecule
and has near-to-tetrahedral geometry. Analogical geometry is
observed for molecules 2i, 2k, 3e and 4c with phenylthiolyl and
phenylselanyl substituents.
excitation.
Taken together, the computational results are in good
agreement with the experimentally obtained data and confirm
the influence of the substituents E on the absorption properties
of the corresponding compounds.
Solid-State Fluorescence Properties. The solid films of
compounds 2a–l, 3a–f, 4a–d demonstrated single broad
emission peaks (Figure 4). The exception was emission
spectrum of complex 2i, in which additional hypsochromic
shoulder was observed. The solid-state emission maxima of the
investigated dyes (Table S9 in the Supporting Information)
were bathochromically shifted, relative to those of the
corresponding dilute solutions
Table 4. Onset Oxidation and Onset Reduction Potentials,
Ionization Potentials and Electron Affinities of Compounds
2
a–l, 3a–f, 4a–d.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Compound Eoxonset, V Eredonset, V IP, eV EA, eV
E
g
, eVa
2
a
0.70
0.69
0.67
0.67
0.74
0.81
0.73
0.66
0.68
0.74
0.66
0.63
0.61
0.63
0.68
0.66
0.68
0.70
0.61
0.68
0.67
0.63
-1.92
-1.82
-2.03
-2.17
-1.84
-1.76
-1.67
-2.10
-1.99
-1.78
-2.02
-2.01
-2.17
-2.18
-1.96
-1.88
-2.00
-1.93
-2.10
-1.85
-2.00
-1.91
5.10
5.09
5.07
5.07
5.14
5.21
5.13
5.06
5.08
5.14
5.06
5.03
5.01
5.03
5.08
5.06
5.08
5.10
5.01
5.08
5.07
5.03
2.48
2.58
2.37
2.23
2.56
2.64
2.73
2.30
2.41
2.62
2.38
2.39
2.23
2.22
2.44
2.52
2.40
2.47
2.30
2.55
2.40
2.49
2.62
2.51
2.70
2.84
2.58
2.57
2.40
2.76
2.67
2.52
2.68
2.64
2.78
2.81
2.64
2.54
2.68
2.63
2.71
2.53
2.67
2.54
2
b
In the solid state, due to aggregation-caused quenching
2
c
(
2
ACQ), most of the complexes exhibited weak emissions (Ф ≤
0%). However, compound 2l exhibited an increased solid-state
fluorescence quantum yield of 44%. Due to the presence of
bulky lipophilic SnBu substituent, this difluoroboron
2
d
2
2
2
e
f
g
3
fluorophore possesses an extended intermolecular distance,
which could reduce the intermolecular π−π stacking in the solid
state and eventually restrain the ACQ effect.
2
h
2i
2j
2k
2
CONCLUSIONS
l
a
3
Conjugated with the donor 4-dimethylaminophenyl group
thiazolo[3,2-c][1,3,5,2]oxadiazaborinine can be easily
modified by direct regioselective lithiation of the thiazole unit.
This simple transition-metal-free synthetic method provides a
large library of novel fluorescent thiazole-based organoboron
complexes with varied substituents at position 5 of the thiazole
ring, including electron-donating or electron-withdrawing
groups. Photophysical and electrochemical properties of these
difluoroboron fluorophores can be effectively tuned by
manipulation of donor/acceptor strength of the incorporated
substituents. The incorporation of bulky lipophilic substituent
3
b
3
c
3
d
3
3
4
4b
4c
4d
e
f
a
a
E
g
= IP – EA
(SnBu
3
)
in the thiazolo[3,2-c][1,3,5,2]oxadiazaborinine
Similarly to unsubstituted complex 1a, the calculated highest
scaffold causes an increase of solid-state photoluminescence
quantum yield up to 44%.
occupied molecular orbitals (HOMOs) of compounds 2a–l are
mainly localized on the (N,N-dimethylamino)phenyl donor
group; while the lowest unoccupied molecular orbitals
(LUMOs) are delocalized along whole planar π-conjugated dye
scaffold (Figure 3). In the cases of compounds 2e–g,j, the
LUMOs are much shifted to the strong electron-withdrawing
EXPERIMENTAL SECTION
General. All reagent-grade chemicals [including n-butyllithium,
diisopropylamine, HMPA, electrophilic reagents] and solvents
were received from commercial suppliers (TCI, Aldrich, or Acros
Organics). Column chromatography was performed on silica gel
2 2
groups (CO Me, CN, CHO, and SO Ph), which causes the
increase of ICT character of emission of these dyes.
The frontier molecular orbital densities of compounds 3a–f
and 4a–d (Figure 3 and Figure S50 in the Supporting
Information) are analogical to its of dyes 2a–l; the methyl and
phenyl substituents at position 4 of the thiazole ring do not make
significant influence on the HOMO and LUMO distributions.
The HOMO and LUMO energy levels correlate with the
corresponding values of the ionization potentials and the
electron affinities, determined from cyclic voltammograms
(
Merck, 230-400 mesh). Melting points of all synthesized
compounds were measured on Automatic Melting Point System
OptiMelt, Stanford Research Systems). The NMR spectra were
recorded with Bruker Avance II 400 MHz (at 400 MHz, 100 MHz,
(
1
13
19
and 375 MHz for H, C, and F NMR spectra, respectively), or
Varian VNMRS 500 MHz (at 500 MHz, 125 MHz, 470 MHz, 95
MHz, and 186 MHz for
respectively) spectrometers for solutions in CDCl and TMS as the
internal standard.
Mass spectra were measured with Synapt G2-S HDMS (Waters
Inc) mass spectrometer equipped with an electrospray ion source
and q-TOF type mass analyser; or with magnetic sector mass
spectrometer AutoSpec Premier (Waters, USA), equipped with an
electron impact (EI) ion source and the EBE double focusing
geometry mass analyzer. Both instruments were controlled, and
recorded data were processed using MassLynx 4.1 software
package (Waters, USA).
1
H, 13C, 19F, 77Se, and 119Sn NMR spectra,
3
(Table 4). The incorporation of EWG into position 5 of the
thiazole ring causes the increase of the absolute value of the
HOMO and LUMO energy, as well as, the decrease of ΔEHOMO-
LUMO
.
TD-DFT results (Figures 51–75, Table S8 in the Supporting
Information) indicate that the lowest-energy absorption bands
of all investigated complexes calculated in the range 392–442
nm correspond to the S
0 1
→S transition, which is characterized
by high values of oscillator strength (f = 0.94–1.30). This
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1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Figure 3. Optimized geometries and frontier molecular orbitals of compounds 1a, 2a–l, 3a, and 4b.
UV-vis absorption spectra were recorded using Perkin Elmer
Lambda 35 spectrometer for ca. 10 M solutions of dyes. Emission
radiation at 100 K. Data reduction was done with CrysAlisPro
(Agilent Technologies, Version 1.171.35.21b). The obtained
-5
spectra were recorded using Edinburgh Instruments' FLS980
structures were determined by direct methods and refined using
SHELXL Software Package. Crystallographic data of compounds
-5
35
Fluorescence Spectrometer (λex = 374 nm) for both ca. 10
M
solutions and thin solid films of the investigated dyes. Thin film
samples were fabricated on the pre-cleaned quartz plates by using
spin-coating technique utilizing SPS-Europe Spin150 Spin
processor using 2.5 mg/ml solutions of the complexes in DCM.
Fluorescence quantum yields of the samples were obtained with a
2c, 2d, 2j, 3a, and 3f have been deposited with the Cambridge
Crystallographic Data Centre (CCDC) and can be obtained, free of
charge, from CCDC via https://www.ccdc.cam.ac.uk/structures/.
Synthesis. 1H-Benzo[d][1,2,3]triazole-1-carbonitrile (Bt-CN).
This compound was obtained in 90% yield (1.09 g) using a
literature procedure from benzotriazole (1.00 g, 8.39 mmol),
sodium hydride (60% in mineral oil, 0.37 g, 9.23 mmol) and
cyanogen bromide (0.98 g, 9.23 mmol).
3
1
calibrated integrating sphere in
a
FLS980 spectrometer.
Fluorescence decays of the solutions and of the solid state samples
were recorded with the PicoQuant PDL 820 picosecond pulsed
diode laser as an excitation source (λex = 374 nm) using a time-
correlated single photon counting technique. Electrochemical
experiments were performed using mAUTOLAB Type III
apparatus, glassy carbon, platinum coil and silver wire as working,
auxiliary and reference electrode, respectively.
Single crystals of organoboron complexes 2c, 2d, 2j, 3a, and 3f
were grown by the slow evaporation of their solution in
hexanes/DCM (1:1). The X-ray measurements were made on
SuperNova Agilent diffractometer using CuKα (λ = 1.54184 Å)
1-(Phenylsulfonyl)-1H-benzo[d][1,2,3]triazole
2
(Bt-SO Ph).
This compound was obtained using a modified literature
3
2
procedure. A solution of benzotriazole (1.00 g, 8.39 mmol) and
pyridine (1.5 equiv, 1.01 ml, 12.59 mmol) in dry toluene (12 mL)
was cooled to 0 °C. Then a solution of phenylsulfonyl chloride (1.2
equiv, 1.29 mL, 10.07 mmol) in toluene (3 mL) was added
dropwise. The reaction mixture was stirred overnight at room
tempera-
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1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Figure 4. Normalized solid-state emission spectra of complexes 2a–l, 3a–f, 4a–d (λex = 374 nm).
ture. Then water (10 mL) and ethyl acetate (15 mL) were added.
The organic layer was separated, washed with water (15 mL) and
additions of 2.5 M solution (66–75 µL) of n-butyllithium (1.1
equiv. 0.17–0.19 mmol) in hexanes and diisopropylamine (1.05
equiv, 0.16–0.18 mmol, 22–25 µL) to cooled THF (1 mL) at 0 °C
and stirring for 15 min] was added. The mixture was stirred for 30
min at –78 °C. Then, a solution of electrophilic reagent (1.05 equiv,
0.16–0.18 mmol) in THF (1 mL) was slowly added, and the stirring
was continued for 60 min at –78 °C. Next, a saturated aqueous
solution (10 mL) of NH Cl was added to quench the rest of LDA at
4
–78 °C. The reaction mixture was then brought to room temperature
and extracted with DCM (3 × 20 mL). The combined organic layers
brine (10 mL), and dried over anhydrous Na
were removed in vacuo. The obtained solid was recrystallized from
toluene to afford Bt-SO Ph in 94% (2.06 g) yield. Mp. 122.9–
124.1 °C, colorless needles. H NMR (400 MHz, CDCl
.15 (4H, m, Ar-H), 7.61–7.69 (2H, m, Ar-H), 7.44–7.56 (3H, m,
2 4
SO . The solvents
2
1
3
): δ = 8.04–
8
1
3
Ar-H) ppm; C {H} NMR (100 MHz, CDCl
35.2, 131.6, 130.3, 129.7 (2C), 127.9 (2C), 125.9, 120.6, 112.0
ppm.
3
): δ = 145.4, 137.1,
1
General procedure A: for organolithium-mediated postfunctio-
nalization of thiazolo[3,2-c][1,3,5,2]oxadiazaborinines without
additive. This reaction was conducted under an argon atmosphere.
A solution of LDA (1.05 equiv, 0.15–0.18 mmol) in THF (1 mL)
were dried over Na
was purified by column chromatography on silica gel.
2 4
SO , filtered, and concentrated. The product
4
4
4-(6-Chloro-1,1-difluoro-1H-1λ ,8λ -thiazolo[3,2-
c][1,3,5,2]oxadiazaborinin-3-yl)-N,N-dimethylaniline (2a) was
obtained in 67% yield (33 mg) using general procedure A from
compound 1a (44 mg, 0.15 mmol) and tetrachloromethane (15 µL,
0.16 mmol); and in 65% yield (32 mg) using general procedure B
from compound 1a (44 mg, 0.15 mmol) and benzenesulfonyl
chloride (20 µL, 0.16 mmol). The column chromatography
purification in both cases was performed with hexanes and DCM
mixtures (3:1 to 1:1, v/v) as eluent.
[previously obtained by sequential additions of 2.5 M solution (61–
7
5 µL) of n-butyllithium (1.1 equiv. 0.15–0.19 mmol) in hexanes
and diisopropylamine (1.05 equiv, 0.15–0.18 mmol, 20–25 µL) to
cooled THF (1 mL) at 0 °C and stirring for 15 min] was added to a
solution of thiazolo[3,2-c][1,3,5,2]oxadiazaborinine (1a–c, 1.0
equiv, 0.14–0.17 mmol) in dry THF (4 mL) at –78 °C. The mixture
was stirred for 30 min at –78 °C. Then, a solution of electrophilic
reagent (1.05 equiv, 0.15–0.18 mmol) in THF (1 mL) was slowly
added, and the stirring was continued for 60 min at –78 °C. Next, a
saturated aqueous solution (10 mL) of NH Cl was added to quench
4
the rest of LDA at –78 °C. The reaction mixture was then brought
to room temperature and extracted with DCM (3 × 20 mL). The
combined organic layers were dried over Na SO , filtered, and
2 4
concentrated. The product was purified by column chromatography
on silica gel.
General procedure B: for organolithium-mediated postfunctio-
nalization of thiazolo[3,2-c][1,3,5,2]oxadiazaborinines in the
presence of HMPA. This reaction was conducted under an argon
atmosphere. HMPA (5 equiv. 0.75–0.85 mmol, 130–148 µL) was
added to a solution of thiazolo[3,2-c][1,3,5,2]oxadiazaborinine
(1a–b, 1.0 equiv, 0.15–0.17 mmol) and in dry THF (4 mL) and the
mixture was cooled to –78 °C. Then a solution of LDA (1.05 equiv,
Me
N
Me
N
S
Cl
O
N
B
F
F
1
Mp. 228.5–230.5 °C, yellow powder. H NMR (500 MHz, CDCl
δ = 8.16 (2H, d, J = 9.2 Hz, Ar-H), 7.30 (1H, s, thiazole-H), 6.69
(2H, d, J = 9.2 Hz, Ar-H), 3.11 (6H, s, NMe
3
):
13
2
) ppm; C {H} NMR
(
125 MHz, CDCl ): δ = 172.4, 167.5, 154.4, 132.6 (2C), 127.0,
3
19
1
19.8, 117.2, 111.1 (2C), 40.2 (2C) ppm; F NMR (470 MHz,
CDCl
H] Calcd for C12
4
3
): δ = –136.54 (2F, m, BF
OF SCl 330.0451; Found 330.0439.
-(6-Bromo-1,1-difluoro-1H-1λ ,8λ -thiazolo[3,2-
2
) ppm. HRMS (ESI) m/z: [M +
+
H
12BN
3
2
4
4
c][1,3,5,2]oxadiazaborinin-3-yl)-N,N-dimethylaniline (2b) was
obtained in 60% (32 mg), 64% (34 mg), and 71% (38 mg) yields
0
.16–0.18 mmol) in THF (1 mL) [previously obtained by sequential
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from compound 1a (42 mg, 0.14 mmol) and bromine (26 mg, 0.16
Me
N
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
mmol), tetrabromomethane (50 mg, 0.15 mmol), or cyanogen
bromide (16 mg, 0.15 mmol), respectively, using general procedure
A. The column chromatography purification was performed with
hexanes and DCM mixtures (2:1 to 1.5:1, v/v) as eluent.
Me
Me
N
B
O
S
O
N
F
OMe
F
N
1
Me
Mp. 236.4–238.1 °C, yellow powder. H NMR (400 MHz, CDCl
δ = 8.20 (2H, d, J = 9.1 Hz, Ar-H), 8.04 (1H, s, thiazole-H), 6.68
(2H, d, J = 9.1 Hz, Ar-H), 3.94 (3H, s, OMe), 3.12 (6H, s, NMe
ppm; C {H} NMR (100 MHz, CDCl
154.8, 135.4, 133.1 (2C), 120.7, 116.8, 111.0 (2C), 53.0, 40.1 (2C)
ppm; F NMR (375 MHz, CDCl
HRMS (ESI) m/z: [M + Na] Calcd for C14
376.0715; Found 376.0707.
3
):
N
B
S
Br
2
)
O
N
F
13
3
): δ = 175.4, 168.3, 160.4,
F
1
19
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
Mp. 231.2–233.0 °C, yellow powder. H NMR (500 MHz, CDCl
3
):
3
): δ = –136.77 (2F, m, BF
2
) ppm.
H14BN O F SNa
+
δ = 8.16 (2H, d, J = 9.1 Hz, Ar-H), 7.40 (1H, s, thiazole-H), 6.69
3 3 2
1
3
(
(
1
2H, d, J = 9.1 Hz, Ar-H), 3.11 (6H, s, NMe
125 MHz, CDCl ): δ = 174.3, 167.3, 154.3, 132.6 (2C), 130.1,
17.2, 111.2 (2C), 101.7, 40.2 (2C) ppm; F NMR (470 MHz,
CDCl ): δ = –136.42 (2F, m, BF ) ppm. HRMS (ESI) m/z: [M +
SBrNa 395.9765; Found 395.9761.
2
) ppm; C {H} NMR
4
4
3
3-[4-(Dimethylamino)phenyl]-1,1-difluoro-1H-1λ ,8λ -
1
9
thiazolo[3,2-c][1,3,5,2]oxadiazaborinine-6-carbonitrile (2f) was
obtained in 70% yield (38 mg) using general procedure B from
compound 1a (50 mg, 0.17 mmol) and Bt-CN (26 mg, 0.18 mmol).
The column chromatography purification was performed with
hexanes and DCM mixtures (2:1 to 1:2, v/v) as eluent.
Me
3
2
+
3 2
Na] Calcd for C12H11BN OF
4
4
4-(1,1-Difluoro-6-iodo-1H-1λ ,8λ -thiazolo[3,2-
c][1,3,5,2]oxadiazaborinin-3-yl)-N,N-dimethylaniline (2c) was
obtained in 60% yield (41 mg) using general procedure A from
compound 1a (48 mg, 0.16 mmol) and iodine (43 mg, 0.17 mmol).
The column chromatography purification was performed with
hexanes and DCM mixtures (3:1 to 2:1, v/v) as eluent.
Me
N
Me
N
S
N
O
N
B
N
Me
F
F
1
N
B
Mp. 245.1–247.3 °C, yellow powder. H NMR (500 MHz, CDCl
δ = 8.20 (2H, d, J = 9.3 Hz, Ar-H), 7.89 (1H, s, thiazole-H), 6.69
(2H, d, J = 9.3 Hz, Ar-H), 3.94 (3H, s, OMe), 3.14 (6H, s, NMe
ppm; C {H} NMR (125 MHz, CDCl
139.3, 133.6 (2C), 116.0, 111.2 (2C), 110.5, 110.0, 40.1 (2C) ppm;
F NMR (470 MHz, CDCl ): δ = –136.15 (2F, m, BF ) ppm.
3 2
HRMS (ESI) m/z: [M + Na] Calcd for C13
343.0612; Found 343.0602.
3-[4-(Dimethylamino)phenyl]-1,1-difluoro-1H-1λ ,8λ -
thiazolo[3,2-c][1,3,5,2]oxadiazaborinine-6-carbaldehyde
was obtained in 76% yield (40 mg) using general procedure A from
compound 1a (48 mg, 0.16 mmol) and DMF (13 µL, 0.17 mmol).
This compound was also synthesized in a larger scale in 73% yield
(308 mg), starting from substrate 1a (385 mg, 1.30 mmol), DMF
(106 µL, 1.37 mmol), LDA (1.37 mmol) in THF (8 mL) [previously
obtained from cooled THF (8 mL) at 0 °C, 2.5 M solution (575 µL)
of n-butyllithium (1.43 mmol) in hexanes, and diisopropylamine
(1.37 mmol, 193 µL)] and THF (30 mL) using the same reaction
conditions. The column chromatography purification in both cases
was performed with hexanes and DCM mixtures (2:1 to 1:2, v/v)
as eluent.
3
):
S
I
O
N
F
2
)
1
3
F
3
): δ = 175.7, 169.0, 155.2,
1
Mp. 197.8–200.5 °C, yellow powder. H NMR (400 MHz, CDCl
3
):
1
9
δ = 8.16 (2H, d, J = 9.2 Hz, Ar-H), 7.50 (1H, s, thiazole-H), 6.67
13
+
(
2H, d, J = 9.2 Hz, Ar-H), 3.09 (6H, s, NMe
2
) ppm; C {H} NMR
H
11BN
4
OF
2
SNa
(
100 MHz, CDCl ): δ = 177.2, 167.2, 154.4, 136.1, 132.6 (2C),
3
1
9
4
4
117.1, 111.1 (2C), 61.3, 40.1 (2C) ppm; F NMR (375 MHz,
CDCl ): δ = –136.31 (2F, m, BF ) ppm. HRMS (ESI) m/z: [M +
H] Calcd for C12 OF SI 421.9807; Found 421.9793.
-(1,1-Difluoro-6-methyl-1H-1λ ,8λ -thiazolo[3,2-
3
2
(2g)
+
H
12BN
3
2
4
4
4
c][1,3,5,2]oxadiazaborinin-3-yl)-N,N-dimethylaniline (2d) was
obtained in 71% yield (38 mg) using general procedure B from
compound 1a (51 mg, 0.17 mmol) and methyl iodide (11 µL, 0.18
mmol). The column chromatography purification was performed
with hexanes and DCM mixtures (2:1 to 1:3, v/v) as eluent.
Me
N
Me
N
S
Me
O
N
Me
B
N
F
F
1
Me
Mp. 258.9–260.5 °C, yellow powder. H NMR (500 MHz, CDCl
3
):
N
B
O
S
δ = 8.17 (2H, d, J = 9.1 Hz, Ar-H), 7.14 (1H, d, J = 1.4 Hz, thiazole-
H), 6.71 (2H, d, J = 9.1 Hz, Ar-H), 3.09 (6H, s, NMe ), 2.42 (3H,
) ppm; C {H} NMR (125 MHz, CDCl ): δ =
72.7, 166.4, 153.8, 132.2 (2C), 125.9, 118.0, 112.4, 111.2 (2C),
O
N
2
1
3
d, J = 1.4 Hz, CH
3
3
F
F
1
1
4
Mp. 238.0–240.2 °C, orange powder. H NMR (500 MHz, CDCl
δ = 9.91 (1H, s, CHO), 8.23 (2H, d, J = 9.1 Hz, Ar-H), 8.06 (1H, s,
thiazole-H), 6.72 (2H, d, J = 9.1 Hz, Ar-H), 3.14 (6H, s, NMe
ppm; C {H} NMR (125 MHz, CDCl
154.9, 138.7, 133.5 (2C), 130.4, 116.8, 111.4 (2C), 40.3 (2C) ppm;
3
):
1
9
0.3 (2C), 12.6 ppm; F NMR (470 MHz, CDCl
) ppm. HRMS (ESI) m/z: [M + H] Calcd for
OF S 310.0997; Found 310.0988.
Methyl 3-[4-(dimethylamino)phenyl]-1,1-difluoro-1H-1λ ,8λ -
3
): δ = –136.94
+
(2F, m, BF
2
2
)
13
C
13
H
15BN
3
2
3
): δ = 180.6, 175.9, 168.8,
4
4
1
9
thiazolo[3,2-c][1,3,5,2]oxadiazaborinine-6-carboxylate (2e) was
obtained in 76% yield (40 mg) using general procedure A from
compound 1a (44 mg, 0.15 mmol) and methyl chloroformate (12
µL, 0.16 mmol). The column chromatography purification was
performed with hexanes and DCM mixtures (2:1 to 1:2, v/v) as
eluent.
F NMR (470 MHz, CDCl
3
): δ = –136.69 (2F, m, BF
2
) ppm.
+
HRMS (EI) m/z: [M] Calcd for C13
Found 323.0717.
H12BN O F S 323.0711;
3 2 2
4
4
4-{1,1-Difluoro-6-(trimethylsilyl)-1H-1λ ,8λ -thiazolo[3,2-
c][1,3,5,2]oxadiazaborinin-3-yl}-N,N-dimethylaniline (2h) was
obtained in 85% yield (50 mg) using general procedure A from
compound 1a (47 mg, 0.16 mmol) and trimethylsilyl chloride (21
µL, 0.17 mmol). The column chromatography purification was
ACS Paragon Plus Environment

Page 9 of 14
The Journal of Organic Chemistry
performed with hexanes and DCM mixtures (3:1 to 2:1, v/v) as
eluent.
performed with hexanes and DCM mixtures (3:1 to 2:1, v/v) as
eluent.
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
Me
Me
N
N
Me
Me
N
B
Me
Si Me
Me
N
B
S
S
Se
O
N
F
O
N
F
F
F
1
1
Mp. 186.4–188.0 °C, yellow powder. H NMR (500 MHz, CDCl
δ = 8.19 (2H, d, J = 9.1 Hz, Ar-H), 7.42 (1H, s, thiazole-H), 6.68
(2H, d, J = 9.1 Hz, Ar-H), 3.08 (6H, s, NMe ), 0.36 (9H, s, SiMe
): δ = 176.6, 166.4, 154.1,
34.1, 132.3 (2C), 126.6, 117.5, 110.9 (2C), 40.0 (2C), –0.8 (3C)
3
):
3
Mp. 209.4–211.5 °C, yellow powder. H NMR (500 MHz, CDCl ):
δ = 8.17 (2H, d, J = 9.2 Hz, Ar-H), 7.58 (1H, s, thiazole-H), 7.48–
2
3
)
7.52 (2H, m, Ar-H), 7.30–7.34 (3H, m, Ar-H), 6.70 (2H, d, J = 9.2
1
3
13
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
ppm; C {H} NMR (125 MHz, CDCl
3
Hz, Ar-H), 3.10 (6H, s, NMe
CDCl
129.8 (2C), 129.7, 128.4, 117.6, 113.6, 111.3 (2C), 40.2 (2C) ppm;
2
) ppm; C {H} NMR (125 MHz,
1
3
): δ = 176.6, 167.0, 154.2, 135.2, 132.6 (2C), 132.0 (2C),
1
9
ppm; F NMR (470 MHz, CDCl
3
): δ = –136.59 (2F, m, BF
2
) ppm.
2
+
19
77
HRMS (ESI) m/z: [M + H] Calcd for C15
68.1236; Found 368.1234.
-{1,1-Difluoro-6-(phenylthio)-1H-1λ ,8λ -thiazolo[3,2-
H
21BN
3
OF SSi
F NMR (470 MHz, CDCl
NMR (95 MHz, CDCl ): δ = 314.68 ppm. HRMS (ESI) m/z: [M +
OF SSe 452.0319; Found 452.0303.
3 2
): δ = –136.49 (2F, m, BF ) ppm; Se
3
3
4
4
+
4
H] Calcd for C18
H
17BN
3
2
4
4
c][1,3,5,2]oxadiazaborinin-3-yl}-N,N-dimethylaniline (2i) was
obtained in 73% yield (42 mg) using general procedure A from
compound 1a (42 mg, 0.14 mmol) and diphenyl disulfide (33 mg,
4-{1,1-Difluoro-6-(tributylstannyl)-1H-1λ ,8λ -thiazolo[3,2-
c][1,3,5,2]oxadiazaborinin-3-yl}-N,N-dimethylaniline (2l) was
obtained in 64% yield (56 mg) using general procedure A from
compound 1a (44 mg, 0.15 mmol) and tributyltin chloride (42 µL,
0.16 mmol). The column chromatography purification was
performed with hexanes and DCM mixtures (3:1 to 2:1, v/v) as
eluent.
0
.15 mmol). The column chromatography purification was
performed with hexanes and DCM mixtures (3:1 to 2:1, v/v) as
eluent.
Me
N
Me
Me
Me
N
N
S
Me
Me
S
N
B
S
O
N
B
Sn
O
N
F
F
F
1
Mp. 218.2–219.5 °C, yellow powder. H NMR (500 MHz, CDCl
δ = 8.17 (2H, d, J = 9.2 Hz, Ar-H), 7.56 (1H, s, thiazole-H), 7.32–
.39 (4H, m, Ar-H), 7.29 (1H, m, Ar-H), 6.67 (2H, d, J = 9.2 Hz,
3
):
F
Me
7
1
Mp. 94.0–96.1 °C, yellow powder. H NMR (500 MHz, CDCl
3
): δ
13
Ar-H), 3.10 (6H, s, NMe
2 3
) ppm; C {H} NMR (125 MHz, CDCl ):
=
8.19 (2H, d, J = 9.1 Hz, Ar-H), 7.33 (1H, s, thiazole-H), 6.69 (2H,
δ = 175.6, 167.3, 154.4, 134.4, 134.4, 132.6 (2C), 129.6 (2C), 129.3
d, J = 9.1 Hz, Ar-H), 3.08 (6H, s, NMe
2
), 1.56 (6H, m, 3 × CH
), 0.91 (9H, t, J = 7.3
) ppm; C {H} NMR (125 MHz, CDCl ): δ = 177.3,
2
),
1
9
(2C), 127.9, 122.5, 117.1, 111.0 (2C), 40.1 (2C) ppm; F NMR
(470 MHz, CDCl ): δ = –136.61 (2F, m, BF ) ppm. HRMS (ESI)
404.0874; Found
1
2 2
.34 (6H, m, 3 × CH ), 1.17 (6H, m, 3 × CH
13
3
2
Hz, 3 × CH
3
3
+
m/z: [M + H] Calcd for C18
04.0866.
-{1,1-Difluoro-6-(phenylsulfonyl)-1H-1λ ,8λ -thiazolo[3,2-
3 2 2
H17BN OF S
165.7, 154.0, 134.7, 132.1 (2C), 123.2, 117.8, 110.9 (2C), 40.0
4
19
(
(
(
2C), 28.8 (3C), 27.2 (3C), 13.6 (3C), 11.1 (3C) ppm; F NMR
4
4
4
119
470 MHz, CDCl
3
): δ = –136.61 (2F, m, BF
): δ = –29.54 ppm. HRMS (ESI) m/z: [M + H]
OF SSn 586.1897; Found 586.1876.
-{1,1-Difluoro-6,7-dimethyl-1H-1λ ,8λ -thiazolo[3,2-
2
) ppm; Sn NMR
c][1,3,5,2]oxadiazaborinin-3-yl}-N,N-dimethylaniline (2j) was
obtained in 80% yield (52 mg) using general procedure B from
+
186 MHz, CDCl
3
Calcd for C24
H
39BN
3
2
compound 1a (44 mg, 0.15 mmol) and Bt-SO
2
Ph (40 mg, 0.16
4
4
4
mmol). The column chromatography purification was performed
with hexanes and DCM mixtures (1:1 to 1:3, v/v) as eluent.
c][1,3,5,2]oxadiazaborinin-3-yl}-N,N-dimethylaniline (3a) was
obtained in 80% yield (42 mg) using general procedure B from
compound 1b (50 mg, 0.16 mmol) and methyl iodide (11 µL, 0.18
mmol). The column chromatography purification was performed
with hexanes and DCM mixtures (1:1 to 1:2, v/v) as eluent.
Me
Me
N
Me
N
S
S
O
O
N
N
B
O
Me
F
F
N
B
S
1
Mp. 225.5–227.3 °C, yellow powder. H NMR (500 MHz, CDCl
δ = 8.15 (2H, d, J = 9.2 Hz, Ar-H), 7.99 (2H, d, J = 7.2 Hz, Ar-H),
.91 (1H, s, thiazole-H), 7.69 (1H, t, J = 7.4 Hz, Ar-H), 7.60 (2H,
dd, J = 7.4 Hz, J = 7.2 Hz, Ar-H), 6.67 (2H, d, J = 9.2 Hz, Ar-H),
3
):
Me
O
N
7
Me
F
F
1
Mp. 227.6–229.0 °C, yellow powder. H NMR (500 MHz, CDCl
3
):
1
3
3
.12 (6H, s, NMe
2 3
) ppm; C {H} NMR (125 MHz, CDCl ): δ =
δ = 8.17 (2H, d, J = 9.1 Hz, Ar-H), 6.69 (2H, d, J = 9.1 Hz, Ar-H),
1
76.3, 168.6, 154.9, 140.1, 134.7, 134.5, 133.4 (2C), 130.6, 129.9
13
3
{
1
.08 (6H, s, NMe
H} NMR (125 MHz, CDCl
32.0 (2C), 119.3, 118.0, 111.1 (2C), 40.2 (2C), 12.0, 11.2 ppm;
2
), 2.38 (3H, s, CH
3 3
), 2.31 (3H, s, CH ) ppm; C
19
(
2C), 127.6 (2C), 116.5, 111.2 (2C), 40.2 (2C) ppm; F NMR (470
MHz, CDCl ): δ = –136.22 (2F, m, BF ) ppm. HRMS (ESI) m/z:
Na 458.0592; Found
3
): δ = 170.7, 165.6, 153.8, 136.4,
3
2
+
[M + Na] Calcd for C18
458.0589.
H
16BN
3
O
3
F
2
S
2
19
3 2
F NMR (470 MHz, CDCl ): δ = –133.88 (2F, m, BF ) ppm.
+
HRMS (ESI) m/z: [M + H] Calcd for C14
Found 324.1150.
H
17BN
3
OF
2
S 324.1153;
4
4
4
-{1,1-Difluoro-6-(phenylselanyl)-1H-1λ ,8λ -thiazolo[3,2-
c][1,3,5,2]oxadiazaborinin-3-yl}-N,N-dimethylaniline (2k) was
obtained in 73% yield (50 mg) using general procedure A from
compound 1a (45 mg, 0.15 mmol) and diphenyl diselenide (50 mg,
4
4
4
-{1,1-Difluoro-7-methyl-6-(trimethylsilyl)-1H-1λ ,8λ -
thiazolo[3,2-c][1,3,5,2]oxadiazaborinin-3-yl}-N,N-
dimethylaniline (3b) was obtained in 88% yield (48 mg) using
general procedure A from compound 1b (44 mg, 0.14 mmol) and
trimethylsilyl chloride (19 µL, 0.15 mmol). The column
0
.16 mmol). The column chromatography purification was
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 10 of 14
chromatography purification was performed with hexanes and
DCM mixtures (2:1 to 1:1, v/v) as eluent.
Me
N
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
Me
Me
N
B
S
N
Me
S
O
N
F
N
S
Me
Si Me
Me
Me
F
O
N
1
B
Mp. 231.6–233.5 °C, yellow powder.
H NMR (500 MHz, CDCl3):
δ = 8.19 (2H, d, J = 9.1 Hz, Ar-H), 7.30–7.34 (2H, m, Ar-H), 7.22–
7.26 (3H, m, Ar-H), 6.69 (2H, d, J = 9.1 Hz, Ar-H), 3.10 (6H, s,
Me
F
F
1
Mp. 149.8–151.0 °C, yellow powder. H NMR (500 MHz, CDCl
δ = 8.19 (2H, d, J = 9.1 Hz, Ar-H), 6.68 (2H, d, J = 9.1 Hz, Ar-H),
3.08 (6H, s, NMe ), 2.53 (3H, s, CH -thiazole), 0.38 (9H, s, SiMe
ppm; C {H} NMR (125 MHz, CDCl ): δ = 175.2, 165.5, 153.9,
46.6, 132.1 (2C), 119.0, 117.7, 111.0 (2C), 40.1 (2C), 15.5, –0.3
3
):
13
NMe
CDCl
(2C), 127.9 (2C), 127.2, 117.4, 114.7, 111.1 (2C), 40.2 (2C), 13.1
2
), 2.59 (3H, s, CH
3
-thiazole) ppm; C {H} NMR (125 MHz,
2
3
3
)
3
): δ = 173.9, 166.5, 154.2, 147.6, 135.2, 132.5 (2C), 129.5
1
3
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
3
1
9
1
(t, JC–F = 2.6 Hz) ppm; F NMR (470 MHz, CDCl
(2F, m, BF ) ppm. HRMS (ESI) m/z: [M + Na] Calcd for
OF Na 440.0850; Found 440.0849.
Ethyl 3-[4-(dimethylamino)phenyl]-1,1-difluoro-7-methyl-1H-
1λ ,8λ -thiazolo[3,2-c][1,3,5,2]oxadiazaborinine-6-carboxylate
(3f) was obtained in 67% yield (44 mg) using general procedure A
from compound 1b (53 mg, 0.17 mmol) and ethyl chloroformate
(21 µL, 0.18 mmol). The column chromatography purification was
performed with hexanes and DCM mixtures (1:1 to 1:2, v/v) as
eluent.
3
): δ = –133.98
1
9
+
(
3C) ppm; F NMR (470 MHz, CDCl
3
): δ = –133.70 (2F, m, BF
ppm. HRMS (ESI) m/z: [M + H] Calcd for C16 OF SSi
82.1392; Found 382.1380.
-(6-Chloro-1,1-difluoro-7-methyl-1H-1λ ,8λ -thiazolo[3,2-
2
)
2
+
H
23BN
3
2
C
19
H
18BN
3
2 2
S
3
4
4
4
4
4
c][1,3,5,2]oxadiazaborinin-3-yl)-N,N-dimethylaniline (3c) was
obtained in 86% yield (48 mg) using general procedure A from
compound 1b (50 mg, 0.16 mmol) and tetrachloromethane (16 µL,
0
.17 mmol). The column chromatography purification was
performed with hexanes and DCM mixtures (3:1 to 2:1, v/v) as
eluent.
Me
Me
N
Me
N
Me
N
B
O
S
N
B
S
O
N
F
OEt
Cl
O
N
F
Me
F
Me
1
F
Mp. 231.0–233.6 °C, yellow powder. H NMR (500 MHz, CDCl
δ = 8.20 (2H, d, J = 9.2 Hz, Ar-H), 6.68 (2H, d, J = 9.2 Hz, Ar-H),
4.37 (2H, q, J = 7.2 Hz, OCH ), 3.11 (6H, s, NMe ), 2.82 (3H, s,
thiazole-CH ), 1.39 (3H, t, J = 7.2 Hz, CH CH ) ppm; C {H}
NMR (125 MHz, CDCl ): δ = 173.2, 167.5, 160.9, 154.5, 149.9,
132.8 (2C), 116.9, 114.2, 111.0 (2C), 61.9, 40.1 (2C), 14.3, 14.0
ppm; F NMR (470 MHz, CDCl ): δ = –133.55 (2F, m, BF ) ppm.
3 2
HRMS (ESI) m/z: [M + H] Calcd for C16
Found 382.1204.
3
):
1
Mp. 237.1–239.7 °C, yellow powder. H NMR (500 MHz, CDCl
3
):
δ = 8.16 (2H, d, J = 8.9 Hz, Ar-H), 6.68 (2H, d, J = 8.9 Hz, Ar-H),
2
2
1
3
13
3
.10 (6H, s, NMe
2
), 2.44 (3H, s, CH
3
-thiazole) ppm; C {H} NMR
3
2
3
(
125 MHz, CDCl
3
): δ = 170.7, 166.7, 154.3, 138.1, 132.4 (2C),
3
19
1
17.2, 113.7, 111.0 (2C), 40.1 (2C), 12.0 ppm; F NMR (470
): δ = –133.81 (2F, m, BF ) ppm. HRMS (ESI) m/z:
[M + H] Calcd for C13 OF SCl 344.0607; Found 344.0606.
-(6-Bromo-1,1-difluoro-7-methyl-1H-1λ ,8λ -thiazolo[3,2-
1
9
MHz, CDCl
3
2
+
+
H
14BN
3
2
H
19BN
3
O
3
F
2
S 382.1208;
4
4
4
4
4
c][1,3,5,2]oxadiazaborinin-3-yl)-N,N-dimethylaniline (3d) was
obtained in 85% yield (50 mg) using general procedure A from
compound 1b (47 mg, 0.15 mmol) and tetrabromomethane (50 mg,
4-{1,1-Difluoro-7-phenyl-6-(trimethylsilyl)-1H-1λ ,8λ -
thiazolo[3,2-c][1,3,5,2]oxadiazaborinin-3-yl}-N,N-
dimethylaniline (4a) was obtained in 88% yield (59 mg) using
general procedure A from compound 1c (56 mg, 0.15 mmol) and
trimethylsilyl chloride (20 µL, 0.16 mmol). The column
chromatography purification was performed with hexanes and
DCM mixtures (3:1 to 1.5:1, v/v) as eluent.
0
.15 mmol). The column chromatography purification was
performed with hexanes and DCM mixtures (2:1 to 1.5:1, v/v) as
eluent.
Me
N
Me
Me
N
N
S
Me
Br
N
B
Me
Si Me
Me
S
O
N
B
O
N
F
Me
F
F
1
Mp. 224.1–226.6 °C, yellow powder. H NMR (400 MHz, CDCl
3
):
F
δ = 8.16 (2H, d, J = 9.1 Hz, Ar-H), 6.68 (2H, d, J = 9.1 Hz, Ar-H),
1
3
3.09 (6H, s, NMe
2
), 2.54 (3H, s, CH
3
-thiazole) ppm; C {H} NMR
1
Mp. 195.1–197.8 °C, yellow powder. H NMR (500 MHz, CDCl
δ = 8.19 (2H, d, J = 9.1 Hz, Ar-H), 7.42–7.49 (5H, m, Ar-H), 6.69
(2H, d, J = 9.1 Hz, Ar-H), 3.08 (6H, s, NMe ), 0.08 (9H, s, SiMe
): δ = 175.1, 165.9, 153.9,
49.9, 132.2 (2C), 132.0, 130.6 (2C), 129.6, 127.8 (2C), 122.7,
3
):
(
100 MHz, CDCl ): δ = 172.8, 166.6, 154.3, 140.5, 132.4 (2C),
3
1
9
1
17.2, 111.1 (2C), 97.6, 40.1 (2C), 13.4 ppm; F NMR (375 MHz,
): δ = –133.82 (2F, m, BF ) ppm. HRMS (ESI) m/z: [M +
H] Calcd for C13 OF SBr 388.0102; Found 388.0086.
-{1,1-Difluoro-7-methyl-6-(phenylthio)-1H-1λ ,8λ -
thiazolo[3,2-c][1,3,5,2]oxadiazaborinin-3-yl}-N,N-
2
3
)
CDCl
3
2
13
ppm; C {H} NMR (125 MHz, CDCl
3
+
H
14BN
3
2
1
1
4
4
4
19
18.0, 111.1 (2C), 40.2 (2C), –0.2 (3C) ppm; F NMR (470 MHz,
): δ = –131.43 (2F, m, BF ) ppm. HRMS (ESI) m/z: [M +
SSiNa 466.1368; Found 466.1370.
CDCl
3
2
dimethylaniline (3e) was obtained in 82% yield (52 mg) using
general procedure A from compound 1b (47 mg, 0.15 mmol) and
diphenyl disulfide (35 mg, 0.16 mmol). The column
chromatography purification was performed with hexanes and
DCM mixtures (2:1 to 1.5:1, v/v) as eluent.
+
Na] Calcd for C21
3 2
H24BN OF
4
4
4
-(6-Bromo-1,1-difluoro-7-phenyl-1H-1λ ,8λ -thiazolo[3,2-
c][1,3,5,2]oxadiazaborinin-3-yl)-N,N-dimethylaniline (4b) was
obtained in 81% yield (55 mg) using general procedure A from
compound 1c (56 mg, 0.15 mmol) and tetrabromomethane (53 mg,
.16 mmol). The column chromatography purification was
performed with hexanes and DCM mixtures (3:1 to 2:1, v/v) as
eluent.
0
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The Journal of Organic Chemistry
ASSOCIATED CONTENT
Me
N
1
2
3
4
5
6
Me
Supporting Information
N
B
S
The Supporting Information is available free of charge via the
Internet at http://pubs.acs.org at DOI:
Br
O
N
F
ORTEP diagrams for the X-ray structures and crystal data of
complexes; additional photophysical data in solutions, cyclic
voltammograms; photophysical properties of complexes in the
solid state; fluorescence decays of dyes; NMR spectra of all
synthesized compounds (PDF)
F
1
Mp. 200.5–202.8 °C, yellow powder. H NMR (500 MHz, CDCl
δ = 8.17 (2H, d, J = 9.2 Hz, Ar-H), 7.53–7.58 (2H, m, Ar-H), 7.47–
.53 (3H, m, Ar-H), 6.68 (2H, d, J = 9.2 Hz, Ar-H), 3.10 (6H, s,
3
):
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
7
13
NMe
2 3
) ppm; C {H} NMR (125 MHz, CDCl ): δ = 173.1, 166.8,
Crystal data of 2c (CIF)
Crystal data of 2d (CIF)
Crystal data of 2j (CIF)
Crystal data of 3a (CIF)
Crystal data of 3f (CIF)
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
54.3, 143.5, 132.6 (2C), 130.3 (2C), 130.0, 128.8, 128.3 (2C),
1
9
117.1, 111.0 (2C), 99.4, 40.1 (2C) ppm; F NMR (470 MHz,
CDCl ): δ = –131.27 (2F, m, BF ) ppm. HRMS (ESI) m/z: [M +
SBrNa 472.0078; Found 472.0076.
3
2
+
Na] Calcd for C18
-{1,1-Difluoro-7-phenyl-6-(phenylthio)-1H-1λ ,8λ -
thiazolo[3,2-c][1,3,5,2]oxadiazaborinin-3-yl}-N,N-
3 2
H15BN OF
4
4
4
dimethylaniline (4c) was obtained in 68% yield (49 mg) using
general procedure A from compound 1c (56 mg, 0.15 mmol) and
diphenyl disulfide (35 mg, 0.16 mmol). The column
chromatography purification was performed with hexanes and
DCM mixtures (2:1 to 1:1, v/v) as eluent.
INFORMATION
Me
Corresponding Author
N
Me
Mykhaylo A. Potopnyk – Institute of Organic Chemistry,
Polish Academy of Sciences, Kasprzaka 44/52, 01-224,
Warsaw, Poland, orcid.org/0000-0002-4543-2785; Email:
potopnyk@gmail.com
mykhaylo.potopnyk@icho.edu.pl
N
S
S
O
N
F
B
and
F
1
Other Authors
Mp. 240.8–242.8 °C, yellow powder. H NMR (500 MHz, CDCl
δ = 8.18 (2H, d, J = 9.0 Hz, Ar-H), 7.53 (2H, d, J = 7.7 Hz, Ar-H),
.44–7.50 (3H, m, Ar-H), 7.31 (2H, dd, J = 7.6 Hz, J = 7.1 Hz, Ar-
H), 7.23–7.28 (3H, m, Ar-H), 6.66 (2H, d, J = 9.0 Hz, Ar-H), 3.10
3
):
Dmytro Volyniuk – Department of Polymer Chemistry and
Technology, Kaunas University of Technology, Barsausko
59, LT-51423 Kaunas, Lithuania, orcid.org/0000-0003-
7
1
3
(
1
6H, s, NMe
66.7, 154.3, 148.7, 135.2, 132.6 (2C), 130.3 (2C), 129.9, 129.4
2C), 129.1, 129.0 (2C), 128.0 (2C), 127.6, 118.3, 117.3, 111.1
2 3
) ppm; C {H} NMR (125 MHz, CDCl ): δ = 173.9,
3
526-2679
Roman Luboradzki – Institute of Physical Chemistry, Polish
Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw,
Poland, orcid.org/0000-0001-8910-230X
Magdalena Ceborska – Institute of Physical Chemistry,
Polish Academy of Sciences, Kasprzaka 44/52, 01-224,
Warsaw, Poland, orcid.org/0000-0001-5555-771X
Iryna Hladka – Department of Polymer Chemistry and
Technology, Kaunas University of Technology, Barsausko
59, LT-51423 Kaunas, Lithuania, orcid.org/0000-0002-
6864-4254
(
(
19
2C), 40.1 (2C) ppm; F NMR (470 MHz, CDCl
) ppm. HRMS (ESI) m/z: [M + Na] Calcd for
OF Na 502.1007; Found 502.0984.
Ethyl 3-[4-(dimethylamino)phenyl]-1,1-difluoro-7-phenyl-1H-
3
): δ = –131.25
+
(2F, m, BF
C
2
24
H
20BN
3
2 2
S
4
4
1
(
λ ,8λ -thiazolo[3,2-c][1,3,5,2]oxadiazaborinine-6-carboxylate
4d) was obtained in 72% yield (48 mg) using general procedure A
from compound 1c (56 mg, 0.15 mmol) and ethyl chloroformate
15 µL, 0.16 mmol). The column chromatography purification was
(
performed with hexanes and DCM mixtures (2:1 to 1:1, v/v) as
eluent.
Yan Danyliv – Department of Polymer Chemistry and
Technology, Kaunas University of Technology, Barsausko
59, LT-51423 Kaunas, Lithuania, orcid.org/0000-0001-
Me
N
Me
9
645-0337
N
B
O
S
Juozas V. Grazulevicius – Department of Polymer
Chemistry and Technology, Kaunas University of
Technology, Barsausko 59, LT-51423 Kaunas, Lithuania,
orcid.org/0000-0002-4408-9727
O
N
F
OEt
F
1
Mp. 208.6–210.3 °C, yellow powder. H NMR (400 MHz, CDCl
δ = 8.20 (2H, d, J = 9.2 Hz, Ar-H), 7.44–7.53 (5H, m, Ar-H), 6.69
(2H, d, J = 9.2 Hz, Ar-H), 4.16 (2H, q, J = 7.2 Hz, OCH ), 3.10
(6H, s, NMe
NMR (100 MHz, CDCl
3
):
Notes
The authors declare no competing financial interest.
2
3
1
2
), 1.11 (3H, t, J = 7.2 Hz, CH
): δ = 173.3, 167.7, 160.0, 154.5, 150.3,
32.9 (2C), 129.9, 129.8 (2C), 129.4, 127.7 (2C), 117.2, 116.7,
2 3
CH ) ppm; C {H}
DEDICATION
This paper is dedicated to Professor Mykola D. Obushak on his 65th
birthday.
3
1
1
1
9
11.2 (2C), 61.9, 40.2 (2C), 13.8 ppm; F NMR (375 MHz,
): δ = –130.99 (2F, m, BF ) ppm. HRMS (ESI) m/z: [M +
SNa 466.1184; Found 466.1175.
CDCl
3
2
+
ACKNOWLEDGMENT
We would like to acknowledge Poland’s National Science Centre
(UMO-2019/03/X/ST4/00037) for financial support. The
3 3 2
Na] Calcd for C21H20BN O F
Keywords:
oxadiazaborinine • lithiation • fluorescence
organoboron
complex
•
1,3-thiazole
•
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Page 12 of 14
calculation research was supported in part by PLGrid
Infrastructure.
(8) (a) Yu, C.; Jiao, L.; Zhang, P.; Feng, Z.; Cheng, C.; Wei, Y.;
Mu, X.; Hao, E. Highly Fluorescent BF Complexes of Hydrazine–
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
2
Schiff Base Linked Bispyrrole. Org. Lett. 2014, 16, 3048–3051. (b)
Zatsikha, Y. V.; Maligaspe, E.; Purchel, A. A.; Didukh, N. O.;
Wang, Y.; Kovtun, Y. P.; Blank, D. A.; Nemykin, V. N. Tuning
Electronic Structure, Redox, and Photophysical Properties in
Asymmetric NIR-Absorbing Organometallic BODIPYs. Inorg.
Chem. 2015, 54, 7915–7928. (c) Zatsikha, Y. V.; Didukh, N. O.;
Nemez, D.; Schlachter, A. C.; Karsenti, P.-L.; Kovtun, Y. P.;
Harvey, P. D.; Nemykin, V. N. Ferrocene–BODIPYmerocyanine
Dyads: New NIR Absorbing Platforms with Optical Properties
Susceptible to Protonation. Chem. Commun. 2017, 53, 7612–7615.
REFERENCES
(1) (a) Li, P.; Chan, H.; Lai, S.-L.; Ng, M.; Chan, M.-Y.; Yam, V.
W.-W. Four-Coordinate Boron Emitters with Tridentate Chelating
Ligand for Efficient and Stable Thermally Activated Delayed
Fluorescence Organic Light-Emitting Devices. Angew. Chem. Int. Ed.
2019, 58, 9088–9094. (b) Köhling, J.; Kozel, V.; Jovanov, V.; Pajkert,
R.; Tverdomed, S. N.; Gridenco, O.; Fugel, M.; Grabowsky, S.;
Röschenthaler, G.-V.; Wagner, V. Synthesis and Characterization of
Oxazaborinin Phosphonate for Blue OLED Emitter Applications.
ChemPhysChem 2019, 20, 665–671.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
(d) Didukh, N. O.; Yakubovskyi, V. P.; Zatsikha, Y. V.; Rohde, G.
(2) Yu, Z.; Wu, Y.; Xiao, L.; Chen, J.; Liao, Q.; Yao, J.; Fu, H.
T.; Nemykin, V. N.; Kovtun, Y. P. Flexible BODIPY Platform That
Offers an Unexpected Regioselective Heterocyclization Reaction
toward Preparation of 2‑Pyridone[a]‑Fused BODIPYs. J. Org.
Chem. 2019, 84, 2133−2147.
Organic Phosphorescence Nanowire Lasers. J. Am. Chem. Soc.
2017, 139, 6376−6381.
(3) (a) Zhang, P.; Liu, W.; Niu, G.; Xiao, H.; Wang, M.; Ge, J.;
Wu, J.; Zhang, H.; Li, Y.; Wang, P. Coumarin-Based Boron
Complexes with Aggregation-Induced Emission. J. Org. Chem.
(9) Zatsikha, Y V.; Didukh, N. O.; Swedin, R. K.; Yakubovskyi,
V. P.; Blesener, T. S.; Healy, A. T.; Herbert, D. E.; Blank, D. A.;
Nemykin, V. N.; Kovtun, Y. P. Preparation of Viscosity-Sensitive
Isoxazoline/Isoxazolyl-Based Molecular Rotors and Directly
Linked BODIPY−Fulleroisoxazoline from the Stable meso-(Nitrile
Oxide)-Substituted BODIPY. Org. Lett. 2019, 21, 5713–5718.
(10) (a) Ma, F.; Zhou, L.; Liu, Q.; Li, C.; Xie, Y. Selective
Photocatalysis Approach for Introducing ArS Units into BODIPYs
through Thiyl Radicals. Org. Lett. 2019, 21, 733–736. (b) Wang,
D.; Cheng, C.; Wu, Q.; Wang, J.; Kang, Z.; Guo, Z.; Wu, H.; Hao,
E.; Jiao, L. Visible-Light Excitation of BODIPYs Enables Self-
Promoted Radical Arylation at Their 3,5-Positions with Diazonium
Salts. Org. Lett. 2019, 21, 5121–5125.
(11) (a) Feng, Z.; Jiao, L.; Feng, Y.; Yu, C.; Chen, N.; Wei, Y.;
Mu, X.; Hao, E. Regioselective and Stepwise Syntheses of
Functionalized BODIPY Dyes through Palladium-Catalyzed
Cross-Coupling Reactions and Direct C−H Arylations. J. Org.
Chem. 2016, 81, 6281−6291. (b) Yang, X.; Jiang, L.; Yang, M.;
Zhang, H.; Lan, J.; Zhou, F.; Chen, X.; Wu, D.; You, J. Pd-
Catalyzed Direct C−H Functionalization/Annulation of BODIPYs
with Alkynes to Access Unsymmetrical Benzo[b]‑Fused
BODIPYs: Discovery of Lysosome-Targeted Turn-On Fluorescent
Probes. J. Org. Chem. 2018, 83, 9538–9546. (c) Belmonte-
Vázquez, J. L.; Avellanal-Zaballa, E.; Enríquez-Palacios, E.;
Cerdán, L.; Esnal, I.; Bañuelos, J.; Villegas-Gómez, C.; López
Arbeloa, I.; Peña-Cabrera, E. Synthetic Approach to Readily
Accessible Benzofuran-Fused Borondipyrromethenes as Red-
Emitting Laser Dyes. J. Org. Chem. 2019, 84, 2523–2541.
(12) (a) Miao, W.; Feng, Y.; Wu, Q.; Sheng, W.; Li, M.; Liu, Q.;
Hao, E.; Jiao, L. Phenanthro[b]‑Fused BODIPYs through Tandem
Suzuki and Oxidative Aromatic Couplings: Synthesis and
Photophysical Properties. J. Org. Chem. 2019, 84, 9693–9704. (b)
Taguchi, D.; Nakamura, T.; Horiuchi, H.; Saikawa, M.;
Nabeshima, T. Synthesis and Unique Optical Properties of
Selenophenyl BODIPYs and Their Linear Oligomers. J. Org.
Chem. 2018, 83, 5331–5337. (c) Tabero, A.; García-Garrido, F.;
Prieto-Castañeda, A.; Palao, E.; Agarrabeitia, A. R.; García-
Moreno, I.; Villanueva, A.; de la Moya. S.; Ortiz, M. J. BODIPYs
Revealing Lipid Droplets as Valuable Targets for Photodynamic
Theragnosis. Chem. Commun. 2020, 56, 940–943.
2
017, 82, 3456−3462. (b) Qiu, F.; Zhang, N.; Tang, R.; Zhou, M.;
Wang, Y.; Wei, W.; Bi, S.; Han, S.; Zhang, F. Asymmetric Boron-
Cored Aggregation-Induced Emission Luminogen with Multiple
Functions Synthesized through Stepwise Conversion from a
Symmetric Ligand. J. Org. Chem. 2018, 83, 12977−12984.
(4) (a) Dai, C.; Yang, D.; Zhang, W.; Fu, X.; Chen, Q.; Zhu, C.;
Cheng, Y.; Wang, L. Boron ketoiminate-based conjugated
polymers with tunable AIE behaviours and their applications for
cell imaging J. Mater. Chem. B 2015, 3, 7030–7036. (b) Zhao, N.;
Ma, C.; Yang, W.; Yin, W.; Wei, J.; Li, N. Facile Construction of
Boranil Complexes with Aggregation-Induced Emission
Characteristics and Their Specific Lipid Droplet Imaging
Applications. Chem. Commun. 2019, 55, 8494–8497. (c) Kong, L.;
Huang, Z.; Zhang, S.-S.; Song, J.; Zhang, Y.-Y.; Bai, X.-Y.; Yang,
J.-X.; Li, L. A Facile Strategy to Realize a Single/Double Photon
Excitation-Dependent Photosensitizer for Imaging-Guided
Phototherapy Against HeLa Cancer Cells at Separate Irradiation
Channels. Chem. Commun. 2020, 56, 571–574. (d) Ren, X.; Zhang,
F.; Luo, H.; Liao, L.; Song, X.; Chen, W. Red-Emitting Boron
Difluoride Complexes with a Mega-Large Stokes Shift and
Unexpectedly High Fluorescence Quantum Yield. Chem. Commun.
2
020, 56, 2159–2162.
5) Frath, D.; Massue, J.; Ulrich, G.; Ziessel, R. Luminescent
(
Materials: Locking p-Conjugated and Heterocyclic Ligands with
Boron(III). Angew. Chem. Int. Ed. 2014, 53, 2290–2310.
(6) (a) Yakubovskyi, V. P.; Didukh, N. O.; Zatsikha, Y. V.;
Kovtun, Y. P. A New Approach to the Synthesis of meso-CN-
Substituted BODIPYs. ChemistrySelect 2016, 1, 1462–1466. (b)
Didukh, N. O.; Zatsikha, Y. V.; Rohde, G. T.; Blesener, T. S.;
Yakubovskyi, V. P.; Kovtun, Y. P.; Nemykin, V. N. NIR
Absorbing Diferrocene-Containing meso-Cyano-BODIPY with a
UV-Vis-NIR Spectrum Remarkably Close to That of Magnesium
Tetracyanotetraferrocenyltetraazaporphyrin. Chem. Commun.
2
016, 52, 11563–11566. (c) Lv, X.; Li, T.; Wu, Q.; Yu, C.; Jiao, L.;
Hao, E. Polybrominated BOPHY Dyes: Synthesis, Reactivity, and
Properties. J. Org. Chem. 2018, 83, 1134–1145. (d) Yu, C.; Huang,
Z.; Wang, X.; Miao, W.; Wu, Q.; Wong, W.-Y.; Hao, E.; Xiao, Y.;
Jiao, L. A Family of Highly Fluorescent and Unsymmetric
Bis(BF
2
)
Chromophore Containing Both Pyrrole and
(13) Palao, E.; Duran-Sampedro, G.; de la Moya, S.; Madrid, M.;
N‑Heteroarene Derivatives: BOPPY. Org. Lett. 2018, 20, 4462–
García-López, C.; Agarrabeitia, A. R.; Verbelen, B.; Dehaen, W.;
Boens, N.; Ortiz, M. J. Exploring the Application of the Negishi
Reaction of HaloBODIPYs: Generality, Regioselectivity, and
Synthetic Utility in the Development of BODIPY Laser Dyes. J.
Org. Chem. 2016, 81, 3700−3710.
4
3
466. (e) Satoh, T.; Fujii, K.; Kimura, Y.; Matano, Y. Synthesis of
,5-Disubstituted BODIPYs Bearing N‑Containing Five-
Membered Heteroaryl Groups via Nucleophilic C−N Bond
Formation. J. Org. Chem. 2018, 83, 5274−5281.
(7) Patalag, L. J.; Ulrichs, J. A.; Jones, P. G., Werz, D. B.
(14) Leen, V.; Yuan, P.; Wang, L.; Boens, N.; Dehaen, W.
Decorated BODIPY Fluorophores and Thiol-Reactive
Fluorescence Probes by an Aldol Addition. Org. Lett. 2017, 19,
2090–2093.
Synthesis of Meso-Halogenated BODIPYs and Access to Meso-
Substituted Analogues. Org. Lett. 2012, 14, 6150–6153.
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Page 13 of 14
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(
15) (a) Verbelen, B.; Leen, V.; Wang, L.; Boens, N.; Dehaen, W.
Ketzer, A.; Meyer, A. R.; Rodrigues, L. V.; Nogara, P. A.; Rocha,
J. B. T.; Zanatta, N.; Martins, M. A. P. 1,1-Difluoro-3-
aryl(heteroaryl)-1H-pyrido[1,2-c][1,3,5,2]oxadiazaborinin-9-ium-
1-uides: Synthesis; Structure; and Photophysical, Electrochemical,
and BSA-Binding Studies. New J. Chem. 2018, 42, 1913–1920. (c)
Yamaji, M.; Kato, S.; Tomonari, K.; Mamiya, M.; Goto, K.;
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
Direct palladium-catalysed C–H arylation of BODIPY dyes at the
- and 3,5-positions. Chem. Commun. 2012, 48, 9129–9131. (b)
Chong, H.; Lin, H.-A.; Shen, M.-Y.; Liu, C.-Y.; Zhao, H.; Yu, H.
Step-Economical Syntheses of Functional BODIPY-EDOT
π‑Conjugated Materials through Direct C−H Arylation. Org. Lett.
3
2
015, 17, 3198–3201. (c) Chong, H.; Fron, E.; Liu, Z.; Boodts, S.;
Okamoto, H.; Nakamura, Y.; Tani, F. Blue Fluorescence from BF
2
Thomas, J.; Harvey, J. N.; Hofkens, J.; Dehaen, W.; Van der
Auweraer, M.; Smet, M. Acid-Sensitive BODIPY Dyes: Synthesis
through Pd-Catalyzed Direct C(sp )–H Arylation and
Complexes of N,O-Benzamide Ligands: Synthesis, Structure, and
Photophysical Properties. Inorg. Chem. 2017, 56, 12514–12519.
(22) (a) Hachiya, S.; Inagaki, T.; Hashizume, D.; Maki, S.; Niwa,
H.; Hirano, T. Synthesis and Fluorescence Properties of
Difluoro[amidopyrazinato-O,N]boron Derivatives: A New Boron-
Containing Fluorophore. Tetrahedron Lett. 2010, 51, 1613–1615.
(b) Hachiya, S.; Hashizume, D.; Ikeda, H.; Yamaji, M.; Maki, S.;
3
Photophysics. Chem. Eur. J. 2017, 23, 4687–4699. (d) Verbelen,
B.; Boodts, S.; Hofkens, J.; Boens, N.; Dehaen, W. Radical C–H
Arylation of the BODIPY Core with Aryldiazonium Salts:
Synthesis of Highly Fluorescent Red-Shifted Dyes. Angew. Chem.
Int. Ed. 2015, 54, 4612–4616.
(16) (a) Lv, F.; Yu, Y.; Hao, E.; Yu, C.; Wang, H.; Jiao, L.; Boens,
N. Copper-catalyzed a-benzylation of BODIPYs via radical-
triggered oxidative cross-coupling of two C–H bonds. Chem.
Commun. 2018, 54, 9059–9062. (b) Tang, B.; Lv, F.; Chen, K.;
Jiao, L.; Liu, Q.; Wang, H.; Hao, E. Development of BODIPY Dyes
with Versatile Functional Groups at 3,5-Positions from Diacyl
Peroxides via Cu(II)-Catalyzed Radical Alkylation. Chem.
Commun. 2019, 55, 4691–4694.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
2
Niwa, H.; Hirano, T. Spectroscopic properties of BF complexes of
N-(5-phenyl-2-pyrazinyl) pivalamides exhibiting fluorescence in
solution and solid state. J. Photochem. Photobiol. A: Chem. 2016,
331, 206–214.
(23) (a) Du, M.-L.; Hu, C.-Y.; Wang, L.-F.; Li, C.; Han, Y.-Y.;
Gan, X.; Chen, Y.; Mu, W.-H.; Huang, M. L.; Fu, W.-F. New
Members of Fluorescent 1,8-Naphthyridine-Based BF
Compounds: Selective Binding of BF with Terminal Bidentate
2
2
N^N^O and N^C^O Groups and Tunable Spectroscopy Properties.
Dalton Trans. 2014, 43, 13924–13931. (b) Wu, Y.-Y.; Chen, Y.;
Gou, G.-Z.; Mu, W.-H.; Lv, X.-J.; Du, M.-L.; Fu, W.-F. Large
Stokes Shift Induced by Intramolecular Charge Transfer in N,O-
(17) Sheng, W.; Zheng, Y.-Q.; Wu, Q.; Wu, Y.; Yu, C.; Jiao, L.;
Hao, E.; Wang, J.-Y.; Pei, J. Synthesis, Properties, and
Semiconducting Characteristics of BF
Bisphenanthrene-Fused Azadipyrromethenes. Org. Lett. 2017, 19,
893–2896.
18) (a) Frath, D.; Azizi, S.; Ulrich, G.; Ziessel, R. Chemistry on
2
Complexes of β,β-
Chelated Naphthyridine–BF
5226–5229. (c) Wu, Y.-Y.; Chen, Y.; Mu, W.-H.; Lv, X.-J.; Fu,
W.-F. Naphthyridine–BF Complexes with an Amide-Containing
2
Complexes. Org. Lett. 2012, 14,
2
(
2
Boranils: An Entry to Functionalized Fluorescent Dyes. Org. Lett.
2012, 14, 4774–4777. (b) Du, M.-L.; Hu, C.-Y.; Wang, L.-F.; Li,
C.; Han, Y.-Y.; Gan, X.; Chen, Y.; Mu, W.-H.; Huang, M. L.; Fu,
W.-F. New Members of Fluorescent 1,8-Naphthyridine-Based BF
Compounds: Selective Binding of BF with Terminal Bidentate
N^N^O and N^C^O Groups and Tunable Spectroscopy Properties.
Dalton Trans. 2014, 43, 13924–13931. (c) Wu, G. F.; Xu, Q. L.;
Guo, L. E.; Zang, T. N.; Tan, R.; Tao, S. T.; Ji, J. F.; Hao, R. T.;
Zhang, J. F.; Zhou, Y. 1,8-Naphthyridine-Based Boron Complexes:
Visible Colorimetric Probes for Highly Selective Sensing of
Phosphoric Ion. Tetrahedron Lett. 2015, 56, 5034–5038.
Di-2-picolylamine Receptor: Synthesis, Structures and Photo-
Induced Electron Transfer. J. Photochem. Photobiol. A: Chem.
2013, 272, 73–79. (d) Wu, G. F.; Xu, Q. L.; Guo, L. E.; Zang, T.
N.; Tan, R.; Tao, S. T.; Ji, J. F.; Hao, R. T.; Zhang, J. F.; Zhou, Y.
1,8-Naphthyridine-Based Boron Complexes: Visible Colorimetric
Probes for Highly Selective Sensing of Phosphoric Ion.
Tetrahedron Lett. 2015, 56, 5034–5038. (e) Bonacorso, H. G.;
Calheiro, T. P.; Iglesias, B. A.; Berni, I. R. C.; da Silva Júnior, E.
2
2
1
1
N.; Rocha, J. B. T.; Zanatta, N.; Martins, M. A. P. Synthesis, B-
1
9
and F NMR Spectroscopy, and Optical and Electrochemical
Properties of Novel 9-Aryl-3-(aryl/heteroaryl)-1,1-difluoro-7-
(trifluoromethyl)-1H-[1,3,5,2]oxadiazaborinino[3,4-
(19) (a) Suenaga, K.; Tanaka, K.; Chujo, Y. Heat-Resistant
Mechanoluminescent Chromism of the Hybrid Molecule Based on
Boron Ketoiminate Modified Octasubstituted Polyhedral
Oligomeric Silsesquioxane. Chem. Eur. J. 2017, 23, 1409–1414.
(b) Potopnyk, M. A.; Volyniuk, D.; Luboradzki, R.; Ceborska, M.;
Hladka, I.; Danyliv, Y.; Gražulevičius, J. V. Application of the
Suzuki−Miyaura Reaction for the Postfunctionalization of the
Benzo[4,5]thiazolo[3,2‑c][1,3,5,2]oxadiazaborinine Core: An
Approach toward Fluorescent Dyes. J. Org. Chem. 2019, 84, 5614–
a][1,8]naphthyridin-11-ium-1-uide Complexes. Tetrahedron Lett.
2016, 57, 5017–5021.
(24) Zhang, K.; Zheng, H.; Hua, C.; Xin, M.; Gao, J.; Li, Y.
Novel Fluorescent N,O-Chelated Fluorine-Boron Benzamide
Complexes Containing Thiadiazoles: Synthesis and Fluorescence
Characteristics. Tetrahedron 2018, 74, 4161–4167.
(25) (a) Potopnyk, M. A.; Lytvyn, R.; Danyliv, Y.; Ceborska, M.;
Bezvikonnyi, O.; Volyniuk, D.; Gražulevičius, J. V. N,O π-
2
Conjugated 4‑Substituted 1,3-Thiazole BF Complexes: Synthesis
and Photophysical Properties. J. Org. Chem. 2018, 83, 1095–1105.
(b) Potopnyk, M. A.; Lytvyn, R.; Danyliv, Y.; Ceborska, M.;
Bezvikonnyi, O.; Volyniuk, D.; Gražulevičius, J. V. Correction to
2
N,O π‑Conjugated 4‑Substituted 1,3-Thiazole BF Complexes:
Synthesis and Photophysical Properties. J. Org. Chem. 2018, 83,
5876.
5
626. (c) Huang, J.; Wang, Y.; Van Hecke, K.; Pereshivko, O. P.;
Peshkov, V. A. Studies on Functionalization of N,O-Chelated
Isoquinoline-Enol Boron Complexes. Eur. J. Org. Chem. 2019,
2490–2497.
(20) (a) Urban, M.; Durka, K.; Jankowski, P.; Serwatowski, J.;
Luliński, S. Highly Fluorescent Red-Light Emitting Bis(boranils)
Based on Naphthalene Backbone. J. Org. Chem. 2017, 82,
8
G.; Nawara, K.; Jankowski, P.; Luliński, S. The effect of locking
π-conjugation in organoboron moieties in the structures of
luminescent tetracoordinate boron complexes. Dalton Trans. 2019,
48, 8642–8663.
234−8241. (b) Urban, M.; Durka, K.; Górka, P.; Wiosna-Sałyga,
(26) Potopnyk, M. A.; Volyniuk, D.; Ceborska, M.; Cmoch, P.;
Hladka,
I.;
Danyliv,
Y.;
Gražulevičius,
J.
V.
Benzo[4,5]thiazolo[3,2‑c][1,3,5,2]oxadiazaborinines: Synthesis,
Structural, and Photophysical Properties. J. Org. Chem. 2018, 83,
12129–12142.
(27) Wu, Y.-J. Thiazoles and Benzothiazoles. Top. Heterocycl.
Chem. 2012, 29, 307–328.
(28) (a) Stanetty, P.; Schnürch, M.; Mereiter, K.; Mihovilovic M.
D. Investigations of the Halogen Dance Reaction on N-Substituted
2-Thiazolamines. J. Org. Chem. 2005, 70, 567–574. (b)
Holzweber, M.; Schnürch, M.; Stanetty, P. Polysubstituted
(21) (a) Grabarz, A. M.; Laurent, A. D.; Jędrzejewska, B.;
Zakrzewska, A.; Jacquemin, D.; Ośmiałowski, B. The Influence of
the π‐Conjugated Spacer on Photophysical Properties of
Difluoroboranyls Derived from Amides Carrying a Donor Group.
J. Org. Chem. 2016, 81, 2280–2292. (b) Bonacorso, H. G.;
Calheiro, T. P.; Iglesias, B. A.; Acunha, T. V.; Franceschini, S. Z.;
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 14 of 14
Thiazole Derivatives via the Halogen-Dance Reaction. Synlett
(33) CSD v5.4 update February 2019 for 3653 structures
containing 5549 C-SO -Ph fragments.
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
5
5
5
6
2007, 2007, 3016–3018. (c) Schnürch, M.; Khan, A. F.;
Mihovilovic, M. D.; Stanetty, P. Polyarylated Thiazoles via a
Combined Halogen Dance – Cross-Coupling Strategy. Eur. J. Org.
Chem. 2009, 3228–3236. (d) Havel, S.; Khirsariya, P.; Akavaram,
N.; Paruch, K.; Carbain, B. Preparation of 3,4-Substituted-5-
Aminopyrazoles and 4‑Substituted-2-Aminothiazoles. J. Org.
Chem. 2018, 83, 15380−15405.
2
(34) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G.
E.; Robb, M. A.; Cheeseman, J. R.; Scalmani, G.; Barone, V.;
Mennucci, B.; Petersson, G. A.; Nakatsuji, H.; Caricato, M.; Li, X.;
Hratchian, H. P.; Izmaylov, A. F.; Bloino, J.; Zheng, G.;
Sonnenberg, J. L.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.;
Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.;
Nakai, H.; Vreven, T.; Montgomery, J. A., Jr.; Peralta, J. E.;
Ogliaro, F.; Bearpark, M.; Heyd, J. J.; Brothers, E.; Kudin, K. N.;
Staroverov, V. N.; Keith, T.; Kobayashi, R.; Normand, J.;
Raghavachari, K.; Rendell, A.; Burant, J. C.; Iyengar, S. S.;
Tomasi, J.; Cossi, M.; Rega, N.; Millam, J. M.; Klene, M.; Knox,
J. E.; Cross, J. B.; Bakken, V.; Adamo, C.; Jaramillo, J.; Gomperts,
R.; Stratmann, R. E.; Yazyev, O.; Austin, A. J.; Cammi, R.;
Pomelli, C.; Ochterski, J. W.; Martin, R. L.; Morokuma, K.;
Zakrzewski, V. G.; Voth, G. A.; Salvador, P.; Dannenberg, J. J.;
Dapprich, S.; Daniels, A. D.; Farkas, O.; Foresman, J. B.; Ortiz, J.
V.; Cioslowski, J.; Fox, D. J. Gaussian 09, revision D.01; Gaussian,
Inc.: Wallingford, CT, USA, 2013.
(29) Deng, S.; Taunton, J. Organolithium-Mediated
Diversification of Peptide Thiazoles. Org. Lett. 2005, 7, 299–301.
(30) (a) Ma, Y.; Collum, D. B. Lithium Diisopropylamide-
Mediated Reactions of Imines, Unsaturated Esters, Epoxides, and
Aryl Carbamates: Influence of Hexamethylphosphoramide and
Ethereal Cosolvents on Reaction Mechanisms. J. Am. Chem. Soc.
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
2
007, 129, 14818–14825. (b) Reich, H. J. What’s Going on with
These Lithium Reagents? J. Org. Chem. 2012, 77, 5471−5491.
(31) (a)Katritzky, A. R.; Akue-Gedu, R.; Vakulenko, A. V. C-
Cyanation with 1-Cyanobenzotriazole, Arkivoc 2007, 3, 5–12. (b)
Katritzky, A. R.; Kirichenko, N.; Rogovoy, B. V. Synthesis of
mono- and N,N-disubstituted ureas. Arkivoc 2003, 8, 8–14.
(
32) Katritzky, A. R.; Abdel-Fattah, A. A. A.; Vakulenko, A. V.;
(35) Sheldrick, G. M. A Short History of SHELX. Acta Cryst.
2008, A64, 112–122.
Tao, H. N-Sulfonylbenzotriazoles as Advantageous Reagents for
C-Sulfonylation. J. Org. Chem. 2005, 70, 9191–9197.
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