Synthesis of 5-(Aryl)amino-1,2,3-triazole-containing 2,1,3-Benzothiadiazoles via Azide–Nitrile Cycloaddition Followed by Buchwald–Hartwig Reaction

Abstract

An efficient access to the novel 5-(aryl)amino-1,2,3-triazole-containing 2,1,3-benzothiadiazole derivatives has been developed. The method is based on 1,3-dipolar azide–nitrile cycloaddition followed by Buchwald–Hartwig cross-coupling to afford the corresponding N-aryl and N,N-diaryl substituted 5-amino-1,2,3-triazolyl 2,1,3-benzothiadiazoles under NHC-Pd catalysis. The one-pot diarylative Pd-catalyzed heterocyclization opens the straightforward route to triazole-linked carbazole-benzothiadiazole D-A systems. The optical and electrochemical properties of the compound obtained were investigated to estimate their potential application as emissive layers in OLED devises. The quantum yield of photoluminescence (PLQY) of the synthesized D-A derivatives depends to a large extent on electron-donating strengths of donor (D) component, reaching in some cases the values closed to 100%. Based on the most photoactive derivative and wide bandgap host material mCP, a light-emitting layer of OLED was made. The device showed a maximum brightness of 8000 cd/m² at an applied voltage of 18 V. The maximum current efficiency of the device reaches a value of 3.29 cd/A.

1. Introduction

Polyheteroaromatic compounds containing donor–acceptor (D-A) units linked through π-conjugation have been drawing considerable attention due to their unique electrochemical and photochemical properties. They have found many important applications in organic electronics and luminescence materials [1,2,3]. In the past decade, various electron-deficient (hetero)aromatics have been widely used as acceptor blocks in developing advanced functional materials. Among them, 2,1,3-benzothiadiazole (BTD) derivatives are recognized as privileged building blocks for assembling various optoelectronic devices [4], e.g., organic light-emitting diodes (OLEDs) [5,6], field effect transistors (OFETs) [7,8,9], solar cells (OSCs) [10,11,12,13,14], luminescent solar concentrators (LSCs) [15], as well as fluorescent tags for molecular and cellular imaging [16,17,18,19]. The successes of these benzothiadiazole-based D-A molecules are mainly beneficial from their ability to provide for intramolecular charge-transfer effects. The nature of donor and acceptor components and the linker between them are particularly crucial factors that affect the properties of such compounds [20]. The introduction of rigid chromophores with twisted molecular geometry or additional substituents into the linker can prevent unfavorable π-aggregates in the solid state, which often causes fluorescence quenching. Therefore, the development of new benzothiadiazole-based molecules with extended π-conjugation is currently of great interest.

The aromatic triazole ring is a versatile and readily installed linkage that has been used to extend the conjugation between different aromatic systems. Usually, it can be easily achieved via copper-catalyzed azide-alkyne cycloaddition, well known as “click” reaction. The beneficial effect of 1,2,3-triazole-linked BTD derivatives has been demonstrated for some dyes with a high photo and chemical stability in their excited states, which is a very desirable feature for both the technological and biological applications of new fluorophores [18,21,22,23,24,25].

An alternative route to 1,2,3-triazole core includes dipolar [3 + 2]-cycloaddition reaction (DCR) between azides and monosubstituted acetonitriles furnishing the corresponding 5-amino substituted products [26,27,28,29,30], which are impossible to obtain using classical azide–alkyne ligation. The presence of the amino group in these compounds provides a unique opportunity to tune their properties by introducing various functional substituents. Based on DCR methodology, we have recently developed an efficient pathway to polyarylated 5-amino-1,2,3-triazoles [31,32] (Scheme 1a). Now, we wish to report on the first application of this approach in combination with subsequent Buchwald–Hartwig reaction to the synthesis of novel 5-(aryl)amino-1,2,3-triazole-linked 2,1,3-benzothiadiazole derivatives (Scheme 1b).

2. Results

2.1. Synthesis

Starting nitrile 3a was synthesized by the Pd-catalyzed cross-coupling reaction of readily available mono-Br-substituted BTD 1 [33,34] with boropinacolate derivative of 2-phenylacetonitrile under standard Suzuki conditions. The reversed approach has proved to be more effective for the preparation of nitrile 3b. In this case, coupling between specially prepared 4-BPin-substituted BTD 2 (see Section 3.2) and ortho-Br 2-phenylacetonitrile led to the formation of the desired BTD-containing nitrile 3b in an acceptable yield using the same catalytic system (Scheme 2).

Then, following our previous experience [31] and literature precedents [29], we performed the pre-optimization of the dipolar [3 + 2]-cycloaddition (DCR) for the reaction of BTD-nitrile 3a with benzyl azide by screening simple catalysts (K₂CO₃, Cs₂CO₃, KOtBu) and solvents (DMF, DMSO) under moderate heating (40–80 °C). As a result, we found that the best yield of the desired product 4a (94%) can be achieved using 3.0 equiv. of azide, 50 mol.% of KOtBu in DMSO solution at 70 °C for 3 h. With a lower catalyst loading of catalyst (20–30 mol.%) or azide (1–2 equiv.), the reaction became less efficient with respect to rate and yield.

These conditions were further applied for the cycloaddition of nitriles 3a and 3b with different aliphatic and aromatic azides to afford the corresponding 5-amino-1,2,3-triazole-linked BTDs 4a–g in good to excellent yields (Scheme 3).

The Buchwald–Hartwig amination (BHA) is one of the most efficient cross-coupling reactions to access a wide range of N-mono- and N,N-disubstituted aryl amines. Despite noticeable advances in this area [35,36,37,38,39], coupling heteroaromatic amines with arylhalides is still a challenging transformation that often requires time-consuming searches for optimal conditions and catalytic systems [40,41,42,43,44,45,46,47]. In our previous study, we revealed that palladium complex with expanded-ring NHC ligand (THP-Dipp)Pd(cinn)Cl (er-NHC-Pd) is the most competent catalyst in the BHA reaction for low-reactive 5-amino-1,2,3-triazoles [32]. Now, we investigated its activity in the BHA of amino-triazoles 4 with different (het)aryl bromides. First, we checked the reaction of 4a with phenyl bromide using the same conditions, namely, equal amounts of the reagents were heated in 1,4-dioxane at 110 °C (oil bath temperature) in the presence of 2 mol.% of er-NHC-Pd catalyst and 3.0 equiv. of sodium tert-butoxide for 24 h. As a result, the desired cross-coupling product 5a was isolated in 58% yield. The increase in the catalyst loading up to 5 mol.% and the amount of phenyl bromide up to 5 equiv. allowed reaching the full conversion of the starting amine 4a and, as a consequence, improving the yield of 5a to 91% (Scheme 4). With these conditions in hand, a series of N-aryl substituted 5-amino-1,2,3-triazole-linked BTDs 5a–f was synthesized in good to excellent yields (Scheme 4). It should be noted that N,N-diarylated products were not detected in the reaction mixtures despite using a large excess of amine component. This phenomenon can be rationalized by the unique feature of Pd-catalyst with bulky NHC ligand [48,49].

It was previously shown that the introduction of auxiliary ligands to NHC-Pd complexes can provide new beneficial features in their catalytic activity [50,51,52,53]. We recently established [54] that a combination of er-NHC-Pd with phosphine ligand can efficiently catalyze the arylation both of primary and secondary amines to produce the corresponding triaryl amines. This finding has prompted us to investigate the double Buchwald–Hartwig coupling of NH₂-containing BTD compounds 4 with aryl bromides using a combination of the er-NHC-Pd complex with commercially available tert-butyl phosphine (protected as the BF₄ salt). Thus, we initially tested a catalytic activity of er-NHC-Pd/t-Bu₃P·HBF₄ (5/10 mol.%) in the model reaction of 4a with phenyl bromide. Fortunately, we revealed that the reaction smoothly proceeds in 1,4-dioxane at 110 °C in the presence of 3.0 equiv. of sodium tert-butoxide and goes to completion for 24 h, furnishing the desired N,N-diphenyl derivative 6a in excellent yield and selectivity. These conditions were further applied for the preparation of a series of the corresponding N,N-diarylated 5-amino-1,2,3-triazol-linked BTDs 6a–l in high yields (Scheme 5).

It is worth noting that this reaction demonstrates the first example of a double Buchwald–Hartwig cross-coupling reaction of 5-amino-1,2,3-triazoles with aryl halogenides.

Given the great value of electron–donor carbazole block in the development of advanced optoelectronic materials [55,56,57,58], as well as to be inspired by the results described above, we decided to study a possibility to perform one-pot diarylative cyclization of primary aminogroup of 4 with 2,2′-dibromobiaryls under found catalytic conditions.

As it was expected, the same catalytic system er-NHC-Pd/t-Bu₃P·HBF₄ (5/10 mol.%) has proved to be sufficiently active for the direct installation of a carbazole block into BTD derivatives 4a–d. The reactions have been accomplished under heating in dioxane solution in the presence of t-BuONa (3 equiv.), affording the desired products 7a–d in acceptable yields (Scheme 6).

All synthesized compounds isolated in analytically pure form via flash chromatography were fully characterized by means of standard physicochemical methods (see Supplementary Materials). In addition, single crystals of good quality were obtained from 6a, 6g, and 7a for X-ray analysis (Figure 1).

2.2. Optical and Electrochemical Investigation

We performed the initial estimation of photophysical properties of each type of the prepared compounds (4b, 5f, 6d, 6g, and 7a). Optical and electrochemical data are collected in Table 1.

All compounds exhibit intense absorption bands at the edge of the visible region (Figure 2). For all compounds except 6g, the absorption maxima are almost the same (scatter 404–407 nm). The compounds have strong emissions with maxima at 529–562 nm. Compounds 4b and 5f show significant quantum yields (86–89%), but the quantum yields of 6d and 7a are close to 100%, making them the most promising candidates for creating light-emitting OLED layers. Compound 6g has a reduced quantum yield compared to the rest of the series (although still substantial). The differences in the optical properties of 6g are clearly due to a change in the position of the triazole moiety in the benzene ring.

Voltammograms of the compounds are presented in ESI. All compounds show a reversible reduction in the region of −0.86 V relative to the selected reference silver chloride electrode. This similarity is due to the similar localization and energy of LUMO on the acceptor fragment of benzothiadiazole, common to all compounds. The irreversible oxidation of compounds is observed in the region of 1.2–1.5 V relative to the reference electrode. The differences are due to the different structures of donor substituents.

2.3. Electroluminescent Properties of 6d

Most of the synthesized compounds have a high photoluminescence quantum yield (PLQY) of over 80% in dichloromethane solution (DCM). Since compound 6d exhibits photoluminescence with the high PLQY of 95%, its electroluminescent properties were investigated in an OLED device with the following structure ITO/TAPC (53 nm)/TCTA (9 nm)/6d (15 wt.%):mCP (27 nm)/TPYMB (30 nm)/LiF (1 nm)/Al (80) nm. It contained a double-hole transport layer (HTL) consisting of 1,1-bis[(di-4-tolylamino) phenyl] cyclohexane (TAPC) and 4,4,4-tris(N-carbazolyl)triphenylamine (TCTA). The insertion of the thin layer of TCTA improved the hole-injection ability because of the step-wise hole injection from TAPC and TCTA to mCP (Figure 3), thereby ensuring a balance of charge carriers in the light-emitting layer (EML). In addition, it prevents the formation of exciplexes between the TAPC and the EML compounds [59].

Tris-(2,4,6-trimethyl-3-(pyridin-3-yl)phenyl) borane (3TPYMB) serves here as an electron transport layer (ETL), ITO is the anode and LiF/Al is the cathode. The light-emitting layer (EML) consists of a wide bandgap host material N,N-dicarbazolyl-3,5-benzene (mCP) and additive of dye 6d. EMLs with a dye content in the mCP matrix from 10 to 18 wt.% were investigated and optimal characteristics were obtained for OLED with a dye content of 15 wt.% (Table 2). All layers included in the OLED structures were formed using the method of thermal vacuum evaporation (TVE). OLED with EML based on pure 6d compound has also been produced. It demonstrated maximum brightness and a current efficiency two times lower than that of structures with co-deposited EML layers. Apparently, this is due to the concentration quenching of excited states.

The EL band of the device with a co-deposited 6d/mCP EML layer has a maximum at 555 nm (Figure 4a) and is shifted by 9 nm to longer wavelengths relative to the PL spectrum in a DCM solution (Table 1). The OLED emission color is green-white unsaturated and the CIE chromaticity coordinates do not lie on the locus boundary (Figure 4b) since the FWHM of the EL band is 79 nm. The broad PL and EL spectra arise as a result of charge transfer (CT) between the donor and acceptor fragments of dye 6d.

As can be clearly seen from Figure 3, the HOMO and LUMO energy levels of compound 6d measured by CVA are well matched to the levels of mCP, which provides a balanced injection of electrons and holes into the EML and the onset voltage does not exceed 4 V. Since the HOMO levels of 6d and mCP are very close to each other, the 6d molecules are shallow traps and do not interfere with the transport of holes in the light-emitting layer. The maximum brightness of an OLED with the EML layer of 6d/mCP reaches 8000 cd/m² at an applied voltage of 18 V (Figure 5). The maximum current efficiency of the device reaches a value of 3.29 cd/A (Table 2).

3. Materials and Methods

3.1. General Information

All reagents were used as purchased from Sigma-Aldrich (Munich, Germany). BTD 1 [33], (THP-Dipp)Pd(cinn)Cl [60], aryl azides [61], benzyl azide, and (3-azidoprop-1-enyl)benzene [62], 2-(azidoethyl)benzene [63], 2,2’-dibromobiphenyl, and 2,2’-dibromo-4,4’,5,5’-tetramethoxybiphenyl [54] were synthesized according to published procedures. Analytical data were in accordance with the literature data. Analytical TLC was performed with Merck silica gel 60 F 254 plates (Darmstadt, Germany); visualization was accomplished with UV light or iodine vapors. Chromatography was carried out using Merck silica gel (Kieselgel 60, 0.063–0.200 mm) and petroleum ether/ethyl acetate as an eluent. The ¹H and ¹³C NMR spectra were recorded on a Varian Inova 400 spectrometer (Varian, Palo Alto, CA, USA) operating at 400 and 101 MHz, respectively. Chemical shifts are given in ppm using residual solvent signals as internal standards. High-resolution mass spectra were recorded on an LCMS-9030 device (Shimadzu, Japan) by electrospray ionization–mass spectrometry (ESI-MS).

3.2. Preparation and Characterization of Starting Compounds 2, 3a and 3b

• 4-(4-Methoxyphenyl)-7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzo[c][1,2,5]thiadiazole (2). Under argon in a Schlenk tube with a magnetic stirring bar, 1 (321 mg, 1.0 mmol, 1.0 equiv.), KOAc (294 mg, 3.0 mmol, 3 equiv.) and bis(pinacolato)diboron (279 mg, 1.1 mmol, 1.1 equiv.) were added followed by dry dioxane (15 mL). The solution was degassed by argon before adding PdCl₂(dppf) (14 mg, 0.02 equiv.). Then, the reaction mixture was stirred at 95 °C (oil bath temperature) for 24 h. After cooling to room temperature, the mixture was poured into water and extracted with dichloromethane (3 × 10 mL). The combined organic phases were washed with brine, dried over anhydrous MgSO₄, filtered, and concentrated under reduced pressure. Purification by chromatography (eluent–hexane: ethyl acetate 5:1) gave 2 (233 mg, 63%) as a white solid. ¹H NMR (400 MHz, chloroform-d) δ 8.23 (d, J = 7.0 Hz, 1H), 7.91 (d, J = 8.3 Hz, 2H), 7.64 (d, J = 7.0 Hz, 1H), 7.04 (d, J = 8.3 Hz, 2H), 3.86 (s, 3H), 1.44 (s, 12H). ¹³C NMR (101 MHz, chloroform-d) δ 160.1, 158.2, 153.4, 139.3, 136.9, 130.7, 129.8, 126.3, 114.1, 84.3, 55.4, 25.0, missing one carbon (C-B) due to interaction with the boron atom. HRMS (ESI) of C₁₉H₂₁BN₂O₃S, m/z: calcd for [M+H]⁺: 369.1442, found: 369.1448.

• 2-(4-(7-(4-Methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)acetonitrile (3a). The title compound was synthesized according to the literature procedure [33] from 1 and 2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)acetonitrile as a yellow solid (67% yield). ¹H NMR (400 MHz, chloroform-d) δ 7.98 (d, J = 8.3 Hz, 2H), 7.94 (d, J = 8.9 Hz, 2H), 7.75 (d, J = 4.1 Hz, 2H), 7.51 (d, J = 8.4 Hz, 2H), 7.09 (d, J = 8.9 Hz, 2H), 3.90 (s, 3H), 3.85 (s, 2H). ¹³C NMR (101 MHz, chloroform-d) δ 160.1, 154.3, 154.1, 137.5, 133.6, 131.7, 130.6, 130.0, 129.9, 128.4, 128.3, 127.3, 117.8, 114.3, 110.1, 55.5, 23.6. HRMS (ESI) of C₂₁H₁₅N₃OS, m/z: calcd for [M+H]⁺ 358.1008, found: 358.1009.

• 2-(2-(7-(4-Methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)acetonitrile (3b). The title compound was synthesized according to the literature procedure [33] from 2 and 2-(2-bromophenyl)acetonitrile as a yellow solid (66% yield). ¹H NMR (400 MHz, chloroform-d) δ 7.96 (d, J = 8.7 Hz, 2H), 7.77 (d, J = 7.2 Hz, 1H), 7.68 (d, J = 7.6 Hz, 1H), 7.63 (d, J = 7.2 Hz, 1H), 7.54 (t, J = 7.5 Hz, 1H), 7.49 (t, J = 7.2 Hz, 1H), 7.44 (d, J = 7.3 Hz, 1H), 7.11 (d, J = 8.7 Hz, 2H), 3.91 (s, 3H), 3.66 (s, 2H). ¹³C NMR (101 MHz, chloroform-d) δ 160.2, 154.3, 153.7, 137.4, 134.3, 131.3, 131.3, 130.7, 130.5, 129.6, 129.4, 129.2, 129.1, 128.5, 127.1, 118.1, 114.3, 55.6, 22.7. HRMS (ESI) of C₂₁H₁₅N₃OS, m/z: calcd for [M+H]⁺ 358.1009, found: 358.1005.

3.3. Preparation and Characterization of Novel Compounds

3.3.1. General Procedure A for Preparation of BTD-Containing 5-Amino-1,2,3-triazoles 4a–g via Dipolar Azide–Nitrile Cycloaddition (DCR)

A 25 mL round-bottom flask, equipped with a magnetic stir bar was charged with 3 mmol of 3a or 3b, 3.0 equiv. of corresponding azide, DMSO (8 mL). The resulting mixture was placed into a water bath (room temperature) and 0.5 equiv. of powdered potassium tert-butoxide was added portionwise. The reaction mixture was allowed to stir for 3 h at 70 °C. Upon completion, the mixture was poured into water and extracted with dichloromethane (3 × 10 mL). The combined organic phases were washed with brine, dried over MgSO₄, filtered, and concentrated under reduced pressure. Purification by chromatography (eluent–hexane: ethyl acetate 1:1) yielded an analytically pure product.

• 1-Benzyl-4-(4-(7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-1H-1,2,3-triazol-5-amine (4a). Compound 4a was synthesized according to the general procedure A (yield 94%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 8.00 (d, J = 8.2 Hz, 2H), 7.89 (d, J = 8.7 Hz, 2H), 7.79 (d, J = 8.2 Hz, 2H), 7.75 (d, J = 7.4 Hz, 1H), 7.69 (d, J = 7.2 Hz, 1H), 7.39–7.31 (m, 4H), 7.24 (d, J = 5.4 Hz, 1H), 7.05 (d, J = 8.5 Hz, 2H), 5.45 (s, 2H), 3.86 (s, 3H), 3.76 (s, 2H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.3, 154.2, 137.7, 136.1, 134.2, 133.1, 132.1, 131.6, 130.6, 130.0, 129.9 (d, J = 7.8 Hz), 129.4, 128.8, 128.2, 127.4, 127.4, 125.8, 114.2, 55.5, 50.9. HRMS (ESI) of C₂₈H₂₃N₆OS, m/z: calcd for [M+H]⁺ 491.1649, found: 491.1652.

• 4-(4-(7-(4-Methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-1-phenethyl-1H-1,2,3-triazol-5-amine (4b). Compound 4b was synthesized according to the general procedure A (yield 64%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 8.03 (d, J = 8.5 Hz, 2H), 7.94 (d, J = 8.8 Hz, 2H), 7.82–7.74 (m, 4H), 7.31 (q, J = 5.9 Hz, 3H), 7.14–7.08 (m, 4H), 4.46 (t, J = 6.6 Hz, 2H), 3.91 (s, 3H), 3.24 (t, J = 6.5 Hz, 2H), 3.09 (s, 2H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.3, 154.2, 138.0, 137.8, 136.1, 133.1, 132.2, 131.8, 131.0, 130.6, 130.0, 129.8, 129.2, 129.1, 128.2, 127.4, 126.0, 114.3, 55.5, 48.4, 36.5. HRMS (ESI) of C₂₉H₂₄N₆OS, m/z: calcd for [M+H]⁺ 505.1805, found: 505.1806.

• 1-Cinnamyl-4-(4-(7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-1H-1,2,3-triazol-5-amine (4c). Compound 4c was synthesized according to the general procedure A (yield 62%) as a red solid. ¹H NMR (400 MHz, chloroform-d) δ 8.07 (d, J = 8.3 Hz, 2H), 7.94 (d, J = 8.8 Hz, 2H), 7.87 (d, J = 8.3 Hz, 2H), 7.81 (d, J = 7.3 Hz, 1H), 7.76 (s, 1H), 7.41–7.38 (m, 2H), 7.36–7.33 (m, 2H), 7.32–7.30 (m, 1H), 7.09 (d, J = 8.8 Hz, 2H), 6.65 (d, J = 15.9 Hz, 1H), 6.40–6.34 (m, 1H), 5.10 (d, J = 6.2 Hz, 2H), 4.00 (s, 2H), 3.90 (s, 3H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.3, 154.2, 137.9, 136.2, 135.5, 134.4, 133.1, 132.2, 131.7, 131.0, 130.6, 130.0, 129.9, 128.9, 128.7, 128.2, 127.5, 126.8, 125.9, 121.9, 114.3, 55.5, 49.4. HRMS (ESI) of C₃₀H₂₄N₆OS, m/z: calcd for [M+H]₊ 517.1805, found: 517.1807.

• 1-(4-Methoxyphenyl)-4-(4-(7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-1H-1,2,3-triazol-5-amine (4d). Compound 4d was synthesized according to the general procedure A (yield 81%) as a red solid. ¹H NMR (400 MHz, DMSO-d₆) δ 8.11 (d, J = 8.4 Hz, 2H), 8.00 (t, J = 7.9 Hz, 5H), 7.91 (d, J = 7.2 Hz, 1H), 7.54 (d, J = 8.6 Hz, 2H), 7.20–7.10 (m, 4H), 5.83 (s, 2H), 3.86 (s, 6H). ¹³C NMR (101 MHz, DMSO-d₆) δ 159.6, 159.5, 153.5, 153.4, 139.7, 134.2, 132.6, 132.0, 131.7, 131.2, 130.3, 129.3, 129.2, 129.2, 129.0, 128.0, 128.80, 127.6, 127.5, 126.6, 124.7, 55.6, 55.3. HRMS (ESI) of C₂₈H₂₂N₆O₂S, m/z: calcd for [M+H]⁺ 507.1598, found: 507.1593.

• 4-(4-(7-(4-Methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-1-p-tolyl-1H-1,2,3-triazol-5-amine (4e). Compound 4e was synthesized according to the general procedure A (yield 75%) as a red solid. ¹H NMR (400 MHz, chloroform-d) δ 8.08 (d, J = 7.8 Hz, 2H), 7.93 (t, J = 6.6 Hz, 4H), 7.81 (d, J = 7.2 Hz, 1H), 7.74 (d, J = 7.4 Hz, 1H), 7.50 (d, J = 7.8 Hz, 2H), 7.38 (d, J = 7.8 Hz, 2H), 7.09 (d, J = 8.2 Hz, 2H), 4.15 (s, 2H), 3.90 (s, 3H), 2.46 (s, 3H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.3, 154.2, 139.9, 137.9, 136.0, 133.1, 132.6, 132.1, 131.6, 130.6, 130.6, 129.9, 129.4, 128.2, 127.5, 125.7, 124.5, 114.2, 110.2, 55.5, 21.4. HRMS (ESI) of C₂₈H₂₃N₆OS, m/z: calcd for [M+H]⁺ 491.1649, found: 491.1654.

• 1-Benzyl-4-(2-(7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-1H-1,2,3-triazol-5-amine (4f). Compound 4f was synthesized according to the general procedure A (yield 84%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 7.85 (d, J = 8.5 Hz, 2H), 7.70 (d, J = 8.5 Hz, 1H), 7.64 (d, J = 8.5 Hz, 1H), 7.53 (d, J = 5.2 Hz, 3H), 7.48 (d, J = 7.4 Hz, 1H), 7.19 (d, J = 4.8 Hz, 3H), 7.08 (d, J = 8.6 Hz, 2H), 6.87 (d, J = 7.4 Hz, 2H), 5.19 (s, 2H), 3.91 (s, 3H), 2.83 (s, 2H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.4, 153.7, 137.4, 136.7, 134.1, 133.0, 132.3, 131.3, 131.0, 130.6, 130.5, 130.3, 129.7, 129.2, 128.9, 128.4, 128.4, 127.2, 126.9, 114.2, 55.5, 50.6. HRMS (ESI) of C₂₈H₂₂N₆OS, m/z: calcd for [M+H]⁺ 491.1649, found: 491.1644.

• 4-(2-(7-(4-Methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-1-p-tolyl-1H-1,2,3-triazol-5-amine (4g). Compound 4g was synthesized according to the general procedure A (yield 71%) as a red solid. ¹H NMR (400 MHz, chloroform-d) δ 7.91 (d, J = 7.1 Hz, 2H), 7.76 (d, J = 7.0 Hz, 1H), 7.68 (d, J = 7.0 Hz, 1H), 7.62 (dd, J = 7.3, 1.5 Hz, 1H), 7.59–7.53 (m, 3H), 7.21 (d, J = 7.5 Hz, 2H), 7.15 (d, J = 6.9 Hz, 2H), 7.06 (d, J = 7.2 Hz, 2H), 3.88 (s, 3H), 3.33 (s, 2H), 2.35 (s, 3H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.6, 153.9, 139.4, 137.7, 136.9, 133.1, 132.7, 132.4, 131.5, 130.9, 130.6, 130.4, 129.8, 128.9, 128.4, 127.3, 124.0, 114.2, 55.5, 21.3. HRMS (ESI) of C₂₈H₂₃N₆OS, m/z: calcd for [M+H]⁺ 491.1649, found: 491.1645.

3.3.2. General Procedure B for Preparation of N-Monosubstituted Arylamino-1,2,3-triazole- 2,1,3-Benzothiadiazoles 5a–f via BHA Reaction

A screw-cap vial equipped with a magnetic stir bar charged with 0.2 mmol of 4 and (het)arylbromide (5.0 equiv.), dry 1,4-dioxane (1.0 mL), (THP-Dipp)Pd(cinn)Cl (5 mol%), and sodium tert-butoxide (3.0 equiv.) was replaced into a preheated oil bath 110 °C and allowed to stir for 18 h at this temperature. After cooling to room temperature, the reaction mixture was poured into water and extracted with dichloromethane (3 × 10 mL). The combined organic phases were washed with brine, dried over MgSO₄, filtered, and concentrated under reduced pressure. Purification by chromatography (eluent–hexane: ethyl acetate 2:1) yielded an analytically pure product.

• 1-Benzyl-4-(4-(7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-N-phenyl-1H-1,2,3-triazol-5-amine (5a). Compound 5a was synthesized according to the general procedure B (yield 91%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 7.99 (d, J = 8.2 Hz, 2H), 7.95–7.88 (m, 4H), 7.73 (d, J = 7.4 Hz, 1H), 7.69 (d, J = 7.4 Hz, 1H), 7.35–7.28 (m, 3H), 7.25–7.17 (m, 4H), 7.07 (d, J = 8.7 Hz, 2H), 6.90 (t, J = 7.4 Hz, 1H), 6.57 (d, J = 7.9 Hz, 2H), 5.39 (s, 2H), 5.18 (s, 1H), 3.89 (s, 3H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.3, 154.1, 143.6, 140.9, 137.1, 134.7, 133.2, 132.1, 131.8, 130.6, 130.2, 130.0, 129.6, 129.1, 128.6, 128.2, 128.0, 127.4, 126.1, 120.8, 114.3, 114.2, 55.5, 51.6. HRMS (ESI) of C₃₄H₂₆N₆OS, m/z: calcd for [M+H]⁺ 567.1962, found: 567.1962.

• 1-Benzyl-4-(4-(7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-N-o-tolyl-1H-1,2,3-triazol-5-amine (5b). Compound 5b was synthesized according to the general procedure B (yield 61%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 7.97 (d, J = 2.3 Hz, 4H), 7.92 (d, J = 8.6 Hz, 2H), 7.76 (d, J = 7.5 Hz, 1H), 7.71 (d, J = 7.3 Hz, 1H), 7.33–7.30 (m, 3H), 7.18 (t, J = 7.6 Hz, 3H), 7.07 (d, J = 8.6 Hz, 2H), 7.02 (t, J = 8.6 Hz, 1H), 6.86 (t, J = 7.5 Hz, 1H), 6.32 (d, J = 8.0 Hz, 1H), 5.37 (s, 2H), 4.87 (s, 1H), 3.89 (s, 3H), 2.17 (s, 3H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.3, 154.1, 141.5, 140.7, 137.1, 134.7, 133.2, 132.1, 131.1, 130.6, 130.3, 130.0, 129.6, 129.1, 128.6, 128.2, 127.9, 127.7, 127.4, 126.1, 123.4, 120.9, 114.3, 112.9, 55.6, 51.8, 17.5. HRMS (ESI) of C₃₅H₂₈N₆OS, m/z: calcd for [M+H]⁺ 581.2118, found: 581.2117.

• 1-Benzyl-4-(4-(7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-N-p-tolyl-1H-1,2,3-triazol-5-amine (5c). Compound 5c was synthesized according to the general procedure B (yield 88%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 8.02 (d, J = 8.3 Hz, 2H), 7.96 (d, J = 8.4 Hz, 2H), 7.92 (d, J = 8.6 Hz, 2H), 7.76 (d, J = 7.4 Hz, 1H), 7.72 (d, J = 7.4 Hz, 1H), 7.32 (dd, J = 4.8, 1.8 Hz, 3H), 7.22 (dd, J = 6.5, 2.8 Hz, 2H), 7.08 (d, J = 8.6 Hz, 2H), 7.03 (d, J = 8.1 Hz, 2H), 6.50 (d, J = 8.2 Hz, 2H), 5.39 (s, 2H), 4.95 (s, 1H), 3.89 (s, 3H), 2.28 (s, 3H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.3, 154.1, 141.2, 140.6, 137.0, 134.8, 133.1, 132.3, 132.1, 130.5, 130.4, 129.5, 129.0, 128.5, 128.2, 128.0, 127.4, 126.1, 120.7, 114.4, 114.2, 55.5, 51.5, 20.6. HRMS (ESI) of C₃₅H₂₈N₆OS, m/z: calcd for [M+H]⁺ 581.2118, found: 581.2114.

• N-(1-Benzyl-4-(4-(7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-1H-1,2,3-triazol-5-yl)pyridin-3-amine (5d). Compound 5d was synthesized according to the general procedure B (yield 55%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 8.06 (s, 2H), 7.91–7.86 (m, 5H), 7.66–7.62 (m, 2H), 7.54–7.43 (m, 1H), 7.25–7.21 (m, 3H), 7.19 (s, 2H), 7.05 (d, J = 8.5 Hz, 2H), 7.00–6.95 (m, 1H), 6.58 (d, J = 8.3 Hz, 1H), 6.16 (s, 1H), 5.41 (s, 2H), 3.88 (s, 3H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.2, 154.0, 141.4, 141.1, 140.4, 137.3, 136.9, 134.3, 133.2, 132.1, 131.8, 130.7, 130.6, 129.7, 129.6, 129.1, 128.7, 128.3, 128.0, 127.3, 126.1, 124.2, 120.4, 114.2, 55.5, 51.8. HRMS (ESI) of C₃₃H₂₅N₇OS, m/z: calcd for [M+H]⁺ 568.1914, found: 568.1906.

• 1-Benzyl-N-(4-methoxyphenyl)-4-(4-(7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-1H-1,2,3-triazol-5-amine (5e). Compound 5e was synthesized according to the general procedure B (yield 59%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 8.01–7.93 (m, 4H), 7.91 (d, J = 8.7 Hz, 2H), 7.74 (d, J = 7.4 Hz, 1H), 7.69 (d, J = 7.3 Hz, 1H), 7.32–7.29 (m, 3H), 7.21 (dd, J = 6.8, 2.8 Hz, 2H), 7.07 (d, J = 8.6 Hz, 2H), 6.77 (d, J = 8.8 Hz, 2H), 6.53 (d, J = 8.8 Hz, 2H), 5.38 (s, 2H), 5.05 (s, 1H), 3.89 (s, 3H), 3.75 (s, 3H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.4, 154.3, 154.1, 140.2, 137.1, 137.1, 134.7, 133.2, 132.9, 132.1, 130.6, 130.0, 129.6, 129.0, 128.6, 128.2, 128.0, 127.4, 126.2, 116.0, 115.3, 114.3, 55.8, 55.5, 51.6. HRMS (ESI) of C₃₅H₂₈N₆O₂S, m/z: calcd for [M+H]⁺ 597.2067, found: 597.2064.

• 4-(4-(7-(4-Methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-1-phenethyl-N-p-tolyl-1H-1,2,3-triazol-5-amine (5f). Compound 5f was synthesized according to the general procedure B (yield 53%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 7.96–7.90 (m, 6H), 7.72 (q, J = 7.4 Hz, 2H), 7.34–7.30 (m, 3H), 7.08 (d, J = 8.8 Hz, 2H), 7.06–7.03 (m, 2H), 6.98 (d, J = 8.0 Hz, 2H), 6.33 (d, J = 8.4 Hz, 2H), 4.40 (t, J = 6.8 Hz, 2H), 4.21 (s, 1H), 3.89 (s, 3H), 3.20 (t, J = 6.8 Hz, 2H), 2.24 (s, 3H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.3, 154.1, 141.2, 140.1, 138.0, 136.9, 133.1, 132.5, 132.2, 130.6, 130.4, 130.4, 130.0, 129.9, 129.5, 129.2, 129.0, 128.2, 127.4, 127.4, 126.2, 114.2, 114.1, 55.5, 48.9, 36.8, 20.6. HRMS (ESI) of C₃₆H₃₀N₆OS, m/z: calcd for [M+H]⁺ 595.2275, found: 595.2272.

3.3.3. General Procedure C for Preparation N,N-Disubstituted-arylamino-1,2,3-triazole- 2,1,3-Benzothiadiazoles 6a–l and 7a–d via BHA Reaction

A screw-cap vial equipped with a magnetic stir bar was charged with 0.2 mmol of 4, corresponding aryl-Br (5 equiv.) or 2,2′-dibromobiphenyl (1.0 equiv.), dry 1,4-dioxane (1.0 mL), (THP-Dipp)Pd(cinn)Cl (5 mol%), t-Bu₃-HBF₄ (10 mol.%), and sodium tert-butoxide (3.0 equiv.) was replaced into a preheated oil bath 110 °C (or 150 °C for solvent-free procedure) and allowed to stir for 18 h at this temperature. After cooling to room temperature, the reaction mixture was poured into water and extracted with dichloromethane (3 × 10 mL). The combined organic phases were washed with brine, dried over MgSO₄, filtered, and concentrated under reduced pressure. Purification by chromatography (eluent–hexane: ethyl acetate 2:1) yielded an analytically pure product.

• 1-Benzyl-4-(4-(7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-N,N-diphenyl-1H-1,2,3-triazol-5-amine (6a). Compound 6a was synthesized according to the general procedure C (yield 96%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 8.0–7.9 (m, 3H), 7.9–7.9 (m, 3H), 7.7 (d, J = 4.0 Hz, 2H), 7.2–7.2 (m, 3H), 7.2–7.1 (m, 6H), 7.1 (d, J = 8.8 Hz, 2H), 7.0 (t, J = 7.4 Hz, 2H), 6.9 (d, J = 7.6 Hz, 4H), 5.2 (s, 2H), 3.9 (s, 3H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.3, 154.1, 143.9, 140.6, 137.0, 135.5, 134.3, 133.1, 132.1, 130.5, 130.0, 129.7, 129.3, 129.1, 128.8, 128.4, 128.2, 127.4, 126.1, 123.5, 120.7, 114.2, 55.5, 51.8. HRMS (ESI) of C₄₀H₃₀N₆OS, m/z: calcd for [M+H]⁺ 643.2275, found: 643.2275.

• 4-(4-(7-(4-Methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-N,N-diphenyl-1-p-tolyl-1H-1,2,3-triazol-5-amine (6b). Compound 6b was synthesized according to the general procedure C (yield 67%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 8.06 (d, J = 8.4 Hz, 2H), 7.94–7.89 (m, 4H), 7.73 (d, J = 7.4 Hz, 1H), 7.69 (d, J = 7.3 Hz, 1H), 7.25–7.23 (m, 2H), 7.17 (t, J = 7.9 Hz, 4H), 7.10 (d, J = 8.2 Hz, 2H), 7.06 (d, J = 8.7 Hz, 2H), 6.97 (d, J = 8.3 Hz, 6H), 3.87 (s, 3H), 2.32 (s, 3H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.3, 154.1, 144.2, 140.6, 139.7, 137.2, 135.7, 133.2, 133.2, 132.1, 130.6, 130.0, 129.8, 129.6, 129.5, 128.3, 127.4, 126.2, 124.5, 123.4, 120.7, 114.2, 55.5, 21.3. HRMS (ESI) of C₄₀H₃₀N₆OS, m/z: calcd for [M+H]+ 643.2275, found: 643.2267; calcd for [M+Na]⁺ 665.2094, found: 665.2092.

• 1-(4-Methoxyphenyl)-4-(4-(7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-N,N-diphenyl-1H-1,2,3-triazol-5-amine (6c). Compound 6c was synthesized according to the general procedure C (yield 62%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 8.06 (d, J = 8.1 Hz, 2H), 7.95–7.90 (m, 4H), 7.76–7.69 (m, 2H), 7.25 (s, 2H), 7.18 (t, J = 7.8 Hz, 4H), 7.07 (d, J = 8.4 Hz, 2H), 6.96 (d, J = 7.6 Hz, 6H), 6.80 (d, J = 8.5 Hz, 2H), 3.88 (s, 3H), 3.78 (s, 3H). ¹³C NMR (101 MHz, chloroform-d) δ 160.4, 160.0, 154.3, 144.2, 137.2, 135.9, 132.1, 130.6, 130.0, 129.7, 129.5, 128.3, 127.4, 126.3, 126.1, 123.4, 120.7, 114.4, 114.3, 55.7, 55.6. HRMS (ESI) of C₄₀H₃₀N₆O₂S, m/z: calcd for [M+H]⁺ 659.2224, found: 659.2224.

• 4-(4-(7-(4-Methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-1-phenethyl-N,N-diphenyl-1H-1,2,3-triazol-5-amine (6d). Compound 6d was synthesized according to the general procedure C (yield 83%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 7.98 (d, J = 8.5 Hz, 2H), 7.93–7.87 (m, 4H), 7.70 (q, J = 7.3 Hz, 2H), 7.28–7.20 (m, 8H), 7.06 (d, J = 8.9 Hz, 2H), 7.01 (d, J = 8.5 Hz, 7H), 4.29–4.22 (t, J = 7.6 Hz, 2H), 3.87 (s, 3H), 3.02–2.93 (t, J = 7.5 Hz, 2H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.3, 154.1, 144.2, 140.4, 137.2, 137.1, 135.4, 133.1, 132.1, 130.5, 129.9, 129.7, 129.4, 129.0, 128.8, 128.2, 127.4, 127.0, 126.0, 123.6, 120.6, 114.2, 55.5, 49.1, 35.6. HRMS (ESI) of C₄₁H₃₂N₆OS, m/z: calcd for [M+H]⁺ 657.2431, found: 657.2433; calcd for [M+K]⁺ 695.1990, found: 695.1990.

• 1-Benzyl-4-(4-(7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-N,N-di(p-tolyl)-1H-1,2,3-triazol-5-amine (6e). Compound 6e was synthesized according to the general procedure C (yield 97%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 7.91 (dt, J = 24.0, 8.4 Hz, 7H), 7.70 (d, J = 4.3 Hz, 2H), 7.24–7.22 (m, 2H), 7.16 (t, J = 4.0 Hz, 2H), 7.07 (d, J = 8.8 Hz, 2H), 6.96 (d, J = 8.2 Hz, 4H), 6.78 (d, J = 8.2 Hz, 4H), 5.22 (s, 2H), 3.89 (s, 3H), 2.24 (s, 6H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.3, 154.1, 141.7, 140.3, 136.9, 135.8, 134.5, 133.0, 132.8, 132.2, 130.5, 130.2, 129.2, 128.7, 128.4, 128.3, 128.1, 127.4, 126.1, 120.6, 114.2, 55.5, 51.7, 20.8. HRMS (ESI) of C₄₂H₃₄N₆OS, m/z: calcd for [M+H]⁺ 671.2588, found: 671.2584; calcd for [M+Na]+ 693.2407, found: 693.2405.

• 4-(4-(7-(4-Methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-N,N,1-tri(p-tolyl)-1H-1,2,3-triazol-5-amine (6f). Compound 6f was synthesized according to the general procedure C (yield 67%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 8.08 (d, J = 8.2 Hz, 2H), 7.95–7.91 (m, 4H), 7.76 (d, J = 7.6 Hz, 1H), 7.71 (d, J = 7.5 Hz, 1H), 7.28 (d, J = 8.7 Hz, 2H), 7.12 (d, J = 8.1 Hz, 2H), 7.09 (s, 2H), 6.97 (d, J = 8.5 Hz, 4H), 6.85 (d, J = 8.1 Hz, 4H), 3.90 (s, 3H), 2.34 (s, 3H), 2.24 (s, 6H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.3, 154.1, 141.9, 139.5, 137.1, 135.9, 133.4, 133.1, 132.7, 130.6, 130.2, 129.8, 129.7, 129.5, 128.3, 127.4, 126.2, 124.4, 120.5, 114.3, 110.2, 109.9, 55.6, 21.4, 20.8. HRMS (ESI) of C₄₂H₃₄N₆OS, m/z: calcd for [M+H]⁺ 671.2588, found: 671.2580.

• 1-Benzyl-4-(2-(7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-N,N-diphenyl-1H-1,2,3-triazol-5-amine (6g). Compound 6g was synthesized according to the general procedure C (yield 67%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 7.94 (d, J = 8.7 Hz, 2H), 7.60 (d, J = 7.2 Hz, 1H), 7.50 (d, J = 7.9 Hz, 1H), 7.44 (d, J = 7.2 Hz, 1H), 7.31 (d, J = 7.7 Hz, 1H), 7.24 (d, J = 5.9 Hz, 3H), 7.10 (d, J = 8.8 Hz, 3H), 7.01–6.97 (m, 3H), 6.80 (t, J = 7.5 Hz, 4H), 6.76–6.71 (m, 2H), 6.10 (d, J = 7.8 Hz, 4H), 4.96 (s, 2H), 3.91 (s, 3H). ¹³C NMR (101 MHz, chloroform-d) δ 159.9, 154.9, 154.0, 143.8, 141.8, 138.1, 136.7, 134.6, 132.9, 132.4, 131.2, 130.6, 130.5, 130.1, 129.4, 128.5, 128.4, 128.2, 127.7, 123.2, 123.1, 120.9, 120.8, 114.3, 55.5, 52.3. HRMS (ESI) of C₄₀H₃₀N₆OS, m/z: calcd for [M+H]⁺ 643.2275, found: 643.2273.

• 4-(2-(7-(4-Methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-N,N-diphenyl-1-p-tolyl-1H-1,2,3-triazol-5-amine (6h). Compound 6h was synthesized according to the general procedure C (yield 71%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 7.93 (d, J = 8.9 Hz, 2H), 7.63 (d, J = 7.3 Hz, 1H), 7.58–7.52 (m, 3H), 7.39 (d, J = 6.4 Hz, 1H), 7.22 (d, J = 8.3 Hz, 3H), 7.09 (d, J = 8.6 Hz, 2H), 6.98 (d, J = 8.2 Hz, 2H), 6.86 (t, J = 7.6 Hz, 4H), 6.74 (t, J = 7.3 Hz, 2H), 6.45 (d, J = 7.9 Hz, 4H), 3.90 (s, 3H), 2.22 (s, 3H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 155.0, 154.0, 144.0, 141.9, 139.0, 138.0, 133.5, 133.0, 132.6, 131.2, 131.1, 130.6, 130.1, 129.6, 129.3, 128.8, 128.4, 127.9, 126.9, 123.3, 123.0, 120.8, 114.3, 55.6, 21.2. HRMS (ESI) of C₄₀H₃₀N₆OS, m/z: calcd for [M+H]⁺ 643.2275, found: 643.2271.

• 1-Benzyl-N,N-bis(4-methoxyphenyl)-4-(4-(7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-1H-1,2,3-triazol-5-amine (6i). Compound 6i was synthesized according to the general procedure C (yield 98%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 7.94–7.86 (m, 7H), 7.70 (d, J = 5.6 Hz, 2H), 7.25–7.24 (m, 2H), 7.18–7.15 (m, 2H), 7.07 (d, J = 9.0 Hz, 2H), 6.79 (d, J = 9.0 Hz, 4H), 6.69 (d, J = 9.1 Hz, 4H), 5.23 (s, 2H), 3.88 (s, 3H), 3.72 (s, 6H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 155.6, 154.3, 154.1, 140.1, 137.8, 136.9, 136.1, 134.6, 133.0, 132.2, 130.5, 130.0, 129.8, 129.2, 128.8, 128.3, 128.3, 128.1, 127.4, 126.1, 121.9, 114.9, 114.2, 110.1, 55.6, 55.5, 51.7. HRMS (ESI) of C₄₂H₃₄N₆O₃S, m/z: calcd for [M+H]⁺ 703.2486, found: 703.2480; calcd for [M+K]⁺ 741.2045, found: 741.2051.

• 1-Benzyl-N,N-bis(4-tert-butylphenyl)-4-(4-(7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-1H-1,2,3-triazol-5-amine (6j). Compound 6j was synthesized according to the general procedure C (yield 64%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 7.97 (d, J = 8.4 Hz, 2H), 7.91 (d, J = 8.7 Hz, 2H), 7.87 (d, J = 8.3 Hz, 2H), 7.70 (d, J = 2.5 Hz, 2H), 7.17 (dd, J = 7.6, 4.1 Hz, 6H), 7.06 (t, J = 7.0 Hz, 4H), 6.87 (d, J = 8.6 Hz, 4H), 5.27 (s, 2H), 3.89 (s, 3H), 1.26 (s, 18H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.3, 154.1, 146.1, 141.6, 140.5, 136.9, 135.8, 134.3, 133.1, 132.3, 130.6, 130.0, 129.9, 129.3, 128.7, 128.4, 128.2, 128.1, 127.4, 126.4, 126.1, 55.5, 51.4, 34.4, 31.5. HRMS (ESI) of C₄₈H₄₆N₆OS, m/z: calcd for [M+H]⁺ 755.3527, found: 755.3534; calcd for [M+Na]⁺ 777.3346, found: 777.3333; calcd for [M+K]⁺ 793.3086, found: 793.3090.

• N1-(1-Benzyl-4-(4-(7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-1H-1,2,3-triazol-5-yl)-N1-(4-(dimethylamino)phenyl)-N4,N4-dimethylbenzene-1,4-diamine (6k). Compound 6k was synthesized according to the general procedure C (yield 65%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 7.96 (d, J = 8.5 Hz, 2H), 7.91 (d, J = 8.8 Hz, 2H), 7.86 (d, J = 8.3 Hz, 2H), 7.70 (d, J = 5.2 Hz, 2H), 7.26–7.24 (m, 3H), 7.20–7.18 (m, 2H), 7.07 (d, J = 8.8 Hz, 2H), 6.76 (d, J = 9.0 Hz, 4H), 6.55 (d, J = 8.9 Hz, 4H), 5.22 (s, 2H), 3.89 (s, 3H), 2.86 (s, 12H). ¹³C NMR (101 MHz, chloroform-d) δ 159.9, 154.3, 154.1, 146.9, 139.8, 136.6, 135.1, 134.9, 132.9, 132.4, 130.5, 130.1, 130.0, 129.2, 128.7, 128.5, 128.2, 128.1, 127.4, 126.2, 121.8, 114.2, 113.9, 55.5, 51.5, 41.2. HRMS (ESI) of C₄₄H₄₀N₈OS, m/z: calcd for [M]⁺ 728.3046, found: 728.3035.

• 1-Benzyl-N,N-bis(3,5-dimethylphenyl)-4-(4-(7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-1H-1,2,3-triazol-5-amine (6l). Compound 6l was synthesized according to the general procedure C (yield 58%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 7.98 (d, J = 8.4 Hz, 2H), 7.93–7.87 (m, 4H), 7.74–7.69 (m, 2H), 7.26–7.23 (m, 3H), 7.20–7.17 (m, 2H), 7.07 (d, J = 8.8 Hz, 2H), 6.59 (s, 2H), 6.49 (s, 4H), 5.23 (s, 2H), 3.89 (s, 3H), 2.14 (s, 12H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.3, 154.1, 144.1, 140.5, 139.3, 139.2, 136.9, 135.9, 134.5, 133.1, 132.3, 130.5, 130.0, 129.9, 129.2, 128.7, 128.5, 128.4, 128.2, 127.4, 126.2, 125.2, 118.8, 114.2, 55.5, 51.7, 21.5. HRMS (ESI) of C₃₅H₂₈N₆O₂S, m/z: calcd for [M+H]⁺ 699.2901, found: 699.2896; calcd for [M+Na]⁺ 721.2720, found: 721.2714.

• 4-(4-(1-Benzyl-5-(9H-carbazol-9-yl)-1H-1,2,3-triazol-4-yl)phenyl)-7-(4-methoxyphenyl) benzo[c][1,2,5]thiadiazole (7a). Compound 7a was synthesized according to the general procedure C (yield 54%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 8.14 (d, J = 7.6 Hz, 2H), 7.88 (d, J = 8.6 Hz, 2H), 7.78 (d, J = 8.3 Hz, 2H), 7.64 (d, J = 9.0 Hz, 4H), 7.31 (dt, J = 12.8, 7.4 Hz, 4H), 7.05 (d, J = 8.8 Hz, 3H), 6.95 (t, J = 7.6 Hz, 2H), 6.80 (d, J = 7.9 Hz, 2H), 6.71 (d, J = 7.5 Hz, 2H), 5.22 (s, 2H), 3.87 (s, 3H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.2, 154.0, 133.3, 133.2, 131.8, 130.5, 129.9, 129.1, 128.6, 128.4, 128.2, 128.1, 127.6, 127.3, 126.9, 125.9, 124.3, 121.6, 120.8, 114.2, 110.0, 55.5, 52.6. HRMS (ESI) of C₄₀H₂₈N₆OS, m/z: calcd for [M+H]⁺ 641.2118, found: 641.2120.

• 4-(4-(1-Benzyl-5-(2,3,6,7-tetramethoxy-9H-carbazol-9-yl)-1H-1,2,3-triazol-4-yl)phenyl)-7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazole (7b). Compound 7b was synthesized according to the general procedure C (yield 48%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 7.89 (d, J = 8.9 Hz, 2H), 7.81 (d, J = 8.6 Hz, 2H), 7.68–7.61 (m, 4H), 7.48 (s, 2H), 7.14 (d, J = 7.4 Hz, 1H), 7.05 (d, J = 8.0 Hz, 4H), 6.82 (d, J = 7.6 Hz, 2H), 6.15 (s, 2H), 5.21 (s, 2H), 4.05 (s, 6H), 3.88 (s, 3H), 3.63 (s, 6H). ¹³C NMR (101 MHz, chloroform-d) δ 160.0, 154.2, 154.0, 149.0, 145.7, 142.8, 137.7, 134.4, 133.5, 133.3, 131.8, 130.5, 129.9, 129.7, 129.0, 128.6, 128.5, 128.3, 127.9, 127.3, 125.8, 116.5, 114.2, 102.3, 93.7, 56.8, 56.3, 55.5, 52.4. HRMS (ESI) of C₄₄H₃₆N₆O₅S, m/z: calcd for [M+H]⁺ 761.2541, found: 761.2534.

• 4-(4-(5-(9H-Carbazol-9-yl)-1-(4-methoxyphenyl)-1H-1,2,3-triazol-4-yl)phenyl)-7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazole (7c). Compound 7c was synthesized according to the general procedure C (yield 31%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 8.13 (d, J = 7.3 Hz, 2H), 7.89 (d, J = 8.8 Hz, 2H), 7.81 (d, J = 8.5 Hz, 2H), 7.68–7.63 (m, 4H), 7.39–7.30 (m, 4H), 7.17 (d, J = 9.0 Hz, 2H), 7.09–7.05 (m, 4H), 6.68 (d, J = 9.0 Hz, 2H), 3.88 (s, 3H), 3.68 (s, 3H). ¹³C NMR (101 MHz, chloroform-d) δ 160.3, 160.0, 154.3, 154.0, 142.6, 140.2, 137.7, 133.3, 131.9, 130.6, 129.9, 129.6, 129.0, 128.3, 127.3, 127.1, 126.1, 124.5, 124.3, 121.7, 120.9, 114.7, 114.2, 110.2, 55.5, 55.5. HRMS (ESI) of C₄₀H₂₈N₆O₂S, m/z: calcd for [M+H]⁺ 657.2067, found: 657.2070.

• 4-(2-(1-benzyl-5-(9H-carbazol-9-yl)-1H-1,2,3-triazol-4-yl)phenyl)-7-(4-methoxyphenyl)benzo[c][1,2,5]thiadiazole (7d). Compound 7d was synthesized according to the general procedure C (yield 51%) as a yellow solid. ¹H NMR (400 MHz, chloroform-d) δ 7.85 (d, J = 7.7 Hz, 1H), 7.79 (d, J = 8.4 Hz, 2H), 7.75 (d, J = 7.8 Hz, 2H), 7.47 (m, 1H), 7.36 (m, 1H), 7.29 (d, J = 7.3 Hz, 1H), 7.23 (d, J = 7.8 Hz, 1H), 7.07 (d, J = 8.7 Hz, 5H), 6.96–6.90 (m, 3H), 6.81 (t, J = 7.5 Hz, 2H), 6.43 (d, J = 7.8 Hz, 2H), 6.22 (d, J = 7.9 Hz, 2H), 5.10 (s, 2H), 3.92 (s, 3H). ¹³C NMR (101 MHz, chloroform-d) δ 159.8, 153.9, 153.3, 138.3, 136.8, 133.3, 132.6, 131.7, 130.8, 130.7, 129.8, 129.5, 128.8, 128.6, 128.4, 128.2, 127.6, 126.5, 126.2, 123.6, 121.3, 120.0, 114.0, 109.0, 55.5, 53.0. HRMS (ESI) of C₄₀H₂₈N₆OS, m/z: calcd for [M+H]+ 641.2118, found: 641.2118.

3.4. Optical and Electrochemical Investigation

UV–Vis spectra in dichloromethane solutions were recorded on an Agilent Cary 300 spectrometer (Santa Clara, CA, USA), for the fluorescence spectra, a Cary Eclipse spectrofluorometer has been used. All measured luminescence spectra were corrected for nonuniformity of detector spectral sensitivity. Rhodamine 6G (φ_fl 0.95) in ethanol was used as a reference for the luminescence quantum yield measurements. The luminescence quantum yields were calculated using equation:

${\mathsf{\phi }}_{\mathrm{i}}={\mathsf{\phi }}_0\frac{\left(1-{10}^{-A_0}\right)\times S_{\mathrm{i}}\times n_{\mathrm{i}}^2}{\left(1-{10}^{-A_{\mathrm{i}}}\right)\times S_0\times n_0^{2^{\prime }}}$

where φ_i and φ₀ are the luminescence quantum yields of the studied solution and the standard compound, respectively; A_i and A₀ are the absorptions of the studied solution and the standard, respectively; S_i and S₀ are the areas underneath the curves of the luminescence spectra of the studied solution and the standard, respectively; and n_i and n₀ are the refractive indices of the solvents for the substance under study and the standard compound (n_i 1.4242, DCM; n₀ 1.361, EtOH).

3.5. Voltammetry Studies

Electrochemical measurements were carried out at 22 °C with a Metrohm Autolab B.V. potentiostat type: PGSTAT128N. Cyclic voltammetry (CV) experiments were performed in three-electrode cell equipped with a glassy carbon (GC) working electrode (disk d 2 mm), Ag/AgCl reference electrode, and platinum counter electrode. Compounds were dissolved in degassed dry DCM containing TBAHFP as the supporting electrolyte (0.1 M). Dry argon gas was bubbled through the solutions for 10 min before cyclic voltammetry experiments. The applied scan rate for CV was 200 mV s⁻¹. In ESI cyclic voltammograms are given relative to the Ag/AgCl reference electrode. Energies of the frontier molecular orbitals (FMOs) were calculated against ferrocene/ferrocenium (Fc/Fc+) as internal standard as follows: HOMO, eV = –Eox, V–4.8; LUMO, eV = –Ered, V–4.8, since the energy level of ferrocene/ferrocenium is 4.8 eV below the vacuum level [64].

3.6. OLED Fabrication and Characterization

OLED devices were fabricated on ITO-coated glass substrates that were pre-cleaned according to the standard procedure as described in [65]. The hole transport, light-emitting, electron transport layers and LiF(1 nm)/Al(80) as cathode were deposited sequentially using thermal vacuum evaporation (TVE) at a residual pressure of 4 × 10⁻⁶ mbar. The electroluminescence spectra of OLEDs were recorded using an Avantes 2048 fiber-optic spectrofluorimeter (Apeldoorn, The Netherlands). Voltage–current and voltage–brightness characteristics were recorded with a Keithley 2601 SourceMeter (Tektronix, Beaverton, OR, USA), a Keithley 485 picoampermeter, and a TKA-04/3 luxmeter-brightness meter (TKA Scientific Instruments, Saint Petersburg, Russia). Preparations of the OLED samples and the measurements of their spectral and optoelectronic characteristics were performed at room temperature in the argon atmosphere glovebox with maximum oxygen and moisture presence of 10 ppm.

4. Conclusions

In summary, we developed an efficient synthetic pathway to new series of 5-(aryl)amino-1,2,3-triazole-containing 2,1,3-benzothiadiazole derivatives. The method is based on 1,3-dipolar azide–nitrile cycloaddition followed by Buchwald–Hartwig cross-coupling to afford the corresponding N-aryl and N,N-diaryl substituted 5-amino-1,2,3-triazolyl 2,1,3-benzothiadiazoles under catalysis with (THP-Dipp)Pd(cinn)Cl complex thus opening the straightforward access to unknown before triazole-linked D-A systems. In addition, the one-pot diarylative Pd-catalyzed heterocyclization has been also performed to demonstrate a quick installation of carbazole donors into BTD structure. The quantum yields of photoluminescence of the obtained derivatives are rather high (54–95%) and depend to a large extent on the strength of the donor component, which was changed in the series from Ph- to diphenylamino- and carbazole moieties. The maximum quantum yield among the obtained compounds is close to 100%. Based on the most photoactive derivative and wide bandgap host material mCP, a light-emitting layer of OLED was made. The device showed a maximum brightness of 8000 cd/m² at an applied voltage of 18 V. The maximum current efficiency of the device reaches a value of 3.29 cd/A.

Author Contributions

Conceptualization: P.S.G. and S.N.O.; methodology: P.S.G.; investigation: P.S.G. (synthesis, NMR spectra registering and characterization), A.N.P. (synthesis), A.F.A. and M.A.T. (synthesis of (THP-Dipp)Pd(cinn)Cl), S.D.T. (voltammetry studies), D.A.L. and A.V.D. (OLED fabrication), A.F.S. (X-ray investigation), A.N.R. (HRMS spectra registering and characterization); writing—original draft preparation: P.S.G. and S.N.O.; writing—review and editing: P.S.G. and S.N.O.; supervision: P.S.G.; project administration: P.S.G.; funding acquisition: P.S.G. All authors have read and agreed to the published version of the manuscript.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Data are contained within the article and Supplementary Materials.

Acknowledgments

Spectral characterization, NMR and X-ray diffraction studies were performed using the equipment of Center for molecular composition studies of INEOS RAS with the support from Ministry of Science and Higher Education of the Russian Federation.

Conflicts of Interest

The authors declare no conflicts of interest.

Footnotes

Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Figures, Schemes and Tables

Scheme 1. Synthetic approaches to: (a) 5-amino-1,2,3-triazoles and 5-arylamino-1,2,3-triazoles; (b) BTD-containing N-aryl- and N,N-diarylsubstituted 5-amino-1,2,3-triazoles.

Scheme 2. Synthesis of acetonitrile containing BTDs 3a and 3b. * Reaction conditions: 1 or 2 (1 equiv.), nitrile (1.2 equiv.), NaHCO3 (3 equiv.), Pd(PPh3)2Cl2 (5 mol.%), dioxane/H2O, 100 °C, 6 h.

Scheme 3. Synthesis of BTD-containing 5-amino-1,2,3-triazoles 4a–g. Reaction conditions: 3a or 3b (3 mmol), aryl (alkyl) azide (3 equiv.), KOtBu (0.5 equiv.), DMSO (8 mL), 70 °C, 3 h.

Scheme 4. Buchwald–Hartwig cross-coupling synthesis of N-monosubstituted arylamino-1,2,3-triazole-2,1,3-benzothiadiazoles 5a–f. Reaction conditions: 4 (0.2 mmol), (het)aryl-Br (5 equiv.), (THP-Dipp)Pd(cinn)Cl (5 mol.%), NaOtBu (3 equiv.), 1,4-dioxane (1.0 mL), 110 °C, 24 h.

Scheme 5. The Buchwald–Hartwig cross-coupling synthesis of N,N-disubstituted-arylamino-1,2,3-triazole-2,1,3-benzothiadiazoles 6a–l. Reaction conditions: 5-amino-1,2,3-triazole-2,1,3-benzothiadiazole 4 (0.2 mmol), aryl-Br (5 equiv.), (THP-Dipp)Pd(cinn)Cl (5 mol.%), t-Bu3P-HBF4 (10 mol.%), NaOtBu (3 equiv.), 1,4-dioxane (1.0 mL), 110 °C, 24 h.

Scheme 6. One-pot diarylative cyclization synthesis of 7a–d. Reaction conditions: 5-amino-1,2,3-triazole-2,1,3-benzothiadiazole 4 (0.2 mmol), 2,2′-dibromobiphenyl (1.0 equiv.), (THP-Dipp)Pd(cinn)Cl (5 mol.%), t-Bu3P-HBF4 (10 mol.%), NaOtBu (3 equiv.), 1,4-dioxane (1.0 mL), 110 °C, 24 h.

Figure 1. Structure of 6a (CCDC 2345715), 6g (CCDC 2345713), and 7a (CCDC 2345714).

Figure 2. Electronic absorption and emission spectra of 4b, 5f, 6d, 6g, and 7a in dichloromethane, C = 2 × 10−5 M.

Figure 3. Energy band diagram of the OLED structure with the co-deposited EML layer 6d/mCP.

Figure 4. (a) Normalized EL spectrum; (b) the CIE chromaticity diagram of OLED based on co-deposited EML layer 6d/mCP.

Figure 5. Current density–voltage dependence and voltage–brightness characteristics of the OLED based on EML layer 6d/mCP.

Table 1

The long-wavelength absorption and emission bands, quantum yields, the frontier molecular orbitals (FMOs) energies ^a for compounds 4b, 5f, 6d, 6g, and 7a in DCM.

Compound	λabs, nm	λem, nm	QY, Air, %	HOMO, eV	LUMO, eV	Gap, eV
4b	407	562	89	−5.54	−3.49	2.05
5f	405	550	86	−5.59	−3.48	2.11
6d	405	546	95	−5.78	−3.48	2.30
6g	391	529	54	−5.78	−3.47	2.31
7a	404	540	95	−5.83	−3.49	2.34

^a Calculated from electrochemical data.

Table 2

EL characteristics of the studied OLED with a dye 6d content in of 15 wt.%.

Light-Emitting Layer	Uon, V	Max. Brightness, cd/m2	Max. Efficiency		CIE		λmax EL, nm
			CE, cd/A	PE, lm/W	x	y
6d/mCP	4.0	8000	3.29	1.78	0.319	0.561	555

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/molecules29092151/s1, The following are available online: copies of ¹H and ¹³C NMR spectra for all novel compounds, voltammograms for 4b, 5f, 6d, 6g, 7a. Deposition Numbers 2345715 (for 6a), 2345713 (for 6g), and 2345714 (for 7a) contain the supplementary crystallographic data for this paper. These data are provided free of charge by the joint Cambridge Crystallographic Data Centre service www.ccdc.cam.ac.uk/structures (accessed on 2 May 2024).

References

1. Anthony, J.E. The larger acenes: Versatile organic semiconductors. Angew. Chem. Int. Ed.; 2008; 47, pp. 452-483. [DOI: https://dx.doi.org/10.1002/anie.200604045] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/18046697]

2. Watson, M.D.; Fechtenkotter, A.; Mullen, K. Big is beautiful—“aromaticity” revisited from the viewpoint of macromolecular and supramolecular benzene chemistry. Chem. Rev.; 2001; 101, pp. 1267-1300. [DOI: https://dx.doi.org/10.1021/cr990322p]

3. Mitschke, U.; Bäuerle, P. The electroluminescence of organic materials. J. Mater. Chem.; 2000; 10, pp. 1471-1507. [DOI: https://dx.doi.org/10.1039/a908713c]

4. Sukhikh, T.S.; Ogienko, D.S.; Bashirov, D.A.; Konchenko, S.N. Luminescent complexes of 2,1,3-benzothiadiazole derivatives. Russ. Chem. Bull.; 2019; 68, pp. 651-661. [DOI: https://dx.doi.org/10.1007/s11172-019-2472-9]

5. Muller, C.D.; Falcou, A.; Reckefuss, N.; Rojahn, M.; Wiederhirn, V.; Rudati, P.; Frohne, H.; Nuyken, O.; Becker, H.; Meerholz, K. Multi-colour organic light-emitting displays by solution processing. Nature; 2003; 421, pp. 829-833. [DOI: https://dx.doi.org/10.1038/nature01390]

6. Kato, S.; Matsumoto, T.; Shigeiwa, M.; Gorohmaru, H.; Maeda, S.; Ishi-i, T.; Mataka, S. Novel 2,1,3-benzothiadiazole-based red-fluorescent dyes with enhanced two-photon absorption cross-sections. Chem. Eur. J.; 2006; 12, pp. 2303-2317. [DOI: https://dx.doi.org/10.1002/chem.200500921]

7. Tsao, H.N.; Cho, D.M.; Park, I.; Hansen, M.R.; Mavrinskiy, A.; Yoon, D.Y.; Graf, R.; Pisula, W.; Spiess, H.W.; Mullen, K. Ultrahigh mobility in polymer field-effect transistors by design. J. Am. Chem. Soc.; 2011; 133, pp. 2605-2612. [DOI: https://dx.doi.org/10.1021/ja108861q]

8. Zhang, M.; Tsao, H.N.; Pisula, W.; Yang, C.; Mishra, A.K.; Mullen, K. Field-effect transistors based on a benzothiadiazole-cyclopentadithiophene copolymer. J. Am. Chem. Soc.; 2007; 129, pp. 3472-3473. [DOI: https://dx.doi.org/10.1021/ja0683537] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/17341077]

9. Sonar, P.; Singh, S.P.; Li, Y.; Soh, M.S.; Dodabalapur, A. A low-bandgap diketopyrrolopyrrole-benzothiadiazole-based copolymer for high-mobility ambipolar organic thin-film transistors. Adv. Mater.; 2010; 22, pp. 5409-5413. [DOI: https://dx.doi.org/10.1002/adma.201002973]

10. Velusamy, M.; Justin Thomas, K.R.; Lin, J.T.; Hsu, Y.C.; Ho, K.C. Organic dyes incorporating low-band-gap chromophores for dye-sensitized solar cells. Org. Lett.; 2005; 7, pp. 1899-1902. [DOI: https://dx.doi.org/10.1021/ol050417f]

11. Zhu, W.; Wu, Y.; Wang, S.; Li, W.; Li, X.; Chen, J.; Wang, Z.s.; Tian, H. Organic D-A-π-A Solar Cell Sensitizers with Improved Stability and Spectral Response. Adv. Funct. Mater.; 2010; 21, pp. 756-763. [DOI: https://dx.doi.org/10.1002/adfm.201001801]

12. Li, Y. Molecular design of photovoltaic materials for polymer solar cells: Toward suitable electronic energy levels and broad absorption. Acc. Chem. Res.; 2012; 45, pp. 723-733. [DOI: https://dx.doi.org/10.1021/ar2002446] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/22288572]

13. Du, J.; Biewer, M.C.; Stefan, M.C. Benzothiadiazole building units in solution-processable small molecules for organic photovoltaics. J. Mater. Chem. A; 2016; 4, pp. 15771-15787. [DOI: https://dx.doi.org/10.1039/C6TA06241E]

14. Liu, Q.; Zhan, H.; Ho, C.L.; Dai, F.R.; Fu, Y.; Xie, Z.; Wang, L.; Li, J.H.; Yan, F.; Huang, S.P. et al. Oligothiophene-bridged bis(arylene ethynylene) small molecules for solution-processible organic solar cells with high open-circuit voltage. Chem. Asian J.; 2013; 8, pp. 1892-1900. [DOI: https://dx.doi.org/10.1002/asia.201300244] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/23650016]

15. Patrizi, B.; Iagatti, A.; Abbondanza, L.; Bussotti, L.; Zanardi, S.; Salvalaggio, M.; Fusco, R.; Foggi, P. Ultrafast Intramolecular and Solvation Dynamics in 4,7-Bis (4,5-dibutylbenzo[1,2-b:4,3-b′]bisthiophene[1,2-b:4,3-b′]bisthiophen-2-yl)-2,1,3-benzothiadiazole. J. Phys. Chem. C; 2019; 123, pp. 5840-5852. [DOI: https://dx.doi.org/10.1021/acs.jpcc.8b11191]

16. Neto, B.A.; Carvalho, P.H.; Correa, J.R. Benzothiadiazole Derivatives as Fluorescence Imaging Probes: Beyond Classical Scaffolds. Acc. Chem. Res.; 2015; 48, pp. 1560-1569. [DOI: https://dx.doi.org/10.1021/ar500468p] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/25978615]

17. Guo, J.; Wang, S.; Dai, N.; Teo, Y.N.; Kool, E.T. Multispectral labeling of antibodies with polyfluorophores on a DNA backbone and application in cellular imaging. Proc. Natl. Acad. Sci. USA; 2011; 108, pp. 3493-3498. [DOI: https://dx.doi.org/10.1073/pnas.1017349108]

18. Li, C.; Tang, J.; Xie, J. Synthesis of crosslinking amino acids by click chemistry. Tetrahedron; 2009; 65, pp. 7935-7941. [DOI: https://dx.doi.org/10.1016/j.tet.2009.07.054]

19. Moro, A.V.; Ferreira, P.C.; Migowski, P.; Rodembusch, F.S.; Dupont, J.; Lüdtke, D.S. Synthesis and photophysical properties of fluorescent 2,1,3-benzothiadiazole-triazole-linked glycoconjugates: Selective chemosensors for Ni(II). Tetrahedron; 2013; 69, pp. 201-206. [DOI: https://dx.doi.org/10.1016/j.tet.2012.10.043]

20. Kim, O.-K.; Lee, K.-S.; Woo, H.Y.; Kim, K.-S.; He, G.S.; Swiatkiewicz, J.; Prasad, P.N. New Class of Two-Photon-Absorbing Chromophores Based on Dithienothiophene. Chem. Mater.; 2000; 12, pp. 284-286. [DOI: https://dx.doi.org/10.1021/cm990662r]

21. Li, C.; Henry, E.; Mani, N.K.; Tang, J.; Brochon, J.C.; Deprez, E.; Xie, J. Click Chemistry to Fluorescent Amino Esters: Synthesis and Spectroscopic Studies. Eur. J. Org. Chem.; 2010; 2010, pp. 2395-2405. [DOI: https://dx.doi.org/10.1002/ejoc.201000042]

22. Dyrager, C.; Vieira, R.P.; Nyström, S.; Nilsson, K.P.R.; Storr, T. Synthesis and evaluation of benzothiazole-triazole and benzothiadiazole-triazole scaffolds as potential molecular probes for amyloid-β aggregation. New J. Chem.; 2017; 41, pp. 1566-1573. [DOI: https://dx.doi.org/10.1039/C6NJ01703G]

23. da Cruz, E.H.G.; Carvalho, P.H.P.R.; Corrêa, J.R.; Silva, D.A.C.; Diogo, E.B.T.; de Souza Filho, J.D.; Cavalcanti, B.C.; Pessoa, C.; de Oliveira, H.C.B.; Guido, B.C. et al. Design, synthesis and application of fluorescent 2,1,3-benzothiadiazole-triazole-linked biologically active lapachone derivatives. New J. Chem.; 2014; 38, 2569. [DOI: https://dx.doi.org/10.1039/c3nj01499a]

24. Chen, S.; Liu, Y.; He, M.; Huang, J. Synthesis of a Benzothiadiazole-Based D−A Molecule with Aggregation-Induced Emission and Controlled Assembly Properties. Processes; 2021; 9, 1094. [DOI: https://dx.doi.org/10.3390/pr9071094]

25. Brombosz, S.M.; Appleton, A.L.; Zappas, A.J., 2nd; Bunz, U.H. Water-soluble benzo- and naphtho-thiadiazole-based bistriazoles and their metal-binding properties. Chem. Commun.; 2010; 46, pp. 1419-1421. [DOI: https://dx.doi.org/10.1039/b920484a] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/20162134]

26. Lieber, E.; Chao, T.S.; Rao, C.N.R. Synthesis and Isomerization of Substituted 5-Amino-1,2,3-triazoles1. J. Org. Chem.; 1957; 22, pp. 654-662. [DOI: https://dx.doi.org/10.1021/jo01357a018]

27. Cottrell, I.F.; Hands, D.; Houghton, P.G.; Humphrey, G.R.; Wright, S.H.B. An improved procedure for the preparation of 1-benzyl-1H-1,2,3-triazoles from benzyl azides. J. Heterocycl. Chem.; 2009; 28, pp. 301-304. [DOI: https://dx.doi.org/10.1002/jhet.5570280216]

28. Pokhodylo, N.T.; Matiychuk, V.S.; Obushak, N.B. Synthesis of 1H-1,2,3-triazole derivatives by the cyclization of aryl azides with 2-benzothiazolylacetonone, 1,3-benzo-thiazol-2-ylacetonitrile, and (4-aryl-1,3-thiazol-2-yl)acetonitriles. Chem. Heterocycl. Compd.; 2009; 45, pp. 483-488. [DOI: https://dx.doi.org/10.1007/s10593-009-0287-6]

29. Krishna, P.M.; Ramachary, D.B.; Peesapati, S. Azide–acetonitrile “click” reaction triggered by Cs₂CO₃: The atom-economic, high-yielding synthesis of 5-amino-1,2,3-triazoles. RSC Adv.; 2015; 5, pp. 62062-62066. [DOI: https://dx.doi.org/10.1039/C5RA12308A]

30. Fang, X.; Zhang, T.; Fang, W.; Zhang, G.; Li, Y.; Li, Y. Synthesis of Functionalized Triazoles on DNA via Azide-Acetonitrile “Click” Reaction. Org. Lett.; 2023; 25, pp. 8326-8331. [DOI: https://dx.doi.org/10.1021/acs.orglett.3c03404]

31. Gribanov, P.S.; Atoian, E.M.; Philippova, A.N.; Topchiy, M.A.; Asachenko, A.F.; Osipov, S.N. One-Pot Synthesis of 5-Amino-1,2,3-triazole Derivatives via Dipolar Azide−Nitrile Cycloaddition and Dimroth Rearrangement under Solvent-Free Conditions. Eur. J. Org. Chem.; 2021; 2021, pp. 1378-1384. [DOI: https://dx.doi.org/10.1002/ejoc.202001620]

32. Gribanov, P.S.; Philippova, A.N.; Topchiy, M.A.; Minaeva, L.I.; Asachenko, A.F.; Osipov, S.N. General Method of Synthesis of 5-(Het)arylamino-1,2,3-triazoles via Buchwald-Hartwig Reaction of 5-Amino- or 5-Halo-1,2,3-triazoles. Molecules; 2022; 27, 1999. [DOI: https://dx.doi.org/10.3390/molecules27061999] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/35335361]

33. Gribanov, P.S.; Lypenko, D.A.; Dmitriev, A.V.; Pozin, S.I.; Topchiy, M.A.; Asachenko, A.F.; Loginov, D.A.; Osipov, S.N. Synthesis and optical properties of novel unsymmetrically substituted benzothiadiazole-based luminophores. Mendeleev Commun.; 2021; 31, pp. 33-35. [DOI: https://dx.doi.org/10.1016/j.mencom.2021.01.009]

34. Peng, Z.; Wang, Z.; Huang, Z.; Liu, S.; Lu, P.; Wang, Y. Expression of anti-Kasha’s emission from amino benzothiadiazole and its utilization for fluorescent chemosensors and organic light emitting materials. J. Mater. Chem. C; 2018; 6, pp. 7864-7873. [DOI: https://dx.doi.org/10.1039/C8TC02416B]

35. Heravi, M.M.; Kheilkordi, Z.; Zadsirjan, V.; Heydari, M.; Malmir, M. Buchwald-Hartwig reaction: An overview. J. Organomet. Chem.; 2018; 861, pp. 17-104. [DOI: https://dx.doi.org/10.1016/j.jorganchem.2018.02.023]

36. Liu, Y.-F.; Wang, C.-L.; Bai, Y.-J.; Han, N.; Jiao, J.-P.; Qi, X.-L. A Facile Total Synthesis of Imatinib Base and Its Analogues. Org. Process Res. Dev.; 2008; 12, pp. 490-495. [DOI: https://dx.doi.org/10.1021/op700270n]

37. Beletskaya, I.P.; Averin, A.D. Metal-catalyzed reactions for the C(sp2)–N bond formation: Achievements of recent years. Russ. Chem. Rev.; 2021; 90, pp. 1359-1396. [DOI: https://dx.doi.org/10.1070/RCR4999]

38. Dorel, R.; Grugel, C.P.; Haydl, A.M. The Buchwald-Hartwig Amination After 25 Years. Angew. Chem. Int. Ed.; 2019; 58, pp. 17118-17129. [DOI: https://dx.doi.org/10.1002/anie.201904795] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/31166642]

39. Forero-Cortés, P.A.; Haydl, A.M. The 25th Anniversary of the Buchwald–Hartwig Amination: Development, Applications, and Outlook. Org. Process Res. Dev.; 2019; 23, pp. 1478-1483. [DOI: https://dx.doi.org/10.1021/acs.oprd.9b00161]

40. Ouyang, J.-S.; Liu, S.; Pan, B.; Zhang, Y.; Liang, H.; Chen, B.; He, X.; Chan, W.T.K.; Chan, A.S.C.; Sun, T.-Y. et al. A Bulky and Electron-Rich N-Heterocyclic Carbene–Palladium Complex (SIPr)Ph2Pd(cin)Cl: Highly Efficient and Versatile for the Buchwald–Hartwig Amination of (Hetero)aryl Chlorides with (Hetero)aryl Amines at Room Temperature. ACS Catal.; 2021; 11, pp. 9252-9261. [DOI: https://dx.doi.org/10.1021/acscatal.1c01929]

41. Astakhov, A.V.; Chernenko, A.Y.; Kutyrev, V.V.; Ranny, G.S.; Minyaev, M.E.; Chernyshev, V.M.; Ananikov, V.P. Selective Buchwald–Hartwig arylation ofC-amino-1,2,4-triazoles and other coordinating aminoheterocycles enabled by bulky NHC ligands and TPEDO activator. Inorg. Chem. Front.; 2023; 10, pp. 218-239. [DOI: https://dx.doi.org/10.1039/D2QI01832B]

42. Moss, T.; Addie, M.; Nowak, T.; Waring, M. Room-Temperature Palladium-Catalyzed Coupling of Heteroaryl Amines with Aryl or Heteroaryl Bromides. Synlett; 2012; 2012, pp. 285-289. [DOI: https://dx.doi.org/10.1055/s-0031-1290069]

43. Ouyang, J.S.; Zhang, X.; Pan, B.; Zou, H.; Chan, A.S.C.; Qiu, L. Solvent-Free Buchwald-Hartwig Amination of Heteroaryl Chlorides by N-Heterocyclic Carbene-Palladium Complex (SIPr)(Ph2)Pd(cin)Cl at Room Temperature. Org. Lett.; 2023; 25, pp. 7491-7496. [DOI: https://dx.doi.org/10.1021/acs.orglett.3c02651]

44. Semeniuchenko, V.; Sharif, S.; Day, J.; Chandrasoma, N.; Pietro, W.J.; Manthorpe, J.; Braje, W.M.; Organ, M.G. (DiMeIHept(Cl))Pd: A Low-Load Catalyst for Solvent-Free (Melt) Amination. J. Org. Chem.; 2021; 86, pp. 10343-10359. [DOI: https://dx.doi.org/10.1021/acs.joc.1c01057]

45. Olsen, E.P.K.; Arrechea, P.L.; Buchwald, S.L. Mechanistic Insight Leads to a Ligand Which Facilitates the Palladium-Catalyzed Formation of 2-(Hetero)Arylaminooxazoles and 4-(Hetero)Arylaminothiazoles. Angew. Chem. Int. Ed.; 2017; 56, pp. 10569-10572. [DOI: https://dx.doi.org/10.1002/anie.201705525]

46. Khadra, A.; Mayer, S.; Organ, M.G. Pd-PEPPSI-IPent(Cl): A Useful Catalyst for the Coupling of 2-Aminopyridine Derivatives. Chem. Eur. J.; 2017; 23, pp. 3206-3212. [DOI: https://dx.doi.org/10.1002/chem.201605490] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/28066950]

47. Reddy, M.V.K.; Anusha, G.; Reddy, P.V.G. Sterically enriched bulky 1,3-bis(N,N′-aralkyl)benzimidazolium based Pd-PEPPSI complexes for Buchwald–Hartwig amination reactions. New J. Chem.; 2020; 44, pp. 11694-11703. [DOI: https://dx.doi.org/10.1039/D0NJ01294G]

48. Topchiy, M.A.; Asachenko, A.F.; Nechaev, M.S. Solvent-Free Buchwald–Hartwig Reaction of Aryl and Heteroaryl Halides with Secondary Amines. Eur. J. Org. Chem.; 2014; 2014, pp. 3319-3322. [DOI: https://dx.doi.org/10.1002/ejoc.201402077]

49. Topchiy, M.A.; Dzhevakov, P.B.; Rubina, M.S.; Morozov, O.S.; Asachenko, A.F.; Nechaev, M.S. Solvent-Free Buchwald–Hartwig (Hetero)arylation of Anilines, Diarylamines, and Dialkylamines Mediated by Expanded-Ring N-Heterocyclic Carbene Palladium Complexes. Eur. J. Org. Chem.; 2016; 2016, pp. 1908-1914. [DOI: https://dx.doi.org/10.1002/ejoc.201501616]

50. Flahaut, A.; Roland, S.; Mangeney, P. Allylic alkylation and amination using mixed (NHC)(phosphine) palladium complexes under biphasic conditions. J. Organomet. Chem.; 2007; 692, pp. 5754-5762. [DOI: https://dx.doi.org/10.1016/j.jorganchem.2007.10.012]

51. Kim, M.; Shin, T.; Lee, A.; Kim, H. Synergistic Ligand Effect between N-Heterocyclic Carbene (NHC) and Bicyclic Phosphoramidite (Briphos) Ligands in Pd-Catalyzed Amination. Organometallics; 2018; 37, pp. 3253-3258. [DOI: https://dx.doi.org/10.1021/acs.organomet.8b00413]

52. Chen, M.-T.; Vicic, D.A.; Turner, M.L.; Navarro, O. (N-Heterocyclic Carbene)PdCl2(TEA) Complexes: Studies on the Effect of the “Throw-Away” Ligand in Catalytic Activity. Organometallics; 2011; 30, pp. 5052-5056. [DOI: https://dx.doi.org/10.1021/om200699p]

53. Yang, J.; Li, P.; Zhang, Y.; Wang, L. A new library of arsine, stibine-stabilized N-heterocyclic carbene palladium complexes: Synthesis, structures and activities in C-C and C-N coupling reactions. Dalton. Trans.; 2014; 43, pp. 14114-14122. [DOI: https://dx.doi.org/10.1039/C4DT01773K] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/25133960]

54. Ageshina, A.A.; Sterligov, G.K.; Rzhevskiy, S.A.; Topchiy, M.A.; Chesnokov, G.A.; Gribanov, P.S.; Melnikova, E.K.; Nechaev, M.S.; Asachenko, A.F.; Bermeshev, M.V. Mixed er-NHC/phosphine Pd(ii) complexes and their catalytic activity in the Buchwald-Hartwig reaction under solvent-free conditions. Dalton Trans.; 2019; 48, pp. 3447-3452. [DOI: https://dx.doi.org/10.1039/C9DT00216B] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/30793148]

55. Shirota, Y.; Kageyama, H. Charge carrier transporting molecular materials and their applications in devices. Chem. Rev.; 2007; 107, pp. 953-1010. [DOI: https://dx.doi.org/10.1021/cr050143+] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/17428022]

56. Sallenave, X.; Bucinskas, A.; Salman, S.; Volyniuk, D.; Bezvikonnyi, O.; Mimaite, V.; Grazulevicius, J.V.; Sini, G. Sensitivity of Redox and Optical Properties of Electroactive Carbazole Derivatives to the Molecular Architecture and Methoxy Substitutions. J. Phys. Chem. C; 2018; 122, pp. 10138-10152. [DOI: https://dx.doi.org/10.1021/acs.jpcc.8b02148]

57. Riedmuller, S.; Nachtsheim, B.J. Palladium-catalyzed synthesis of N-arylated carbazoles using anilines and cyclic diaryliodonium salts. Beilstein J. Org. Chem.; 2013; 9, pp. 1202-1209. [DOI: https://dx.doi.org/10.3762/bjoc.9.136] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/23843915]

58. Kerner, L.; Gmucová, K.; Kožíšek, J.; Petříček, V.; Putala, M. Easily oxidizable triarylamine materials with naphthalene and binaphthalene core: Structure–properties relationship. Tetrahedron; 2016; 72, pp. 7081-7092. [DOI: https://dx.doi.org/10.1016/j.tet.2016.09.063]

59. Seino, Y.; Inomata, S.; Sasabe, H.; Pu, Y.J.; Kido, J. High-Performance Green OLEDs Using Thermally Activated Delayed Fluorescence with a Power Efficiency of over 100 lm W(-1). Adv. Mater.; 2016; 28, pp. 2638-2643. [DOI: https://dx.doi.org/10.1002/adma.201503782]

60. Kolychev, E.L.; Asachenko, A.F.; Dzhevakov, P.B.; Bush, A.A.; Shuntikov, V.V.; Khrustalev, V.N.; Nechaev, M.S. Expanded ring diaminocarbene palladium complexes: Synthesis, structure, and Suzuki–Miyaura cross-coupling of heteroaryl chlorides in water. Dalton Trans.; 2013; 42, 6859. [DOI: https://dx.doi.org/10.1039/c3dt32860k]

61. Vallee, M.R.; Artner, L.M.; Dernedde, J.; Hackenberger, C.P. Alkyne phosphonites for sequential azide-azide couplings. Angew. Chem. Int. Ed.; 2013; 52, pp. 9504-9508. [DOI: https://dx.doi.org/10.1002/anie.201302462] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/23861231]

62. Alvarez, S.G.; Alvarez, M.T. A Practical Procedure for the Synthesis of Alkyl Azides at Ambient Temperature in Dimethyl Sulfoxide in High Purity and Yield. Synthesis; 1997; 1997, pp. 413-414. [DOI: https://dx.doi.org/10.1055/s-1997-1206]

63. Okuda, Y.; Imafuku, K.; Tsuchida, Y.; Seo, T.; Akashi, H.; Orita, A. Process-Controlled Regiodivergent Copper-Catalyzed Azide-Alkyne Cycloadditions: Tailor-made Syntheses of 4- and 5-Bromotriazoles from Bromo(phosphoryl)ethyne. Org. Lett.; 2020; 22, pp. 5099-5103. [DOI: https://dx.doi.org/10.1021/acs.orglett.0c01681] [PubMed: https://www.ncbi.nlm.nih.gov/pubmed/32525324]

64. Pommerehne, J.; Vestweber, H.; Guss, W.; Mahrt, R.F.; Bässler, H.; Porsch, M.; Daub, J. Efficient two layer leds on a polymer blend basis. Adv. Mater.; 2004; 7, pp. 551-554. [DOI: https://dx.doi.org/10.1002/adma.19950070608]

65. Gribanov, P.S.; Loginov, D.A.; Lypenko, D.A.; Dmitriev, A.V.; Pozin, S.I.; Aleksandrov, A.E.; Tameev, A.R.; Martynov, I.L.; Chernyadyev, A.Y.; Osipov, S.N. New Unsymmetrically Substituted Benzothiadiazole-Based Luminophores: Synthesis, Optical, Electrochemical Studies, Charge Transport, and Electroluminescent Characteristics. Molecules; 2021; 26, 7596. [DOI: https://dx.doi.org/10.3390/molecules26247596]