Ionic multiresonant thermally activated delayed fluorescence emitters for light emitting electrochemical cells

• Merve Karaman,
• Abhishek Kumar Gupta,
• Subeesh Madayanad Suresh,
• Tomas Matulaitis,
• Lorenzo Mardegan,
• Daniel Tordera,
• Henk J. Bolink,
• Sen Wu,
• Stuart Warriner,
• Ifor D. Samuel and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2022, 18, 1311–1321, doi:10.3762/bjoc.18.136

• -butylammonium hexafluorophosphate as the supporting electrolyte (Figure 3a and Table S2 in Supporting Information File 1). The oxidation and reduction of both emitters showed good reversibility, which is beneficial for better performance in LEEC devices [31]. The oxidation potentials, Eox, determined from the

• . DiKTa possesses an oxidation potential of 1.66 V and an associated HOMO energy level of −5.93 eV. The reduction potentials, Ered, are −1.67 V and −1.61 V, respectively, for DiKTa-OBuIm and DiKTa-DPA-OBuIm. The corresponding LUMO levels are −3.13 eV and −3.18 eV for DiKTa-OBuIm and DiKTa-DPA-OBuIm

• , respectively. The LUMO values of both emitters match that of DiKTa (−3.11 eV), which suggests that reduction occurs on the DiKTa core in both compounds, a contention corroborated by the DFT calculations. The electrochemical gap reduced from 2.72 V in DiKTa-OBuIm to 2.06 V in DiKTa-DPA-OBuIm, a trend that is in

Make or break: the thermodynamic equilibrium of polyphosphate kinase-catalysed reactions

• Michael Keppler,
• Sandra Moser,
• Henning J. Jessen,
• Christoph Held and
• Jennifer N. Andexer

Beilstein J. Org. Chem. 2022, 18, 1278–1288, doi:10.3762/bjoc.18.134

• '-deoxyadenosine 5'-triphosphate) could be discussed as an example for this (Table 1). Here, PPK2 enzymes are used to produce 2-Cl-ATP which is then reduced to the desired product. The final reduction could be considered as a pull effect on the PPK2 reaction, since it removes 2-Cl-ATP from the PPK2 reaction

• equilibrium. In fact, the authors observed an (compared to the adenosine-to-ATP cascades) increased yield of 80% cladribine triphosphate, with 2-Cl-dADP being the major byproduct [22]. The incomplete conversion (despite the irreversible reduction step) has been explained by the previously mentioned myokinase

Enantioselective total synthesis of putative dihydrorosefuran, a monoterpene with an unique 2,5-dihydrofuran structure

• Irene Torres-García,
• Josefa L. López-Martínez,
• Rocío López-Domene,
• Manuel Muñoz-Dorado,
• Ignacio Rodríguez-García and
• Miriam Álvarez-Corral

Beilstein J. Org. Chem. 2022, 18, 1264–1269, doi:10.3762/bjoc.18.132

• -bromobut-2-yne in the presence of CpTiIIICl2 (generated in situ by reduction of CpTiCl3 with Mn) afforded α-hydroxyallene 3. We have recently described that this Barbier-type reaction affords α-hydroxyallenes as major products, mixed with smaller amounts of homopropargylic alcohols, either if the reaction

Vicinal ketoesters – key intermediates in the total synthesis of natural products

• Marc Paul Beller and
• Ulrich Koert

Beilstein J. Org. Chem. 2022, 18, 1236–1248, doi:10.3762/bjoc.18.129

• , Scheme 6) [15]. Through a series of finely tuned CH oxidations, cedrol (31) was converted to the lactone 32. In a single step, using Riley oxidation conditions, the methyl ketone moiety was transferred to the α-ketoester 33. Reduction, lactonization, and elimination gave the ketoesters-derived enol 34

• . Oxidation of the latter compound to the α-keto-β-hydroxy ester IV using DMDO and subsequent heating in PhCF3 triggered an α-ketol rearrangement which led to ketol V. Diastereoselective reduction gave α,β-dihydroxyester 35 which was converted to (−)-jiadifenoxolane A (36) in five further steps. Palau’amine

• subsequent reduction of compound 109 gave preussochromone E (110). Conclusion The variety of examples prove that vicinal ketoesters are valuable synthetic intermediates for the synthesis of complex target structures such as natural products. α-Ketoesters, mesoxalic esters, and α,β-diketoesters can be used

Polymer and small molecule mechanochemistry: closer than ever

• José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1225–1235, doi:10.3762/bjoc.18.128

• mechanoredox reduction of inactive Cu(II) salts to catalytically active Cu(I) species (Figure 5a) [54]. Complementarily, ball milling of BaTiO3 has been used for mechanoredox ATRC reactions in which highly polarized BaTiO3 particles produced by the collisions of the milling balls were proposed to reduce the Cu

Mechanochemical bottom-up synthesis of phosphorus-linked, heptazine-based carbon nitrides using sodium phosphide

• Blaine G. Fiss,
• Georgia Douglas,
• Michael Ferguson,
• Jorge Becerra,
• Jesus Valdez,
• Trong-On Do,
• Tomislav Friščić and
• Audrey Moores

Beilstein J. Org. Chem. 2022, 18, 1203–1209, doi:10.3762/bjoc.18.125

• -PCN300) show a reduction in photoluminescent recombination, as well as a nearly two-time increase in photocurrent under broad spectrum irradiation, which are appealing properties for photocatalysis. Keywords: carbon nitride; density functional theory; mechanochemistry; phosphorus; photochemistry

• nitrogen environments, centered on 399.0 eV and 400.7 eV, respectively [16][40] (Figure 2b). This suggests that while the majority of the heptazine ring remained pyridinic in nature, partial reduction of the ring structure, due to the reductive nature of Na3P and mild oxidation during ambient workup

• quenching in water and ethanol at the end of the aging step. g-h-PCN300 featured the same three major carbon 1s peaks at 284.8, 286.2 and 288.2 eV for C=N/C=C, C=O and C–OH species, respectively, as well as the charging peak seen in g-h-PCN. In g-h-PCN300, a reduction of the C=N ratio to 37%, reduction of C

Derivatives of benzo-1,4-thiazine-3-carboxylic acid and the corresponding amino acid conjugates

• Péter Kisszékelyi,
• Tibor Peňaška,
• Klára Stankovianska,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2022, 18, 1195–1202, doi:10.3762/bjoc.18.124

• either the salt 16a·HCl or the free amine 16a in good to excellent yield (Scheme 3). We also explored the asymmetric catalytic hydrogenation of adduct 14. Our first attempt at the reduction using organocatalyzed transfer hydrogenation was unsuccessful (see Supporting Information File 1). The (R)-Ru(OAc)2

Thermally activated delayed fluorescence (TADF) emitters: sensing and boosting spin-flipping by aggregation

• Ashish Kumar Mazumdar,
• Gyana Prakash Nanda,
• Nisha Yadav,
• Upasana Deori,
• Upasha Acharyya,
• Bahadur Sk and
• Pachaiyappan Rajamalli

Beilstein J. Org. Chem. 2022, 18, 1177–1187, doi:10.3762/bjoc.18.122

• ) interactions [15]. Several molecular designs were proposed to adjust the ICT interactions through covalent D–A linking. The separation of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the donor and acceptor molecules leads to a reduction of the singlet

• the aggregated state. Consequently, a fast kRISC rate (0.74·105 s−1 for BPy-pTC and 2.06·105 s−1 for BPy-p3C) was obtained in the aggregated state (Table 2). Interestingly, a higher reduction of ΔEST as compared to BPy-pTC was obtained for the aggregates of BPy-p3C. This could have been due to the

Reductive opening of a cyclopropane ring in the Ni(II) coordination environment: a route to functionalized dehydroalanine and cysteine derivatives

• Oleg A. Levitskiy,
• Olga I. Aglamazova,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2022, 18, 1166–1176, doi:10.3762/bjoc.18.121

• , alanine, serine and cysteine derivatives are formed as an antibonding combination of the Ni dx²-y² orbital with the group orbitals of the ligands; the π* orbital of the imine and the π orbital of the phenylene fragments are also partially involved. Reduction occurs at similar potential values and is

• almost independent on the substituent at the α-carbon atom in the amino acid fragment. Electrochemical reduction of complexes containing an unsubstituted cyclopropane ring (1) or bearing Me (2) substituents is similar to that for α-alkyl derivatives: they exhibit reversible one-electron reduction (the

• Figure 1; EpA = −0.06 V (3), 0.16 V (4) vs Ag/AgCl, KCl(sat.)) can be observed for both complexes 3 and 4 (though in the latter case it is more intensive); more likely, the peak corresponds to reoxidation of the anionic species formed after the ring opening. The reduction patterns for compounds 3 and 4

Electro-conversion of cumene into acetophenone using boron-doped diamond electrodes

• Mana Kitano,
• Tsuyoshi Saitoh,
• Shigeru Nishiyama,
• Yasuaki Einaga and
• Takashi Yamamoto

Beilstein J. Org. Chem. 2022, 18, 1154–1158, doi:10.3762/bjoc.18.119

• . Therefore, we treated 1 with KO2 and 18-crown-6 to examine whether the reaction proceeds only with the superoxide. As a result, only the starting material, 1, was recovered, which indicates that 3 is produced by a concerted reaction of the direct oxidation of 1 on the anode and the reduction of dissolved

• oxygen on the cathode. Figure 2 shows a proposed mechanism. Anodic oxidation of cumene on the BDD electrode with a wide potential window preferentially affords the cumyl cation as the reaction intermediate. On the other hand, cathodic reduction of dissolved oxygen produces the superoxide and even the

Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor

• Wei-Hsin Hsu,
• Susanne Reischauer,
• Peter H. Seeberger,
• Bartholomäus Pieber and
• Dario Cambié

Beilstein J. Org. Chem. 2022, 18, 1123–1130, doi:10.3762/bjoc.18.115

• material under flow conditions. Compared to the original batch procedure, a reduction of the reaction concentration by a factor of two was necessary to ensure complete solvation of the sulfinate salt. Once homogeneous conditions were achieved, the reaction mixture was injected into the reactor, which was

• low flow rate (10 μL/min) [43][44]. An alternative approach to obtain a narrower RTD is the reduction of the reactor diameter, as this would decrease the axial dispersion [45]. Replacing the glass column (i.d. 6.6 mm) with a PTFE capillary with a smaller inner diameter (i.d. 5/32”, 3.9 mm) resulted in

Electrogenerated base-promoted cyclopropanation using alkyl 2-chloroacetates

• Kouichi Matsumoto,
• Yuta Hayashi,
• Kengo Hamasaki,
• Mizuki Matsuse,
• Hiyono Suzuki,
• Keiji Nishiwaki and
• Norihito Kawashita

Beilstein J. Org. Chem. 2022, 18, 1116–1122, doi:10.3762/bjoc.18.114

• , Kindai University 3-4-1 Kowakae, Higashi-osaka, Osaka 577-8502, Japan Department of Life Science, School of Science and Engineering, Kindai University, 3-4-1 Kowakae, Higashi-osaka, Osaka 577-8502, Japan 10.3762/bjoc.18.114 Abstract The electrochemical reduction conditions of the reaction of alkyl 2

• electrochemical production of cyclopropane derivatives is an environmentally friendly and easy to perform synthetic procedure. Keywords: alkyl 2-chloroacetates; cyclopropane derivatives; divided cell; electro-reduction; Introduction In organic chemistry, cyclopropanes and their related compounds have been

• derivatives could be formed in moderate yields through the electrochemical reduction [13][14][15][16][17][18][19][20][21] of alkyl 2-chloroacetates in a divided cell (Scheme 1, reaction 4). The in Abushanab’s study utilized metal lithium is one of the rarest and most expensive metals. In addition, the

Radical cation Diels–Alder reactions of arylidene cycloalkanes

• Kaii Nakayama,
• Hidehiro Kamiya and
• Yohei Okada

Beilstein J. Org. Chem. 2022, 18, 1100–1106, doi:10.3762/bjoc.18.112

• , single-electron oxidation of an electron-rich dienophile generates its radical cation which is then trapped by the diene (Figure 1). Since the forming cyclohexene remains in the radical cation state as well, one electron reduction is required to complete the net redox neutral transformation. Therefore, a

• electrochemistry in most cases, probably because both single-electron oxidation and reduction are made possible at the same surface [45]. This is especially true for the radical cation Diels–Alder reaction, since non-substituted β-methylstyrene, which was previously reported as an unsuccessful dienophile, was

Scope of tetrazolo[1,5-a]quinoxalines in CuAAC reactions for the synthesis of triazoloquinoxalines, imidazoloquinoxalines, and rhenium complexes thereof

• Laura Holzhauer,
• Chloé Liagre,
• Olaf Fuhr,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2022, 18, 1088–1099, doi:10.3762/bjoc.18.111

• the compatibility of the conversion with a diverse set of alkynes. Reduction of the starting material 11a to quinoxalin-2-amine as a side product was observed in some cases (see Supporting Information File 1 for details). The wide range of tolerated alkynes allows the installation of functional groups

• denitrogenative reduction to quinoxaline-2-amines 17 was noticed as a side reaction. Depending on the residue in 4-position (R, Table 1) on the pyrazine ring of the tetrazolo[1,5-a]quinoxaline, the formation of either the triazole or the imidazole product or both products occurred. For groups with electron

• especially used as CO2 reduction catalysts [38][39][40] and noninvasive imaging probes [12][41]; examples for the application in organic light-emitting diodes [35] and as photoactive CO-releasing molecule [42][43] have been reported as well. For the complexation experiments, compounds with three different

Synthesis of N-phenyl- and N-thiazolyl-1H-indazoles by copper-catalyzed intramolecular N-arylation of ortho-chlorinated arylhydrazones

• Yara Cristina Marchioro Barbosa,
• Guilherme Caneppele Paveglio,
• Claudio Martin Pereira de Pereira,
• Sidnei Moura,
• Cristiane Storck Schwalm,
• Gleison Antonio Casagrande and
• Lucas Pizzuti

Beilstein J. Org. Chem. 2022, 18, 1079–1087, doi:10.3762/bjoc.18.110

• 120 °C, which gave the product 2a in 32% yield. Increasing the time to 12 h led to a better yield of 40% (Table 1, entry 2). The best yield (60%) was reached after 24 h (Table 1, entry 3). The reduction of the temperature to 100 °C drastically decreased the yield of 2a (Table 1, entry 4). The solvent

Electrochemical hydrogenation of enones using a proton-exchange membrane reactor: selectivity and utility

• Koichi Mitsudo,
• Haruka Inoue,
• Yuta Niki,
• Eisuke Sato and
• Seiji Suga

Beilstein J. Org. Chem. 2022, 18, 1055–1061, doi:10.3762/bjoc.18.107

• proton-exchange membrane reactor is described. The reduction of enones proceeded smoothly under mild conditions to afford ketones or alcohols. The reaction occurred chemoselectively with the use of different cathode catalysts (Pd/C or Ir/C). Keywords: enone; hydrogenation; iridium; palladium; PEM

• ]. For instance, they recently reported a stereoselective reduction of alkynes to Z-alkenes using a PEM reactor. The use of a Pd/C cathode catalyst and the appropriate cathode potential realize the selective synthesis of Z-alkenes [22][23][24]. They also reported the stereoselective hydrogenation of α,β

• -unsaturated acids [25] and the reduction of benzoic acids [26]. We have been interested in electrochemical transformations for a long time [27][28][29][30][31] and are paying the most attention to the utility of PEM reactors for organic syntheses, especially chemoselective transformations. In our research, we

Synthesis, optical and electrochemical properties of (D–π)₂-type and (D–π)₂Ph-type fluorescent dyes

• Kosuke Takemura,
• Kazuki Ohira,
• Taiki Higashino,
• Keiichi Imato and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2022, 18, 1047–1054, doi:10.3762/bjoc.18.106

• reduction waves and another oxidation waves did not appear within the potential window (Figure 3a and Figure S2a, Supporting Information File 1). The corresponding cathodic peak potential (Epcox) appeared at 0.24 V for OTK-2 and 0.30 V for OTT-2, and thus the peak separations between the Epaox and Epcox

• waves are ca. 80–100 mV. This result may indicate that the two dyes undergo an electrochemically stable one-electron oxidation–reduction process, but further studies are necessary to exactly determine the number of electrons in the oxidation–reduction process. The half-wave potential (E1/2ox) was

• , indicating that the two dyes undergo an electrochemically stable oxidation–reduction process. It was found that the LUMO energy level of OTT-2 is lower than that of OTK-2, while OTT-2 and OTK-2 have comparable HOMO energy levels. Semi-empirical MO calculations showed that for OTK-2 both the HOMO and LUMO

Electrochemical Friedel–Crafts-type amidomethylation of arenes by a novel electrochemical oxidation system using a quasi-divided cell and trialkylammonium tetrafluoroborate

• Hisanori Senboku,
• Mizuki Hayama and
• Hidetoshi Matsuno

Beilstein J. Org. Chem. 2022, 18, 1040–1046, doi:10.3762/bjoc.18.105

• cathodic reduction producing hydrogen gas. We report electrochemical Friedel–Crafts-type amidomethylation of electron-rich arenes by a novel electrochemical oxidation system using a quasi-divided cell and iPr2NHEtBF4. Results and Discussion We chose 1,3,5-trimethoxybenzene (1) as a model substrate for

• , trifluoroacetic acid (TFA, 1 equiv) as a proton source for the cathodic reduction, and iPr2NEt (1 equiv) as a base for the formation of N-acyliminium ions of DMA at the anode was carried out under constant current conditions (20 mA/cm2) with 3 F/mol of electricity at 0 °C. It was found that 66% of 1 remained

• likely nucleophile in this reaction medium was the trifluoroacetate ion, which was produced by electrochemical reduction of TFA at the cathode, although we could not detect the coupling product of trifluoroacetate and the corresponding N-acyliminium ion due to the high solubility in water. In addition to

A versatile way for the synthesis of monomethylamines by reduction of N-substituted carbonylimidazoles with the NaBH₄/I₂ system

• Lin Chen,
• Xuan Zhou,
• Zhiyong Chen,
• Changxu Wang,
• Shunjie Wang and
• Hanbing Teng

Beilstein J. Org. Chem. 2022, 18, 1032–1039, doi:10.3762/bjoc.18.104

• monomethylamines by reduction of N-substituted carbonylimidazoles with NaBH4/I2 in THF at reflux temperature is described. This method used no special catalyst and various monomethylamines can be easily obtained in moderate to good yields from a wide range of raw materials including amines (primary amines and

• secondary amines), carboxylic acids and isocyanates. Besides, an interesting reduction selectivity was observed. Exploration of the reaction process shows that it undergoes a two-step pathway via a formamide intermediate and the reduction of the formamide intermediate to monomethylamine as the rate

• -determining step. This work can contribute significantly expanding the applications of N-substituted carbonylimidazoles. Keywords: amines; carboxylic acids; isocyanates; monomethylamines; N-substituted carbonylimidazoles; reduction; Introduction N-Methylamines are widely found in natural products, fine

First example of organocatalysis by cathodic N-heterocyclic carbene generation and accumulation using a divided electrochemical flow cell

• Daniele Rocco,
• Ana A. Folgueiras-Amador,
• Richard C. D. Brown and
• Marta Feroci

Beilstein J. Org. Chem. 2022, 18, 979–990, doi:10.3762/bjoc.18.98

• used as organocatalyst in two classical umpolung reactions of cinnamaldehyde: its cyclodimerization and its oxidative esterification. Keywords: Breslow intermediate; cathodic reduction; flow electrochemistry; N-heterocyclic carbene; oxidative esterification; Introduction Ionic liquids (ILs) are well

• can be modified by the presence of a base or by a single electron cathodic reduction of the C–H between nitrogen atoms of the imidazolium ring (Scheme 1), inducing the formation of a N-heterocyclic carbene (NHC) [7][8]. In recent years, NHCs have achieved great success: they have been frequently used

• reduction of an imidazolium cation to NHC, in an undivided cell under flow conditions, coupled with the anodic generation of Cu(I) from a sacrificial anode to yield the corresponding N-heterocyclic carbene complex [34][35]. In this case, irreversible capture of the NHC by the metallic cation prevented NHC

Electrochemical and spectroscopic properties of twisted dibenzo[g,p]chrysene derivatives

• Tomoya Imai,
• Ryuhei Akasaka,
• Naruhiro Yoshida,
• Toru Amaya and
• Tetsuo Iwasawa

Beilstein J. Org. Chem. 2022, 18, 963–971, doi:10.3762/bjoc.18.96

• investigate the reduction behaviour, DBC-S(O)2Me was measured in the low potential region. A peak, which appeared to be the one-electron reduction peak, was observed at −2.25 V (see Figure S1 in Supporting Information File 1). Finally, the CV of the silole-fused DBC-Si was investigated and the results

Electroreductive coupling of 2-acylbenzoates with α,β-unsaturated carbonyl compounds: density functional theory study on product selectivity

• Naoki Kise and
• Toshihiko Sakurai

Beilstein J. Org. Chem. 2022, 18, 956–962, doi:10.3762/bjoc.18.95

• by cyclic voltammetry (Table 3) and acceptors 2 revealed no reduction peaks from 0 to −2.00 V vs SCE [5][6]. Therefore, this electroreductive coupling is initiated by the reduction of compounds 1. There are two possible reaction mechanisms for the reductive coupling of 1 with 2a as illustrated in

• Scheme 5. The first one is a radical addition of O-trimethylsilyl radical A, which is formed by a one-electron reduction of 1 and subsequent O-trimethylsilylation, to 2a and a following one-electron reduction of the resultant radical B to give enolate anion D (path a). The second one is an anionic

• addition of an O-trimethylsilyl anion C, which is formed by a two-electron reduction of substrate 1 and O-trimethylsillylation, to 2a (path b). Unlike the two reactions previously reported by us that are presumed to proceed with the addition of an anion species (Scheme 1 and Scheme 2) [5][6], methyl

Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

• Valentin H. K. Fell,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Eman J. Hussien and
• Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

• Equation 3) [65][66]: In which Eox is the half-wave potential of the first oxidation signal, and Ered is the half-wave potential of the first reduction signal. Ferrocene was used as the internal standard and its HOMO was taken to be −4.8 eV [67]. With these values, the frontier orbital energy levels of EtH

• more negative. This can be attributed to the presence of the electron-withdrawing keto groups [3][20]. In contrast to compounds 2–4, which showed poor reversibility for oxidation and reduction, EtH-T-DI-DTT shows excellent electrochemical stability. Two sequential reversible oxidations can be seen in

• Figure 9, for the generation of a radical cation and dication at half-wave potential values of +0.65 V (ΔEp = 0.05 V) and +0.87 V (ΔEp = 0.06 V), respectively. Two reduction waves, corresponding to the radical anion and dianion, can be seen at the half-wave potentials of −1.51 V (ΔEp = 0.06 V) and −1.64

Morita–Baylis–Hillman reaction of 3-formyl-9H-pyrido[3,4-b]indoles and fluorescence studies of the products

• Nisha Devi and
• Virender Singh

Beilstein J. Org. Chem. 2022, 18, 926–934, doi:10.3762/bjoc.18.92

• ester 4a–e in high yield (83–87%) and ester functionality reduction with LiAlH4 in dry THF yielded the alcohols 5a–e in excellent yield (90–98%). The required 3-formyl-9H-β-carbolines 6a–e were obtained in 73–88% yield by oxidizing the alcohol derivatives 5a–e with MnO2 in dry DCM. The present

Anti-inflammatory aromadendrane- and cadinane-type sesquiterpenoids from the South China Sea sponge Acanthella cavernosa

• Shou-Mao Shen,
• Qing Yang,
• Yi Zang,
• Jia Li,
• Xueting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 916–925, doi:10.3762/bjoc.18.91

• . X-ray crystallographic analysis. Compound 2 was crystallized from MeCN at 4 °C. The crystallographic data for compound 2 was collected on a Bruker D8 Venture diffractometer using Cu Kα radiation (λ = 1.54178 Å). The collected data integration and reduction were processed with SAINT V8.37A software