HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines

• Luan A. Martinho and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2024, 20, 628–637, doi:10.3762/bjoc.20.55

• is known for its chemical and thermal stability. Herein, we report a straightforward approach to the GBB-3CR using HPW as catalyst in ethanol under microwave (μw) heating. This convenient environmentally benign methodology is broad in scope, provides the heterobicyclic products in high yields (up to

• green catalyst with greater chemical and thermal stability in comparison to other heteropolyacids [43]. HPW has been shown to catalyze MCRs in the synthesis of heterocyclic compounds with high efficiency and chemoselectivity (Figure 2), including functionalized benzo[c]chromeno[2,3-a]phenazine [44

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• the organic product along with inorganic species [41][42][43][44]. Over the years, many efforts were thus devoted to the synthesis of thiepine derivatives with increased thermal stability, with the aim to disfavor the formation of the transient thianorcaradiene intermediate as a way to prevent the

• previously. Importantly, photoirradiation at 254 nm or 365 nm failed to induce any chalcogen extrusion. When thermal activation was tested on solid samples, oxepine 26a, thiepine 28b and thiepine S,S-dioxide 30b were not converted upon heating at 250 °C for 2 hours, thus highlighting their high thermal

• stability. Conversely, selenepine 28c and selenepine Se-oxide 29c were quantitatively converted into the seco-HBC 31 by thermal activation at 200 °C for 5 min, as evidenced by UV–visible absorption and HPLC monitoring. SO-extrusion from thiepine S-oxide 29b was also successfully triggered in the solid state

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• film of compound 8 showed a more than twice lower PLQY which was enhanced using the mCP host. The other compounds showed similar PLQY trends (Table 1). Thermal properties The thermal stability and phase transitions of the synthesized derivatives 6–9 were investigated utilizing thermogravimetric

• of compounds 6–9 was observed. The Tg values of the derivatives increase gradually by 5–12 °C starting from compound 6 which possesses the lowest molecular weight (M = 1566 g/mol) up to compound 9 which possesses the highest M value (2424 g/mol) [13]. A high thermal stability was observed for all

• with pyridine-3,5-dicarbonitrile fragments demonstrated a range of attractive properties, including efficient TADF, favorable charge transport, and thermal stability. These findings open up new possibilities for the design and development of high-performance OLEDs and other organic electronic devices

Thienothiophene-based organic light-emitting diode: synthesis, photophysical properties and application

• Recep Isci and
• Turan Ozturk

Beilstein J. Org. Chem. 2023, 19, 1849–1857, doi:10.3762/bjoc.19.137

• under N2 atmosphere (Figure 4). The initial mass loss (5%) around 120 °C could be due to residual water and/or solvent. The highest decomposition was observed at around 405 oC and 14% of DMB-TT-TPA (8) remained without ash up to 750 °C, indicating that the compound has an excellent thermal stability

• . The high thermal stability is profitable for the preparation of stable and durable OLED devices. Computational chemistry Ground-state geometry optimization of DMB-TT-TPA (8) was performed using density functional theory (DFT) calculations with the Gaussian 16 software at the B3LYP/6-31G (d,p) level

Charge carrier transport in perylene-based and pyrene-based columnar liquid crystals

• Alessandro L. Alves,
• Simone V. Bernardino,
• Carlos H. Stadtlober,
• Edivandro Girotto,
• Giliandro Farias,
• Rodney M. do Nascimento,
• Sergio F. Curcio,
• Thiago Cazati,
• Marta E. R. Dotto,
• Juliana Eccher,
• Leonardo N. Furini,
• Hugo Gallardo,
• Harald Bock and
• Ivan H. Bechtold

Beilstein J. Org. Chem. 2023, 19, 1755–1765, doi:10.3762/bjoc.19.128

• derivatives are among the most investigated due to their easy functionalization, high chemical and thermal stability, strong photoluminescence, and n-type semiconductor character. They tend to adopt columnar organization due to the strong π–π interaction of the rigid cores, providing a path for the efficient

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• morphology on Qx26 and Qx27, employing indacenodithiophene, Qx and rhodanine as donor, acceptor and end group, respectively. The incorporation of specific side chains facilitated improved thermal stability, solubility, and broad absorption spectra (300–750 nm), narrow bandgaps (1.68–1.74 eV) and PCEs in the

• properties of Qx45 series by incorporating electron-donating (methyl) and electron-withdrawing groups (bromo and nitro) (Figure 6). The observation of low-lying LUMO levels (−3.29 to −3.43 eV) and thermal stability in these dyes suggested their potential as efficient ETMs [50]. Similarly, Singh et al

A deep-red fluorophore based on naphthothiadiazole as emitter with hybridized local and charge transfer and ambipolar transporting properties for electroluminescent devices

• Suangsiri Arunlimsawat,
• Patteera Funchien,
• Pongsakorn Chasing,
• Atthapon Saenubol,
• Taweesak Sudyoadsuk and
• Vinich Promarak

Beilstein J. Org. Chem. 2023, 19, 1664–1676, doi:10.3762/bjoc.19.122

• scanning calorimetry (DSC) under N2 atmosphere at a scanning rate of 10 °C min−1. As displayed in Figure 5a, the compound has a high thermal stability with a decomposition temperature at 5% weight loss (T5d) of 498 °C, a glass transition temperature (Tg) of 236 °C, and a melting temperature (Tm) of 376 °C

A series of perylene diimide cathode interlayer materials for green solvent processing in conventional organic photovoltaics

• Kathryn M. Wolfe,
• Shahidul Alam,
• Eva German,
• Fahad N. Alduayji,
• Maryam Alqurashi,
• Frédéric Laquai and
• Gregory C. Welch

Beilstein J. Org. Chem. 2023, 19, 1620–1629, doi:10.3762/bjoc.19.119

• transport, exhibit high thermal stability, are highly tunable in terms of their physical and chemical properties, and can be readily doped thereby increasing electronic conductivity. Some of the most widely used PDI materials for CILs are PDIN [14], PDINN [15], and PDINO (Figure 1a) [14][15]. Past work in

Synthesis of 5-arylidenerhodanines in L-proline-based deep eutectic solvent

• Stéphanie Hesse

Beilstein J. Org. Chem. 2023, 19, 1537–1544, doi:10.3762/bjoc.19.110

• promising emerging class of green solvents as they offer numerous advantages, such as low volatility, non-flammability, chemical and thermal stability, recyclability, and above all a good biodegradability [10]. Moreover, their synthesis is usually easy and cheap as DES are formed by simply mixing an H-bond

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• the NHC–CuN(SiMe3)2 complexes 42, 45, and 48, respectively. All synthesized complexes were characterized by TGA to explain their thermal behavior. The impact of the N-allyl substituent and backbone character on volatility and thermal stability of the copper amides were investigated and it was found

• that the saturated copper–carbene complexes exhibit a higher thermal stability as compared to the unsaturated copper–carbene complexes. In another interesting research paper, César et al., in 2015, reported the synthesis of the mesoionic 5-acetylimidazolium-4-olate 49 which served as a precursor for an

Organic thermally activated delayed fluorescence material with strained benzoguanidine donor

• Alexander C. Brannan,
• Elvie F. P. Beaumont,
• Nguyen Le Phuoc,
• George F. S. Whitehead,
• Mikko Linnolahti and
• Alexander S. Romanov

Beilstein J. Org. Chem. 2023, 19, 1289–1298, doi:10.3762/bjoc.19.95

• identical molecular peak ion and C, H, N values within acceptable deviation of 0.4%. The decomposition temperature (Td, corresponds to 5% weight loss) was measured by thermogravimetric analysis (TGA) indicating excellent thermal stability for 4BGIPN with Td = 425 °C, which is similar to the benchmark

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• unit, the ECS state of the NI-PTZ-F-O, NI-PTZ-Ph-O, and NI-PTZ-C5-O was increased by ca. 0.8 eV. Thus, we do not expect TADF for these three dyads, especially in HEX. In polar solvents, such as ACN, no TADF was observed. Thermal stability analysis (thermogravimetry analysis, TGA) The thermal stability

• % thermal weight loss) of each compound were determined as follows: NI-PTZ-F (422 °C), NI-PTZ-Ph (375 °C), NI-PTZ-CH3 (436 °C), NI-PTZ-OCH3 (432 °C), NI-PTZ-F-O (371 °C), NI-PTZ-Ph-O (362 °C), NI-PTZ-C5 (436 °C), NI-PTZ-C5-O (373 °C). The results show that the thermal stability of these compounds is

• excellent, and the thermal stability of dyads containing unoxidized PTZ units is better than those containing oxidized PTZ units. Femtosecond transient absorption (fs-TA) spectra In order to study the CS, charge recombination (CR), and ISC of the compounds, the femtosecond transient spectra were studied

Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis

• Nicoleta G. Hădărugă,
• Gabriela Popescu,
• Dina Gligor (Pane),
• Cristina L. Mitroi,
• Sorin M. Stanciu and
• Daniel Ioan Hădărugă

Beilstein J. Org. Chem. 2023, 19, 380–398, doi:10.3762/bjoc.19.30

• complexes was kneading the components at various molar ratios (1:1:1 and 3:1:1 for β-CD hydrate:hazelnut oil (average molar mass of 900 g/mol):flavonoid). The recovering yields of the ternary complexes were in the range of 51.5–85.3% and were generally higher for the 3:1:1 samples. The thermal stability was

• compounds [5]. The resulting supramolecular inclusion complexes provide enhanced water solubility and bioavailability/bioaccessibility of the nanoencapsulated bioactive compounds, higher oxidative and thermal stability or photostability of labile compounds, and their controlled release [6][7]. Vegetable oil

• apparent water solubility and bioaccessibility of the oil and fat components. The oxidative stability of the polyunsaturated FA glycerides or free FAs is significantly increased by CD nanoencapsulation. Thus, a high thermal stability was obtained for linoleic acid encapsulated into α-CD by co

Inclusion complexes of the steroid hormones 17β-estradiol and progesterone with β- and γ-cyclodextrin hosts: syntheses, X-ray structures, thermal analyses and API solubility enhancements

• Alexios I. Vicatos,
• Zakiena Hoossen and
• Mino R. Caira

Beilstein J. Org. Chem. 2022, 18, 1749–1762, doi:10.3762/bjoc.18.184

• thermogravimetric analyses (TGA) and differential scanning calorimetry (DSC) analyses for the four CD inclusion complexes (Figure 5a–d) primarily indicated their water content and thermal stability, the data for their thermal events being summarised in Table 1. These results were further accompanied by hot stage

• particular (Table 1). Thus, all CD complexes displayed thermal integrity until relatively high temperatures of at least 100 °C, prior to phase transitions and decomposition, indicating acceptable thermal stability for commercial pharmaceutical applications. Further analytical details regarding the TGA, dTGA

1,4,6,10-Tetraazaadamantanes (TAADs) with N-amino groups: synthesis and formation of boron chelates and host–guest complexes

• Artem N. Semakin,
• Ivan S. Golovanov,
• Yulia V. Nelyubina and
• Alexey Yu. Sukhorukov

Beilstein J. Org. Chem. 2022, 18, 1424–1434, doi:10.3762/bjoc.18.148

• in an atypical +4 oxidation state [27][28][29]. Recently, TAAD was used to improve the thermal and photochemical stability of MAPbI3 perovskite films (most likely through coordination of Pb(II) ions) [30]. The disadvantages of 3O-TAADs, however, are limited thermal stability (due to cage opening to

Mechanochemical synthesis of unsymmetrical salens for the preparation of Co–salen complexes and their evaluation as catalysts for the synthesis of α-aryloxy alcohols via asymmetric phenolic kinetic resolution of terminal epoxides

• Shengli Zuo,
• Shuxiang Zheng,
• Jianjun Liu and
• Ang Zuo

Beilstein J. Org. Chem. 2022, 18, 1416–1423, doi:10.3762/bjoc.18.147

• addition, a Lewis basic NEt2 (‒N(CH2CH3)2) group was introduced to the salen scaffold to facilitate purification, enhance catalytic efficiency, and improve the thermal stability, as was shown in the synthesis of fluorescent probes [41][42]. The chelating effect of salen compounds 1 with different metals

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

• broad Bragg reflections at 2θ = 16° and 28°. This suggests a high thermal stability of the g-h-PCN structure, being formed during the mild milling and aging conditions, with no need for annealing. X-ray photoelectron spectroscopy (XPS) To gain insight into the atomic speciation within the structure and

• the pure reaction product. The variations may be ascribed to the oxygen content found by XPS (Figure 2) or that the mechanochemically synthesized material exists in a different spatial configuration to those previously predicted [46][47]. Thermal stability Prior to annealing, g-h-PCN was found to show

• thermal stability upwards of 200 °C through TGA in nitrogen and air (Supporting Information File 1, Figures S6 and S7). The initial loss seen for both samples is attributed to surface-bound water and carbon dioxide. The g-h-PCN300 retains more mass to upwards of 400 °C in both air and nitrogen, however

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

• ] and ease of tunability of properties [11]. Although their thermal stability is lower than their inorganic counterparts [12], their properties, e.g. the HOMO–LUMO gap, can be tailored and fine-tuned by molecular design [3]. Depending on their structure and/or functional groups, they can be designed for

• its phase below its melting point. The limits of thermal stability were recorded by a 5% mass loss at elevated temperatures, as determined by thermal gravimetric analysis (TGA), and found to be 406 °C, indicating a high thermal stability (Figure S18 in Supporting Information File 1). Electrochemistry

Comparative study of thermally activated delayed fluorescent properties of donor–acceptor and donor–acceptor–donor architectures based on phenoxazine and dibenzo[a,j]phenazine

• Saika Izumi,
• Prasannamani Govindharaj,
• Anna Drewniak,
• Paola Zimmermann Crocomo,
• Satoshi Minakata,
• Leonardo Evaristo de Sousa,
• Piotr de Silva,
• Przemyslaw Data and
• Youhei Takeda

Beilstein J. Org. Chem. 2022, 18, 459–468, doi:10.3762/bjoc.18.48

• , where POZ-DBPHZ has the twice higher value which in total should give a much lower performance in the device for 1. Thermal stability To fabricate the OLED devices by thermal evaporation techniques, a high thermal stability is required. To evaluate the effect of the donor number on the thermal stability

• deposition process. However, when compared with the D–A–D counterpart, the Td of 1 is much lower (by 111 °C) than that of POZ-DBPHZ (453 °C) [17]. These data would support that the increase in the sterically hindered donors in emitting molecule suppress intermolecular contact to enhance the thermal stability

• , the one-less number of donor units in the molecular scaffold led to lower solubility in organic solvents and thermal stability, presumably due to the less steric hindrance around the π-extended conjugated acceptor unit with the unsymmetric molecule structure. The OLEDs fabricated with the D–A emitter

Photophysical, photostability, and ROS generation properties of new trifluoromethylated quinoline-phenol Schiff bases

• Inaiá O. Rocha,
• Yuri G. Kappenberg,
• Wilian C. Rosa,
• Clarissa P. Frizzo,
• Nilo Zanatta,
• Marcos A. P. Martins,
• Isadora Tisoco,
• Bernardo A. Iglesias and
• Helio G. Bonacorso

Beilstein J. Org. Chem. 2021, 17, 2799–2811, doi:10.3762/bjoc.17.191

• 4-substituted 4-methoxy-1,1,1-trifluoroalk-3-en-2-ones in a two-step reaction procedure and with satisfactory yields of up to 87%. The prepared 6-aminoquinolines presented promising photophysical properties and high thermal stability [14]. In this sense, the present study aimed to synthesize a novel

In-depth characterization of self-healing polymers based on π–π interactions

• Josefine Meurer,
• Julian Hniopek,
• Johannes Ahner,
• Michael Schmitt,
• Jürgen Popp,
• Stefan Zechel,
• Kalina Peneva and
• Martin D. Hager

Beilstein J. Org. Chem. 2021, 17, 2496–2504, doi:10.3762/bjoc.17.166

• differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The TGA revealed a high thermal stability up to a temperature of 370 °C (for curves see Supporting Information File 1). The temperature was determined at a residual mass of 95%. The DSC on the other hand indicates several thermal

Chemical syntheses and salient features of azulene-containing homo- and copolymers

• Vijayendra S. Shetti

Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139

• subjected to the oxidative polymerization by using ferric chloride to obtain polymers 33–38 in 42–58% yields as shown in Scheme 8. These polymers possessed good thermal stability (Td > 400 °C) and most of them were soluble in organic solvents such as THF, chloroform, dichloromethane, xylene, and toluene

• -dibromo-6-(n-dodecyl)azulene (13) with 2,5-bis(trimethylstannyl)thiophene (44) under Stille reaction conditions produced the polymer 45 in 62% yield (Scheme 10). The Mn and PDI for polymer 45 were 5100 Da and 1.4, respectively and its thermal stability was excellent (Td = 404 °C). Polymer 45 exhibited

• , and 56 displayed good solubility in most of the commonly used organic solvents and GPC analysis revealed their number-average molecular weight (Mn) to be in the range of 25800 to 48600 Da with polydispersity in the range 1.29–1.9. They also exhibited excellent thermal stability as indicated by their