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

• responsiveness, acidofluorochromism, AIEE, and enhanced electrochromic performance. One effective approach, as demonstrated by Moshkina et al., involved introducing CN and fluorine substitutions on the Qx core to give Qx69 (Figure 8). This modification resulted in red-shifted absorption and emission maxima

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

• was obtained for BPy-p3C due to the bulkier donor, leading to a more twisted D–A geometry than that of BPy-pTC. Hence, BPy-p3C exhibited aggregation-induced enhanced emission (AIEE) in a THF/water mixture. Interestingly, the singlet–triplet energy gap (ΔEST) was reduced for both compounds in the

• ΔEST tuning in solution and in an aggregated state, including the aggregation-induced enhanced emission (AIEE) characteristics. Further, solid-phase fluorescence switching by alternatingly adding acid and base vapors demonstrated the sensing ability. Therefore, the current study deciphers the role of

• , facilitating the photon upconversion from the T1 to the S1 state through an RISC process. Aggregation-induced enhanced emission (AIEE) In order to determine the molecular aggregate formation of BPy-pTC and BPy-p3C and the impact on the optical properties, we carried out aggregation studies in THF/water

Syntheses of novel pyridine-based low-molecular-weight luminogens possessing aggregation-induced emission enhancement (AIEE) properties

• Masayori Hagimori,
• Tatsusada Yoshida,
• Yasuhisa Nishimura,
• Yukiko Ogawa and
• Keitaro Tanaka

Beilstein J. Org. Chem. 2022, 18, 580–587, doi:10.3762/bjoc.18.60

• -induced emission enhancement (AIEE) properties in aqueous media. Compounds 4a and 4e, bearing electron-withdrawing groups (Br and CF3, respectively) showed 7.0 and 15 times fluorescence enhancement. Time-dependent density functional theory (TD-DFT) calculations were performed to gain better insight into

• the electronic nature of the compounds with and without AIEE properties. Keywords: acceptor–donor–acceptor; AIEE; low molecular weight; one-pot reaction; ((pyridin-2-yl)amino)maleimide; TD-DFT calculation; Introduction Fluorescent compounds have attracted considerable attention as functional

• -concentration solutions, and their emission efficiency, chromogenic properties, and light sensitivity decrease rapidly [5][6]. In recent years, contrary to conventional fluorescent compounds, aggregation-induced emission enhancement (AIEE)-based compounds that exhibit strong fluorescence in aggregate structures

Recent developments and trends in the iron- and cobalt-catalyzed Sonogashira reactions

• Surendran Amrutha,
• Sankaran Radhika and
• Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 262–285, doi:10.3762/bjoc.18.31

• ) moiety since it can easily undergo aggregation-induced emission enhancement (AIEE). The self-assembly of the HPB derivative resulted in the formation of fluorescent aggregates, which can act as a stabilizer or as a reactor for the development of α-Fe2O3 nanoparticles at room temperature. The catalytic

Naphthalonitriles featuring efficient emission in solution and in the solid state

• Sidharth Thulaseedharan Nair Sailaja,
• Iván Maisuls,
• Jutta Kösters,
• Alexander Hepp,
• Andreas Faust,
• Jens Voskuhl and
• Cristian A. Strassert

Beilstein J. Org. Chem. 2020, 16, 2960–2970, doi:10.3762/bjoc.16.246

• substitution and environment is reported with potential applications in sensing, bioimaging and optoelectronics. Keywords: aggregation caused quenching (ACQ); aggregation-induced emission enhancement (AIEE); naphthalonitriles (NCNs); solution and solid state emitters (SSSE); solvent quenching (SQ

• singlet state. In the case of H, the quantum yield rises for increasing water content from 0% to 70%, which is attributed to the AIEE effect. Once it reaches 70%, a growing water fraction leads to an ACQ effect and hence the quantum yield decreases from 80% onwards (Table 2). A similar trend is observed

• in the cases of Me and t-Bu compounds, where a gradual bathochromic shift in emission is observed with growing water fraction (Figures S35 and S36, Supporting Information File 1), pointing to a slight charge-transfer character of the emissive state. These compounds show a prominent AIEE upon

Synthesis and properties of quinazoline-based versatile exciplex-forming compounds

• Rasa Keruckiene,
• Simona Vekteryte,
• Ervinas Urbonas,
• Matas Guzauskas,
• Eigirdas Skuodis,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101

• ; quinazoline; Introduction Organic luminescent materials are extensively used in a wide range of optoelectronic devices. For the design of compounds, potentially exhibiting properties such as bipolar charge transport, delayed fluorescence or aggregation-induced emission enhancement (AIEE), a useful strategy

Emission solvatochromic, solid-state and aggregation-induced emissive α-pyrones and emission-tuneable 1H-pyridines by Michael addition–cyclocondensation sequences

• Natascha Breuer,
• Irina Gruber,
• Christoph Janiak and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2019, 15, 2684–2703, doi:10.3762/bjoc.15.262

• the solid state. This finding suggests that by restricting intramolecular motion and vibration, which enables radiation-less deactivation of the excited state [61], an AIE (aggregation‐induced emission) or AIEE (aggregation-induced enhanced emission), might become operative [62][63][64]. The AIE or

• AIEE effect was assessed by measuring the emission spectra of α-pyrone 6e in THF/water at variable ratios (Figure 15). In pure THF α-pyrone 6e displays an emission maximum at 644 nm with a relative intensity of 54. The addition of water first quenches the fluorescence and at a water/THF ratio of 80

• % aggregates are formed and the emission maximum is shifted to 632 nm. The maximal relative intensity of 130 is reached for a ratio of 85%, which is more intense than in pure THF, therefore, an AIEE effect occurs. Further increasing the water content slightly quenches the emission. Computational studies