Computational model predicts protein binding sites of a luminescent ligand equipped with guanidiniocarbonyl-pyrrole groups

• Neda Rafieiolhosseini,
• Matthias Killa,
• Thorben Neumann,
• Niklas Tötsch,
• Jean-Noël Grad,
• Alexander Höing,
• Thies Dirksmeyer,
• Jochen Niemeyer,
• Christian Ottmann,
• Shirley K. Knauer,
• Michael Giese,
• Jens Voskuhl and
• Daniel Hoffmann

Beilstein J. Org. Chem. 2022, 18, 1322–1331, doi:10.3762/bjoc.18.137

• interactions with other proteins. Here, we use a computational approach to predict the binding sites of the designed hybrid compound featuring aggregation-induced emission luminophores as a potential supramolecular ligand for 14-3-3ζ in the presence and absence of C-Raf peptides. Our results suggest that the

• novel luminophores tailor-made for different applications. One unique, promising class of compounds, the so-called aggregation-induced emitters (AIE) have been used for a wide range of applications, e.g., in OLEDs, liquid crystals [17], stimuli responses, bioassays, protein and ion detection or imaging

• [15][18]. In contrast to classical luminophores, these compounds typically show emission “on” behavior upon aggregation or binding, which can be explained by a restriction of motion. In this contribution, we designed a hybrid compound featuring AIE luminophores based on aromatic thioethers [19] as a

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

• films, the emission for both compounds are red-shifted and significantly quenched (Figure S28 in Supporting Information File 1); indeed, the ΦPL for the neat film of DiKTa-OBuIm is only 9% while we could not ascertain a reliable value for DiKTa-DPA-OBuIm. Severe aggregation-caused quenching of the

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

• base fumes, etc. [10][11]. However, the fluorescence quantum yield of such emitters in the solid state is relatively low due to the aggregation-caused quenching (ACQ) effect [12][13][14] and limits practical applications. Hence, metal-free emitters with high photoluminescence quantum yield (PLQY) in

• metal-based emitters in organic light-emitting diode (OLED) devices [18]. Nevertheless, many TADF emitters suffer from quenching of the emission due to the aggregation-caused quenching effect [19][20]. The strong π–π-stacking interactions in the solid or aggregated state may lead to emission quenching

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

• compound, EtH-T-DI-DTT, consisting of seven, fused ring systems, with an electron-rich central DTT core, flanked by electron-withdrawing keto groups. Absorption studies in solution and in the solid state show strong aggregation of the molecules in films. EtH-T-DI-DTT shows excellent redox stability with

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

• Prodip Howlader and
• Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62

• heteromeric complexes by Issacs’ classification [32] of two main categories: (a) social self-sorting, which involves the assembly of different species, and (b) narcissistic self-sorting, which only involves aggregation of the same component. Over the past few years, a variety of social self-sorting protocols

• , introduced by Lehn, uses maximum site occupancy to afford heteroleptic aggregates [35]. While this principle is limited, the charge-separation approach by Stang is of much wider use [36]. Probably, most contributions in the literature, though, are based on using steric constraints in heteroleptic aggregation

• , since a variety of heteroleptic aggregation protocols have been developed by Schmittel [37] (for copper(I), zinc(II), cadmium(II), mercury(II) ions) and Yoshizawa/Fujita [38] (for palladium(II) ion) that involve pyridine-derived ligands. Highly innovative are the approaches for terpyridine-based

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

• photophysically and computationally. The photophysical studies revealed that all the synthesized compounds exhibited fluorescence in organic solvents, while N-methyl-4-((pyridin-2-yl)amino)-substituted maleimide derivatives 4a–e, which are based on an acceptor–donor–acceptor (A–D–A) system, exhibited aggregation

• -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

• quenched due to aggregation-caused quenching (ACQ) [10]. Generally, the restriction of intermolecular π–π interactions in highly planar compounds plays a key role in aggregate structures exhibiting fluorescence [5][6][10]. In addition, intramolecular mechanisms, such as intramolecular rotation (RIR

Bioinspired tetraamino-bisthiourea chiral macrocycles in catalyzing decarboxylative Mannich reactions

• Hao Guo,
• Yu-Fei Ao,
• De-Xian Wang and
• Qi-Qiang Wang

Beilstein J. Org. Chem. 2022, 18, 486–496, doi:10.3762/bjoc.18.51

• out to be better. A suitable reaction concentration (0.1–0.2 M) was found to be important. A very high or low reaction concentration led to decreased stereoselectivity probably due to the existence of catalyst aggregation or background reactions (Table 3, entries 8–10). Substrate scope Having

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

• ). The PL spectrum is similar to that in a CBP host matrix (vide infra). The compound 1 showed an aggregation-induced emission (AIE) behavior in a THF/water system, showing a more red-shifted emission peak at around λem = 600 nm when compared with the as-prepared solid state (Figure S2 in Supporting

• Information File 1). This indicates that in the as-prepared state and aggregation state the molecular stacking modes should be quite different from each other. Time-resolved spectroscopic analysis To investigate the delayed fluorescence behavior of the D–A compound 1, more detailed photophysical studies were

Tetraphenylethylene-embedded pillar[5]arene-based orthogonal self-assembly for efficient photocatalysis in water

• Zhihang Bai,
• Krishnasamy Velmurugan,
• Xueqi Tian,
• Minzan Zuo,
• Kaiya Wang and
• Xiao-Yu Hu

Beilstein J. Org. Chem. 2022, 18, 429–437, doi:10.3762/bjoc.18.45

• supramolecular self-assembled nanosystem based on host–guest interactions between water-soluble tetraphenylethylene-embedded pillar[5]arene (m-TPEWP5) and ammonium benzoyl-ʟ-alaninate (G) in an aqueous medium. The obtained assembly of m-TPEWP5 and G showed aggregation-induced emission (AIE) via the blocking of

• photosynthesis and exhibited a high catalytic efficiency for the photocatalytic dehalogenation reaction of various bromoketone derivatives with good yields in short reaction time in water. Keywords: aggregation-induced emission; Förster resonance energy transfer; host–guest interaction; photocatalysis

• light irradiation. In addition, the AIE donor molecules allowed an ordered arrangement of the loaded negatively charged dye acceptor on the positively charged surface, which might avoid aggregation-caused quenching effects and produced better catalytic efficiency. These results revealed that the m

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

Study on the interactions between melamine-cored Schiff bases with cucurbit[n]urils of different sizes and its application in detecting silver ions

• Jun-Xian Gou,
• Yang Luo,
• Xi-Nan Yang,
• Wei Zhang,
• Ji-Hong Lu,
• Zhu Tao and
• Xin Xiao

Beilstein J. Org. Chem. 2021, 17, 2950–2958, doi:10.3762/bjoc.17.204

• addition, the UV–vis spectrum in Figure 4a shows that the absorbance of TBT keeps on the decrease (ΔA = 0.623) without red shift or blue shift in the presence of Q[8]. Both of the above phenomena show that Q[8] interacted with the “arm” of TBT and produced precipitation due to aggregation, which is also

Effect of a twin-emitter design strategy on a previously reported thermally activated delayed fluorescence organic light-emitting diode

• Ettore Crovini,
• Zhen Zhang,
• Yu Kusakabe,
• Yongxia Ren,
• Yoshimasa Wada,
• Bilal A. Naqvi,
• Prakhar Sahay,
• Tomas Matulaitis,
• Stefan Diesing,
• Ifor D. W. Samuel,
• Wolfgang Brütting,
• Katsuaki Suzuki,
• Hironori Kaji,
• Stefan Bräse and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2021, 17, 2894–2905, doi:10.3762/bjoc.17.197

• (Supporting Information File 1, Figure S5a) with a corresponding ΦPL of 29% under N2. The significantly red-shifted emission in the PMMA film compared to that in toluene coupled with a significantly lower ΦPL is suggestive that aggregation-caused quenching is prevalent in this host matrix. Transient PL

Adjusting the length of supramolecular polymer bottlebrushes by top-down approaches

• Tobias Klein,
• Franka V. Gruschwitz,
• Maren T. Kuchenbrod,
• Ivo Nischang,
• Stephanie Hoeppener and
• Johannes C. Brendel

Beilstein J. Org. Chem. 2021, 17, 2621–2628, doi:10.3762/bjoc.17.175

• aggregation of Nagg ≈ 1,200 and a length of 110 nm for BTU (assuming four units per cross-section), as well as a weight-average molar mass of Mw = 4,406,000 g⋅mol−1, corresponding to a number of aggregation of Nagg ≈ 490 and a length of 120 nm (assuming two units per cross-section) for BTP, could be observed

• , corresponding to a number of aggregation of Nagg = 1400 and a length of 125 nm for BTU (assuming four units per cross-section). For BTP, a weight-average molar mass of Mw = 2,910,000 g⋅mol−1, corresponding to a number of aggregation of Nagg = 440 and a length of 80 nm (assuming two units per cross-section) was

Synthesis of new bile acid-fused tetrazoles using the Schmidt reaction

• Dušan Đ. Škorić,
• Olivera R. Klisurić,
• Dimitar S. Jakimov,
• Marija N. Sakač and
• János J. Csanádi

Beilstein J. Org. Chem. 2021, 17, 2611–2620, doi:10.3762/bjoc.17.174

• material [4][5][6][7]. Aggregation and interactions with the cell membrane of bile acid molecules can alter drug action [8][9]. Our previous work showed that bile acids could interact with certain drug molecules and improve their biological activity [10][11]. To evade the membranolytic action of natural

• obtained in this way were subjected to antiproliferative activity testing in vitro. It is worth mentioning that the fused tetrazole derivatives of bile acids may possess better hydrophobic–hydrophilic balance, important for aggregation properties, which could be an interesting topic for future research

Post-functionalization of drug-loaded nanoparticles prepared by polymerization-induced self-assembly (PISA) with mitochondria targeting ligands

• Janina-Miriam Noy,
• Fan Chen and
• Martina Stenzel

Beilstein J. Org. Chem. 2021, 17, 2302–2314, doi:10.3762/bjoc.17.148

• be taken into account that the drug can interfere with the block copolymer aggregation. Alternatively, the use of reactive polymers for the polymerization creates a functional anchor to enable post-functionalization of the PISA nanoparticles with drugs such as doxorubicin [35][36]. In a different

• and without triphenylphosphonium (TPP) as mitochondria targeting units. In order to keep the aggregation number, and therefore the size of the nanoparticle, constant, we opted to post-functionalize the nanoparticles with TPP to facilitate the study of the effect of TPP only. Aim of this project is to

• way to ensure high end group fidelity. This is of course true, but it also needs to be considered that the presence of the end group will influence the PISA process and results in aggregation numbers and particle sizes that are very different to the ones obtained with unmodified RAFT agent. Due to the

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

Catalyzed and uncatalyzed procedures for the syntheses of isomeric covalent multi-indolyl hetero non-metallides: an account

• Ranadeep Talukdar

Beilstein J. Org. Chem. 2021, 17, 2102–2122, doi:10.3762/bjoc.17.137

• the strong base led to the formation of the over-aminated product 168 (Scheme 22b) [110]. Alzheimer’s disease is caused by the β-amyloid-42 aggregation in brain tissue [111][112]. In 2017, Sreenivasachary synthesized a library of 6,5’- and 6,6’-bis(indolyl)amines and other similar 7-azaindole

Progress and challenges in the synthesis of sequence controlled polysaccharides

• Giulio Fittolani,
• Theodore Tyrikos-Ergas,
• Denisa Vargová,
• Manishkumar A. Chaube and
• Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

• modification can be prepared. Strategically introduced PGs can be selectively removed to insert a branch or a chemical modification. However, to date, this approach has suffered dramatically from the severe aggregation and insolubility of cellooligosaccharides, permitting to obtain only relatively short

• , fluorine, and carboxymethyl groups, prevented the formation of insoluble aggregates by disrupting hydrogen-bond networks. Dramatic differences in the conformation (e.g., radius of gyration and glycosidic bond conformation) and aggregation behaviour (i.e., crystallinity and solubility) were observed for

Chemical approaches to discover the full potential of peptide nucleic acids in biomedical applications

• Nikita Brodyagin,
• Martins Katkevics,
• Venubabu Kotikam,
• Christopher A. Ryan and
• Eriks Rozners

Beilstein J. Org. Chem. 2021, 17, 1641–1688, doi:10.3762/bjoc.17.116

• vulnerabilities. Limited water solubility, especially for purine rich sequences, was noted in early studies. To improve water solubility and decrease aggregation, typical PNA designs place a lysine at the C-terminus (Figure 1) introducing a second positive charge in addition to the charge at the N-terminus of PNA

• folding in compact structures and aggregation in concentrated solutions [13]. Other bottlenecks for in vivo applications of PNA have been poor cellular uptake and unfavorable pharmacokinetics [14][15][16]. Unmodified PNAs are not taken up by eukaryotic cells in vitro and are cleared rapidly (within 10–30

Recent advances in the application of isoindigo derivatives in materials chemistry

• Andrei V. Bogdanov and
• Vladimir F. Mironov

Beilstein J. Org. Chem. 2021, 17, 1533–1564, doi:10.3762/bjoc.17.111

• = 0.07 cm2⋅V−1⋅s−1. Isoindigo-based sensor devices Isoindigo derivatives have begun to find an application in the design of sensor devices for the detection of simple and complex molecules in various aggregation states. Thus, it was shown that polymer structures based on isoindigo and thiophene 59a,b and

Synthesis of dibenzosuberenone-based novel polycyclic π-conjugated dihydropyridazines, pyridazines and pyrroles

• Ramazan Koçak and
• Arif Daştan

Beilstein J. Org. Chem. 2021, 17, 719–729, doi:10.3762/bjoc.17.61

• exhibit photophysical properties such as photosensitization [13], fluorescence, and aggregation-induced emission (AIE) [14][15][16]. π-Conjugated polycyclic hydrocarbons (CPHs) containing polycyclic heteroaromatic molecules (PHAs) and aza-polycyclic aromatic hydrocarbons (aza-PAHs) have been attracting

Biochemistry of fluoroprolines: the prospect of making fluorine a bioelement

• Vladimir Kubyshkin,
• Rebecca Davis and
• Nediljko Budisa

Beilstein J. Org. Chem. 2021, 17, 439–460, doi:10.3762/bjoc.17.40

• folding kinetic pathways can also lead to aggregation and misfolding issues, affecting the protein production. 2.7 Other properties The acid–base transitions also appear altered in fluoroprolines primarily due to the electron-withdrawing effect of the fluorine atoms (Table 2) [16][19][55][57][58]. This

• relies on its production, which is mainly achieved via living cells. If fluoroprolines alter the protein folding, a misfolded sample would usually be prone to aggregation and/or degradation by the cellular machinery. This may be seen as a lack of protein production or as the protein being insoluble. Only

• -Flp), 3) a lack of interaction with chaperones, 4) misfolding that leads to aggregation, 5) an inhibitory effect of the target protein on the cellular machinery and 6) misfolding that leads to rapid degradation of the protein, to name a few. A misfolding can occur for reasons such as an altered

¹⁹F NMR as a tool in chemical biology

• Diana Gimenez,
• Aoife Phelan,
• Cormac D. Murphy and
• Steven L. Cobb

Beilstein J. Org. Chem. 2021, 17, 293–318, doi:10.3762/bjoc.17.28

• difficulties associated with performing multidimensional experiments at a fast enough rate to follow the aggregation process accurately. Despite these aforementioned challenges the Marsh laboratory has recently demonstrated the utility of 19F NMR to access direct, sensitive and real-time observation of amyloid

• fibril formation, enabling the elucidation of the underlying mechanics of peptide fibrillation. To study the aggregation mechanism of the model Aβ-peptide, a well-known amyloidogenic peptide related to Alzheimer’s disease, Marsh and collaborators synthesized a 19F-labelled Aβ1−40 peptide version in which

• methionine at position 35 was replaced by tfmMet (Aβ1−40-tfmMet35) [9][62]. The aggregation process was then monitored by 19F NMR over a period of several weeks [62]. Upon analysis, formation of at least six spectroscopically distinguishable intermediates could be detected during fiber formation (Figure 10

Multiswitchable photoacid–hydroxyflavylium–polyelectrolyte nano-assemblies

• Alexander Zika and
• Franziska Gröhn

Beilstein J. Org. Chem. 2021, 17, 166–185, doi:10.3762/bjoc.17.17

• cationic building blocks Flavy and poly(allylamine) are mixed first, the aggregation yields clearly polydisperse ternary samples (Table 8 and Table 9). For understanding, it is of interest to consider the intermediate bi-component system, which already leads to polydisperse samples for loading ratios l

Insight into functionalized-macrocycles-guided supramolecular photocatalysis

• Minzan Zuo,
• Krishnasamy Velmurugan,
• Kaiya Wang,
• Xueqi Tian and
• Xiao-Yu Hu

Beilstein J. Org. Chem. 2021, 17, 139–155, doi:10.3762/bjoc.17.15

• this supramolecularly driven photopolymerization (0.0305 min−1) could be enhanced by decreasing the aggregation of PDI via host–guest interactions. Recently, Wang and co-workers fabricated the orthogonal supramolecular ternary self-assembled system 27@CB[7]/EY via host–guest interactions between CB[7