A heteroditopic macrocycle as organocatalytic nanoreactor for pyrroloacridinone synthesis in water

• Piyali Sarkar,
• Sayan Sarkar and
• Pradyut Ghosh

Beilstein J. Org. Chem. 2019, 15, 1505–1514, doi:10.3762/bjoc.15.152

• aggregation tendency. Herein we have extensively explored a multifunctional macrocycle (BATA-MC), comprising bis-amide and tris-amine functionalities as H-bond donor/acceptor moieties, and parallel benzene moieties for aromatic π–π stacking interactions as an organocatalytic nanoreactor for organic

• sites along with H-bonding donor/acceptor site. So, it may also be associated to the nanoreactor to approach the enaminoketone. Then, consecutive cyclization and ring opening of isatin (translactamization) affords intermediate C which undergoes cyclocondensation to furnish the final product F

Mechanochemistry of supramolecules

• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2019, 15, 881–900, doi:10.3762/bjoc.15.86

• –acceptor [2]rotaxanes such as 19 through liquid-assisted mechanochemical milling (Figure 9). The donor–acceptor interaction between the electron-deficient naphthalene diimide moiety and the electron-rich naphthalene moieties embedded in the macrocyclic polyethers played the vital role for the construction

• under milling conditions (30 Hz for 1–2 h). When for example, N-methyl-1,1,-diphenylmethanamine was used as one of the stoppers, diamido [2]rotaxane 17 was obtained with high yield (ca. 87%) [61] (Figure 8). In 2017, Wang and co-workers reported an efficient method for the synthesis of neutral donor

Photochemical generation of the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radical from caged nitroxides by near-infrared two-photon irradiation and its cytocidal effect on lung cancer cells

• Ayato Yamada,
• Manabu Abe,
• Yoshinobu Nishimura,
• Shoji Ishizaka,
• Masashi Namba,
• Taku Nakashima,
• Kiyofumi Shimoji and
• Noboru Hattori

Beilstein J. Org. Chem. 2019, 15, 863–873, doi:10.3762/bjoc.15.84

• extrapolation from the absolute TP cross-section of the parent NPBF (18 GM) at 720 nm [58]. The TP cross-section of 2a was higher than that of 2b by ≈15 GM. This higher GM value may be due to the stronger donor–acceptor character of 2a relative to that of 2b, because the electron-donating alkyl group is located

Diastereo- and enantioselective preparation of cyclopropanol derivatives

• Marwan Simaan and
• Ilan Marek

Beilstein J. Org. Chem. 2019, 15, 752–760, doi:10.3762/bjoc.15.71

• when the same sequence of diastereoselective carbometalation/oxidation was performed on cyclopropenyl ester 1, the in situ-formed donor–acceptor cyclopropanol undergoes a selective ring-opening to provide the acyclic product possessing a quaternary carbon stereocenter [57]. As the enantioselective

Conformational signature of Ishikawa´s reagent using NMR information from diastereotopic fluorines

• Laize A. F. Andrade,
• Lucas A. Zeoly,
• Rodrigo A. Cormanich and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2019, 15, 506–512, doi:10.3762/bjoc.15.44

• natural bond orbital (NBO) [34] analyses at the ωB97X-D/6-311++G(d,p) level [31][32] were performed to obtain the second-order perturbation energies of donor–acceptor interactions. This same level of theory was employed for the chemical shift and SSCC calculations. Structure of Ishikawa´s reagent (1) and

Silanediol versus chlorosilanol: hydrolyses and hydrogen-bonding catalyses with fenchole-based silanes

• Falco Fox,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2019, 15, 167–186, doi:10.3762/bjoc.15.17

• ]) of the transition structure (TS) for the hydrolysis of dichlorosilane 7, 8, 13, [CH2O]2SiCl2 and SiCl4 to the corresponding mono- and diols. Computeda stretching frequencies (ν [cm−1]), lp···σ* [kcal mol−1] and donor acceptor distances (D [Å]) of silanes 7, 8, [CH2O]2SiCl(OH), [CH2O]2Si(OH)2, (OH

Tetrathiafulvalene – a redox-switchable building block to control motion in mechanically interlocked molecules

• Hendrik V. Schröder and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2018, 14, 2163–2185, doi:10.3762/bjoc.14.190

• supramolecular chemistry [28] and for the construction of MIMs [29], the good π-donor properties of TTF are frequently used to template donor–acceptor complexes with π-electron deficient macrocycles. If TTF undergoes oxidation, the π-donating effect decreases, whereas the TTF2+ dication can be considered as a π

• properties which are very helpful for observing the molecular switching in MIMs are charge-transfer bands. The π-donor TTF can form donor–acceptor complexes with π-electron-poor aromatic compounds often indicated by a green color of the solution [33]. Therefore, the assembly and disassembly of these

• solutions due to the donor–acceptor interaction. In later reports, differently substituted TTF derivatives as for example 2, 4, and 5 have been investigated towards their binding to host 3 [24][59][60][61][62][63]. π-Electron-rich TTFs form significantly stronger donor–acceptor complexes as π-electron-poor

Evaluation of dispersion type metal···π arene interaction in arylbismuth compounds – an experimental and theoretical study

• Ana-Maria Preda,
• Małgorzata Krasowska,
• Lydia Wrobel,
• Philipp Kitschke,
• Phil C. Andrews,
• Jonathan G. MacLellan,
• Lutz Mertens,
• Marcus Korb,
• Tobias Rüffer,
• Heinrich Lang,
• Alexander A. Auer and
• Michael Mehring

Beilstein J. Org. Chem. 2018, 14, 2125–2145, doi:10.3762/bjoc.14.187

• intermolecular contacts, as likewise observed in all of the three described polymorphs of Ph3Bi. For compound 3 intermolecular contacts as a result of coordination of the methoxy group to neighboring bismuth atoms are observed overruling Bi···π arene contacts. Compound 5 shows a combination of donor acceptor Bi

• attached to the aryl ligands, which hinder the interactions of the bismuth atom with the aryl ligands of the neighboring molecules (Figure 7). The crystal structure analysis of 5 revealed intermolecular donor acceptor Bi···Cl interactions of Bi1–Cl1b 2.805(7) Å, which are accompanied by Bi···π arene

• structures of 1–5 described above revealed the presence of London dispersion type interactions in the solid state, with bismuth acting as dispersion energy donor (DED) only in some cases. In the absence of strong donor acceptor type interactions a competition between the different types of dispersion

Synthesis and supramolecular self-assembly of glutamic acid-based squaramides

• Juan V. Alegre-Requena,
• Marleen Häring,
• Isaac G. Sonsona,
• Alex Abramov,
• Eugenia Marqués-López,
• Raquel P. Herrera and
• David Díaz Díaz

Beilstein J. Org. Chem. 2018, 14, 2065–2073, doi:10.3762/bjoc.14.180

• conjugated to an aromatic cyclobutenedione ring, can be easily synthesized from different derivatives of squaric acid and amines [1][2][3][4]. The possibility to fabricate chiral squaramide derivatives and their efficient hydrogen bond donor/acceptor ability has driven the pivotal role of these compounds in

Synthesis of 9-arylalkynyl- and 9-aryl-substituted benzo[b]quinolizinium derivatives by Palladium-mediated cross-coupling reactions

• Siva Sankar Murthy Bandaru,
• Darinka Dzubiel,
• Heiko Ihmels,
• Mohebodin Karbasiyoun,
• Mohamed M. A. Mahmoud and
• Carola Schulzke

Beilstein J. Org. Chem. 2018, 14, 1871–1884, doi:10.3762/bjoc.14.161

• positively charged nitrogen atoms and π···π donor–acceptor attractions between the phenyl and pyridinium moieties. In our case, the situation is somehow more complex as the novel compounds bear aromatic substituents (via alkyne spacer) in the benzo[b]quinolizinium 9 position. These aromatic substituents now

• engage in π···π donor–acceptor attractions with the pyridinium moiety (outer most ring of the tricyclic moiety) and the two positively charged nitrogen atoms are per se much further apart due to the larger intramolecular separation between the intermolecularly interacting π-systems. In addition, the

• . Notably, for 2b the phenyl to phenyl π···π interaction of one molecule is not with the same neighbor as the π···π donor–acceptor attraction between the phenyl and pyridinium rings. Therefore, these two distinct π-system-based attractions alternate and form infinite chains of molecules roughly protruding

Preparation and X-ray structure of 2-iodoxybenzenesulfonic acid (IBS) – a powerful hypervalent iodine(V) oxidant

• Irina A. Mironova,
• Pavel S. Postnikov,
• Rosa Y. Yusubova,
• Akira Yoshimura,
• Thomas Wirth,
• Viktor V. Zhdankin,
• Victor N. Nemykin and
• Mekhman S. Yusubov

Beilstein J. Org. Chem. 2018, 14, 1854–1858, doi:10.3762/bjoc.14.159

• . In addition, a water molecule was observed in the crystal structure of 6, which forms two strong hydrogen bonds (≈2.05 Å for O(21)–H(2)···O(11) and ≈2.07 Å for O(21)–H(3)···O(5)) with neighbouring oxygen atoms and two short donor–acceptor interactions with K(1) and K(2) potassium ions. Overall, the

Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis

• Gwendal Grelier,
• Benjamin Darses and
• Philippe Dauban

Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128

• benzoate motif and the alkynyl group are obtained from various acceptor or donor–acceptor diazo compounds 30, while the use of vinyldiazo derivatives 32 leads to enynes 33 arising from the vinylogous addition of the carboxylate. Significantly, the benzoyloxy-alkynylation reaction can be applied to the late

Recent advances in phosphorescent platinum complexes for organic light-emitting diodes

• Cristina Cebrián and
• Matteo Mauro

Beilstein J. Org. Chem. 2018, 14, 1459–1481, doi:10.3762/bjoc.14.124

• between these donor-acceptor groups, namely meta- and para-substitution. As expected, the intramolecular charge transfer character was less prominent in the absorption features of compounds with meta-linkages. Nevertheless, all compounds showed a 3IL/3MLCT emission in the green region, that resembled well

D–A–D-type orange-light emitting thermally activated delayed fluorescence (TADF) materials based on a fluorenone unit: simulation, photoluminescence and electroluminescence studies

• Lin Gan,
• Xianglong Li,
• Xinyi Cai,
• Kunkun Liu,
• Wei Li and
• Shi-Jian Su

Beilstein J. Org. Chem. 2018, 14, 672–681, doi:10.3762/bjoc.14.55

• . China 10.3762/bjoc.14.55 Abstract The design of orange-light emitting, thermally activated, delayed fluorescence (TADF) materials is necessary and important for the development and application of organic light-emitting diodes (OLEDs). Herein, two donor–acceptor–donor (D–A–D)-type orange TADF materials

Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)

• Thanh-Tuân Bui,
• Fabrice Goubard,
• Malika Ibrahim-Ouali,
• Didier Gigmes and
• Frédéric Dumur

Beilstein J. Org. Chem. 2018, 14, 282–308, doi:10.3762/bjoc.14.18

• in the D–A diad is observed, resulting in a drastic reduction of the PLQY and thus of the external quantum efficiency. In the same study, authors examined the case of two TADF emitters based on a donor–acceptor–donor (D–A–D) structure, i.e., T3 and T4, where azasiline was used as the donor and

• in donor-acceptor-based TADF emitters [57]. Considering that the electron acceptor is not symmetrical anymore, positions of the nitrogen atoms will significantly influence the distribution of the electronic cloud and potentially the overlap with the HOMO level. Examination of the electronic

Fluorogenic PNA probes

• Tirayut Vilaivan

Beilstein J. Org. Chem. 2018, 14, 253–281, doi:10.3762/bjoc.14.17

Synthesis and spectroscopic properties of β-meso directly linked porphyrin–corrole hybrid compounds

• Baris Temelli and
• Hilal Kalkan

Beilstein J. Org. Chem. 2018, 14, 187–193, doi:10.3762/bjoc.14.13

• characters, high fluorescence quantum yields and favorable electronic properties. Porphyrin–corrole conjugates have been successfully used as donor–acceptor systems in photoinduced charge separation processes. It was shown that derivatives of these conjugates could be potentially used in photovoltaic

Fluorescent nucleobase analogues for base–base FRET in nucleic acids: synthesis, photophysics and applications

• Mattias Bood,
• Sangamesh Sarangamath,
• Moa S. Wranne,
• Morten Grøtli and
• L. Marcus Wilhelmsson

Beilstein J. Org. Chem. 2018, 14, 114–129, doi:10.3762/bjoc.14.7

• without the acceptor molecule present. This efficiency (E) depends on the distance (RDA) between the donor and acceptor as described in Equation 1: where R0 is the Förster distance (Equation 2), a characteristic distance of the donor–acceptor pair at which the energy transfer efficiency (E) is 50%. As can

• be seen in Equation 2 the Förster distance depends on the quantum yield of the donor (ΦD), the donor/acceptor spectral overlap integral (JDA, overlap between energies of donor emission and acceptor absorption envelope), the refractive index of the medium (n), and importantly the geometric factor (κ

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• base and DMSO as solvent they observed a colouring of the reaction mixture, whereas the reagents are colourless themselves. They suggest that the thiol becomes deprotonated to the respective thiolate anion and subsequently an electron donor–acceptor complex with the aryl halide is formed. Irradiation

• starting materials absorbs visible-light, the mixture of all reagents shows absorption in the visible-light region, which indicates the formation of donor–acceptor complexes. The exact origin of the absorption could not be specified until now. The reaction tolerates diverse functional groups. Electron-rich

Hydrolysis, polarity, and conformational impact of C-terminal partially fluorinated ethyl esters in peptide models

• Vladimir Kubyshkin and
• Nediljko Budisa

Beilstein J. Org. Chem. 2017, 13, 2442–2457, doi:10.3762/bjoc.13.241

• polypeptides is still not fully understood and it may appear controversial in the literature. For example, a donor–acceptor type enhancement of the face-to-face stacking of phenyl- and pentafluorophenyl groups has been suggested [36]; though, subsequent studies of α-helical [37], peptoid [38], and collagen

Preactivation-based chemoselective glycosylations: A powerful strategy for oligosaccharide assembly

• Weizhun Yang,
• Bo Yang,
• Sherif Ramadan and
• Xuefei Huang

Beilstein J. Org. Chem. 2017, 13, 2094–2114, doi:10.3762/bjoc.13.207

• ][13][14], fluorine-supported glycosylation [15][16] and automated solid-phase synthesis [17]. All of these methods use the donor/acceptor premixed approach and preferential activation of the donor is achieved by the higher anomeric reactivity of the donor towards the promoter compared to the acceptor

Intramolecular glycosylation

• Xiao G. Jia and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

• an intermolecular reaction. This is usually credited to the facial selectivity for the glycosyl acceptor attack restricted by the tethering (Scheme 1b). However, the execution of this concept requires additional steps for the preparation of the tethered donor–acceptor combinations, and in some cases

• disaccharide 9 in 74% as a pure 1,2-trans isomer [52]. Expansion of this approach to other positions and sugar series showed that the stereoselectivity could be relaxed, and seemed to be dependent of the donor–acceptor match–mismatch. Thus, when succinoyl was attached to the 6-OH of the galactosyl acceptor

• attachment to the neighboring C-2 position. In contrast, 6,6’-linked donor–acceptor pair 13 led to the formation of the (1→4)-linked regioisomer 15 [64]. Apparently, the rigid phthaloyl tether helps to achieve high regioselectivity because the anomeric center of the activated donor cannot easily reach out

p-tert-Butylthiacalix[4]arenes functionalized by N-(4’-nitrophenyl)acetamide and N,N-diethylacetamide fragments: synthesis and binding of anionic guests

• Alena A. Vavilova and
• Ivan I. Stoikov

Beilstein J. Org. Chem. 2017, 13, 1940–1949, doi:10.3762/bjoc.13.188

• negatively charged substrates. Usually, receptors for anions are charged systems capable of electrostatic interaction with anions [1][44][45] or neutral systems using other types of interactions, such as donor–acceptor interactions, hydrogen bonds, hydrophobic effects, etc. [46][47][48][49][50][51][52][53

Molecular-level architectural design using benzothiadiazole-based polymers for photovoltaic applications

• Vinila N. Viswanathan,
• Arun D. Rao,
• Upendra K. Pandey,
• Arul Varman Kesavan and
• Praveen C. Ramamurthy

Beilstein J. Org. Chem. 2017, 13, 863–873, doi:10.3762/bjoc.13.87

• backbone was also studied. This enhanced planarity led to the highest observed mobility among the reported three polymers as well as to an improvement in the device efficiency by more than 40% for P3. Keywords: bulk heterojunction; donor–acceptor–donor polymer; low band gap polymer; organic photovoltaics

• OPV devices led to a new type of device, the so-called bulk heterojunction (BHJ) solar cells, with improved power-conversion efficiency (PCE) [2][3][4]. A large number of polymer semiconducting materials of donor–acceptor–donor (D–A–D) architecture have been synthesized and used in OPV devices

• parameters to consider for the design of a new donor polymer system. In OPV devices, a bicontinuous layer of a donor and an acceptor material is sandwiched between two electrodes. After the absorption of light, excitons are generated which dissociate towards the interface of the donor–acceptor layer and are

Synthesis and optical properties of new 5'-aryl-substituted 2,5-bis(3-decyl-2,2'-bithiophen-5-yl)-1,3,4-oxadiazoles

• Anastasia S. Kostyuchenko,
• Tatyana Yu. Zheleznova,
• Anton J. Stasyuk,
• Aleksandra Kurowska,
• Wojciech Domagala,
• Adam Pron and
• Alexander S. Fisyuk

Beilstein J. Org. Chem. 2017, 13, 313–322, doi:10.3762/bjoc.13.34

• Gliwice, Poland Faculty of Chemistry , Warsaw University of Technology, Noakowskiego 3, 00-664 Warszawa, Poland Department of Organic Chemistry, Omsk F.M. Dostoevsky State University, 55a Mira pr., 644077 Omsk, Russian Federation 10.3762/bjoc.13.34 Abstract New photoluminescent donor–acceptor–donor (DAD

• by quantum chemical DFT/TDDFT calculations carried out for these new molecules. Keywords: bithiophene; donor–acceptor; luminescence; 1,3,4-oxadiazole; palladium-catalyzed coupling; Introduction π-Conjugated donor–acceptor (D-A) compounds are of significant scientific interest because they

• field calls for elaboration of new synthetic procedures affording tailor-made molecules with tunable physical properties. In this respect, we have recently developed an efficient and flexible approach to the synthesis of π-conjugated donor–acceptor compounds [16][17]. The proposed synthetic pathway