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

• OLEDs could be obtained with easy modulation of the electroluminescent properties. Recently, the first examples of versatile exciplex-forming materials which can form two different types of exciplexes, donor–acceptor/donor and acceptor/donor–acceptor, were reported for simplified non-doped white OLEDs

• an electron acceptor in donor–acceptor systems [14]. The target compounds were obtained by nucleophilic substitution reaction of the intermediate quinazoline derivative Q1 with the corresponding donor compounds. The chemical structures were characterized by 1H NMR, 13C NMR, ATRIR spectroscopy and

Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

• Nuray Altinolcek,
• Ahmet Battal,
• Mustafa Tavasli,
• William J. Peveler,
• Holly A. Yu and
• Peter J. Skabara

Beilstein J. Org. Chem. 2020, 16, 1066–1074, doi:10.3762/bjoc.16.93

• homoleptic or heteroleptic iridium(III) complexes were also reported in the construction of different OLEDs [10][11][12][13]. In OPVs, carbazole derivatives are frequently used as small molecule p-type (electron-donating) materials or electron-accepting (n-type) materials with a variety of donor–acceptor

• transport properties with positive solvatochromism. Whilst 7a showed very low emission intensity, 7b showed very high emission intensity. It is noted that the conjugation in compound 7b encompasses the N atom of the carbazole ring and the formyl functionality (viz. the donor/acceptor units of the ICT

Bipyrrole boomerangs via Pd-mediated tandem cyclization–oxygenation. Controlling reaction selectivity and electronic properties

• Liliia Moshniaha,
• Marika Żyła-Karwowska,
• Joanna Cybińska,
• Piotr J. Chmielewski,
• Ludovic Favereau and
• Marcin Stępień

Beilstein J. Org. Chem. 2020, 16, 895–903, doi:10.3762/bjoc.16.81

• Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) UMR 6226, F-35000 Rennes, France 10.3762/bjoc.16.81 Abstract Boomerang-shaped bipyrroles containing donor–acceptor units were obtained through a tandem palladium-mediated reaction consisting of a cyclization step, involving double C–H bond

• measurements show that helicene-like boomerangs may be usable as circularly polarized luminescent materials. Keywords: donor–acceptor systems; double C–H bond activation; helicenes; pyrroles; Introduction Nanographenes and other polycyclic aromatics as well as their heterocyclic analogues are typically

• features characteristic of donor–acceptor systems (Supporting Information File 1, Figures S25–S30). For dilactams, cRnO, the HOMO orbital is primarily localized on the dilactam (bipyrrole) moiety, however, with some non-zero amplitudes on the NDA/NMI fragment, whereas the LUMO level encompasses the π

Photocatalytic deaminative benzylation and alkylation of tetrahydroisoquinolines with N-alkylpyrydinium salts

• David Schönbauer,
• Carlo Sambiagio,
• Timothy Noël and
• Michael Schnürch

Beilstein J. Org. Chem. 2020, 16, 809–817, doi:10.3762/bjoc.16.74

• , electrophilic alkyl radicals were used in several transformations, such as electrophilic cross couplings under nickel catalysis, either with boronic acids [35] or different (aryl)halides [36][37][38]. Furthermore, visible light-promoted uncatalyzed electron transfer via the formation of electron donor–acceptor

Towards triptycene functionalization and triptycene-linked porphyrin arrays

• Gemma M. Locke,
• Keith J. Flanagan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2020, 16, 763–777, doi:10.3762/bjoc.16.70

• candidates to study the potential electron donor–acceptor dyads [19]. Triptycene (1) consists of three benzene rings fused to a bicyclo[2.2.2]octane (BCO) skeleton, it is rigid, isolating and amenable to a wide range of chemical transformations. Due to the 120° rigid void, mono-, di-, tri-, tetra-, penta

Design and synthesis of diazine-based panobinostat analogues for HDAC8 inhibition

• Sivaraman Balasubramaniam,
• Sajith Vijayan,
• Liam V. Goldman,
• Xavier A. May,
• Kyra Dodson,
• Sweta Adhikari,
• Fatima Rivas,
• Davita L. Watkins and
• Shana V. Stoddard

Beilstein J. Org. Chem. 2020, 16, 628–637, doi:10.3762/bjoc.16.59

• prepared for docking using Sylbyl-X 2.1. A protocol defining the regions of hydrogen donor, acceptor and hydrophobic character was created using the SFXC protocol [41][42][43]. The Zn2+ ion which is known to be essential in the hydroxamate class of HDAC inhibitors was included in the preparation of the

Exploring the scope of DBU-promoted amidations of 7-methoxycarbonylpterin

• Anna R. Bockman and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2020, 16, 509–514, doi:10.3762/bjoc.16.46

• attractive scaffold in the field of supramolecular chemistry, due to their well-defined donor/acceptor hydrogen-bonding arrays [10][11]. One limitation often encountered with the synthesis of structurally diverse pterins is the notorious insolubility in most solvents. This can be dealt with by preemptive

Synthesis, liquid crystalline behaviour and structure–property relationships of 1,3-bis(5-substituted-1,3,4-oxadiazol-2-yl)benzenes

• Afef Mabrouki,
• Malek Fouzai,
• Armand Soldera,
• Abdelkader Kriaa and
• Ahmed Hedhli

Beilstein J. Org. Chem. 2020, 16, 149–158, doi:10.3762/bjoc.16.17

• hydrocarbon chain are mutually neutralized. In (CF2)m segment, Hasegawa et al. noted that the local dipoles Cδ+–Fδ− cannot be cancelled out and the surface of fluorocarbon chain remains polar [38]. Interaction rigid core-terminal chains The typical model for aromatic electron donor–acceptor (D–A) interactions

Reversible photoswitching of the DNA-binding properties of styrylquinolizinium derivatives through photochromic [2 + 2] cycloaddition and cycloreversion

• Sarah Kölsch,
• Heiko Ihmels,
• Jochen Mattay,
• Norbert Sewald and
• Brian O. Patrick

Beilstein J. Org. Chem. 2020, 16, 111–124, doi:10.3762/bjoc.16.13

• absorption and emission data revealed a significantly less pronounced donor–acceptor interplay in the methoxy-substituted derivatives 3b and 3c as compared to the strong donor–acceptor system 3a, as clearly indicated by the blue-shifted absorption and emission bands of 3b and 3c. Consequently, the absorption

• relative to the ones of the DNA base pairs [75][76]. Considering a dipole moment of the donor–acceptor systems 3a–c along the long molecular axis, a binding mode in which the ligand is accommodated in the intercalation site with its long molecular axis perpendicular to the long axis of the binding site

• concentration, i.e., at larger LDR, the ligands tended to form aggregates, as commonly observed for donor–acceptor dyes, that stacked along the grooves of DNA. Photocycloaddition reactions The photochemical properties of the derivatives 3a–d were investigated. Firstly, the substrates were irradiated in

Synthesis and optoelectronic properties of benzoquinone-based donor–acceptor compounds

• Daniel R. Sutherland,
• Nidhi Sharma,
• Georgina M. Rosair,
• Ifor D. W. Samuel,
• Ai-Lan Lee and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2019, 15, 2914–2921, doi:10.3762/bjoc.15.285

• compounds (Figure 1), with the aim of exploring their optoelectronic properties. Results and Discussion Synthesis We initiated our studies by synthesizing monofunctionalized donor–acceptor compounds 2–4, using the Pd(II)-catalyzed direct C–H functionalization method described below (Scheme 2). To our

• consistent with 3 having higher ΦPL than the other compounds. Conclusion Three novel monofunctionalized donor–acceptor BQ derivatives 2–4 were synthesized using an efficient Pd-catalyzed C–H functionalization method, and novel 2,5-difunctionalized BQ derivative 5 was also obtained via Suzuki coupling. The

• theoretical, electrochemical, and photophysical properties of the donor–acceptor compounds 2–5 were determined in solution and thin film. While compounds 2, 4, and 5 were very poorly emissive, 3 showed a green emission with a biexponential lifetime characterized by a prompt nanosecond component and a delayed

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

• , dimethylamino-substituted α-pyrones, as donor–acceptor systems, display remarkable photophysical properties, such as strongly red-shifted absorption and emission maxima with daylight fluorescence and fluorescence quantum yields up to 99% in solution and around 11% in the solid state, as well as pronounced

• , entry 6). The introduction of a more strongly electron-donating substituent, such as N,N-dimethylaminophenyl, causes a significant bathochromic shift (Table 8, entries 3 and 5). Donor–acceptor substitution in positions 4 and 6 causes a further bathochromic shift (Table 8, entry 7). In solution only N,N

• -dimethylaminophenyl-substituted derivatives fluoresce (Figure 10). While the 6-substituted α-pyrone 6c has a fluorescence maximum at 567 nm, the one for the regioisomer 6e is shifted bathochromically to 634 nm (Table 8, entries 3 and 5). Donor–acceptor substitution in positions 4 and 6 causes a further bathochromic

Probing of local polarity in poly(methyl methacrylate) with the charge transfer transition in Nile red

• Aydan Yadigarli,
• Qimeng Song,
• Sergey I. Druzhinin and
• Holger Schönherr

Beilstein J. Org. Chem. 2019, 15, 2552–2562, doi:10.3762/bjoc.15.248

• fluorescence (Figure 2a). This behavior for NR [35] is similar to donor–acceptor-substituted stilbenes [36][37], benzenes [38][39] and aminocoumarins [35][40][41]. This effect is caused by solvent relaxation around dipolar solutes that possess in the lowest excited state a substantially higher dipole moment

Reversible switching of arylazopyrazole within a metal–organic cage

• Anton I. Hanopolskyi,
• Soumen De,
• Michał J. Białek,
• Yael Diskin-Posner,
• Liat Avram,
• Moran Feller and
• Rafal Klajn

Beilstein J. Org. Chem. 2019, 15, 2398–2407, doi:10.3762/bjoc.15.232

• affected by their confinement to the surfaces of inorganic nanoparticles. Among other examples, the isomerization kinetics of azobenzene could be tuned by a factor of >5000 by the molecules with which it was co-adsorbed on gold nanoparticles [23], and donor–acceptor Stenhouse adduct (DASA) switches were

Cyclopropanation–ring expansion of 3-chloroindoles with α-halodiazoacetates: novel synthesis of 4-quinolone-3-carboxylic acid and norfloxacin

• Sara Peeters,
• Linn Neerbye Berntsen,
• Pål Rongved and
• Tore Bonge-Hansen

Beilstein J. Org. Chem. 2019, 15, 2156–2160, doi:10.3762/bjoc.15.212

• functionalization [3][4][5][6]. The metal carbene reactions with indoles have been studied for the three types of carbenoids: acceptor–acceptor [7][8][9], mono-acceptor [10] and donor–acceptor carbenoids [11][12][13][14]. Depending on the metal and the diazo compound, the chemo- and regioselectivity in the metal

1,2,3,4-Tetrahydro-1,4,5,8-tetraazaanthracene revisited: properties and structural evidence of aromaticity loss

• Arnault Heynderickx,
• Sébastien Nénon,
• Olivier Siri,
• Vladimir Lokshin and
• Vladimir Khodorkovsky

Beilstein J. Org. Chem. 2019, 15, 2059–2068, doi:10.3762/bjoc.15.203

• led to variation of its electron donor/acceptor capability that allowed fine-tuning the absorption properties. The propensity of these compounds and a number of its derivatives to form infinite chains involving >N–H···N= and >N–H···Hal−···N+ atoms is demonstrated by X-ray structure analysis. The DFT

Complexation of chiral amines by resorcin[4]arene sulfonic acids in polar media – circular dichroism and diffusion studies of chirality transfer and solvent dependence

• Bartosz Setner and
• Agnieszka Szumna

Beilstein J. Org. Chem. 2019, 15, 1913–1924, doi:10.3762/bjoc.15.187

• conclusion comes from a comparison of complexes in methanol and DMSO. One would expect that due to the dual hydrogen bond donor/acceptor character of methanol this solvent should be more destructive to ion-pair complexes based on charged hydrogen bonds than DMSO that can only serve as a hydrogen bond

Vicinal difunctionalization of alkenes by four-component radical cascade reaction of xanthogenates, alkenes, CO, and sulfonyl oxime ethers

• Shuhei Sumino,
• Takahide Fukuyama,
• Mika Sasano,
• Ilhyong Ryu,
• Antoine Jacquet,
• Frédéric Robert and
• Yannick Landais

Beilstein J. Org. Chem. 2019, 15, 1822–1828, doi:10.3762/bjoc.15.176

• a single operation [1][2][3][4][5]. Needless to say, the contribution by radical chemistry is not trivial [5][6][7]. While alkenes and alkynes have served as efficient radical donor/acceptor type C2 synthons in multicomponent radical reactions, CO and isonitriles were shown to react as donor

• /acceptor type C1 synthons [6][7][8][9][10][11][12][13][14][15]. In this context, sulfonyl oxime ethers are powerful acceptors of type C1 synthon [8][16][17], which terminates the multicomponent reaction by a β-scission of RSO2 radicals [18][19][20]. Recently, one of us reported on a three-component radical

Synthesis, photophysical and electrochemical properties of pyridine, pyrazine and triazine-based (D–π–)₂A fluorescent dyes

• Keiichi Imato,
• Toshiaki Enoki,
• Koji Uenaka and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2019, 15, 1712–1721, doi:10.3762/bjoc.15.167

• Keiichi Imato Toshiaki Enoki Koji Uenaka Yousuke Ooyama Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527, Japan 10.3762/bjoc.15.167 Abstract The donor–acceptor–π-conjugated (D–π–)2A fluorescent dyes OUY-2, OUK-2

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