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

• vibronic structure [7]. The ΔEST of 1 and 2 are 0.19 and 0.09 eV, respectively, indicating that compound 2 may have a much more efficient RISC process than 2 [19][20] (Table 3). To gain a further understanding of the photophysical properties of 1 and 2 in solid state, two doped films in 4,4’-dicarbazolyl

• solution. However, the PL spectrum of 2 is slightly blue-shifted from its PL spectrum in toluene, while 1:CBP shows alike spectra with 1 in toluene. It could be considered as the solid-state solvation effect [21], as 2 and 1 have different dipole moment of 1.814 D and 3.501 D, respectively from DFT

Enhanced quantum yields by sterically demanding aryl-substituted β-diketonate ancillary ligands

• Rebecca Pittkowski and
• Thomas Strassner

Beilstein J. Org. Chem. 2018, 14, 664–671, doi:10.3762/bjoc.14.54

• 3 by a solid-state structure (Figure 1). Details of the structure determination are given in Supporting Information File 1, Table S1. The absorption spectra (Figure 2) were measured in dichloromethane solution at ambient temperature. The complexes show almost identical absorption behavior with only

• ). Supporting Information The Supporting Information contains NMR-spectra, additional figures, details of the solid state structure determination and computational details. CCDC 1823322 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via http

• ://www.ccdc.cam.ac.uk/data_request/cif, or by emailing data_request@ccdc.cam.ac.uk, or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB21EZ, UK; fax: +44 1223 336033. Supporting Information File 67: NMR spectra, additional figures, details of the solid state structure determination

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

• behaviour was found even for T24 and T25 that have just been discussed above since mechanochromic properties were evidenced for the four emitters. Based on photophysical investigations, the presence of two different packing modes in the solid state were proven. When tested in OLEDs, no clear conclusions

Halogen-containing thiazole orange analogues – new fluorogenic DNA stains

• Aleksey A. Vasilev,
• Meglena I. Kandinska,
• Stanimir S. Stoyanov,
• Stanislava B. Yordanova,
• David Sucunza,
• Juan J. Vaquero,
• Obis D. Castaño,
• Stanislav Baluschev and
• Silvia E. Angelova

Beilstein J. Org. Chem. 2017, 13, 2902–2914, doi:10.3762/bjoc.13.283

• irradiation at 532 nm by 80 mW continuous wave frequency doubled DPSS (diode pumped solid state) laser, (Figures S21–S24, Supporting Information File 1). Computational studies Optimized structures of the preferred conformers of the cationic fragments of all dyes with the counterion I− (in the preffered

The photodecarboxylative addition of carboxylates to phthalimides as a key-step in the synthesis of biologically active 3-arylmethylene-2,3-dihydro-1H-isoindolin-1-ones

• Ommid Anamimoghadam,
• Saira Mumtaz,
• Anke Nietsch,
• Gaetano Saya,
• Cherie A. Motti,
• Jun Wang,
• Peter C. Junk,
• Ashfaq Mahmood Qureshi and
• Michael Oelgemöller

Beilstein J. Org. Chem. 2017, 13, 2833–2841, doi:10.3762/bjoc.13.275

• photoaddition products 3a and 3b were unambiguously confirmed by X-ray crystallography (Figure 2). In the solid state, molecules of both compounds undergo hydrogen bonding between the newly formed hydroxy group and the intact carbonyl group, resulting in a one-dimensional network (see Supporting Information

• -isomers was again observed (Table 4, entries 26 and 27). The solid state structure of the amination product (Z)-8a was furthermore established by X-ray crystal structure analysis (Figure 4). The phenyl group of the arylmethylene unit is positioned almost perpendicular to the isoindolinone ring on top of

Pyrene–nucleobase conjugates: synthesis, oligonucleotide binding and confocal bioimaging studies

• Artur Jabłoński,
• Yannic Fritz,
• Hans-Achim Wagenknecht,
• Rafał Czerwieniec,
• Tytus Bernaś,
• Damian Trzybiński,
• Krzysztof Woźniak and
• Konrad Kowalski

Beilstein J. Org. Chem. 2017, 13, 2521–2534, doi:10.3762/bjoc.13.249

• /C17/C18/O26 atoms and non-hydrogen atoms of the pyrenyl group are inclined by an angle of 17.26(5)°. The carbonyl oxygen atom O26 is involved in the intramolecular hydrogen bond with the hydrogen atom H3 of the pyrenyl group. The C3–H3···O26 hydrogen bond length is 2.879(2) Å. In the solid state, each

• synthesis of 2 and 3 A mixture of 3-chloropropionylpyrene (293 mg, 1.0 mmol) and Et3N (278 μL) in DMF (20 mL) was vigorously stirred at room temperature for 20 min. Then, the appropriate nucleobase (1 equiv) was added (in a solid state) and the mixture was stirred at a temperature of 75 °C for 5 h

Exploring mechanochemistry to turn organic bio-relevant molecules into metal-organic frameworks: a short review

• Vânia André,
• Sílvia Quaresma,
• João Luís Ferreira da Silva and
• M. Teresa Duarte

Beilstein J. Org. Chem. 2017, 13, 2416–2427, doi:10.3762/bjoc.13.239

• promoting solid-state reactions [8][9][10][11]. Polymer-assisted grinding (POLAG) is another variation of mechanochemistry, very recently disclosed and making use of polymers to stimulate the reaction [6][12]. Concerning the synthesis of molecular compounds and molecular crystals [2][13][14][15

Synthesis, effect of substituents on the regiochemistry and equilibrium studies of tetrazolo[1,5-a]pyrimidine/2-azidopyrimidines

• Elisandra Scapin,
• Paulo R. S. Salbego,
• Caroline R. Bender,
• Alexandre R. Meyer,
• Anderson B. Pagliari,
• Tainára Orlando,
• Geórgia C. Zimmer,
• Clarissa P. Frizzo,
• Helio G. Bonacorso,
• Nilo Zanatta and
• Marcos A. P. Martins

Beilstein J. Org. Chem. 2017, 13, 2396–2407, doi:10.3762/bjoc.13.237

• (R in the 4-position of the ring), which was attributed to an equilibrium of azide–tetrazole. In the solid state, all compounds were found as 2-azidopyrimidines. The regiochemistry of the reaction and the stability of the products are discussed on the basis of the data obtained by density functional

• nature of the substituents, solvent, temperature, and physical state of the compound (solid state or solution) are the properties that have the most influence on the azide–tetrazole equilibrium [20][21][22][23][24][25][26][27][28]. A comprehensive understanding of the azide–tetrazole equilibrium is of

• substituent of the tetrazolo[1,5-a]pyrimidines and/or the solvent used to dissolve the compounds. The equilibrium of tetrazolo[1,5-a]pyrimidine and 2-azidopyrimidine in the solid state Furthermore, as observed in the literature, in the solid state or in DMSO-d6, the tetrazolo[1,5-a]pyrimidines are favored or

Structure–property relationships and third-order nonlinearities in diketopyrrolopyrrole based D–π–A–π–D molecules

• Jan Podlesný,
• Lenka Dokládalová,
• Oldřich Pytela,
• Adam Urbanec,
• Milan Klikar,
• Numan Almonasy,
• Tomáš Mikysek,
• Jaroslav Jedryka,
• Iwan V. Kityk and
• Filip Bureš

Beilstein J. Org. Chem. 2017, 13, 2374–2384, doi:10.3762/bjoc.13.235

• chromatography without a need of further crystallization. Hence, this ferrocene derivative was prepared with the highest yield of 73%. In the solid state, all target chromophores resemble dark metallic solids. Differential scanning calorimetry The thermal behaviour of compounds 1–5b was studied by differential

Solvent-free copper-catalyzed click chemistry for the synthesis of N-heterocyclic hybrids based on quinoline and 1,2,3-triazole

• Martina Tireli,
• Silvija Maračić,
• Stipe Lukin,
• Marina Juribašić Kulcsár,
• Dijana Žilić,
• Mario Cetina,
• Ivan Halasz,
• Silvana Raić-Malić and
• Krunoslav Užarević

Beilstein J. Org. Chem. 2017, 13, 2352–2363, doi:10.3762/bjoc.13.232

• reactions, with up to a 15-fold gain in yield. Efficiency of both solution and milling procedures depended on the p-substituent in the azide reactant, resulting in H < Cl < Br < I reactivity bias. Solid-state catalysis using Cu(II) and Cu(I) catalysts entailed the direct involvement of the copper species in

• spin resonance (ESR) spectroscopy; in situ Raman monitoring; mechanochemistry; quinoline; solid-state click chemistry; Introduction The copper-catalyzed azide–alkyne cycloaddition (CuAAC) represents a prime example of click chemistry. Click chemistry describes “a set of near-perfect” reactions [1] for

• the organic solid-state synthesis, revealing the base-catalysis in an amide formation reaction [48], and detecting intermediate phases not available from solution [49]. Raman spectra (Figure 1) were assigned combining literature data [50] and DFT calculations. Calculated spectra are shown in Figures

One-pot syntheses of blue-luminescent 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones by T3P^® activation of 3-arylpropiolic acids

• Melanie Denißen,
• Alexander Kraus,
• Guido J. Reiss and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2017, 13, 2340–2351, doi:10.3762/bjoc.13.231

• character, as supported by the influence of the remote polar substitution (Figure 7). Interestingly, compound 4a, which has a fluorescence quantum yield Φf of less than 0.01 in dichloromethane solution, experiences an over eightfold increase to 0.08 in the solid state emission as determined from the powder

Structural diversity in the host–guest complexes of the antifolate pemetrexed with native cyclodextrins: gas phase, solution and solid state studies

• Magdalena Ceborska,
• Magdalena Zimnicka,
• Aneta Aniela Kowalska,
• Kajetan Dąbrowa and
• Barbara Repeć

Beilstein J. Org. Chem. 2017, 13, 2252–2263, doi:10.3762/bjoc.13.222

• gas phase, in solution and in the solid state. Mass spectrometry was employed for the investigation of the architecture and relative gas-phase stabilities of these supramolecular complexes. The mode of complexation was further tracked by 1D and 2D NMR proving the formation of the exclusion-type

• equivalent – methyl α-D-glucopyranoside – was investigated for a deeper understanding of the type of host–guest interactions. Solid state studies of PTX/CDs were performed using FTIR–ATR and Raman spectroscopy techniques. Keywords: antifolate; cyclodextrin; hydrophobic interactions; inclusion complexes

• ; pemetrexed; supramolecular chemistry; Introduction Herein, supramolecular host–guest complexes of the potent folic acid inhibitor pemetrexed (PTX, Figure 1a) with native cyclodextrins (α-, β- and γ-CDs, Figure 1b) in the gas phase (MS), in solution (NMR, UV–vis) and in the solid state (Raman, FTIR–ATR) were

Phosphonic acid: preparation and applications

• Charlotte M. Sevrain,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2017, 13, 2186–2213, doi:10.3762/bjoc.13.219

• relevant methods that can be employed to produce phosphonic acids. 2. Phosphonic acids: properties and applications In the solid state, a phosphonic acid function possesses one P–O bond which is shorter than the two others and that can be attributed to the P=O double bond (as an example for

• with triphenylphosphine functionalized either by two or three phosphonic acid sodium salts; the former being more water soluble than the later [24]. This behavior is associated to the fact that the trisphosphonic acid sodium salt was already solvated at the solid state. The high polarity of the

The effect of milling frequency on a mechanochemical organic reaction monitored by in situ Raman spectroscopy

• Patrick A. Julien,
• Ivani Malvestiti and
• Tomislav Friščić

Beilstein J. Org. Chem. 2017, 13, 2160–2168, doi:10.3762/bjoc.13.216

• room temperature (benzil: 94–96 °C; o-phenylenediamine: 100–102 °C; 2,3-diphenylquinoxaline: 125–127 °C) and no melting was observed upon grinding together of the two reactants, the formation of 2,3-diphenylquinoxaline is a good example of a solid-state reaction. Moreover, XRPD analysis of the crude

• Bruker Vertex 70 FT-IR Platinum ATR, while X-ray powder diffraction patterns were collected on a Proto Manufacturing AXRD Benchtop Powder Diffractometer using Ni-filtered Cu Kα radiation. The conversion for each solid-state reaction was evaluated after milling using 1H NMR spectroscopy conducted in CDCl3

Solid-state studies and antioxidant properties of the γ-cyclodextrin·fisetin inclusion compound

• Joana M. Pais,
• Maria João Barroca,
• Maria Paula M. Marques,
• Filipe A. Almeida Paz and
• Susana S. Braga

Beilstein J. Org. Chem. 2017, 13, 2138–2145, doi:10.3762/bjoc.13.212

• compound is evaluated by the DPPH assay. Keywords: antioxidant activity; co-lyophilization; fisetin; gamma-cyclodextrin; molecular encapsulation; solid-state analysis; Introduction Flavonoids, natural compounds with numerous beneficial actions on human health, including antioxidant [1], anti-inflammatory

• using solid-state techniques was carried out to confirm fisetin inclusion into the cavity of γ-CD, and to present the hypothetical structural arrangement of the host–guest units. Further, the retention of the antioxidant activity in the inclusion compound was evaluated by its ability to scavenge the

• radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). Results and Discussion The present report is divided into two main parts, the first one being the preparation of the inclusion compound of fisetin with γ-CD and its characterization by a collection of solid-state techniques. The second part comprises the

Novel approach to hydroxy-group-containing porous organic polymers from bisphenol A

• Tao Wang,
• Yan-Chao Zhao,
• Li-Min Zhang,
• Yi Cui,
• Chang-Shan Zhang and
• Bao-Hang Han

Beilstein J. Org. Chem. 2017, 13, 2131–2137, doi:10.3762/bjoc.13.211

• . Fourier transform infrared and solid-state 13C CP/MAS NMR spectroscopy are utilized to characterize the possible structure of the obtained polymers. The highest Brunauer–Emmet–Teller specific surface area of the phenolic-resin porous organic polymers (PPOPs) is estimated to be 920 m2 g–1. The PPOPs

• assigned to the stretching vibration of carbonyl groups is significantly reduced in PPOPs, indicating that most of the aldehyde compounds are consumed. Solid-state 13C CP/MAS NMR spectroscopy was employed to characterize the structure of the polymers PPOPs. As shown in Figure 2 and Figure S4 (Supporting

• . FTIR spectra of terephthalic aldehyde (M1), BPA, and PPOP-1. Solid-state 13C CP/MAS NMR spectrum of PPOP-1 recorded at the MAS rate of 5 kHz. (a) Nitrogen adsorption–desorption isotherms of PPOP-1 (downtriangle), PPOP-2 (circle), and PPOP-3 (square) at 77 K. The isotherms have been offset by 100 cm3 g

Main group mechanochemistry

• Agota A. Gečiauskaitė and
• Felipe García

Beilstein J. Org. Chem. 2017, 13, 2068–2077, doi:10.3762/bjoc.13.204

• group compounds and frameworks. Keywords: ball milling; main group; mechanochemical synthesis; mechanochemistry; Introduction The original mainspring for the current expansion of solid state methodologies is the need for cleaner, safer and sustainable chemical transformations – particularly since raw

• materials are becoming ever scarcer. A straightforward strategy to addressing the above is to simply remove or minimise solvent usage throughout any designated synthetic routes. One way to achieve a solvent-free, or nearly solvent-free, synthetic route is via the use of solid-state mechanochemical

• methodologies. Mechanochemistry [1][2][3][4][5][6][7][8][9][10] is an emerging solid state methodology involving the use of little or no solvent, with the potential to challenge the current dominance of ‘wet’ chemical synthesis [11][12][13][14][15]. From a purely synthetic point of view, it is clear that

Complexation of molecular clips containing fragments of diphenylglycoluril and benzocrown ethers with paraquat and its derivatives

• Leonid S. Kikot',
• Catherine Yu. Kulygina,
• Alexander Yu. Lyapunov,
• Svetlana V. Shishkina,
• Roman I. Zubatyuk,
• Tatiana Yu. Bogaschenko and
• Tatiana I. Kirichenko

Beilstein J. Org. Chem. 2017, 13, 2056–2067, doi:10.3762/bjoc.13.203

• , Kharkiv, Ukraine 10.3762/bjoc.13.203 Abstract The complexation of molecular clips containing fragments of diphenylglycoluril and benzocrown ethers with paraquat and its derivatives has been studied both in solution and in the solid state. In this paper we studied the influence of the crown ether ring

• the nitrogen atoms of paraquat usually increases the stability of complexes formed, which is caused by their additional stabilization due to hydrogen bonds between the terminal hydroxy groups and oxygen atoms of the polyether chains, and the carbonyl groups of the molecular clips. In the solid state

Are boat transition states likely to occur in Cope rearrangements? A DFT study of the biogenesis of germacranes

• José Enrique Barquera-Lozada and
• Gabriel Cuevas

Beilstein J. Org. Chem. 2017, 13, 1969–1976, doi:10.3762/bjoc.13.192

• molecule or an actual water molecule could participate as donor and acceptor of the germacranolide proton. In fact, in the solid state 1 cocrystalizes with a water molecule [72]. The next step in this mechanism is the Cope rearrangement which have a TS (TS5-3) less energetic than the Cope TS without

Solid-state mechanochemical ω-functionalization of poly(ethylene glycol)

• Michael Y. Malca,
• Pierre-Olivier Ferko,
• Tomislav Friščić and
• Audrey Moores

Beilstein J. Org. Chem. 2017, 13, 1963–1968, doi:10.3762/bjoc.13.191

• PEG with tosyl, bromide, thiol, carboxylic acid or amine functionalities in good to quantitative yields and with no polymer chain oligomerization, proving the versatility of the method. Keywords: amination; bromination; carboxylation; mechanochemistry; poly(ethylene glycol); solid state; thiolation

• of pharmaceutical industry for the development of cleaner, more efficient synthetic techniques [22], we now explore the possibility of accessing PEG derivatives in the solid-state. The use of mechanochemistry to achieve both supramolecular [23] and covalent [24] synthesis and modification of active

One-pot multistep mechanochemical synthesis of fluorinated pyrazolones

• Joseph L. Howard,
• William Nicholson,
• Yerbol Sagatov and
• Duncan L. Browne

Beilstein J. Org. Chem. 2017, 13, 1950–1956, doi:10.3762/bjoc.13.189

• ; mechanochemistry; multistep; solid-state synthesis; Introduction Mechanochemical methods are emerging as an alternative approach to traditional solvent-based reactions for chemical synthesis. Under mechanochemical conditions reactions are performed between neat reagents and do not require a solvent. Processing

• (Table 1, entry 12), where the yield dropped. The latter observation may be due to the larger amount of liquid altering the texture of the reaction mixture and thus reducing effective mixing. An alternative justification is that at higher acid equivalents in the solid state the ‘on–off’ protonation of

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• in the absence of solvent’ and that was a common belief till last few decades. However, during the 1980s the pioneering works of Toda and co-workers proved that many organic reactions of solution chemistry would be reproducible in solid state too [22][23]. In the solid state reactions the ingredients

• significant in organic synthesis because aryl halides are important synthons for the synthesis of many natural and non-natural products [93][94]. In 2005, Rahman and co-workers reported a pioneering solid state benzylic bromination of diquinoline derivatives via N-bromosuccinimide (NBS) [95]. In 2012, Wang

• synthesis as well as in inorganic coordination chemistry [172]. However, the mechanochemical organometallic synthesis is still in its infancy due to certain difficulties under solvent-free synthesis. Recently the solid state syntheses of organometallic compounds have become popular. In their pioneering work

Solvent-free sonochemistry: Sonochemical organic synthesis in the absence of a liquid medium

• Deborah E. Crawford

Beilstein J. Org. Chem. 2017, 13, 1850–1856, doi:10.3762/bjoc.13.179

• ultrasonic irradiation at room temperature that is instigating and accelerating this chemical reaction. Further confirmation that sonochemistry is a viable method to carry out solid state organic synthesis was obtained by carrying out an aldol reaction between ninhydrin and dimedone (Scheme 2). The optimised

• reactions was the particle size of the starting materials, with a reduced particle size of <200 µm resulting in a homogeneous mixture leading to complete conversion to the product. This provides an excellent foundation for further investigations into solvent-free or solid-state sonochemistry, including

Mechanochemical synthesis of thioureas, ureas and guanidines

• Vjekoslav Štrukil

Beilstein J. Org. Chem. 2017, 13, 1828–1849, doi:10.3762/bjoc.13.178

• Vjekoslav Strukil Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia 10.3762/bjoc.13.178 Abstract In this review, the recent progress in the synthesis of ureas, thioureas and guanidines by solid-state mechanochemical ball milling is

• , mechanochemistry has been demonstrated as an effective tool in reaction discovery, with emphasis on the reactivity differences in solution and in the solid state. These three classes of organic compounds share some structural features which are reflected in their physical and chemical properties, important for

• application as organocatalysts and sensors. On the other hand, the specific and unique nature of each of these functionalities render (thio)ureas and guanidines as the key constituents of pharmaceuticals and other biologically active compounds. Keywords: guanidines; mechanochemistry; solid state synthesis

Mechanochemical N-alkylation of imides

• Anamarija Briš,
• Mateja Đud and
• Davor Margetić

Beilstein J. Org. Chem. 2017, 13, 1745–1752, doi:10.3762/bjoc.13.169

• employed. By conducting the reaction in a ball mill, solubility problems and the issues associated with the selection of the most suitable solvent could be avoided. In addition, solid-state reaction diminishes the heterogeneous character of alkylation, since inorganic bases in general are not soluble in

• reaction proceeds in a similar manner and yield to the condensation reaction carried out under classical reaction conditions (1 M HCl, 60 °C, 30 min) [38]. Mechanochemical one-pot, two-step solid-state N-alkylation of 36 with benzyl bromide yielded 1,3-dibenzylalloxazine 39 in quantitative yield, whereas