Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

Light-responsive rotaxane-based materials: inducing motion in the solid state

• Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

• Adrian Saura-Sanmartin Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, 30100 Murcia, Spain 10.3762/bjoc.19.64 Abstract Light-responsive rotaxane-based solid-state materials are ideal scaffolds in order to develop smart materials due to the properties provided by the

• is the functionalization of mesoporous silica nanoparticles with light-responsive rotaxane-based molecular shuttles to control the uptake and release of target molecules [31][32][33][34]. This perspective is focused on recent examples of light-responsive rotaxane-based solid-state materials in which

• analyze selected recent examples, a critical opinion on the state of the art is provided, including some future directions of this research field and postulating light-responsive solid-state rotaxane materials as tailorable scaffolds which will be used in a wide range of advanced applications. Discussion

Construction of hexabenzocoronene-based chiral nanographenes

• Ranran Li,
• Di Wang,
• Shengtao Li and
• Peng An

Beilstein J. Org. Chem. 2023, 19, 736–751, doi:10.3762/bjoc.19.54

• of 91 was significantly improved. The enantiomers of 91 were proved as NIR-CPL emitters with 600 to 800 nm range of emission and glum values of 3 × 10−3 both in solution and in the solid state. Multilayer (e.g., bilayer and trilayer) graphenes that are composed of stacked graphenic layers exhibit

pH-Responsive fluorescent supramolecular nanoparticles based on tetraphenylethylene-labelled chitosan and a six-fold carboxylated tribenzotriquinacene

• Nan Yang,
• Yi-Yan Zhu,
• Wei-Xiu Lin,
• Yi-Long Lu and
• Wen-Rong Xu

Beilstein J. Org. Chem. 2023, 19, 635–645, doi:10.3762/bjoc.19.45

• reaction to generate the corresponding multiple Schiff bases and then reduced with sodium borohydride (Scheme 1a). The structure of CS-TPE was characterized by 1H NMR spectra and solid-state CP/MAS 13C NMR spectra, and the results were found to agree with the proposed structure. For instance, the products

• 20 mol % was calculated to be 1.6, 3.2 and 6.6 mol %, respectively, increasing as Rf increased. Fluorescent properties of CS-TPE in the solid state. CS-TPE bioconjugates were found to be AIE active, like other TPE-modified derivatives in previous works [25][26]. As shown in Figure 2a, the solid

• illumination in the solid state due to powerful self-quenching effects in the aggregates [25]. Strong emission is observed at approximately 485 nm for all CS-TPE bioconjugates in the solid state (Figure 2b). A major reason for the emission behavior is the restriction in intramolecular rotation (RIR) of

Phenanthridine–pyrene conjugates as fluorescent probes for DNA/RNA and an inactive mutant of dipeptidyl peptidase enzyme

• Josipa Matić,
• Tana Tandarić,
• Marijana Radić Stojković,
• Filip Šupljika,
• Zrinka Karačić,
• Ana Tomašić Paić,
• Lucija Horvat,
• Robert Vianello and
• Lidija-Marija Tumir

Beilstein J. Org. Chem. 2023, 19, 550–565, doi:10.3762/bjoc.19.40

• applications [9]. These compounds have a very large aromatic surface suitable to form self-assembled supramolecular structures by intermolecular π–π interactions and showed excimer fluorescence in thin film and in the solid state. Kawai et al. reported exciplex formation between pyrene and guanine in polar

Mechanochemical solid state synthesis of copper(I)/NHC complexes with K₃PO₄

• Ina Remy-Speckmann,
• Birte M. Zimmermann,
• Mahadeb Gorai,
• Martin Lerch and
• Johannes F. Teichert

Beilstein J. Org. Chem. 2023, 19, 440–447, doi:10.3762/bjoc.19.34

• complexes: Synthesis of bifunctional catalyst 5 via transmetallation. Mes = mesityl [48][49]. Application of bifunctional catalyst 5 in copper(I)-catalyzed hydrogenations: comparison of 5 prepared by solid state/ball milling (5bm) and liquid state (5ls) synthesis. Standard conditions: Substrate (0.40 mmol

• ), 10 mol % 5, 1.1 equiv NaOt-Bu, 1.3 equiv 15-crown-5, 100 bar H2, 1,4-dioxane (3 mL), 70 °C, 24 h. Attempted direct synthesis of bifunctional catalyst 5 from imidazolinium salt 3: liquid and solid state approaches. Synthesis of standard Cu(I)/NHC-complexes using K3PO4 as a weak base (standard

Preparation of β-cyclodextrin/polysaccharide foams using saponin

• Max Petitjean and
• José Ramón Isasi

Beilstein J. Org. Chem. 2023, 19, 78–88, doi:10.3762/bjoc.19.7

• , certainly because of a higher homogenization of the pre-crosslinked matrix. When prepared in powder (solid-state) form (45spPow), adding saponin will decrease the percent yield from 70% to 50%. Interestingly, the yield is not affected in that way when adding saponin into the liquid mixture (45spLiq

• or in the solid state, as shown in Figure 8. Thus, the solid mixtures were homogenized using a mortar as in previous works [38][39], and crosslinked at 170 °C during 20 or 45 min (samples 20Pow and 45Pow). A solid-state mixture with the addition of 0.5 g of saponin and a thermal crosslinking at 170

Improving the accuracy of ³¹P NMR chemical shift calculations by use of scaling methods

• William H. Hersh and
• Tsz-Yeung Chan

Beilstein J. Org. Chem. 2023, 19, 36–56, doi:10.3762/bjoc.19.4

• compounds when using the M06-2X optimization and the M06-L/GIAO NMR calculation (Table 4, entry 14). Interestingly, this functional was not recommended in a recent study on calculation of solid-state chemical shifts for 31P NMR [103]. Use of the CSGT NMR method gave a higher MAD (Table 4, entry 15) and M06

Inclusion complexes of the steroid hormones 17β-estradiol and progesterone with β- and γ-cyclodextrin hosts: syntheses, X-ray structures, thermal analyses and API solubility enhancements

• Alexios I. Vicatos,
• Zakiena Hoossen and
• Mino R. Caira

Beilstein J. Org. Chem. 2022, 18, 1749–1762, doi:10.3762/bjoc.18.184

• , which is a distinct disadvantage for solid-state structural investigation and complex characterization by X-ray diffraction methods. Results and Discussion Complex screening The isolation of solid inclusion complexes of BES and PRO with the native cyclodextrins β-CD and γ-CD was successfully achieved by

Inline purification in continuous flow synthesis – opportunities and challenges

• Jorge García-Lacuna and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 1720–1740, doi:10.3762/bjoc.18.182

• purification via a catch and release strategy [96]. Additionally, functionalized residues can be used to perform a solid-state synthesis approach, such as in the synthesis of 2-aminopyridine derivatives starting from amino-iminium residues [97]. To improve on this technology, Baxendale and co-workers utilized

Comparison of crystal structure and DFT calculations of triferrocenyl trithiophosphite’s conformance

• Ruslan P. Shekurov,
• Mikhail N. Khrizanforov,
• Ilya A. Bezkishko,
• Tatiana P. Gerasimova,
• Almaz A. Zagidullin,
• Daut R. Islamov and
• Vasili A. Miluykov

Beilstein J. Org. Chem. 2022, 18, 1499–1504, doi:10.3762/bjoc.18.157

• °, respectively, has been observed, although a propeller-like gauche-gauche-gauche configuration of alkyl(aryl)thio groups has been observed for trithiophosphites even in the solid state [7] or in the gas phase [8][9][10]. Triferrocenyl trithiophosphite has nine axes of internal rotation: three P–S bonds, three C

• ···π-bonded dimers (Figures S4 and S5 in Supporting Information File 1). The computations of the relative energies of five possible conformers of (PhS)3P (ggg, ttt, ttg, ggt, ccg) predict the lowest energy for the ccg conformation (Figure 5). The propeller-like ggg conformer found in the solid state

• optimized ttg conformer (left) and for two neighboring molecules (right) from X-ray analysis data. Molecular structures in the solid state of a) (FcS)3P, b) (FcS)3PO [19], and c) (FcS)3PS [7] as established by single crystal X-ray diffraction analyses. C atoms – grey, Fe atoms – brown, O atoms – red, P

Dissecting Mechanochemistry III

• Lars Borchardt and
• José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1454–1456, doi:10.3762/bjoc.18.150

• halides as substrates in multiple reactions. For instance, within this Thematic Issue, the synthetic relevance of aryl halides was evidenced during the development of a protocol for the solid-state palladium-catalyzed borylation reported by Kubota, Ito, and co-workers (Scheme 2) [6]. Moreover, Štrbac and

Synthesis of C6-modified mannose 1-phosphates and evaluation of derived sugar nucleotides against GDP-mannose dehydrogenase

• Sanaz Ahmadipour,
• Alice J. C. Wahart,
• Jonathan P. Dolan,
• Laura Beswick,
• Chris S. Hawes,
• Robert A. Field and
• Gavin J. Miller

Beilstein J. Org. Chem. 2022, 18, 1379–1384, doi:10.3762/bjoc.18.142

• minimum volume of hot EtOH, enabling solid state analysis (Figure 2). Crystals of 16 were analysed by single crystal X-ray diffraction and the data were solved in the monoclinic space group P21. Although the crystals suffered from intrinsic non-merohedral twinning through a non-crystallographic rotation

• , the structural model allowed unambiguous assignment of the solid state molecular structure and absolute configuration. As shown in Figure 2, the desired axial anomeric phosphate was clearly visible alongside an interesting gg rotameric form for the C6–chloro side chain substituent (pyranose side chain

Cyclodextrin-based Schiff base pro-fragrances: Synthesis and release studies

• Attila Palágyi,
• Jindřich Jindřich,
• Juraj Dian and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2022, 18, 1346–1354, doi:10.3762/bjoc.18.140

• benzaldehyde) and static headspace-gas chromatography (for benzaldehyde, heptanal, and 5-methylfurfural). The aldehyde release rate from the imine was shown to depend substantially on the pH from the solution and the air humidity from the solid state. Keywords: aldehyde; controlled release; cyclodextrin

• the release of flavor in solution or solid state [29][30][31]. The aldehyde release was studied using three different sampling time intervals corresponding to three time regions I, II, and III, in Figures 5–7. This experiment mode enabled better observation of the trends in the change of the aldehyde

• the system. Sustained release of the aldehyde was demonstrated both in aqueous solutions and from a solid state upon humidity exposure. Experimental Instruments, general methods, and chemicals 1H NMR, 13C NMR, 2D NMR (H,H-COSY, HSQC, and HMBC) were measured on Bruker AVANCE III 600 MHz (600.17 MHz for

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

• suggests that the conformation of the emitter in the solid state is slightly more conjugated than that in solution or that there are specific host–guest interactions with the DPA unit that perturbs the energy of the excited state. The emission is broader than that of a structurally similar emitter, QAD

Polymer and small molecule mechanochemistry: closer than ever

• José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1225–1235, doi:10.3762/bjoc.18.128

• solution and when ball milled in the solid state [29]. The results for bottlebrush polymers demonstrated a more pronounced arm scission by ball milling than by sonication, compared to the extent of backbone rupture. However, for dendronized polymers, arm scission could be accomplished by ball milling but

• between ball milling and ultrasonication were associated with the more restricted chain mobility in the solid state and with the dissimilar distribution of mechanical forces on the backbone and arms. With ball milling, these were more pronounced towards the arms of the polymer [29]. Other studies have

• to generate radicals (Scheme 3) [67]. The difference in the C–C bond scission between 6 and 8 was explained based on the ability of diarylurea moieties in 8 to form strong self-assemblies through hydrogen bonding. In the solid state, this enabled the transduction of mechanical force to the

From amines to (form)amides: a simple and successful mechanochemical approach

• Federico Casti,
• Rita Mocci and
• Andrea Porcheddu

Beilstein J. Org. Chem. 2022, 18, 1210–1216, doi:10.3762/bjoc.18.126

• ]. In general, mechanochemistry refers to studying solid-state chemical changes promoted by external mechanical energy, such as grinding or milling. A deeper understanding of its mechanistic aspects laid the basis for further growth in this topic, opening new routes to more efficient mechanochemical

Mechanochemical bottom-up synthesis of phosphorus-linked, heptazine-based carbon nitrides using sodium phosphide

• Blaine G. Fiss,
• Georgia Douglas,
• Michael Ferguson,
• Jorge Becerra,
• Jesus Valdez,
• Trong-On Do,
• Tomislav Friščić and
• Audrey Moores

Beilstein J. Org. Chem. 2022, 18, 1203–1209, doi:10.3762/bjoc.18.125

• at 300 °C for 1 hour under argon, the phosphorus content is shown to increase, while still remaining partially localized, with the particles retaining their size and morphology (Supporting Information File 1, Figure S4b). 31P magic angle spinning (MAS) NMR Bulk solid-state analysis of the heptazine

Derivatives of benzo-1,4-thiazine-3-carboxylic acid and the corresponding amino acid conjugates

• Péter Kisszékelyi,
• Tibor Peňaška,
• Klára Stankovianska,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2022, 18, 1195–1202, doi:10.3762/bjoc.18.124

• . The use of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in 1,4-dioxane afforded the dimer 11a in a slightly better yield of 46% (Scheme 2). For all the prepared benzothiazine derivatives 10 we observed some degree of instability. The derivatives were reasonably stable in the solid state but usually

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

• as well as the relevance for fluorescence-based acid–base sensing. Keywords: intramolecular charge transfer; molecular aggregates; sensing; thermally activated delayed fluorescence (TADF); Introduction Metal-free organic solid-state emitters have gained increasing interest in recent years due to

• 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

• solution and in the solid state and with multicolor tunability by external stimuli are crucial for task-specific applications. Recently, donor–acceptor (D–A)-based organic emitters have shown tunable optical and electrochemical properties due to alteration of the intermolecular charge-transfer (ICT

Synthesis, optical and electrochemical properties of (D–π)₂-type and (D–π)₂Ph-type fluorescent dyes

• Kosuke Takemura,
• Kazuki Ohira,
• Taiki Higashino,
• Keiichi Imato and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2022, 18, 1047–1054, doi:10.3762/bjoc.18.106

• and fluorescence maximum wavelengths (λmax,abs and λmax,fl) of OTT-2 appear in a longer wavelength region than those of OTK-2. The fluorescence quantum yield (Φfl) of OTT-2 is 0.41, which is higher than that (Φfl = 0.36) of OTK-2. In the solid state OTT-2 shows relatively intense fluorescence

• band, but also intense fluorescence emission both in solution and the solid state. Keywords: (D–π)2 structure; fluorescence; fluorescent dyes; photoabsorption; redox properties; Introduction The design and development of a new type of organic fluorescent dyes have been of considerable scientific and

• the higher Φfl value of OTT-2 is mainly attributed to the smaller knr value compared with that of OTK-2. The solid-state optical properties of OTK-2 and OTT-2 were investigated by solid-state UV–vis diffuse reflection–photoabsorption and fluorescence spectral measurements, and time-resolved

Automated grindstone chemistry: a simple and facile way for PEG-assisted stoichiometry-controlled halogenation of phenols and anilines using N-halosuccinimides

• Dharmendra Das,
• Akhil A. Bhosle,
• Amrita Chatterjee and
• Mainak Banerjee

Beilstein J. Org. Chem. 2022, 18, 999–1008, doi:10.3762/bjoc.18.100

• selected as the LAG agent keeping all other parameters the same. Interestingly, the monobrominated product 2a was obtained almost exclusively in an excellent yield (91%) within just 5 min of grinding (Table 1, entry 6). The attempted model reaction under solid-state grinding using silica gel was sluggish

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

• -conjugated ring structures [15]. In the solid state, fused systems are prone to form highly ordered π–π-stacked structures [16], leading to better bulk charge transport [17]. Another important aspect is solubility, which is generally poor in larger conjugated molecules [3]. This is even aggravated for fused

• further functionalised with (triisopropylsilyl)ethynyl [24] (6) or with 1,3-dithiole units [25] (7) by other research groups. The (triisopropylsilyl)ethynyl (TIPSE) groups are introduced to improve the solubility and solid-state order, fostering intermolecular π-orbital interactions [26]. Moreover

• spectra of EtH-T-DI-DTT were measured in dichloromethane in 10−5 mol L−1 solutions. For solid-state measurements, EtH-T-DI-DTT was spin-coated from a chloroform solution on a quartz wafer. Both solution and solid-state spectra (Figure 8) show a main band at ca. 350 nm, which is due to a localised π–π

On Reuben G. Jones synthesis of 2-hydroxypyrazines

• Pierre Legrand and
• Yves L. Janin

Beilstein J. Org. Chem. 2022, 18, 935–943, doi:10.3762/bjoc.18.93

• bond thus confirming an oxo-bearing tautomeric form adopted in the solid state. Concerning the mechanism of this double condensation, the interpretation of the experimental results must take into account two very likely side reactions. The first one would be a Cannizzaro reaction which, from the

Palladium-catalyzed solid-state borylation of aryl halides using mechanochemistry

• Koji Kubota,
• Emiru Baba,
• Tamae Seo,
• Tatsuo Ishiyama and
• Hajime Ito

Beilstein J. Org. Chem. 2022, 18, 855–862, doi:10.3762/bjoc.18.86

• , Japan 10.3762/bjoc.18.86 Abstract This study describes the solid-state palladium-catalyzed cross-coupling between aryl halides and bis(pinacolato)diboron using ball milling. The reactions were completed within 10 min for most aryl halides to afford a variety of synthetically useful arylboronates in

• mill; borylation; cross-coupling; mechanochemistry; solid-state reaction; Introduction Arylboronic acid and its derivatives are indispensable reagents in modern synthetic chemistry because they have been frequently used for the preparation of many bioactive molecules, natural products, and functional

• , mechanochemical synthesis using ball milling has attracted considerable attention as an efficient solvent-free synthetic technique [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. Notably, the strong mechanical agitation provided by ball milling enables efficient solid-state organic