Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

• recommend exploring the article for further details [95]. Molecules with functional groups such as carboxylic acid present complex surface topologies from bridging and bidentate binding modes [91]. Yoshida and co-workers studied the adsorption of benzene derivatives on TiO2 surfaces by solid-state NMR and

Synthesis of 3-alkenylindoles through regioselective C–H alkenylation of indoles by a ruthenium nanocatalyst

• Abhijit Paul,
• Debnath Chatterjee,
• Srirupa Banerjee and
• Somnath Yadav

Beilstein J. Org. Chem. 2020, 16, 140–148, doi:10.3762/bjoc.16.16

• -carboxylic acid was anchored to Wang resin and then subjected to the conditions for the alkenylation reaction with 2a using the solid catalyst (3 mg) for 48 h. After that, the reaction mixture was worked up, and the solid product was isolated and subjected to solid-state NMR spectroscopy. The results were

Carbazole-functionalized hyper-cross-linked polymers for CO₂ uptake based on Friedel–Crafts polymerization on 9-phenylcarbazole

• Dandan Fang,
• Xiaodong Li,
• Meishuai Zou,
• Xiaoyan Guo and
• Aijuan Zhang

Beilstein J. Org. Chem. 2019, 15, 2856–2863, doi:10.3762/bjoc.15.279

• carbon. Based on the above peaks in the solid state NMR, the Friedel–Crafts polymerization product was confirmed. TGA analysis The thermal stability of HCPs was investigated by TGA tests (Figure 3 and Supporting Information File 1, Figure S3). A slight weight loss at 100 °C was observed for P2, P4, P5

Computational characterization of enzyme-bound thiamin diphosphate reveals a surprisingly stable tricyclic state: implications for catalysis

• Ferran Planas,
• Michael J. McLeish and
• Fahmi Himo

Beilstein J. Org. Chem. 2019, 15, 145–159, doi:10.3762/bjoc.15.15

• for the APH+ form. However, solid-state NMR using 15N and 13C-labeled ThDP has been used to identify APH+ on pyruvate decarboxylase and the E1 component of the pyruvate dehydrogenase complex [18]. In addition to the plethora of experimental investigations, a number of computational studies have

Calixazulenes: azulene-based calixarene analogues – an overview and recent supramolecular complexation studies

• Paris E. Georghiou,
• Shofiur Rahman,
• Abdullah Alodhayb,
• Hidetaka Nishimura,
• Jaehyun Lee,
• Atsushi Wakamiya and
• Lawrence T. Scott

Beilstein J. Org. Chem. 2018, 14, 2488–2494, doi:10.3762/bjoc.14.225

• solvents prevented a fuller examination of its potential supramolecular properties with fullerenes, a topic of particular interest to us [18]. Therefore, the solid state supramolecular complexation properties of 5 were experimentally studied using solid state NMR and XRD experiments, and also theoretically

• , using a DFT analysis [17]. We previously used a similar solid-state NMR approach to study the solid-state supramolecular properties of tetra-6-tert-butylcalix[4]azulene (4) [19]. Unlike these two studies, however, in our first study on calixazulenes which we reported in 2015, we were able to demonstrate

Selective formation of a zwitterion adduct and bicarbonate salt in the efficient CO₂ fixation by N-benzyl cyclic guanidine under dry and wet conditions

• Yoshiaki Yoshida,
• Naoto Aoyagi and
• Takeshi Endo

Beilstein J. Org. Chem. 2018, 14, 2204–2211, doi:10.3762/bjoc.14.194

• characterized in detail by elemental analysis, FTIR-ATR, solid-state NMR, TGA, and DFT calculation. These analytical results obviously revealed the formation of a zwitterion adduct and bicarbonate salt from N-benzyl cyclic guanidine and CO2. Especially, the zwitterion adduct of the monocyclic guanidine

• adduct and bicarbonate salt between CO2 and N-benzyl cyclic guanidine 1. The structures of the zwitterionic adduct and bicarbonate salt were analyzed in detail and proved by elemental analysis, FTIR-ATR, solid-state NMR, TGA, and DFT calculations. In this report, the zwitterionic adduct of the monocyclic

• from 1 under dry (in anhydrous CH3CN) and wet (in CH3CN containing an equimolar amount of water for 1) conditions, respectively. Both of 2 and 3 were isolated as white solids and their structures were characterized in detail by elemental analysis, FTIR-ATR, solid-state NMR, TGA, and DFT calculation

A hemicryptophane with a triple-stranded helical structure

• Augustin Long,
• Olivier Perraud,
• Erwann Jeanneau,
• Christophe Aronica,
• Jean-Pierre Dutasta and
• Alexandre Martinez

Beilstein J. Org. Chem. 2018, 14, 1885–1889, doi:10.3762/bjoc.14.162

• observed in solid state. NMR studies suggest that this propeller-like arrangement also occurs in solution. Further investigations are in progress in order to propagate the chirality of the CTV to even more remote opposite sites through the formation of such triple helical structures. 1H NMR spectrum of 1

Hyper-reticulated calixarene polymers: a new example of entirely synthetic nanosponge materials

• Alberto Spinella,
• Marco Russo,
• Antonella Di Vincenzo,
• Delia Chillura Martino and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2018, 14, 1498–1507, doi:10.3762/bjoc.14.127

• was assessed by means of FTIR and 13C{1H} CP-MAS solid-state NMR techniques, whereas morphological characterization was provided by SEM microghaphy. The materials were proved to possess pH-dependent sequestration abilities, due to the presence of the weakly basic triazole linkers. Sequestration

• ; solid-state NMR; Introduction Nanosponges (NSs) [1][2][3] constitute an emerging area of both materials chemistry and supramolecular chemistry due to their peculiar properties, which have been object of an increasing interest during the last years. These materials are constituted by hyper-reticulated

• between the reactive groups during the construction of the polymer network, as compared with the flexible linkers A1–A3 (see below). Solid-state NMR characterization The CP-MAS solid-state NMR technique has been proven a versatile and powerful tool for the structural characterization of materials and

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

• thermogravimetric analysis (described below). 13C{1H} CP-MAS NMR. The solid-state NMR spectra of fisetin, γ-CD hydrate and γ-CD·fisetin are depicted in Figure 2. The spectrum of fisetin presents some well-resolved resonances that are ascribed to the carbonyl and C1, C7, C8, C9, and C6’ carbon atoms by comparison

Mechanochemical synthesis of thioureas, ureas and guanidines

• Vjekoslav Štrukil

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

• products were structurally characterized by solid-state analytical methods such as powder X-ray diffraction (PXRD) and solid-state NMR (ssNMR) spectroscopy. In this way, mechanochemical organic synthesis and solid-state analysis are incorporated into the paradigm of solvent-free synthetic organic research

Dynamics and interactions of ibuprofen in cyclodextrin nanosponges by solid-state NMR spectroscopy

• Monica Ferro,
• Franca Castiglione,
• Nadia Pastori,
• Carlo Punta,
• Lucio Melone,
• Walter Panzeri,
• Barbara Rossi,
• Francesco Trotta and
• Andrea Mele

Beilstein J. Org. Chem. 2017, 13, 182–194, doi:10.3762/bjoc.13.21

• on passing from the empty CDNS to the drug-loaded CDNS, thus showing that the drug encapsulation can be seen as the formation of a real supramolecular aggregate rather than a conglomerate of two solid components. Finally, the structural features obtained from the different solid-state NMR approaches

• reported matched the information from powder X-ray diffraction profiles. Keywords: cross-polarization; cyclodextrin; ibuprofen; nanosponges; solid-state NMR; Introduction In the last ten years cyclodextrin nanosponges (CDNS) polymer materials received great attention as promising new materials in several

• is the racemic mixture (R,S)-ibuprofen. Moreover, solid-state NMR spectra revealed that in all tablet samples, ibuprofen is present in acidic form IbuH with different contents of bound water within tablets [12] depending on the formulation. In this work the racemic (R,S)-ibuprofen sodium salt (IbuNa

Polydisperse methyl β-cyclodextrin–epichlorohydrin polymers: variable contact time ¹³C CP-MAS solid-state NMR characterization

• Isabelle Mallard,
• Davy Baudelet,
• Franca Castiglione,
• Monica Ferro,
• Walter Panzeri,
• Enzio Ragg and
• Andrea Mele

Beilstein J. Org. Chem. 2015, 11, 2785–2794, doi:10.3762/bjoc.11.299

• confirmed that the three polymers are morphologically similar. Thus the combined use of TCH and T1ρ can be helpful for the characterization and fine tuning of imprinted polymeric matrices. Keywords: dynamic cross-polarization; epichlorohydrin; imprinted; insoluble CRYSMEB polymers; solid-state NMR

• recognition sites for the template molecule. As a matter of fact, high-resolution solid-state NMR is a powerful tool to characterize the structure of polymers [23][24] and to study their dynamics [25][26]. Crini has reported previously a solid-state NMR spectroscopy study [27][28] of β-cyclodextrin polymers

• . At this time, no discussion concerning the NMR spectroscopic characterization of insoluble imprinted CRYSMEB polymers has been reported. The main purpose of these measurements was to explore possible applications of solid-state NMR spectroscopy for the characterization, at the atomic level, of

An experimental and theoretical NMR study of NH-benzimidazoles in solution and in the solid state: proton transfer and tautomerism

• Carla I. Nieto,
• Pilar Cabildo,
• M. Ángeles García,
• Rosa M. Claramunt,
• Ibon Alkorta and
• José Elguero

Beilstein J. Org. Chem. 2014, 10, 1620–1629, doi:10.3762/bjoc.10.168

• of molecules in solution to the point that the assignment of some signals that become magnetically equivalent (isochronous) [9][10] by fast proton exchange has been much neglected. With the advent of solid-state NMR spectroscopy and the suppression of prototropic tautomerism, the assignment problem

Structure of 1,5-benzodiazepinones in the solid state and in solution: Effect of the fluorination in the six-membered ring

• Marta Pérez-Torralba,
• Rosa M. Claramunt,
• M. Ángeles García,
• Concepción López,
• M. Carmen Torralba,
• M. Rosario Torres,
• Ibon Alkorta and
• José Elguero

Beilstein J. Org. Chem. 2013, 9, 2156–2167, doi:10.3762/bjoc.9.253

• refinement data for 1 and 2. Supporting Information Variable temperature 1H NMR spectra, 13C, 15N, 19F solid state NMR spectra; Table S1 containing calculated and some experimental 1H, 13C and 15N chemical shifts (δ, ppm) of compounds 3a to 6a; Geometry (Å), energy (hartree) and number of imaginary

A³-Coupling catalyzed by robust Au nanoparticles covalently bonded to HS-functionalized cellulose nanocrystalline films

• Jian-Lin Huang,
• Derek G. Gray and
• Chao-Jun Li

Beilstein J. Org. Chem. 2013, 9, 1388–1396, doi:10.3762/bjoc.9.155

• novel nanocomposite catalyst AuNPs@HS-CNC. The uniform, fine AuNPs were made by the reduction of HAuCl4 solution with thiol (HS-) group-functionalized CNC films. The AuNPs@HS-CNC nanocomposites were examined by X-ray photoelectron spectroscopy (XPS), TEM, ATR-IR and solid-state NMR. Characterizations

Methylidynetrisphosphonates: Promising C₁ building block for the design of phosphate mimetics

• Vadim D. Romanenko and
• Valery P. Kukhar

Beilstein J. Org. Chem. 2013, 9, 991–1001, doi:10.3762/bjoc.9.114

• salts (Figure 1) [7]. Structural features of the trisphosphonate 18 were studied by NMR spectroscopy and by single-crystal X-ray diffraction. Only one 31P NMR signal is observable for three equivalent phosphonate moieties in CHCl3. In contrast, the 31P solid-state NMR spectrum of 18 revealed three

Cyclodextrin-based nanosponges as drug carriers

• Francesco Trotta,
• Marco Zanetti and
• Roberta Cavalli

Beilstein J. Org. Chem. 2012, 8, 2091–2099, doi:10.3762/bjoc.8.235

• elsewhere [14]. Here we simply wish to stress that primary hydroxy groups are mainly involved in the formation of a network as shown by FTIR–ATR, Raman and solid-state NMR analyses [15]. Moreover, the elastic properties of cyclodextrin nanosponges were determined by analysis of the spectral modification of

Restructuring polymers via nanoconfinement and subsequent release

• Alan E. Tonelli

Beilstein J. Org. Chem. 2012, 8, 1318–1332, doi:10.3762/bjoc.8.151

• their ternary coalesced blend (Figure 9). Solid-state NMR observations [13C observed 1H spin-lattice relaxation times recorded in the rotating frame, T1ρ(1H)] of the three polymers in their ternary blend confirmed their intimate molecular mixing on a scale less than 5 nm. Thermal stability of coalesced

Laterally substituted symmetric and nonsymmetric salicylideneimine-based bent-core mesogens

• Sonja Findeisen-Tandel,
• Wolfgang Weissflog,
• Ute Baumeister,
• Gerhard Pelzl,
• H. N. Shreenivasa Murthy and
• Channabasaveshwar V. Yelamaggad

Beilstein J. Org. Chem. 2012, 8, 129–154, doi:10.3762/bjoc.8.15

• and on the direction of the linking groups, which connect both molecular legs to the central phenyl ring, as we know from solid state NMR studies. For 2-methylresorcinol bisbenzoates, for example, the bending angle amounts to about 120° [58]. In contrast, for isomeric diphenyl 2-methylisophthalates

Miniemulsion polymerization as a versatile tool for the synthesis of functionalized polymers

• Daniel Crespy and
• Katharina Landfester

Beilstein J. Org. Chem. 2010, 6, 1132–1148, doi:10.3762/bjoc.6.130

• polymerization of n-butyl cyanoacrylate both in macroemulsion and in miniemulsion in the presence of an oil (caprylic/capric triglyceride) with water as continuous phase [83]. The latter method yielded capsules with a higher stability. Solid-state NMR spectroscopy showed that the polymer was in contact with both

A practical synthesis of the ¹³C/¹⁵N- labelled tripeptide N-formyl- Met-Leu-Phe, useful as a reference in solid- state NMR spectroscopy

• Sven T. Breitung,
• Jakob J. Lopez,
• Gerd Dürner,
• Clemens Glaubitz,
• Michael W. Göbel and
• Marcel Suhartono

Beilstein J. Org. Chem. 2008, 4, No. 35, doi:10.3762/bjoc.4.35

• 13C/15N-labelled tripeptide 1 could be isolated in a typical batch. This peptide can be easily crystallised and is therefore well suited as a standard sample for setting up solid-state NMR experiments. Keywords: Fmoc solid phase peptide synthesis; formylation; f-MLF; magic-angle spinning; Wang resin

• ; Introduction There appears to be a general lack of widely available and standardised samples for setting up new solid-state NMR experiments. Such a standard sample should show a small 13C and 15N linewidth and a short 1H T1 relaxation time. It should contain a number of molecular groups with different chemical

• shifts for setting up correlation spectra. The 13C/15N-labelled tripeptide N-formyl-Met-Leu-Phe-OH (f-MLF-OH) (1) has been shown in a number of solid-state NMR studies to fulfil these criteria. It has been used in great detail to examine spin dynamics in peptide and for distance measurements [1][2][3][4