Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• . Thermodynamic and theoretical data provide hydride affinities, which correspond to the negative heat of formation for the combination of a hydride anion with a given cation in the gas phase (Figure 2) [26][29]. It is noteworthy that, in contrast to the hydride affinity scale, the Mayr scale considers energetic

Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination

• Ruichen Lan,
• Brock Yager,
• Yoonsun Jee,
• Cynthia S. Day and
• Amanda C. Jones

Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43

• nitrogen. Thus, the rate of intramolecular hydroamination is enhanced by a more nucleophilic nitrogen. Another qualitative interpretation is that rates are enhanced by carbonyl basicity. Gas-phase basicity measurements indicate that ureas are more basic than amides [47][50], and here the most Lewis base

Enhanced host–guest interaction between [10]cycloparaphenylene ([10]CPP) and [5]CPP by cationic charges

• Eiichi Kayahara,
• Yoshiyuki Mizuhata and
• Shigeru Yamago

Beilstein J. Org. Chem. 2024, 20, 436–444, doi:10.3762/bjoc.20.38

• present in solution when the solvent effect is negligible. Formation of complex 1 in the gas phase was highly exothermic with ΔG = −222 kJ mol−1 at 298.15 K and 1.00 atm, and this value is about two times higher than that of the complex formation of neutral [10]CPP⊃[5]CPP (ΔG = −114 kJ mol−1). Therefore

• , the same trend of the relative stability between [10]CPP⊃[5]CPP2+ and [10]CPP⊃[5]CPP was also observed in the gas phase. The significant increase in relative stability in the gas phase compared to the solution state is likely due to the overestimation of electronic interactions due to CT in the

Photochromic derivatives of indigo: historical overview of development, challenges and applications

• Gökhan Kaplan,
• Zeynel Seferoğlu and
• Daria V. Berdnikova

Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23

• isoindigo derivatives are photostable, and no photochromism was reported for these compounds till 2019, when Oomens and co-workers provided an evidence for the E–Z photoisomerization of the protonated isoindigo in the gas phase (Figure 16) [77]. The backward Z–E photoisomerization of the protonated

Electron-beam-promoted fullerene dimerization in nanotubes: insights from DFT computations

• Laura Abella,
• Gerard Novell-Leruth,
• Josep M. Ricart,
• Josep M. Poblet and
• Antonio Rodríguez-Fortea

Beilstein J. Org. Chem. 2024, 20, 92–100, doi:10.3762/bjoc.20.10

• singlet state [10]. Although only a few analyses of the reaction mechanisms have been studied due to the complexity of the system, several intermediates inside the CNT have been proposed [3][11][12], which may be different from those proposed to take place in the gas phase or in the solid state at high

• -dimensional space within the CNT and compared the results with those for the same reaction in the gas phase. We assumed that the cation radical mechanism takes place, that is, the ionized CNT generates a radical cation C60•+ that reacts with a C60 molecule to yield different C120•+ dimers. The energies for

• in the latter (Figure 1). Dimer 1-Cs is at our computational settings (PBE/PW), more than 15 kcal mol−1 higher in energy than dimer 1-D2h, the one characterized by X-ray crystallography in the solid state, both in the gas phase and inside the CNT. Similar lower stabilities for dimer 1-Cs are also

Optimizing reaction conditions for the light-driven hydrogen evolution in a loop photoreactor

• Pengcheng Li,
• Daniel Kowalczyk,
• Johannes Liessem,
• Mohamed M. Elnagar,
• Dariusz Mitoraj,
• Radim Beranek and
• Dirk Ziegenbalg

Beilstein J. Org. Chem. 2024, 20, 74–91, doi:10.3762/bjoc.20.9

• inert gas flow rate was increased from 25 to 75 mL min−1. This effect is attributed to an enhanced mass transfer of hydrogen from the photocatalyst to the gas phase. The relevant mass transport steps for hydrogen include the diffusion from the photocatalyst surface to the liquid bulk, transfer from the

• liquid bulk to liquid–gas interface, and transfer from liquid–gas interface to gas phase [43]. Since the inert gas was purged into the reactor continuously, the generated hydrogen could also directly be transferred from the photocatalyst surface to the gas phase if a gas bubble got in contact with the

• maximum hydrogen generation rate was 1.5 times higher at 740 rpm than at 430 rpm. This gives evidence that increased convection improves the mass transfer of generated hydrogen from the liquid phase to the gas phase or even directly from the catalyst to the gas phase. This is in line with the measured

GlAIcomics: a deep neural network classifier for spectroscopy-augmented mass spectrometric glycans data

• Thomas Barillot,
• Baptiste Schindler,
• Baptiste Moge,
• Elisa Fadda,
• Franck Lépine and
• Isabelle Compagnon

Beilstein J. Org. Chem. 2023, 19, 1825–1831, doi:10.3762/bjoc.19.134

• .19.134 Abstract Carbohydrate sequencing is a formidable task identified as a strategic goal in modern biochemistry. It relies on identifying a large number of isomers and their connectivity with high accuracy. Recently, gas phase vibrational laser spectroscopy combined with mass spectrometry tools have

• proposed to identify the presence of structural features in oligosaccharides based on their gas-phase IR spectra [11]. To the best of our knowledge, machine learning classification studies have not been reported to identify saccharides using MS–IR carbohydrate analysis. Here, we report a study of a

• approach is based on the IRMPD spectroscopic scheme (infrared multiple photon dissociation), which is the combination of mass spectrometry and IR spectroscopy. IRMPD is an action spectroscopy method that allows recording IR absorption spectra of isolated gas-phase ions, based on the measurement of the

Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

• Dayanne Martins,
• Roberta Lamosa,
• Talis Uelisson da Silva,
• Carolina B. P. Ligiero,
• Sérgio de Paula Machado,
• Daphne S. Cukierman and
• Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

• for hdz-CH3 (0.648 Å in the gas phase and 0.623 Å in water). However, the small RMSD values in all cases showed that the calculated structures correlated pretty well with the respective experimental ones [45][46]. The biggest differences between the theoretical structures and the experimental data

• errors of 2% (hdz-CH3) and 0% (hdz-NO2). In general, the structures calculated involving the IEFPCM formalism (water phase) displayed the best agreement with the experimental data. Regarding the vibrational characterization, infrared spectra were also calculated with both B3LYP/6-311G(d,p) – gas phase

• intensity bands, respectively, at 1519 and 1336 cm−1. These modes were calculated at 1608 and 1379 cm−1 in the gas phase. Although N-acylhydrazones are usually prone to undergo speciation in DMSO-d6 solution [47], 1H NMR measurements showed the existence of only one set of signals in the spectra of hdz-CH3

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• with poly(ethersulfone) [143]. Highly reactive gaseous species may also generate radicals on polymer surfaces. For example, atomic oxygen radical anions emitted from 12CaO⋅7Al2O3 crystals [144] were used to modify PVC and polystyrene [145][146]. Plasma is also a powerful gas-phase tool for polymer

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• dyads adopts a puckered geometry (i.e., nonplanar geometry). This is known for the PTZ moiety [69][70]. We also optimized the geometry of the dyads at the S1 and T1 states (Tables S1 and S2 in Supporting Information File 1). In gas phase or nonpolar solvents, the dihedral angles between the NI and the

• ) NI-PTZ-F, (b) NI-PTZ-Ph, (c) NI-PTZ-CH3, (d) NI-PTZ-OCH3, (e) NI-PTZ-C5, (f) NI-PTZ-F-O, (g) NI-PTZ-Ph-O, and (h) NI-PTZ-C5-O. Calculated at the B3LYP/6-31G(d) level of theory using Gaussian 09. Spin density surfaces of the dyads in the T1 state (gas phase) of (a) NI-PTZ-F, (b) NI-PTZ-Ph, (c) NI-PTZ

Strategies in the synthesis of dibenzo[b,f]heteropines

• David I. H. Maier,
• Barend C. B. Bezuidenhoudt and
• Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

• [36] via the polyphosphoric acid (PPA) catalysed cyclisation of 2,2'-diaminobibenzyl (20) at elevated temperatures (Scheme 3) [37][38]. 1.3 Catalytic dehydrogenation An early synthesis of 5H-dibenzo[b,f]azepine (1a) involved the gas phase dehydrogenation of 10,11-dihydro-5H-dibenzo[b,f]azepine (2a) to

Recommendations for performing measurements of apparent equilibrium constants of enzyme-catalyzed reactions and for reporting the results of these measurements

• Robert N. Goldberg,
• Robert T. Giessmann,
• Peter J. Halling,
• Carsten Kettner and
• Hans V. Westerhoff

Beilstein J. Org. Chem. 2023, 19, 303–316, doi:10.3762/bjoc.19.26

• been studied, the stoichiometries, the units used for concentrations, and the solvent. The basis for the stoichiometry should be reported for a binding reaction. If substances such as CO2, N2, and NH3 are reactants, one must specify if these substances are in solution or in the gas phase and give the

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

• significantly lower but more easily implemented level of theory (PBE0 functional [41], 6-31+G(d) basis set, gas phase), followed by calculation of the 31P NMR chemical shifts with the same PBE0 functional with the still-modest 6-311G(2d,2p) basis set. While the calculated fit to experimental values was

• complicated by water solvation, as well as ionization or aggregation of the phosphoric acid in water, and calculation as a gas-phase chemical shift is also unreasonable [51]. Because of these issues, other studies have used PH3 as an alternative theoretical reference standard [18][19], despite the fact that

• actual use of this compound requires a fairly extraordinary experimental setup [52][53]. An additional issue with PH3 involves the choice of using the gas-phase or liquid-phase experimental chemical shifts, which differ dramatically: the universally used value for the gas-phase chemical shift is −266.1

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

Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence

• Kaiyue Ye,
• Liyuan Cao,
• Davita M. E. van Raamsdonk,
• Zhijia Wang,
• Jianzhang Zhao,
• Daniel Escudero and
• Denis Jacquemin

Beilstein J. Org. Chem. 2022, 18, 1435–1453, doi:10.3762/bjoc.18.149

• ) NI-PTZ2, (d) NI-Ph-PTZ, and (e) NI-PhMe2-PTZ; the green and orange sheets show the planes of the donor and the receptor. Kohn–Sham frontier molecular orbitals (CAM-B3LYP/6-31G(d) in gas phase) involved in S1, T1, and T2 of NI-N-PTZ, NI-PTZ, NI-PTZ-O, NI-PTZ2, NI-Ph-PTZ, and NI-PhMe2-PTZ, based on the

1,4,6,10-Tetraazaadamantanes (TAADs) with N-amino groups: synthesis and formation of boron chelates and host–guest complexes

• Artem N. Semakin,
• Ivan S. Golovanov,
• Yulia V. Nelyubina and
• Alexey Yu. Sukhorukov

Beilstein J. Org. Chem. 2022, 18, 1424–1434, doi:10.3762/bjoc.18.148

• cage nitrogen atoms) and/or rotamers (restricted rotation around amide C–N bonds), which is well-known for amides and carbamates (Figure 4a). The activation barriers for the rotation across amide C–N bonds in 4a and 4c estimated by DFT (18.4 and 19.4 kcal/mol, respectively, ωB97XD/Def2TZVP, gas phase

• complexes is thermodynamically favored in the gas phase by 1–4 kcal/mol (ΔG°) showing rather weak bond character in these structures. Indeed, the guest molecules are liberated upon drying of the obtained crystal solvates in a vacuum with gentle heating. Interestingly, a higher preference in coordination of

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

• spectrometry (HRMS) (Figures S1–S24 in Supporting Information File 1), and melting point analysis. We modelled the electron density distribution in DiKTa-OBuIm and DiKTa-DPA-OBuIm using density functional theory (DFT) calculations in the ground state, at the PBE0/6-31G(d,p) level of theory in the gas phase

• ) the MR-TADF emitter DiKTa and selected derivatives, and (c) the ionic emitters in this work. (a) HOMO and LUMO electron density distribution and orbital energies of DiKTa-OMe and DiKTa-DPA-OMe calculated at the PBE0/6-31G(d,p) level of theory in the gas phase, isovalue = 0.02; (b) difference density

• plots and energies for the two lowest-lying singlet and triplet excited states for DiKTa-OMe and DiKTa-DPA-OMe calculated at SCS-CC2/cc-pVDZ in the gas phase (isovalue = 0.001). The blue color represents an area of decreased electron density, and yellow represents an increased electron density between

Dienophilic reactivity of 2-phosphaindolizines: a conceptual DFT investigation

• Nosheen Beig,
• Aarti Peswani and
• Raj Kumar Bansal

Beilstein J. Org. Chem. 2022, 18, 1217–1224, doi:10.3762/bjoc.18.127

• varying the values is followed. In view of this, we carried out all calculations in the gas phase only. Thus all geometries were optimized in the gas phase at the B3LYP/6-31+G(d) level of theory. Frequency calculations were done at the same level to determine zero-point correction and to characterize

Experimental and theoretical studies on the synthesis of 1,4,5-trisubstituted pyrrolidine-2,3-diones

• Nguyen Tran Nguyen,
• Vo Viet Dai,
• Nguyen Ngoc Tri,
• Luc Van Meervelt,
• Nguyen Tien Trung and
• Wim Dehaen

Beilstein J. Org. Chem. 2022, 18, 1140–1153, doi:10.3762/bjoc.18.118

• proposed based on computational results and the main product is formed favorably following the PES via the lowest ΔG# pathway in both the gas-phase and an ethanol solvent model. DFT calculations showed that kinetic selectivity is more significant than thermodynamic selectivity for forming main products

• ’ by 1.3 kcal·mol−1 in the gas phase or by 0.4 kcal·mol−1 in the ethanol solvent model. The transformation of 4a into 4a’ occurs with a small potential barrier of 0.5 kcal·mol−1 (in the gas phase) or 1.0 kcal·mol−1 (in ethanol). This process goes through TS1 by H displacement at the O–H bond of the O–H

• to form product 10ab and isomers from 4a/4a’ in the gas phase. The ΔG, ΔG# values for each stage in the PES at the gas phase are collected in Table 2. The 4a and 4a’ tautomers react with CH3NH2 to yield products, as detailed in Figure 4. All three C (C−O) sites in 4a, 4a’ are possible for interaction

Understanding the competing pathways leading to hydropyrene and isoelisabethatriene

• Shani Zev,
• Marion Ringel,
• Ronja Driller,
• Bernhard Loll,
• Thomas Brück and
• Dan T. Major

Beilstein J. Org. Chem. 2022, 18, 972–978, doi:10.3762/bjoc.18.97

• two byproducts, isoelisabethatrienes A and B. Fascinatingly, a single active site mutation (M75L) diverts the product distribution towards isoelisabethatrienes A and B. In the current work, we study the competing pathways leading to these products using quantum chemical calculations in the gas phase

• on the mechanistic details of the HP and IE pathways using computational methods in the gas phase. Gas-phase studies have been crucial in understanding terpene chemistry [10][11][12][13][14][15][16][17][18][19][20][21][22]. This work sheds light on the thermodynamic and kinetic parameters of the

• ). We studied the inherent chemistry of the reaction leading to HP and IE using gas-phase calculations. This provided the free energy of distinct carbocation intermediates and transition states along the proposed reaction path leading to products in the gas phase. The gas phase is a natural choice as a

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

• highly delocalised bipolaron states [69]. Computation of structure Since all attempts to grow crystals of EtH-T-DI-DTT failed, we predicted the structure with a density functional theory (DFT) gas-phase optimisation using the B3LYP[70][71]/6-311g(d,p) [72] level of theory, using both the Gaussian09 [73

Terpenoids from Glechoma hederacea var. longituba and their biological activities

• Dong Hyun Kim,
• Song Lim Ham,
• Zahra Khan,
• Sun Yeou Kim,
• Sang Un Choi,
• Chung Sub Kim and
• Kang Ro Lee

Beilstein J. Org. Chem. 2022, 18, 555–566, doi:10.3762/bjoc.18.58

• “Mixed torsional/Low-mode sampling” in the MMFF force field. The searches were implemented in the gas phase with a 15 kJ/mol energy window limit and 10,000 maximum number of steps to explore all potential conformers. The Polak–Ribiere conjugate gradient (PRCG) method was utilized to minimize conformers

• with 10,000 iterations and a 0.001 kJ (mol Å)−1 convergence threshold on the root mean quare (RMS) gradient. All the conformers of 1–3 within 3 kJ/mol of each global minimum were subjected to geometry optimization using the Gaussian 16 package (Gaussian Inc.) in the gas phase at B3LYP/6-31G(d) level

A resorcin[4]arene hexameric capsule as a supramolecular catalyst in elimination and isomerization reactions

• Tommaso Lorenzetto,
• Fabrizio Fabris and
• Alessandro Scarso

Beilstein J. Org. Chem. 2022, 18, 337–349, doi:10.3762/bjoc.18.38

• catalysts under harsher experimental conditions with T higher than 100 °C in the gas phase [61]. More importantly, the product distribution observed is rather unusual if compared to many other heterogeneous catalytic systems known in the literature for leading to higher selectivity for camphene [62][63][64

1,2-Naphthoquinone-4-sulfonic acid salts in organic synthesis

• Ruan Carlos B. Ribeiro,
• Patricia G. Ferreira,
• Amanda de A. Borges,
• Luana da S. M. Forezi,
• Fernando de Carvalho da Silva and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 53–69, doi:10.3762/bjoc.18.5

• equilibrium between A and B using semiempirical calculations (AM1 and PM3) and DFT (B3LYP/6-31G(d)) in the gas phase and water, where it was observed that in the gas phase B is the most stable, while in water A is formed, which is in agreement with the experimental results reported in the literature. There

DABCO-promoted photocatalytic C–H functionalization of aldehydes

• Bruno Maia da Silva Santos,
• Mariana dos Santos Dupim,
• Cauê Paula de Souza,
• Thiago Messias Cardozo and
• Fernanda Gadini Finelli

Beilstein J. Org. Chem. 2021, 17, 2959–2967, doi:10.3762/bjoc.17.205

• , endergonic by 18.8 kcal·mol−1 (gas phase) and 20.1 kcal·mol−1 (1,4-dioxane with PCM); almost thrice the Gibbs free energy for the same reaction with DABCO as a HAT abstractor. The barrierless character is supported by NEB-TS calculations (vide infra) (Supporting Information File 1, Figure S16). Both these

• the reaction step with 1 in gas phase and in 1,4-dioxane. The HAT reaction step catalyzed with quinuclidine is exergonic (−8.0 kcal·mol−1), while the reaction step involving DABCO is endergonic (+6.8 kcal·mol−1), in agreement with what would be expected from BDE and BDFE analyses. The solvent effect

• leads to only minor differences in the thermodynamics of the reaction and do not change the qualitative picture. The HAT step carried out with DABCO presents a kinetic barrier of 16.9 kcal·mol−1 in the gas phase while the quinuclidine-catalyzed reaction is predicted to be barrierless as shown in Figure