Thienothiophene-based organic light-emitting diode: synthesis, photophysical properties and application

• Recep Isci and
• Turan Ozturk

Beilstein J. Org. Chem. 2023, 19, 1849–1857, doi:10.3762/bjoc.19.137

• . The high thermal stability is profitable for the preparation of stable and durable OLED devices. Computational chemistry Ground-state geometry optimization of DMB-TT-TPA (8) was performed using density functional theory (DFT) calculations with the Gaussian 16 software at the B3LYP/6-31G (d,p) level

• and TT units, the LUMO was found to be delocalized through the dimesitylboron and TT ring, the results being in line with the experimental values of our previous study [23]. On the basis of the optimized ground-state geometry, time-dependent DFT (TD-DFT) calculations were conducted in THF to

• computation data, 1H and 13C NMR spectra. Acknowledgements The authors thank Dilara Gunturkun for DFT calculations, Istanbul Technical University (ITU). Funding The authors thank THD-2023-44904, PTA-2023-44900, TGA-2023-44077, TDA-2022-43696 numbered ITU BAP Projects and 122Z568 numbered TUBITAK 1001 Project

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• esters 8, 9 without the requirements of phosphine or other photocatalysts (Scheme 5). Through the use of density functional theory (DFT) calculations, they elucidated the mechanism behind this process. It was revealed that the formation of a photoactive EDA complex, which subsequently generated alkyl

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• proposed mechanism is only tentative and should be confirmed by further analyses and theoretical calculations. In any case, the addition of proton sources should be beneficial for the CO2 pathway, and in the system, we studied so far, the only plausible proton source is the bezimidazolidine derivative

Charge carrier transport in perylene-based and pyrene-based columnar liquid crystals

• Alessandro L. Alves,
• Simone V. Bernardino,
• Carlos H. Stadtlober,
• Edivandro Girotto,
• Giliandro Farias,
• Rodney M. do Nascimento,
• Sergio F. Curcio,
• Thiago Cazati,
• Marta E. R. Dotto,
• Juliana Eccher,
• Leonardo N. Furini,
• Hugo Gallardo,
• Harald Bock and
• Ivan H. Bechtold

Beilstein J. Org. Chem. 2023, 19, 1755–1765, doi:10.3762/bjoc.19.128

• molecular π-stacking inside the columns. The pyrene crystallizes bellow 166 °C, preserving the close-packed columnar rectangular structure of the mesophase. Photophysical analysis and numerical calculations assisted the interpretation of positive and negative charge carrier mobilities obtained from fitting

• charge transport behavior. DFT calculations assisted the interpretation of electron and hole migration mechanism using the frontier orbital energies and the conjugation within the π-system. Results and Discussion The syntheses of 1 and 2 were previously published in [25] and [26], respectively. 1 is a

• ][48]. RIJ requires the specification of an auxiliary basis set for the Coulomb part (Def2/J) and a numerical integration grid for the exchange part (DefGrid-2) [49]. Analytical harmonic vibrational frequency calculations were conducted to verify if the ground state is a minimum on the potential energy

Unprecedented synthesis of a 14-membered hexaazamacrocycle

• Anastasia A. Fesenko and
• Anatoly D. Shutalev

Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126

• 156.6, 152.1, 151,9, 128.3, 105.6 ppm and 160.9, 158.9, 157.4, 123.3, 98.4 ppm, respectively. The corresponding experimental shifts (155.0, 151.8, 149.9, 128.4, 105.4 ppm) were in good agreement with the structure 8. It is noteworthy that the DFT B3LYP/6-311++G(d,p) calculations using the PCM solvation

• pyrazolopyrimidine 8 into macrocycle 5 in MeOH solution were estimated by the DFT B3LYP/6-311++G(d,p) calculations. Relative Gibbs free energies of the starting, final, and intermediate molecular systems (Figure 1) were calculated using the Gibbs free energies for the most stable isomers of 8, macrocycle 5

• that the geometry of the intermediate bis-amidrazone C facilitates macrocycle 5 formation. The DFT B3LYP/6-311++G(d,p) calculations of ten different tautomers and stereoisomers of bis-amidrazone C (DMSO and MeOH solutions) revealed that the structure shown in Scheme 6 is the most stable. Clearly, 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

• liquors and, in both cases, XRD confirmed the obtention of the (E)-isomer, in an anti-conformation. Computational calculations (gas and water phases) were performed in order to confirm some of the structural and vibrational aspects of the compounds. An important intramolecular H bond involving the

• compounds are stable at physiological-like conditions, especially the methyl-derived one, which qualifies them for further toxicological and activity studies, such as those involving trivalent metal ions sequestering in the context of neurodegenerative diseases. Keywords: DFT calculations; N-acylhydrazones

• calculate the electrostatic potential over an electronic density map as well. For hdz-NO2, results show the alternated slipped stack motif involves the assembly of portions with opposite electrostatic potentials. Computational calculations were performed in order to confirm some of the structural and

A deep-red fluorophore based on naphthothiadiazole as emitter with hybridized local and charge transfer and ambipolar transporting properties for electroluminescent devices

• Suangsiri Arunlimsawat,
• Patteera Funchien,
• Pongsakorn Chasing,
• Atthapon Saenubol,
• Taweesak Sudyoadsuk and
• Vinich Promarak

Beilstein J. Org. Chem. 2023, 19, 1664–1676, doi:10.3762/bjoc.19.122

• MALDI-TOF-MS techniques. To examine the electronic properties of D–A TPECNz, density functional theory (DFT) calculations at the B3LYP level of theory with the 6-31G(d,p) basis set were performed. It has been previously reported that the twist angle of the D–A segment has a significant role in

• . To further figure out excited-state properties of TPECNz, the natural transition orbitals (NTOs) of singlet (S) and triplet (T) excited states were executed based on time-dependent (TD)-DFT calculations at the CAM-B3LYP/6-31G(d) level of theory. As shown in Figure 1b, the hole and particle of TPECNz

• characteristics of HLCT and weak AIE were clearly evidenced by a solvatochromic study, emission in THF/water investigation, and theoretical calculations. These synergetic properties could benefit for effective utilization of excitons in the OLED. A collaborative consequence of its D–A–D-type structure, a strong

Benzoimidazolium-derived dimeric and hydride n-dopants for organic electron-transport materials: impact of substitution on structures, electrochemistry, and reactivity

• Swagat K. Mohapatra,
• Khaled Al Kurdi,
• Samik Jhulki,
• Georgii Bogdanov,
• John Bacsa,
• Maxwell Conte,
• Tatiana V. Timofeeva,
• Seth R. Marder and
• Stephen Barlow

Beilstein J. Org. Chem. 2023, 19, 1651–1663, doi:10.3762/bjoc.19.121

• previously reported for the Y = cyclohexyl, R = R' = H derivative 1e2 (1.640(4) Å) [14], despite DFT calculations indicating that the former dimer is considerably more weakly bonded [8][14] and kinetic evidence for the “cleavage-first” mechanism occurring in doping reactions using 1b2 but not 1e2 (see below

• according to: where ΔGdiss(12) is the free-energy change for dissociation of 12 to 1• (dissociation energetics are not estimated in the present work, but have been estimated using DFT calculations for 1b–e2 in previous works [8][14] and, in favorable cases, can be experimentally estimated using electron

• localized; indeed DFT calculations for the Y = alkyl 1e• derivative indicate spin density almost entirely on the 2-position of the five-membered ring, while for Y = aryl and metallocenyl examples 1b•, 1c•, and 1d• there is substantial spin delocalization onto the Y-substituents [14][55]. Different extents

Sulfur-containing spiroketals from Breynia disticha and evaluations of their anti-inflammatory effect

• Ken-ichi Nakashima,
• Naohito Abe,
• Masayoshi Oyama,
• Hiroko Murata and
• Makoto Inoue

Beilstein J. Org. Chem. 2023, 19, 1604–1614, doi:10.3762/bjoc.19.117

• electrospray ionization HRESIMS analysis, and quantum chemical electronic CD calculations. Furthermore, the absolute configurations of sugar residues were determined by derivatization of the hydrolysates with ʟ-cysteine methyl ester and o-tolyl isothiocyanate followed by HPLC analysis. The anti-inflammatory

• ′, and 24 conformers for 3. The geometry of each conformer was optimized using DFT calculations at the B3LYP/6-31G(d) level of theory [20][21] with the conductor-like polarizable continuum model (CPCM) solvent model (MeOH) and Gibbs free energy was calculated subsequent frequency calculations. Time

• -dependent (TD)-DFT calculations at the B3LYP/6-31+G(d,p) level with CPCM solvent model (MeOH) [22] were performed for the optimized conformers. The resulting ECD spectra calculated for each conformer were averaged using Boltzmann populations evaluated at 300 K from Gibbs free energy calculated from the

Complexes of resorcin[4]arene with secondary amines: synthesis, solvent influence on “in-out” structure, and theoretical calculations of non-covalent interactions

• Waldemar Iwanek

Beilstein J. Org. Chem. 2023, 19, 1525–1536, doi:10.3762/bjoc.19.109

• , finally, the structure with the lowest energy, with the functional PBE0-D4/mTZVPP/CPCM. The Hartree–Fock plus London dispersion (HFLD) method was used for the study of non-covalent interactions (NCI). The calculations lead to the conclusion that a reduction in electrostatic interactions and an increase in

• exchange and dispersion interactions in CHCl3 in relation to DMSO are the driving forces behind the placement of sec-amine molecules into the R[4]A cavity and the formation of “in” type complexes. Keywords: complexes; DFT calculations; hydrogen bond; resorcin[4]arene; supramolecular chemistry

• atoms, presenting a challenging and time-consuming task for geometry optimization calculations and screening via DFT methods. Recent advancements have introduced fast semi-empirical DFT methods such as xTB [15], which enable their use in preliminary screening for molecular dynamics or searching for

Unraveling the role of prenyl side-chain interactions in stabilizing the secondary carbocation in the biosynthesis of variexenol B

• Moe Nakano,
• Rintaro Gemma and
• Hajime Sato

Beilstein J. Org. Chem. 2023, 19, 1503–1510, doi:10.3762/bjoc.19.107

• possibility of through-space interactions with prenyl side chains using DFT calculations. Our calculations show that (i) the unstable secondary carbocation is stabilized by the cation–π interaction from prenyl side chains, thereby lowering the activation energy, (ii) the four-membered ring formation is

• , computational chemistry including DFT [5][6][7][8][9], QM/MM [10][11][12][13][14][15][16] and QM/MM MD [14][15][16][17] calculations have been used for the biosynthetic studies of terpene/terpenoids [18]. Terpene-forming reactions, which involve various types of carbocation species stabilized by

• investigated the biosynthetic pathways using DFT calculations to validate the above-mentioned aspects. Results and Discussion The detailed structures of the intermediates and transition states were elucidated by computational analysis. Interestingly, we have found an interaction between the secondary

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• first thiolation and intramolecular cyclization of propargyl azides the removal of N2 and a proton. Subsequently, monothiolated perroles were subjected to the second thiolation process to prepare 3,4-bisthiolated pyrroles. Cyclic voltammetry and DFT calculations revealed that the 3,4-bisthiolated

Cyclization of 1-aryl-4,4,4-trichlorobut-2-en-1-ones into 3-trichloromethylindan-1-ones in triflic acid

• Vladislav A. Sokolov,
• Andrei A. Golushko,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2023, 19, 1460–1470, doi:10.3762/bjoc.19.105

• , the O-protonated forms ArC(=OH+)CH=CHCCl3, which are then cyclized into the target CCl3-indanones. These cations have been studied experimentally by means of NMR spectroscopy in TfOH and theoretically by DFT calculations. Under the same superacidic conditions in TfOH, CCl3-hydroxy ketones (1-aryl

• =CHC(=O)Me] with arenes in Brønsted superacid TfOH (triflic acid, CF3SO3H) furnishes 3-methyl-1-trichloromethylindenes (Scheme 1a) [11]. Based on NMR analysis in TfOH and theoretical DFT calculations, it has been found that the reaction proceeds through an intermediate formation of the O-protonated

• calculations, and to study their intramolecular cyclization in triflic acid into the synthetically and medicinally relevant (see recent reviews [12][13][14][15][16][17][18]) indan-1-ones. Results and Discussion The synthesis of 1-aryl-4,4,4-trichloro-3-hydroxybutan-1-ones (CCl3-hydroxy ketones) 1a–o was

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• as σ-donor ligands only. However, subsequent experimental [18] and theoretical [19] studies revealed that a simultaneous back donation from the d-orbital of the metal to the π*-orbital of the NHC occurs in these species, which was also corroborated by energy decomposition analysis (EDA) calculations

• on C1 enhancing its nuceophilicity (Figure 9). The Mulliken charge, obtained from the NBO calculations, was found to be almost double at the C–H atom in the complexed alkyne (−0.294) as compared to the free alkyne (−0.129). Furthermore, as depicted in Figure 10, the HOMO–LUMO energy gap in the NHC–Cu

Organic thermally activated delayed fluorescence material with strained benzoguanidine donor

• Alexander C. Brannan,
• Elvie F. P. Beaumont,
• Nguyen Le Phuoc,
• George F. S. Whitehead,
• Mikko Linnolahti and
• Alexander S. Romanov

Beilstein J. Org. Chem. 2023, 19, 1289–1298, doi:10.3762/bjoc.19.95

• region of ca. 380–460 nm with ε up to 1900 M−1 cm−1 (Table 2). Both loCT and deCT bands are observed for the benchmark material 4CzIPN [16] while originating from HOMO to LUMO transition in line with the theoretical calculations (Tables S1, S3, and S4, Supporting Information File 1). All CT bands

• experience a very weak solvatochromic effect with increasing solvent polarity from cyclohexane to dichloromethane. This indicates only minor change of the dipole moment upon vertical excitation from S0 (6.4 D) to S1 (7.2 D) excited states according to the TD-DFT theoretical calculations (Table S2, Supporting

• π-conjugation. The twisted structure of the 4BGIPN ensures that the donor groups accommodate the highest occupied molecular orbital (HOMO) while the acceptor 4,6-dicyanobenzene moiety contains the lowest unoccupied molecular orbital (LUMO) and is supported by the TD-DFT calculations. A comparison of

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• the reaction mechanism supported by DFT calculations and concluded that FeF2 plays an important redox role in assisting the cleavage of oxidants and the oxidation of carbon radicals to cationic intermediates of oxygen. CDC reactions between C(sp3)–H/C(sp)–H bonds catalyzed by iron have been reported

Cyanothioacetamides as a synthetic platform for the synthesis of aminopyrazole derivatives

• Valeriy O. Filimonov,
• Alexandra I. Topchiy,
• Vladimir G. Ilkin,
• Tetyana V. Beryozkina and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2023, 19, 1191–1197, doi:10.3762/bjoc.19.87

• ) which were used in all calculations. The final R1 = 0.0403, wR2 = 0.0956 (I > 2σ(I)) and R1 = 0.0510, wR2 = 0.1042 (all data). Largest diff. peak/hole 0.281/−0.285 ēÅ−3. 6e: Crystal data for C15H15F3N4OS (M = 356.37 g/mol): triclinic, space group P-1 (no. 2), a = 6.1592(10) Å, b = 12.0568(18) Å, c

• = 12.1206(19) Å, α = 109.032 (14)°, β = 101.540 (13)°, γ = 100.648 (13), V = 802.7(2) Å3, Z = 2, μ(Mo Kα) = 0.244 mm−1, Dcalc = 1.474 g/cm3, 5870 reflections measured (6.154° ≤ 2Θ ≤ 58.47°), 3676 unique (Rint = 0.0326, Rsigma = 0.0537) were used in all calculations. The final R1 = 0.0513, wR2 = 0.1241 (I

• , Dcalc = 1.452 g/cm3, 7847 reflections measured (4.794° ≤ 2Θ ≤ 58.972°), 3663 unique (Rint = 0.0461, Rsigma = 0.0641) were used in all calculations. The final R1 = 0.0580, wR2 = 0.1295 (I > 2σ(I)) and R1 = 0.0993, wR2 = 0.1673(all data). Largest diff. peak/hole 0.244/−0.450 ēÅ−3. The experiments were

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• energy adduct had fluoride residing in the weaker σ-hole (syn to the β-dicarbonyl) [16]. These calculations showed that a reductive elimination event was operative from both IntA/IntB, with a >25 kcal/mol energy difference between transitions states of the observed fluorination (TSA, path A) versus that

• calculations for enaminone synthesis from iodonium ylides and thioamides. Crystal structures of 76c (top) and 76e (bottom) [101], (CCDC# 2104180 & 2104181) [143][144]. Outline of possible reaction pathways between iodonium ylides and Lewis basic nucleophiles (top); and, reaction between 6 and HCl to give 7, as

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

Five new sesquiterpenoids from agarwood of Aquilaria sinensis

• Hong Zhou,
• Xu-Yang Li,
• Hong-Bin Fang,
• He-Zhong Jiang and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 998–1007, doi:10.3762/bjoc.19.75

• the correlation of H3-15/H2-6 (Figure 3), which results in ambiguity in the relative configuration assignment of 1. Thus, NMR chemical shift calculations and ECD calculations were used to confirm the relative and absolute configuration of 1. More specifically, NMR calculations were carried out at the

• PCM/mPW1PW91/6-311+G(d,p) [16] level for (7R*,10S*)-1 (1a) and (7S*,10S*)-1 (1b), which are possible diastereomers of 1. The results reveal that 1a has the highest probability score. Next, ECD calculations on (7R,10S)-1 and (7S,10R)-1 were conducted according to the results obtained from NMR

• calculations. The CD spectrum matched well with the calculated ECD spectrum of 1a (Figure 4), revealing the absolute configuration of 1 to be 7R,10S, and it was named aquisinenoid F. Compound 2 was isolated as pale yellow gum, and was assigned the molecular formula C15H24O2 as inferred from the HRESIMS m/z

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

• Brigita Mudráková,
• Renata Marcia de Figueiredo,
• Jean-Marc Campagne and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65

• enolates in high enantiomeric purities. These enolates are reacted with highly electrophilic onium compounds to afford densely substituted acylimidazoles. DFT calculations helped to understand the reactivity of the zinc enolates derived from acylimidazoles and allowed their comparison with metal enolates

• , the configuration at the position C-3 is determined by the chiral ligand L1 and was determined previously as (R) [19]. To gain insight into the reactivity of enolates formed in this transformation, we evaluated properties of Zn enolates by DFT calculations (Figure 2). The corresponding (E) and (Z

• )-enolates were calculated for products 3b and 3d, which possess either an alkyl (ethyl) or an aryl (phenyl) substituent on the stereogenic center. To probe the nature of the imidazole moiety, enolates for products 3g and 3i were also calculated (with a shorter alkyl chain to simplify the calculations

Pyridine C(sp²)–H bond functionalization under transition-metal and rare earth metal catalysis

• Haritha Sindhe,
• Malladi Mounika Reddy,
• Karthikeyan Rajkumar,
• Akshay Kamble,
• Amardeep Singh,
• Anand Kumar and
• Satyasheel Sharma

Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62

• significantly affect the C–H alkylation reaction and the reaction also proceeded well with hydrazones 13 obtained from aliphatic aldehydes or ketones. Based on mechanistic experiments and DFT calculations, the reaction presumably proceeds via a Cu–carbene migratory insertion (Scheme 4b). In the presence of CuI

Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?

• Lukáš Marek,
• Jiří Váňa,
• Jan Svoboda and
• Jiří Hanusek

Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61

• ) level of theory. Quantum calculations (Figure 2) have shown that the reaction pathway that involves an intramolecular proton transfer between the α-carbon and imine nitrogen through TS1 is much more favorable for imidothioate derived from 4-bromoisoquinoline-1,3(2H,4H)-dione (3) and 3-bromooxindole (1

• nitrogen and carbonyl oxygen, generating both nucleophilic and electrophilic centers, i.e., a free amino group and protonated carbonyl group, which is much more prone to nucleophilic attack than a carbonyl group itself. Quantum calculations (see the left side of Figure 2) show that the relative stabilities

• each reaction medium. Unfortunately, the pKaN values of individual thioiminium salts 6a, 10a, 12a, and 15 are not available experimentally, and their exact determination using calculations is also not completely accurate, especially because of the uncertainty of the energy of a solvated proton. However

Non-peptide compounds from Kronopolites svenhedini (Verhoeff) and their antitumor and iNOS inhibitory activities

• Yuan-Nan Yuan,
• Jin-Qiang Li,
• Hong-Bin Fang,
• Shao-Jun Xing,
• Yong-Ming Yan and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 789–799, doi:10.3762/bjoc.19.59

• field (MMFF94) and DFT/TDDFT calculations, were performed for model compounds (3R,4R)-1, (3S,4S)-1, (2S,2″R)-4, (2S,2″S)-4, (2R,2″S)-4, and (2R,2″R)-4 using the Spartan'14 software package and the Gaussian 09 program package. The ECD calculations of the predominant conformers (80%) were conducted using

• DFT calculations at the B3LYP/6-311G(d,p) level of theory. The program SpecDis 1.62 was used to generate the CD spectra [31]. Biological evaluation Antitumor assay Panc02-h7-GP-GFP cells (derived from the transformation of mouse pancreatic cancer cell line Panc02-h7) were maintained at 37 °C in a 5

Synthesis, structure, and properties of switchable cross-conjugated 1,4-diaryl-1,3-butadiynes based on 1,8-bis(dimethylamino)naphthalene

• Semyon V. Tsybulin,
• Ekaterina A. Filatova,
• Alexander F. Pozharskii,
• Valery A. Ozeryanskii and
• Anna V. Gulevskaya

Beilstein J. Org. Chem. 2023, 19, 674–686, doi:10.3762/bjoc.19.49

• proposed for D–π–A systems. This parameter is a good indication for intramolecular charge transfer from the donor to the acceptor moiety in the ground state. In benzene, the qr value is equal to 0. In a fully quinoid ring, the qr was found to be equal to 0.10–0.12. Calculations based on the bond lengths in