HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines

• Luan A. Martinho and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2024, 20, 628–637, doi:10.3762/bjoc.20.55

• protocol showed a lower E-factor by far, which makes it a cleaner and environmentally friendly process. Through the mass intensity parameter, our procedure also showed a lower mass loss compared to the total raw material used to produce a given mass of product. The calculations of these parameters can be

• conditions and Green Chemistry metrics for the GBB reactions under μw and conventional heating conditions.a Supporting Information Supporting Information File 44: Typical experimental procedures, FTIR, NMR and mass spectra of all compounds and GC metrics calculations. Funding The authors thank the

A laterally-fused N-heterocyclic carbene framework from polysubstituted aminoimidazo[5,1-b]oxazol-6-ium salts

• Andrew D. Gillie,
• Matthew G. Wakeling,
• Bethan L. Greene,
• Louise Male and
• Paul W. Davies

Beilstein J. Org. Chem. 2024, 20, 621–627, doi:10.3762/bjoc.20.54

• radius 3.5 Å, mesh spacing 0.10, H atoms removed for calculations. Colour coding represents positioning of steric bulk relative to the centre of the sphere, scale in Å. Use of AImOxAuCl 13 in catalysis. aYields are calculated from the 1H NMR spectra against an internal standard unless otherwise stated

Chemical and biosynthetic potential of Penicillium shentong XL-F41

• Ran Zou,
• Xin Li,
• Xiaochen Chen,
• Yue-Wei Guo and
• Baofu Xu

Beilstein J. Org. Chem. 2024, 20, 597–606, doi:10.3762/bjoc.20.52

• inapplicability of the NOESY experiment. To establish the absolute configuration of compound 1, electron circular dichroism (ECD) calculations were conducted using the time-dependent density functional theory (TDDFT) approach at a B3LYP/6-311G (d,p) (IEFPCM) level (Figure 4). Considering the uncertainty of the

Possible bi-stable structures of pyrenebutanoic acid-linked protein molecules adsorbed on graphene: theoretical study

• Yasuhiro Oishi,
• Motoharu Kitatani and
• Koichi Kusakabe

Beilstein J. Org. Chem. 2024, 20, 570–577, doi:10.3762/bjoc.20.49

• . The results of the nudged elastic band calculations show that the energy difference between the conformations is about 0.35 eV and the activation barrier on the path is about 0.55 eV (Figure 2) [9]. We will refer to the pathway on the potential energy surface with such an activation barrier as an

• . A substitution effect that does not effectively change the potential energy surface is isotopic substitution. In fact, the adiabatic potential surface defined for a hypothetical motion at the absolute zero is not changed by a change in nuclear mass. Even in density functional theory calculations

• , 2, and the conformation at the activation barrier top, respectively. Acknowledgements We are grateful to Prof. H. Ogi, Prof. M. Ohtani, Prof. N. Nakamura, Prof. K. Tanigaki, Prof. S. Hagiwara, and Prof. K. Nakajima for fruitful discussions. The calculations were done at the computer centers of

Synthesis of photo- and ionochromic N-acylated 2-(aminomethylene)benzo[b]thiophene-3(2Н)-ones with a terminal phenanthroline group

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Irina V. Dubonosova,
• Olga Yu. Karlutova,
• Oleg P. Demidov,
• Alexander D. Dubonosov and
• Vladimir A. Bren

Beilstein J. Org. Chem. 2024, 20, 552–560, doi:10.3762/bjoc.20.47

• )methyl)-N-phenylacetamide was used as an actinometer for the quantum yield calculations (φfl = 0.60 ± 0.005) [14][33]. For preparative purposes, a Sweko IP65 led emitter (SUL-S1-20W-230-4000K-WH) was used. Spectral-fluorescent experiments were performed using solutions in acetonitrile or DMSO in quartz

• g/cm3, 17777 reflections measured (9.61° ≤ 2Θ ≤ 152.768°), 4053 unique (Rint = 0.0201, Rσ = 0.0153) that were used in all calculations. The final R1 was 0.0307 (I ≥ 2σ(I)) and wR2 was 0.0813 (all data). Reflections were recorded and unit cell parameters were determined and refined using the

Pseudallenes A and B, new sulfur-containing ovalicin sesquiterpenoid derivatives with antimicrobial activity from the deep-sea cold seep sediment-derived fungus Pseudallescheria boydii CS-793

• Zhen Ying,
• Xiao-Ming Li,
• Sui-Qun Yang,
• Hong-Lei Li,
• Xin Li,
• Bin-Gui Wang and
• Ling-Hong Meng

Beilstein J. Org. Chem. 2024, 20, 470–478, doi:10.3762/bjoc.20.42

• structures were solved by direct methods using the SHELXTL software package [18][19]. All non-hydrogen atoms were refined anisotropically. The H atoms were located by geometrical calculations, and their positions and thermal parameters were fixed during the structure refinement. The absolute structures were

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

• , [10]CPP⊃[5]CPP2+. While the same host–guest complex consisted of neutral CPPs, [10]CPP⊃[5]CPP, was already reported, the cationic complex showed an about 20 times higher association constant in (CDCl2)2 at 25 °C (103 mol L−1). Electrochemical and photophysical analyses and theoretical calculations

• photophysical and electrochemical analyses and DFT calculations. Therefore, this CT is most likely the origin of the increased Ka value. We also discuss the charged double-layer structure, as determined by X-ray crystallographic analysis. Results and Discussion The size-complementary interaction between CPP2

• absorption bands in the visible region and characteristic broad absorption bands extending to the NIR region (≈2000 nm) (Figure 4, black line). According to time-dependent density functional theory (DFT) calculations at the ωB97-XD/6-31G* level of theory, the NIR absorption of the most thermodynamically

Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines

• Eugeny Ivakhnenko,
• Vasily Malay,
• Pavel Knyazev,
• Nikita Merezhko,
• Nadezhda Makarova,
• Oleg Demidov,
• Gennady Borodkin,
• Andrey Starikov and
• Vladimir Minkin

Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34

• –H proton. Therefore, three tautomeric forms are possible for 5 (Scheme 4), one of which, the 7H-tautomer 7b, inevitably adopts a bipolar or biradical structure. According to the data from the DFT calculations performed at the B3LYP/6-311++G(d,p) approximation (Figure S6, Supporting Information File

• reaction products as 12H-quinoxaline[2,3-b]phenoxazines was confirmed through DFT calculations, X-ray crystallography, and NMR spectroscopy. Electronic absorption spectra (Table 2 and Figures 5–7) and electrochemical properties (Table 3) of the heteropentacyclic compounds 4a–h, 5a–c, 6a,b, and 10c revealed

• ). The DFT calculations [32] were performed using the Gaussian 16 program package [33] with the B3LYP functional [34] and the 6-311++G(d,p) basis set. The structures corresponding to minima on the potential energy surface and states with broken symmetry [20] were found through complete optimization of

Unveiling the regioselectivity of rhodium(I)-catalyzed [2 + 2 + 2] cycloaddition reactions for open-cage C₇₀ production

• Cristina Castanyer,
• Anna Pla-Quintana,
• Anna Roglans,
• Albert Artigas and
• Miquel Solà

Beilstein J. Org. Chem. 2024, 20, 272–279, doi:10.3762/bjoc.20.28

• opening. Keywords: cycloadditions; DFT calculations; [70]fullerene; open-cage fullerenes; rhodium; Introduction The discovery of C60 (buckminsterfullerene) in 1985 [1] initiated the search for possible technological applications of fullerenes. Nowadays, applications for these carbon-based molecules have

• group was substituted by a mesyl substituent and BIPHEP was used as a model phosphine ligand instead of Tol-BINAP to reduce the computational cost. The calculations, conducted at the B3LYP-D3/cc-pVTZ-PP(SMD=o-DCB)//B3LYP-D3/cc-pVDZ-PP level (see full computational details in Supporting Information File

• in both cases. This preference was rationalized by means of DFT calculations. Moreover, the photooxidation of one of the C–C double bonds of the new bis(fulleroids) afford open-cage C70 derivatives having a 12-membered ring opening. It is noteworthy to mention that examples of open-cage C70

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

• '-dinitrobenzoylindigo 18b were provided by de Melo and co-workers in 2020 using modern femtosecond spectroscopic techniques as well as TD-DFT calculations [60]. In 1989, Takahashi and co-workers reported an important study of geometry and conformational stability of indigo and its N,N'-disubstituted derivatives [61][62

• along with theoretical calculations [43]. It was found that N-aryl substituents in combination with the polar solvents result in the rapid non-radiative deactivation upon excitation of the initial E-isomer of indigo. At the same time, N-aryl substituents significantly increased the barrier for the

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• also performed theoretical calculations, unveiling that the ring-opening step presented a higher energy barrier compared with the ring-formation step, particularly when the DCV compounds lacked aryl substituents. Subsequently, they successfully isolated the corresponding cyclobutene intermediate 13

• on the fullerene sphere. This was followed by a nucleophilic attack of the fullerene carbanion on one of the cyano groups, ultimately yielding 33. Computational calculations also suggested that the rearrangement was facilitated by the destabilization of the reactant due to steric interactions

• . The absolute configurations of the axially chiral TCBD and DCNQ derivatives were ascertained by a comparative analysis of the experimental CD spectra against the spectra derived from time-dependent density functional theory (TD-DFT) calculations. The axial chirality was stabilized by the steric

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

• pressures and high temperatures [13][14][15]. We aim to shed light in these reaction mechanisms and energy profiles by using complementary methodologies as standard density functional theory (DFT) calculations and first-principles Car–Parrinello molecular dynamics (CPMD) simulations. Firstly, we have

• (periodic calculations using VASP code) by comparing with other more standard procedures (non-periodic calculations using ADF code; see Computational methods for details) when computing the energy profile for the radical cation C60 + C60+. Besides, we computed the profile for the neutral dimerization C60

• -TEM images and movies will provide us a deeper understanding of fullerene coalescence processes in peapods. Computational Methods The Amsterdam Density Functional (ADF) code [21][22] was used for the electronic structure calculations and to optimize reactants, products, intermediates and transition

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

• an exhaust gas line. To align the results using photocatalysts from different batches, an adjustment factor of 2.212 was calculated. The calculations are shown in Supporting Information File 1, Figure S8. Design of experiments A DOE analysis was used to evaluate the effect of four operating

Cycloaddition reactions of heterocyclic azides with 2-cyanoacetamidines as a new route to C,N-diheteroarylcarbamidines

• Pavel S. Silaichev,
• Tetyana V. Beryozkina,
• Vsevolod V. Melekhin,
• Valeriy O. Filimonov,
• Andrey N. Maslivets,
• Vladimir G. Ilkin,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2024, 20, 17–24, doi:10.3762/bjoc.20.3

• (sigma) = 0.0978) which were used in all calculations. The final R1 was 0.0693 (I > 2σ(I)) and wR2 was 0.1849 (all data). The refined twin ratio was 0.6748(18):0.3252(18). The experiment was accomplished on the automated X-ray diffractometer «Xcalibur Ruby» with CCD detector following standard procedures

Studying specificity in protein–glycosaminoglycan recognition with umbrella sampling

• Mateusz Marcisz,
• Sebastian Anila,
• Margrethe Gaardløs,
• Martin Zacharias and
• Sergey A. Samsonov

Beilstein J. Org. Chem. 2023, 19, 1933–1946, doi:10.3762/bjoc.19.144

• analysis of the contacts between protein and GAG molecules established in the course of the simulation. Binding free energy calculations MM/GBSA (molecular mechanics generalized born surface area) model igb = 2 [48] from AMBER20 was used for free energy calculations on the trajectories obtained from RS

• manner more sound for the applied protocol, is to estimate PMF along the reaction coordinate. Such calculations also support the conclusion that the applied protocol did not succeed in returning the system to the original binding pose (Supporting Information File 1, Figures S9–S11). In comparison to the

Beyond n-dopants for organic semiconductors: use of bibenzo[d]imidazoles in UV-promoted dehalogenation reactions of organic halides

• Kan Tang,
• Megan R. Brown,
• Chad Risko,
• Melissa K. Gish,
• Garry Rumbles,
• Phuc H. Pham,
• Oana R. Luca,
• Stephen Barlow and
• Seth R. Marder

Beilstein J. Org. Chem. 2023, 19, 1912–1922, doi:10.3762/bjoc.19.142

• potentials of the halides that can be reduced in this way, quantum-chemical calculations, and steady-state and transient absorption spectroscopy suggest that UV irradiation accelerates the reactions via cleavage of the dimers to the corresponding radical monomers. Keywords: dehalogenation; n-dopant

• weak shoulder at ca. 400 nm (ε400 ≈ 150 M−1 cm−1), whereas (Cyc-DMBI)2 exhibits only a strong feature with a maximum at 327 nm (εmax = 13000 M−1 cm−1). TD-DFT calculations (M06/6-31G(d,p), isolated molecules) qualitatively reproduce the different behavior of the two dimers: for (Cyc-DMBI)2 the S0→S1

• longer-time spectra with Cyc-DMBI• having a blue-shifted absorption relative to N-DMBI•, consistent with the observed features arising from the monomeric radicals. Intersystem crossing (ISC) from the singlet to triplet excited state is also a possibility and TD-DFT calculations suggest that the dimer T1

Controlling the reactivity of La@C₈₂ by reduction: reaction of the La@C₈₂ anion with alkyl halide with high regioselectivity

• Yutaka Maeda,
• Saeka Akita,
• Mitsuaki Suzuki,
• Michio Yamada,
• Takeshi Akasaka,
• Kaoru Kobayashi and
• Shigeru Nagase

Beilstein J. Org. Chem. 2023, 19, 1858–1866, doi:10.3762/bjoc.19.138

• analysis of the single-bonded adduct 3a revealed the addition site of the p-methoxybenzyl group on La@C2v-C82. Theoretical calculations indicated that the addition site carbons in neutral La@C2v-C82 have high spin density, whereas those in the La@C2v-C82 anion do not have high charge densities. Thus, the

• @Ih-C80]2− = −1.62 V vs Fc+/Fc; C602− = −1.50 V vs Fc+/Fc)). The different reactivity of [M3N@Ih-C80]2− was explained by theoretical calculations. The charge density of the highest occupied molecular orbital (HOMO) was more highly localized on the fullerene cage for [Lu3N@Ih-C80]2−, whereas it was

• 2299232 (for 3a) contains the supplementary crystallographic data for this study. This data was provided free of charge by the joint Cambridge Crystallographic Data Centre and Fachinformationszentrum Karlsruhe Access Structures Service. Theoretical calculations POAV (θσπ−90º) and charge densities values

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