Models of necessity

• Timothy Clark and
• Martin G. Hicks

Beilstein J. Org. Chem. 2020, 16, 1649–1661, doi:10.3762/bjoc.16.137

• , which is difficult to reconcile with requirement 2 above. A possible solution would be to use computationally very efficient quantum mechanics such as, for instance, semiempirical molecular-orbital theory or tight-binding density-functional theory. As outlined above, these techniques are fast enough to

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

• measurements, TRPL spectroscopy, and density functional theory (DFT) calculations. They found that the HER efficiency correlated to the excited state lifetime and exciton binding energy. The FSO-BP and FSO-FSz hindered the charge transfer and mobility due to the phenyl–phenyl dihedral angle or sharp bends in

In silico rationalisation of selectivity and reactivity in Pd-catalysed C–H activation reactions

• Liwei Cao,
• Mikhail Kabeshov,
• Steven V. Ley and
• Alexei A. Lapkin

Beilstein J. Org. Chem. 2020, 16, 1465–1475, doi:10.3762/bjoc.16.122

• automated reaction planning, as well as a starting point for microkinetic modelling. Keywords: C–H activation; density functional theory; reaction prediction; Introduction Periodically, our knowledge of chemistry is enriched with new transformations that provide significant breakthroughs by enabling new

• the mechanistic models based on accurate quantum chemical methods, such as the density functional theory (DFT) methods, decreases. Automation of DFT, as well as using results of DFT to develop less expensive predictive models, are the two approaches that may offer the alternatives to the fully data

• transition metal coordination sphere; the energy of a new M–C bond formed and the thermodynamic stability of organometallic product. With new developments in computational chemistry, mechanistic studies using density functional theory (DFT) provide valuable insights into the reactivity of organometallic

Development of fluorinated benzils and bisbenzils as room-temperature phosphorescent molecules

• Shigeyuki Yamada,
• Takuya Higashida,
• Yizhou Wang,
• Masato Morita,
• Takuya Hosokai,
• Kaveendra Maduwantha,
• Kaveenga Rasika Koswattage and
• Tsutomu Konno

Beilstein J. Org. Chem. 2020, 16, 1154–1162, doi:10.3762/bjoc.16.102

• -deficient fluorinated aromatic ring. To confirm the electron-withdrawing effect of this fluorinated aromatic ring, the electronic charge at the adjacent C≡C bond was calculated by density functional theory (DFT) using the Gaussian 16 (Revision B.01) software package [35]. As typical examples, the molecular

• derivatives previously developed by our group and (B) phosphorescent molecular structures intended for this work. Mulliken charge distributions of fluorinated 1a and nonfluorinated 1c obtained from density functional theory calculations [CAM-B3LYP/6-31+G(d) level]. Absorption and photoluminescence (PL

• molecular orbitals (isosurface value: 0.04 a.u.) involved in vertical electronic transitions in 2a and 3a calculated using density functional theory (DFT) and time-dependent DFT at the CAM-B3LYP/6-31+G(d) level (HOMO: highest occupied molecular orbital, LUMO: lowest unoccupied molecular orbital). Synthetic

Aryl-substituted acridanes as hosts for TADF-based OLEDs

• Naveen Masimukku,
• Dalius Gudeika,
• Oleksandr Bezvikonnyi,
• Ihor Syvorotka,
• Rasa Keruckiene,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 989–1000, doi:10.3762/bjoc.16.88

• . Theoretical calculations The optimized structures of 3–6 were obtained by density functional theory (DFT) calculations at the B3LYP/6-31G(d,p) level of theory (Figure 1). The dihedral angles between the acridanyl and phenyl moieties in compound 3 (37.0 and 36.3°) are comparable with the dihedral angles

Cation-induced ring-opening and oxidation reaction of photoreluctant spirooxazine–quinolizinium conjugates

• Phil M. Pithan,
• Sören Steup and
• Heiko Ihmels

Beilstein J. Org. Chem. 2020, 16, 904–916, doi:10.3762/bjoc.16.82

• discussed in the literature whether metal cations are coordinated in a monodentate fashion to the phenolate oxygen atom or rather in a bidentate fashion both to the phenolate oxygen and the imine nitrogen atoms of the open merocyanine form [25][28]. Furthermore, density functional theory (DFT) calculations

Direct borylation of terrylene and quaterrylene

• Haruka Kano,
• Keiji Uehara,
• Kyohei Matsuo,
• Hironobu Hayashi,
• Hiroko Yamada and
• Naoki Aratani

Beilstein J. Org. Chem. 2020, 16, 621–627, doi:10.3762/bjoc.16.58

• fluorescence at 576 nm with a quantum yield of ΦF = 0.86 at 298 K (Figure 3). Both peaks are slightly red-shifted relative to those of intact terrylene (λabs = 560 nm and λem = 571 nm with ΦF = 0.82 in toluene). We employed density functional theory (DFT) and time-dependent (TD)-DFT calculations, both of them

Regioselectively α- and β-alkynylated BODIPY dyes via gold(I)-catalyzed direct C–H functionalization and their photophysical properties

• Takahide Shimada,
• Shigeki Mori,
• Masatoshi Ishida and
• Hiroyuki Furuta

Beilstein J. Org. Chem. 2020, 16, 587–595, doi:10.3762/bjoc.16.53

• , density functional theory (DFT) calculations were performed at the B3LYP/6-31G(d) level of theory. The a2-symmetry of the HOMOs and b2-symmetry of the LUMOs of each, the α- and β-ethynyl-substituted BODIPYs are almost identical to those of the unsubstituted compound 1a (Figure S24, Supporting Information

Six-fold C–H borylation of hexa-peri-hexabenzocoronene

• Mai Nagase,
• Kenta Kato,
• Akiko Yagi,
• Yasutomo Segawa and
• Kenichiro Itami

Beilstein J. Org. Chem. 2020, 16, 391–397, doi:10.3762/bjoc.16.37

• -catalyzed six-fold C–H borylation of HBC was successfully achieved by screening solvents. The crystal structure of hexaborylated HBC was confirmed via X-ray crystallography. Optoelectronic properties of the thus-obtained hexaborylated HBC were analyzed with the support of density functional theory

• hexaborylated HBC 1. The structure of thus-obtained 1 was confirmed by X-ray crystallography, and the electronic effects of the boryl groups were investigated through optoelectronic measurements and density functional theory (DFT) calculations. Results and Discussion We have examined the conditions for C–H

p-Pyridinyl oxime carbamates: synthesis, DNA binding, DNA photocleaving activity and theoretical photodegradation studies

• Panagiotis S. Gritzapis,
• Panayiotis C. Varras,
• Nikolaos-Panagiotis Andreou,
• Katerina R. Katsani,
• Konstantinos Dafnopoulos,
• George Psomas,
• Zisis V. Peitsinis,
• Alexandros E. Koumbis and
• Konstantina C. Fylaktakidou

Beilstein J. Org. Chem. 2020, 16, 337–350, doi:10.3762/bjoc.16.33

• factor of 1.43 [11]. Theoretical calculations Calculations for the photodegradation of carbamates The structures, properties and the basic photochemistry of compounds 11 and 12 was studied using the density functional theory (DFT) method [86][87][88][89] and the functional B3PW91 along with the 6-31 G(d

The reaction of arylmethyl isocyanides and arylmethylamines with xanthate esters: a facile and unexpected synthesis of carbamothioates

• Narasimhamurthy Rajeev,
• Toreshettahally R. Swaroop,
• Ahmad I. Alrawashdeh,
• Shofiur Rahman,
• Abdullah Alodhayb,
• Seegehalli M. Anil,
• Kuppalli R. Kiran,
• Chandra,
• Paris E. Georghiou,
• Kanchugarakoppal S. Rangappa and
• Maralinganadoddi P. Sadashiva

Beilstein J. Org. Chem. 2020, 16, 159–167, doi:10.3762/bjoc.16.18

• reactions, a mechanism is proposed in which the key steps are supported by quantum chemical calculations. Keywords: benzylamines; carbamothioates; density functional theory; intrinsic reaction coordinate analysis; isocyanides; sodium hydride; xanthate esters; Introduction Carbamothioates (thiocarbamates

• , however, carbamothioates 4a–l were instead obtained in 76–88% yield (Scheme 1). Herein, we report on this intriguing finding and show several examples, including a single crystal X-ray structure of one of the products so obtained. A plausible mechanism to explain the reaction using density functional

• theory (DFT) analysis is also presented in this article. Results and Discussion Synthesis At the onset of our study, the reaction between O-benzyl S-methyl dithiocarbonate (1a) and benzyl isocyanide was conducted in the presence of sodium hydride in DMF. The product, obtained in 85% yield after 10 min

Synthesis and characterization of bis(4-amino-2-bromo-6-methoxy)azobenzene derivatives

• David Martínez-López,
• Amirhossein Babalhavaeji,
• Diego Sampedro and
• G. Andrew Woolley

Beilstein J. Org. Chem. 2019, 15, 3000–3008, doi:10.3762/bjoc.15.296

• of intramolecular H-bond formation, we wished to retain at least one methoxy group. To reduce the rate of thermal reversion, only derivatives with substituents in all four ortho-positions were considered. Time-dependent density functional theory (TD-DFT) calculations were used to predict the

• absorption wavelengths of possible derivatives. Based on these considerations, we carried out the synthesis and photochemical characterization of compounds 4 and 5. Results and Discussion Computational chemistry Calculations were performed using density functional theory (DFT) methods (B3LYP/6-31+G**) to

Pigmentosins from Gibellula sp. as antibiofilm agents and a new glycosylated asperfuran from Cordyceps javanica

• Soleiman E. Helaly,
• Wilawan Kuephadungphan,
• Patima Phainuphong,
• Mahmoud A. A. Ibrahim,
• Kanoksri Tasanathai,
• Suchada Mongkolsamrit,
• Janet Jennifer Luangsa-ard,
• Souwalak Phongpaichit,
• Vatcharin Rukachaisirikul and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2968–2981, doi:10.3762/bjoc.15.293

• ) were not elucidated previously. Therefore, electronic circular dichroism (ECD) measurements combined with time-dependent density functional theory (TDDFT) calculations of ECD data of compound 1 in MeOH at the B3LYP/6-311+G* level of theory were carried out. The CD spectrum of 1 showed strong Cotton

Synthesis and optoelectronic properties of benzoquinone-based donor–acceptor compounds

• Daniel R. Sutherland,
• Nidhi Sharma,
• Georgina M. Rosair,
• Ifor D. W. Samuel,
• Ai-Lan Lee and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2019, 15, 2914–2921, doi:10.3762/bjoc.15.285

• carbazoles with respect to the bridging benzene of ca. 44° in both 3 and 4 (Figure 2). Theoretical properties Density functional theory (DFT) calculations were performed in the gas phase to assess the electronic structures of 2–5 (see Supporting Information File 1 for details). The S1 and T1 excited states

• were calculated from the optimized ground-state structure using the Tamm Dancoff approximation (TDA) to time-dependent density functional theory (TD-DFT) [30][31]. In all derivatives, the LUMO is mainly localized on the strongly electron-accepting BQ moiety (Figure 3). The HOMO is mainly located on the

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

• from the adsorption branches using nonlocal density functional theory (NLDFT) methods. P2–P5 exhibited narrow pore size distribution in the micropore scopes (<2 nm), while P1 showed a wide pore size distribution. The surface areas of P1–P5 ranged from 350 to 769 m2 g−1 (Table 2). The lowest specific

A combinatorial approach to improving the performance of azoarene photoswitches

• Joaquin Calbo,
• Aditya R. Thawani,
• Rosina S. L. Gibson,
• Andrew J. P. White and
• Matthew J. Fuchter

Beilstein J. Org. Chem. 2019, 15, 2753–2764, doi:10.3762/bjoc.15.266

• performance: o-F [13][14], o-Cl [8][29][30], o-OMe [10][29][31], or o-Pyr [32]. For the sake of comparison, both mono- and di-ortho-substitutions were considered. Theoretical half-lives (t1/2) were calculated within the density functional theory (DFT) framework, according to the protocol reported in our prior

• ground state geometries of both Z- and E-isomers were computed under the time-dependent density functional theory (TDDFT) approach [41][42]. The 20 lowest-lying singlet excited states were calculated in all conformers at the TD-PBE0/6-31G** level of theory in the gas phase. Solvent effects in

Acid-catalyzed rearrangements in arenes: interconversions in the quaterphenyl series

• Sarah L. Skraba-Joiner,
• Carter J. Holt and
• Richard P. Johnson

Beilstein J. Org. Chem. 2019, 15, 2655–2663, doi:10.3762/bjoc.15.258

• . This supports thermodynamic control based on carbocation energies. Keywords: arenium ion; carbocation; density functional theory; microwave reaction; rearrangement; superacid; Introduction Carbocations are enigmatic reactive intermediates of enduring importance in chemistry. No other reactive species

Plasma membrane imaging with a fluorescent benzothiadiazole derivative

• Pedro H. P. R. Carvalho,
• Jose R. Correa,
• Karen L. R. Paiva,
• Daniel F. S. Machado,
• Jackson D. Scholten and
• Brenno A. D. Neto

Beilstein J. Org. Chem. 2019, 15, 2644–2654, doi:10.3762/bjoc.15.257

• density functional theory (TD-DFT). In practice, when applying DFT calculations, there is no “universal” exchange correlation functional (XCF), thus the performance of different XCFs in simulating the absorption spectra of BTD-4APTEG had to be assessed. We aimed at describing the maxima absorption peak

Experimental and computational electrochemistry of quinazolinespirohexadienone molecular switches – differential electrochromic vs photochromic behavior

• Eric W. Webb,
• Jonathan P. Moerdyk,
• Kyndra B. Sluiter,
• Benjamin J. Pollock,
• Amy L. Speelman,
• Eugene J. Lynch,
• William F. Polik and
• Jason G. Gillmore

Beilstein J. Org. Chem. 2019, 15, 2473–2485, doi:10.3762/bjoc.15.240

• cyclic voltammetry and 1H NMR analyses, in concert with computational modeling. These results are compared to those for the symmetric parent PSHD, which due to symmetry possesses only a single possible regioisomer upon either electrochemical or photochemical ring-opening. Density functional theory

• calculations of bond lengths, bond orders, and molecular orbitals allow the rationalization of this differential photochromic vs electrochromic behavior of the QSHDs. Keywords: cyclic voltammetry; density functional theory; heterocycles; molecular switches; photochromic photooxidants; spirocycles

• functional theory (DFT) calculated molecular orbitals (MOs, e.g., Figure 6 and Supporting Information File 1) indicate that the LUMO (MO 106 for 3a) lies exclusively on the dienone moiety both in 1b and in the quinazolinespirohexadienone photochromes 3a,b. Thus, the dienone moiety is likely the electrophore

Reversible switching of arylazopyrazole within a metal–organic cage

• Anton I. Hanopolskyi,
• Soumen De,
• Michał J. Białek,
• Yael Diskin-Posner,
• Liat Avram,
• Moran Feller and
• Rafal Klajn

Beilstein J. Org. Chem. 2019, 15, 2398–2407, doi:10.3762/bjoc.15.232

• -ray diffraction. To obtain hints about the packing of Z-1 within 2, we therefore performed density functional theory (DFT) calculations. Compared with the complex before photoisomerization, the cage in (Z-1)2 is severely distorted (Figure 5; see also Supporting Information File 3), assuming a bowl

Excited state dynamics for visible-light sensitization of a photochromic benzil-subsituted phenoxyl-imidazolyl radical complex

• Yoichi Kobayashi,
• Yukie Mamiya,
• Katsuya Mutoh,
• Hikaru Sotome,
• Masafumi Koga,
• Hiroshi Miyasaka and
• Jiro Abe

Beilstein J. Org. Chem. 2019, 15, 2369–2379, doi:10.3762/bjoc.15.229

• chromatography (HPLC), and each isomer was characterized by steady-state absorption spectra and time-dependent density functional theory (TDDFT) calculations as shown below. Figure 1 shows the steady-state absorption spectra of the two isomers of Benzil-PIC and PIC in benzene at 298 K. While the absorption of

Current understanding and biotechnological application of the bacterial diterpene synthase CotB2

• Ronja Driller,
• Daniel Garbe,
• Norbert Mehlmer,
• Monika Fuchs,
• Keren Raz,
• Dan Thomas Major,
• Thomas Brück and
• Bernhard Loll

Beilstein J. Org. Chem. 2019, 15, 2355–2368, doi:10.3762/bjoc.15.228

• rearrangement. Hong and Tantillo performed the first theoretical study of the reaction mechanism in CotB2 via gas phase density functional theory (DFT) calculations [33]. Simultaneously, Sato et al. also studied the CotB2 reaction mechanism in the gas phase using DFT, combined with experimental deuterium

• ], density functional theory calculations [33] as well as QM/MM simulations [37]. Variants of CotB2 open the route to a novel product portfolio with altered cyclic carbon skeletons, which can be converted into bioactive compounds by chemo-enzymatic methodologies. Modification descriptions are composed

Aggregation-induced emission effect on turn-off fluorescent switching of a photochromic diarylethene

• Luna Kono,
• Yuma Nakagawa,
• Ayako Fujimoto,
• Ryo Nishimura,
• Yohei Hattori,
• Toshiki Mutai,
• Nobuhiro Yasuda,
• Kenichi Koizumi,
• Satoshi Yokojima,
• Shinichiro Nakamura and
• Kingo Uchida

Beilstein J. Org. Chem. 2019, 15, 2204–2212, doi:10.3762/bjoc.15.217

• functional theory (DFT) and time-dependent DFT (TDDFT). The excitation wavelengths as well as the emission wavelength qualitatively agrees with the experimental results. Since compound 1 consists of a diarylethene moiety and an imidazo[1,2-a]pyridine moiety, the characteristic of 1 has the combination of

• decreased gradually upon UV light irradiation accompanied with the formation of 1c, because of excitation energy transfer from the ESIPT moiety to the closed-ring isomer (Figure 5) [4]. The wavelengths of absorption (Table 3) and fluorescence (Table 4) were obtained computationally by using density

Azologization and repurposing of a hetero-stilbene-based kinase inhibitor: towards the design of photoswitchable sirtuin inhibitors

• Christoph W. Grathwol,
• Nathalie Wössner,
• Sören Swyter,
• Adam C. Smith,
• Enrico Tapavicza,
• Robert K. Hofstetter,
• Anja Bodtke,
• Manfred Jung and
• Andreas Link

Beilstein J. Org. Chem. 2019, 15, 2170–2183, doi:10.3762/bjoc.15.214

• functional theory (DFT) to optimize the ground state equilibrium structures of (E)-2b, (Z)-2b, 8a and 8b, and used time-dependent DFT (TDDFT) and high-level correlated methods to obtain UV–vis absorption energies and oscillator strengths. To obtain the simulated absorption spectrum and λmax values

• ortho methyl groups in 2f, intramolecular photocyclization could be prevented. To verify the hypothetical structures derived from irradiation of 2b, we carried out quantum chemical calculations of the double bond isomers (E)-2b and (Z)-2b as well as the oxidized compounds 8a and 8b. We used density

Bipolenins K–N: New sesquiterpenoids from the fungal plant pathogen Bipolaris sorokiniana

• Chin-Soon Phan,
• Hang Li,
• Simon Kessler,
• Peter S. Solomon,
• Andrew M. Piggott and
• Yit-Heng Chooi

Beilstein J. Org. Chem. 2019, 15, 2020–2028, doi:10.3762/bjoc.15.198

• -13 were α-oriented. The absolute configuration of 1 was determined to be 1R,3R,6S,7R,13S by comparison of the experimental electronic circular dichroism (ECD) spectrum with time-dependent density functional theory (TDDFT)-calculated ECD spectra of the two possible enantiomers of 1 (Figure 4