Systematic study on the TD-DFT calculated electronic circular dichroism spectra of chiral aromatic nitro compounds: A comparison of B3LYP and CAM-B3LYP

Komjáti, Balázs; Urai, Ákos; Hosztafi, Sándor; Kökösi, József; Kováts, Benjámin; Nagy, József; Horváth, Péter

doi:10.1016/j.saa.2015.11.002

Cited by 50 publications

(20 citation statements)

References 34 publications

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“…The former yielded a retained all-trans conformation that was about 2 kcal/mol lower in energy than the all-cis conformation. For evaluating the excited states we chose the CAM-B3LYP 54 long-range exchange correlation functional due to its efficacy in describing chiral aromatic molecules 55 and the def2-TZVPPD polarized basis set. 56 Excited state calculations were performed both in vacuum and using the IEF-PCM continuum solvation model for chloroform.…”

Section: Resultsmentioning

confidence: 99%

Theory of Apparent Circular Dichroism Reveals the Origin of Inverted and Noninverted Chiroptical Response under Sample Flipping

2021

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Circular dichroism (CD) finds widespread application as an optical probe for the structure of molecules and supramolecular assemblies. Its underlying chiral light−matter interactions effectively couple between photonic spin states and select quantum-mechanical degrees of freedom in a sample, implying an intricate connection with photon-to-matter quantum transduction. However, effective transduction implementations likely require interactions that are antisymmetric with respect to the direction of light propagation through the sample, yielding an inversion of the chiroptical response upon sample flipping, which is uncommon for CD. Recent experiments on organic thin films have demonstrated such chiroptical behavior, which was attributed to "apparent CD" resulting from an interference between the sample's linear birefringence and linear dichroism. However, a theory connecting the underlying optical selection rules to the microscopic electronic structure of the constituent molecules remains to be formulated. Here, we present such a theory based on a combination of Mueller calculus and a Lorentz oscillator model. The theory reaches good agreement with experimental CD spectra and allows for establishing the (supra)molecular design rules for maximizing or minimizing this chiroptical effect. It furthermore highlights that, in addition to antisymmetrically, it can manifest symmetrically such that no chiroptical response inversion occurs, which is a consequence of a helical stacking of molecules in the light propagation direction.

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Section: Resultsmentioning

confidence: 99%

Theory of Apparent Circular Dichroism Reveals the Origin of Inverted and Noninverted Chiroptical Response under Sample Flipping

2021

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“…Although our previous joint experimental and computational studies demonstrated that the hybrid functional PBE0 was capable of accurately representing the excited properties of many Ir(III) complexes, , PBE0 failed in reproducing the correct trends for the complexes studied in this work, especially for complexes containing the nitro substituent. It has been discussed in the literature that long-range corrected functionals, such as CAM-B3LYP, more accurately describe the localization/delocalization properties of charge transfer states in the donor–acceptor molecules than hybrid functionals, despite the overall overestimation of the excited energies. , As such, we chose CAM-B3LYP for our calculations, while we applied a constant shift of −0.82 eV to correct the blue shift and align the calculated absorption spectra with the experimental spectra. To construct the absorption spectra, each optical transition obtained from TDDFT calculations was broadened by the Gaussian function with a width of σ = 0.08 eV, which well reproduces the thermal broadening of the experimental spectra.…”

Section: Methodsmentioning

confidence: 99%

Neutral Cyclometalated Iridium(III) Complexes Bearing Substituted N-Heterocyclic Carbene (NHC) Ligands for High-Performance Yellow OLED Application

et al. 2019

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The synthesis, crystal structure, and photophysics of a series of neutral cyclometalated iridium(III) complexes bearing substituted N-heterocyclic carbene (NHC) ancillary ligands ((C ∧ N) 2 Ir(R-NHC), where C ∧ N and NHC refer to the cyclometalating ligand benzo[h]quinoline and 1-phenylbenzimidazole, respectively) are reported. The NHC ligands were substituted with electron-withdrawing or -donating groups on C4′ of the phenyl ring (R = NO 2 (Ir1), CN (Ir2), H (Ir3), OCH 3 (Ir4), N(CH 3 ) 2 (Ir5)) or C5 of the benzimidazole ring (R = NO 2 (Ir6), N(CH 3 ) 2 (Ir7)). The configuration of Ir1 was confirmed by a single-crystal X-ray diffraction analysis. The ground-and excited-state properties of Ir1− Ir7 were investigated by both spectroscopic methods and time-dependent density functional theory (TDDFT) calculations. All complexes possessed moderately strong structureless absorption bands at ca. 440 nm that originated from the C ∧ N ligand based 1 π,π*/ 1 CT (charge transfer)/ 1 d,d transitions and very weak spin−forbidden 3 MLCT (metal-to-ligand charge transfer)/ 3 LLCT (ligand-to-ligand charge transfer) transitions beyond 500 nm. Electron-withdrawing substituents caused a slight blue shift of the 1 π,π*/ 1 CT/ 1 d,d band, while electron-donating substituents induced a red shift of this band in comparison to the unsubstituted complex Ir3. Except for the weakly emissive nitro-substituted complexes Ir1 and Ir6 that had much shorter lifetimes (≤160 ns), the other complexes are highly emissive in organic solutions with microsecond lifetimes at ca. 540−550 nm at room temperature, with the emitting states being predominantly assigned to 3 π,π*/ 3 MLCT states. Although the effect of the substituents on the emission energy was insignificant, the effects on the emission quantum yields and lifetimes were drastic. All complexes also exhibited broad triplet excited-state absorption at 460−700 nm with similar spectral features, indicating the similar parentage of the lowest triplet excited states. The highly emissive Ir2 was used as a dopant for organic light-emitting diode (OLED) fabrication. The device displayed a yellow emission with a maximum current efficiency (η c ) of 71.29 cd A −1 , a maximum luminance (L max ) of 32747 cd m −2 , and a maximum external quantum efficiency (EQE) of 20.6%. These results suggest the potential of utilizing this type of neutral Ir(III) complex as an efficient yellow phosphorescent emitter.

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“…This functional was selected because it describes the high accuracy systems, including corrections for a better description of long-range interactions. 40,41 A theoretical polar environment was simulated by means of the integral equation formalism in the implicit solvation method of the polarizable continuous model (IEFPCM) implicit solvation method, 42 using acetonitrile, dichloromethane and dimethyl sulfoxide (DMSO) as solvents to emulate possible intermolecular interactions around the analyzed molecules. The basis set used for developing of all the calculations was the double zeta 6-311G(d,p) for all atoms.…”

Section: Calculationsmentioning

confidence: 99%

Theoretical and Experimental Spectroscopic Study on 2-Chloro-3-(substitutedphenylamino)-1,4-naphthoquinone Derivatives

Dias¹,

Campos²,

Moraes³

et al. 2023

J. Braz. Chem. Soc.

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The 1,4-naphthoquinones are an important group of compounds intensively studied because of their wide range of biological activities. Four 2-chloro-3-(substituted-phenylamino)- 1,4‑naphthoquinone derivatives were synthesized, and the vibrational modes of these molecules were assigned using Raman and Fourier transform infrared spectroscopy (FTIR) techniques. In addition, X-ray studies were performed for one of these derivatives. Density functional theory (DFT) calculations were also developed for these compounds and presented. In summary, the results obtained from these studies can assess chemical changes in the structures of functionalized quinones and the discovery of candidate biologically active compounds.

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Systematic study on the TD-DFT calculated electronic circular dichroism spectra of chiral aromatic nitro compounds: A comparison of B3LYP and CAM-B3LYP

Cited by 50 publications

References 34 publications

Theory of Apparent Circular Dichroism Reveals the Origin of Inverted and Noninverted Chiroptical Response under Sample Flipping

Theory of Apparent Circular Dichroism Reveals the Origin of Inverted and Noninverted Chiroptical Response under Sample Flipping

Neutral Cyclometalated Iridium(III) Complexes Bearing Substituted N-Heterocyclic Carbene (NHC) Ligands for High-Performance Yellow OLED Application

Theoretical and Experimental Spectroscopic Study on 2-Chloro-3-(substitutedphenylamino)-1,4-naphthoquinone Derivatives

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