A comparative study of DFT calculated and experimental UV/Visible spectra for thirty carboline and carbazole based compounds

Zara, Zeenat; Iqbal, Javed; Ayub, Khurshid; Irfan, Muhammad; Mahmood, Athar; Khera, Rasheed Ahmad; Eliasson, Bertil

doi:10.1016/j.molstruc.2017.07.093

Cited by 56 publications

(35 citation statements)

References 52 publications

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“…All calculations were performed with Gaussian09 program [22]. Trianglimine structures 1, 2, and 3 ( Figure 1) were optimized at cam-B3LYP [23,24] level using 6-311G(d,p) basis set. Subsequently, vibrational frequencies were calculated at the same level of theory to confirm that the obtained structures were true minima.…”

Section: Methodsmentioning

confidence: 99%

Chiroptical Symmetry Analysis of Trianglimines: A Case Study

et al. 2019

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It is well established that chiroptical responses, based on the unique reaction to circularly polarized light by chiral non-racemic systems, are sensitive to the stereochemistry of the featuring systems. This behavior has promoted the use of chiroptical spectroscopies as a mandatory tool in the structure determination of molecules for decades. Recently, the higher sensitivity of chiroptical techniques compared to the conventional UV/Vis absorption and fluorescence spectroscopies or electrochemistry has awakened much interest in the development of chiroptical everyday applications. While chiroptical responses could be predicted by ab initio calculations, large systems calculated at a high level of theory may have an important computational cost; therefore, more intuitive methods are desired to design systems with tailored chiroptical responses. In this regard, the exciton chirality method has been often used in conformationally stable systems incorporating at least two independent chromophores. Taking this method into consideration, in our previous work, we described the chiroptical symmetry analysis (CSA) based on symmetry selection rules. To explore the scope of the CSA, herein we perform the chiroptical symmetry analysis of diverse trianglimines and draw general conclusions to assist on the design of chiroptical systems with high symmetry.

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Section: Methodsmentioning

confidence: 99%

Chiroptical Symmetry Analysis of Trianglimines: A Case Study

et al. 2019

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“…All the calculations were performed using the DFT long-range dispersion-corrected Head-Gordon hybrid functional B97XD [13,[27][28][29], as implemented in Gaussian 16 [30]. The DGDZVP basis set was used to express the wavefunction, since it has been determined to correctly describe the H-Xe elements range [31][32][33][34][35]. Solvent effects were also considered by employing both implicit method and explicit water molecules.…”

Section: Methodsmentioning

confidence: 99%

Effect of the Nucleophile’s Nature on Chloroacetanilide Herbicides Cleavage Reaction Mechanism. A DFT Study

Cuesta

Torres

Rincón

et al. 2021

IJMS

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In this study, the degradation mechanism of chloroacetanilide herbicides in the presence of four different nucleophiles, namely: Br−, I−, HS−, and S2O3−2, was theoretically evaluated using the dispersion-corrected hybrid functional wB97XD and the DGDZVP as a basis set. The comparison of computed activation energies with experimental data shows an excellent correlation (R2 = 0.98 for alachlor and 0.97 for propachlor). The results suggest that the best nucleophiles are those where a sulfur atom performs the nucleophilic attack, whereas the other species are less reactive. Furthermore, it was observed that the different R groups of chloroacetanilide herbicides have a negligible effect on the activation energy of the process. Further insights into the mechanism show that geometrical changes and electronic rearrangements contribute 60% and 40% of the activation energy, respectively. A deeper analysis of the reaction coordinate was conducted, employing the evolution chemical potential, hardness, and electrophilicity index, as well as the electronic flux. The charge analysis shows that the electron density of chlorine increases as the nucleophilic attack occurs. Finally, NBO analysis indicates that the nucleophilic substitution in chloroacetanilides is an asynchronous process with a late transition state for all models except for the case of the iodide attack, which occurs through an early transition state in the reaction.

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“…Molecular geometries in ground state of the single molecules and pre-dimeric configurations were optimized within static DFT electronic structure theory coupled with WB97XD functional (basis set 6,31 G (d,p)). Spectrum calculations utilized TD-DFT approach and WB97XD exchange—correlation functional (basis set 6,31 G (d,p)) [ 11 ].…”

Section: Methodsmentioning

confidence: 99%

Aggregate Formation of Boron-Containing Molecules in Thermal Vacuum Deposited Films

et al. 2021

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The spectral properties of new boron-containing dyes were studied. One-component (pure dyes) and composite “Alq3+dye” thin films were fabricated using the thermal vacuum deposition method. The positions of the transmission spectra maxima in a one-component film are different for different film thicknesses. The best correlation of the maxima positions of the dye transmission spectra in solid and liquid solutions was observed for thicknesses of films close to a few (up to 10) monolayers. On the other hand, the absorption spectra maxima positions of one-component dye films (upper 10 nm) and composite films with high concentration, did not match the corresponding positions of absorption spectra maxima recorded in solutions. Comparison of the absorption spectra in one-component dye films and in solutions indicates the presence of both monomers and their aggregates in one-component films (contrary to solutions where such processes of aggregation do not take place, even at very high concentrations). Simultaneously with aggregation manifestation in the absorption spectra, the intensity of fluorescence of one-component dye films dramatically decreases. A quantum chemical simulation of the possible relative arrangement of two dye molecules indicates that the most possible of the simplest types of aggregates are physical dimers. Films of practical importance (due to efficient energy transfer from host to guest molecules when all singlet excitons are captured) possess a high quantum yield of fluorescence when reaching an impurity concentration of a few percent (aggregation does not take place yet).

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A comparative study of DFT calculated and experimental UV/Visible spectra for thirty carboline and carbazole based compounds

Cited by 56 publications

References 52 publications

Chiroptical Symmetry Analysis of Trianglimines: A Case Study

Chiroptical Symmetry Analysis of Trianglimines: A Case Study

Effect of the Nucleophile’s Nature on Chloroacetanilide Herbicides Cleavage Reaction Mechanism. A DFT Study

Aggregate Formation of Boron-Containing Molecules in Thermal Vacuum Deposited Films

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