Green Synthesis of Triazole-Based Chemosensors and their Efficacy Towards Mercury Sensing

2020 ◽  
Vol 16 (6) ◽  
pp. 738-743 ◽  
Author(s):  
Poonam Rani ◽  
Kashmiri Lal ◽  
Vikas D. Ghule ◽  
Rahul Shrivastava
Keyword(s):  
Detection Limit ◽  
Metal Ions ◽  
Density Functional ◽  
Organic Molecules ◽  
Functional Theory ◽  
Small Organic Molecules ◽  
Industrial Activities ◽  
Binding Stoichiometry ◽  
Visible Spectra ◽  
Uv Visible

Background: The synthesis of small organic molecules based Hg2+ ions receptors have gained considerable attention because it is one of the most prevalent toxic metals which is continuously discharged into the environment by different natural and industrial activities. 1,4-Disubstituted 1,2,3-triazoles have been reported as good chemosensors for the detection of various metal ions including Hg2+ ions. Methods: The synthesis of 1,2,3-triazoles (4a-4c) was achieved by Cu(I)-catalyzed azide-alkyne cycloaddition, and their binding affinity towards various metal ions and anions were studied by UVVisible titration experiments. The perchlorate salts of metal ions and tetrabutylammonium salts of anions were utilized for the UV-Visible experiments. DFT studies were performed to understand the binding and mechanism on the sensing of 4a toward Hg2+ using the B3LYP/6-311G(d,p) method for 4a and B3LYP/LANL2DZ for 4a-Hg2+ species on the Gaussian 09W program. Results: The UV-visible experiments indicated that the compounds 4a-4c show a selective response towards Hg2+ ion in UV-Visible spectra, while other ions did not display such changes in the absorption spectra. The binding stoichiometry was evaluated by Job’s plot which indicated the 1:1 binding stoichiometry between receptors (4a-4c) and Hg2+ ion. The detection limit of 4a, 4b and 4c for the Hg2+ ions was found to be 29.1 nM, 3.5 μM and 1.34 μM, respectively. Conclusion: Some 1,2,3-triazole derivatives were synthesized (4a-4c) exhibiting high selectively and sensitivity towards Hg2+ ions in preference to other ions. Compound 4a has a low detection limit of 29.1 nM and the binding constant of 2.3×106 M-1. Similarly, 4b and 4c also showed selective sensing towards Hg2+ ions in the μM range. The observed experimental results were corroborated by density functional theory (DFT) calculations.

scholarly journals Changes in CO2 Adsorption Affinity Related to Ni Doping in FeS Surfaces: A DFT-D3 Study

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 486
Author(s):  
Aleksandar Zivković ◽  
Michiel Somers ◽  
Eloi Camprubi ◽  
Helen E. King ◽  
Mariette Wolthers ◽  
...  
Keyword(s):  
Density Functional ◽  
Organic Molecules ◽  
Ni Doping ◽  
Functional Theory ◽  
Small Organic Molecules ◽  
Adsorption Affinity ◽  
The Origin Of Life ◽  
Carbon Dioxide Co2 ◽  
Partial Desorption ◽  
Good Agreement

Metal sulphides constitute cheap, naturally abundant, and environmentally friendly materials for energy storage applications and chemistry. In particular, iron (II) monosulphide (FeS, mackinawite) is a material of relevance in theories of the origin of life and for heterogenous catalytic applications in the conversion of carbon dioxide (CO2) towards small organic molecules. In natural mackinawite, Fe is often substituted by other metals, however, little is known about how such substitutions alter the chemical activity of the material. Herein, the effect of Ni doping on the structural, electronic, and catalytic properties of FeS surfaces is explored via dispersion-corrected density functional theory simulations. Substitutional Ni dopants, introduced on the Fe site, are readily incorporated into the pristine matrix of FeS, in good agreement with experimental measurements. The CO2 molecule was found to undergo deactivation and partial desorption from the doped surfaces, mainly at the Ni site when compared to undoped FeS surfaces. This behaviour is attributed to the energetically lowered d-band centre position of the doped surface, as a consequence of the increased number of paired electrons originating from the Ni dopant. The reaction and activation energies of CO2 dissociation atop the doped surfaces were found to be increased when compared to pristine surfaces, thus helping to further elucidate the role Ni could have played in the reactivity of FeS. It is expected that Ni doping in other Fe-sulphides may have a similar effect, limiting the catalytic activity of these phases when this dopant is present at their surfaces.

scholarly journals Investigating Functional Performance and Substituent Effect in Modelling Molecular Structure, UV-Visible Spectra and Optical Properties of D-π-A Conjugated Organic Dye Molecules: A DFT and TD-DFT Study.

2021 ◽  
Author(s):  
Garima Chanana ◽  
Kriti Batra
Keyword(s):  
Molecular Structure ◽  
Density Functional Theory ◽  
Density Functional ◽  
Organic Dye ◽  
Dye Molecules ◽  
Functional Theory ◽  
Donor And Acceptor ◽  
Visible Spectra ◽  
Td Dft ◽  
Uv Visible

Abstract The molecular structure, UV-Visible spectra, and optical properties of D-π-A conjugated organic dye molecules (Disperse Red 1 (DR1) and Disperse Red 73 (DR73)) were analyzed using Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) and compared with Azobenzene molecule to study the effect of Donor and Acceptor substituents on the molecular properties. The performance of DFT functionals is investigated using B3LYP hybrid functional and three long-range corrected functionals (CAM-B3LYP, LC-ωPBE, and ωB97XD) in conjunction with 6-31G(d,p) basis set. Using TD-DFT, we calculate the vertical excitation energies and transition dipole moment values for 100 excited states. These values were further utilized to calculate frequency dependent polarizability under Sum-Over-States (SOS) formalism and refractive index of these molecular systems. We observe that for Azobenzene and DR1 molecules, ωB97XD predicted wavelengths corresponding to peak absorbance closest to the experimental results, while for DR73 molecule, B3LYP gave better prediction. Large polarizability response is also observed for these molecules (DR1 and DR73) in comparison to parent Azobenzene structure due to charge transfer between donor and acceptor groups. For DR1 and DR73 molecules, αxx component of polarizability dominates in contrast to azobenzene where αzz dominates. The HOMO→LUMO transition during excitation contributes to the peak molecular response in simulated UV-Visible spectra. The high polarizability response of selected D-π-A conjugated molecules in comparison to parent molecule suggests that these molecules are promising candidates for tailor-made photonic and optoelectronic device development

scholarly journals Study of Substituent Effect on Properties of Platinum(II) Porphyrin Semiconductor Using Density Functional Theory

2018 ◽  
Vol 18 (4) ◽  
pp. 742
Author(s):  
Harno Dwi Pranowo ◽  
Fadjar Mulya ◽  
Hafiz Aji Aziz ◽  
Grisani Ambar Santoso
Keyword(s):  
Substituent Effect ◽  
Density Functional ◽  
Geometry Optimization ◽  
Dft Method ◽  
Band Gap Energy ◽  
Functional Theory ◽  
Substituent Group ◽  
Partial Charges ◽  
Visible Spectra ◽  
Uv Visible

Study of substituent effect on properties of platinum(II) porphyrin had been performed using DFT method. The aim of the study is to investigate the effect of substituent group on the electronic and optical properties of the platinum(II) porphyrin. Geometry optimization was conducted using DFT/B3LYP/LANL2DZ to obtain molecular structure, electronic structure and energy profile. Band gap energy (Eg), the density of states (DOS), and UV-visible spectra are the semiconductor parameters to study. Computational results show that platinum(II) porphyrin and substituted platinum(II) porphyrin have properties of semiconductor based on Eg value, DOS, and UV-visible spectra. The results show that Mulliken partial charges of electron withdrawing substituents are higher than the electron donating substituents (CH3, OH, and NH2). Eg values of the complexes with respect to the substituents follow this order: NH2 < OH < NO2 < COOH < I < CH3 < Br < F < H, for DOSHOMO values, the order is CH3 < NO2 < I < OH < F < NH2 < COOH < Br < H and the maximum wavelength (λmax) for UV-visible adsorption spectra follows this order: NH2 > OH > COOH > NO2 > I > Br > CH3 > F > H. Molecules with smaller Eg and DOSHOMO values and higher λmax are considered as the most appropriate semiconductor materials. Our results show that Pt(II)P-NH2 has the smallest Eg and the highest λmax among other substituted platinum(II) porphyrin molecules. Therefore, Pt(II)P-NH2 are the most suitable semiconductor material based on the aforementioned criteria.

Role of heteroatoms and substituents on the structure, reactivity, aromaticity, and absorption spectra of pyrene: a density functional theory study

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Bapan Saha ◽  
Pradip Kumar Bhattacharyya
Keyword(s):  
Density Functional Theory ◽  
Absorption Spectra ◽  
Density Functional ◽  
Structural Parameters ◽  
Visible Absorption ◽  
Functional Theory ◽  
Solvent Phase ◽  
Visible Spectra ◽  
Td Dft ◽  
Uv Visible

Abstract Effect of heteroatoms viz. BN and substituents viz. –Me (methyl), –OH (hydroxyl), –NH2 (amine), –COOH (carboxyl), and –CN (cyano) on the structural parameters, global reactivity, aromaticity, and UV-visible spectra of pyrene are studied with the help of density functional theory (DFT). Global reactivity parameters such as global hardness (η) and electrophilicity (ω) are calculated using density functional reactivity theory (DFRT). Time dependent density functional theory (TD-DFT) is explored for interpreting the UV-visible absorption spectra. Aromaticity of the pyrene rings are predicted from the nucleus independent chemical shift (NICS) values. Presence of BN unit and substituent induces reasonable impact on the studied parameters. The observed absorption spectra lie predominantly within the UV-region (both blue and red shifts are observed in presence of BN and substituent). HOMO energy and absorption spectra are affected nominally in solvent phase.

Time dependent-density functional theory (TD-DFT) and experimental studies of UV–Visible spectra and cyclic voltammetry for Cu(II) complex with Et2DTC

2018 ◽  
Vol 1157 ◽  
pp. 463-468 ◽  
Author(s):  
Eliana Maira A. Valle ◽  
Vinicius Gonçalves Maltarollo ◽  
Michell O. Almeida ◽  
Kathia Maria Honorio ◽  
Mauro Coelho dos Santos ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Cyclic Voltammetry ◽  
Density Functional ◽  
Experimental Studies ◽  
Time Dependent ◽  
Functional Theory ◽  
Visible Spectra ◽  
Td Dft ◽  
Uv Visible ◽  
Dependent Density

TD-DFT benchmark for UV-visible spectra of fused-ring electron acceptors using global and range-separated hybrids

2020 ◽  
Vol 22 (15) ◽  
pp. 7864-7874 ◽  
Author(s):  
Amjad Ali ◽  
Muhammad Imran Rafiq ◽  
Zhuohan Zhang ◽  
Jinru Cao ◽  
Renyong Geng ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Electron Acceptors ◽  
Time Dependent ◽  
Functional Theory ◽  
Visible Spectra ◽  
Td Dft ◽  
Fused Ring ◽  
Uv Visible ◽  
Dependent Density

The accuracy of Time-Dependent Density Functional Theory in predicting the vertical absorption wavelength of 50 widely-used fused-ring electron acceptors (FREAs) has been investigated by considering the solvent effects.

scholarly journals Prediction of Homolytic Bond Dissociation Enthalpies for Organic Molecules at near Chemical Accuracy with Sub-Second Computational Cost

2019 ◽  
Author(s):  
Peter St. John ◽  
Yanfei Guan ◽  
Yeonjoon Kim ◽  
Seonah Kim ◽  
Robert Paton
Keyword(s):  
Density Functional ◽  
Organic Molecules ◽  
Soot Formation ◽  
Chemical Reactivity ◽  
Hydrogen Abstraction ◽  
Computational Cost ◽  
Absolute Error ◽  
Functional Theory ◽  
Small Organic Molecules ◽  
Bond Dissociation

Bond dissociation enthalpies (BDEs) of organic molecules play a fundamental role in determining chemical reactivity. However, BDE computations at sufficiently high levels of quantum mechanical (QM) theory require substantial computing resources. We have therefore developed A machine-Learning derived, Fast, Accurate Bond dissociation Enthalpy Tool (ALFABET), capable of accurately predicting BDEs for organic molecules in a fraction of a second. Automated density functional theory (DFT) calculations at the M06-2X/def2-TZVP level of theory were performed for 42,577 small organic molecules, resulting in a dataset of 290,664 BDEs. A graph neural network was trained on a subset of these results, achieving a mean absolute error of 0.58 kcal/mol for the BDE values of unseen molecules. An interface for the developed prediction tool is available online at https://ml.nrel.gov/bde. The model rapidly and accurately predicts major sites of hydrogen abstraction in metabolism of drug-like molecules and determines the dominant molecular fragmentation pathways during soot formation.

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