scholarly journals Solid L-α-alanine: Spectroscopic properties and theoretical calculations

2012 ◽  
Vol 113 (11) ◽  
pp. 1266-1275 ◽  
Author(s):  
Yamilet Rodríguez-Lazcano ◽  
Belén Maté ◽  
Oscar Gálvez ◽  
Víctor J. Herrero ◽  
Isabel Tanarro ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Spectroscopic Properties

scholarly journals Detection of Chemical Weapon Agents Using Spectroscopic Probes: A Computational Study

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Letícia S. Braga ◽  
Érika F. Silva ◽  
Daiana T. Mancini ◽  
Eduardo P. da Rocha ◽  
Elaine F. F. da Cunha ◽  
...  
Keyword(s):  
Free Energy ◽  
Gibbs Free Energy ◽  
Organophosphorus Compounds ◽  
Computational Study ◽  
Theoretical Calculations ◽  
Spectroscopic Properties ◽  
Acetylcholinesterase Inhibition ◽  
Chemical Weapon ◽  
Fast Detection ◽  
Absorption Wavelength

Organophosphorus compounds are organic compounds widely employed in agriculture as well as in chemical weapons. The use in agriculture is due to their insecticidal properties. However, in chemical warfare, the use of organophosphorus is associated with acetylcholinesterase inhibition, which promotes the cholinergic syndromes. In this line, the fast detection of this class of compound is crucial for the determination of environmental exposure. This improved detection will naturally allow for more prompt courses of treatment depending on the contaminant findings. In this perspective, the dipyrrinone oxime (1) was employed for the detection of organophosphorus compounds that are employed as nerve agents, such as cyclosarin, sarin, soman, diethyl chlorophosphate, diisopropylfluorophosphate, 2-(dimethylamino)ethyl N,N-dimethylphosphoramidofluoridate, O-ethyl-S-[2-(diethylamino)ethyl]methylphosphonothioate, O-ethyl-S-[2(diisopropylamino)ethyl] methylphosphonothioate, and O,O-diethyl-S-[2-(diethylamino)ethyl] phosphorothioate, through fluorescent emission. The thermodynamics and kinetic parameters as well as spectroscopic properties of the complexes formed for 1 and all organophosphorus compounds previously cited were investigated by means of theoretical calculations. From our findings, only the diethyl chlorophosphate, 2-(dimethylamino)ethyl N,N-dimethylphosphoramidofluoridate, and O,O-diethyl-S-[2-(diethylamino)ethyl] phosphorothioate emitted fluorescence in the hexane, toluene, chloroform, dichloromethane, methanol, acetonitrile, water, and dimethyl sulfoxide solvents. The study of the absorption wavelength with the most polar solvent showed higher values compared to apolar solvents. In the same solvent, for instance, soman in hexane showed the lowest absorption wavelength value, 324.5 nm, and DCP the highest value, 330.8 nm. This behavior was observed in other tested solvents. The thermodynamic parameters indicate negative Gibbs free energy (ΔG) values for the O-ethyl-S-[2(diisopropylamino)ethyl] methylphosphonothioate with 1 reaction. On the other hand, the sarin and cyclosarin revealed the lowest Gibbs free energy (ΔG‡) values, being kinetically favorable and presenting more reactivity.

Styryl-based NLO chromophores: synthesis, spectroscopic properties, and theoretical calculations

2015 ◽  
Vol 56 (20) ◽  
pp. 2586-2589 ◽  
Author(s):  
Ergin Yalçın ◽  
Sylvain Achelle ◽  
Yasmina Bayrak ◽  
Nurgül Seferoğlu ◽  
Alberto Barsella ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Spectroscopic Properties ◽  
Nlo Chromophores

Ruthenium Complexes Containing Two Ru−(η2-Si−H) Bonds:  Synthesis, Spectroscopic Properties, Structural Data, Theoretical Calculations, and Reactivity Studies

1999 ◽  
Vol 121 (28) ◽  
pp. 6668-6682 ◽  
Author(s):  
Fabien Delpech ◽  
Sylviane Sabo-Etienne ◽  
Jean-Claude Daran ◽  
Bruno Chaudret ◽  
Khansaa Hussein ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Ruthenium Complexes ◽  
Structural Data ◽  
Spectroscopic Properties

scholarly journals Theoretical and Experimental Investigations of Large Stokes Shift Fluorophores Based on a Quinoline Scaffold

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2488
Author(s):  
Barbara Czaplińska ◽  
Katarzyna Malarz ◽  
Anna Mrozek-Wilczkiewicz ◽  
Aneta Slodek ◽  
Mateusz Korzec ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Stokes Shift ◽  
Visible Region ◽  
Spectroscopic Properties ◽  
Cellular Membrane ◽  
Structural Features ◽  
Quantum Yields ◽  
Experimental Investigations ◽  
Case Scenario ◽  
Fluorescence Quantum Yields

A series of novel styrylquinolines with the benzylidene imine moiety were synthesized and spectroscopically characterized for their applicability in cellular staining. The spectroscopic study revealed absorption in the ultraviolet–visible region (360–380 nm) and emission that covered the blue-green range of the light (above 500 nm). The fluorescence quantum yields were also determined, which amounted to 0.079 in the best-case scenario. The structural features that are behind these values are also discussed. An analysis of the spectroscopic properties and the theoretical calculations indicated the charge-transfer character of an emission, which was additionally evaluated using the Lippert–Mataga equation. Changes in geometry in the ground and excited states, which had a significant influence on the emission process, are also discussed. Additionally, the capability of the newly synthesized compounds for cellular staining was also investigated. These small molecules could effectively penetrate through the cellular membrane. Analyses of the images that were obtained with several of the tested styrylquinolines indicated their accumulation in organelles such as the mitochondria and the endoplasmic reticulum.

Theoretical Studies on the Structure and Spectroscopic Properties of 2,4-D (2,4-Diclorofenoxiacetic Acid)

2012 ◽  
Vol 2 (1) ◽  
pp. 1-11
Author(s):  
María G. Andino ◽  
Mariela I. Profeta ◽  
Jorge M. Romero ◽  
Nelly L. Jorge ◽  
Eduardo A. Castro
Keyword(s):  
Density Functional ◽  
Theoretical Calculations ◽  
Spectroscopic Properties ◽  
Uv Spectra ◽  
Basis Set ◽  
Basis Sets ◽  
Electronic Effects ◽  
B3lyp Method ◽  
Molecular Stability ◽  
2,4 Dichlorophenoxyacetic Acid

The 2,4-dichlorophenoxyacetic acid (2,4-D) is applied to and recovered from the leaf surfaces of garden bean and corn plants. This paper examines the theoretical study of the 2,4-D IR and UV spectra as well as the determination of its optimized molecular structure. Theoretical calculations are performed at the density functional theory (DFT) levels. The different structural and electronic effects determining the molecular stability of the conformers are discussed in a comparative fashion. The optimized geometry was calculated via the B3LYP method with 6-311G(d,p) and 6-311++G(d,p) basis sets and the FT-IR spectra was calculated by the density functional B3LYP method with the 6-311++G(d,p) basis set. The scaled theoretical wavenumbers show good agreement with the experimental values. A detailed interpretation of the infrared spectra of 2,4-D is reported.

scholarly journals Cyclopentadienyl coordination induces unexpected ionic Am−N bonding in an americium bipyridyl complex

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Brian N. Long ◽  
María J. Beltrán-Leiva ◽  
Cristian Celis-Barros ◽  
Joseph M. Sperling ◽  
Todd N. Poe ◽  
...  
Keyword(s):  
Spent Nuclear Fuel ◽  
Theoretical Calculations ◽  
Spectroscopic Properties ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
Coordination Environment ◽  
Trivalent Lanthanides ◽  
Key Factor ◽  
Bipyridyl Complex

AbstractVariations in bonding between trivalent lanthanides and actinides is critical for reprocessing spent nuclear fuel. The ability to tune bonding and the coordination environment in these trivalent systems is a key factor in identifying a solution for separating lanthanides and actinides. Coordination of 4,4′−bipyridine (4,4′−bpy) and trimethylsilylcyclopentadienide (Cp′) to americium introduces unexpectedly ionic Am−N bonding character and unique spectroscopic properties. Here we report the structural characterization of (Cp′3Am)2(μ − 4,4′−bpy) and its lanthanide analogue, (Cp′3Nd)2(μ − 4,4′−bpy), by single-crystal X-ray diffraction. Spectroscopic techniques in both solid and solution phase are performed in conjunction with theoretical calculations to probe the effects the unique coordination environment has on the electronic structure.

Spectroscopic investigations and theoretical calculations of DABCO induced xanthene bridged self-assembled zinc(II) porphyrin dimer

2016 ◽  
Vol 20 (05) ◽  
pp. 647-655 ◽  
Author(s):  
Li Xu ◽  
Tingting Huang ◽  
Xu Liang ◽  
John Mack ◽  
Jessica Harris ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Geometry Optimization ◽  
Spectroscopic Properties ◽  
Td Dft ◽  
Depth Study ◽  
Self Assembled ◽  
Porphyrin Dimer ◽  
Porphyrin Rings

An in-depth study of the electronic structure of a 1,4-diazabicyclo[2.2.2]octane (DABCO) induced molecular self-assembled xanthene-bridged and amide-bonded porphyrin dimer is reported. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations are used to identify trends in the optical spectroscopic properties. B3LYP geometry optimization predicts the formation of an almost perfectly eclipsed structure with respect to the two porphyrin rings with the analogous pyrrole nitrogens separated by 7.7–8.1 Å. The observed distinctive derivative-shaped band morphology of the pseudo-Faraday-A[Formula: see text] terms in the MCD spectra has been used to identify the main electronic Q and B-bands and to validate the TD-DFT calculations. The absence of a discernible splitting of the redox steps or a quenching of the fluorescence demonstrates that there is no significant exciton coupling between the two porphyrin rings.

ChemInform Abstract: Styryl-Based NLO Chromophores: Synthesis, Spectroscopic Properties, and Theoretical Calculations.

ChemInform ◽  
2015 ◽  
Vol 46 (36) ◽  
pp. no-no
Author(s):  
Ergin Yalcin ◽  
Sylvain Achelle ◽  
Yasmina Bayrak ◽  
Nurguel Seferoglu ◽  
Alberto Barsella ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Spectroscopic Properties ◽  
Nlo Chromophores
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