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 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.

Syntheses, theoretical studies, and crystal structures of [Ni(II)SSRRL](PF6)2 and [Ni(II)SRSRL](Cl)(PF6) that contains anagostic interactions

2020 ◽  
pp. 1-10
Author(s):  
Peyton C. Bainbridge ◽  
Rudy L. Luck ◽  
Nick K. Newberry
Keyword(s):  
Theoretical Calculations ◽  
Structural Data ◽  
Theoretical Studies ◽  
Redox Potentials ◽  
X Ray ◽  
H Nmr ◽  
Irreversible Oxidation ◽  
Square Planar ◽  
Reduced Products ◽  
Reversible Reduction

The syntheses of two square planar nickel complexes containing the condensation and subsequently reduced products obtained by reacting [Ni(en)3](BF4)2 and acetone are reported. The complexes 5,5,7,12,12,14-hexamethyl-1(S),4(S),8(R),11(R)-tetraazacyclotetradecane-nickel(II)[PF6]2 and 5,5,7,12,12,14-hexamethyl-1(S),4(R),8(S),11(R)-tetraazacyclotetradecane-nickel(II)[Cl][PF6] labelled as [Ni(II)SSRRL](PF6)2 and [Ni(II)SRSRL](Cl)(PF6), respectively, were found to have slightly different solubilities that allowed for their purification. The complexes were characterized by FTIR, 1H NMR, and UV–vis spectra. Redox potentials, determined by cyclic voltammetry, established that [Ni(II)SSRRL](PF6)2 exhibits a reversible oxidation (E1/2(ox) = 0.85 V) and reduction (E1/2(red) = −1.59 V), whereas [Ni(II)SRSRL](Cl)(PF6) displays an irreversible oxidation (Epa(ox) = 1.37 V) and reversible reduction (E1/2(red) = −1.62 V) relative to the ferrocene couple at 0.0 V. Single crystal X-ray determinations established that one of the compounds, [Ni(II)SSRRL](PF6)2, contained two [Formula: see text] anions, whereas the other compound, [Ni(II)SRSRL](Cl)(PF6), contained one Cl− and one [Formula: see text] anion. In the solid state, compound [Ni(II)SSRRL](PF6)2 was held together by H-bonds between H atoms on the Ni containing dication and F atoms in the [Formula: see text] anion. Compound [Ni(II)SRSRL](Cl)(PF6) crystallized in the form of dimers held together by interactions between H atoms attached to N atoms on adjacent cations binding to two Cl− anions in the middle with these dimers held together by further H-bonding to interstitial [Formula: see text] anions. Complex [Ni(II)SRSRL](Cl)(PF6) was found to contain anagostic interactions on the bases of NMR (downfield shift in C–H protons) and structural data (2.3 < d(H-Ni) < 2.9 Å), as well as theoretical calculations.

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

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

Cationic ordering in oxide glasses: the example of transition elements

2000 ◽  
Vol 64 (3) ◽  
pp. 409-424 ◽  
Author(s):  
L. Galoisy ◽  
L. Cormier ◽  
S. Rossano ◽  
A. Ramos ◽  
G. Calas ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Structural Data ◽  
Spectroscopic Properties ◽  
Oxide Glasses ◽  
Borosilicate Glasses ◽  
Transition Elements ◽  
Coordination Numbers ◽  
Cationic Distribution ◽  
X Ray Absorption ◽  
Chemically Selective

AbstractStructural data have been obtained on the cation surroundings in multi-component silicate and borosilicate glasses using chemically selective spectroscopic and scattering methods, such as extended X-ray absorption and neutron scattering with isotope substitution (NSIS). Transition elements such as Ni or Ti may occur in unusual 5-coordinated sites which coexist with other coordination numbers, depending on glass composition. Distribution of cationic sites in the glassy structure is responsible for unusual spectroscopic properties, as shown by Fe2+ Mössbauer spectroscopy. The environment of cations such as Zn, Zr or Mo, has been determined by EXAFS and discussed using the bond valence theory, which predicts the way to charge compensate the oxygen neighbours and which indicates the linkage of cationic sites with the silicate framework. Cation-cation correlations are given by NSIS up to ∼8 Á, indicating an extensive Medium Range Ordering (MRO) with corner- and edge-linked cationic polyhedra, for Ti and Ni-bearing glasses, respectively. This heterogeneous cationic distribution in glasses is consistent with the presence of two-dimensional domains in which cation mixing may occur, as shown in a Ca-Ni metasilicate glass. Three-dimensional domains have also been found by Ni-K edge EXAFS in the case of low alkali borate glasses, with a local structure which mimics some aspects of crystalline NiO. The presence of ordered cationic domains, clearly illustrated by Reverse Monte Carlo simulations helps to rationalize the physical properties of multi-component silicate glasses.

scholarly journals FEATURES OF THE STRUCTURAL PHASE STATE OF A FILM BASED ON A HIGH-ENTROPY AlNbTiZrCu ALLOY SYNTHESIZED BY DEPOSITION OF A MULTIELEMENT METAL PLASMA

2021 ◽  
pp. 693-707
Author(s):  
Юрий Федорович Иванов ◽  
Юрий Афанасьевич Абзаев ◽  
Анатолий Анатольевич Клопотов ◽  
Никита Андреевич Прокопенко ◽  
Олег Сергеевич Толкачев ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Structural Phase ◽  
Thermodynamic Characteristics ◽  
Structural Data ◽  
Lattice Parameter ◽  
Arc Plasma ◽  
Structural Phase State ◽  
High Entropy ◽  
Pulsed Electron Beam ◽  
Metal Plasma

В данной работе приведены результаты структурных исследований пленок толщиной до 5 мкм высокоэнтропийных сплавов системы AlNbTiZrCu . Пленки были синтезированы на металлических и металлокерамических подложках путем осаждения многоэлементной металлической плазмы, созданной электродуговым плазменно ассистированным одновременным независимым распылением нескольких катодов. Показано, что пленки являются слоистым материалом и имеют аморфнокристаллическую структуру. Установлено, что облучение пленок импульсным электронным пучком (18 кэВ, 20 Дж/см, 50 мкс, 3 имп., 0,3 с) сопровождается кристаллизацией материала. Показано, что в полученных пленках доминирует соединение состава AlNbTiZr с параметром решетки 0,32344 нм. На основе теоретических расчетов получены структурные данные кристаллической решетки AlTiZrNb и определены механические и термодинамические характеристики этого соединения. This paper presents the results of structural studies of films with a thickness of up to 5 microns of high-entropy alloys of the AlNbTiZrCu system. The films were synthesized on metal and cermet substrates by deposition of a multielement metal plasma created by electric arc plasma assisted simultaneous independent sputtering of several cathodes. It is shown that the films are a layered material and have an amorphous-crystalline structure. It was found that irradiation of films with a pulsed electron beam (18 keV, 20 J/cm, 50 gs, 3 imp., 0,3 s) is accompanied by crystallization of the material. It is shown that the resulting films are dominated by the compound of the AlNbTiZr composition with the lattice parameter of 0,32344 nm. On the basis of theoretical calculations, the structural data of the crystal AlTiZrNb lattice were obtained, mechanical and thermodynamic characteristics of this compound were determined.

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.

scholarly journals 4,5-Diazafluorene and 9,9’-Dimethyl-4,5-Diazafluorene as Ligands Supporting Redox-Active Mn and Ru Complexes

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3189
Author(s):  
Wade C. Henke ◽  
Julie A. Hopkins ◽  
Micah L. Anderson ◽  
Jonah P. Stiel ◽  
Victor W. Day ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Visible Region ◽  
Structural Data ◽  
Spectroscopic Properties ◽  
X Ray Diffraction ◽  
Absorption Data ◽  
Redox Active ◽  
Ligand Charge Transfer ◽  
Ru Complexes ◽  
Active Nature

4,5-diazafluorene (daf) and 9,9’-dimethyl-4,5-diazafluorene (Me2daf) are structurally similar to the important ligand 2,2’-bipyridine (bpy), but significantly less is known about the redox and spectroscopic properties of metal complexes containing Me2daf as a ligand than those containing bpy. New complexes Mn(CO)3Br(daf) (2), Mn(CO)3Br(Me2daf) (3), and [Ru(Me2daf)3](PF6)2 (5) have been prepared and fully characterized to understand the influence of the Me2daf framework on their chemical and electrochemical properties. Structural data for 2, 3, and 5 from single-crystal X-ray diffraction analysis reveal a distinctive widening of the daf and Me2daf chelate angles in comparison to the analogous Mn(CO)3(bpy)Br (1) and [Ru(bpy)3]2+ (4) complexes. Electronic absorption data for these complexes confirm the electronic similarity of daf, Me2daf, and bpy, as spectra are dominated in each case by metal-to-ligand charge transfer bands in the visible region. However, the electrochemical properties of 2, 3, and 5 reveal that the redox-active Me2daf framework in 3 and 5 undergoes reduction at a slightly more negative potential than that of bpy in 1 and 4. Taken together, the results indicate that Me2daf could be useful for preparation of a variety of new redox-active compounds, as it retains the useful redox-active nature of bpy but lacks the acidic, benzylic C–H bonds that can induce secondary reactivity in complexes bearing daf.

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