electronic absorption
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Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7631
Author(s):  
Temitope T. Abiola ◽  
Nazia Auckloo ◽  
Jack M. Woolley ◽  
Christophe Corre ◽  
Stéphane Poigny ◽  
...  

Plants, as with humans, require photoprotection against the potentially damaging effects of overexposure to ultraviolet (UV) radiation. Previously, sinapoyl malate (SM) was identified as the photoprotective agent in thale cress. Here, we seek to identify the photoprotective agent in a similar plant, garden cress, which is currently used in the skincare product Detoxophane nc. To achieve this, we explore the photodynamics of both the garden cress sprout extract and Detoxophane nc with femtosecond transient electronic absorption spectroscopy. With the assistance of liquid chromatography-mass spectrometry, we determine that the main UV-absorbing compound in garden cress sprout extract is SM. Importantly, our studies reveal that the photoprotection properties of the SM in the garden cress sprout extract present in Detoxophane nc are not compromised by the formulation environment. The result suggests that Detoxophane nc containing the garden cress sprout extract may offer additional photoprotection to the end user in the form of a UV filter booster.


2021 ◽  
Author(s):  
Wade Henke ◽  
Jonah Stiel ◽  
Victor Day ◽  
James Blakemore

Ligands based upon the 4,5-diazafluorene core are an important class of emerging ligands in organometallic chemistry, but the structure and electronic properties of these ligands have received less attention than they deserve. Here, we show that 9,9′-dimethyl-4,5-diazafluorene (Me2daf) can stabilize low-valent complexes through charge delocalization into its conjugated π-system. Using a new platform of [Cp*Rh] complexes with three accessible formal oxidation states (+III, +II, and +I), we show that the methylation in Me2daf is protective, blocking Brønsted acid-base chemistry commonly encountered with other daf-based ligands. Electronic absorption spectroscopy and single-crystal X-ray diffraction analysis of a family of eleven new compounds, including the unusual Cp*Rh(Me2daf), reveal features consistent with charge delocalization driven by π-backbonding into the LUMO of Me2daf, reminiscent of behavior displayed by the workhorse 2,2′-bipyridyl ligand. Taken together with spectrochemical data demonstrating clean conversion between oxidation states, our findings show that 9,9′-dialkylated daf-type ligands are promising building blocks for applications in reductive chemistry and catalysis.


2021 ◽  
Vol 2063 (1) ◽  
pp. 012030
Author(s):  
Enas Hazim Mohammed ◽  
Sahbaa Ali Ahmed ◽  
Sariya Waleed Zedan

Abstract New complexes of dithiocarbamate of the general formula [M(2,4-dinitrphenhydra - dtc)2], [MM’(2,4-dinithrphenhydra-dtc)4] where: M=Fe (II), Co(II), Ni(II), M’=Zn(II), 2,4- dinitrphenhydra-dtc=2,4- di nitro phenyl hydrazine dithiocarbamate and [M(l,10-phen)3][M’(2,4 – dinitrphenhydra-dtc)4], [M(1,10- phen)3][M’2(2,4-dinitrphenhydra - dtc)6] Where: M=Co(II), Ni(II), M’=Zn(II), (1,10-phen)= 1,10-phenanthroline monohydrate. Have been prepared and characterized by atomic absorption spectroscopy infrared, conductance measurements, electronic absorption spectra, nuclear magnetic resonance and magnetic susceptibility measurements. Magnetic moments and electronic spectra indicate that the complexes of the type [M(2,-dinitrphenhydra-dtc)2], [MM’(2,4-dinitrphenhydra - dtc)4] are of square planner geometry while the complexes of the type [M(1,10-phen)3][M’(2,4-dinitrphenhydra-dtc)4] and [M(1,10 phen)3][M’2(2,4-dinitrphenhydra-dtc)6] have octahedral geometry.


Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1656
Author(s):  
Dana Ortansa Dorohoi ◽  
Dan Gheorghe Dimitriu ◽  
Ana Cezarina Morosanu ◽  
Nicoleta Puica Melniciuc ◽  
Ion Hurjui ◽  
...  

Four carbanion monosubstituted p-aryl-1,2,4-triazol-1-ium methylids are subjected to a comparative study between their spectral and quantum-mechanical parameters in order to obtain more information about their structural features in hydroxyl solvents as water and ethanol and also on the nature of electronic absorption transitions from the visible range. The quantum mechanical analysis, made by the Spartan’14 program, established a series of molecular parameters of the studied ylids important for their reactivity and for intermolecular interactions with hydroxyl liquids. An extensive solvatochromic study of 1,2,4-triazol-1-ium ylids is impossible due to their limited solubility in liquids. Binary solvent mixtures of water and ethanol with known solvent parameters from the literature were used for this study. The electronic absorption spectra in binary solvents water and ethanol were used to establish the influence of intermolecular interactions on the spectral characteristics of the studied methylids and also on the composition of their first solvation shell in ternary solutions. The difference between the interaction energies in molecular pairs ylid–water and ylid–ethanol was determined based on the statistical cell model applied to the ternary solutions of the type of ylid + water + ethanol. The obtained values are very small due to the hydroxylic nature of the two solvents.


Author(s):  
Babita Bisht ◽  
Venkataramana Imandi ◽  
Sanjay Pant ◽  
Anik Sen

In this paper, we have discussed for the first time a detailed electronic absorption study of the mono-azo dye Direct Yellow 27 [C[Formula: see text]H[Formula: see text]N4Na2O9S3] (DY-27) with five different homogeneous media by applying experimental and theoretical techniques along with some new characteristics of DY-27 in the field of solar cells as well as antiviral activities. A clear absorption band in the UV-visible region was observed, although the absorption maxima lie in the visible region. The electronic absorption transitions observed in our study were fully spin and symmetry allowed transitions with [Formula: see text]–[Formula: see text] character. Time-dependent density functional theory (TD-DFT) analysis has been done for understanding the electronic and the charge transfer performance. Moreover, the impacts of polar protic and polar aprotic solvents in the structural variation of DY-27 have been reported here. Further, applications of the dye in the field of solar cell, as well as antiviral activity, were performed using molecular modeling approaches. The dye exhibited a D–[Formula: see text]–A–A structure with a high light-harvesting efficiency (LHE) and good injection efficiency acts as an effective dye sensitized solar cell (DSSC). Molecular docking studies of the dye DY-27 performed with M-protease of the different corona viruses, MERS, SARS-CoV-1 and SARS-CoV-2 indicated comparable binding energies with the controlled inhibitors and best interactions are observed for the SARS-CoV-1.


Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 757
Author(s):  
Tamara Jovanović

The stable isomers of the higher fullerenes C76-D2 and C84-D2:22, as well as fullerenes C60 and C70 were isolated from carbon soot by the new and improved extraction and chromatographic methods and processes. Characterizations of the C84-D2:22 isomer in this study were performed by infrared and electronic absorption spectroscopy. All of the experimentally observed IR and UV/VIS bands were in excellent agreement with the semi-empirical, DFT and TB potential theoretical calculations for this molecule. The molar extinction coefficients and the integrated molar extinction coefficients of the observed larger number of completely separated infrared absorption maxima and shoulders of fullerene C84-D2:22, as well as of its main convoluted maxima, in different and new relevant entire integration ranges, including neighboring, and all surrounding absorption shoulders were determined and their relative intensities compared. In addition, the molar absorptivity of the electronic absorption bands of this carbon cluster was found. The new IR and UV/VIS spectroscopic parameters that are significant for the quantitative determination, identification and numerous possible applications of C84-D2:22 are obtained and their changes compared to C76-D2 observed. Isolated and characterized C84-D2:22, as well as other fullerenes from this research can be used in electronic, optical, chemical and biomedical devices, superconductors, semiconductors, batteries, catalysts, polymers, sensors, solar cells, nanophotonic lenses with better optical transmission, refraction and wettability, diagnostic and therapeutic pharmaceutical substances, such as those against diabetes, cancer, neurodegenerative disorders, free radical scavenging, radio nuclear, antibacterial and antiviral agents that can inhibit HIV 1, HSV, COVID-19, influenza, malaria and so forth.


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