Molecular structure and stability of dissolved lithium polysulfide species

2014 ◽  
Vol 16 (22) ◽  
pp. 10923-10932 ◽  
Author(s):  
M. Vijayakumar ◽  
Niranjan Govind ◽  
Eric Walter ◽  
Sarah D. Burton ◽  
Anil Shukla ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Chemical Stability ◽  
Theoretical Approach ◽  
Molecular Level ◽  
Dissolution Mechanism ◽  
Structure And Stability ◽  
Lithium Polysulfide ◽  
Subsequent Chemical

We present a molecular level study of the dissolution mechanism and subsequent chemical stability of lithium polysulfide species using a combined experimental and theoretical approach.

Molecular structure analysis of ascending aorta aneurysm upon atherosclerosis

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
I Mamarelis ◽  
V Mamareli ◽  
M Kyriakidou ◽  
O Tanis ◽  
C Mamareli ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Raman Spectra ◽  
Molecular Level ◽  
Ascending Aorta ◽  
Ir And Raman Spectra ◽  
Aggregate Formation ◽  
Aorta Aneurysm ◽  
Ft Ir ◽  
Molecular Structure Analysis ◽  
Ir And Raman

Abstract Background The atherosclerotic ascending aorta could represent a potential source of emboli or could be an indicator of atherosclerosis in general with high mortality. The mechanism of aneurysm formation and atherosclerosis of the ascending aorta at the molecular level has not yet been clarified. To approach the mechanism of ascending aortic lesions and mineralization at a molecular level, we used the non-destructive FT-IR, Raman spectroscopy, SEM and Hypermicroscope. Methods Six ascending aorta biopsies were obtained from patients who underwent aortic valve replacement (AVR) cardiac surgery. CytoViva (einst inc) hyperspectral microscope was used to obtain the images of ascending aorta. The samples were dissolved in hexane on a microscope glass plate. The FT-IR and Raman spectra were recorded with Nicolet 6700 thermoshintific and micro-Raman Reinshaw (785nm, 145 mwatt), respectively. The architecture of ascending aorta biopsies was obtained by using scanning electron microscope (SEM of Fei Co) without any coating. Results FT-IR and Raman spectra showed changes arising from the increasing of lipophilic environment and aggregate formation (Fig. 1). The band at 1744 cm–1 is attributed to aldehyde CHO mode due to oxidation of lipids. The shifts of the bands of the amide I and amide II bands to lower are associated with protein damage, in agreement with SEM data. The bands at about 1170–1000 cm–1 resulted from the C-O-C of advanced glycation products as result of connecting tissues fragmentations and polymerization. The spectroscopic data were analogous with the lesions observed with SEM and hypermicroscopic images. Conclusions The present innovate molecular structure analysis showed that upon ascending aorta aneurysm development an excess of lipophilic aggregate formation and protein lesions, changing the elasticity of the aorta's wall. The released Ca2+ interacted mostly with carbonate-terminal of cellular protein chains accelerated the ascending aorta calcifications. Figure 1. FT-IR and Raman spectra Funding Acknowledgement Type of funding source: None

A computational study on molecular structure and stability of tautomers of dipyrrole-based phenanthroline analogue

2018 ◽  
Vol 1145 ◽  
pp. 6-14
Author(s):  
Moyassar M. Meshhal ◽  
Mohamed F. Shibl ◽  
Safinaz H. El-Demerdash ◽  
Ahmed M. El-Nahas
Keyword(s):  
Molecular Structure ◽  
Computational Study ◽  
Structure And Stability

Effect of air-absorbed oxygen and moisture on the chemical stability of photoexcitedMg,ZnandEuphthalocyanines in dimethylformamide

2006 ◽  
Vol 10 (01) ◽  
pp. 43-54 ◽  
Author(s):  
Rudolf Słota ◽  
Gabriela Dyrda ◽  
Zbigniew Hnatejko ◽  
Jerzy Karolczak ◽  
Zdzisław Stryła
Keyword(s):  
Molecular Structure ◽  
Molecular Oxygen ◽  
Chemical Stability ◽  
Degradation Rate ◽  
Chemical Properties ◽  
Fluorescence Lifetimes ◽  
Metal Phthalocyanines ◽  
Molecular Stability ◽  
Stabilizing Effect ◽  
Specific Affinity

Absorption of oxygen and moisture from air by MPc-DMF systems was studied and related to the molecular stability demonstrated by phthalocyanine complexes (unsubstituted MPc's : MgPc , ZnPc and EuPc2; Pc = phthalocyanine ligand, C32H16N8) subjected to UV irradiation. A lower stability of air-exposed dimethylformamide solutions is observed and is due to a specific affinity for molecular oxygen revealed by the Pc macrocycle. SEM results proved oxygen molecules fixed to the phthalocyanine solids by forces strong enough to sustain desorption under vacuum. Absorption curves determined for MPc-DMF systems also indicate oxygen accommodated by the phthalocyanine moiety. This explains the predominantly oxygen-mediated photolysis, as well as the very short fluorescence lifetimes of metal phthalocyanines. The effect of air-absorbed moisture on the photostability is much less pronounced and practically insignificant for concentrations of H2O lower than 1%. An apparent stabilizing effect of water was observed and elucidated basing on kinetic considerations. The degradation rate of the photoexcited phthalocyanine moiety in air-exposed solutions depends on individual chemical properties and the molecular structure of the complex. EuPc2proved very stable whereas the photostability of ZnPc and MgPc gradually decreased in the course of time.

Synthesis, molecular structure and stability of fused bicyclic Δ4-1,2,4-oxadiazoline Pt(II) complexes

Polyhedron ◽  
2015 ◽  
Vol 98 ◽  
pp. 55-63 ◽  
Author(s):  
Jamal Lasri ◽  
Saied M. Soliman ◽  
M. Adília Januário Charmier ◽  
Mar Ríos-Gutiérrez ◽  
Luis R. Domingo
Keyword(s):  
Molecular Structure ◽  
Structure And Stability
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