(Invited) Fullerenes Encapsulating an Ytterbium Atom: Molecular Structures and Chemical Properties

2013 ◽  
Keyword(s):  
Chemical Properties ◽  
Molecular Structures ◽  
Ytterbium Atom ◽  
And Chemical Properties

scholarly journals Design and Synthesis of Fluoro Analogues of Vitamin D

2021 ◽  
Vol 22 (15) ◽  
pp. 8191
Author(s):  
Fumihiro Kawagoe ◽  
Sayuri Mototani ◽  
Atsushi Kittaka
Keyword(s):  
Vitamin D ◽  
Vitamin D3 ◽  
Fluorine Atom ◽  
Chemical Properties ◽  
Molecular Structures ◽  
Physical And Chemical Properties ◽  
Design And Synthesis ◽  
Synthetic Methodologies ◽  
Physical And Chemical ◽  
And Chemical Properties

The discovery of a large variety of functions of vitamin D3 and its metabolites has led to the design and synthesis of a vast amount of vitamin D3 analogues in order to increase the potency and reduce toxicity. The introduction of highly electronegative fluorine atom(s) into vitamin D3 skeletons alters their physical and chemical properties. To date, many fluorinated vitamin D3 analogues have been designed and synthesized. This review summarizes the molecular structures of fluoro-containing vitamin D3 analogues and their synthetic methodologies.

scholarly journals Composition and light absorption of N-containing aromatic compounds in organic aerosols from laboratory biomass burning

2019 ◽  
Vol 19 (5) ◽  
pp. 2899-2915 ◽  
Author(s):  
Mingjie Xie ◽  
Xi Chen ◽  
Michael D. Hays ◽  
Amara L. Holder
Keyword(s):  
Experimental Data ◽  
Biomass Burning ◽  
Light Absorption ◽  
Aromatic Compounds ◽  
Chemical Properties ◽  
Molecular Structures ◽  
Forest Understory ◽  
Prescribed Fires ◽  
Volatile Organic ◽  
And Chemical Properties

Abstract. This study seeks to understand the compositional details of N-containing aromatic compounds (NACs) emitted during biomass burning (BB) and their contribution to light-absorbing organic carbon (OC), also termed brown carbon (BrC). Three laboratory BB experiments were conducted with two United States pine forest understory fuels typical of those consumed during prescribed fires. During the experiments, submicron aerosol particles were collected on filter media and subsequently extracted with methanol and examined for their optical and chemical properties. Significant correlations (p<0.05) were observed between BrC absorption and elemental carbon (EC)∕OC ratios for individual burns data. However, the pooled experimental data indicated that EC∕OC alone cannot explain the BB BrC absorption. Fourteen NAC formulas were identified in the BB samples, most of which were also observed in simulated secondary organic aerosol (SOA) from photooxidation of aromatic volatile organic compounds (VOCs) with NOx. However, the molecular structures associated with the identical NAC formula from BB and SOA are different. In this work, the identified NACs from BB are featured by methoxy and cyanate groups and are predominately generated during the flaming phase. The mass concentrations of identified NACs were quantified using authentic and surrogate standards, and their contributions to bulk light absorption of solvent-extractable OC were also calculated. The contributions of identified NACs to organic matter (OM) and BrC absorption were significantly higher in flaming-phase samples than those in smoldering-phase samples, and they correlated with the EC∕OC ratio (p<0.05) for both individual burns and pooled experimental data, indicating that the formation of NACs from BB largely depends on burn conditions. The average contributions of identified NACs to overall BrC absorption at 365 nm ranged from 0.087±0.024 % to 1.22±0.54 %, which is 3–10 times higher than their mass contributions to OM (0.023±0.0089 % to 0.18±0.067 %), so the NACs with light absorption identified in this work from BB are likely strong BrC chromophores. Further studies are warranted to identify more light-absorbing compounds to explain the unknown fraction (>98 %) of BB BrC absorption.

scholarly journals Comparative study of Danshen and Siwu decoction based on the molecular structures of the components and predicted targets

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yang Li ◽  
Li Qiao ◽  
Cong Chen ◽  
Zhenguo Wang ◽  
Xianjun Fu
Keyword(s):  
Comparative Study ◽  
Structural Feature ◽  
3D Structure ◽  
Chemical Properties ◽  
Principal Component ◽  
Molecular Structures ◽  
Physical And Chemical Properties ◽  
Material Basis ◽  
Physical And Chemical ◽  
And Chemical Properties

Abstract Background The sentence of “Danshen (Salvia Miltiorrhizae Radix et Rhizoma) and Siwu decoction are similar in function” was first recorded in an ancient Chinese medical book “Fu Ren Ming Li Lun”. This theory has far-reaching influence on the clinical practice of Chinese medicine and is highly respected by Chinese medical doctors. However, the theory has limitations and controversial part for there is no in-depth and system comparative study. Methods We collected the molecular structures of 129 compounds of Danshen and 81 compounds of Siwu decoction from the literatures. MACCS fingerprints and Tanimoto similarity were calculated based on the molecular structures for comparing the structural feature. Molecular descriptors which represent physical and chemical properties were calculated by Discovery Studio. Principal component analysis (PCA) of was performed based on the descriptors. The ADMET properties were predicted by FAF-Drugs4. The effect targets for the compounds with good ADMET properties were confirmed from experimental data and predicted using the algorithm comprising Bernoulli Naive Bayes profiling. Results Based on the molecular structures, the presented study compared the structural feature, physical and chemical properties, ADMET properties, and effect targets of compounds of Danshen and Siwu decoction. It is found that Danshen and Siwu decoction do not have the same main active components. Moreover, the 2D structure of compounds from Danshen and Siwu decoction is not similar. Some of the compounds of Danshen and Siwu decoction are similar in 3D structure. The compounds with good ADMET properties of Danshen and Siwu decoction have same predicted targets, but some have different targets. Conclusions It can be inferred from the result that Danshen and Siwu decoction have some similarities, but also present differences from each other in the structure of the compounds and predicted targets. This may be the material basis of the similar and different traditional efficacy of Danshen and Siwu decoction. The setence of “ Danshen and Siwu decoction are similar in function. “ which is used in clinical has its material basis and target connotation to some extent. However, the traditional effects of Danshen and Siwu decoction are not exactly the same.

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