scholarly journals Etude chimique et spectroscopique du système B(SCH3)3–B(NCS)3

1979 ◽  
Vol 57 (10) ◽  
pp. 1122-1126 ◽  
Author(s):  
Habib-Raman Atchekzai ◽  
Henri Mongeot ◽  
Jacques Dazord ◽  
Jean-Pierre Tuchagues
Keyword(s):  
Mass Spectrometry ◽  
Room Temperature ◽  
Low Concentration ◽  
Nmr Data ◽  
Donor Acceptor ◽  
Set Up

Reaction of trimethylthioborate, B(SMe)3, with triisothiocyanatoborane, B(NCS)3, at room temperature gives mixtures containing B(SMe)3, the mixed compounds B(NCS)(SMe)2 and B(NCS)2(SMe) in low concentration, and association compounds. The previous compounds cannot be isolated due to equilibria being set up. Mass spectrometry, infrared and nmr data are reported. Structures involving S–B donor–acceptor bonds between the monomers are proposed for the association compounds {B(NCS)2(SMe)}2, {B(NCS)2(SMe)}2{B(NCS)3}, and {B(NCS)2(SMe)}2{B(NCS)3}2. Reaction of these compounds with trimethylamine yields Me3NB(NCS)3 and Me3NB(NCS)2(SMe). The same reaction with dimethylsulphide is incomplete and yields only Me2SB(NCS)3. Acidity strength decreases in the order B(NCS)3 > B(NCS)2(SMe) > B(NCS)(SMe)2 > B(SMe)3. This trend explains why dimerization of B(NCS)2(SMe) occurs whereas B(NCS)(SMe)2 is unassociated.

scholarly journals Thermochromic aggregation-induced dual phosphorescence via temperature-dependent sp3-linked donor-acceptor electronic coupling

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tao Wang ◽  
Zhubin Hu ◽  
Xiancheng Nie ◽  
Linkun Huang ◽  
Miao Hui ◽  
...  
Keyword(s):  
Excited State ◽  
Room Temperature ◽  
Electronic Coupling ◽  
Temperature Dependent ◽  
Molecular Systems ◽  
Donor And Acceptor ◽  
Theoretical Investigations ◽  
Donor Acceptor ◽  
And Control ◽  
Two Temperature

AbstractAggregation-induced emission (AIE) has proven to be a viable strategy to achieve highly efficient room temperature phosphorescence (RTP) in bulk by restricting molecular motions. Here, we show that by utilizing triphenylamine (TPA) as an electronic donor that connects to an acceptor via an sp3 linker, six TPA-based AIE-active RTP luminophores were obtained. Distinct dual phosphorescence bands emitting from largely localized donor and acceptor triplet emitting states could be recorded at lowered temperatures; at room temperature, only a merged RTP band is present. Theoretical investigations reveal that the two temperature-dependent phosphorescence bands both originate from local/global minima from the lowest triplet excited state (T1). The reported molecular construct serves as an intermediary case between a fully conjugated donor-acceptor system and a donor/acceptor binary mix, which may provide important clues on the design and control of high-freedom molecular systems with complex excited-state dynamics.

Fe-Ti Bimetal Oxide Adsorbent for Removing Low Concentration H2S at Room Temperature

2021 ◽  
pp. 1-21
Author(s):  
Zhuangzhuang Guo ◽  
Zhihong Zhang ◽  
Xiaoyan Cao ◽  
Dongfang Feng
Keyword(s):  
Room Temperature ◽  
Low Concentration

scholarly journals Two New Phomaligols from the Marine-Derived Fungus Aspergillus flocculosus and Their Anti-Neuroinflammatory Activity in BV-2 Microglial Cells

Marine Drugs ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. 65
Author(s):  
Byeoung-Kyu Choi ◽  
Duk-Yeon Cho ◽  
Dong-Kug Choi ◽  
Phan Thi Hoai Trinh ◽  
Hee Jae Shin
Keyword(s):  
Nitric Oxide ◽  
Mass Spectrometry ◽  
Optical Rotation ◽  
Chemical Oxidation ◽  
Culture Broth ◽  
Membered Ring ◽  
Microglial Cells ◽  
No Production ◽  
Nmr Data ◽  
Ic50 Value

Two new phomaligols, deketo-phomaligol A (1) and phomaligol E (2), together with six known compounds (3–8) were isolated from the culture broth of the marine-derived fungus Aspergillus flocculosus. Compound 1 was first isolated as a phomaligol derivative possessing a five-membered ring. The structures and absolute configurations of the new phomaligols were determined by detailed analyses of mass spectrometry (MS), nuclear magnetic resonance (NMR) data, optical rotation values and electronic circular dichroism (ECD). In addition, the absolute configurations of the known compounds 3 and 4 were confirmed by chemical oxidation and comparison of optical rotation values. Isolated compounds at a concentration of 100 μM were screened for inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS)-induced BV-2 microglial cells. Among the compounds, 4 showed moderate anti-neuroinflammatory effects with an IC50 value of 56.6 μM by suppressing the production of pro-inflammatory mediators in activated microglial cells without cytotoxicity.

scholarly journals Exploring the Structural Chemistry of Pyrophosphoramides: N,N′,N″,N‴-Tetraisopropylpyrophosphoramide

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 149-163
Author(s):  
Duncan Micallef ◽  
Liana Vella-Zarb ◽  
Ulrich Baisch
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray Diffraction ◽  
X Ray

N,N′,N″,N‴-Tetraisopropylpyrophosphoramide 1 is a pyrophosphoramide with documented butyrylcholinesterase inhibition, a property shared with the more widely studied octamethylphosphoramide (Schradan). Unlike Schradan, 1 is a solid at room temperature making it one of a few known pyrophosphoramide solids. The crystal structure of 1 was determined by single-crystal X-ray diffraction and compared with that of other previously described solid pyrophosphoramides. The pyrophosphoramide discussed in this study was synthesised by reacting iso-propyl amine with pyrophosphoryl tetrachloride under anhydrous conditions. A unique supramolecular motif was observed when compared with previously published pyrophosphoramide structures having two different intermolecular hydrogen bonding synthons. Furthermore, the potential of a wider variety of supramolecular structures in which similar pyrophosphoramides can crystallise was recognised. Proton (1H) and Phosphorus 31 (31P) Nuclear Magnetic Resonance (NMR) spectroscopy, infrared (IR) spectroscopy, mass spectrometry (MS) were carried out to complete the analysis of the compound.

Hydrogen Transport in 34CrMo4 Martensitic Steel: Influence of Microstructural Defects on H Diffusion

2012 ◽  
Vol 323-325 ◽  
pp. 485-490 ◽  
Author(s):  
L. Moli-Sanchez ◽  
F. Martin ◽  
E. Leunis ◽  
J. Chêne ◽  
M. Wery
Keyword(s):  
Diffusion Coefficient ◽  
Room Temperature ◽  
Martensitic Steel ◽  
Hydrogen Trapping ◽  
Martensitic Steels ◽  
Hydrogen Diffusivity ◽  
Apparent Diffusion ◽  
Quenched Steel ◽  
Set Up ◽  
Permeation Test

The electrochemical permeation technique was used to evaluate the effect of the microstructure on hydrogen diffusivity and hydrogen trapping at room temperature in martensitic steels. A detailed study of the electrochemical permeation technique was first performed in order to identify the boundary conditions of a permeation test in the selected experimental set-up. The validity of the apparent diffusion coefficient derived from this test is also discussed. A 34CrMo4 quenched steel has been selected and designed at three tempering temperatures (200°C, 540°C and 680°C) in order to obtain three different microstructures. According to permeation measurements, H diffusion strongly depends on the microstructure. The material tempered at 540°C exhibits the smallest diffusion coefficient and the largest fraction of reversible traps at room temperature.

scholarly journals Investigation of Biotransformation Products of p-Methoxymethylamphetamine and Dihydromephedrone in Wastewater by High-Resolution Mass Spectrometry

Metabolites ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 66
Author(s):  
Juliet Kinyua ◽  
Aikaterini K. Psoma ◽  
Nikolaos I. Rousis ◽  
Maria-Christina Nika ◽  
Adrian Covaci ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Wastewater Treatment Plants ◽  
High Resolution Mass Spectrometry ◽  
Transformation Products ◽  
New Psychoactive Substances ◽  
Batch Reactors ◽  
Flight Mass Spectrometry ◽  
Detection And Identification ◽  
Wastewater Samples ◽  
Set Up

There is a paucity of information on biotransformation and stability of new psychoactive substances (NPS) in wastewater. Moreover, the fate of NPS and their transformation products (TPs) in wastewater treatment plants is not well understood. In this study, batch reactors seeded with activated sludge were set up to evaluate biotic, abiotic, and sorption losses of p-methoxymethylamphetamine (PMMA) and dihydromephedrone (DHM) and identify TPs formed during these processes. Detection and identification of all compounds was performed with target and suspect screening approaches using liquid chromatography quadrupole-time-of-flight mass spectrometry. Influent and effluent 24 h composite wastewater samples were collected from Athens from 2014 to 2020. High elimination rates were found for PMMA (80%) and DHM (97%) after a seven-day experiment and degradation appeared to be related to biological activity in the active bioreactor. Ten TPs were identified and the main reactions were O- and N-demethylation, oxidation, and hydroxylation. Some TPs were reported for the first time and some were confirmed by reference standards. Identification of some TPs was enhanced by the use of an in-house retention time prediction model. Mephedrone and some of its previously reported human metabolites were formed from DHM incubation. Retrospective analysis showed that PMMA was the most frequently detected compound.

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