Chemical reaction dynamics of PeCB and TCDD decomposition: A tight‐binding quantum chemical molecular dynamics study with first‐principles parameterization

The decomposition reaction dynamics of 2,3,4,4′,5‐penta‐chlorinated biphenyl (2,3,4,4′,5‐PeCB), 3,3′,4,4′,5‐penta‐chlorinated biphenyl (3,3′,4,4′,5‐PeCB), and 2,3,7,8‐tetra‐chlorinated dibenzo‐p‐dioxin (2,3,7,8‐TCDD) was clarified for the first time at atomic and electronic levels, using our novel tight‐binding quantum chemical molecular dynamics method with first‐principles parameterization. The calculation speed of our new method is over 5000 times faster than that of the conventional first‐principles molecular dynamics method. We confirmed that the structure, energy, and electronic states of the above molecules calculated by our new method are quantitatively consistent with those by first‐principles calculations. After the confirmation of our methodology, we investigated the decomposition reaction dynamics of the above molecules and the calculated dynamic behaviors indicate that the oxidation of the 2,3,4,4′,5‐PeCB, 3,3′,4,4′,5‐PeCB, and 2,3,7,8‐TCDD proceeds through an epoxide intermediate, which is in good agreement with the previous experimental reports and consistent with our static density functional theory calculations. These results proved that our new tight‐binding quantum chemical molecular dynamics method with first‐principles parameterization is an effective tool to clarify the chemical reaction dynamics at reaction temperatures. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005     

“化学在抗击新冠肺炎疫情中扮演的重要角色”专题教学

Considering COVID-19 epidemic prevention and control, education materials were excavated and refined, such as chemical disinfectants, typical drugs used in clinical treatment or trial and materials for preparation of medical protective equipment. We have carried out thematic teaching on "The important role of chemistry in the fight against COVID-19 epidemic", and integrated ideological and political education into the thematic teaching. Through thematic teaching, we can make students feel the charm of chemistry subject, stimulate students' interest in learning chemistry, fully mobilize students' learning enthusiasm and initiative, strengthen students' confidence and courage to overcome difficulties, cultivate the students' professional disciplines literacy and scientific literacy, activate students' love for the motherland, the people and the Communist Party of China.     

Synthesis of thermally crosslinkable fluorine‐containing poly(arylene ether ketone)s—II. Propargyl ether terminated poly(arylene ether ketone)s

Novel thermally crosslinkable fluorine‐containing poly(arylene ether ketone)s comprised of 2,3,5, 6‐tetrafluoro‐1,4‐phenylene moiety were synthesized by the termination of polymer chain ends with propargyl ether groups in order to improve solvent resistance. Crosslinking reaction occurred over 250°C through the formation of both chromen ring and polyene structure. This structure change brought about not only the outstanding solvent resistance but also the increase in glass transition temperature (T_g). The cured films also exhibited excellent thermal stability, transparency and hydrophobicity derived from fluorine atoms. Copyright © 2004 John Wiley & Sons, Ltd.     

Synthesis of benzimidazole derivatives as potential H1-antihistaminic agents

Several types of benzimidazole derivatives were prepared and were screened for H ₁-antihistaminic activity. Most of the compounds showed potent antihistaminic activity in vitro. Among them 2-[(1-piperazinyl)methyl]-benzimidazoles 14 and 2-[(1-homopiperazinyi)methyl]benzimidazoles 15 exhibited potent activity also in vivo.     

Immunosuppressive ent‐Kaurene Diterpenoids from Isodon serra

Three new enmein‐type ent‐kaurenoids, i.e., the two pairs 1 and 2 of 20‐epimers and the (20R)‐isomer 3 , besides the seven known diterpenoids 4 – 10 , were isolated from the aerial parts of Isodon serra. Their structures were elucidated by spectroscopic techniques and X‐ray diffraction. The immunosuppressive effect for T‐lymphocytes proliferation induced by Con A in BALB/c mouse was evaluated for the isolates 1 – 10 . They all displayed a remarkable inhibitory effect, with multi‐glycosides of Tripterygium wilfordii as positive reference substance (Table 3).     

Synthesis and pharmacology of 3,4-dihydro-3-oxo-1,4-benzoxazine-8-carboxamide derivatives, a new class of potent serotonin-3 (5-HT3) receptor antagonists.

A series of 3,4-dihydro-3-oxo-1,4-benzoxazine-8-carboxamide derivatives was synthesized and evaluated for serotonin-3 (5-HT3) receptor antagonistic activity assessed by their ability to antagonize the von Bezold-Jarish (BJ) effect in rats. Derivatives bearing 1-azabicyclo[2.2.2]oct-3-yl moiety as a basic function attached to the carboxamide at position 8 showed more potent antagonistic activity than those bearing the other three basic moieties. Structure-activity relationships of this series showed that methyl and chloro groups were more effective as substituents at positions 4 and 6, respectively. The representative compound 15 (Y-25130) in this series showed potent antagonistic activity on the BJ effect (ED50 = 1.3 micrograms/kg i.v.), high affinity for 5-HT3 receptor (Ki = 2.9 nM) and complete protection against cisplatin-induced emesis in dogs at a dose of 0.1 mg/kg i.v.     

Carbon dioxide fixation by microalgae photosynthesis using actual flue gas discharged from a boiler

To mitigate CO₂ discharged from thermal power plants, studies on CO₂ fixation by the photosynthesis of microalgae using actual exhaust gas have been carried out. The results are as follows.

新型四硫代富瓦烯衍生物的合成及其性质的研究

合成了3个新的含有卤素取代基的四硫代富瓦烯衍生物及6个新的相关化合物。利用溶液的电子吸收光谱对四硫代富瓦烯衍生物的性质进行了研究。研究结果表明, 四硫代富瓦烯衍生物的分子中π轨道之间的能级差较小, 因而分子具有较高的稳定性。     

微波等离子体炬发射光谱法去溶系统性能的研究

用微波等离子体矩（MPT）作激发光源，等离子体的工作气体为氩气，研究了气动雾化进样去溶系统的工作参数对分析性能的影响，探讨了水冷凝与浓硫酸吸收二者协同去溶的相关性，结果表明，OH （Q1带，带头谱线为308.520nm）的发射强度即可判别样品去溶效果。     

Langmuir monolayers of the long-chain alkyl derivatives of a nucleoside analogue and the formation of self-assembled nanoparticles

The long-chain alkyl derivatives of a nucleoside analogue-acyclovir were prepared in the paper. One is stearyl-glycero-succinyl-acyclovir (SGSA) with a single 18-carbon length (C18) alkyl chain. Another is dioctadecyl-aspartate-succinyl-acyclovir (DASA) with double C18 alkyl chains. They were prepared by the esterification of succinyl-acyclovir with the lipids, and sodium salts of them were also prepared. Guanine moieties and alkyl moieties bring the derivatives intermolecular hydrogen bonding and hydrophobic interaction in water separately. The forces are influenced by the number of alkyl chains and the charged state, and determine the solubility and the self-assembly behavior of the derivatives. The double alkyl-chain derivatives (DASA and DASA-Na) formed rigid Langmuir monolayers on air/water surface, while the single alkyl chain derivatives (SGSA and SGSA-Na) did not. However, cholesterol (Chol) could assist SGSA to form rigid monolayers through inserting into the alkyl chains of SGSA to mimic the second alkyl chain. SGSA self-aggregates in water were prepared by the injection method with tetrahydrofuran as solvent. Cuboid-like shape and nanoscale size demonstrated that SGSA self-aggregates were self-assembled nanoparticles. Shape, particle size, zeta potential and phase transition of the nanoparticles were characterized. And they showed an average size of 83.2 nm, a negative surface charge of -31.3-mV zeta potential and a gel-liquid crystalline phase transition of 50.38 degrees C. The formation mechanism of self-assembled nanoparticles was analyzed. Hydrophobic interaction of alkyl chains improves SGSA molecules to form bilayers, and then cuboid-like nanoparticles were obtained by layer-by-layer aggregation based on inter-bilayers hydrogen bonding. However, the charged guanine moieties make SGSA-Na lose the function of hydrogen bonding so that SGSA-Na only forms vesicles in water based on hydrophobic interaction. Strong hydrophobicity and wide-open rigid double alkyl chains of DASA and DASA-Na restrict self-assembly in water media, and no homogeneous suspensions were obtained. Therefore, the molecular self-assembly behavior of the long-chain alkyl derivatives of nucleoside analogues on water surface or in water media is determined by the number of alkyl chains and the charged state.