赣南清溪离子吸附型稀土矿元素迁移富集特征研究

离子吸附型稀土矿床是中国特有的稀土资源。对这一类型矿床及周边的地质环境,风化壳中稀土进行研究具有较高的产学研价值。本文通过对中国赣南典型稀土矿区花岗岩风化壳进行元素地球化学分析,并结合相关地球化学参数与图解,结果表明：研究区成矿花岗岩风化壳形成于强化学风化条件,发育成熟度高,处于晚期去Si阶段;稀土元素地球化学参数显示,风化壳整体的稀土配分特征主要继承于成矿母岩;稀土元素主要以离子交换态在风化剖面中迁移,并受pH值、微生物活动、氧化还原条件等多种因素控制。     

镧系元素的电子转移反应（Ⅳ）铽原碲酸根配合物在KOH水溶液中还原反应的动力学和机理

从水溶液中制备了试（Ⅳ）原碲酸根配合物，利用紫外－可见光谱研究了其Ｌ→Ｍ电荷迁移跃迁，探讨了配合物阴离子在ＫＯＨ水溶液中自发还原反应的动力学规律，测出了电子转移过程的动力学参数。根据实验现象及测定结果推出了Ｔｂ４＋原碲酸根配合离子在水溶液中自发还原的机理，并作了验证。     

Synthesis,Mechanism Elucidation and Biological Insights of Tellurium(IV)-Containing Heterocycles

Inspired by the synthetic and biological potential of organotellurium substances, a series of five- and six-membered ring organotelluranes containing a Te−O bond were synthesized and characterized. Theoretical calculations elucidated the mechanism for the oxidation-cyclization processes involved in the formation of the heterocycles, consistent with chlorine transfer to hydroxy telluride, followed by a cyclization step with simultaneous formation of the new Te−O bond and deprotonation of the OH group. Moreover, theoretical calculations also indicated anti-diastereoisomers to be major products for two chirality center–containing compounds. Antileishmanial assays against Leishmania amazonensis promastigotes disclosed 1,2λ⁴-oxatellurane LQ50 (IC₅₀=4.1±1.0; SI=12), 1,2λ⁴-oxatellurolane LQ04 (IC₅₀=7.0±1.3; SI=7) and 1,2λ⁴-benzoxatellurole LQ56 (IC₅₀=5.7±0.3; SI=6) as more powerful and more selective compounds than the reference, being up to four times more active. A stability study supported by ¹²⁵Te NMR analyses showed that these heterocycles do not suffer structural modifications in aqueous-organic media or at temperatures up to 65 °C.     

固态电解质中锂离子传输机理研究进展

Inorganic crystalline solid electrolytes exhibit excep tional room-temperature ionic conductivities, giving them the potential to enable all-solid-state lithium (Li) - ion batteries. Developing new high-performance electrolytes is one of the most critical challenges to realize solid-state batteries, which requires understanding how chemistry facilitates fast ionic conduction and what the Li-ion migration mechanism is in in organic solid electrolytes. In this review, we aim to summarize recent fundamental research progress in Li-ion transport, including crystal structure, behavior of ion migration (i.e., single-ion jump and multi-ions cooperative migration), and the relationship between ion migration and microstructure. Generally, ion transport in crystalline structure can be categorized into vacancy and non-vacancy mechanism. For Li-ion conduction, the migration can be achieved through single-ion hopping and collective diffusion mechanism. For single-ion hopping mechanism, the diffusivity is determined by the depth of potential well (activation energy) and lattice dynamics;whereas in the later mechanism Li-ion moving from high potential to low potential could partially offset the energy required for Li-ion moving from low potential to high potential. By studying the collective diffusion from the perspective of local structures, it is believed that collective diffusion in fast ion conductor originates from the local 野dual Li-S/O冶 structure units, which can be characterized by the 野nearest Li-Li distance冶. Next, the paradigm of ion transport in solids is summarized. It is pointed out that most ion conductors follow Meyer-Neldel rule, where the activation energy and pre-exponential factor are mutual compensating. As a result, a balance should be adapted between these two values to achieve high Li-ion conductivity. However, for some fast ion conductors, the relationship does not follow the Meyer-Neldel rule (i.e., anti-Meyer-Neldel rule). Therefore, the physical significance of anti-Meyer-Neldel rule should be understood to develop next-generation lithium ion conductors. In the end, future perspectives and open questions are proposed to design and develop high-performance inorganic solid electrolytes. © 2021 Chinese Chemical Society. All rights reserved.     

Developments on the Chemistry of Tellurium and Selenium Azides

Abstract

We have been carrying out systematic studies on the preparation and properties of tellurium halide and pseudohalide compounds with a focus on tellurium azides. We were successful in the synthesis of various tellurium azides of both covalent and ionic nature. Several tellurium(IV) azides, tellurium(II) azides, and the first tellurium(VI) azides can be prepared in reasonable amounts. The first structural information of selenium azides is obtained for covalent and ionic derivatives, and spectroscopic data for the existence of selenium(iv) polyazides.     

Kinetics and Mechanism of the Nucleophilic Substitution of Tellurium(II) Dialkanethiolates,Te(SR1)2 with Thiols,HSR2

The equilibrium reaction between tellurium(II) dithiolates and thiols, Te(SR¹)₂ + 2 HSR² ? Te(SR²)₂ + 2 HSR¹ was studied by means of ¹H- and ¹²⁵Te NMR spectroscopy and ab initio quantum chemical methods. It was found that the reaction is catalyzed by Brønsted acids and bases, the catalytic activity corresponding to the strength of the respective acid or base. Investigation of the initial step of the reaction, Te(SR¹)₂ + HSR² ? Te(SR¹)(SR²) + HSR¹, showed it to proceed according to first order kinetics for Te(SR¹)₂, HSR² and for the catalyst. Ab initio geometry optimizations and frequency calculations suggest [Te(SR¹)(HSR¹)(HSR²)]⁺ and [Te(SR¹)₂(SR²)]^? to be stable intermediates and not transition states in the acid and base catalyzed reactions, respectively. The reaction hence proceeds via an additional elimination rather than an S _N 2 mechanism. The catalytic activity displayed by acids and bases can be applied to reduce the temperature in synthesis of thermally labile tellurium(II) dithiolates.     

二茂铁自组装分子结中电荷隧穿与跳跃传输的机理研究

采用硫醇自组装单层膜结合悬浮纳米线技术制备了分子结器件, 对比研究了非电活性的1-十一烷基硫醇(C11)和电活性的二茂铁己硫醇(FHT)分子结的电荷传输特性. 结合两种传输机理, 提出一种新的模型拟合了分子结的电流-电压特性, 发现了氧化还原活性中心二茂铁(Ferrocene, Fc)可以使电荷传输机理由隧穿变成隧穿与跳跃共存. 结合变温实验验证了这一机理, 并对这种混合机理出现的原因进行了分析.     

Elucidation of the Transport Mechanism of Puerarin and Gastrodin and Their Interaction on the Absorption in a Caco-2 Cell Monolayer Model

Puerarin (PUR) and gastrodin (GAS) are often used in combined way for treating diseases caused by microcirculation disorders. The current study aimed to investigate the absorption and transportation mechanism of PUR and GAS and their interaction via Caco-2 monolayer cell model. In this work, the concentration in Caco-2 cell of PUR and GAS was determined by HPLC method. The bidirectional transport of PUR and GAS and the inhibition of drug efflux including verapamil and cyclosporine on the transport of these two components were studied. The mutual influence between PUR and GAS, especially the effect of the latter on the former of the bidirectional transport were also investigated. The transport of 50 μg·mL⁻¹ PUR in Caco-2 cells has no obvious directionality. While the transport of 100 and 200 μg·mL⁻¹ PUR presents a strong directionality, and this directionality can be inhibited by verapamil and cyclosporine. When PUR and GAS were used in combination, GAS could increase the absorption of PUR while PUR had no obvious influence on GAS. Therefore, the compatibility of PUR and GAS is reasonable, and GAS can promote the transmembrane transport of PUR, the effect of which is similar to that of verapamil.     

Heavy Metal Contamination and Accumulation in Soil and Plant Species from the Xinqiao Copper Deposit,Anhui Province,China

The distribution and accumulation of heavy metals in soil and various plants were investigated in Xinqiao, the location of one of the largest copper deposits in China. The concentrations of cadmium, copper, lead, and zinc were determined by inductively coupled plasma–mass spectrometry (ICP–MS), and the results suggest that the soil was contaminated by mining activities. Plants grown around the study area accumulated these metals at various concentrations. The concentrations of metals in the plants indicated that the accumulation levels were not consistent with the relative concentrations in the corresponding soils. Almost all plants primarily accumulated heavy metals in above-ground tissues, especially Commelina communis. High biological transfer coefficients for Buddleja davidii, Rumex acetosa, Debregeasia edulis, Commelina communis, and Rosacfolius smith for some metals indicate accumulation in stems and leaves and identify these plants as hyperaccumulators.     

Control on Crystal Forms of Ultrafine Barium Carbonate Particles and Study on its Mechanism

1 INTRODUCTION Barium carbonate is one of the important che- mical materials as well as one of the most important barium salts. Its application covers multitudinous in- dustries and fields such as building material, meta- llurgy, electron, chemical industry and so on[1]. With the fast development of science and technology, it is becoming more and more demanding with barium carbonate’s quality, and more and more scientific workers do researches on the control of Barium car- bonate’s crys…     

贵州省普安矿区17号煤层中Au的富集成因研究

运用中子活化分析（INAA）、带能谱的扫描电镜（SEM-EDX）和电子探针（EMPA）研究了贵州省普安矿区17号煤层刻槽样中Au元素的含量、分布特征、赋存状态及富集机理。结果表明,17号煤层中Au的质量分数为2.61×10^-9～9.73×10^-9,平均6.29×10^-9,大于世界煤和中国煤中Au的平均含量;煤中Au主要以矿物吸附态存在,载体矿物为黄铁矿和黏土矿物;17号煤层Au的物质来源为低温热液流体;在低温热液流体沿断裂带进入煤层的过程中,受到疏松多孔的煤层吸附而使Au元素发生沉淀,加之17号煤层沉积环境为较为封闭的浅海环境的综合作用而富集在煤中。Au的富集类型为深大断裂-热液作用富集型。     

Development of a Tellurium Speciation Study Using IC-ICP-MS on Soil Samples Taken from an Area Associated with the Storage,Processing, and Recovery of Electrowaste

The optimization and validation of a methodology for determining and extracting inorganic ionic Te(VI) and Te(IV) forms in easily-leached fractions of soil by Ion Chromatography-Inductively Coupled Plasma-Mass Spectrometry (IC-ICP-MS) were studied. In this paper, the total concentration of Te, pH, and red-ox potential were determined. Ions were successfully separated in 4 min on a Hamilton PRPX100 column with 0.002 mg/kg and 0.004 mg/kg limits of detection for Te(VI) and Te(IV), respectively. Soil samples were collected from areas subjected to the influence of an electrowaste processing and sorting plant. Sequential chemical extraction of soils showed that tellurium was bound mainly with sulphides, organic matter, and silicates. Optimization of soil extraction allowed 20% average extraction efficiency to be obtained, using 100 mM citric acid as the extractant. In the tested soil samples, both tellurium species were present. In most cases, the soils contained a reduced Te form, or the concentrations of both species were similar.