新型膦胺配体羰基钌化合物的合成及其催化性能研究

以十二羰基三钌和o-PPh2C6H4NR2(R=H,Me)配体为原料,成功制备了三种新型羰基钌化合物(μ-o-PPh2-C6H4NH)Ru3(μ-H)(CO)9(2)、(o-PPh2C6H4NH)2Ru(CO)2(3)和(μ-o-PPh2C6H4NMe2)2Ru(CO)3(4).对这三个化合物进行了核磁共振和红外谱学、元素分析和X射线单晶衍射分析表征,并对这三个化合物进行了催化性能研究.化合物2和4可催化苯甲醛加氢反应生成苯甲醇,但是3没有催化活性.从实验角度阐述了膦胺配体钌催化剂的结构与性能关联,进一步探讨了加氢催化反应失活的可能原因.     

A novel signal-on fluorescent aptasensor for ochratoxin A detection based on RecJf exonuclease-induced signal amplification

This article describes a simple and homogeneous fluorescent aptasensor for the detection of ochratoxin A (OTA). With its high specificity and simplicity; RecJ_f exonuclease is used to cleave DNA strand of the FAM-aptamer/OTA complex and realize target recycling signal amplification. In order to avoid the loss of reaction system, magnetic beads (MBs) are added only once at the last experimental step. This proposed fluorescent aptasensor showed the higher sensitivity in the range of 0.1–100 ng/mL with LOD of 0.056 ng/mL, and the good selectivity against other interfering toxins. The feasibility of the prepared aptasensor was studied by detecting OTA in spiked liquor and cereal samples. The obtained average recoveries ranged from 92% to 115%. This study provides a promising application with convenience and rapidness in the aptasensor fabrication for food safety analysis.     

Visualization and In Situ Ablation of Intracellular Bacterial Pathogens through Metabolic Labeling

Protected by the host cells, the hidden intracellular bacteria are typically difficult to kill by common antibiotics and cannot be visualized without complex cellular pretreatments. Herein, we successfully developed a bacteria-metabolizable dual-functional probe TPEPy-d -Ala, which is based on d -alanine and a photosensitizer with aggregation-induced emission for fluorescence turn-on imaging of intracellular bacteria in living host cells and photodynamic ablation in situ. Once metabolically incorporated into bacterial peptidoglycan, the intramolecular motions of TPEPy-d -Ala are inhibited, leading to an enhanced fluorescent signal, which allows the clear visualization of the intracellular bacteria. Moreover, TPEPy-d -Ala can effectively ablate the labeled intracellular bacteria in situ owing to covalent ligation to peptidoglycan, yielding a low intracellular minimum inhibitory concentration (MIC) of 20±0.5 μg mL⁻¹, much more efficient than that of a commonly used antibiotic, vancomycin.     

Synthesis and biological evaluation of new mono naphthalimide platinum(IV) derivatives as antitumor agents with dual DNA damage mechanism

Naphthalimide has emerged as an interesting DNA intercalator and possessed attracting antitumor properties. In this context, naphthalimide group was linked to platinum(IV) core to construct a series of new mono naphthalimide platinum(IV) derivatives. The title compounds exert effective antitumor activities to the tested tumor cells lines in vitro, especially the one with propionyl chain displays comparable or even better bioactivities than platinum(II) reference drugs cisplatin and oxaliplatin. Moreover, the mono naphthalimide platinum(IV) derivative displays comparable tumor growth inhibitory competence against CT26 xenograft tumors in BALB/c mice in vivo without severe toxic effects in contrast to oxaliplatin. A dual DNA damage mechanism was proven for the title complex. Both naphthalimide ligand and the liberated platinum(II) moiety could generate DNA lesions to tumor cells synergistically and active the apoptotic pathway by up-regulating the expression of caspase 9 and caspase 3. Meanwhile, the conversion of platinum(II) drug into tetravalent form by incorporating naphthalimide moiety increases the uptake of platinum in whole cells and DNA remarkably. All these facts might be the factors for the title platinum(IV) complexes to overcome platinum(II) drug resistance. Additionally, the mono naphthalimide platinum(IV) complex could interact with human serum albumin by hydrogen bond and van der Waals force which would further influence their storage, transport and bioactivities.     

Whole-Cell Photoenzymatic Cascades to Synthesize Long-Chain Aliphatic Amines and Esters from Renewable Fatty Acids

Long-chain aliphatic amines such as (S,Z)-heptadec-9-en-7-amine and 9-aminoheptadecane were synthesized from ricinoleic acid and oleic acid, respectively, by whole-cell cascade reactions using the combination of an alcohol dehydrogenase (ADH) from Micrococcus luteus, an engineered amine transaminase from Vibrio fluvialis (Vf-ATA), and a photoactivated decarboxylase from Chlorella variabilis NC64A (Cv-FAP) in a one-pot process. In addition, long chain aliphatic esters such as 10-(heptanoyloxy)dec-8-ene and octylnonanoate were prepared from ricinoleic acid and oleic acid, respectively, by using the combination of the ADH, a Baeyer–Villiger monooxygenase variant from Pseudomonas putida KT2440, and the Cv-FAP. The target compounds were produced at rates of up to 37 U g⁻¹ dry cells with conversions up to 90 %. Therefore, this study contributes to the preparation of industrially relevant long-chain aliphatic chiral amines and esters from renewable fatty acid resources.     

氮掺杂碳点的制备及其对阿莫西林高灵敏检测

以天然物质石斛为原料,一步水热法合成高荧光量子产率的氮掺杂碳点(NCDs),通过透射电子显微镜(TEM)、X射线光电子能谱(XPS)、傅里叶变换红外光谱(FT-IR)、紫外-可见光吸收图谱(UV-Vis)及荧光光谱(PL)对合成的NCDs进行表征。 实验结果显示合成的NCDs发强烈的蓝色荧光,呈现为球形或准球形,均匀分散,尺寸范围在1~5 nm;其表面含有丰富的COOH、OH和NH₂等水溶性基团,最佳激发和发射波长分别为350和435 nm,且具有良好的发光稳定性。 通过测定,合成的NCDs的荧光量子产率高达29.19%。在pH=7.4的缓冲溶液中测定不同物质对NCDs的荧光影响,相同条件下发现只有阿莫西林能够对NCDs荧光进行明显猝灭,表明合成的NCDs可选择性的识别阿莫西林,通过NCDs的荧光强度变化构建一种可灵敏检测阿莫西林的传感器,检测线性范围为2.6~30 μmol/L,检出限为0.15 μmol/L。     

基于“1+2”模式的结构化学课程在线教学实践

Since the outbreak of novel coronavirus pneumonia (NCP) at the beginning of this year, Chinese government acted immediately and made some regulations to control the epidemic NCP and promote the recovery of society and industry including education. Chinese universities stayed on the online courses without suspension on teaching and learning. Herein, we report online teaching of structural chemistry course based on the teaching mode of online live broadcast platform, online course resources and management platforms ("1 + 2" mode). This may promote online teaching, and take advantage of online live broadcast and massive open online courses, which achieves good teaching and learning experiences on structural chemistry course.     

以9，10-双(咪唑基)蒽为配体的锌配合物的合成、晶体结构和荧光性质

以9,10-双（咪唑基）蒽（DIA）和硝酸锌为原料,分别与对苯二甲酸（H₂bdc）、二苯甲酮-4,4''-二羧酸（H₂cdc）、反式-1,4-环己二甲酸（H₂chdc）在溶剂热条件下反应,得到3个结构不同的配位聚合物[Zn₂（DIA）（bdc）₂]_n（1）、{[Zn（DIA）（cdc）]·H₂O}_n（2）和[Zn（DIA）（chdc）]_n（3）。对它们进行了X射线单晶衍射分析、元素分析、红外光谱分析和热重分析。单晶结构分析显示,配合物1是第一例拥有三维（4,7）-连接的{3².4.5².6}{3².4⁸.5⁴.6⁵.7²}₂拓扑结构;配合物2具有二维格子状结构,层与层之间通过O-H…O和π…π弱相互作用形成三维超分子结构;而配合物3具有二维两重贯穿的层状结构。结果说明有机羧酸的长度和刚柔性在配合物组装过程中起着非常重要的作用。此外,在室温下对3个配合物进行了荧光性质分析。     

Diphenyl cyclopropenone-centered polymers for site-specific CO-releasing and chain dissociation

The synthesis and stimuli-responsiveness of a diphenyl cyclopropenone(DPCP)-centered poly(methyl acrylate)(PMA)are presented.DPCP-centered PMA could release carbon monoxide(CO)upon UV light in a switched on-and-off manner.The CO-releasing process can be reported by the variations in photoluminescence spectra.In addition,DPCP moiety covalently embedded in the crosslinked polyurethane could also release CO under UV light.Of special,DPCP-centered PMA in solution was selectively dissociated at the phenol ester bond under the ultrasound,and a force-induced hydrolyzation reaction was revealed by D20 exchanging^1 H NMR spectra.The kinetic study reveals that small quantity of water could enhance the chain scission rate.This work provides a DPCP-centered polymer for sitespecific CO-releasing and chain dissociation.