SYNTHESIS AND CHARACTERIZATION OF A NOVEL BONDING TRINUCLEAR(Mo/Fe/Mo) COMPLEX (MoCl_4)_2·dppf

By the reaction of bidentate ligand 1,1'-bis(diphenylphosphino)-ferrocene (dppf) with MoCl_4(CH_3CN)_2, a novel bonding type complex (MoCl_4)2_· (dppf) was synthesized and characterized by elemental analyses, ^(31)p-NMR, IR and electronic spectra, TG and ICP-AES. Structure of the title complex was proposed.

Theoretical Study on the Electronic Structures of Small Ti_nN_m(n+m=5,6)Clusters

45 isomers of TinNm （n ＋ m = 5, 6） clusters, including linear, some planar and some stero configurations, have been predicted by density functional theory method. For five-atom clusters Ti3N2 and Ti2N3, the most stable structures are trigonal bipyramid in D3h symmetry, and for TiaN cluster, the isomer with one nitrogen atom occupying the center of quasi-tetrahedron is the most stable. In the isomers of Ti4N2 and Ti3N3, the planar networks are more stable, but for Ti2N4, the six-membered ring configuration is the most favorable. Most linear structures can form weak-strong bonds alternately with higher energy. As regards to planar structures, the more Ti-N bonds are formed, the more stable they will be; for stero closed polyhedral isomers, their energies are lower.

Quinones from Cordia species from 1972 to 2023:isolation,structural diversity and pharmacological activities

Plants of the genus Cordia(Boraginaceae family)are widely distributed in the tropical regions of America,Africa,and Asia.They are extensively used in folk medicine due to their rich medicinal properties.This review presents a comprehensive analysis of the isolation,structure,biogenesis,and biological properties of quinones from Cordia species reported from 1972 to 2023.Meroterpenoids were identified as the major quinones in most Cordia species and are reported as a chemotaxonomic markers of the Cordia.In addition to this property,quinones are reported to display a wider and broader spectrum of activities,are efficient scaffold in biological activity,compared to other classes of compounds reported in Cordia,hence our focus on the study of quinones reported from Cordia species.About 70 types of quinones have been isolated,while others have been identified by phytochemical screening or gas chromatography.Although the biosynthesis of quinones from Cordia species is not yet fully understood,previous reports suggest that they may be derived from geranyl pyrophosphate and an aromatic precursor unit,followed by oxidative cyclization of the allylic methyl group.Studies have demonstrated that quinones from this genus exhibit antifungal,larvicidal,antileishmanial,anti-inflammatory,antibiofilm,antimycobacterial,antioxidant,antimalarial,neuroinhibitory,and hemolytic activities.In addition,they have been shown to exhibit remarkable cytotoxic effects against several cancer cell lines which is likely related to their ability to inhibit electron transport as well as oxidative phosphorylation,and generate reactive oxygen species(ROS).Their biological activities indicate potential utility in the development of new drugs,especially as active components in drug-carrier systems,against a broad spectrum of pathogens and ailments.

Photocatalytic degradation of antibiotic sulfamethizole by visible light activated perovskite LaZnO_(3)

In thiswork,the perovskite LaZnO_(3) was synthesized via sol-gel method and applied for photocatalytic treatment of sulfamethizole(SMZ)antibiotics under visible light activation.SMZ was almost completely degraded(99.2%±0.3%)within 4 hr by photocatalyst LaZnO_(3) at the optimal dosage of 1.1 g/L,with amineralization proportion of 58.7%±0.4%.The efficient performance of LaZnO_(3) can be attributed to itswide-range light absorption and the appropriate energy band edge levels,which facilitate the formation of active agents such as·O_(2)^(−),h^(+),and·OH.The integration of RP-HPLC/Q-TOF-MS and DFT-based computational techniques revealed three degradation pathways of SMZ,which were initiated by the deamination reaction at the aniline ring,the breakdown of the sulfonamidemoieties,and a process known as Smile-type rearrangement and SO2 intrusion.Corresponding toxicity of SMZ and the intermediateswere analyzed by quantitative structure activity relationship(QSAR),indicating the effectiveness of LaZnO_(3)-based photocatalysis in preventing secondary pollution of the intermediates to the ecosystem during the degradation process.The visible-light-activated photocatalyst LaZnO_(3) exhibited efficient performance in the occurrence of inorganic anions and maintained high durability across multiple recycling tests,making it a promising candidate for practical antibiotic treatment.

Auto Machine Learning Assisted Preparation of Carboxylic Acid by TEMPO-Catalyzed Primary Alcohol Oxidation

Though alcohol oxidations were considered as well-established reactions,selecting productive conditions or predicting reaction yields for unseen alcohols remained as major challenges.Herein,an auto machine learning(ML)model for TEMPO-catalyzed oxida-tion of primary alcohols to the corresponding carboxylic acids is disclosed.A dataset of 3444 data,consisting of 282 primary alco-hols and 45 conditions,were generated using high-throughput experimentation(HTE).With the HTE data and 105 descriptors,a multi-label prediction was performed with AutoGluon(an open-source auto machine learning framework)and KNIME(an open-source data analytics platform).For the independent test of 240 reactions(a full matrix of 20 unseen alcohols and 12 condi-tions),AutoGluon with multi-label prediction for yield prediction(AGMP)gave excellent performance.For external test of 1308 re-actions(consisting of 84 alcohols and 45 conditions),AGMP still afforded good results with R2 as 0.767 and MAE as 4.9%.The model also revealed that the newly generated descriptor(Y/N,classification of the reaction reactivity)was the most relevant descriptor for yield prediction,offering a new perspective to integrate HTE and ML in organic synthesis.

Preconcentration and Determination of Chromium Species Using Octadecyl Silica Membrane Disks and Flame Atomic Absorption Spectrometry

A novel and selective method for the fast determination of trace amounts of chromium species in water samples has been developed. The procedure is based on the selective formation of chromium diethyldithiocarbamate complexes at different pH in the presence of Mn（Ⅱ） as an enhancement agent of chromium signals followed by elution with organic eluents and determination by atomic flame absorption spectrometry. The maximum capacity of the employed disks was found to be （396±3） pg and （376±2） pg for Cr（Ⅲ） and Cr（Ⅵ）, respectively. The detection limit of the proposed method is 49 and 43 ng·L^-1 for Cr（Ⅲ） and Cr（Ⅵ）, respectively. The proposed method was successfully applied for determination of chromium species Cr（Ⅲ） and Cr（Ⅵ） in different water samples.

The use of computational thermodynamic for yttrium recovery from rare earth elements-bearing residue

The rare earth elements are considered critical metals,due to the risk of supply interruption.The recycling of waste electrical and electronic equipment can be an alternative to supply the rare earth market.Several processes have been developed,and by aqueous media is the most prominent,which makes possible the extraction and separation of elements even in low concentration(traces).As an example of thermal processing,the use of thermodynamic simulations might benefit the metal extraction in hydrometallurgical processing.For this reason,the goal of this work is to evaluate the use of FactSage 7.2 software for the leaching of fluorescent lamp powders by sulfuric acid.The effect of concentration and temperature was evaluated.Results comprise that the thermodynamic software wellpredicted the solid phase formed in all residues of leaching experiments-gypsum was predicted by the software and identified in XRD analyses.It demonstrates that FactSage software can be explored for metals extraction in aqueous media,being important for trace-elements extraction.Yttrium extraction reaches up to 95%at 45℃using H_(2)SO_(4)2 mol/L.

Mechanism and selectivity of copper-catalyzed borocyanation of 1-aryl-1,3-butadienes:A computational study

Density functional theory calculations have been performed to investigate the copper-catalyzed borocyanation of 1-aryl-1,3-butadienes.The computations show that the regio-and enantioselectivity is determined by the borocupration step.The π-electron withdrawing aryl group at the C' atom makes the C4 atom more electrophilic than the other carbon atoms,which together with the steric repulsion around the forming C-B bond,re sults in the experimentally observed exclusive 4,3-regioselectivity.The origins of the enantioselectivity were attributed to the steric effect and π-π stacking interaction between the butadiene moiety and the ligand.

Nucleic acids analysis

Nucleic acids are natural biopolymers of nucleotides that store, encode, transmit and express genetic information, which play central roles in diverse cellular events and diseases in living things. The analysis of nucleic acids and nucleic acids-based analysis have been widely applied in biological studies, clinical diagnosis, environmental analysis, food safety and forensic analysis.During the past decades, the field of nucleic acids analysis has been rapidly advancing with many technological breakthroughs.In this review, we focus on the methods developed for analyzing nucleic acids, nucleic acids-based analysis, device for nucleic acids analysis, and applications of nucleic acids analysis. The representative strategies for the development of new nucleic acids analysis in this field are summarized, and key advantages and possible limitations are discussed. Finally, a brief perspective on existing challenges and further research development is provided.