A Sulfur Monoxide Surrogate Designed for the Synthesis of Sulfoxides and Sulfinamides**

Sulfur monoxide (SO) is a highly reactive species that cannot be isolated in bulk. However, SO can play a pivotal role as a fundamental building block in organic synthesis. Reported herein is the design and application of a sulfinylhydrazine reagent as an easily prepared sulfur monoxide surrogate. We show facile thermal SO transfer from this reagent to dienes where a reaction using a mechanistic probe suggests the generation of singlet SO. Combined with Grignard reagents and appropriate carbon or nitrogen electrophiles, the reagent serves as an effective “SO” donor to enable the one-pot, three-component synthesis of sulfoxides and sulfinamides.     

Cobalt-Porphyrin-Based Covalent Organic Frameworks with Donor-Acceptor Units as Photocatalysts for Carbon Dioxide Reduction

Covalent organic frameworks (COFs) have emerged as a promising platform for photocatalysts. Their crystalline porous nature allows comprehensive mechanistic studies of photocatalysis, which have revealed that their general photophysical parameters, such as light absorption ability, electronic band structure, and charge separation efficiency, can be conveniently tailored by structural modifications. However, further understanding of the relationship between structure-property-activity is required from the viewpoint of charge-carrier transport, because the charge-carrier property is closely related to alleviation of the excitonic effect. In the present study, COFs composed of a fixed cobalt (Co) porphyrin (Por) centered tetraamine as an acceptor unit with differently conjugated di-carbaldehyde based donor units, such as benzodithiophene (BDT), thienothiophene (TT), or phenyl (TA), were synthesized to form Co-Por-BDT, Co-Por-TT, or Co-Por-TA, respectively. Their photocatalytic activity for reducing carbon dioxide into carbon monoxide was in the order of Co-Por-BDT>Co-Por-TT>Co-Por-TA. The results indicated that the excitonic effect, associated with their charge-carrier densities and π-conjugation lengths, was a significant factor in photocatalysis performance.     

Synergistic Porosity and Charge Effects in a Supramolecular Porphyrin Cage Promote Efficient Photocatalytic CO2 Reduction**

We present a supramolecular approach to catalyzing photochemical CO₂ reduction through second-sphere porosity and charge effects. An iron porphyrin box ( PB ) bearing 24 cationic groups, FePB-2(P) , was made via post-synthetic modification of an alkyne-functionalized supramolecular synthon. FePB-2(P) promotes the photochemical CO₂ reduction reaction (CO₂RR) with 97 % selectivity for CO product, achieving turnover numbers (TON) exceeding 7000 and initial turnover frequencies (TOF_max) reaching 1400 min⁻¹. The cooperativity between porosity and charge results in a 41-fold increase in activity relative to the parent Fe tetraphenylporphyrin ( FeTPP ) catalyst, which is far greater than analogs that augment catalysis through porosity ( FePB-3(N ), 4-fold increase) or charge (Fe p-tetramethylanilinium porphyrin ( Fe-p-TMA ), 6-fold increase) alone. This work establishes that synergistic pendants in the secondary coordination sphere can be leveraged as a design element to augment catalysis at primary active sites within confined spaces.     

Indirect Spectrophotometric Method for Determination of Sulfur Dioxide

Abstract

An operationally inexpensive and satisfactory analytical procedure for sulfur dioxide is proposed. The reagent 3-methyl-1,2-cyclopentanodione dithiosemicarbazone has been used to determine trace amounts of sulfur dioxide indirectly using the reduction of Fe(III) to Fe(II) principle. In order to find the optimal conditions for SO₂ determination, properties of 3-Me-CPDT-Fe(II) complex such as its composition, stability and free energy change of formation have been determined. The best conditions for the complex formation such as standing time, pH, wavelength and the effect of interfering ions are described. The complex has been used with success in spectrophotometric determination of SO₂. The procedure can determine down to 0.63 μg and recoveries are better than 97.5%. The method is also suitable for determination of sulfur dioxide in the air provided that interfering gases such as H₂S and NO₂ are removed.     

时间域方法分析镍卟啉的共振拉曼强度与S2激发态结构

研究了入射光波长与S0→S2跃迁共振的情形下,卟啉镍配合物（NiP）的振动拉曼光谱。用时间域方法计算了NiP的共振拉曼强度和吸收光谱。结果表明,相对于基态,S2态NiP的分子构型沿着ν8和ν2简正坐标有较大的位移。这些简正坐标主要涉及卟啉环的CαCm键和CβCβ键伸缩运动,以及CαCmCα变角运动。与基态相比, S2态的CβCβ、 CαCm和CαN键分别增大0.27、 0.14、 0.07 pm,而CαCβ键则减小0.20 pm,与前人的赝势分子轨道计算（SPMO）结果相近。还从RR强度角度讨论了S2态的Jahn-Teller畸变。     

5,10,15,20-四(对氯苯基)卟啉羟基稀土配合物的光谱研究

研究了四(对氯苯基)卟啉及其羟基稀土配合物的紫外-可见光谱、红外光谱和拉曼光谱,对主要谱带进行了经验归属,讨论了中心离子对紫外光谱和共振拉曼光谱结构敏感带频率的影响.     

Carboxysome-Inspired Electrocatalysis using Enzymes for the Reduction of CO2 at Low Concentrations**

The electrolysis of dilute CO₂ streams suffers from low concentrations of dissolved substrate and its rapid depletion at the electrolyte-electrocatalyst interface. These limitations require first energy-intensive CO₂ capture and concentration, before electrolyzers can achieve acceptable performances. For direct electrocatalytic CO₂ reduction from low-concentration sources, we introduce a strategy that mimics the carboxysome in cyanobacteria by utilizing microcompartments with nanoconfined enzymes in a porous electrode. A carbonic anhydrase accelerates CO₂ hydration kinetics and minimizes substrate depletion by making all dissolved carbon available for utilization, while a highly efficient formate dehydrogenase reduces CO₂ cleanly to formate; down to even atmospheric concentrations of CO₂. This bio-inspired concept demonstrates that the carboxysome provides a viable blueprint for the reduction of low-concentration CO₂ streams to chemicals by using all forms of dissolved carbon.     

二氧化硫在化学资源化利用中的研究进展

二氧化硫(SO2)过量排放对自然环境造成了严重威胁,使得SO2的捕集和利用在工业生产中被广泛关注.目前,SO2的捕集技术已经相对成熟,对捕集后SO2的高附加值利用成为当前的热点问题.在SO2利用方法中,化学资源化利用由于具有原子经济性高、能耗低等优点,是实现SO2高附加值最有前景的方法之一.本文综述了SO2在无机反应中...     

Efficient Reduction of Nitroarenes to the Corresponding Anilines with Sulfur in Basic Media under Solvent-Free Conditions

Aromatic nitro compounds can be conveniently reduced to the corresponding primary amines in the presence of S 8 under solvent-free conditions in excellent yields. Alumina supported NaOH catalyses this transformation. Chemoselectivity was observed in the reduction of the nitro group in the presence of phenol, carboxylic acid, aldehyde, and benzyl halide groups.     

Supramolecular Enhancement of Electrochemical Nitrate Reduction Catalyzed by Cobalt Porphyrin Organic Cages for Ammonia Electrosynthesis in Water**

The electrochemical nitrate (NO₃⁻) reduction reaction (NO₃RR) to ammonia (NH₃) represents a sustainable approach for denitrification to balance global nitrogen cycles and an alternative to traditional thermal Haber-Bosch processes. Here, we present a supramolecular strategy for promoting NH₃ production in water from NO₃RR by integrating two-dimensional (2D) molecular cobalt porphyrin ( CoTPP ) units into a three-dimensional (3D) porous organic cage architecture. The porphyrin box CoPB-C8 enhances electrochemical active site exposure, facilitates substrate–catalyst interactions, and improves catalyst stability, leading to turnover numbers and frequencies for NH₃ production exceeding 200,000 and 56 s⁻¹, respectively. These values represent a 15-fold increase in NO₃RR activity and 200-mV improvement in overpotential for the 3D CoPB-C8 box structure compared to its 2D CoTPP counterpart. Synthetic tuning of peripheral alkyl substituents highlights the importance of supramolecular porosity and cavity size on electrochemical NO₃RR activity. These findings establish the incorporation of 2D molecular units into 3D confined space microenvironments as an effective supramolecular design strategy for enhancing electrocatalysis.     

A Systematic Approach for the Evaluation of Triethanolamine as a Possible Sulfur Dioxide Sorption Detector Coating

Abstract

A change in the vibrating frequency of a quartz crystal can be an accurate measurement of the mass change on the surface of the crystal. When coated with an absorbing compound, the subsequent frequency change indicates the sorption of a chemical species by the coating. An approach is proposed for evaluating potential crystal coatings and is. applied to the evaluation of Triethanolamine as a possible sulfur dioxide sorption detector coating.     

Understanding Electrochemical Reaction Mechanisms of Sulfur in All-Solid-State Batteries through Operando and Theoretical Studies **

Due to its outstanding safety and high energy density, all-solid-state lithium-sulfur batteries (ASLSBs) are considered as a potential future energy storage technology. The electrochemical reaction pathway in ASLSBs with inorganic solid-state electrolytes is different from Li-S batteries with liquid electrolytes, but the mechanism remains unclear. By combining operando Raman spectroscopy and ex situ X-ray absorption spectroscopy, we investigated the reaction mechanism of sulfur (S₈) in ASLSBs. Our results revealed that no Li₂S_8, Li₂S_6, and Li₂S₄ were formed, yet Li₂S₂ was detected. Furthermore, first-principles structural calculations were employed to disclose the formation energy of solid state Li₂S_n (1≤n≤8), in which Li₂S₂ was a metastable phase, consistent with experimental observations. Meanwhile, partial S₈ and Li₂S₂ remained at the full lithiation stage, suggesting incomplete reaction due to sluggish reaction kinetics in ASLSBs.     

Quantitative Construction of Boronic-Ester Linkages in Covalent Organic Frameworks for the Carbon Dioxide Reduction

Covalent organic frameworks (COFs) have been utilized for catalyzing the reduction of carbon dioxide (CO2RR) due to their atomic metal centers and controllable pore channels, which are facilitated by different covalent bonds. However, the exploration of boron-based linkages in these catalytic COFs has been limited owing to potential instability. Herein, we present the construction of boronic ester-linked COFs through nucleophilic substitution reactions in order to catalyze the CO₂RR. The inclusion of abundant fluorine atoms within the frameworks enhances their hydrophobicity and subsequently improves water tolerance and chemical stability of COFs. The content of boron atoms in the COF linkages was carefully controlled, with COFs featuring a higher density of boron atoms exhibiting increased electronic conductivity, enhanced reductive ability, and stronger binding affinity towards CO₂. Consequently, these COFs demonstrate improved activity and selectivity. The optimized COFs achieve the highest activity, achieving a turnover frequency of 1695.3 h⁻¹ and a CO selectivity of 95.0 % at −0.9 V. Operando synchrotron radiation measurements confirm the stability of Co (II) atoms as catalytically active sites. By successfully constructing boronic ester-linked COFs, we not only address potential instability concerns but also achieve exceptional catalytic performance for CO₂RR.     

Monitoring of Atmospheric Sulfur Dioxide by Fluorescence Monitoring System

A fluorescence monitoring system was used to measure gaseous sulfur dioxide at Taoyuan Agricultural Farm. A gas-diluting system and gas chromatograph equipped with a sulfur chemiluminescence detector used to audit the accuracy of diluted sulfur dioxide are described. The accuracy was ?8% and ?2%, respectively, for the preparation of 10 and 50 ppb SO₂ standard gas. The pattern of variation of SO₂ concentration at Taoyuan Agricultural Farm is reported. In summer at Taoyuan Agricultural Farm, the concentration of SO₂ varied with a pattern of night concentration (15-20 ppb) greater than that in the afternoon (0–2 ppb). Computer-analyzed wind trajectories in Taiwan for this pattern are reported.     

Coordinating the Edge Defects of Bismuth with Sulfur for Enhanced CO2 Electroreduction to Formate

Bismuth-based materials have been recognized as promising catalysts for the electrocatalytic CO₂ reduction reaction (ECO₂RR). However, they show poor selectivity due to competing hydrogen evolution reaction (HER). In this study, we have developed an edge defect modulation strategy for Bi by coordinating the edge defects of bismuth (Bi) with sulfur, to promote ECO₂RR selectivity and inhibit the competing HER. The prepared catalysts demonstrate excellent product selectivity, with a high HCOO⁻ Faraday efficiency of ≈95 % and an HCOO⁻ partial current of ≈250 mA cm⁻² under alkaline electrolytes. Density function theory calculations reveal that sulfur tends to bind to the Bi edge defects, reducing the coordination-unsaturated Bi sites (*H adsorption sites), and regulating the charge states of neighboring Bi sites to improve *OCHO adsorption. This work deepens our understanding of ECO₂RR mechanism on bismuth-based catalysts, guiding for the design of advanced ECO₂RR catalysts.     

单扫示波极谱法快速测定食品中二氧化硫

在0.025mol.L-1NH4OAc-HOAc(pH 5.0)溶液中,SO2吸附在滴汞电极上,于峰电位-0.66 V(vs.SCE)处产生灵敏的二阶导数极谱还原波,引入氯化十六烷基吡啶(CPC)后,峰电流I″p的灵敏度提高0.81倍,其I″p与SO2浓度在0.2-6.0 mg.L-1范围内呈线性关系,检出限为0.1 mg.L-1,S2-、NO2-、醛类及带色物质等无干扰。用于食品中SO2的测定,样品加标回收率为90.0%-114.0%,RSD为0.1%-5.2%。     

含氧气氛下预硫化钙钛矿LaCoO3上的CO还原SO2反应

 对钙钛矿LaCoO3在含氧气氛下的预硫化过程进行了研究．结果表明，在一定含氧气氛下硫化后的LaCoO3催化剂，用于含氧气氛下CO还原SO2反应具有很高的活性．XRD物相分析结果表明，硫化后的LaCoO3仍保持钙钛矿物相结构，但同时出现新的硫化物La2O2S和氧化物Co3O4物相．通过对硫化前后的催化剂进行O2－TPD和SO2－TPD分析，认为CO还原SO2反应机理可能是在一定的温度下，在钙钛矿LaCoO3上发生CO氧化燃烧反应，在硫化物La2O2S上发生CO还原SO2反应，两者相互促进．