Mn(OAc)3-Promoted Sulfonation-ipso-Cyclization Cascade via the SO3- Radical: The Synthesis of Spirocyclic Sulfonates.

A radical sulfonation-ipso-cyclization cascade promoted by Mn(OAc)3·2H2O using functionalized alkynes or alkenes and potassium metabisulfite (K2S2O5) is reported. A total of 30 spirocyclic sulfonates were synthesized under mild conditions. We also demonstrate a modular synthesis approach in multiple steps for the preparation of various azaspiro[4,5]-trienone-based sulfonamides and sulfonate esters.

Mn(OAc)3-Promoted Sulfonation-Cyclization Cascade via the SO3- Radical: The Synthesis of Heterocyclic Sulfonates.

Herein we reported a Mn(OAc)3·2H2O promoted radical sulfonation from functionalized alkenes and potassium metabisulfite (K2S2O5). The reaction realized the construction of oxindole, quinolinone, isoquinoline-1,3-dione, or benzoxazine structural fragments and the introduction of sulfonic moieties in one step. More than 50 heterocyclic sulfonates or their derivatives with various substituents were successfully prepared with high efficiency under mild conditions.

Homolytic Aromatic Sulfonation with K2S2O5 Promoted by a Combination of Mn(OAc)3·2H2O and HFIP.

Herein, we reported a so far unprecedented Mn(OAc)3·2H2O-promoted homolytic aromatic sulfonation. The reaction was performed under mild conditions with K2S2O5 employed as a green sulfonating reagent. Various arenes were successfully converted into desired sulfonic acids or sulfonates in high efficiency. Preliminary mechanistic studies demonstrated that the present reaction proceeds via a homolytic aromatic substitution-type mechanism involving an SO3- radical. The combination of Mn(OAc)3·2H2O and HFIP plays a crucial role.

Computer-aided design of microfluidic resistive network using circuit partition and CFD-based optimization and application in microalgae assessment for marine ecological toxicity.

We present an automatic design process for microfluidic dilution network towards marine ecological toxicity assessment on microalgae. Based on the hydraulic-electric circuit analogy, we defined an abstract specification using computer-aided designing system. Several approaches, especially circuit partition, were applied to minimize design effort. Computational fluid dynamics (CFD) simulation was exploited to convert the electrics specification to fabrication model. We automatically designed the combinational-mixing-serial dilution microfluidics to generate parallel stepwise gradients for mixing chemicals (binary/ternary/quaternary mixture) using the present algorithm. We critically discussed design rules and evaluated the microfluidic performance by colorimetric analysis. To examine whether these microfluidic chips can be used for toxicity test on microalgae, single and joint toxic effects of heavy metals (copper, mercury, zinc, and cadmium) were examined on line. In all cases, dose-related toxic responses were successfully detected. These results provided a solution for designing resistive network using circuit partition and CFD-based optimization and a route to develop a promising user-friendly alternative for microalgae bioassays as well as cell-based screening experiments in risk assessment.

Development of Microfluidic Dilution Network-Based System for Lab-on-a-Chip Microalgal Bioassays.

Because of the crucial ecological significance of microalgae, microalgal bioassays have become one of the most demanding tests from all classic aquatic toxicity tests in regulatory frameworks. However, conventional algal tests tend to be lab-intensive and time- and space-consuming, and they have not been utilized to their full potential for routine toxicity assessments. Microfluidics should be a user-friendly alternative. Particularly, dilution to generate gradients that are appropriate for screening experiments can be precisely attained by microfluidic network in a simple and cost-/time-/space-saving way. Here, we demonstrate a microfluidics series toward routine microalgal bioassays, including pretest, single, and joint toxicity test. The chip mainly consists of upstream dilution network (single serial dilution module (logarithmic/linear gradient generator) or multiple (binary/ternary/quaternary) mixing serial dilution module) and downstream diffusible culturing module. It allows the processes of chemical liquid dilution and diffusion, microscale microalgal culture, cell stimulation, and online screening to be integrated into a single device. Electric theorems with the aid of EDA (electronic design automation) simulation were innovatively introduced to minimize design effort for such systems. Using the device, microalgae were successfully cultured and stressed on-chip. The simple assay provides multibiological trait assessments of cell division rate, autofluorescence, esterase activity, and mobile capacity. This work showed promise in developing a high-throughput microfluidic platform for microalgal bioassays as well as lab-on-a-chip screening experiments in the cell-based quantitative assessment of environmental health risks.

An amperometric NO2 sensor based on La10Si5NbO27.5 electrolyte and nano-structured CuO sensing electrode.

A novel amperometric-type NO2 sensor based on La10Si5NbO27.5 (LSNO) electrolyte and nano-structured CuO sensing electrode was fabricated and tested. A bilayer LSNO electrolyte including both a dense layer and a porous layer was prepared by conventional solid state reaction method and screen-printing technology. The nano-structured CuO sensing electrode was in situ fabricated in LSNO porous layer by impregnating method. The composition and microstructure of the sample were characterized by XRD and SEM, respectively. The results showed that the CuO particles with diameters range of 200-500 nm were homogeneously dispersed on the LSNO backbone in porous layer. The sensor exhibited well sensing characteristics to NO2. The response current was almost linear to NO2 concentration in the range of 25-500 ppm at 600-800 °C. With increase of operating temperature, the sensitivity increased and reached 297 nA/ppm at 800 °C. The response currents toward NO2 were slightly affected by coexistent O2 (0-21 vol%) and CO2 (0-5 vol%).