Jiangsu Normal University

A regioselective (4+2) cyclization of 2,3-indolyldimethanols with 3-vinylindoles was established under the catalysis of Brønsted acids, leading to the efficient construction of structurally diverse bisindole-fused six-membered rings in overall good yields (71%-95%) and with excellent regioselectivity. Moreover, a preliminary investigation on the asymmetric version of this reaction using chiral Brønsted acids was also conducted, demonstrating its potential for enantioselective synthesis of chiral bisindole-fused six-membered rings. This work not only offers a practical approach for synthesizing bisindole-fused rings, but also gives a valuable example of highly regioselective cyclization involving 2,3-indolyldimethanols, thereby significantly enriching the chemistry of 2,3-indolyldimethanols.

ABSTRACT Lithium dendrite formation and low ionic conductivity of solid polymer electrolytes (SPEs) are the main challenges that plague the long cycle life and capacity retention of lithium‐metal batteries. To address these challenges, poly(crown ether piperidinium) (PCEP)/poly(ethylene oxide) (PEO) based SPEs with synergistic regulation of cation−anion functions are designed and prepared. The crown ether moieties within PCEP enable coordination with Li + , reducing the Li + coordination number and enhancing the ionic conductivity of SPEs to 4.2 × 10 −4 S cm −1 at 60°C. Concurrently, piperidinium units effectively immobilize TFSI − ions through electrostatic adsorption, resulting in an elevated Li + transference number (0.7) and a concomitant reduction in lithium dendrite growth. Consequently, a coin cell using a PCEP‐based SPE with a lithium iron phosphate cathode displayed a high cycle life of 2000 cycles at 1.0C with a commendable final discharge capacity of 117.9 mAh g −1 , corresponding to 79.4% capacity retention. Furthermore, lithium−sulfur coin cells utilizing PCEP‐based SPEs exhibit a specific discharge capacity of 671.8 mAh g −1 after 80 cycles at 0.2C, corresponding to 80.7% of the initial capacity, outperforming SPEs without PCEP. This research work introduces a synergistic cation−anion regulation strategy for the advancement of solid‐state energy conversion/storage systems.

Coal mining activities have demonstrated substantial environmental contamination, posed severe risks and impacted to the surrounding soil ecosystems. However, the effects of a single crack particularly during its initial stage of formation caused by deep mining-induced cracks, which fundamentally modify soil structure and affect PTE concentrations near coal mining, are poorly understood. Understanding this redistribution is essential for assessing environmental risks and developing remediation strategies. Soil samples were collected along primary crack zones in abandoned subsidence affected soils in Shandong Province, China, and analyzed using ICP-MS for seven PTEs to evaluate geo-accumulation index, spatial distribution and potential health risk. The result showed that concentrations of As, Ni, Cr, and Zn exceeded Shandong background levels by 1.32, 1.14, 1.07, and 1.05 times, respectively, indicating anthropogenic enrichment. The Soil was slightly contaminated by As, Ni, and Cu based on geo-accumulation index. Spatial analysis presented that all PTEs had strong spatial similarity, revealing a high concentration in the deep main crack, whereas Hg exhibits a distinct distribution behavior. Except mercury, statistical correlation among PTEs indicating common geochemical pathways. Health risk assessment of PTEs showed that children face exposure risks, particularly from oral ingestion of As with risk of 2.06 × 10-5. These findings demonstrate that subsidence-related cracking plays a critical role in modifying distribution of potential toxic elements in abandoned soils and elevated health risk of arsenic for children, providing essential knowledge for risk mitigation and land management strategies in mining-disturbed regions.