Multiyne chains chelating osmium via three metal-carbon σ bonds

碳是最常见的元素之一，是有机化学、金属有机化学中的最基本元素。有趣的是，尽管碳在配位化学中同样广泛存在，其很少作为配位原子，多齿配合物中的配位原子通常为N/O/P/S等杂原子；配位原子均为碳的碳多齿配合物的构筑是个挑战。尽管如此，与大多数杂原子配位多齿配合物可由多齿配体与金属原子直接螯合制备不同，此前报道的碳龙配合物只能通过金属杂环衍生化获得。最近，夏海平教授课题组提出了通过配位化学方法构筑碳龙配合物的新思路——由多齿碳链配体或配体前体直接螯合金属制备碳龙配合物。他们设计合成了一类全新的链状多炔化合物，其可在室温、空气氛下与市售金属配合物OsCl2(PPh3)3、甚至无机盐K2OsCl6反应，一锅法克级制备碳龙配合物，简化了碳龙配合物的合成路线，大大降低了碳龙化学的研究门槛。该方法具有可拓展性，通过碳龙的变化可合成结构多样的碳龙配合物，进一步丰富了碳龙配合物的种类；此外，碳龙配合物金属品种的拓展工作也正在进行中。该工作首次实现了由有机碳链直接螯合金属中心构筑三齿及三齿以上碳多齿螯合物，深化和拓展了人们对碳配位能力的认识。 该研究工作在夏海平教授指导下完成，第一作者为厦门大学化学化工学院博士后卓庆德。卓庆德，本科毕业于南昌大学，2010年考入厦门大学化学化工学院有机化学专业攻读硕士，师从夏海平教授和张弘副教授。2012年提前攻博，期间主要致力于新型金属有机化合物的合成、反应性及性能研究。2016年3月进入化学工程与技术博士后流动站从事博士后研究，合作导师夏海平教授。目前，已发表第一作者论文4篇；申请中国发明专利2项；PCT国际专利1项；并获得中国博士后科学基金（60批）的资助。【Abstract】Although the formation of metal–carbon σ bonds is a fundamental principle in organometallic chemistry, the direct bonding of one organic molecule with one metal center to generate more than two metal–carbon σ bonds remains a challenge. Herein, we report an aromaticity-driven method whereby multiyne chains are used to construct three metal–carbon σ bonds in a one-pot reaction under mild conditions. In this method, multiyne chains act as ligand precursors capable of chelating an osmium center to yield planar metallapolycycles, which exhibit aromaticity and good stability. The direct assembly of various multiyne chains with commercially available metal complexes or even simple metal salts provides a convenient and efficient strategy for constructing all carbon-ligated chelates on the gram scale.This research was supported by the National Natural Science Foundation of China (Nos. 21490573 and 21332002) and Project funded by China Postdoctoral Science Foundation (No. 2016M602069). 研究工作得到国家自然科学基金重大项目（21490573 ）和重点项目（21332002），以及中国博士后科学基金（2016M602069）的资助

Determination of the number of ψ(3686) events taken at BESIII

The number of ψ(3686) events collected by the BESIII detector during the 2021 run period is determined to be (2259.3±11.1)×106 by counting inclusive ψ(3686) hadronic events. The uncertainty is systematic and the statistical uncertainty is negligible. Meanwhile, the numbers of ψ(3686) events collected during the 2009 and 2012 run periods are updated to be (107.7±0.6)×106 and (345.4±2.6)×106, respectively. Both numbers are consistent with the previous measurements within one standard deviation. The total number of ψ(3686) events in the three data samples is (2712.4±14.3)×10^

Prediction of Energy Resolution in the JUNO Experiment

International audienceThis paper presents the energy resolution study in the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The study reveals an energy resolution of 2.95% at 1 MeV. Furthermore, the study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data taking. Moreover, it provides a guideline in comprehending the energy resolution characteristics of liquid scintillator-based detectors