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Institute of Chemistry, Academia Sinica – Research

可分離之碳 (I) 物種：卡本陽離子自由基的結構與反應性

Isolated Carbon(I) Species Featuring a Carbone Cation Radical

Nature Synthesis 2025
Yi-Chen Chan, He-Xin Xiao, Lei Qin, Jiun-Shian Shen, Chen-Rui Yang, Glenn P. A. Yap, Wei-Min Ching, Wen-Ching Chen,* Yun-Wei Chiang,* Gernot Frenking,* Lili Zhao,* and Tiow-Gan Ong*

透過電子順磁共振光譜 (EPR)、X光單晶繞射與量子化學計算，成功釐清了[1-CDC]•+的結構與電子特性。

The structure and electronic properties of [1-CDC]•+ were elucidated by EPR spectroscopy, X-ray crystallography, and quantum chemical calculations.

Isolating a New Form of Carbon: A Breakthrough by Dr. Ong’s Team

Carbon is well known for its many allotropes, from diamonds and graphite to fullerenes and graphene. However, one of its rarest and most elusive forms is carbine—a highly reactive state in which carbon exhibits unusual electronic properties. Until recently, scientists have faced significant challenges in isolating and characterizing these transient carbon species, particularly a highly variant known as carbon(I) radicals. Dr. Tiow-Gan Ong’s research team at the Institute of Chemistry, Academia Sinica, has successfully synthesized and isolated a cationic carbon(I) radical species, [1-CDC]•+, by performing a single-electron transfer (SET) reaction between a carbodicarbene (CDC) and strongly electron-deficient 3-fluoronitrobenzene. The structure and electronic properties of [1-CDC]•+ were confirmed using electron paramagnetic resonance (EPR) spectroscopy, single crystal X-ray diffraction, and quantum chemical calculations. Reactivity studies reveal that this radical species effectively promotes various C-O and C-C cross-coupling reactions, particularly with electron-deficient aryl halides. These findings not only expand the understanding of carbon(I) radical chemistry but also open new avenues for radical methodologies in organic synthesis and catalysis.

This study was published on June 13, 2025, in Nature Synthesis. The research was led by Dr. Tiow-Gan Ong at the Institute of Chemistry, Academia Sinica, and carried out by Dr. Wen-Ching Chen and Dr. Yi-Chen Chan, as well as Ph.D. student He-Xin Xiao. The work was a collaborative effort with Professor Yun-Wei Chiang of the Department of Chemistry at National Tsing Hua University, Professor Gernot Frenking of Philipps-Universität Marburg, Germany, and Professor Lili Zhao of Nanjing University, China. Financial support was provided by Academia Sinica’s Thematic Research Program and the National Science and Technology Council’s Science Vanguard Research Program.

王朝諺研究團隊的重大突破：成功分離出一種全新形式的碳

碳是我們最熟悉的元素之一，它可以利用各種不同的形態存在，從鑽石、石墨、富勒烯到石墨烯。然而，碳還有一種極為罕見且反應性極高的形態-碳炔 (carbyne)，其中的碳具有非同尋常的電子狀態。這種形式的碳極難被穩定分離，尤其是其中一種被稱為碳(I)自由基的類型，長期以來讓科學家束手無策。本院化學所王朝諺研究團隊利用多年來自行發展的碳(0)物種-同碳雙碳烯 (carbodicarbene, CDC) 與具有強拉電子的3-氟硝基苯 (3-fluoronitrobenzene) 進行單電子轉移 (SET) 反應，成功合成並分離出碳(I)陽離子自由基[1-CDC]•+。並且藉由電子順磁光譜 (EPR)、X光單晶繞射及量子化學計算確認其結構與電子特性。進一步的反應性研究顯示了該自由基可促進多種C-O與C-C交叉偶聯反應，尤其對電子缺乏的芳香族鹵化物表現出相當優異的活性。此項發現不僅擴展了碳(I)自由基化學的研究領域，也為自由基應用於有機合成與催化反應提供嶄新的方向。

本研究於 2025 年 6 月 13 日發表於《自然-合成》(Nature Synthesis)，由本院化學所王朝諺研究員領導，實驗工作由陳文清博士、陳玉珍博士及博士生蕭禾鑫等人共同完成。研究亦與清大化學系江昀緯教授、德國馬堡大學 Gernot Frenking 教授及南京大學趙莉莉教授合作，攜手完成相關研究工作。經費來源包括本院「深耕計畫」與國科會「卓越領航計畫」。