Temperature-Dependent Spin-Driven Dimerization Determines the Ultrafast Dynamics of a Copper(II)-Bound Tripyrrindione Radical
Temperature-Dependent Spin-Driven Dimerization Determines the Ultrafast Dynamics of a Copper(II)-Bound Tripyrrindione Radical
复制标题
温度依赖性自旋驱动二聚决定了铜 (II) 结合三吡啶二酮自由基的超快动力学
DOI：
10.1021/acs.jpclett.3c02726
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Huxter, Vanessa
中科院分区：
文献类型：
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作者：
Kumar, Anshu;Thompson, Benjamin;Gautam, Ritika;Tomat, Elisa;Huxter, Vanessa
自由基和其他开壳层分子在化学转化和氧化还原化学中起着核心作用。虽然自由基通常是高度反应性的，但稳定的自由基系统对于一系列潜在的应用是理想的，从材料化学和催化到自旋电子学和量子信息。在这里，我们研究了一个稳定的自由基系统的超快性质与温度相关的自旋可调性能。这种自由基复合物，铜（II）hexaethyl tripyrrin-1，14-二酮，容纳未成对电子本地化的铜金属中心和tripyrrolic配体。这种自由基分子中两个未成对电子的不寻常组合和高稳定性使得可切换的温度依赖性自旋耦合成为可能。在室温和77 K下收集了Cu（II）六乙基三吡咯啉-1，14-二酮的二维电子光谱测量。在室温下，分子以单体形式存在，并且具有短的皮秒寿命。在77 K时，分子以二聚体形式存在，由铁磁和反铁磁耦合介导。这种可逆的自旋驱动的二聚化改变了系统的光学性质，产生长寿命的激子态。
Radicals and other open-shell molecules play a central role in chemical transformations and redox chemistry. While radicals are often highly reactive, stable radical systems are desirable for a range of potential applications, ranging from materials chemistry and catalysis to spintronics and quantum information. Here we investigate the ultrafast properties of a stable radical system with temperature-dependent spin-tunable properties. This radical complex, Cu(II) hexaethyl tripyrrin-1,14-dione, accommodates unpaired electrons localized on both the copper metal center and the tripyrrolic ligand. The unusual combination of two unpaired electrons and high stability in this radical molecule enable switchable temperature-dependent spin coupling. Two-dimensional electronic spectroscopy measurements of Cu(II) hexaethyl tripyrrin-1,14-dione were collected at room temperature and at 77 K. At room temperature, the molecules are present as monomers and have short picosecond lifetimes. At 77 K, the molecules are present in a dimer form mediated by ferromagnetic and antiferromagnetic coupling. This reversible spin-driven dimerization changes the optical properties of the system, generating long-lived excitonic states.