Jiang Junjie, Huang Longtian, Zhu Bifeng, Fan Wenbin, Wang Lina, Zhang Igor Ying, Fang Wei, Trabelsi Tarek, Francisco Joseph S, Zeng Xiaoqing
Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200433, China.
Department of Earth and Environment Science, University of Pennsylvania, Philadelphia, Pennsylvania, 19104-6243, USA.
Angew Chem Int Ed Engl. 2025 Jan 10;64(2):e202414456. doi: 10.1002/anie.202414456. Epub 2024 Nov 9.
Phosphorus mononitride (PN) is a carrier of phosphorus in the interstellar medium. As the simplest derivatives of PN, the radical species HPN⋅ and HNP⋅ have remained elusive. Herein, we report the generation, characterization, and photochemistry of HPN⋅ and HNP⋅ in N-matrix at 3 K. Specifically, HPN⋅ was formed as a weakly bonded complex with CO in the matrix by 254 nm photolysis of the novel phosphinyl radical HPNCO⋅. The ⋅NPH-CO complex is extremely unstable, as it undergoes spontaneous isomerization to the lower-energy isomer ⋅PNH-CO through fast quantum mechanical tunneling (QMT) with a half-life of 6.1 min at 3 K. Upon further irradiation at 254 nm, the reverse conversion of ⋅PNH-CO to ⋅NPH-CO along with dehydrogenation to yield PN was observed. The characterization ⋅NPH-CO and ⋅PNH-CO with matrix-isolation IR spectroscopy is supported by D, N, and C isotope labeling and quantum chemical calculations at the XYGJ-OS/AVTZ level of theory, and the mechanism by hydrogen atom tunneling is consistent with multidimensional instanton theory calculations.
一氮化磷（PN）是星际介质中磷的载体。作为PN最简单的衍生物，自由基物种HPN⋅和HNP⋅一直难以捉摸。在此，我们报告了在3 K的N基质中HPN⋅和HNP⋅的产生、表征及光化学性质。具体而言，通过新型膦酰基自由基HPNCO⋅的254 nm光解，HPN⋅在基质中作为与CO的弱键合络合物形成。⋅NPH-CO络合物极其不稳定，因为它会通过快速量子力学隧穿（QMT）自发异构化为能量较低的异构体⋅PNH-CO，在3 K时半衰期为6.1分钟。在254 nm处进一步辐照时，观察到⋅PNH-CO向⋅NPH-CO的反向转化以及脱氢生成PN。通过D、N和C同位素标记以及XYGJ-OS/AVTZ理论水平的量子化学计算，支持了用基质隔离红外光谱对⋅NPH-CO和⋅PNH-CO的表征，并且氢原子隧穿的机制与多维瞬子理论计算一致。
