Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Department of Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200438, China.
Phys Chem Chem Phys. 2023 May 10;25(18):13198-13208. doi: 10.1039/d3cp01384g.
We report a joint experimental and theoretical study on the structures of gas-phase [TaO(CO)] ( = 2-5) ion-molecule complexes. Infrared photodissociation spectra of mass-selected [TaO(CO)] complexes were recorded in the frequency region from 2200 to 2450 cm and assigned through comparing with the simulated infrared spectra of energetically low-lying structures derived from quantum chemical calculations. With the increasing number of attached CO molecules, the larger clusters show significantly enhanced fragmentation efficiency and a strong band appears at around 2350 cm near the free CO antisymmetric stretching vibration band, indicating only a small perturbation of CO molecules on the secondary solvation sphere while higher frequency bands corresponding to the core structure remain largely unaffected. A core structure [TaO(CO)] is identified to which subsequent CO ligands are weakly attached and the most favorable cluster growth path is verified to proceed on the triplet potential energy surface higher in energy than that of ground states. Theoretical exploration reveals a two-state reactivity (TSR) scenario in which the energetically favored triplet transition state crosses over the singlet ground state to form a TaO core ion, providing new information on the cluster formation correlated with the reactivity of tantalum metal oxides towards CO.
我们报告了一个关于气相[TaO(CO)]（=2-5）离子-分子复合物结构的实验和理论联合研究。通过与从量子化学计算得出的低能结构的模拟红外光谱进行比较，在 2200 至 2450cm 的频率区域记录了质量选择的[TaO(CO)]复合物的红外光解离光谱，并进行了归属。随着附加 CO 分子数量的增加，较大的团簇表现出显著增强的碎片化效率，并且在自由 CO 反对称伸缩振动带附近的约 2350cm 处出现强带，表明 CO 分子对次级溶剂化球的小干扰，而对应于核心结构的较高频率带基本不受影响。鉴定出一个[TaO(CO)]的核心结构，随后的 CO 配体弱连接到该核心结构上，并且验证了最有利的团簇生长路径是在比基态能量更高的三重态势能表面上进行的。理论探索揭示了一个两态反应（TSR）情景，其中有利的三重态跃迁态越过单重态基态形成 TaO 核离子，为与铌金属氧化物对 CO 的反应性相关的团簇形成提供了新信息。
