Li Wenqin, Maris Assimo, Melandri Sonia, Lesarri Alberto, Evangelisti Luca
Departamento de Química Física y Química Inorgánica, Facultad de Ciencias-I.U. CINQUIMA, Universidad de Valladolid, Paseo de Belén 7, 47011 Valladolid, Spain.
Department of Chemistry "G. Ciamician", University of Bologna, Via F. Selmi 2, 40126 Bologna, Italy.
Molecules. 2023 Dec 15;28(24):8111. doi: 10.3390/molecules28248111.
The molecular structure of a van der Waals-bonded complex involving 2,6-di-tert-butylphenol and a single argon atom has been determined through rotational spectroscopy. The experimentally derived structural parameters were compared to the outcomes of quantum chemical calculations that can accurately account for dispersive interactions in the cluster. The findings revealed a π-bound configuration for the complex, with the argon atom engaging the aromatic ring. The microwave spectrum reveals both fine and hyperfine tunneling components. The main spectral doubling is evident as two distinct clusters of lines, with an approximate separation of 179 MHz, attributed to the torsional motion associated with the hydroxyl group. Additionally, each component of this doublet further splits into three components, each with separations measuring less than 1 MHz. Investigation into intramolecular dynamics using a one-dimensional flexible model suggests that the main tunneling phenomenon originates from equivalent positions of the hydroxyl group. A double-minimum potential function with a barrier of 1000 (100) cm effectively describes this extensive amplitude motion. However, the three-fold fine structure, potentially linked to internal motions within the tert-butyl group, requires additional scrutiny for a comprehensive understanding.
通过转动光谱法确定了一种涉及2,6 -二叔丁基苯酚和单个氩原子的范德华键合复合物的分子结构。将实验得出的结构参数与能够精确解释团簇中色散相互作用的量子化学计算结果进行了比较。研究结果揭示了该复合物的π键构型，其中氩原子与芳环相互作用。微波光谱显示了精细和超精细隧穿成分。主要的光谱加倍表现为两个不同的谱线簇，近似间隔为179 MHz，这归因于与羟基相关的扭转运动。此外，这个双峰的每个成分进一步分裂为三个成分，每个成分的间隔小于1 MHz。使用一维柔性模型对分子内动力学的研究表明，主要的隧穿现象源于羟基的等效位置。一个具有1000(100) cm势垒的双势阱势函数有效地描述了这种大幅度运动。然而，可能与叔丁基内的内部运动相关的三重精细结构，需要进一步仔细研究以全面理解。
