Abstract Single crystal X-ray analysis reveals that the 9-(2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-en-1-yl)-3,3-dimethyl-2,3,4,9-tetrahydro-1H-xanthen-1-one, crystallizes in the centrosymmetric space group P21/c. In the crystal, molecules form as a dimer through a keto-enol type hydrogen-bonding pattern along with intermolecular C H⋯O interactions. The crystal structure of the title compound is further stabilized by intermolecular H⋯H interactions. Various intermolecular interactions present in the crystal structure are quantified by Hirshfeld surface analysis, PIXEL energy, NBO, AIM and DFT calculations. The energetics of the title compound is also compared with that of the two closely related analogs. Further, the vibrational modes of the interacting groups are characterized using both the experimental and simulated FT-IR and FT-Raman spectra. The experimental and calculated UV–visible spectra are compared and agree well. The time-dependent DFT spectra suggest that the ligand-to-ligand charge transfer within the molecule is responsible for the intense absorbance.

中文翻译：

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9-(2-羟基-4,4-二甲基-6-氧代环己-1-en-1-基)-3,3-二甲基-2,3,4,9-四氢-1H-xanthen-1-的研究一：晶体结构、AIM和NBO分析

摘要 单晶 X 射线分析表明 9-(2-羟基-4,4-二甲基-6-氧代环己-1-烯-1-基)-3,3-二甲基-2,3,4,9-四氢-1H-xanthen-1-one 在中心对称空间群 P21/c 中结晶。在晶体中，分子通过酮-烯醇型氢键模式以及分子间 CH⋯O 相互作用形成二聚体。标题化合物的晶体结构通过分子间 H⋯H 相互作用进一步稳定。晶体结构中存在的各种分子间相互作用通过 Hirshfeld 表面分析、像素能量、NBO、AIM 和 DFT 计算进行量化。标题化合物的能量学也与两个密切相关的类似物的能量学进行了比较。此外，相互作用组的振动模式使用实验和模拟 FT-IR 和 FT-拉曼光谱进行表征。实验和计算得出的紫外-可见光谱进行了比较并且非常吻合。与时间相关的 DFT 光谱表明分子内配体到配体的电荷转移是造成强吸光度的原因。