Abstract The structural, spectroscopic and electronic features of the 6-(Chloromethyl)uracil (6CMU) have been characterized by using single crystal X-ray diffraction (XRD), 1H and 13C NMR, UV–Vis. and vibrational (FT-IR and Raman) spectroscopies. The classical geometry analyses of intermolecular interactions, which were performed on the basis of experimental crystal structure, have been supported by Hirshfeld surface analysis. Theoretical molecular geometry optimization parameters (bond lengths and angles), vibrational wavenumbers, proton and carbon NMR chemical shifts, UV–Vis. parameters (wavelengths, excitation energies, oscillator strength) and the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies have been calculated using density functional theory (DFT/B3LYP) quantum chemical method with 6–311++G (d,p) basis set to compare with the experimental results. Assignments of the vibrational wavenumbers have been carried out by Potential Energy Distribution (PED) analyses by using VEDA 4 software. UV–Vis. electronic absorption parameters, HOMO-LUMO analyses, Natural Bond Orbital (NBO) results and Molecular Electrostatic Potential (MEP) surface of 6CMU have been studied to explicate electronic transitions, intramolecular charge transfer and interaction sites in the molecule. The computed vibrational wavenumbers, NMR chemical shifts and UV–Vis. parameters have been in good agreement with the corresponding experimental data and literature.

中文翻译：

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6-(氯甲基)尿嘧啶的晶体结构、光谱和电子特征

摘要 6-(氯甲基)尿嘧啶 (6CMU) 的结构、光谱和电子特征已通过单晶 X 射线衍射 (XRD)、1H 和 13C NMR、UV-Vis 进行表征。和振动（FT-IR 和拉曼）光谱。在实验晶体结构的基础上进行的分子间相互作用的经典几何分析已得到 Hirshfeld 表面分析的支持。理论分子几何优化参数（键长和角度）、振动波数、质子和碳核磁共振化学位移、UV-Vis。参数（波长、激发能量、振荡器强度）和最高占据分子轨道（HOMO）和最低未占据分子轨道（LUMO）能量已使用密度泛函理论（DFT / B3LYP）量子化学方法计算，以6-311++ G（d，p）为基础设置与实验结果进行比较。振动波数的分配已通过使用 VEDA 4 软件的势能分布 (PED) 分析进行。紫外-可见。已经研究了 6CMU 的电子吸收参数、HOMO-LUMO 分析、自然键轨道 (NBO) 结果和分子静电势 (MEP) 表面，以解释分子中的电子跃迁、分子内电荷转移和相互作用位点。计算出的振动波数、NMR 化学位移和 UV-Vis。