The paper compares the experimental FT-IR, 1H- and 13C-NMR spectra of isatoic anhydride (ISA) with the Hartree-Fock (HF) and Density Functional Theory (DFT) calculations using three different basis sets (6-31+G(d,p), 6-311+G(d,p), ccpVTZ). The best compatibility between the experimental and theoretical FT-IR spectrum was observed with the use of B3LYP/6-31+G(d,p) method for ISA. Furthermore, the theoretical1H- and 13C-NMR spectra interpreted by GIAO method depict that the DFT formalism, particularly the B3LYP/6-311+G(d,p) theory of level, gives an accurate description of the ISA experimental chemical shifts. The calculated structural data were also compared with experimental findings. The statistical regression analyses show that the B3LYP/6-31+G(d,p) method results in a correct description of the ISA crystallographic data. Moreover, the frontier molecular orbitals (FMOs), molecular electrostatic potential (MEP) map, and NBO atomic charges of the ISA have been discussed at B3LYP/6-31+G(d,p) theory of level. The FMO analysis were used to determine the charge transfer within ISA and some chemical descriptors such as ionization potential, electron affinity, chemical hardness, softness, chemical potential and electro negativity. The Nucleus-Independent Chemical Shifts (NICS) were also computed for ISA derivatives, 2-10. In the X: O and Y: S derivative, 4, sulphur substitution increases slightly the aromaticity of ISA skeleton.

中文翻译：

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Isatoic 酸酐的光谱、结构、芳香性和电子特性 - 实验和理论研究

本文使用三种不同的基组 (6-31+G(6-31+G( d,p), 6-311+G(d,p), ccpVTZ)。使用 ISA 的 B3LYP/6-31+G(d,p) 方法观察到实验和理论 FT-IR 光谱之间的最佳兼容性。此外，由 GIAO 方法解释的理论 1 H-和 13 C-NMR 谱描述了 DFT 形式主义，特别是 B3LYP/6-311+G(d,p) 能级理论，给出了 ISA 实验化学位移的准确描述。计算的结构数据也与实验结果进行了比较。统计回归分析表明 B3LYP/6-31+G(d,p) 方法可以正确描述 ISA 晶体学数据。而且，ISA 的前沿分子轨道 (FMO)、分子静电势 (MEP) 图和 NBO 原子电荷已在 B3LYP/6-31+G(d,p) 能级理论中进行了讨论。FMO 分析用于确定 ISA 内的电荷转移和一些化学描述符，如电离势、电子亲和性、化学硬度、柔软度、化学势和电负性。还计算了 ISA 衍生物的核独立化学位移 (NICS)，2-10。在X:O和Y:S衍生物中，4，硫取代略微增加了ISA骨架的芳香性。FMO 分析用于确定 ISA 内的电荷转移和一些化学描述符，如电离势、电子亲和性、化学硬度、柔软度、化学势和电负性。还计算了 ISA 衍生物的核独立化学位移 (NICS)，2-10。在X:O和Y:S衍生物中，4，硫取代略微增加了ISA骨架的芳香性。FMO 分析用于确定 ISA 内的电荷转移和一些化学描述符，如电离势、电子亲和性、化学硬度、柔软度、化学势和电负性。还计算了 ISA 衍生物的核独立化学位移 (NICS)，2-10。在X:O和Y:S衍生物中，4，硫取代略微增加了ISA骨架的芳香性。