This contribution sets out to compute thermochemical and geometrical parameters of the complete series of chlorinated isomers of thiophene based on the accurate chemistry model of CBS-QB3. Herein, we compute standard entropies, standard enthalpies of formation, standard Gibbs free energies of formation, and heat capacities. Our calculated enthalpy values agree with available limited experimental values. The DFT-based reactivity descriptors were used to elucidate the site selectivity for the chlorination sequence of thiophene. The relative preference for chlorination was found to be in accord with the thermodynamic stability trends inferred based on the H scale. Calculated Fukui indices predict a chlorination sequence to ensue as follows: 2-chloro → 2,5-dichloro → 2,3,5-trichloro → 2,3,4,5-tetrachlorothiophene.

中文翻译：

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噻吩氯化物的热化学参数及理论研究

该贡献旨在根据 CBS-QB3 的准确化学模型计算噻吩的全系列氯化异构体的热化学和几何参数。在此，我们计算标准熵、标准生成焓、标准吉布斯生成自由能和热容。我们计算出的焓值与可用的有限实验值一致。基于 DFT 的反应性描述符用于阐明噻吩氯化序列的位点选择性。发现对氯化的相对偏好与基于 H 标度推断的热力学稳定性趋势一致。计算得出的福井指数预测氯化顺序如下：2-氯 → 2,5-二氯 → 2,3,5-三氯 → 2,3,4,5-四氯噻吩。