Lorpaiboon Wanutcha, Ho Junming
School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia.
J Phys Chem A. 2023 Sep 28;127(38):7943-7953. doi: 10.1021/acs.jpca.3c04750. Epub 2023 Sep 18.
In this study, 550 C-F bond dissociation energies (BDEs) of a variety of per- and polyfluoroalkyl substances (PFASs) obtained from high-level DLPNO-CCSD(T)/CBS calculations were used to assess the accuracy of contemporary density functional theory (DFT) and semiempirical methods. DLPNO-CCSD(T)/CBS gas phase C-F BDEs fall between 404.9-550.7 kJ mol and M06-2X and ωB97M-V in conjunction with the aug-cc-pVTZ basis set predicted BDEs closest to the benchmark level with a mean absolute deviation (MAD) of 7.3 and 8.3 kJ mol, respectively. It was observed that DFT prediction errors increase with the degree of fluorination and system size. As such, previous model chemistry recommendations based on smaller nonfluorinated systems may not be carried over to modeling the energetics of PFASs and related systems.
在本研究中，通过高水平的DLPNO-CCSD(T)/CBS计算获得的多种全氟和多氟烷基物质（PFASs）的550个C-F键解离能（BDEs）用于评估当代密度泛函理论（DFT）和半经验方法的准确性。DLPNO-CCSD(T)/CBS气相C-F BDEs在404.9 - 550.7 kJ/mol之间，M06-2X和ωB97M-V结合aug-cc-pVTZ基组预测的BDEs最接近基准水平，平均绝对偏差（MAD）分别为7.3和8.3 kJ/mol。据观察，DFT预测误差随氟化程度和体系大小而增加。因此，以前基于较小的非氟化体系的模型化学建议可能不适用于PFASs和相关体系的能量学建模。
