Thermochemical Data for Furan-based Monomer Candidates for Frontal Ring-Opening Metathesis Polymerization (FROMP)

This dataset includes 471 furan-based monomer candidates for frontal ring-opening metathesis polymerization (FROMP) and relevant thermochemistry as calculated with density functional theory (DFT). The monomer candidates were combinatorically enumerated using Diels-Alder reactions of furan derivatives as dienes and four types of dienophiles (alkenes, alkynes, allenes, and benzynes). Common substituents were enumerated for the dienophile classes, and methyl substitution on the diene was explored. We used the SMILES arbitrary target specification (SMARTS) language to produce monomers and ring-opened structures from diene and dienophile precursor SMILES, and we studied the ring-opening reaction using a homodesmotic equation with ethene. RDKit conformers were initially generated from SMILES, then optimized with GFN2-xTB. The two conformers lowest in energy were then optimized with DFT using the wb97x-D3 functional, def2-TZVP basis set, and def2/J auxiliary basis set. Gibbs free energy corrections were obtained through frequency calculations. Structures with imaginary frequencies below -50 cm^{-1} were excluded from this work, and smaller imaginary modes were flipped to be positive for free energy calculations. Modes below 50 cm^{-1} were treated with the modified rigid rotor approximation, and all thermochemical values were calculated at T=200C. The CSV file contains the monomer SMILES, the free energy of reaction for Diels-Alder addition (G_DA_200), and the enthalpy of the ring-opening reaction (H_RO_200). All energies are given in kcal/mol. An interactive HTML is also included to visualize the monomers in this dataset.

本数据集包含471种用于前沿开环易位聚合（frontal ring-opening metathesis polymerization, FROMP）的呋喃基单体候选物，以及通过密度泛函理论（density functional theory, DFT）计算得到的相关热化学数据。这些单体候选物以呋喃衍生物作为双烯体，结合四类亲双烯体（烯烃、炔烃、丙二烯与苯炔）的狄尔斯-阿尔德（Diels-Alder）反应，通过组合枚举方式生成；研究中针对各类亲双烯体枚举了常见取代基，并探究了双烯体上的甲基取代情况。我们采用SMILES任意目标规范（SMILES arbitrary target specification, SMARTS）语言，从双烯体与亲双烯体前体的SMILES（Simplified Molecular-Input Line-Entry System，简化分子线性输入规范）字符串生成单体及开环结构，并采用以乙烯为参照的同键型热化学方程研究开环反应。首先通过RDKit工具从SMILES字符串生成构象体，随后使用GFN2-xTB方法进行构象优化；选取能量最低的两个构象体，采用wb97x-D3泛函、def2-TZVP基组与def2/J辅助基组，通过DFT完成进一步优化。通过频率计算得到吉布斯自由能校正项：对于虚频低于-50 cm⁻¹的结构，本研究将其排除；对于虚频绝对值较小的振动模式，将其符号反转以用于自由能计算。对波数低于50 cm⁻¹的振动模式采用修正刚性转子近似处理，所有热化学数值均在T=200℃条件下计算得到。本数据集的CSV文件包含单体SMILES字符串、狄尔斯-阿尔德加成反应的自由能（G_DA_200）以及开环反应的焓变（H_RO_200），所有能量单位均为千卡每摩尔（kcal/mol）。此外还附带一份交互式HTML文件，用于可视化展示本数据集中的单体结构。