The relationship between radical-scavenging rate constants (k) in an aprotic medium and thermodynamic parameters calculated by density functional theory (DFT) was investigated for 7 flavonols, which are myricetin (Myr), quercetin (Que), morin (Mor), kaempferol (Kae), 2′-methylquercetin (2′-MeQue), 5′-methylquercetin (5′-MeQue), and 2′,5′-dimethylquercetin (Me₂Que). The k values were determined for the reaction between the flavonols and galvinoxyl radical used as a reactivity model of reactive oxygen species in deaerated acetonitrile at 298 K. The energy difference values (D _HT, HT: hydrogen transfer) between the flavonols and the corresponding radicals, which equal to the relative O–H bond dissociation energies of the OH groups in the flavonols and ionisation potentials (IP) were calculated by DFT at the B3LYP/6-31++G(d) level with C-PCM solvation model parameterised for acetonitrile. Among the 7 flavonols used in this study, calculated IP values of 4 flavonols exhibited a linear correlation with log k, suggesting that the radical-scavenging reaction of these flavonols may proceed via an electron transfer as the rate determining step.

研究了7种黄酮醇的非质子介质中自由基清除速率常数（k）与通过密度泛函理论（DFT）计算的热力学参数之间的关系，这些黄酮醇是杨梅素（Myr），槲皮素（Que），茉莉（Mor），山，酚（Kae），2'-甲基槲皮素（2'-MeQue），5'-甲基槲皮素（5'-MeQue）和2'，5'-二甲基槲皮素（Me ₂ Que）。确定黄酮醇与加尔维诺尔自由基之间的反应的k值，该值用作298 K脱气乙腈中活性氧物种的反应性模型。能量差值（D _HT黄酮醇与相应基团之间的氢键（HT：氢转移）等于黄酮醇中OH基团的相对OH键解离能和电离势（IP）通过DFT在B3LYP / 6-31 + + G（d）含量，C-PCM溶剂化模型用于乙腈。在本研究中使用的7种黄酮醇中，4种黄酮醇的IP值与log k呈线性相关，表明这些黄酮醇的自由基清除反应可能通过电子转移作为速率确定步骤进行。