硫辛酸类似物清除自由基活性的理论研究

Theoretical study on the free radical scavenging of lipoic acid analogues

为寻找高效抗氧化剂,本文采用量子化学方法,在"万能抗氧化剂"硫辛酸的结构基础上,设计、研究了16种不同碳链长度、不同成环原子类型、不同成环原子个数的硫辛酸类似物。以X-Y键的解离焓DBE和分子电离势IP为理论指标评价了这些化合物的抗氧化性。研究结果表明,成环原子数目、分子碳链长度、成环原子类型对BDE和IP产生不同程度的影响。其中,成环原子数目、分子碳链长度对抗氧化性影响较小,成环原子类型影响较大。硫辛酸的含硒类似物有可能成为新型的高效抗氧化剂。HOMO能级顺序与IP数值预测的抗氧化性的顺序一致,较好的阐明了结构对硫辛酸类物质抗氧化性的影响。计算结果为新型抗氧化剂的设计、合成提供了理论支撑。

In order to discover effective antioxidants,a systematic quantum chemistry study at density functional level was conducted on 16 lipoic acid analogues varied in total carbon numbers,nature of atoms X,Y and ring size.The X-Y bond dissociation enthalpy（BDE）and ionization potential（IP）were selected as theoretical indexes to evaluate the ability of free radical scavenging.The results showed that,those factors had different influence on BDE and IP.The nature of atoms X and Y had greater impact on the antioxidant activity than other factors.The selenium derivatives of lipoic acid were the candidates for new antioxidants.The HOMO energy gave the same antioxidant activity subsequence as indicated by IP value.The results showed a clear relationship between structure-antioxidant activity relationship,which was useful for the designing and synthesis of new antioxidants.