一类新颖抗氧化剂的DFT研究

DFT STUDY ON A NEW CLASS OF ANTIOXIDANTS

理论设计了一类新型的抗氧化剂4，5-dihydroxyisoquinolines（DHIQS），并用密度泛函理论（density functional theory，DFT）在（RO）B3LYP／6—311＋G（2d，2p）／／B3LYP／6—31G（d）水平上研究了它们的结构=活性关系．研究表明，4，5-dihydrDxyisoquinoline（DHIQ）和活泼抗氧化剂1，8-naphthalenediol（DIOL）的活性相当，但是有更高的气态稳定性．对它的一系列对位取代衍生物研究表明。DHIQS比对等被取代的酚1，8-naphthalenediols（DIOLS）O—H键的解离能（O—HEBDE）仅高约2—2．5kCal·mol^-1，但是它们的电离势（EIP）比后者的高约8．9kCal·mol^-1，这意味着DHIQS和DIOLS有相近的反应活性，却比后者的稳定性高许多．因而，DHIQS是一类活性高而又有可以接受的气态稳定性的优良抗氧化剂．

A new class of antioxidants 4, 5 - .dihydroxyisoquinolines （DHIQS） is designed theoretically and the structure - activity relationship of them is investigated by density functional theory（ DFT） at the （RO）B3LYP/6- 311 ＋ G （2d,2p）//B31yp/6 - 31G（d） level. Study shows that the reactivity of 4,5 - dihydroxyisoquinoline is similar to that of the active antioxidant 1,8 - naphthalenediol （DIOL）, but the former has greater gas stability than that. of the latter. Furthermore,the EBDE of DHIQS are roughly 2 - 2.5 kCal· mol^-1 higher than those of the 1,8 - naphthalenediols （DIOLS）eounterparts,while the EIP values are about 8- 9 kCal· mol^-1 higher than those of the latter. This means that DHIQS possess similar rectivity toward chain - carrying peroxyl radicals as equivalently substituted phenols DIOLS, but greater stability to oxygen. Consequently, DHIQS are a new class of efficient antioxidants.