HA和HYP分子内质子传递模式差异的理论研究(英文)

The theoretical elucidation for different intramolecular proton transfer modes of hypocrellin A and hypericin

采用量子化学从头算的计算方法,研究了竹红菌素(HA)4种异构体发生分子内质子传递(IPT)的过程。结果表明,在竹红菌素分子内质子传递的过程中不会发生碳骨架结构的变化,这与之前文献中的猜测是不一致的,利用CIS和TD方法计算研究了竹红菌素激发态分子内质子传递的过程.结果表明,竹红菌素顺式结构的IPT过程是一个～10ps的瞬态过程,而竹红菌素反式结构的IPT过程则是一个～50～250ps的瞬态过程.根据计算结果我们对竹红菌素和金丝桃蒽酮分子内质子传递模式之间的差异做出了初步的解释.

In this paper, we present ab initio methods to study the four conformers of hypocrellin A （HA） and their intramolecular proton transfer （IPT/ products. The results indicates that the carbon skeleton transformation is less likely to take place in the IPT reaction of HA. It is in contrast with the assumptions in the preceding literatures. The results yielded by CIS and TD method indicate that the IPT reaction of parallel isomer of HA result in the - l 0 ps transient, while the 50 to 250 ps transient is due to the IPT reaction of versa isomer of HA. We have depicted the photophysical and photochemical process in figure. This mechanism results in the dramatically different IPT modes for hypericin and hypocrellin A.