7─羟基喹啉与甲醇、乙醇形成1：2桥式氢键化合物的AM1法研究

AM1 Study on the 1 : 2 Bridged Complexes of 7-hydroxyquinoline with Methanol and Ethanol

利用半经验ＡＭ１方法计算了基态与第一激发态７－羟基喹啉的两种异构体及其与甲醇等溶济分子形成１：２桥式氢键化合物的结构与稳定性。在基态，烯醇式结构比酮式结构稳定；而在第一激发态酮式比烯醇式稳定。１：２桥式氢键的形成使得酮式能量降低比烯醇式多。烯醇式１：２桥式氢键化合物呈交叉式结构，酮式１：２桥式氢键化合物呈折叠式结构，激发态的形成对氢键结构影响不大。在７－羟基喹啉羟基（或羰基）的邻位和间位引入取代基后，对喹啉环和桥式氢键结构的影响均不明显。

AM1 method has been used to study the structures and stability of the 1: 2-bridged enol and keto forms of 7-hydroxyquinoline (7-HQ) with methanol and ethanol solvents in the ground and first excited states. The 1: 2-bridged enol form is more stable than the keto form in ground state; but in the first excited state the stability of the two forms reversed. The formation of the 1: 2-bridged hydrogen-bonded complexes makes the keto form lower more energy than the enol form. The results also show that the 1: 2-bridged enol form has a crossed 10-member-ring structure, and the 1: 2-bridged keto form has a folded 10-member-ring structure. Both the excitation of the complexes and the substitution of NO2 and OCH3 groups for the meta and ortho hydrogen atoms of the hydroxy (carbonyl)group in 7-HQ have little influence on the hydrogen-bonded ring.