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使用半经验量子化学中的AM1方法、从头计算Hartree-Fock理论(在3-21G*水平)和密度泛函理论中的B3LYP方法(使用6-31G(d)基组),研究了尿酸分子的所有35种互变异构体。计算结果表明,三羰基互变异构体是所有异构体中能量最低的,其次为单羟基异构体和双羟基异构体,而含有三羟基的互变异构体相对能量最高。随着羟基数的增加, C-N键的平均键长从1.395逐渐缩短到1.351,而CC键的平均键长基本保持不变(1.400~1.406)。
Using the AM1 method in semi-empirical quantum chemistry, the calculations of the Hartree-Fock theory (at 3-21G * level) and the B3LYP method in density functional theory (using the 6-31G (d) basis set) All 35 tautomers. The calculated results show that the tricarbonyl tautomer is the lowest energy of all the isomers, followed by the monohydroxy isomers and the bishydroxy isomers, while the tautomers containing the trihydroxyls have the highest relative energy. With the increase of hydroxyl number, the average bond length of C-N bond gradually decreased from 1.395 to 1.351, while the average bond length of CC bond remained unchanged (1.400 ~ 1.406).