CAJ | 학술논문

使用密度泛函理论(DFT)和 B3LYP/3-21G 基组，优化了24种取代吡啶类分子结构，发现吡啶环上氮原子的自然原子轨道电荷(NBO)值与其实验 pKa 值之间存在良好的线性关系(R=-0.62323)，比其原子核静电势电荷(ESP)值拟合的好。计算了12种未知 pKa 值的多取代吡啶化合物的 NBO 参数，代入拟合出的线性参数方程,发现与流行软件 ACD Lab 6.0预测得到的多取代吡啶的 pKa 值非常接近，最大偏差ΔpKa小于±0.07,新方法可以估测到pKa 值小数点后3位数。
사용밀도범함이론(DFT)화 B3LYP/3-21G 기조，우화료24충취대필정류분자결구，발현필정배상담원자적자연원자궤도전하(NBO)치여기실험 pKa 치지간존재량호적선성관계(R=-0.62323)，비기원자핵정전세전하(ESP)치의합적호。계산료12충미지 pKa 치적다취대필정화합물적 NBO 삼수，대입의합출적선성삼수방정,발현여류행연건 ACD Lab 6.0예측득도적다취대필정적 pKa 치비상접근，최대편차ΔpKa소우±0.07,신방법가이고측도pKa 치소수점후3위수。
The density functional theory DFT B3LYP/3-21G basis set were used to optimize the molecular structure of 24 kinds of pyridine and substituted pyridine, it’s found that the natural bond orbital (NBO) charge value of N atom on the pyridine ring has good linear relativity with its experimental pKb value, generally has better fitting result than its charge value of the electrostatic potential (ESP). NBO parameters of 12 substituted pyridine compounds with unknown pKb values were calculated, and they were substituted into the fitted linear parametric equation, it was found that the computed results were very close to substituted pyridine pKa value predicted by the popular software ACD-Labs 6.0.