CAJ | 학술논문

采用密度泛函理论(DFT)和 B3LYP/3-21G+（d）基组，优化了20种单取代苯酚酸分子结构，发现羟基上氧原子的自然原子轨道电荷(NBO-O)值与其实验 pKa 值之间存在良好的线性关系(R=-0.9736)，比其原子核拟合的静电势电荷(ESP-O)值相吻合的要好(R=-0.8998)。计算了20种典型未知 pKa 值取代苯酚酸的自然原子轨道电荷（NBO）参数，代入拟合的优势线性参数方程,发现与 ACD/Lab 6.0软件预测得到的取代苯酚酸 pKa 值较接近，其最大偏差?±0.200,且新方法可估测酚类分子的 pKa 值至小数点后三位数。
채용밀도범함이론(DFT)화 B3LYP/3-21G+（d）기조，우화료20충단취대분분산분자결구，발현간기상양원자적자연원자궤도전하(NBO-O)치여기실험 pKa 치지간존재량호적선성관계(R=-0.9736)，비기원자핵의합적정전세전하(ESP-O)치상문합적요호(R=-0.8998)。계산료20충전형미지 pKa 치취대분분산적자연원자궤도전하（NBO）삼수，대입의합적우세선성삼수방정,발현여 ACD/Lab 6.0연건예측득도적취대분분산 pKa 치교접근，기최대편차?±0.200,차신방법가고측분류분자적 pKa 치지소수점후삼위수。
By density functional theory DFT B3LYP/3-21+G(d) basis set , the molecular structures of 20 kinds of phenol acid and substituted phenol acid were optimized. It’s found that the natural atomic orbital charge value of O atom on the phenol acid has good linear relativity with its experimental pKa value, generally has better fitting result than its charge value of the electrostatic potential (ESP). NBO parameters of 20 substituted phenol acid compounds with unknown pKa values were calculated, they were substituted into the fitted linear parametric equation, and it was found that the computed results were very close to substituted benzoic acid pKa value predicted by the popular software ACD-Labs 6.0.