当代化工
噹代化工
당대화공
CONTEMPORARY CHEMICAL INDUSTRY
2014年
3期
324-326
,共3页
密度泛函理论方法%取代苯甲酸%自然原子轨道电荷%pKa
密度汎函理論方法%取代苯甲痠%自然原子軌道電荷%pKa
밀도범함이론방법%취대분갑산%자연원자궤도전하%pKa
Density functional theory%Substituted benzoic acid%Natural atomic orbitals charge%PKa
采用密度泛函理论(DFT)和 B3LYP/3-21+G(d)基组，优化了21种单取代苯甲酸分子结构，发现羧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)，比其原子核静电势电荷(ESP-O)值拟合的要好。计算了20种典型未知 pKa 值的单和多取代苯甲酸化合物的 NBO参数，代入拟合出的优势线性参数方程,发现其预测值与流行软件 ACD Lab 6.0预测得到的单和多取代苯甲酸的 pKa 值非常接近，最大偏差ΔpKa小于±0.03,且新方法可以估测到pKa 值小数点后3位数。
採用密度汎函理論(DFT)和 B3LYP/3-21+G(d)基組，優化瞭21種單取代苯甲痠分子結構，髮現羧基上氧原子的自然原子軌道電荷(NBO-O)值與其實驗 pKa 值之間存在良好的線性關繫(R=-0.9736)，比其原子覈靜電勢電荷(ESP-O)值擬閤的要好。計算瞭20種典型未知 pKa 值的單和多取代苯甲痠化閤物的 NBO參數，代入擬閤齣的優勢線性參數方程,髮現其預測值與流行軟件 ACD Lab 6.0預測得到的單和多取代苯甲痠的 pKa 值非常接近，最大偏差ΔpKa小于±0.03,且新方法可以估測到pKa 值小數點後3位數。
채용밀도범함이론(DFT)화 B3LYP/3-21+G(d)기조，우화료21충단취대분갑산분자결구，발현최기상양원자적자연원자궤도전하(NBO-O)치여기실험 pKa 치지간존재량호적선성관계(R=-0.9736)，비기원자핵정전세전하(ESP-O)치의합적요호。계산료20충전형미지 pKa 치적단화다취대분갑산화합물적 NBO삼수，대입의합출적우세선성삼수방정,발현기예측치여류행연건 ACD Lab 6.0예측득도적단화다취대분갑산적 pKa 치비상접근，최대편차ΔpKa소우±0.03,차신방법가이고측도pKa 치소수점후3위수。
Density functional theory DFT B3LYP/3-21+G(d) basis set were used to optimize the molecular structure of 21 kinds of benzoic acid and substituted benzoic acid, it’s found that the natural atomic orbital charge value of O atom on the benzoic 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 benzoic acid compounds with unknown pKa values were calculated, they were substituted into the fitted linear parametric equation, 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.
