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Abstract：
The selection of a \"perfect tool\" for the theoretical determination of acid-base dissociation constants (Ka) is still puzzling. Recently, we developed a user-friendly model exploiting CAM-B3LYP for determining pKa with impressive reliability. Herein, a new challenge is faced, examining a panel of functionals belonging to different rungs of the \"Jacob\'s ladder\" organization, which classifies functionals according to their level of theory. Specifically, meta-generalized gradient approximations (GGAs), hybrid-GGAs, and the more complex range-separated hybrid (RSH)-GGAs were investigated in predicting the pKa of differently substituted carboxylic acids. Therefore, CAM-B3LYP, WB97XD, B3PW91, PBE1PBE, PBEPBE and TPSSTPSS were used, with 6-311G+(d,p) as the basis set and the solvation model based on density (SMD). CAM-B3LYP showed the lowest mean absolute error value (MAE = 0.23) with relatively high processing time. PBE1PBE and B3PW91 provided satisfactory predictions (MAE = 0.34 and 0.38, respectively) with moderate computational time cost, while PBEPBE, TPSSTPSS and WB97XD led to unreliable results (MAE > 1). These findings validate the reliability of our model in predicting carboxylic acids pKa, with MAE well below 0.5 units, using a simplistic theoretical level and a low-cost computational approach.
摘要：
选择用于理论测定酸碱解离常数（Ka）的“完美工具”仍然令人困惑。最近,我们开发了一个用户友好的模型，利用CAM-B3LYP确定pKa具有令人印象深刻的可靠性。在这里，面临新的挑战,检查属于“雅各布的梯子”组织的不同梯级的一组功能，根据功能的理论水平对功能进行分类。具体来说,元广义梯度近似(GGAs)，混合GGAs，在预测不同取代羧酸的pKa时，研究了更复杂的范围分离杂化（RSH）-GGAs。因此,CAM-B3LYP,WB97XD,B3PW91,PBE1PBE,使用PBEPBE和TPSSTPSS，与6-311G+（d，P)作为基础集和基于密度(SMD)的溶剂化模型。CAM-B3LYP显示出最低的平均绝对误差值(MAE=0.23),具有相对较高的处理时间。PBE1PBE和B3PW91提供了令人满意的预测（MAE分别为0.34和0.38），计算时间成本适中，而PBEPBE,TPSSTPSS和WB97XD导致不可靠的结果(MAE>1)。这些发现验证了我们的模型在预测羧酸pKa，MAE远低于0.5个单位，使用简单的理论水平和低成本的计算方法。
