酸碱软硬度在成矿理论研究中的应用

以Ｌｅｗｉｓ酸碱理论为基础发展起来的酸碱软硬度的理论广泛地应用于解释各类化学现象，包括类质同象置换，共生，应用于评价和预测化学反应极为简便和实用。然而，软硬酸碱度原理的理论基础尚在不断地充实之中。本文简要讨论了硫化物矿物的酸碱势标度，用酸碱软硬度理论解释了矿物的类质同象现象，是应用酸碱软硬度理论揭示和完善矿物成矿理论的一种偿试。

酸碱软硬度的标度

根据Klopman G的微扰理论,利用元素原子的电子组态变化,离子半径及元素电负性等参数,给出了Lewis酸碱软硬标度的新经验公式,其计算过程简便,参数易得,计算结果与Pearson分类能较好地吻合。

酸碱软硬度的理论研究

Pearson 从大量的实验事实归纳出的软硬酸碱原理广泛地应用于解释许多化学现象,还应用于评价和预料化学反应,极为简便、实用。然而,软硬酸碱原理的理论基础尚在不断地充实之中。近来微扰理论和密度泛函理论研究的结果表明:软硬酸碱能成功地描述化学反应,有明确的物理意义。现在(?)将定域硬度(或软度)和分子的化学活性定量地联系了起来。本文指出了酸碱软硬度键参数与物质性质定量研究的美好前景。

模糊模式识别法标度软硬酸碱理论中碱的软硬度

引进影响化合物酸碱度的两个主要参数a与b,分别为电负性(X)与电荷半径比(Z2/R),从而建立了化合物分类判别的模糊数学模型。该模型可以比较好地判别化合物的化学键型,分辨率达到了96%。

Application of the HSAB principle for the quantitative analysis of nucleophilicity/basicity of organic compounds with lone-pair electrons

Based on the density functional theory,we described here a method to investigate the quantitative relationship between nucleophilicity/basicity and HSAB-theory-based properties of compounds with lone-pair electrons.Descriptors including global softness,Fukui function,local softness and local mulliken charge were calculated at SVWN/DN~* level of DFT with PC Spartan Pro.Nucleophilicity and basicity of 28 selected compounds were classified based on intensity.BP algorithm of artificial neural network(ANN) was employed to study the relationship between the descriptors and nucleophilicity/basicity.Cross-validation was carried out to avoid the over-fitting in training of ANN.A BP network was trained to quantify the relationship between HSAB-theory-based properties and nucleophilicity/basicity of compounds with lone-pair electrons.The results show that the prediction based on the network matches with the experimental results well.The local softness and Fukui function have a better relationship with nucleophilicity and local mulliken charge than with the basicity.The trained BP network could be utilized for predicting the nucleophilicity/basicity of compounds or functional groups with lone-pair electrons.