“Property Prediction from Structural Differences”: II. Application to the molar diamagnetic susceptibilities of amino acids

Abstract

One of the main aims of the theoretical chemists is to introduce new and useful approaches for the estimation of chemical reactivity descriptors of Conceptual Density Functional Theory (CDFT) like absolute hardness, polarizability and magnetizability. In addition to providing results close to experimental results, the methods developed for this purpose must also be easily applicable to many molecular systems and easy to learn. “Property Prediction from Structural Differences” method proposed by one of the authors of this article is based on the idea that various properties of molecules can be easily calculated by taking the sum of the functional group contributions in the structure of the molecule. The most important thing in the applying of the method is the reliable determination of functional group contributions. In the present paper, using “Property Prediction from Structural Differences” method, we predicted the molar diamagnetic susceptibilities of amino acids with reasonably good accuracy. The computed values are in good agreement with experimental data and the results of previously introduced theoretical models. The reason why amino acids were especially preferred in the study is the lack of the molar diamagnetic susceptibility data of some amino acids in the literature. Additionally, to test whether a molar diamagnetic susceptibility based scale can be proposed for the calculation of any CDFT based reactivity descriptor, DFT computations were also performed for amino acid molecules. The relationships between parameters were evaluated in terms of the electronic structure rules like Maximum Hardness, Minimum Polarizability, Minimum Magnetizability and Minimum Electrophilicity Principles.