Theoretical Study of Some Dield-Alder Reactions Using Density Functional Theory

The section of density functional theory that studies the quantum descriptors for handlingthe chemical reactivity of chemical components is well known as chemical reactivity densityfunctional theory (CR-DFT). Some of such descriptors are electronic chemical potential [1],global and local chemical hardness [2] and softness, electrophilicity index [3] and etc. The mainproblem in determining these indexes for chemical compounds is the lack of explicit functionfor electronic energy function in terms of the number of electrons and the external potential.Therefore some operational definitions of electronic chemical potential and chemical absolutehardness were reported in literatures. Recently Noorizadeh and Parsa [4] proposed the newMorse-like function for the electronic energy function of atomic and molecular system andthen calculated the electronic chemical potential and molecular chemical hardness indexes asthe first and second derivatives of the electronic energy function with respect to electronnumbers at constant external potential respectively.In the present work the Morse-like function applied to calculate these reactivity indexesfor investigating of the regioselectivity for some Diels-Alder cycloadition reactions todetermine and predict the main product of these reactions. The results show that in manycases the global hardnesses and global electrophilicities which derived from this newapproach, with maximum hardness principle (MHP) [5] and minimum electrophilicity principle(MEP)[6] can predict the major regioisomer products of Diels-Alder reactions correctly.

Keywords:

Density Functional Theory , Chemical Hardness , Morse-like Function , Electrophilicity Index