Electrophilic substitution reactivity prediction of crown ether derivatives

Lithium is important for the world's economic development because it is the primary component of batteries. Crown ether derivatives are widely used for the separation and enrichment of lithium. The conformations of the designed crown ether were studied using molecular dynamics simulation. The electrophilic substitution reactivities of different conformations were analyzed by the conceptual density functional theory (CDFT) and the frontier molecular orbital theory (FMO). The analysis results show that the reactivity of the phenyl group can be increased by the π–π conjugation effect and bonded oxygen atoms. According to the reduced density gradient (RDG), the van der Waals interactions between the phenyl functional groups and methyl groups also benefit the reactivity. According to the global softness and nucleophilicity index, the reactivity of CE arm 1 − 03 is the highest. The condensed Fukui function, condensed local nucleophilicity index, and condensed local softness show that the electrophilic substitution reactivity of C benzene ring − 23 is the highest. C benzene ring − 23 also has the largest HOMO orbital composition. The analysis results of CDFT and FMO are consistent with each other, which suggests that the Koopmans approximation is suitable for the reactivity analysis of crown ether derivatives.