Quantum Chemical Calculations on Binding Energy of Alkyl Substituted Crown Ethers with Sr~(2+)

摘要

Structures of Dibenzo-18-crown-6(DB 18C6), Di-methyl-dibenzo-18-crown-6(DMB18C6), Di-tert-butyl-dibenzo-18-crown-6(DTBB18C6), Di-tert-amyl-dibenzo-18-crown-6(DTAB1C6) and their complexes with strontium ion were optimized based upon DFT at B3LYP using 3-21G basis. The binding energy of crown ethers with Sr~(2+) was calculated according to the energy of optimal structures. The complex strength increased gradually from DB18C6 to DTAB18C6, which could be related to the changes of cavity size of crown ethers and electron density on the crown rings. Addition and extension of alkyl groups on DB18C6 could enhance the combination between crown and Sr~(2+) .