A DFT study on the structural and optical properties and cation selectivities of some metal-coumarin-crown ether complexes

摘要

Macrocyclic ethers are well-known molecules because of theirhigh cation-binding capacities. They form stable complexes withalkaline and soil alkaline metals through strong oxygen bridges insolution. For enhanced optical properties, a new series of crownethers was synthesized with a coumarin ring fused to it. The effectsof the position of the coumarin ring, the type of the substituent onthe coumarin ring, and the size of the crown on the optical propertiesof the material were studied according to the density functionaltheory (DFT) method at the B3LYP/6-31g(d) level of theory in the gasphase as well as in the solvent medium. The ion selectivities ofdifferent coumarin-crown ether molecules were also studied bycalculating the metal-binding energies at the same level of theory.The excited-state electronic energies were calculated by using thetime-dependent density functional theory (TDDFT) method, and thetheoretical UV absorption spectra of the studied molecules wereplotted and compared to the experimental spectra if available.