Theoretical design on a new double functional device of 2,2′‐bipyridine‐embedded N ‐(9‐pyrenyl methyl)aza‐15‐crown‐5

Theoretical design on a new molecular switch and fluorescent chemosensor double functional device of aza‐crown ether (2,2′‐dipyridine‐embedded N ‐(9‐anthraceneyl(pyrenyl)methyl)aza‐15‐crown‐5) was explored. The interactions between ligands and a series of alkaline earth metal cations (Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ ) were investigated. The fully optimized geometry structures of the free ligands ( L 1, L 2 ) and their metal cation complexes ( L 1 /M 2+ , L 2 /M 2+ ) were calculated with the B3LYP/6‐31G(d) method. The natural bond orbital analysis, which is based on optimized geometric structures, was used to explore the interaction of L 1 /M 2+ , L 2 /M 2+ molecules. The absorption spectra of L 1, L 2 , L 1 /M 2+ , and L 2 /M 2+ , and their excited states were studied by time‐dependent density functional theory. A new type molecular device L 2 (2,2′‐dipyridine‐embedded N ‐(9‐pyrenyl methyl)aza‐15‐crown‐5) is designed, which not only has the selectivity for Sr 2+ , and construct allosteric switch, but also has fluorescent sensor performance.