Argentivorous molecules with chromophores: dependence of their fluorescence intensities on the distance between a donor and an acceptor

Abstract

We have prepared new argentivorous molecules (L² and L³) having different linker lengths between cyclen and anthracene units. The structures of Ag⁺ complexes with the new ligands were investigated in solution and solid states. The silver(I) ion-induced ¹H NMR and UV-vis spectral changes of L² and L³ showed the presence of 1 : 1 complexes. The solid-state structures of the Ag⁺ complexes with L² and L³ are stable 1 : 1 complexes because four aromatic side-arms wrap the Ag⁺ incorporated in the cyclen unit. A photo-induced electron transfer (PET) effect that depends on the length of the linker connecting the nitrogen atoms of cyclen to the chromophore is also investigated. The result indicates a linear (log) correlation between the donor–chromophore average distances of the optimized structures calculated by DFT calculations and fluorescence intensities (log I), and the PET effect becomes ineffective at about 12 Å in this system.