Red-shift in fluorescence emission of D–A type asymmetrical Zn(ii) complexes by extending the π–π stacking interaction

Abstract

Two D–A type asymmetrical Zn(II) coordination complexes, [ZnL¹(C₂H₅OH)] (1) (H₂L¹ = 2,4-di-tert-butyl-6-((E)-((2-((E)-(2-hydroxybenzylidene)amino)-4-nitrophenyl)imino)methyl)phenol) and [ZnL²(DMF)]·DMF (2) (H₂L² = 1-((E)-((2-((E)-(3,5-di-tert-butyl-2-hydroxybenzylidene)amino)-5-nitrophenyl)imino)methyl)naphthalen-2-ol), were designed, synthesized, and studied. Their fluorescence properties were comprehensively analysed based on their single-crystal structures. The results showed that the red-shift of fluorescence emission from complex 1 to complex 2 was successfully pushed via the strategy of extending the π–π stacking interaction.