The Influence of Coordination Mode Differences on the Structural Diversity and Fluorescence Properties of Zn(II)/Cd(II) Schiff Base Complexes

Four metal complexes, 1 : Zn 2 Cl 2 L 2 , 2 : Zn 2 (CH 3 OO) 2 L 2 ·MeCN, 3 : Zn(NO 3 ) 2 HL , and 4 : CdCl 2 HL , are obtained by coordinating the flexible Schiff base ligand 4‐amino‐N′‐(di(pyridin‐2‐yl)methylene)benzohydrazide (abbreviated as HL ) with the Zn(II) and Cd(II). X‐Ray single crystal diffraction confirms that the four complexes 1 – 4 employ two different coordination modes. Moreover, the structures of complexes 1 and 2 are accompanied by deproton behavior, and these structural differences not only increase the fluorescence quantum yield but also produce a redshift in fluorescence emission. Time‐dependent density functional theory calculations confirm that these performance changes are related to the coordination mode and coordination environment. This work not only constructs the four fluorescent complexes, but also further deepens the understanding of the structure–activity relationship between the structure of the complexes and the fluorescence properties.