Heterometallic Zn^II?Ln^III?Zn^II Schiff Base Complexes with Linear or Bent Conformation-Synthesis, Crystal Structures, Luminescent and Magnetic Characterization.

ABSTRACT: A series of racemic, heteronuclear complexes [Zn?Nd(ac)?(HL)?]NO?·3H?O (1), [Zn?Sm(ac)?(HL)?]NO?·3CH?OH·0.3H?O (2), [Zn?Ln(ac)?(HL)?]NO?·5.33H?O (3?5) (where HL is the dideprotonated form of N,N'-bis(5-bromo-3-methoxysalicylidene)-1,3-diamino-2-propanol, ac = acetate ion, and Ln = Eu (3), Tb (4), Dy (5), respectively) with an achiral multisite coordination Schiff base ligand (H?L) were synthesized and characterized. The X-ray crystallography revealed that the chirality in complexes is centered at lanthanide(III) ions due to two vicinally located ?-acetato-bridging ligands. The presented crystals have isoskeletal coordination units but they crystallize in monoclinic (1, 2) or trigonal crystal systems (3?5) with slightly different conformation. In 1 and 2 the Zn^II?Ln^III?Zn^II coordination core is linear, whereas in isostructural crystals 3?5 the chiral coordination cores are bent and lie on a two-fold axis. The complexes 1, 3?5 show a blue emission attributed to the emission of the ligand. For Zn^II?Sm^III complex (2) the characteristic emission bands of f-f* transitions were observed. The magnetic properties for compounds 1, 4 and 5 are characteristic for the paramagnetism of the corresponding lanthanide(III) ions.

SUBMITTER: Miroslaw B 

PROVIDER: S-EPMC6099393 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature