Hetero-trinuclear Zn(II)-M(II) (M = Sr, Ba) complexes based on a mononuclear Zn(II) complex metallohost: syntheses, structures and fluorescence properties.

A new mononuclear Zn(II) complex, [ZnL(HOAc)] (1) (H2L = 6,6′-diethoxy-2,2′-[1,2-ethylenedioxybis(nitrilomethylidyne)]diphenol), was synthesized by reaction of H2L and Zn(II) acetate under solvothermal conditions. Complex1acts as a metallohost possessing a pentadentate O5donor. Complex1molecules bonded to one Sr(II) or Ba(II) form two new hetero-trinuclear complexes, [(ZnL)2M(OAc)2] (M = Sr (2), Ba (3)). In2and3, Zn(II) ions are 5-coordinate, but the Sr(II) or Ba(II) ion is 10-coordinate by fourμ-phenolic oxygens from two L2−units, four oxygens from four ethoxy groups and two oxygens from twoμ-acetato ligands. Furthermore,1–3exhibit blue emissions with the maximum emission wavelengthsλmax = 477, 500, and 471 nm when excited at 360 nm. [ABSTRACT FROM PUBLISHER]