Fluorine-Containing Polydentate Bis(heterocycles) Based on Di- and Triketone Analogs in the Synthesis of Zinc(II) Complexes

An approach to the synthesis of polydentate ligands in which the NH-pyrazole cycle is connected by the hydrazone group to the azine fragment (pyridine or pyrimidine) is developed. In the reactions with zinc(II) chloride, the synthesized bis(heterocyclic) compounds act as tridentate ligands with the formation of mononuclear complexes [Zn(L)Cl₂] (CIF files CCDC nos. 2352630 (I) and 2352631 (II)). The absolute quantum yield (QY = 12%) and fluorescence lifetime (τ = 2.64 ns) are measured for complex II containing the pyridine cycle as the azine fragment.