Ancillary ligands assisted self-assembly of metal organic frameworks: Synthesis, crystal structures and photophysical properties of two Zn(II) complexes containing in-situ formed tetrazole ligands

Solvothermal reactions of 4-cyanobenzoic acid (HL1), NaN3, hydrated ZnSO4 in the presence of ancillary ligands pyrazine or 4,4′-dimethylbipyridine (Me2bpy) afforded a 3-D coordination polymer [Zn(L2)(H2O)]n (1) and a 2-D layer [Zn3(Me2bpy)(N3)2(L2)]n (2) (L2 = 4-tetrazolylbenzenecarboxylate), respectively in which pyrazine significantly alters the self-assembly of 1 and the coordination of Me2bpy in 2 leads to a novel linearly trinuclear [Zn3(Me2bpy)2(N3)2]4 + subunit functioning as a secondary building block (SUB). Their crystal structures have been determined by X-ray crystallography and solid state luminescent properties have been measured at room temperature.