Synthesis, structural and luminescence studies of some zinc complexes having pyrazole and carboxylate ligands

Some zinc (II) complexes having formula [Zn(PziPr2H)(μ-PziPr2)(RCOO)]2 [(PziPr2H = 3,5-diisopropylpyrazole, RCOO− = carboxylate ligands with R is CH3 for 1, CF3 for 2, CH3(CH2)2 for 3, CH3(CH2)4 for 4 and CH3(CH2)5 for 5] were prepared and structurally characterized by different techniques including single crystal X-ray. The X-ray studies suggested that all these complexes are centrosymmetric dinuclear with tetrahedral geometry around each zinc center. The pyrazole ligand is coordinated in both terminal as well as a bridging fashion whereas the carboxylates behave as monodentate ligand. All the complexes show hydrogen bonding between hydrogen atom of pyrazole (N–H of terminal pyrazole) and nonbonded oxygen atom of carboxylate. Out of these complexes only 5 [Zn(PziPr2H)(μ-PziPr2)(CH3(CH2)5COO)]2 exhibited emission at room temperature.