Synthesis, Luminescence Properties Of Complexes Based On Imidazole Derivatives

The derivatives of imidazloe, heterocyclic N-donor ligands, are bidentate or polydentate ligands in common. The aromatic rings of their metal complexes make possible theπ-πstacking and have good donor character, especially, in hydrogen bonding interactions. Thiocyanate is a perfect ligand with a polarizableπsystem and two different donor atoms nitrogen atom and sulfur atom. Either nitrogen or sulfur atom can coordinate to metals. Thiocyanate(SCN-) are versatile bridging agents. Their bonding in transition metal centers has generated varieties of structures. As a bridging ligand the SCN- can usually link a pair of metal centers in either an end-on or an end-to-end configuration. Also, SCN- can mediate both ferro and antiferromagnetic interactions between the paramagnetic metal ions depending on the bridging modes and the localized structural details.The complexes of imidazloe derivatives have potential and play an improtant role in optical materials, magnetic materials, chemical sensor, crystal structure, biological activity and catalysis. We synthesized complexes based on SCN- and imidazloe derivatives.Three novel imidazole derivatives, 2-(2'-pyridyl)-imidazole(L₁), 2-(2'-pyridyl) benzimidazole(L₂), 2,6-bis(benzimidazol-2-yl)-pyridine(L3) and their complexes have been synthesized and characterized. The structures of complexes 1( Ni(L₁)2(NCS)₂), complexes 2(Zn(L₂)₂(NCS)₂) and complexes 3 (MnL₃Cl₂) were determined by X-ray diffraction. The space groups of complex 1, 2 and 3 are C₂c/c, P-1 and P21/n, respectively. Zn(Ⅱ) , Ni(Ⅱ) ions are coordinated by four nitrogen atoms of ligands and two nitrogen atoms of thiocyanate. Mn(Ⅱ) ion are coordinated by three nitrogen atoms of ligand and two chlorine atoms. Single crystal X-ray studies on complex 1 and complex 3 indicated that the molecules of the complex 1 and 3 linked together through intermolecular N-H…S hydrogen bonds and N-H…Cl hydrogen bonds, respectively. In this paper, we report the preparation, crystal structure, Uv-vis spectrum, fluorescence spectrum and DFT calculation complex 1-3. Complex 1 to 3 have good property of luminescence.