Nickel(II) polypyridyl Complexes of 2,4,6-Tris(2-pyridyl)-1,3,5-triazine

The synthesis, purification, characterization, electrochemical properties, and fluorescence quenching of two new mononuclear Ni(II) complexes, [Ni(tptz)(CH3OH)Cl-2] (1) and [Ni(tptz)(2)](PF6)(2)center dot CH3CN (2), containing the ligand 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) are described. Solid state structures of both complexes have been determined by single crystal X-ray crystallography. In (1) and (2), the Ni(II) metal centers use the major coordination site of the tptz ligand and the coordination geometry around the Ni(II) is a distorted octahedron. The free tptz ligand has three emission bands that are assigned to the (1)(pi-pi (*) ) and (1)(n-pi (*) ) states. The fluorescence spectra of (1) and (2) show that the fluorescence quenching of the tptz fluorophore proceeds via an energy transfer process. Magnetic susceptibility data derived from paramagnetic NMR revealed effective magnetic moments of 2.75 mu (B) for (1), and 2.91 mu (B) for (2) at room temperature. Cyclic voltammetry of (1) shows that the Ni(III/II) reduction couple is quasi-reversible whereas in complex (2), the Ni(II/I) couple indicates an electrochemical (EC) mechanism. The synthesis, purification, characterization, electrochemical properties, and fluorescence quenching of two new mononuclear Ni(II) complexes, [Ni(tptz)(CH3OH)Cl-2] and [Ni(tptz)(2)](PF6)(2)center dot CH3CN, containing the ligand 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) are described. Solid state structures of both complexes have been determined by single crystal X-ray crystallography. .