A new route for the synthesis of 2,4-bis(2-pyridyl)-6-(pyridyl)pyrimidines: Synthesis and characterization of Co(II), Ni(II) complexes of 2,4,6-tris(2-pyridyl)pyrimidine

Using 2-acetylpyridine, sodium hydroxide and 2-cyanopyridine, 2,4,6-tris(2-pyridyl)pyrimidine (L1) was synthesized in good yield. Similarly, 2,4-bis(2-pyridyl)-6-(3-pyridyl)pyrimidine (L2) and 2,4-bis(2-pyridyl)-6-(4-pyridyl)pyrimidine (L3) were also synthesized by using respective acetylpyridine. 2-Acetylpyridine reacted with sodium hydroxide to produce 2-oxo-2-(2-pyridyl)-1-ethanide, which behaves as a nucleophile towards 2-cyanopyridine. All three pyrimidines are potential multidentate ligand and by using L1 complexes of composition [Ni(L1)(H2O)(3)](NO3)(2)center dot 4H(2)O (1), [Ni(L1)(2)](NO3)(2)center dot 2H(2)O (2) and [Co(L1)(2)](NO3)(2)center dot 1.5H(2)O (3) were isolated and structurally characterized. In 1-3, L1 behaves as a tridentate pincer type ligand, DFT calculations performed on L1-L3 indicate that energy difference between HOMO and LUMO is 4.544, 4.643 and 4.533 eV respectively.