The synthesis, characterization, and antibacterial activity of monooxidized selenoyl phosphinopyridylamine chelating ligand and its Fe(II) and Zn(II) metal complexes, together with the X-ray structures of the ligand and two unique Zn(II) metal complexes

The 2-(N-(diphenylphosphinoselenoyl)-2-(4-methylpyridyl) amine (4-CH3)C6H3N-2-NH(P(Se)Ph2) (1) ligand reacted with ZnX2(X = Cl, Br, I) and FeX2 (X = Cl, Br) in an equimolar ratio in refluxing CH3OH for 6 h, producing ZnX2{1-?2Se,Npy} (X = Cl(2), Br(3), I(4)) and FeX2{1-?2Se,Npy} (X = Cl(5), Br(6)) complexes, along with the byproduct ZnCl2[(4-CH3)C6H3N-2-NH(P(Se)Ph2)-?Npy]2 (7). Multinuclear NMR (1H, 13C, and 31P) together with infrared spectroscopy were employed to elucidate the characteristics of complexes 2?7. The molecular structures of compounds 1, 3, and 7 were determined by single-crystal X-ray diffraction. Complex 3 represents, to the best of our knowledge, the first structurally characterized Zn(II) complex of an amidopyridylphosphine selenide ligand featuring a ?2Se,Npy-bidentate coordination mode with a six-membered metallocyclic ring. Ligand 1 and its metal complexes 2?6 were evaluated for antibacterial activity using the disc diffusion method against selected microorganisms.