Synthesis, characterization and X-ray crystal structures of [Ni(Me-sal)₂dpt] and [Ni(Me-sal)dpt]Cl

Two Ni(II) complexes, [Ni(Me-sal)₂dpt] (1) and [Ni(Me-sal)dpt]Cl (2), with penta- and tetradentate ligands ((H₂L¹)=H ₂(Me-sal)₂dpt=N,N-bis(α-methylsalicylidene) dipropylenetriamine and (HL²)=H(Me-sal)dpt=N-(α- methylesalicylidene)dipropylenetriamine) containing N₃O₂ and N₃O donor sets, respectively, have been synthesized and characterized by elemental analyses, FT-IR and UV-Vis spectroscopy. The green five coordinate complex [Ni(Me-sal)₂dpt] (1) forms on reaction of H₂(Me-sal)₂dpt with Ni^II(OAc)₂ • 4H₂O in boiling methanol, whereas at reflux temperature in ethanol the red diamagnetic [Ni(Me-sal)dpt]Cl (2) is formed on reaction of H₂(Me-sal)₂dpt with NiCl₂ • 6H ₂O. In the ligand (Me-sal)dpt one of the imine groups is hydrolysed resulting in a new tetradentate N₃O ligand. Complex (2) is also prepared in a higher yield by the direct reaction of H(Me-sal)dpt with NiCl ₂ • 6H₂O. The crystal and molecular structures of (1) and (2) were determined by X-ray crystallography. Complex (1) crystallizes in the monoclinic space group P2₁/c and complex (2) crystallizes in the triclinic space group P1̄. The coordination polyhedron about the Ni(II) center in complex (1) is best described as distorted trigonal bipyramidal and that of complex (2) as distorted square planar. The FT-IR and UV-Vis spectra of the complexes are also discussed.