Trinuclear and mononuclear nickel(II) complexes incorporating tridentate 2-[(pyridine-2-ylimine)methyl]phenol ligand: Syntheses, crystal structures and magnetic properties

[Ni3(pymp)4(pya)2](NO3)2(CH3OH)2 (1), [Ni3(pymp)4(pya)2]Cl2(CH3OH)2 (2) and [Ni(pymp)2(py)2] (3) (Hpymp = 2-[(pyridine-2-ylimine)methyl]phenol, pya = pyridin-2-amine and py = pyridine) were synthesized and characterized. Crystal structures reveal that 1 and 2 contain phenoxo-bridged and N–C–N bridged linear trinuclear cores (uncommon for trinuclear nickel complexes), with the central Ni(II) being coordinated in a NiO4N2 fashion while the two terminal Ni(II) atoms adopt a NiO2N4 coordination mode. Two novel coordination modes of Hpymp ligand are presented in 1 and 2. Complex 3 displays a NiO2N4 coordination mode with the Ni(II) in a slightly distorted octahedral environment. Magnetic measurements of 1 indicated that the Ni centers are ferromagnetically coupled.