Structural and magnetic behavior of mono- and dinuclear nickel (II) complexes of N,N′-bis-(3,5-dipiperidin-1-yl-[2,4,6]triazin-1-yl)-pyridin-2-ylmethyl-ethane-1,2-diamine

Reaction of nickel (II) perchlorate with the ligand N,N′-bis-(3,5-dipiperidin-1-yl-[2,4,6]triazin-1-yl)-pyridin-2-ylmethyl-ethane-1,2-diamine yields an octahedral Ni(II) high-spin complex 1 ([C40H56N14Ni(H2O)(CH3OH)](ClO4)2(CH3OH)2) with moderate zero-field splitting (ZFS) axial distortion parameter D/kB = 5.37 K. The ligand contributes a N4 donor set; the remaining two coordinating positions are occupied by coordinating solvents molecules. Exchange of the coordinating solvents molecules in complex 1 to thiocyanate moieties leads to formation of complex 2 ([C40H56N14Ni(NCS)2](CHCl)3) with an extended parameter D/kB = 8.80 K. The analysis of the structural and magnetic properties of complexes 1 and 2 led to the design of dinuclear complex 3 ([C40H56N14NiN3]2(ClO4)2(CH3OH)2), where two azido groups were utilized as bridging ligands. The double azido bridges in complex 3 cross each other to form a rarely observed non-coplanar (N3)2 structure. The magnetic behavior of complex 3 reveals ferromagnetic coupling interactions characterized by J/kB = 23.25 K, D1/kB = 7.90 K, D2/kB = 0.54 K.