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

Abstract

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 ([C 40H 56N 14Ni(H 2O)(CH 3OH)](ClO 4) 2(CH 3OH) 2) with moderate zero-field splitting (ZFS) axial distortion parameter D/ k B = 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 ([C 40H 56N 14Ni(NCS) 2](CHCl) 3) with an extended parameter D/ k B = 8.80 K. The analysis of the structural and magnetic properties of complexes 1 and 2 led to the design of dinuclear complex 3 ([C 40H 56N 14NiN 3] 2(ClO 4) 2(CH 3OH) 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 (N 3) 2 structure. The magnetic behavior of complex 3 reveals ferromagnetic coupling interactions characterized by J/ k B = 23.25 K, D 1/ k B = 7.90 K, D 2/ k B = 0.54 K.