One Ferromagnetic and Two Antiferromagnetic Dinuclear Nickel(II) Complexes Derived from a Tridentate N,N,O-Donor Schiff Base Ligand: A Density Functional Study of Magnetic Coupling

摘要: Three new dinuclear NiII complexes, [Ni2L2(NO3)2] (1), [Ni2L2(NO2)2] (2), and [Ni2L2(CH3COO)2(H2O)] (3), have been synthesized by using a tridentate Schiff base ligand, 2-({[3-(dimethylamino)propyl]imino}methyl)phenol (HL), along with nitrate, nitrite, or acetate ion, respectively, as co-ligand. These three complexes were characterized spectral analysis, X-ray crystallography, variable-temperature magnetic susceptibility measurements. The structural analyses revealed that the ions are coordinated deprotonated chelating possess distorted octahedral geometry in all complexes. Complexes 1 2 two di-μ2-phenoxido-bridged species which nitrate nitrite act co-ligands. However, complex 3, anion is monodentate, an additional water bridge present μ2-phenoxido bridges making face-sharing bi-octahedron. Magnetic measurements indicate antiferromagnetic intradimer interaction J values of –20.34(5) –25.25(4) cm–1, whereas 3 shows dominant ferromagnetic exchange coupling = 19.11(9) cm–1. DFT calculations performed, theoretically obtained –19.99 (for 1), –24.19 2) 18.81 cm–1 3) corroborate very well experimental results. An attempt has also made to correlate effect Ni···Ni distances bridging Ni–O–Ni angles on constants through calculations. relative energy show diphenoxido-bridged stable at larger angles, consequently antiferromagnetic, bridge, formation angle region energetically profitable.