One-Dimensional [Ni(O2CR)2(N[BOND]N)x] Polymers: Structural, Magnetic, and Density Functional Theory Studies



Five nickel complexes, [Ni2(3,4,5-tmb)4(4,4′-bpy)] (1), [Ni2(2-ntc)4(4,4′-bpy)] (2), [Ni(9-atc)2(4,4′-bpy)] (3), [Ni(3,4,5-tmb)2(t-bpee)] (4), and [Ni2(2-ntc)4(t-bpee)2] (5) (3,4,5-tmb=3,4,5-trimethoxybenzoate; 2-ntc=2-naphthalenecarboxylate; 9-atc=9-anthracenecarboxylate; 4,4′-bpy=4,4′-bipyridine; t-bpee=trans-1,2-bis(4-pyridyl)ethylene), are prepared. They are characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and single-crystal and powder X-ray diffraction. 1 and 2 form linear chains of paddlewheel units joined by 4,4′-bpy ligands; 3 and 4 display zigzag chains formed by cis-bis(chelate) Ni(O2CR)2 units joined by 4,4′-bpy and t-bpee, respectively; and the structure of 5 consists of double chains. The magnetic behavior of the compounds is also studied, and DFT calculations using the broken-symmetry approximation are performed to gain a better understanding of the strong antiferromagnetism found in 1.