Abstract
An underexplored reaction of pyrazine (rigid and linear) and succinic acid (flexible) with Co(NO(3))(2)·6H(2)O afforded four new coordination polymers (CPs): [Co(H(2)O)(pyz)(suc)] (1), [Co(H(2)O)(2)(pyz)(suc)] (2), [Co(H(2)O)(4)(pyz)](suc) (3) and [Co(2)(H(2)O)(2)(pyz)(suc)(2)] (4), as well as [Co(HCO(2))(2)(pyz)] (5) being lately reported along with well-known 6 and 7. The CPs were obtained as stable crystalline materials and characterized by conventional solid-state techniques, including X-ray crystallography. Hydrothermally produced compounds 1 and 2 were both 3D CPs. While 3 and 4 obtained under ambient/solvothermal conditions in DMSO generated 1D and 3D structures, 5 isolated from DMF under solvothermal conditions had a 3D structure. The topologies of the coordination polymers 1-7 were described by underlying nets 3D 5-c fet, 3D 4-c cds, 1D 2-c 2C1, 3D 5-c bnn, 3D 6-c rob, 1D 2-c 2C1, and 3D 6-c pcu, respectively. The plot of χ(M) (-1) versus T was essentially linear in the entire temperature range following the Curie-Weiss law with a Curie constant (C) of 2.525 and a negative Weiss constant (ϕ) of -46.24 K, suggesting weak antiferromagnetic (AF) exchange interactions. CO(2) and N(2) adsorption studies of 1-5 featured type III isotherms. 1 was found to show remarkably higher quenching efficiencies for nitrophenols (η = 98% for o-NP) over other NACs. The Stern-Volmer plot exhibited deviation in linearity with K (sv) values about 200 times greater than that for the simplest nitroaromatic compound (NB), signifying its exclusive quenching ability toward 1. The LOD for p-NP addition to 1 was found to be 0.995 ppm.