Construction of Pyrazine-Appended 1D and 3D Cobalt(II) Succinate Coordination Polymers: Influence of Solvent on Architectures and Applications in Gas Adsorption and NAC Detection

An underexplored reaction of pyrazine (rigid and linear) and succinic acid (flexible) with Co(NO3)(2)center dot 6H(2)O afforded four new coordination polymers (CPs): [Co(H2O)(pyz)(suc)] (1), [Co(H2O)(2)(pyz)(suc)] (2), [Co(H2O)(4)(pyz)](suc) (3) and [Co-2(H2O)(2)(pyz)(suc)(2)] (4), as well as [Co(HCO2)(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 crystallogra-phy. 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 XM-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 (0) of -46.24 K, suggesting weak antiferromagnetic (AF) exchange interactions. CO2 and N-2 adsorption studies of 1-5 featured type III isotherms. 1 was found to show remarkably higher quenching efficiencies for nitrophenols (ti = 98% for o-NP) over other NACs. The Stern-Volmer plot exhibited deviation in linearity with Ksv 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.