Structures, magnetism, and oxygen evolution reaction (OER) of azidoisophthalate bridging Cu(II) and Co(II) coordination polymers

Abstract

Two newly derived coordination polymers of Cu(II) and Co(II), namely {[Cu(μ‐5‐AzIA)(Py)2]⋅[Cu(5‐AzIA)(Py)2(H2O)]}n (CP1) and {[Co(μ‐5‐AzIA)2(Py)4]⋅[Co(5‐AzIA)(Py)2]}n (CP2) (5‐AzIA2− = 5‐azidoisophthalate; Py = pyridine) are synthesized and structurally characterized by single‐crystal X‐ray diffraction (SXRD), powder X‐ray diffraction (PXRD), and Fourier transform infrared data. As evident from thermogravimetric data, CP1 loses coordinated water at 110°C and the final residue reaches at 530°C as CuO; CP2 is stable up to 150°C, and the final residue reaches at 415°C as Co2O3. 5‐AzIA2− serves as both chelating and monodentate carboxylate bridging ligand to the adjacent metal centers (Cu(II) in CP1 and Co(II) in CP2) to construct the CPs. The CPs form eight‐member carboxylato bridging, [M2(RCOO)2], and coordinate with Py rings and assemblage through π‐‐‐π interaction. The magnetic measurements of the CPs show antiferromagnetic super‐exchange properties. Interestingly, CP2 shows field‐induced magnetic ordering at a higher magnetic field at a temperature  ̴ 2 K owing to the π•••π stacking between the flagging pyridine moieties. Oxygen evolution reaction (OER) shows excellent catalytic effectiveness of CP2 than CP1 with reference to standard RuO2 catalyst. The comparative catalytic activity of CP1 and CP2 was thoroughly investigated and well supported by Tafel slope, charge‐transfer resistance (Rct), and electrochemically active surface area calculation.