The Effects of Coordinated Molecules of Two Gly-Schiff Base Copper Complexes on Their Oxygen Reduction Reaction Performance

Abstract

In this study, two simple Schiff base copper complexes [Cu(H 2 O) 2 (HL)]•2H 2 O (Complex 1) (H 3 L = 2-OH-4-(OH)-C 6 H 2 CH=NCH 2 CO 2 H) and [Cu(py) 2 (HL)] (Complex 2) (Py = pyridine) were initially achieved and authenticated by single-crystal X-ray structure analyses (SXRD), powder X-ray diffraction analyses (PXRD), FT-IR spectroscopy, and elemental analyses. The SXRD reveals that the Cu 2+ center in Complex 1 exhibited a distorted square pyramidal geometry, which is constructed based on phenolate oxygen, water molecules, carboxylate oxygen, and imine nitrogen from a deprotonated H 3 L ligand in an NO 4 fashion. The Cu 2+ atom in Complex 2 had distorted square pyramidal geometry, and was coordinated with two pyridine molecules and one Gly-Schiff base ligand, exhibiting an N 3 O 2 binding set. Additionally, the free water molecules in Complex 1 linked independent copper complexes by intermolecular hydrogen bond to form a 2D framework. However, the one-dimensional chain supramolecular structure of Complex 2 was formed by the intermolecular O-H. .. O hydrogen bonds. The oxygen reduction performance of the two complexes was analyzed by cyclic voltammetry (CV) and the rotating disk electrode (RDE) method. Both complexes could catalyze the conversion of oxygen to water through a predominant four-electron pathway, and the Cu-N x O y moieties might be the functional moieties for the catalytic activity. The catalytic pathways and underlying mechanisms are also discussed in detail, from which the structure-activity relationship of the complexes was obtained.

Supramolecular Iron Complex Formed Between Nitrogen Riched Phenanthroline Derivative and Iron With Improved Oxygen Reduction Activity in Alkaline Electrolyte

“…The resulting solid product was dried in the vacuum dryer to obtain our target product, which was named as Fe-PIPhen/C. The synthesis route is exhibited in Scheme 1 (Ma et al, 2018).…”

Morphology based catalytic oxidation of phenylpropyne into 1,2-diketones, aldehyde and acid using Cu(II) complex

“…The fourth coordination is occupied by exogenous anion (Br -) ion, forming distorted square plane. The bond length of copper with exogenous anion (Br -) is elongated than the remaining three bonds with NNO contributing to the distortion in the square planer geometry [45,46] . Table 1 shows the value of lattice constants obtained after the Le-Bail fitting.…”