Pd-Immobilized Schiff Base Double-Layer Macrocycle: Synthesis, Structures, Peroxidase Mimic Activity, and Antibacterial Performance

Abstract

Di-, tri-, and tetra-aldehydes have been employed to access new [2 + 2] [2 + 3] and [2 + 4] double-layer Schiff base macrocycles. The [2 + 3] compound has been used for the immobilization of Pd and the resulting composite has been employed as a peroxidase-like mimetic using 3,3′,5,5′-tetramethylbenzidine (TMB) as the substrate; the optimum conditions together with the catalytic kinetics of the enzyme-like activity is discussed. Based on the peroxidase-like catalytic activity, the Pd@ Schiff base composite was found to exhibit excellent bactericidal activity against both Escherichia coli (Gram-negative bacterium) and Staphylococcus aureus (Gram-positive bacterium) in the presence of relatively low concentrations of H 2 O 2 . Furthermore, cytotoxicity measurements illustrate the biosafety of the Pd composite. The above-mentioned findings have the potential to guide the innovation of new Pd-based composites as enzyme mimetics and antibacterial materials.

Experimental and Theoretical Studies of the Optical Properties of the Schiff Bases and Their Materials Obtained from o-Phenylenediamine

“…The multi-donor macrocyclic Schiff bases (e.g., S, N, O) can form compounds of various structures, which are crucial in coordination chemistry, as they can influence the structural, magnetic, or optical properties of the obtained complexes [ 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. The isolation of mono-, bi-, and polynuclear complexes is possible [ 18 , 19 ].…”

Pd nanoparticles decorated ultrathin 2D metal–organic framework nanosheets with enhanced peroxidase–mimic activity and colorimetric assay of glucose

“…So far, important progresses have been achieved in developing PdNPs-based nanozymes, such as Pd@Au, GSH-Pd nanoparticles, Pd@ZIF-8. [27][28][29][30][31][32][33][34][35][36] However, to the best of our knowledge, there have been few literature about PdNPs doped 2D MOF hybrids.…”

Exploring the Antibacterial and Biosensing Applications of Peroxidase-Mimetic Ni0.1Cu0.9S Nanoflower

“…A natural enzyme is a kind of biocatalyst that can catalytically mediate various physiological processes in living organisms [ 1 , 2 ]. The reactions involving natural enzymes are highly efficient and specific [ 3 ].…”

“…As opposed to the drawbacks of natural enzymes, artificial enzymes (also known as nanoenzymes) with the merits of robust stability, simple preparation, high reliability, low cost and tunable catalytic properties can be used in harsh reaction situations [ 5 , 6 ]. Consequently, nanoenzymes, especially those that could promote the production of reactive oxygen species (ROS), can be wildly applied to disease treatment [ 7 , 8 ], biological detection [ 9 , 10 ], bacteriostasis [ 1 , 11 , 12 , 13 ] and other fields [ 14 ].…”