Heterodinuclear Cu–Gd (3d-4f) complex with di-compartmental Schiff base ligand in biological activity: Synthesis, crystal structure, catecholase activity and DNA & BSA-binding studies

Metal Complexes with Schiff Bases: Data Collection and Recent Studies on Biological Activities

Metal complexes play a crucial role in pharmaceutical sciences owing to their wide and significant activities. Schiff bases (SBs) are multifaceted pharmacophores capable of forming chelating complexes with various metals in different oxidation states. Complexes with SBs are extensively studied for their numerous advantages, including low cost and simple synthetic strategies. They have been reported to possess a variety of biological activities, including antimicrobial, anticancer, antioxidant, antimalarial, analgesic, antiviral, antipyretic, and antidiabetic ones. This review summarizes the most recent studies on the antimicrobial and antiproliferative activities of SBs-metal complexes. Moreover, recent studies regarding mononuclear and binuclear complexes with SBs are described, including antioxidant, antidiabetic, antimalarial, antileishmanial, anti-Alzheimer, and catecholase activities.

Schiff base compounds as artificial metalloenzymes

Much research has been done on traditional homogeneous metal catalysts and enzymatic catalysts, but recently a new class of hybrid catalysts called synthetic (artificial) metalloenzymes has been considered by researchers. Metalloenzymes as hybrid catalysts (host-guest systems) have been shown that combine the properties of a homogeneous and also enzymatic catalyst. The hybrid catalyst will have added value such as enantioselectivity or chemo-selectivity. This review focuses on Schiff base complexes that either act as homogeneous artificial enzymes or contribute to the structure of a host in the preparation of hybrid metalloenzymes. Because this approach can virtually be applied to any bio- or synthetic host or guest coordination complex, the details of hybrid catalysts seem important for advance in catalysis.

New Gd(I)/Cs(III) complexes of benzil‐based thiocarbohydrazone macrocyclic ligand: Chemical synthesis, characterization, and study their biological effectiveness as antibacterial, antioxidant, and antiviral additives for polyurethane surface coating

Germs are transmitted in different ways and remain viable or infectious on metal, glass, wood, fabrics, and plastic surfaces for prolonged periods of time. Thus, sterilizing commonly handled everyday objects and public places with high contamination potential is a major global strategy to combat the spread of pathogenic microorganisms. Consequently, our response is development of durable surface‐active coating embedded with new Gd(I)/Cs(III) complexes that derived from condensation of thiocarbohydrazide and benzil precursors. Chemical structures of these complexes were elucidated by Fourier transform infrared (FTIR), electron impact ionization (EI‐MS), 1H nuclear magnetic resonance (NMR), elemental analysis, and scanning electron microscopy (SEM). Next, the well‐established complexes were physically mixed with wide‐range applicable polyurethane (PU) varnish as potential biocide agents. With laboratory scale, coating material was loaded into stainless steel and wood panels to evaluate the physical and mechanical properties. In comparison with the blank formulation, our additives enhanced the gloss levels of the developed PU from 75 to 80 gloss unit (GU), and the scratch hardness was increased to reach >2 kg. Meanwhile, all the coated films passed the flexibility bend test and showed none flaking in mechanical adhesion test. Consequently, Gd(I) and Cs(III) metal complexes did not show any undesirable side effects on PU coating performance. Concerning biological screening, macrocyclic Gd(I) and Cs(III) complexes as well as the reformulated PU varnish were assayed for their antibacterial, antioxidant, and antiviral activities. Antibacterial activity of the developed PU was slightly increased than the individual treatments of Gd(I)/Cs(III) complexes by 1–2 mm, although the blank PU showed no obvious activity against all the tested bacterial strains. Antiviral overall results indicated that the Gd(I) and Cs(III) complexes demonstrated higher activity than the developed PU samples against ADeno‐7, CV‐B4, and HSV‐1 viruses in all modes of action, and hence these coordinated compounds could be promising virucidal agents with good biocompatibility.

A Stable 3d-4f Heterometallic Cluster with Magneto-Optical Activity

A stable 3d-4f heterometallic cluster, namely, {Dy₄Ni₅L₁₀(NO₃)₄(CO₃)₄(CH₃OH)₂}·CH₃CN (Dy₄Ni₅, HL = 8-hydroxyquinoline), has been solvothermally synthesized and structurally characterized. The compound exhibits an interesting structure in which a tetrahedron based on 4f ions interpenetrates with a square pyramid based on 3d ions. Besides, a unique intermolecular interaction was found in Dy₄Ni₅, giving rise to its high stability not only when it is in the solid state but also when it dissolves in organic solvents. In addition, the magnetic behavior of solid Dy₄Ni₅ and the magneto-optical activity of the Dy₄Ni₅ solution were also studied.