Synthesis, structural features and biochemical activity assessment of N,N′‐bis‐(2‐mercaptophenylimine)‐2,5‐thiophenedicarboxaldehyde Schiff base and its Co(II), Ni(II), Cu(II) and Zn(II) complexes

Abstract

The tetradentate Schiff base ligand (SB), N,N′-bis-(2-mercaptophenylimine)-2,5thiophenedicarboxaldehyde was prepared via condensation of 2,5-thiophenedicarboxaldehyde with 2-aminothiophenol in a 1:2 molar ratio by conventional method. Additionally, its Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized and fully characterized by elemental analysis, FT-IR, 1 H NMR, 13 C NMR, UV-Vis, ESR, ESI-mass, conductivity and magnetic susceptibility measurements. Spectral studies suggested that, the Schiff base coordinate metal ions through the azomethine N-and deprotonated thiol S-atoms. Based on UV-Vis absorption and magnetic susceptibility data, tetrahedral geometry was assigned for both Co(II) and Zn(II) complexes, whereas on the other hand, square planar geometry for both Ni(II) and Cu(II) complexes. The Schiff base and its metal complexes were screened for their in vitro antimicrobial activity by minimum inhibitory concentration (MIC) method. Free radical scavenging activity of the novel compounds was determined by elimination of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. In addition, the interactions of the free ligand and its complexes with calf thymus DNA (CT-DNA) were explored using absorption, emission and viscosity measurements techniques.

Design of Promising Heptacoordinated Organotin (IV) Complexes-PEDOT: PSS-Based Composite for New-Generation Optoelectronic Devices Applications

“…The synthesis feasibility of Schiff base ligands makes them useful in materials chemistry. The polyfunctional groups can easily be added giving rise to a unique structural metallic array with an abundance of applications [ 29 , 30 , 31 , 32 , 33 , 34 ]. Among them, the organotin complexes, that have received much attention in view of their significant structural possibilities and a wide range of biological activities, such as antiviral, anticancer, antibacterial, antifungal, and anti-inflammatory; have been associated to the organic fragment nature bonded to the tin atom [ 35 , 36 ].…”

Thiophene‐containing compounds with antimicrobial activity

“…The tetradentate ligand that was employed in the synthesis of complexes 239 (X = S) (Figure 28) is also a bis‐Schiff base and it was obtained from thiophene‐2,5‐dicarboxaldehyde and 2‐aminothiophenol. [ 216 ] The antimicrobial activity of the ligand was poor, but chelation led to an overall marked enhancement in activity against all of the microbes included in the study (four bacteria and three fungi). Generally, the copper complex was the most active, followed by the nickel and cobalt complexes, while the antimicrobial activity of the zinc complex was weak.…”

Antibacterial Activity of Carboxymethyl Chitosan Dialdehyde Starch Schiff Base and its Metal Complex

“…[16,17] Silver was a widely used precious metal according to its antibacterial activities against planktonic and sessile bacteria. [18] Azo Schiff base ligand 2-hydroxy-3-methoxy-5-(tolyldiazenyl) benzalde-hyde oxime, [19] synthesized by 2-hydroxy-3-methoxy-5-(p-tolyldiazenyl) benzaldehyde oxime and 2-hydroxy-3-methoxy-5-(tolyldiazenyl) benzaldehyde, and its metal complexes [20] showed best bacteriostatic effect on gram-positive and gram-negative. Thiosemicarbazide, 3-methoxy-2-hydroxybenzaldehyde, [21] and their metal complexes [20] also showed good considerable antifungal activity on Aspergillus flavus and Canceromyces albicans.…”