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

• Published in: Applied organometallic chemistry 2017-12, Vol.31 (12), p.n/a
• Main Authors: Abdel Aziz, Ayman A., Seda, Sabry H.
• Format: Article
• Language: English
• Subjects: Absorption; biochemical assessment; characterization; Chemistry; Coordination compounds; Copper; Deoxyribonucleic acid; DNA; Imines; Infrared radiation; Ligands; Magnetic permeability; Nickel; NMR; NSSN thiophene Schiff base complexes; Nuclear magnetic resonance; synthesis; Zinc
• ISSN: 0268-2605; 1099-0739
• DOI: 10.1002/aoc.3879

The tetradentate Schiff base ligand (SB), N,N′‐bis‐(2‐mercaptophenylimine)‐2,5‐thiophenedicarboxaldehyde was prepared via condensation of 2,5‐thiophene‐dicarboxaldehyde 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, 1H NMR, 13C 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. Four first row transition metal complexes were synthesized form novel tetradentate Schiff base with N2S2 coordination sites namely, N,N′‐bis‐(2‐mercaptophenylimine)‐2,5‐thiophenedicarboxaldehyde under aerobic and thermal conditions The novel compounds were fully characterized by elemental analysis, FT‐IR, 1H NMR, 13C NMR, UV–Vis, ESR ESI‐mass, conductivity, and magnetic susceptibility measurements. Biological activity assessment of novel compounds was performed via studying antimicrobial activity, antioxidant scavenging and DNA interactions.