Co(II), Ni(II), Cu(II) and Zn(II) complexes of aminothiazole‐derived Schiff base ligands: Synthesis, characterization, antibacterial and cytotoxicity evaluation, bovine serum albumin binding and density functional theory studies

Abstract

Transition metal complexes of type M(L)2(H2O)x were synthesized, where L is deprotonated Schiff base 2,4‐dihalo‐6‐(substituted thiazol‐2‐ylimino)methylphenol derived from the condensation of aminothiazole or its derivatives with 2‐hydroxy‐3‐halobenzaldehyde and M = Co2+, Ni2+, Cu2+ and Zn2+ (x = 0 for Cu2+ and Zn2+; x = 2 for Co2+ and Ni2+). The synthesized Schiff bases and their metal complexes were thoroughly characterized using infrared, 1H NMR, electronic and electron paramagnetic resonance spectroscopies, elemental analysis, molar conductance and magnetic susceptibility measurements, thermogravimetric analysis and scanning electron microscopy. The results reveal that the bidentate ligands form complexes having octahedral geometry around Co2+ and Ni2+ metal ions while the geometry around Cu2+ and Zn2+ metal ions is four‐coordinated. The geometries of newly synthesized Schiff bases and their metal complexes were fully optimized in Gaussian 09 using 6–31 + g(d,p) basis set. Fluorescence quenching data reveal that Zn(II) and Cu(II) complexes bind more strongly to bovine serum albumin in comparison to Co(II) and Ni(II) complexes. The ligands and their complexes were evaluated for in vitro antibacterial activity against Escherichia coli ATCC 25922 (Gram negative) and Staphylococcus aureus ATCC 29213 (Gram positive) and cytotoxicity against lever hepatocellular cell line HepG2.

Metal incorporated aminothiazole-derived compounds: synthesis, density function theory analysis,in vitroantibacterial and antioxidant evaluation

“…Complex (9) showed the highest activity of 27 mm against two bacterial strains, Escherichia coli and Salmonella typhimurium, and moderate activity of 25 and 20 mm for Bacillus subtilis and Staphylococcus aureus, individually. Similarly, complex (14) was also found to be more active with an inhibition zone of 28, 25, 25 and 20 mm for Staphylococcus aureus, Escherichia coli, Salmonella typhimurium and Bacillus subtilis, respectively. Complexes (7), ( 10), ( 13) and (17) exhibited moderate activity and inhibited 25 mm zone area of Salmonella typhimurium.…”

“…Thiazole consists of five-membered heterocyclic ring having nitrogen and sulfur at first and third positions in the ring system [13]. The biological significance of the thiazole ring is well recognized as well as reported in the literature, such as penicillin is the earliest known antibiotic drug having a tetrahydrothiazole moiety in its structure [14]. Likewise, vitamin B1 and the coenzyme cocarboxylase also contain a thiazole ring.…”

Advances in chromone-based copper(ii) Schiff base complexes: synthesis, characterization, and versatile applications in pharmacology and biomimetic catalysis

“…[70][71][72] This is due to their specic structure, and large binding affinity with metal ions. 73,74 Herein, we have discussed chromone Schiff base sensors which bind to Cu 2+ ions making exclusive coloured copper complexes and thus can be used as colorimetric sensors.…”

An Overview on Synthetic 2-Aminothiazole-Based Compounds Associated with Four Biological Activities

“…There are many substituted thiazole-containing heterocycles covering a wide range of therapeutic targets including antimicrobial, anticancer, anti-inflammatory and anti-HIV. Aminothiazole scaffolds are important structural units in medicinal chemistry as they have shown antitumor [ 1 , 2 , 3 ], antiviral [ 4 , 5 , 6 ], antibacterial [ 7 , 8 , 9 ], anti-prion [ 10 ], psychotropic [ 11 ], anti-allergic [ 12 ], anti-hypertensive [ 13 ], anti-inflammatory [ 14 , 15 ], antifungal [ 16 ], antitubercular [ 17 , 18 ], anti-HIV [ 19 ], pesticidal [ 20 ], antiprotozoal [ 21 ], antipyretic [ 22 ], antioxidative [ 23 ] and analgesic activities [ 24 ]. Aminothiazole compounds act as ligands of estrogen receptors [ 25 ] and afford a new group of adenosine receptor antagonists [ 26 ].…”