Spectral Investigation andIn VitroAntibacterial Evaluation of Ni^IIand Cu^IIComplexes of Schiff Base Derived from Amoxicillin andα-Formylthiophene (αft)

Abstract

Two new metal complexes of general formula M(Haαft)2[M =NiIIandCuII] of asymmetrical Schiff base ligand (HL = Haαft) derived from amoxicillin andα-formylthiophene have been prepared and characterized by various physicochemical and spectral techniques. Molar conductance measurement indicates nonelectrolytic nature of the metal complexes. FT-IR spectral study reveals the ligation of metal ions at two different nitrogen [NN] donor sites of Haαft. FT-IR and electronic absorption spectral evidences suggest distorted tetrahedral and square planar geometry forCuIIandNiIIcomplexes, respectively. The structure optimization by molecular mechanics (MM) force field calculation through ArgusLab 4.0.1 version software also supports the concerned geometry of the complexes. The cell dimensions as suggested by XRPD study,a(6.753 Å),b(13.904 Å),c(20.122 Å),α(142.76°),β(106.580°), andγ(72.4343°) forCuIIanda(24.2547 Å),b(6.6371 Å),c(5.5047 Å) (α=β=γ= 90°) forNiIIcomplexes, are in good agreement with their triclinic and orthorhombic crystal systems. Particle size calculation by Scherrer’s formula indicates nanocrystalline nature of the complexes. The antibacterial sensitivity study suggests promising activities of Haαft (Ligand) and M(Haαft)2complexes against four clinical pathogenic bacteria, namely,E. coli,P. vulgaris,P. aeruginosa, andS. aureus, though being less active than the standard drug amikacin.

Microwave Preparation, Spectral Studies and Antimicrobial Activities Evaluation of Mn(II),Ni(II), Hg(II),Co(II) and Cu(II) Complexes with Schiff Base Ligand

“…The phenolic C-O stretching vibration that showed at (1211) cm -1 in the ligand, this band was shifted towards higher frequencies about (22-16) cm -1 in the complexes, Figure (2). This suggests deprotonation of the phenolic OH group after its coordination with the metal ion [9]. This shift confirms the participation of oxygen in the C-O-M bond.…”

“…The studies about behavior ligands in the chelation with transition metal ions by using the microwave as assisted were considered as one of the important properties in green chemistry [9]. The application of microwave-supported preparation continues to develop in organometallic [10], coordination [11] and organic chemistry pace [12].…”

Antibacterial activity of transition metal complexes containing a tridentate NNO phenoxymethylpenicillin‐based Schiff base. An anti‐MRSA iron (II) complex

“…[32] The NMR spectrum of Schiff base 3, also revealed multiplets at 6.80-7.62 ppm, corresponding to aromatic protons which were displaced in the upper field direction around 6.50-7.58 ppm suggesting coordination through azomethine-N and amino-N atoms. [9,[13][14][15] Because of the low solubility of the diamagnetic complex 8 in most organic solvents it was not possible to obtain an acceptable 13 C NMR spectrum.…”

“…Continuing with the studies on novel antibiotic-based Schiff base metal complexes [13][14][15][16][17][18][19] and in order to establish whether complexation affects the bactericidal properties of 1, this paper was focused on the synthesis and characterization of transition metal-Schiff base complexes containing a PMP-derived Schiff base 3, obtained from the reaction of free PMP 1 with 1,2-diaminobenzene 2. Molecular structure of 1 is shown in Figure 1.…”

Synthesis and physicochemical characteristics of Nickel (II), Copper (II), Zinc (II), Cadmium (II) and Tin (II) complexes of schiff base with 1, 2, 4-triazole

“…A mixture of 4-Amino-5-pyridin-4-yl-4H-[1,2,4] triazole-3-thiol (1g, 0.005mol), benzaldehyde (0.005mol) and 4-5 drops of glacial acetic acid in ethanol medium was refluxed for 3 hrs [19] . The resulting solution was cooled to room temperature and the precipitated solid, was filtered, washed with cold ethanol and recrystallized from hot ethanol, Scheme 1.…”