Synthesis, spectral characterization and in vitro microbiological evaluation of novel glyoxal, biacetyl and benzil bis-hydrazone macrocyclic Schiff bases and their Co(II), Ni(II) and Cu(II) complexes

Abstract

A series of binuclear Co(II), Ni(II) and Cu(II) complexes were synthesized by the template condensation of glyoxal, biacetyl or benzil bis-hydrazide, 2,6-diformyl-4-methylphenol and Co(II), Ni(II) or Cu(II) chloride in a 2:2:2 M ratio in ethanol. These 22-membered macrocyclic complexes were characterized by elemental analyses, magnetic, molar conductance, spectral, thermal and fluorescence studies. Elemental analyses suggest the complexes have a 2:1 stoichiometry of the type [M 2 LX 2 ]ÁnH 2 O and [Ni 2 LX 2 2H 2 O]ÁnH 2 O(where M = Co(II) and Cu(II); L = H 2 L 1 , H 2 L 2 and H 2 L 3 ; X = Cl; n = 2). From the spectroscopic and magnetic studies, it has been concluded that the Co(II) and Cu(II) complexes display a five coordinated square pyramidal geometry and the Ni(II) complexes have a six coordinated octahedral geometry. The Schiff bases and their metal complexes have also been screened for their antibacterial and antifungal activities by the MIC method.

Bio-relevant complexes of novel N2O2 type heterocyclic ligand: Synthesis, structural elucidation, biological evaluation and docking studies

“…In the FT-IR spectrum of ligand (H 2 L) ( Fig.S1a. ), the band acquired at ~1627 cm -1 is ascribed to the characteristic of imine functional groups, which supports the formation of ligand (H 2 L) from benzil and methionine [20]. The bands found in the region of 1400-1600 cm -1 are due to the aromatic C=C bonds.…”

Synthesis and multi‐spectroscopic study on DNA‐binding, cleavage and biological properties of M(II) complexes based on N2O2 donor Schiff base ligand

“…Infrared spectra of the synthesized ligand and its metal complexes were represented in Figure S1 and the main IR vibrational bands are compared and listed in Table S4. In the FTIR spectrum of ligand (L) (Figure S1), the absence of the carbonyl (C = O) stretch and the appearance of the characteristic azomethine ν(−C = N) at 1682 cm −1 confirmed the formation of the Schiff base from 1,3‐indandione and methionine . Upon complexation with metal ions this band is shifted to lower frequencies (1605–1608 cm −1 ) indicating the participation of azomethine nitrogen in coordination with the metal ions .…”

Characterization and biological activity studies on some transition metal complexes of thiosemicarbazide derived from 2-picolinic acid hydrazide

“…Thiosemicarbazones have been extensively studied because they have a wide range of actual or potential medical applications [1][2][3] which include notably antiparasital [3], antibacterial [4] antitumor activities [5], antiviral [6], fungicidal [7] and antineoplastic [8]. Thiosemicarbazones derived from 2picolinic acid hydrazide and its derivatives are classes of versatile tridentate NNS donors capable of stabilizing both higher and lower oxidation states of transition metal ions [9,10].…”