Synthesis of Azo Schiff Base Ligands and Their Ni(II), Cu(II) and Zn(II) Metal Complexes as Highly‐Active Antibacterial Agents

Abstract

In the present work, a simple synthetic route was reported for the preparation of azo oxime based Schiff base ligands and their Ni(II), Cu(II) and Zn(II) complexes. 2-hydroxy-3-methoxy-5-(phenyldiazenyl)benzaldehyde oxime (HL 1 ) ligand was synthesized by condensing 2-hydroxy-3-methoxy-5-(phenyldiazenyl) benzaldehyde and hydroxyl amine hydrochloride in the molar ratio 1:1. Nitro and chloro substituted ligands, 2-hydroxy-3methoxy-5-((4-nitro-phenylazo)benzaldehyde oxime (HL 2 ) and 2-hydroxy-3-methoxy-5-(2-chloro-phenylazo)benzaldehyde oxime (HL 3 ) respectively, were also synthesized by the same method. The synthesized ligands were used to prepare metal complexes of Ni(II), Cu(II) and Zn(II) which were characterized by various analysis techniques. Ligands and their metal complexes were tested for their in vitro antibacterial and antioxidant activities. Ligands shows good antibacterial activity and it increases remarkebly after metal complexetion with MIC (Minimum inhibitory concentration) ranging from 3.90 μM/mL to 125 μM/mL for Zn(II) metal complexes over standard broad spectrum drug chloramphenicol having MIC 386 μM/mL against gram positive as well as gram negative bacteria. Synthesized ligands showing good antioxidant property which is comparable to that of natural antioxidant Ascorbic acid.[a] M. S. Kasare, Dr.

Recent Progress in Metal‐Incorporated Acyclic Schiff‐Base Derivatives: Biological Aspects

“…Using the DPPH⋅ scavenging method, Pawar and co‐workers also studied the antioxidant activity of Schiff‐base ligands L17 and L18 (Figure 12). The obtained free radical scavenging activity (IC 50 value of 92.20 μM mL −1 for L17 and that of 130.73 μM mL −1 for L18 ) was comparable to that of the standard antioxidant ascorbic acid (IC 50 value of 74.06 μM mL −1 ) [77] . Sithique and co‐workers studied the total antioxidant activities of chitosan Schiff‐base ligands L20 – L21 and their Zn II complexes 33–34 [82] .…”

Synthesis, Spectroscopic, Biological Activity, Molecular Docking and Density Functional Theoretical Investigations of Novel Tellurium(IV) Schiff Base Complexes

“…On chelation, polarity of the tellurium metal reduced due to overlapping with ligand orbitals and sharing of charge with donor atoms which increases the lipophilic character of the complexes and blocks the synthesis of protein which stops the further growth of micro-organisms. Literature survey shows the Schiff base ligand and its metal complexes possess biological activities like antibacterial, [6][7][8] antifungal, [9,10] anti-inflammatory, [11] antioxidant, [12,13] analgesics, [7] antitumor [14][15][16] and antiviral [17,18] activities.…”

Synthesis and Characterization of Some New Azo-Schiff Bases as Energy Rich Candidate Compounds Derived from 1, 5-Diaminoanthraquinone by Fusion Method

“…Their multi sites of coordination were precious opportunity for those who carry out researches. Relating to coordination chemistry [7][8][9][10][11][12][13][14][15]. For researchers interesting in the field of biological activities, it was a chance to test the double effect of their both groups [16][17][18][19][20].…”

“…heated for(15)(16)(17)(18)(19)(20) minutes. Heating was stopped when the color and statue of the mixture changed.…”

“…3204) cm -1 in addition to the shift in the location of intra hydrogen bonded carbonyl group from (1609 cm -1 ) of the starting material to (1655-1659) cm -1 are strong evidences for the development of the product. The appearance of new sharp bands at (1612-1620) cm -1 referring to (CH=N group) indicates the formation of Schiff bases[7][8][9][10][11][12][13][14][15][16][17][18]. Moderate bands at (1580-1595) cm -1 referring to the stretching absorption of aromatic (C=C) bond and weak bands (1017-1060) cm -1 due to (N=N) group are another evidence for the formation of the desired product.…”