Preparation Characterization and Antibacterial Studies of Chelates of Schiff Base Derived from4‐Aminoantipyrine, Furfural and o‐phenylenediamine

Abstract

A new series of transition metal complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) were synthesized from the Schiff base ligand derived from 4-aminoantipyrine, furfural ando-phenylenediamine. The structural features were derived from their elemental analyses, infrared, UV-visible spectroscopy, NMR spectroscopy, thermal gravimetric analyses, ESR spectral analyses and conductivity measurements. The data of the complexes suggested square planar geometry for the metals with primary valency two. Antimicrobial screening tests were performed against bacteria. The comparative study of the MIC values of the Schiff base and its metal complexes indicate that the metal complexes exhibit greater antibacterial activity than the free ligand.

Synthesis, spectral characterization, thermal studies and biological activity of (Z)‐5‐((1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)diazenyl)‐6‐hydroxy‐2‐mercaptopyrimidin‐4(3H)‐one and its metal complexes

“…The ESR parameters and the d–d transition energies are used for calculation of the bonding coefficients α 2 , β 1 2 and γ 2 (Table and Figure ) which are used to measure in‐plane (σ) bonding, in‐plane and out‐of‐plane (π) bonding, respectively. These bonding parameters were calculated according to the following equations: where λ o is the spin–orbital coupling of free Cu(II) ion and equals −828 cm −1 , and Δ 1 and Δ 2 are the electronic transitions defined as 2 B 1g → 2 E g and 2 B 1g → 2 B 2g , respectively. According to Hathaway et al ., the observed k || < k ⊥ signifies a higher contribution of in‐plane π‐bonding contribution than out‐of‐plane π‐bonding .…”

Synthesis, Characterization and Biological Activity of Schiff Bases Chelates with Mn(II),Co(II),Ni (II),Cu(II) and Hg(II)

“…[Mn(L 2 )]complex, exhibits four peaks, the first and second high peaks at (275nm) and (331nm) are due to (L.F) and (C.T)transition. The fourth-week peak at (396nm) and (957 nm) can be assigned to the 6 A 1 g (F) → 4 T 2 g (G) ( 3 ) and 6 A 1 g (F) → 4 T 2 g (G) ( 2 )transitions. Magnetic moment µ eff = 4.72 B.M at room temperature, this low data of the magnetic moments suggest high spin [20] a coordination number of 6 for the central manganese (II) ion and attaining [an octahedral geometry].…”

“…There is no ligand field stabilisation activtiy Hg (II) ions because of its completed (d 10 ) shell. This metal ion is diamagnetic and does not possess any d-d transition [21] Antibacterial Activities: Tetradent and hexadentate Schiff base ligands (L 1 ,L 2 ) and the Mn(II),Cu(II), Ni(II),Co(II), and Hg(II) complexes showed biological activities against the four types of bacterial Figure (6&7), Table (6). On the comparing the antimicrobial activities of the Schiff base ligands and their complexes with those of normal bacteria, it was shown that the complexes had reasonable activity as compared to the normal but all the metal complexes were larger active than their free ligands.…”

“…Now there are new studies attracting the attention of biochemists around new types of Schiff bases derivative from 4-aminoantipyrineand its complexes, generally because of their use in the assortment of applications in analytical biological, pharmacological, clinical areas and especially chemotherapeutic applications [1][2][3]. The precedent literatureex plains increasing activity for organic compounds used drugs when they are treated as metal complexes [4][5][6]. In the 1980s some investigations show that the interaction of little molecules with DNA are very necessary for the styling of new kinds of molecules such as pharmaceutical [7] and their transition metal complexes which have chemical nuclease activity; it is studying the technicality of DNA with transition metal complexes and the interaction model [8].…”

Synthesis of innovative biochemical active mixed ligand metal(II) complexes with thiazole containing Schiff base: In vitro antimicrobial profile

“…The development of chemical reagent capable of cleaving DNA has many considerable effort, designed in transition metal complexes as chemical nucleases based on the coordination environment, structural diversity and versatile redox properties of the metal centre through the appropriate choice of ligands . Primarily, 2‐aminobenzothiazole, β‐diketone and their derivatives are well known for their variety of clinical applications . The chemistry of transition metal complexes with multidentate ligands has been studied for their applications in biological, analytical and pharmacological areas, which intensified the attention of researchers because these metal ions can exhibit variable oxidation states and can form metal complexes with Schiff base ligands.…”