Asian Journal of Research in Chemistry

Saritha Aduri ¹, Venkata Ramana Reddy ², B. Sireesha ¹

Affiliations
1 Department of Chemistry, Nizam College, OU, Hyderabad-500 001, IN
2 Department of Chemistry, Jawaharlal Nehru Technological University Hyderabad, Hyderabad-500 085, IN

Abstract

The formation and stability of Pyridoxal semicarbazone (PLSC) and Pyridoxal thiosemicarbazone (PLTSC) Schiff base ligand (L) complexes of Co(II), Ni(II), Cu(II) and Zn(II) have been investigated by Irving-Rossotti pH-metric titration technique, at 30 ± 1°C and an ionic strength of 0.1M KNO₃ in 70% v/v DMF-H₂O medium. The acid dissociation constants (pK_a) of the ligands and the stability constants of the metal complexes formed in solution were determined. The results indicate the formation of 1:1(ML) and 1:2(ML₂) complexes in solution. The order of stability of the metal complexes with respect to the metal ions follows the Irwing - william's natural order, Co(II), Ni(II), Cu(II) > Zn(II).

Keywords

Schiff Base, Transition Metals, pH Metry, Stability Constants.

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R. Kavitha ¹, Venkata Ramana Reddy ², B. Sireesha ¹

Affiliations
1 Department of Chemistry, Nizam College, OU, Basheerbagh, Hyderabad-500001, Telangana, IN
2 Department of Chemistry, Jawaharlal Nehru Technological University Hyderabad, Kukatpally, Hyderabad-500085, Telangana, IN

Abstract

The Co(II) metal (M) complex of 2,4-dichloro-N-((3-hydroxy-5-(hydroxymethyl)-2-methylpyridin-4-yl)methylene)benzohydrazide (L) was synthesized and characterized by elemental analysis, molar conductance, magnetic moment measurements, LC-MS, IR, TGA and UV spectral studies. Irving-Rossetti titration method was employed to determine the acid dissociation constant of ligand and the stability constant of Co(II) complex in 70% (v/v) DMF-water medium at 0.1 M KNO₃ ionic strength and 303K temperature. The spectroanalytical data indicate the composition of the complexes to be 1:2 (ML₂) with octahedral geometry. The ligand and the complex were screened for their antibacterial activity against Gram positive and Gram negative bacteria using agar well diffusion method.

Keywords

Pyridoxal, Schiff Base, Complex, Stability Constant, Antibacterial Activity.

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