Synthesis, Characterization and Antibacterial Activity of New Complexes of Some Lanthanide Ions with Benzo 18-Crown-6 and 221-Cryptand

Abstract

Complexes of some lanthanide picrates (Ln 3+ = Pr 3+ , Nd 3+ and Dy 3+ ) with benzo-18-crown-6 and 221-cryptand were synthesized and characterized by elemental analysis, FTIR, and UV-Visible. Spectrophotometric methods, thermal analysis (TGA & DTG), melting point, magnetic susceptibility and molar conductance. Also an in-vitro study on gram positive (Staphylococcus aureus) and gram negative bacteria (Escherichia coli, Salmonella and pseudomonas aeruginosa) was performed and the results were compared to those of the broad spectrum antibiotic Chloramphinicol. The benzo-18-crown-6 complexes have the general formula of (Ln.L.(Pic)2)Pic.nH2O , where; (Ln 3+ = Pr 3+ , Nd 3+ , and Dy 3+ ) , (L = Benzo-18-crown-6) , (Pic = Picrate anion) , (n = 1-2). In these complexes two picrate anions are coordinated to the metal ion through the phenolic oxygen and oxygen of the ortho nitro group, thus, the metal ions in these complexes have a coordination number of (10). The complexes of 221-cryptand have the general formula of (Ln.L.(Pic))Pic2.nH2O where; (Ln 3+ = Pr 3+ , Nd 3+ , and Dy 3+ ), (L = 221-cryptand), (Pic = Picrate anion), (n = 1,2 or 7). In these complexes one picrate anion is coordinated to the metal ion, also through the phenolic oxygen and the oxygen from the ortho nitro group, thus the metal ions in the cryptand complexes have a coordination number of (9).