Complexes of some lanthanide picrates (Ln 3+ = Pr 3+, Nd 3+ and Dy 3+ ) with 15-crown-5 and 18-crown-6 were synthesized and characterized by elemental analysis, ICP-AES, FTIR, 1 H-NMR, 13C-NMR and UV-Visible spectrophotometric methods, thermal analysis (TGA & DTG), magnetic susceptibility , molar conductance and melting points. Also an in-vitro study on pathogenic gram positive (Staphylococcus aureus) and pathogenic gram negative bacteria (Escherichia coli, Salmonella and pseudomonas aeruginosa) was performed and the results were compared to those of a broad spectrum antibiotic (Chloramphinicol). 3+ and Dy 3+ were coordinated with two 15-crown-5 ligands and one picrate anion through its phenolic oxygen and the oxygen of it's ortho nitro group, except for Pr 3+ which was coordinated with only one 15-crown-5 ligand leaving three picrate anions as counter ions. In 18-crown-6 complexes both Pr 3+ and Nd 3+ were coordinated with one 18-crown-6 ligand leaving all the three picrate anions as counter ions outside the coordination sphere, except for the Dy 3+ complex which was coordinated with one 18-crown-6 ligand and one picrate anion.

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.nH 2 O , 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)]Pic 2 .nH 2 O 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).