Abstract

Hussein Al-Amery, B. Ibrahim Al-Abdaly and M. Kahtan Albayaty

DOI : http://dx.doi.org/10.13005/ojc/320228

Complexes of some lanthanide picrates (Ln³⁺ = Pr³⁺, Nd³⁺ and Dy³⁺) with 15-crown-5 and 18-crown-6 were synthesized and characterized by elemental analysis, ICP-AES, FTIR, ¹H-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). The  complexes of 15-crown-5 have the general formula [Ln(15C5)₂(Pic)]Pic₂.nH₂O where (Ln³⁺ = Nd³⁺ and Dy³⁺), (Pic = Picrate anion) and (n = 2 or 4) except for Pr³⁺ complex which has the formula [Pr(15C5)]Pic₃.H₂O , the 18-crown-6 complexes have the general formula [Ln(18C6)]Pic₃ where (Ln³⁺ = Pr³⁺ and Nd³⁺) except for Dy³⁺ complex which has the formula [Dy(18C6)(Pic)]Pic₂.3H₂O. In 15-crown-5 complexes both Nd³⁺ and Dy³⁺ 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 Pr³⁺ which was coordinated with only one 15-crown-5 ligand leaving three picrate anions as counter ions. In 18-crown-6 complexes both Pr³⁺ and Nd³⁺ were coordinated with one 18-crown-6 ligand leaving all the three picrate anions as counter ions outside the coordination sphere, except for the Dy³⁺ complex which was coordinated with one 18-crown-6 ligand and one picrate anion.

crown ethers; lanthanides; picrates; supramolecular chemistry

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