Synthesis, characterization and antibacterial activities of Pr (III)‎, Nd (III)‎ and Dy (III)‎ picrates with crown compounds

Other Title(s)

تحضير و تشخيص و دراسة الفعالية البكتيريا لبكرات (III)‎ Pr و (III)‎ Nd و (III)‎ Dy مع المركبات التاجية

Dissertant

Samin, Mustafa Qahtan

Thesis advisor

Abbas, Muhammad Husayn
al-Abdaly, Basim Ibrahim Mahdi

University

University of Baghdad

Faculty

College of Science

Department

Chemistry Department

University Country

Iraq

Degree

Master

Degree Date

2014

English Abstract

This work involved the synthesis, characterization and antibacterial activity of new complexes of lanthanide picrates with some crown ethers and cryptand macrocyclic ligands.

Lanthanide picrates were prepared as Pr(Pic)3.6H2O, Nd(Pic)3.6H2O and Dy(Pic)3.3H2O from the reaction of the corresponding lanthanide oxides with picric acid in aqueous media.

The resulted solid picrates are quite stable in air and posses the characteristic yellow color of the picrate ion.

The lanthanide picrates were characterized by elemental analysis (CHN), IR, UV – Vis., and magnetic properties.

The metal content was determined using ICP – AES technique.

Their elemental analysis agreed quite well with the above formulae.

Complexes of lanthanide picrates with three cyclic polyethers (15-crown-5, 18-crown-6 and benzo-18-crown-6) and one bicyclic macromolecule cryptand (2,2,1) have been prepared.

These complexes were characterized by elemental analysis (CHN), thermal analysis (DTG and DTA), FTIR, UV – Vis., 1H-NMR, 13C-NMR, molar conductance and magnetic properties.

The metal content was determined using ICP – AES technique.

The isolated solid complexes were colored (dark orange – yellow) which are the characteristic colors of the picrate compounds, These complexes have the following suggested formulae: [Pr(15C5)](Pic)3.H2O, [Nd(15C5)2(Pic)](Pic)2.5H2O, [Dy(15C5)2(Pic)](Pic)2 .2H2O, [Pr(18C6)](Pic)3, [Nd(18C6)](Pic)3, [Dy(18C6)(Pic)](Pic)2.3H2O, [Pr(B18C6)(Pic)2]Pic.2H2O, i 20 [Nd(B18C6)(Pic)2]Pic.H2O, [Dy(B18C6)(Pic)2]Pic.H2O, [Pr(221)(Pic)](Pic)2.H2O, [Nd(221)(Pic)](Pic)2.7H2O and [Dy(221)(Pic)](Pic)2.2H2O.

The results of the elemental analysis, thermal analysis, molar conductance and the spectroscopic methods agreed quite well with the above suggested formulae and supported their structures.

The prepared complexes are of 1:1 and 1:2 metal:ligand types.

These ratios depend upon the relative sizes of the cavity in the macrocyclic ligands and of the cation diameter.

The proposed structures of the 1:1 (M:L) complexes suggested that lanthanide ion is encapsulated in the cavity of the ligand except for the complex of Pr-15-crown-5, in which the metal is located outside and above the cavity.

The structures of the 1:2 (M:L) complexes were proposed to be of the sandwich type, where the lanthanide ion is located between two ligands.

The prepared complexes were also investigated for their antibacterial activity in-vitro against four types of pathogenic bacteria, three of the gram negative type (Escherichia coli, Salmonella and pseudomonas aeruginosa) and one gram positive (staphylococcus aureus).

This area is not much explored for the common crown and cryptand compounds.

The tested complexes showed very good promising and encouraging results when compared to the activity of the broad spectrum antibiotic (Chloramphenicol).

The results showed that the antibacterial activities were varied from one complex to another.

Actually chloramphenicol showed no activity at all against the pathogenic gram negative bacterium (pseudomonas aeruginosa) which is known to possess resistance against many types of antibiotics, while all the complexes showed very good inhibition zones against this type of bacteria.

Still a study of their ii 21 cytotoxicity is required alongside many in-vivo studies in order to estimate their behavior in biological systems and the possible side effects caused by them, since the results obtained from their in-vitro test place them as potential antibiotic drugs.

Their activity is believed to rise from one of the following mechanisms; first the chelation theory, this mechanism suggests that the activity is increases upon chelation due to the sharing of the lanthanide‟s positive charge with the donor atoms of the ligand.

Second, DNA binding, third, DNA cleavage and fourth, weakening of the bacterial outer membrane.

iii

Main Subjects

Chemistry

Topics

• Chemistry
• Organic chemistry
• Bacterioses
• Chemotherapy
• Antibacterial agents

No. of Pages

202

Table of Contents

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-599759