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Metal complexes of macrocyclic schiff-base ligand: preparation, characterisation, and biological activity.

Ahmed RM, Yousif EI, Hasan HA, Al-Jeboori MJ - ScientificWorldJournal (2013)

Bottom Line: Biological activity of the ligand and its metal complexes against Gram positive bacterial strain Staphylococcus aureus and Gram negative bacteria Escherichia coli revealed that the metal complexes become more potentially resistive to the microbial activities as compared to the free ligand.However, these metal complexes do not exhibit any effects on the activity of Pseudomonas aeruginosa bacteria.There is therefore no inhibition zone.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, College of Education, Ibn Al-Haitham, University of Baghdad, P.O. Box 4150, Adhamiyah, Baghdad, Iraq.

ABSTRACT
A new macrocyclic multidentate Schiff-base ligand Na4L consisting of two submacrocyclic units (10,21-bis-iminomethyl-3,6,14,17-tricyclo[17.3.1.1]tetracosa-1(23),2,6,8,10,12(24),13,17,19,21,-decaene-23,24-disodium) and its tetranuclear metal complexes with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) are reported. Na₄L was prepared via a template approach, which is based on the condensation reaction of sodium 2,4,6-triformyl phenolate with ethylenediamine in mole ratios of 2 : 3. The tetranuclear macrocyclic-based complexes were prepared from the reaction of the corresponding metal chloride with the ligand. The mode of bonding and overall geometry of the compounds were determined through physicochemical and spectroscopic methods. These studies revealed tetrahedral geometries about Mn, Co, and Zn atoms. However, square planar geometries have been suggested for Ni(II) and Cu(II) complexes. Biological activity of the ligand and its metal complexes against Gram positive bacterial strain Staphylococcus aureus and Gram negative bacteria Escherichia coli revealed that the metal complexes become more potentially resistive to the microbial activities as compared to the free ligand. However, these metal complexes do not exhibit any effects on the activity of Pseudomonas aeruginosa bacteria. There is therefore no inhibition zone.

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Synthesis scheme of the Schiff-base ligand Na2L and it's complexes.
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sch1: Synthesis scheme of the Schiff-base ligand Na2L and it's complexes.

Mentions: A template approach was implemented to obtain the Schiff-base Na4L in a reasonable yield (Scheme 1). Using Na+ ion was found to be essential to form the ligand since otherwise only a polymeric mixture, partially soluble in hot DMF, was recovered via direct approach. The ligand was prepared from the reaction of sodium 2,4,6-triformyl phenolate (STFP) with ethylenediamine in mole ratios 2 : 3, respectively. The Schiff-base is soluble with stirring in DMF and DMSO but not in other common organic solvents. The ligand was characterised by elemental analysis (Table 1), IR (Table 2) and UV-Vis (Table 3) spectroscopy, and 1H- and 13C-NMR spectroscopy. The IR spectrum of the free Schiff-base shows characteristic bands at 1632, 1622, 1350, and 1031 cm−1 due to the ν(C=N), ν(phenoxide), and ν(C–O) functional groups, respectively. The UV-Vis spectrum of Na4L exhibits an intense absorption peak at 295 nm, assigned to π → π*. The peak at 322 nm assigned to n → π* transition.


Metal complexes of macrocyclic schiff-base ligand: preparation, characterisation, and biological activity.

Ahmed RM, Yousif EI, Hasan HA, Al-Jeboori MJ - ScientificWorldJournal (2013)

Synthesis scheme of the Schiff-base ligand Na2L and it's complexes.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3713367&req=5

sch1: Synthesis scheme of the Schiff-base ligand Na2L and it's complexes.
Mentions: A template approach was implemented to obtain the Schiff-base Na4L in a reasonable yield (Scheme 1). Using Na+ ion was found to be essential to form the ligand since otherwise only a polymeric mixture, partially soluble in hot DMF, was recovered via direct approach. The ligand was prepared from the reaction of sodium 2,4,6-triformyl phenolate (STFP) with ethylenediamine in mole ratios 2 : 3, respectively. The Schiff-base is soluble with stirring in DMF and DMSO but not in other common organic solvents. The ligand was characterised by elemental analysis (Table 1), IR (Table 2) and UV-Vis (Table 3) spectroscopy, and 1H- and 13C-NMR spectroscopy. The IR spectrum of the free Schiff-base shows characteristic bands at 1632, 1622, 1350, and 1031 cm−1 due to the ν(C=N), ν(phenoxide), and ν(C–O) functional groups, respectively. The UV-Vis spectrum of Na4L exhibits an intense absorption peak at 295 nm, assigned to π → π*. The peak at 322 nm assigned to n → π* transition.

Bottom Line: Biological activity of the ligand and its metal complexes against Gram positive bacterial strain Staphylococcus aureus and Gram negative bacteria Escherichia coli revealed that the metal complexes become more potentially resistive to the microbial activities as compared to the free ligand.However, these metal complexes do not exhibit any effects on the activity of Pseudomonas aeruginosa bacteria.There is therefore no inhibition zone.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, College of Education, Ibn Al-Haitham, University of Baghdad, P.O. Box 4150, Adhamiyah, Baghdad, Iraq.

ABSTRACT
A new macrocyclic multidentate Schiff-base ligand Na4L consisting of two submacrocyclic units (10,21-bis-iminomethyl-3,6,14,17-tricyclo[17.3.1.1]tetracosa-1(23),2,6,8,10,12(24),13,17,19,21,-decaene-23,24-disodium) and its tetranuclear metal complexes with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) are reported. Na₄L was prepared via a template approach, which is based on the condensation reaction of sodium 2,4,6-triformyl phenolate with ethylenediamine in mole ratios of 2 : 3. The tetranuclear macrocyclic-based complexes were prepared from the reaction of the corresponding metal chloride with the ligand. The mode of bonding and overall geometry of the compounds were determined through physicochemical and spectroscopic methods. These studies revealed tetrahedral geometries about Mn, Co, and Zn atoms. However, square planar geometries have been suggested for Ni(II) and Cu(II) complexes. Biological activity of the ligand and its metal complexes against Gram positive bacterial strain Staphylococcus aureus and Gram negative bacteria Escherichia coli revealed that the metal complexes become more potentially resistive to the microbial activities as compared to the free ligand. However, these metal complexes do not exhibit any effects on the activity of Pseudomonas aeruginosa bacteria. There is therefore no inhibition zone.

Show MeSH
Related in: MedlinePlus