Self-assembled nanostructures of specially designed Schiff-bases and their zinc complexes: Preparation, characterization and photoluminescence property

The paper presents a synthesis of poly(l-lactide) with bacteriostatic properties. This polymer was obtained by ring-opening polymerization of the lactide initiated by selected low-toxic zinc complexes, Zn[(acac)(L)H2O], where L represents N-(pyridin-4-ylmethylene) tryptophan or N-(2-pyridin-4-ylethylidene) phenylalanine. These complexes were obtained by reaction of Zn[(acac)2 H2O] and Schiff bases, , the products of the condensation of amino acids and 4-pyridinecarboxaldehyde. The composition, structure, and geometry of the synthesized complexes were determined by NMR and FTIR spectroscopy, elemental analysis, and molecular modeling. Both complexes showed the geometry of a distorted trigonal bipyramid. The antibacterial and antifungal activities of both complexes were found to be much stronger than those of the primary Schiff bases. The present study showed a higher efficiency of polymerization when initiated by the obtained zinc complexes than when initiated by the zinc(II) acetylacetonate complex. The synthesized polylactide showed antibacterial properties, especially the product obtained by polymerization initiated by a zinc(II) complex with a ligand based on l-phenylalanine. The polylactide showed a particularly strong antimicrobial effect against Pseudomonas aeruginosa, Staphylococcus aureus, and Aspergillus brasiliensis. At the same time, this polymer does not exhibit fibroblast cytotoxicity.

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Synthesis, Structures, and Antibacterial Activities of Two Methanol Coordinated Zinc Complexes with Tetradentate Bis-Schiff Bases

Russian Journal of Coordination Chemistry ◽

10.1134/s1070328417100025 ◽

2017 ◽

Vol 43 (10) ◽

pp. 663-669

Author(s):

L. F. Cai

Keyword(s):

Schiff Bases ◽

Antibacterial Activities ◽

Zinc Complexes

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Studies in the stereochemistry of zinc(II). VI. Zinc complexes with quadridentate Schiff bases

Australian Journal of Chemistry ◽

10.1071/ch9670885 ◽

1967 ◽

Vol 20 (5) ◽

pp. 885 ◽

Cited By ~ 37

Author(s):

GE Batley ◽

DP Graddon

Keyword(s):

Schiff Bases ◽

Infrared Spectra ◽

Zinc Complexes ◽

Steric Effects ◽

Pyridine Solution ◽

Carbon Chains ◽

Tetrahedral Environment ◽

Oxygen Atoms

Zinc complexes have been prepared with Schiff bases formed from salicylaldehyde and polymethylenediamines with chains of 2-9 carbon atoms. The anhydrous zinc complexes of ligands with 2-3 carbon chains readily form 1 : 1 adducts with water or bases such as pyridine; the ultraviolet and infrared spectra of these anhydrous compounds indicate that they are polymeric with bridging oxygen atoms, the zinc being 5-coordinate. The zinc complexes of ligands with carbon chains of four or more atoms do not form adducts, even in pyridine solution, and their spectra show that none of the oxygen atoms is bridging, the zinc being 4-coordinate. The stereochemistry of the zinc appears to be determined solely by steric effects: when the ligand is such that 4-coordination can produce a tetrahedral environment, further coordination does not occur; when 4-coordination cannot produce a tetrahedral environment, 5- coordination always occurs.

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