Lanthanide Complexes with N,N-Bis-(2-hydroxy-5-nitrobenzylidene)-1,2-phenylenediamine Schiff Base Ligand: Synthesis, Characterization, Photophysical Properties, and Biological Activity

Abstract

A series of lanthanides(III) complexes containing Schiff base ligand, {[LnL(NO 3 ).H 2 O]•xH 2 O {Ln: La, Pr, Nd, Sm, Eu, Gd, Tb, and Dy, H 2 L: N,N-bis-(2-hydroxy-5-nitro-benzylidene)-1,2-phenylenediamine Schiff base ligand}, have been synthesized by reaction of the ligand with Ln(NO 3 ) 3 •xH 2 O in the presence of NaOH.Structures of these complexes have been characterized by elemental analysis, molar conductivity, thermal gravimetric and various spectral methods (IR, UV-Vis, 1 H, and 13 C NMR). The proposed formula, of the complexes consists of one Ln(III) ion with the coordination number of seven. Two coordination sites are occupied by one bi-dentate nitrate anion, another site is occupied by one water molecule and the remaining four coordination sites are occupied by one deprotonated tetra-dentate ligand molecule. Fluorescence emission spectra of Ln(III) complexes exhibit ligand-centred emission peak with a blue shift compared with that of free H 2 L. This can be explained on the basis of ligand-to-metal charge transfer (LMCT) that occurs upon L -2 coordination to Ln(III) ions. Antibacterial activity of H 2 L and its Ln(III) complexes has been tested against some gram-positive and gram-negative bacterial strains.

СOMPLEXES OF Nd(III) AND 3d-METALS BASED ON ETHYLENEDIAMINEDISUCCINIC ACID AS POTENTIAL ANTIFUNGAL AGENTS

“…Complex compounds of polyaminocarboxylic acids with lanthanides and iron can be used in the therapy of oncological diseases, immunodeficiencies and blood diseases. Nit-rates [LnL(NO 3 ) 2 (H 2 O) 2 ](NO 3 ), (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er) with polydentate Schiff bases (L = N,N-bis(2-hydroxy-1-naphthylidene)-1,6-hexadimine), as well as hydrazine complexes of 3,3'-thiodipropanoates [M(N 2 H 5 )(tdp) 2 ] (M = La, Ce, Sm, Pr, Nd) by in vitro evaluation demonstrated high antimicrobial activity against six bacteria (Bacillus cereus, Staphylococcus aureus, Proteus vulgaris, Pseudomonas aeruginosa, Escherichia coli, Serratia species) and four fungi (Candida albicans, Aspergillus niger, Aspergillus fumigatus, Penicillium variance) [14][15][16].…”