Abstract

LONDONO-MOSQUERA, Juan-David  and  POLO-CERON, Dorian. Study of Novel Metal Complexes Derived From a Flexible Polydentate Ligand for Biological and Biomedical Applications. Ciencia en Desarrollo [online]. 2022, vol.13, n.2, pp.131-157.  Epub Apr 28, 2023. ISSN 0121-7488.  https://doi.org/10.19053/01217488.v13.n2.2022.14087.

This work shows the synthesis of four new lanthanide complexes of Gd(III) (1), Eu(III) (2), Dy(III) (3) and Yb(III) (4) ions, using two polydentate ligands F and L in order to evaluate their potential application on the contrast-imaging by fluorescence microscopy (MF), nuclear magnetic resonance (RMI) and as antibacterial agents. We propose a structure where both ligands are bound to the metal centre through -OH, -N- and -COO- groups, exhibiting an apparent coordination number of 7. Moreover, r1 molar relaxivities obtained demonstrates that all the complexes had the capability to accelerate longitudinal relaxation times (T1) of water, with a r1 value of 6.45 mmol-1·L-1·s-1 for compound 1, which was higher than r1 of 2.25 mmol-1·L-1·s-1 corresponding to commercial drug Dotarem® employed for RMI. Furthermore, all quantum yields of fluorescence, in reference to fluorescein, where lower than 1 %, showing a poor performance in emission processes of visible radiation. Stability constants determined as (- log[kap]) were between 21 and 18, being even better than some contrast agents. Compound 2 managed to inhibit the growth of Gram-positive and Gram-negative bacterial strains evaluated with minimum inhibitory concentrations (MICs) of up to 250 mg·L-1, in general the high MICs suggested that the complexes obtained could have a potential application in prokaryotic cell fluorescence contrast. Finally, DNA binding experiments showed that all complexes had the capability to bind DNA strands by a possible intercalation mechanism.

Keywords : Polydentate ligand; Lanthanide ions; Contrast agent; Nuclear magnetic resonance; Fluorescent microscopy.

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