|Monday, July 18|
Modulation of the properties of gold complexes through ligand design
* M. Concepción Gimeno, CSIC-Universidad de Zaragoza, Spain
The chemistry of gold has experienced a great development mainly because the discovery of the properties of its complexes . Gold compounds have been well known to be useful catalysts for small molecule activation and in organic synthesis, while their impacts in materials science and medicine is continuously increasing. To facilitate this extraordinary progress in the chemistry of gold, the synthesis and design of novel strong donor ligands have been crucial. Such strong donor ligands combine electronic and steric properties that are easily modulated, which is a key point to stabilize and to confer the gold complexes with interesting properties. This presentation will highlight the design of several types of gold complexes that have been developed in our group. Ligand selection is a crucial factor to obtain complexes with the desired properties. In first place, looking for the preparation of gold compounds with biological activity, the use of ligands favoring complexes with improved stability and solubility in the biological media could provide better activities . Functionalization of these ligands to achieve an easier localization of the target by the complex appears as an excellent approach towards gold metallodrugs. The presence of two metallic fragments exerts a cooperative effect in the cytotoxic activity and properties of the final complexes, which could overcome cellular resistance because of the possibility of combining the different intrinsic mechanism of action of each metallic fragment. Additionally, the possibility to move from single to multi-targeted therapy for cancer treatment have revolutionized the concept of oncological medicine. The single-target therapy is vanishing in favor of a multi-target approach, where new drugs can simultaneously target different molecules and gold complexes are excellent examples for this type of approach. In the second place, research in light emitting materials have experienced a substantial growth during the last few years and it has become one of the most important topics in transition metal chemistry. Potential applications of luminescent compounds in sensors, OLEDs, photocatalysis and medicine (among other areas) explain the growing research in such species . The synthesis and potential applications of gold complexes will be commented. The variety of ligands with different donor centers that can coordinate to gold in their different oxidation states will permit the tuning of the emission energy almost over the whole of the visible spectrum. Additionally, within the gold complexes with biological activity the incorporation of an organic or organometallic chromophore group would give rise to luminescent complexes, which would allow visualizing the localization inside the cell, providing crucial information such as cellular uptake, biodistribution and/or bioaffinity. This combination of a visualization agent with a selected therapeutic, known as an optical theranostic or a trackable agent, would be able to provide relevant information regarding its biological interplay .  R. P. Herrera, M. C. Gimeno, Chem. Rev. 2021, 121, 8311–8363.  M. Mora, M. C. Gimeno, R. Visbal, Chem. Soc. Rev. 2019, 48, 447-462.  R. Visbal, M. C. Gimeno, Chem. Soc. Rev. 2014, 43, 3551-3574.  V. Fernández-Moreira, M. C. Gimeno, Chem. Eur. J. 2018, 24, 3345-3353.