Ferrocene and Organotin (IV) Conjugates Containing Amino Acids and Peptides: A Promising Strategy for Searching New Therapeutic and Diagnostic Tools

Organometallic complexes are an important class of synthetic reagents and are of great interest due to their versatility and wide biological application. The cationic nature of the coordination nucleus facilitates its interaction with biological molecules such as amino acids, proteins, and nucleic acids. The functionalization of peptides or amino acids with organometallic motifs is a novel strategy for the design and development of molecules with greater biological activity, stability in biological environments, and selectivity for specific targets, which make them valuable tools for designing and obtaining molecules with therapeutic applications. The physicochemical properties of ferrocene make it ideal for drug development, due to its structure, stability in aqueous solutions, redox properties, and low toxicity. In the same way, organotin (IV) derivatives have great potential for drug development because of their multiple biological activities, wide structural versatility, high degree of stability, and low toxicity. However, the synthesis of these drugs based on organometallic molecules containing ferrocene or organotin (IV) is quite complex and represents a challenge nowadays; for this reason, it is necessary to design and implement procedures to obtain molecules with a high degree of purity, in sufficient quantities, and at low cost. This review describes the strategies of synthesis used up to now for the preparation of organometallic amino acids and peptides containing ferrocene or organotin (IV) derivates, as well as their impact on the development of therapeutic agents.