Harnessing Organometallic Au(III) Complexes as Precision Scaffolds for Next-Generation Therapeutic and Imaging Agents.

Au(III) organometallic complexes, particularly cyclometalated Au(III) compounds, have emerged as powerful tools in catalysis and bioinorganic chemistry, offering unique reactivity distinct from their Au(I) counterparts. Among their most interesting transformations, C-S cross-coupling reactions have become a selective strategy for cysteine arylation, enabling site-specific modifications of peptides and proteins. This review provides a comprehensive overview of cyclometalated Au(III) complexes in C-S bond formation, detailing the mechanistic insights, ligand effects, and electronic factors that dictate their reactivity. The role of ancillary ligands in tuning stability and selectivity is critically assessed, alongside advancements in structural modifications that enhance catalytic efficiency. Beyond fundamental C-S cross-coupling, the broader applications of these Au(III) complexes are explored, including enzyme inhibition, metabolic disruption, and transmembrane protein modulation, with implications in anticancer therapy, antimicrobial strategies, and in vivo catalytic transformations. By bridging fundamental organometallic reactivity with innovative biomedical applications, this review highlights the potential of cyclometalated Au(III) complexes as next-generation catalysts for both synthetic and therapeutic innovations.