Heterometallic Multinuclear Ruthenium Complexes as Cytotoxic Agents

The design of multitargeted drug candidates has recently emerged as a highly attractive area of research. Numerous heterometallic compounds have been developed to enhance both the biological efficacy and physicochemical properties of monometallic metallodrugs. Combining classical transition metals with established antitumor activity, such as Pt, Ru, and Au, with other metal-based fragments offers the potential to generate complex compounds with improved pharmacokinetic and pharmacodynamic profiles. Incorporating different bioactive metal cations within a single molecular framework may enhance anticancer activity through metal-specific interactions with distinct biological targets or through improved physicochemical characteristics of the resulting heteronuclear complexes. Recent studies have underscored the significant progress and promising impact of this multitargeted strategy, particularly in systems that combine ruthenium with other biologically active metal centers. This approach may enable selective biological targeting and help overcome drug resistance. This review compiles and analyzes reported ruthenium-based heteronuclear complexes, offering a comprehensive and critical assessment of recent advances in the rational design and synthesis of novel multinuclear compounds as potential chemotherapeutic agents. Particular emphasis is placed on understanding structure–activity relationships, mechanistic pathways, and the role of metal–metal and metal–ligand interactions in modulating biological responses. The findings summarized herein highlight the remarkable efficacy of a wide range of multinuclear ruthenium anticancer complexes and support the hypothesis that synergistic and/or cooperative interactions between distinct metal-based fragments can significantly enhance pharmacological performance, including improved selectivity, stability, and cellular uptake. Furthermore, emerging insights into their modes of action, resistance profiles, and potential for targeted delivery underscore their promise as viable alternatives to conventional therapies. Overall, this dynamic and rapidly evolving field is poised to inspire continued interdisciplinary research and drive the development of next-generation metallodrugs with improved therapeutic indices and clinical potential.