Multinuclear Platforms featuring Redox-Active Ligands – Synthesis & Reactivity Studies

• Applicant: Professor Dr. Jarl Ivar van der Vlugt
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 570083135

Organometallic and coordination chemistry serve as pillars for homogeneous catalysis. Current synthetic catalyst design principles are still often based on mononuclear designs and metal-centered reactivity. In stark contrast, many metalloenzyme active sites are known to combine and exploit multinuclear reaction centers in combination with reactive ligand spheres, thereby offering a much broader reactivity palette compared to mononuclear complexes. The construction of molecular multimetallic architectures is a very vibrant field that encompasses different strategies, including ways to synthetically access heterobimetallic species. However, controllably tuning metal−metal interactions (i.e. bonding, electronic communication or cooperative reactivity) for selective substrate activation presents several challenges, as they often compete with metal−ligand bonding. Hence, under (pseudo-)catalytic conditions, both mononuclear and dinuclear species may coexist. Furthermore, many of the systems that have permitted metal−metal interactions to be stabilized employ sterically encumbering ligands that are poorly suited for follow-up (catalytic) reactivity. Ligand-centered reactivity can alleviate this dichotomy. Redox-active ligands are organic frameworks that can undergo reversible shuttling between at least two well-defined redox-states. Only a subset of known dinuclear systems allow organic substrates to access the apical position of the metal−metal bond, and fewer still permit substrates to bind across the two metals.There remain substantial opportunities for the design of multinuclear systems that balance stability with reactivity toward external substrates. This DFG project will address a current knowledge gap by exploring synthetic avenues to access and exploit the extended chemical space that becomes available when metal-metal cooperativity and ligand-centered redox-activity is combined within well-defined homo- and heteromultinuclear architectures. Tuning of the electronic communication and the chemical interplay between two different metal centers by means of controlled ligand redox switching and the correlated modification of reactivity displayed by such bimetallic species are ill-explored strategies to date. Several questions concerning the potential and scope of this methodology for selective substrate activation and reactivity will be addressed in this proposal. A set of well-defined di- and trinuclear heterobimetallic complexes will be synthesized and characterized, their stoichiometric chemistry explored and their redox-tunable catalytic competence for radical-type C-N bond formation and C-C bond coupling reactions interrogated. As such, ligand-centered reactivity within different types of multinuclear manifold will offer opportunities that go beyond the well-known (organometallic) chemistry of mononuclear late transition metals and their current-day concepts to forge chemical bonds in a stochiometric or catalytic manner.

• DFG Programme: Research Grants