Cluster dynamics of heterometallic trinuclear clusters during ligand substitution, redox chemistry, and group transfer processes

Stepwise metalation of the hexadentate ligand ^tbsLH₆ (^tbsLH₆ = 1,3,5-C₆H₉(NHC₆H₄-o-NHSiMe₂^tBu)₃) affords bimetallic trinuclear clusters (^tbsL)Fe₂Zn(thf) and (^tbsL)Fe₂Zn(py). Reactivity studies were pursued to understand metal atom lability as the clusters undergo ligand substitution, redox chemistry, and group transfer processes. Chloride addition to (^tbsL)Fe₂Zn(thf) resulted in a mixture of species including both all-zinc and all-iron products. Addition of ArN₃ (Ar = Ph, 3,5-(CF₃)₂C₆H₃) to (^tbsL)Fe₂Zn(py) yielded a mixture of two trinuclear products: (^tbsL)Fe₃(μ³-NAr) and (^tbsL)Fe₂Zn(μ³-NAr)(py). The two imido species were separated via crystallization, and outer sphere reduction of (^tbsL)Fe₂Zn(μ³-NAr)(py) resulted in the formation of a single product, [2,2,2-crypt(K)][(^tbsL)Fe₂Zn(μ³-NAr)]. These results provide insight into the relationship between heterometallic cluster structure and substitutional lability and could help inform both future catalyst design and our understanding of metal atom lability in bioinorganic systems.