'Weakly Ligated, Labile Ligand' Nanoparticles: The Case of Ir(0)n·(H+Cl–)m

It is of considerable interest to prepare weakly ligated, labile ligand (WLLL) nanoparticles for applications in areas such as chemical catalysis. WLLL nanoparticles can be defined as nanoparticles with sufficient, albeit minimal, surface ligands of moderate binding strength to meta-stabilize nanoparticles, initial stabilizer ligands that can be readily replaced by other, desired, more strongly coordinating ligands and removed completely when desired. Herein, we describe WLLL nanoparticles prepared from [Ir(1,5-COD)Cl]2 reduction under H2, in acetone. The results suggest that H+Cl–-stabilized Ir(0)n nanoparticles, herein Ir(0)n·(H+Cl–)a, serve as a WLLL nanoparticle for the preparation of, as illustrative examples, five specific nanoparticle products: Ir(0)n·(Cl–Bu3NH+)a, Ir(0)n·(Cl–Dodec3NH+)a, Ir(0)n·(POct3)0.2n(Cl–H+)b, Ir(0)n·(POct3)0.2n, and the γ-Al2O3-supported heterogeneous catalyst, Ir(0)n·(γ-Al2O3)a(Cl–H+)b. (where a and b vary for the differently ligated nanoparticles; in addition, solvent can ...