Hybrid Inorganic−Organic Core−Shell Nanoparticles from Surface-Functionalized Titanium, Zirconium, and Vanadium Oxo Clusters

Novel surface-functionalized metal oxo clusters were obtained using an in situ surface-modification method based on the sol−gel process. A reaction of 2-bromoisobutyric acid with Zr(OPr) 4 or Ti(O i Pr) 4 resulted in the compounds Zr 5 O 4 (BrC(CH 3 ) 2 COO) 10 (O n Pr) 2 ( n PrOH) 4 and Ti 6 O 4 (BrC(CH 3 ) 2 COO) 8 (O i Pr) 8 . The reaction of 2-bromopropionic acid with VO(O i Pr) 3 resulted in the cluster V 3 O 3 (BrC(CH 3 )COO) 6 (HO i Pr). All obtained compounds have in common that the organic functionalities are exclusively located on the surface of the well-defined sub-nanometer metal oxo clusters. The prepared compounds were successfully used as macroinitiators in atom transfer radical polymerizations (ATRP) and produced inorganic−organic core−shell nanoparticles.