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

Abstract

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(OiPr)4 resulted in the compounds Zr5O4(BrC(CH3)2COO)10(OnPr)2(nPrOH)4 and Ti6O4(BrC(CH3)2COO)8(OiPr)8. The reaction of 2-bromopropionic acid with VO(OiPr)3 resulted in the cluster V3O3(BrC(CH3)COO)6(HOiPr). 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.

Organic Reaction Pathways in the Nonaqueous Synthesis of Metal Oxide Nanoparticles

“…[6,177] To achieve perfectly defined structures, the water required for cluster formation is generated in situ through esterification or aldolization reactions in the presence of chelating or bridging organic ligands as stabilizing agents. The preparation involved the use of the corresponding metal isopropoxides in carboxylic acids, giving access to various titanium-oxo-isopropoxo clusters, [206] a niobium-oxoacetate complex, [207] and several titanium-, zirconium-, and vanadium-oxo clusters, [208] to name but a few. Two possible formation mechanisms based on direct esterification (intracoordination-sphere mechanism, i.e., water is only virtually formed) or esterification between the slowly exchanged organic acid and the alcohol molecules (water is produced in situ) were proposed.…”

Precise surface structure control of inorganic solid and metal oxide nanoparticles through surface-initiated radical polymerization

“…In addition, the advantage of polymer brushes, especially in a surface-initiated approach, over other surface modification methods is their mechanical and chemical robustness, coupled with a high degree of synthetic flexibility towards the introduction of a variety of functional groups. Therefore, various types of polymer brushes have already been prepared by surface-initiated controlled radical polymerization from functionalized inorganic particles such as silica [11,12], gold [13,14], aluminum oxide [15], and titanium oxo clusters [16].…”

Plastic electronic devices: From materials design to device applications

“…However, silicon oxide has a relatively low dielectric constant (4.5). Much less work has been done on core shell architectures with other inorganic oxide nanoparticles [51], especially high K inorganic oxides such as titanium dioxide. A high K inorganic oxide-core-polymer-shell material would be homogenous on the tens of nanometers scale, and therefore exhibit homogeneity in films, a desirable prerequisite for subsequent well-ordered semiconductor film deposition.…”