Fatty acid capped, metal oxo clusters as the smallest conceivable nanocrystal prototypes

Abstract

Metal oxo clusters of the type M6O4(OH)4(OOCR)12 (M = Zr or Hf) are valuable building blocks for materials science.

Self-assembled metal-oxo clusters for sensitive and low-powered ultraviolet photodetectors

“…The diffraction peaks at 9.6°, 9.9°, and 12.9° correspond to (101), (110), and (002) planes of Zr 6 O 4 (OH) 4 subunit, respectively (CCDC-1051013), indicating the formation of ZOC. The conversion of Zr(OH) 4 to ZOC in the presence of HCOOH is described as follows: 17,18 …”

“…Conventionally, this binding is categorized into chelating coordination (Δ ν < 110 cm −1 ), bidentate bridging (Δ ν = 140–190 cm −1 ), and monodentate bridging (Δ ν > 200 cm −1 ). 18 Accordingly, the as-prepared ZOC with Δ ν = 177 cm −1 consists of one Zr 6 O 4 (OH) 4 core capped by HCOO − groups via the stable bidentate bridging as illustrated in Fig. 1c.…”

High-Concentration Self-Assembly of Zirconium- and Hafnium-Based Metal–Organic Materials

“…Previous reports indicate that α-branching on the capping carboxylic acid favors the formation of Zr 6 clusters over other possible structures. 39,42,48 Hypothesizing that very bulky capping carboxylates should enforce the correct node architecture, we identified the pivalate-capped cluster Zr 6 O 4 (OH) 4 (OPiv) 12 (OPiv − = pivalate), referred to herein as ZrPiv, as a promising yet hitherto unexplored potential MOF precursor. 49 Simply combining ZrCl 4 , pivalic acid (PivOH), and DMF under solvothermal conditions yielded large crystals of ZrPiv (see SI Section 4 for details).…”

The Surface Chemistry of Colloidal Nanocrystals Capped by Organic Ligands

“…Very small nanocrystals have a high curvature, which provides additional space, but sterics still play a role. 65 Take the X-for-X type exchange of oleate for other carboxylates on 3.5 nm CdSe nanocrystals:…”

“…Even on a flat surface, the density of surface atoms is higher than the maximum density of alkane chains and thus the ligand density is per definition limited by sterics. Very small nanocrystals have a high curvature, which provides additional space, but sterics still play a role …”