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SUMMARY:Zirconium and hafnium oxide nanocrystals and oxo clusters - Prof. 
 Jonathan de Roo
DTSTART:20230302T150000Z
DTEND:20230302T160000Z
UID:TALK196948@talks.cam.ac.uk
CONTACT:Julie Smith
DESCRIPTION:Colloidal nanocrystals are usually hybrid inorganic-organic ob
 jects. They have an inorganic\, crystalline core which is capped by a laye
 r of organic surfactants. Metal oxide nanocrystals find application in sol
 ar cells\, batteries\, bio-imaging\, etc. On the other hand\, oxo clusters
  are building blocks in metal organic Frameworks (MOFs) with exciting cata
 lytic properties. \n\nFirst\, we introduce surfactant-assisted synthesis o
 f colloidal nanocrystals and the (undesired) chemistry that can occur with
  solvents and ligands. Second\, we elaborate on the precursor chemistry du
 ring the synthesis of zirconium and hafnium oxide nanocrystals. After esta
 blishing an E1 elimination mechanism\, we focus on the crystallization mec
 hanism and find that an amorphous phase precedes the crystalline nanoparti
 cles. Third\, we develop a comprehensive picture of the surface chemistry 
 of these metal oxide nanocrystals. We establish ligand exchange rules in b
 oth nonaqueous and aqueous media. As such\, we find the optimal binding mo
 iety for physiological conditions\; nitrodopamine derivatives. Tailoring t
 he surface chemistry allows to use hafnium oxide nanocrystals as contrast 
 agent in Computed Tomography (CT) imaging. We will discuss both in vivo an
 d ex vivo applications of such contrast agents. Finally\, we take the oxo 
 clusters out of the MOF and consider it an atomically precise nanocrystal.
  Using the same ligands as for nanocrystals\, the clusters are endowed wit
 h the same solubility properties and become useful catalysts. The cluster-
 catalyzed reaction has a five times higher rate than the nanocrystal-catal
 yzed reaction. To analyze the soluble clusters\, we use X-ray total scatte
 ring and Pair Distribution Function analysis. \n\nWe thus present here a c
 omprehensive overview of oxide nanochemistry\, focusing on group 4 metals.
  \n
LOCATION:Goldsmiths 1 &amp\; https://us06web.zoom.us/j/81688365420?pwd=b3R
 pdHgxNVhWbWQrbXluMUxYNWVtQT09 Meeting ID: 816 8836 5420 Passcode: 047859
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