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SUMMARY:Prof. Jonathan De Roo: From the synthesis and surface chemistry of
  oxo clusters to the precise composition of Metal Organic Frameworks
DTSTART:20251120T110000
DTEND:20251120T120000
DTSTAMP:20260525T080150Z
UID:03a63dc460593393b9d7152af5a28b81a8ffa9ff6fdb29e0bd0b16fe
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Jonathan De Roo\,\nDepartment of Chemistry\,\nUniversity
  of Basel\nAbstract : Zirconium and hafnium oxo clusters are building bloc
 ks for MOFs\, 3D-printing and polymers composites. However\, their synthes
 is is often a matter of trial and error\, and new structures are hard to d
 esign retrosynthetically.\nHere\, we study the nonaqueous formation mechan
 ism of the prototypical M6O4(OH)4(OOCR)12 (M = Zr or Hf) clusters.  In th
 e reaction of metal alkoxide with excess carboxylic acid\, an asymmetric t
 rinuclear complex is transiently formed. The reaction produces ester as by
 -product and we determine that precisely 1.33 equivalent of ester is requi
 red for every Zr atom to reach full yield of the oxo cluster. The esterifi
 cation can be divided in a fast and slow process and the proposed mechanis
 m is supported by kinetic modeling. We use our mechanistic insight to rede
 sign oxo cluster synthesis with higher reaction rates\, more economical pr
 ecursors\, more sustainable solvents and higher atom economy\, all at room
  temperature at gram scale. Furthermore\, we use precision hydrolysis to s
 ynthesize the elusive bimetallic Zr/Hf oxo clusters\, and to expand ration
 al oxo cluster synthesis to the group 5.\nWe leverage the atomically preci
 se nature of oxo clusters to gain fundamental insight into the thermodynam
 ics of ligand binding: carboxylates\, phosphonates\, dialkylphosphinates\,
  and monosubstituted phosphinates. Dialkylphosphinic acids are too sterica
 lly hindered to yield complete ligand exchange. Monoalkyl or monoaryl phos
 phinic acids do replace carboxylates quantitatively. Phosphonic acids caus
 e a partial structural reorganization of the metal oxo cluster into amorph
 ous metal phosphonate\, showing the challenge in preparing Zr phosphonate 
 metal–organic frameworks.\nFinally\, we present a rigorous yet simple me
 thod for the accurate determination of a MOF's minimal formula. By combini
 ng quantitative nuclear magnetic resonance (NMR) and ultraviolet-visible (
 UV–vis) spectroscopy data with thermogravimetric analysis (TGA)\, the mi
 nimal formula of several MOFs – MOF-808(Zr)\, UiO-66(Zr)\, UiO-66(Ce)\, 
 MOF-5(Zn)\, MIL-125(Ti)\, and MIL-100(Fe) – are constructed.\n\n\nBio : 
 Jonathan De Roo was born in 1989 in Belgium. He studied chemistry at Ghent
  University and obtained his PhD on the surface chemistry of metal oxide n
 anocrystals in 2016 under supervision of Prof. Isabel Van Driessche\, Prof
 . Zeger Hens and Prof. José Martins. During his PhD\, he conducted a thre
 e month research stay in the lab of Prof. Maksym Kovalenko to study the su
 rface of CsPbBr3 nanocrystals. He was a postdoctoral researcher at Columb
 ia University (USA) for 2 years\, working on crystallization mechanisms an
 d custom-made ligands under supervision of Prof. Jonathan Owen. Before ass
 uming his position at the University of Basel as assistant professor in Se
 ptember 2019\, he spent one more year as post-doctoral researcher at Ghent
  University.  He was promoted to Associate Professor with tenure in 2024
 .\n\n 
LOCATION:Tseuzier https://plan.epfl.ch/?room==I17%204%20K2 https://epfl.zo
 om.us/j/65378030944
STATUS:CONFIRMED
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