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SUMMARY:Microscopic Mechanism of Thermally Induced Ordered-Disordered Phas
 e transitions in Zeolitic Imidazolate Frameworks Revealed via Molecular Dy
 namics and Machine Learning Techniques - Prof. Rocio Semino\, Sorbonne Uni
 versity
DTSTART:20240122T140000Z
DTEND:20240122T143000Z
UID:TALK210673@talks.cam.ac.uk
CONTACT:Dr Philipp Pracht
DESCRIPTION:Metal-organic frameworks (MOFs) feature promising applications
  for important industrial and societal problems. In order to move forward 
 in our quest for developing new MOF materials\, we need to gain further mo
 lecular-level understanding on their transformations and phase transitions
 . In this presentation\, I will highlight our recent study[1] of the molec
 ular mechanism of ordered-disordered phase transitions undergone by two ze
 olitic imidazolate frameworks composed by Zn2+ and imidazolate: a porous (
 ZIF-4) and a dense\, non-porous (ZIF-zni) polymorph\, via a combination of
  data science and computer simulation approaches. Molecular dynamics simul
 ations were carried out at the atomistic level through the nb-ZIF-FF force
  field[2] that incorporates ligand–metal reactivity and relies on dummy 
 atoms to reproduce the correct tetrahedral topology around Zn2+ centres. S
 ymmetry functions computed over a database of structures of the four phase
 s\, were used as inputs to train a neural network that predicts the probab
 ilities of belonging to each of the phases at the local Zn2+ level with 90
 % accuracy. We find that the amorphization of ZIF-4 and the melting of ZIF
 -zni involve connectivity changes in the first neighbour ligands around th
 e central Zn2+ cations. In addition\, the former is a non-isotropic proces
 s and we trace back the origins of this behaviour to density and lability 
 of coordination bonds. These investigations are part of a larger project w
 here reactive processes of MOFs in solution are studied via a combination 
 of multiscale simulations and data science techniques (ERC starting grant\
 , MAGNIFY project [3]). \n\n[1] arXiv: 2311.16351\n\n[2] S. R. G. Balestra
  and R. Semino\; J. Chem. Phys\, 157\, 184502 (2022)\n\n[3] https://www.ro
 ciosemino.com/magnify-project
LOCATION:Zoom link: https://zoom.us/j/92447982065?pwd=RkhaYkM5VTZPZ3pYSHpt
 UXlRSkppQT09
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