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Influence of a Confined Methanol Solvent on the Reactivity of Active Sites in UiO‐66
Author(s) -
Caratelli Chiara,
Hajek Julianna,
Rogge Sven M. J.,
Vandenbrande Steven,
Meijer Evert Jan,
Waroquier Michel,
Van Speybroeck Veronique
Publication year - 2018
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201701109
Subject(s) - solvent , methanol , chemistry , molecular dynamics , hydrogen bond , deprotonation , active site , adsorption , reactivity (psychology) , solvent effects , oxide , molecule , computational chemistry , chemical physics , photochemistry , catalysis , organic chemistry , ion , medicine , alternative medicine , pathology
UiO‐66, composed of Zr‐oxide bricks and terephthalate linkers, is currently one of the most studied metal–organic frameworks due to its exceptional stability. Defects can be introduced in the structure, creating undercoordinated Zr atoms which are Lewis acid sites. Here, additional Brønsted sites can be generated by coordinated protic species from the solvent. In this Article, a multilevel modeling approach was applied to unravel the effect of a confined methanol solvent on the active sites in UiO‐66. First, active sites were explored with static periodic density functional theory calculations to investigate adsorption of water and methanol. Solvent was then introduced in the pores with grand canonical Monte Carlo simulations, followed by a series of molecular dynamics simulations at operating conditions. A hydrogen‐bonded network of methanol molecules is formed, allowing the protons to shuttle between solvent methanol, adsorbed water, and the inorganic brick. Upon deprotonation of an active site, the methanol solvent aids the transfer of protons and stabilizes charged configurations via hydrogen bonding, which could be crucial in stabilizing reactive intermediates. The multilevel modeling approach adopted here sheds light on the important role of a confined solvent on the active sites in the UiO‐66 material, introducing dynamic acidity in the system at finite temperatures by which protons may be easily shuttled from various positions at the active sites.