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Controlled Construction of Metal–Organic Frameworks: Hydrothermal Synthesis, X‐ray Structure, and Heterogeneous Catalytic Study
Author(s) -
Sen Rupam,
Saha Debraj,
Koner Subratanath
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201102953
Subject(s) - metal organic framework , carboxylate , catalysis , chemistry , hydrothermal circulation , ligand (biochemistry) , acetone , adsorption , inorganic chemistry , aldol condensation , chemical engineering , organic chemistry , biochemistry , receptor , engineering
The role of pH in the formation of metal–organic frameworks (MOFs) has been studied for a series of magnesium‐based carboxylate framework systems. Our investigations have revealed the formation of five different zero‐dimensional (0D) to three‐dimensional (3D) ordered frameworks from the same reaction mixture, merely by varying the pH of the medium. The compounds were synthesized by the hydrothermal method and characterized by single‐crystal X‐ray diffraction. Increase of the pH of the medium led to abstraction of the imine hydrogen from the ligand and a concomitant increase in the OH − ion concentration in the solution, facilitating the construction of higher dimensional framework compounds. A stepwise increase in pH resulted in a stepwise increase in the dimensionality of the network, ultimately leading to the formation of a 3D porous solid. A gas adsorption study of the 3D framework compound confirmed its microporosity with a BET surface area of approximately 450 m 2 g −1 . Notably, the 3D framework compound catalyzes aldol condensation reactions of various aromatic aldehydes with acetone under heterogeneous conditions.