Synthesis, Structure, and Thermal Stability of a Mesoporous Titanium(III) Amine-Containing MOF

Timothy Steenhaut; Séraphin Lacour; Gabriella Barozzino-Consiglio; Koen Robeyns; Robin Crits; Sophie Hermans; Yaroslav Filinchuk

doi:10.1021/acs.inorgchem.2c00825

Synthesis, Structure, and Thermal Stability of a Mesoporous Titanium(III) Amine-Containing MOF

Inorg Chem. 2022 Jul 25;61(29):11084-11094. doi: 10.1021/acs.inorgchem.2c00825. Epub 2022 Jul 11.

Authors

Timothy Steenhaut¹, Séraphin Lacour¹, Gabriella Barozzino-Consiglio¹, Koen Robeyns¹, Robin Crits¹, Sophie Hermans¹, Yaroslav Filinchuk¹

Affiliation

¹ Université catholique de Louvain, MOST, Place Louis Pasteur 1, 1348 Louvain-la-Neuve, Belgium.

Abstract

The first mesoporous bimetallic Ti^III/Al metal-organic framework (MOF) containing amine functionalities on its linkers has been selectively obtained by converting the cheap commercially available (TiCl₃)₃AlCl₃ into Ti_3-xAl_xCl₃(THF)₃ and reacting this complex with 2-aminoterephthalic acid in dimethylformamide (DMF) under soft solvothermal conditions. This compound is structurally related to the previously described NH₂-MIL-101(M) (M = Cr, Al, and Fe) MOFs. Thermal gravimetric analyses and in situ powder X-ray diffraction (PXRD) measurements demonstrated that this highly air-sensitive Ti^III-containing MOF is structurally stable up to 200 °C. Nuclear magnetic resonance (NMR) spectroscopy, elemental analysis, and inductively coupled plasma (ICP) revealed that NH₂-MIL-101(Ti^III) contains trinuclear Ti₃(μ₃-O)Cl(DMF)₂(RCOO)₆ clusters with strongly bound DMF molecules and a small amount of aluminum. Sorption experiments revealed a higher affinity of this MOF for hydrogen compared to the previously described monometallic unfunctionalized MIL-101(Ti^III) MOF.