Morphology controlled synthesis of yttrium metal–organic frameworks with a tritopic ligand

Metal-Organic Frameworks (MOFs) are extended three-dimensional metal–organic clusters created by the selfassembly of metal ions with organic ligands, whose repeated unit spreads in space very orderly. Yttrium based 3D network structure, have been synthesized using the tritopic organic linker 1,3,5-benzenetricarboxylic acid (H3-BTC) adopting a one-pot, green approach through a fine tuning of the process parameters like temperature and time. The syntheses have been carried out at various temperatures and reaction times, in order to correlate the morphological and structural features to the synthetic conditions. The synthesized Y-BTC samples have been studied in detail through powder X-ray diffraction (PXRD) and FT-IR spectroscopy in order to analyse the 3D structure arrangements. Specifically, the Y-BTC PXRD patterns have been compared with patterns derived from literature data. The Y-BTC sample synthesized at room temperature for 24 h has the same structure of the known Y(BTC)(H2O)6 compound, while the Y-BTC produced at high temperature for 24 h has a new structure, whose cell parameters are a = 14.668(2) Å, b = 16.316(2) Å, and c = 6.9650(4) Å. Field emission scanning electron microscopy (FE-SEM) has allowed to investigate the morphological evolution of the MOF as a function of operative parameters. Additionally, thermal analyses (TGA and DSC) have assessed the thermal stability and structural modifications of the Y-BTC samples.