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 self -assembly 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 tem-perature 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) angstrom, b = 16.316(2) angstrom, and c = 6.9650(4) angstrom. 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.