Structural Features in Metal–Organic Nanotube Crystals That Influence Stability and Solvent Uptake
datasetposted on 05.08.2015, 00:00 by Ashini S. Jayasinghe, Daniel K. Unruh, Andrew Kral, Anna Libo, Tori Z. Forbes
Porous hybrid materials such as metal–organic nanotubes are of interest due to synthetic tunability, possibility for 1-D flow, and confinement of solvent molecules. In the current study, the stability and solvent selectivity of two hybrid materials with nanotubular arrays, (pip)0.5[(UO2)(HIDA)(H2IDA)]·2H2O (UIDA; IDA = iminodiacetate) and [(UO2)(PDC)(H2O)] (UPDC; PDC = pyridine dicarboxylate) were analyzed using X-ray diffraction, gas chromatography/mass spectrometry, thermogravimetric analysis, and infrared spectroscopy. The fine details of the structural characterization, such as the presence of solvent molecules, were found to be important to the overall properties of the materials as evidenced by the increased stability of the UIDA compound when formed from a solvent mixture containing acetone. Careful analysis of the UPDC compound indicated that the ligated solvent molecule can be exchanged, which may impact the hydration state of the material. Overall, the UIDA compound displays complete selectivity to water, but the UPDC compound adsorbs THF, methanol, ethanol, and cyclohexane.