Metal-organic nanotubes (MONs) are a less studied class of hybrid materials and possess interesting properties due to the presence of 1D nanoscale pores. The unique shape and pore dimensionality suggests that MONs may be suitable candidates for advanced membrane technologies. A U(VI) based MON was synthesized and single-crystal X-ray diffraction indicated that water molecules are arranged in an ice-array within interior channel.<sup>1</sup> Additional investigations indicated that the MON was selective to water and underwent reversible dehydration at 40 °C. In the current study, the rate of gaseous uptake was measured using a range of relative humidity conditions. A gas adsorption apparatus was developed where and water vapor was passed at a constant flow rate into a chamber contained dehydrated MONs and the rates of uptake were determined by determining the mass of water added at specific time intervals. Selectivity of the MON to other vapors was explored by exposing dehydrated crystals to vapors of different solvents with varying sizes, shapes and polarities separately. Solvent uptake was monitored by thermogravimetric analyses (TGA) and the identity of the absorbed species was determined by Fourier Transformation Infrared (FTIR) Spectroscopy of the evolved gas. Our results indicate that the water uptake rate depends on the humidity of the environment and these rates are higher than values reported in the literature for similar materials. The MON also does not show uptake of any other solvent vapor, confirming that it is selective to water both in the liquid and gaseous phases.

Exploring water selective properties and uptake rates of a uranium metal-organic nanotube

253rd National Meeting (2017)

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