Journal article
Energetics of Formation and Hydration of a Porous Metal Organic Nanotube
Chemistry of materials, Vol.26(17), pp.5105-5112
09/09/2014
DOI: 10.1021/cm5024053
Abstract
Hybrid materials, such as metal organic nanotubes (MON), are of interest because of their chemical tunability and permanent porosity. While an increasing number of compounds is being reported, very little is known about their thermodynamic stability. Herein, the energetics of a MON, (C4H12N2)0.5[(UO2)(Hida)(H2ida)]·2H2O (UMON, C10H21N3UO12) (ida = iminodiacetate), that possesses unique water exchange and uptake has been investigated by acid solution calorimetry, thermal analysis, and water adsorption calorimetry. The enthalpy of formation of UMON, C10H21N3UO12 (ΔH f,rxn), from the dense components (uranium oxide (UO3), piperazine (C4H10N2), and iminodiacetic acid (C4H7NO4) was −55.3 ± 0.9 kJ/mol, which was similar to values for other metal organic framework materials. The dehydration enthalpy to form an anhydrous UMON and gaseous H2O at 37 °C from thermogravimetric analysis (TGA)/differential scanning calorimetry (DSC) experiments was 57.8 ± 1.9 kJ/mol of water. This value is somewhat higher than the vaporization enthalpy of water (44 kJ/mol) and suggests modest bonding interactions of H2O with the inner walls of the nanotubes. Water adsorption calorimetry of (C4H12N2)0.5[(UO2)(Hida)(H2ida)]·2H2O indicated that the water molecules are confined inside the UMON material in two thermally distinct positions. The ice-like arrangement of the confined water molecules inside the nanotube impacts the energetics of the material and adds to the stabilization of the structure.
Details
- Title: Subtitle
- Energetics of Formation and Hydration of a Porous Metal Organic Nanotube
- Creators
- Sulata K Sahu - University of California, DavisDaniel K Unruh - University of IowaTori Z Forbes - University of IowaAlexandra Navrotsky - University of California, Davis
- Resource Type
- Journal article
- Publication Details
- Chemistry of materials, Vol.26(17), pp.5105-5112
- Publisher
- American Chemical Society
- DOI
- 10.1021/cm5024053
- ISSN
- 0897-4756
- eISSN
- 1520-5002
- Grant note
- DOI: 10.13039/100000078, name: Division of Materials Research, award: DMR1252831; DOI: 10.13039/100006151, name: Basic Energy Sciences, award: DESC0001089
- Language
- English
- Date published
- 09/09/2014
- Academic Unit
- Chemistry; Civil and Environmental Engineering; Core Research Facilities
- Record Identifier
- 9983985827302771
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