Synthesis, Polymorphism and Thermal Decomposition Process of (n-C4H9)4NRE(BH4)4 for RE = Ho, Tm and Yb.

Wojciech Wegner,Tomasz Jaroń

doi:10.3390/ma14061329

Abstract

In total, three novel organic derivatives of lanthanide borohydrides, n-But4NRE(BH4)4 (TBAREB), RE = Ho, Tm, Yb, have been prepared utilizing mechanochemical synthesis and purified via solvent extraction. Studies by single crystal and powder X-ray diffraction (SC-XRD and PXRD) revealed that they crystalize in two polymorphic forms, α- and β-TBAREB, adopting monoclinic (P21/c) and orthorhombic (Pnna) unit cells, previously found in TBAYB and TBAScB, respectively. Thermal decomposition of these compounds has been investigated using thermogravimetric analysis and differential scanning calorimetry (TGA/DSC) measurements, along with the analysis of the gaseous products with mass spectrometry (MS) and with analysis of the solid decomposition products with PXRD. TBAHoB and TBAYbB melt around 75 °C, which renders them new ionic liquids with relatively low melting points among borohydrides.

Highlights

IntroductionStudies by single crystal and powder X-ray diffraction (SC-XRD and Powder X-ray Diffraction (PXRD))
(TBAREB), RE = Ho, Tm, Yb, have been prepared utilizing mechanochemical synthesis and purified via solvent extraction
The samples were recrystallized and single crystals were investigated by Single-Crystal X-ray Diffraction (SC-XRD); the crystal structures have been discussed in the Section 3.2

Summary

Introduction

Studies by single crystal and powder X-ray diffraction (SC-XRD and PXRD). Revealed that they crystalize in two polymorphic forms, α- and β-TBAREB, adopting monoclinic (P21 /c) and orthorhombic (Pnna) unit cells, previously found in TBAYB and TBAScB, respectively. Thermal decomposition of these compounds has been investigated using thermogravimetric analysis and differential scanning calorimetry (TGA/DSC) measurements, along with the analysis of the gaseous products with mass spectrometry (MS) and with analysis of the solid decomposition products with PXRD. (n-C4 H9 ) NRE(BH4 ) for RE = Ho, Metal borohydrides constitute a continuously growing family of chemical compounds. Most of studies focus on examining of the process of hydrogen release, several reports indicate at least some degree of reversibility of such systems, which is crucial for their application, e.g., [10]

Methods

Results

Conclusion