AUTHOR=Filippov Andrei , Munavirov Bulat , Glavatskih Sergei , Shah Faiz Ullah , Antzutkin Oleg N. 

TITLE=Diffusion of Ions in Phosphonium Orthoborate Ionic Liquids Studied by 1H and 11B Pulsed Field Gradient NMR

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 8 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2020.00119

DOI=10.3389/fchem.2020.00119

ISSN=2296-2646

ABSTRACT=Non-halogenated boron based ionic liquids (ILs) composed of phosphonium cations and chelated orthoborate anions have a high hydrolytic stability, a low melting point and exceptional properties in various applications. This study is focussed on ILs with the same type of cation – trihexyltetradecylphosphonium ([P6,6,6,14]+) and two orthoborate anions, such as bis(salicylato)borate ([BScB]-) and bis(oxalato)borate ([BOB]-), and compared with our previous studies on ILs with bis(mandelato)borate ([BMB]-) and a variety of different cations (tetraalkylphosphonium, dialkylpyrrolidinium and dialkylimidazolium). The ion dynamics and phase behavior of these ILs is studied using 1H and 11B pulsed-field-gradient (PFG) NMR technique. PFG NMR is demonstrated to be a useful tool to elucidate the dynamics of ions in this class of phosphonium orthoborate ionic liquids. In particular, applicability of 11B PFG NMR for anions without 1H, such as in [BOB]- and the limitations of this technique to measure self-diffusion of ions in ILs are demonstrated and discussed in detail for the first time.