Fluoride Ion-Encapsulated Germoxane Cages Modified with Organosiloxane Chains as Anionic Components of Ionic Liquids

Taiki Hayashi, Nanako Murase, Naoto Sato, Koki Fujino, Natsuhiko Sugimura, Hiroaki Wada, Kazuyuki Kuroda, Atsushi Shimojima*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Herein, we report the preparation of a new class of inorganic-organic hybrid ionic liquids by modification of a double-four-ring (D4R)-type germoxane (Ge-O-Ge) compound, containing a fluoride ion inside and a tetraethylammonium cation outside, with organosiloxane chains. D4R-type inorganic compounds are attractive as anionic components of ionic liquids because of their ability to encapsulate a fluoride ion inside the cage and allow various functional groups to be linked at the cage corners. The crystalline D4R-type germoxanes with corner Ge-OH groups were successfully converted to clear liquids by modification with dimethylvinylsilyl groups, followed by hydrosilylation with flexible oligosiloxanes (HSi(OSiMe3)nMe3-n, n = 1-3). The resulting products showed liquid behaviors below 0 °C and were stable against thermal decomposition up to ∼200 °C. Additionally, they had high affinities for both hydrophilic and hydrophobic substances, attributable to the organosiloxane chains surrounding the ionic cage. Furthermore, the differences between the D4R-type germoxane and D4R-type siloxane were investigated using density functional theory calculations. The symmetry of the optimized structure and its electrostatic nature indicated that D4R-type germoxane is advantageous for the creation of ionic liquids.

Original languageEnglish
Pages (from-to)1454-1463
Number of pages10
Issue number11
Publication statusPublished - 2022 Jun 13

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry


Dive into the research topics of 'Fluoride Ion-Encapsulated Germoxane Cages Modified with Organosiloxane Chains as Anionic Components of Ionic Liquids'. Together they form a unique fingerprint.

Cite this