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Mishra MK, Kelley SP, Dilip M, Vaid TP, Cordes DB, Griffin ST, Rogers RD. Crystallographic Insights into the Behavior of Highly Acidic Metal Cations in Ionic Liquids from Reactions of Titanium Tetrachloride with [1-Butyl-3-Methylimidazolium][X] Ionic Liquids (X = Chloride, Bromide, Tetrafluoroborate). Inorg Chem 2019; 58:1764-1773. [PMID: 30640462 DOI: 10.1021/acs.inorgchem.8b00524] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Highly charged metal ions are difficult to investigate in weakly coordinating ionic liquids (ILs) because of the insolubility of their solid forms, but the molecular liquid TiCl4 offers a way to react tetravalent metal ions in an IL. Reactions of TiCl4 with 1-butyl-3-methylimidazolium ([C4mim]+)-based ILs containing chloride or bromide lead to mixtures of highly metastable amorphous solids and small amounts of crystalline chlorotitanate salts including [C4mim]2[TiCl6] and two polymorphs of [C4mim]2[Ti2Cl10] in a manner not well correlated with stoichiometry or anion identity. The reaction of TiCl4 with [C4mim][BF4] yields crystals of the mixed fluoro-chloro complex [C4mim]2[Ti4F6Cl12], indicating spontaneous reaction of the IL ions to generate HF in situ. These unusual behaviors are explained in terms of the exceptionally high acidity of Ti4+ and the unusual behavior of TiCl4 among metal halides as a nonpolar molecular compound.
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Affiliation(s)
- Manish Kumar Mishra
- Department of Chemistry , The University of Alabama , Tuscaloosa , Alabama 35487 , United States
| | - Steven P Kelley
- Department of Chemistry , The University of Alabama , Tuscaloosa , Alabama 35487 , United States
| | - Meghna Dilip
- Department of Chemistry , The University of Alabama , Tuscaloosa , Alabama 35487 , United States
| | - Thomas P Vaid
- Department of Chemistry , The University of Alabama , Tuscaloosa , Alabama 35487 , United States
| | - David B Cordes
- Department of Chemistry , The University of Alabama , Tuscaloosa , Alabama 35487 , United States
| | - Scott T Griffin
- Department of Chemistry , The University of Alabama , Tuscaloosa , Alabama 35487 , United States
| | - Robin D Rogers
- Department of Chemistry , The University of Alabama , Tuscaloosa , Alabama 35487 , United States.,525 Solutions, Inc. , P.O. Box 2206, Tuscaloosa , Alabama 35403 , United States
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