Synthesis, Properties, and Application of Tetrakis(pentafluoroethyl)gallate, [Ga(C2 F5 )4 ].

Weakly coordinating anions (WCAs) are important for academic reasons as well as for technical applications. Tetrakis(pentafluoroethyl)gallate, [Ga(C2 F5 )4 ]- , a new WCA, is accessible by treatment of [GaCl3 (dmap)] (dmap=4-dimethylaminopyridine) with LiC2 F5 . The anion [Ga(C2 F5 )4 ]- proved to be reluctant towards deterioration by aqueous hydrochloric acid or lithium hydroxide. Various salts of [Ga(C2 F5 )4 ]- were synthesized with cations such as [PPh4 ]+ , [CPh3 ]+ , [(O2 H5 )2 (OH2 )2 ]2+ , and [Li(dec)2 ]+ (dec=diethyl carbonate). Thermolysis of [(O2 H5 )2 (OH2 )2 ][Ga(C2 F5 )4 ]2 gives rise to a dihydrate of tris(pentafluoroethyl)gallane, [Ga(C2 F5 )3 (OH2 )2 ]. All products were characterized by NMR and IR spectroscopy, mass spectrometry, X-ray diffraction, and elemental analysis. Furthermore, an outlook for the application of [Li(dec)2 ][Ga(C2 F5 )4 ] as a conducting salt in lithium-ion batteries is presented.