Synthesis and Reactivity of Tris(pentafluoroethyl)gallium Compounds. Issue 30 (17th June 2019) - Niemann, Mark
Abstract : The reaction of [GaCl3 (OEt2 ) n ] with LiC2 F5 surprisingly leads to the formation of the anion [Ga(C2 F5 )3 Cl] – . The obtained lithium and tetraphenylphosphonium salts are useful starting materials for new pentafluoroethylgallium compounds. [PPh4 ][Ga(C2 F5 )3 Cl] was conveniently transformed into [PPh4 ][Ga(C2 F5 )3 X] (X = F, Br, I) with HF, NaBr, and NaI. Treatment of [Li(OEt2 ) n ][Ga(C2 F5 )3 Cl] with aqueous hydrogen chloride gives rise to the tris(pentafluoroethyl)gallane adduct [Ga(C2 F5 )3 {(OH2 )(OEt2 )}]. Thermolysis of [Li(OEt2 ) n ][Ga(C2 F5 )3 Cl] affords another tris(pentafluoroethyl)gallane adduct, [Ga(C2 F5 )3 (OEt2 )], which can be converted into [Ga(C2 F5 )3 (dmap)] (dmap = 4‐dimethylaminopyridine). [Ga(C2 F5 )3 (OEt2 )] as well as [Ga(C2 F5 )3 (dmap)] react with [PPh4 ]Cl to [PPh4 ][Ga(C2 F5 )3 Cl] and with HF to [HDMAP][Ga(C2 F5 )3 F]. Both [Ga(C2 F5 )3 (OEt2 )] and [Ga(C2 F5 )3 (dmap)] are precursors for the previously reported weakly coordinating anion [Ga(C2 F5 )4 ] – . Characterizations of the new compounds were carried out by NMR and IR spectroscopy, mass spectrometry, X‐ray diffraction and elemental analyses. Abstract : The reaction of [GaCl3 (OEt2 ) n ] with LiC2 F5 leads to the formation of the anion [Ga(C2 F5 )3 Cl] – . Furthermore, all halogenogallates [Ga(C2 F5 )3 X] – (X = F, Cl, Br, I) are described. [Li(OEt2 ) n ][Ga(C2 F5 )3 Cl] serves as starting material for tris(pentafluoroethyl)gallane adducts [Ga(C2 F5 )3 (D)] (D = OEt2, DMAP), which act as precursors for the weakly coordinating anion [Ga(C2 F5 )4 ] – .