Synthesis and characterization of a stable non-cyclic bis(amino)arsenium cation

Abstract

The reaction of Li[Mes*NH] (1, Mes* = 2,4,6-tri-tert-butylphenyl) with aminoarsane Mes*N(H)AsCl2 (2, Mes* = 2,4,6-t-Bu3C6H2) at −80 °C resulted in the formation of bisamino(chloro)arsane (Mes*NH)2AsCl (3Cl) by elimination of LiCl. 3Cl reacted with the Lewis acids such as AlCl3, GaCl3, and Ag[X] (X = AsF6−, OTf−, BF4−; OTf = trifluoromethanesulfonate = OSO2CF3−) upon chloride ion abstraction to give salts bearing the cation [(Mes*NH)2As]+ (3[X]; X = AsF6−, OTf−, BF4−, ECl4; E = Al, Ga). 3+ represents the first NH-functionalized acyclic bis(amino)arsenium cation. The formation of the salts bearing 3+ could also be observed in the reaction of cyclo-1,3-diarsa-2,4-diazane [ClAs(μ-NMes*)]2 (4) with Lewis acids (AlCl3, GaCl3) in the presence of proton sources in solution. All presented salts 3[X] were stable at room temperature and fully characterized.