Investigations of tin(II) halide aqueous solutions and solvent extracts by 119Sn nuclear magnetic resonance spectroscopy: characterisation of the trihalogenostannate(II) anions [SnX3]–, [SnX2Y]–, and [SnX(Y)Z]–(X, Y, or Z = Cl, Br, or I)

Abstract

The ¹¹⁹Sn chemical shifts of all ten trihalogenostannate(II) anions [SnCl_xBr_yI_z]^–(x+y+z= 3) are observed in diethyl ether extracts of tin(II) mixed-halide systems measured at –60°C. The tin(II) nuclear shielding order I < Br < Cl is the opposite of that found in tin(iv) halide systems. At room temperature, the tin resonance signals of tin(II) complexes in aqueous HCl, HBr, and Hl solutions, or their solvent extracts, are single peaks whose positions depend on the composition of the phase, showing that several species are in rapid equilibrium. The complex acids H [SnX₃] exhibit ¹¹⁹Sn chemical shifts of δ=–40 (X = Cl), +135 (X = Br), and +350 (X = l) p.p.m. in ether extracts at room temperature.