Preparation and characterization of Tl(1,2-C₂H₄Cl₂)B(OTeF₅)₄: a metal complex of a least coordinating solvent and a least coordinating anion

Abstract

Addition of B(OTeF 5 ) 3 to TIOTeF 5 in the weakly coordinating solvents dichloromethane, 1,2-dichloroethane, and 1,1,2-trichlorotrifluoroethane produces solutions of M(solv) x + B(OTeF 5 ) 4 − . When the solvent was 1,2-dichloroethane, the crystalline compound Tl(1,2-C 2 H 4 Cl 2 )B(OTeF 5 ) 4 was isolated and studied by X-ray crystallography: triclinic, space group [Formula: see text], a = 9.221 (4), b = 11.396(5), c = 12.538 (4) Å, α = 110.75 (3)°, β = 101.72(3)°, γ = 99.74 (3)°, Z = 2, T = −116 °C. The Tl(1,2-C 2 H 4 Cl 2 ) + cation contains a five-membered chelate ring with Tl—Cl distances of 3.138 (4) and 3.179 (3) Å. The metal ion is weakly bonded to four B(OTeF 5 ) 4 − counterions, with nine Tl—F interactions that range from 2.950 (5) to 3.981 (8) Å. When the solvent is dichloromethane or 1,1,2-trichlorotrifluoroethane, only the unsolvated solid salt TlB(OTeF 5 ) 4 can be isolated by crystallization. This salt is thermally unstable, slowly forming TlOTeF 5 and volatile B(OTeF 5 ) 3 . Keywords: noncoordinating anion, noncoordinating solvent, metal ion solvation.