The Unexpected Motional Isotropy of the Tin Atom in a Tricoordinate Stannylium Cation

Abstract

The dynamics of the metal atom in the recently isolated tricoordinate tin complex tris(2,4,6-triisopropylphenyl)stannylium tetrakis(pentafluorophenyl)borate was examined by temperature-dependent (119)Sn Mössbauer spectroscopy over the temperature range 90 K < T < 170 K. Contrary to expectation, the metal atom motion in this temperature range is isotropic within experimental error of the Mössbauer data, and is only moderately anisotropic, even at 293 K, as evidenced by single crystal X-ray diffraction data. The hyperfine parameters at 90 K are completely consistent with trigonal coordination involving sp(2) hybridization of the 5s5p bonding orbitals of tin.

In search for a pentacoordinated monoorgano stannyl cation

“…In addition, they have received increasing interest in applied research as catalysts for the polymerization of alkenes [3,4], acylation of alcohols [5,6], and the Diels-Alder cycloaddition [7,8]. Several stannylium ions A were isolated in the solid state [9][10][11][12][13]. In all cases these were triorgano derivatives stabilized by a combination of bulky substituents and the weakly coordinating anion (WCA [14]) [B(C 6 F 5 ) 4 ] -.…”