Variable‐temperature 13C CP/MAS study of (Me3Sn)2CO3

Solid (Me3Sn)2CO3, 1, forms polymeric zig‐zag chains were bidentate magnified image units (containing a tetrahedral Me3Sn group) connect trigonal‐bipyramidal Me3SnO2 units which form the polymeric backbone. Both the tetrahedral and the trigonal‐bipyramidal Me3Sn moiety in solid 1 undergo 2π/3 reorientation around their respective SnO bonds at ambient temperature. Although 13C cross‐polarization magic angle spinning (CP/MAS) spectra of 1 are strongly temperature dependent in the temperature range 160–383 K, neither lineshape analysis of these exchange‐broadened 13C spectra nor 13C 2D exchange spectroscopy allows the extraction of meaningful kinetic data for solid 1. Owing to severe overlap problems in the various 13C CP/MAS spectra and because of the apparent vastly different 2π/3 jump rates for the two different Me3Sn units in solid 1, only combined information from variable‐temperature/variable‐r.f. irradiation strength 13C CP/MAS experiments in conjunction with consideration of geometric information from single‐crystal x‐ray diffraction yields an estimate of the respective activation energies for the 2π/3 jump processes of the trigonal‐bipyramidal Me3Sn(1) unit (Ea = 22.1 ± 2.4 kJ mol−1) and of the tetrahedral Me3Sn(2) unit (Ea ≈︁ 50 kJ mol−1) in solid 1.