Skew-trapezoidal bipyramidal diorganotin(IV) bischelates. Crystal structure of dimethylbis(2-pyridinethiolato-N-oxide)tin(IV)

Dimethylbis(2-pyridinethiolato-N-oxide)tin(IV), Me₂Sn(2-SPyO)₂, crystallizes in space group P2₁/c with a 9.877(3), b 11.980(4), c 13.577(3) Å, β 109.1(2)° and Z = 4. The structure was refined to R_F = 0.036 for 2263 Mo-K_α observed reflections. The coordination geometry at tin is a skew-trapezoidal bipyramid, with the oxygen [SnO 2.356(3), 2.410(4) Å] and sulfur [SnS 2.536(1), 2.566(1) Å] atoms of the chelating groups occupying the trapezoidal plane and the methyl groups [SnC 2.106(6), 2.128(7) Å] occupying the apical positions. The methyl-tin-methyl skeleton is bent [CSnC 138.9(2)°]. The SSnS angle is 77.8(1)°, but the OSnO angle is opened to 136.7(1)° to accommodate the intruding methyl groups. The carbontincarbon angles predicted from quadrupole splitting (^119mSn Mössbauer) and one-bond ¹¹⁹Sn¹³C coupling constant (solution ¹³C NMR) data agree closely with the experimental value.