3.2.1. Trimethyltin(IV) butyrate (BT1)

Physical state: white solid; yield: 82%. m.p. 124–126 °C. Formula Weight, FW = 250.91. Anal. Calc. for C₇H₁₆O₂Sn: C 33.51; H 6.43; Sn 47.31%; Found: C 33.74; H 6.47; Sn 47.27%. IR (KBr, cm⁻¹): 1565 ν_as (COO⁻), 1345 ν_s (COO⁻), 545 (Sn–C), 488 (Sn–O), 220 Δν. ¹H NMR (CDCl₃, ppm): 2.24 (t, 2H, CH₂(2) ligand); 1.60 (m, 2H, CH₂(3) ligand); 0.90 (t, 3H, CH₃(4) ligand); 0.51 (s, 9H, CH₃-α; ²J(¹¹⁹Sn–¹H) = 58 Hz). ¹³C NMR (CDCl₃, ppm): 181.23 (COOH); 39.57 (C2 ligand); 21.53 (C3 ligand); 16.58 (C4 ligand); 0.09 (CH₃-α, ¹J(¹¹⁹Sn–¹³C), 400 Hz). ¹¹⁹Sn NMR (ppm): 124.02. ESI-MS: m/z 416 [BT1+SnMe₃]⁺; m/z 274 [BT1+Na]⁺; m/z 236 [BT1-CH₃]⁺; m/z 165 [SnMe₃]⁺. MS/MS of m/z 237: m/z 206 [BT1-3CH₃]⁺; m/z 165 [SnMe₃]⁺; m/z 150 [SnMe₂]⁺. MS/MS of m/z 237: m/z 150 [SnMe₂]⁺.