Tin(IV) and organotin(IV) complexes containing mono or bidentate N-donor ligands-I. 1-benzylimidazole derivatives

Article abstract of DOI:10.1016/0277-5387(95)00384-3

The interaction between 1-benzylimidazole, L, and several tin(IV) and organotin(IV) acceptors in diethyl ether or THF, gave 1 : 1 [(L)R₃SnCl] (R = Me or Ph), 2 : 1 [(L)₂R_nSnX_4-n] (R = Me, n = 2, X = Cl or Br ; R - Et, Bu or Ph, n = 2, X = Cl, Br or I; R = cy, n = 2, X = Br or I; R = Me, Ph or Bu, n = 0 or 1, X = Cl; R = Me, n = 0 or 1, X = I; n = 0, X = Br), [(L)₂Ph₂SnBrCl] and 4 : 1 [(L)₄(CH₃)₂Sn]I₂, adducts which are air- and thermally stable solids. The compounds have been characterized in the solid state and in solution by analyses, spectral (IR and ¹H, ¹³C and ¹¹⁹Sn NMR) data and conductivity measurements. The molecular weight determinations and the NMR data indicate that the triorganotin complexes generally dissociate in chloroform and in acetone solution, whereas only a slight dissociation of the di-, tri- and tetrahalidetin(IV) adducts in CHCl₃ is found : these [(L)₂R_nSnX_4-n] complexes most likely retain the six-coordinate configuration. They are not fluxional when n = 0 or 1. The ¹¹⁹Sn NMR chemical shift is a function of the number and type of substituents directly linked to the tin atom. In the diorganotin derivatives, the coupling constants ²J_119Sn-1H and ¹J_119Sn-13C were used to establish the stereochemistry of the tin atom by applying the Lockhart and Holecek equations, which allow the magnitude of the C - Sn - C bond angles to be derived.