Sulphur(IV) compounds as ligands. XX. Adduct formation and ring opening of thiirane-1-oxide with organotin halides. Crystal structure of

Article abstract of DOI:10.1016/0022-328X(94)80033-2

The organotin halides RnSnX4-n (R=Ph, 4-MeC6H4, 4-FC6H4; X=Cl, Br; n=0, 1, 2, 3) and Me2SnCl2 form adducts with thiirane-1-oxide.In general, for n=0, 1, 2 these have a 1:2 stoichiometry and are octahedral, as shown by a single-crystal structural study of <(4-FC6H4)2SnCl2(C2H4SO)2> (4c).In 4c the aryl groups are trans to each other and the chloride and sulphoxide ligands mutually cis.The S-O bond is 0.04 Angstroem longer than that in uncoordinated thiirane-1-oxide, whereas the bonds within the three-membered ring are shortened by a similar amount.Depending on the reaction conditions, 1:1 adducts (R=4-MeC6H4, X=Cl, Br; R=Me, t-Bu, X=Cl) can also be isolated, while triorganotin halides form only 1:1 complexes.Analogous dimethylsulphoxide (DMSO) adducts have been synthesized for comparison.On the basis of vibrational spectroscopic data it can be concluded that thiirane-1-oxide is a weaker base than DMSO.This is supported by an NMR study of the formation of the 1:1 adduct between Me2SnCl2 and thiirane-1-oxide (9), which gave the following thermodynamic data: K_eq=8.6 M^-1, ΔH^R = -20.4 kJ mol^-1, ΔS^R = -50 J mol^-1 K^-1.Decomposition of the thiirane-1-oxide adducts at room temperature gives the thiosulphinic acid esters XC2H4S(O)SC2H4X (X=Cl; 18a, Br: 18b) in high yields.Key words: Tin; Sulfur; Sulfoxide