Synthesis and reactions of a stannanethione derived from a kinetically stabilized diarylstannylene

Stannanethione Tbt(Tip)Sn=S (Tbt = 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl; Tip = 2,4,6-triisopropylphenyl), containing a novel tin-sulfur double bond, was synthesized by the reactions of the corresponding kinetically stabilized diarylstannylene Tbt(Tip)Sn: with styrene episulfide or elemental sulfur. An absorption maximum due to the n-pi* transition of the tin-sulfur double bond appeared at 473 nm in hexane. It reacted with thiocumulenes such as carbon disulfide and phenyl isothiocyanate and with styrene oxide and mesitonitrile oxide to give the corresponding cycloadducts. The structure of the [2 + 2] cycloadduct of a stannanethione with carbon disulfide was determined by X-ray structural analysis. In contrast to Tbt(Tip)Sn=S, the less hindered stannanethione Tbt(Mes)Sn=S (Mes = mesityl) dimerized at room temperature to afford the corresponding 1,3,2,4-dithiadistannetane.