Novel 10- and 20- membered tin- and silicon-containing rings: synthesis, complexation behavior and conversion into a lewis acidic polymer

Reaction of the dimethylsilylmethyl-substituted tetraorganotin derivative CH₂[CH₂Sn(Ph₂)CH₂Si(H)Me₂]₂ (1) and CH₂[CH₂Sn(Ph₂)CH₂Si(i-PrO)Me₂]₂ (3), respectively, with mercuric chloride afforded the novel silicon- and tin-containing 10- and 20-membered rings cyclo-CH₂[CH₂Sn(Cl₂)CH₂Si(Me₂)]₂O (4) and cyclo-CH₂[CH₂Sn(Cl₂)CH₂Si(Me₂)OSi(Me₂)CH₂Sn(Cl₂)CH₂]₂CH₂ (5). Both compounds 4 and 5 can be converted into the soluble Lewis acidic polymer poly-[Si(Me₂)CH₂Sn(Cl₂)(CH₂)₃Sn(Cl₂)CH₂Si(Me₂)O] (8). ¹¹⁹Sn NMR studies indicate that 4 acts as a bidentate Lewis acid toward chloride ions, exclusively forming the 1:1 complex [cyclo-CH₂[CH₂Sn(Cl₂)CH₂Si(Me₂)]₂O·Cl]-[(Ph₃P)₂N]⁺ (7). The molecular structures as determined by single-crystal X-ray diffraction analysis of 4 and 7 are reported.