ChemInform Abstract: The Influence of Intramolecular Coordination and Ring Strain on the Polymerization Potential of Cyclic Stannasiloxanes

Abstract

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ON THE REACTION OF DIORGANODIHYDROXYSILANES WITH (t-Bu2SnO)3. SYNTHESIS AND CHARACTERISATION OF A NOVEL STANNASILOXANE COMPLEX AND ITS DISSOCIATION IN SOLUTION

“…The formation of 1 in the equilibrium according to eq (2) results from immediate self-condensation of f-Bu2Sn(OH) 2 (3), which is supposed to be the initial product of the dissociation of 2. When generated under water-free conditions by reaction of if-Bu 2 SnOSiPh 2 SnO)2 [13] with 1 (eq 4) 2a displays a 119 Sn resonance at -98.6 ppm (2j( 119 Sn-0-" 7 Sn) 298 Hz) with a line width W 1/2 = 5 Hz. Figure 3) comparable with [f-Bu2Sn(OH)X]2 (X = F, CI, Br) [8], This view is further supported by a careful sideband analysis of the 119 Sn CP MAS NMR spectrum of 3 ( Figure 4) according to the method of Herzfeld and Berger [9] using the convention of Haeberlen [10], The parameters obtained (anisotropy Δσ = -598.6 ppm, asymmetry η = 0.69) are in favour of the proposed structure (Figure 3) with the f-butyl groups in equatorial positions.…”