Tin Nanoparticles in Carbon/Silica Hybrid Materials by the Use of Twin Polymerization

Abstract

Simultaneous twin polymerization was used to synthesize hybrid materials composed of tin oxide, silica, and a phenolic resin starting from a mixture of 2,2′-spirobi[4H-1,3,2-benzodioxasiline] (Si-spiro) with either the tin(IV) alkoxides 2,2′-spirobi[4H-1,3,2-benzodioxastannine] (A), 2,2′-spirobi[6-methyl-4H-1,3,2-benzodioxastannine] (B), and 2,2′-spirobi[6-methoxy-4H-1,3,2-benzodioxastannine] (C) or the novel tin(II) alkoxides tin(II)-2-(oxidomethyl)-4-methoxyphenolate (D) and tin(II)-2-(oxidomethyl)-5-methoxyphenolate (E). In addition, the twin polymerization of the twin monomer Si-spiro in the presence of tin-containing additives, such as Sn(OtBu)₄, Sn(OnBu)₂, Sn(OAc)₄, and Sn(OAc)₂, was investigated for comparison. The as-prepared hybrid materials were characterized using solid-state NMR spectroscopy (¹³C, ²⁹Si, ¹¹⁹Sn) and high-angle annular dark field scanning transmission electron microscopy, and were finally converted under Ar/H₂ atmosphere at 600 °C to tin nanoparticles (10–200 nm) in porous carbon/silica hybrid materials (Sn/C/SiO₂) with BET surface areas up to 352 m² g⁻¹.