New layered inorganic-organic nanocomposites containing n-propylmercapto copper phyllosilicates

Magnesium and copper phyllosilicates, SILMSH (M = Mg, Cu), were synthesized by a sol-gel process from the reaction of these metallic cations and merca ptotrialkoxysilane in aqueous basic solution at 298 K. The inorganic-organi c hybrids formed were characterized by elemental analysis, giving 4.88 and 3.68 mmol g(-1) of organic groups, with larger thermal stability for the ma gnesium compound and surface areas of 46.9 +/- 1.8 and 107.0 +/- 3.0 m(2) g (-1) for magnesium and copper hybrids, respectively. X-Ray diffraction patt erns gave basal peaks associated with an interlayer distance of 1300 pm for SILMgSH due to the presence of the organic radical chain in the structure. However, for the copper hybrid an interplanar distance of 695 pm was obtai ned. The terminal S-H groups on organic chains in the structure were confir med by infrared data, showing a stretching band at 2556 cm(-1) for the magn esium hybrid, while this same band was absent in copper phyllosilicate. Si- 29 NMR showed the presence of silicon species: R-Si*-(OSi)(3), R-Si*-(OSi)( 2)-OH and R-Si*-(OSi)-(OH)(2) in the inorganic-organic backbone structure. The first species demonstrated that better polymerization occurred in the S ILMgSH hybrid. The amount of copper adsorbed on the magnesium phyllosilicat e was 5.93 mmol g(-1). The interaction of this cation in the SILMgSH matrix can be related to two processes: rearrangement of inorganic layers around copper cations and formation of interlayer complexes with S-H groups. The n anocomposite containing adsorbed copper has a similar structure to the SILC uSH hybrid, suggesting a new route for these copper compounds. A simple low -temperature procedure was employed to synthesize these reproducible SILMgS H/Cu and SILCuSH hybrids, which are 1 : 1 phyllosilicates.