Self-structuring of lamellar bridged silsesquioxanes with long side spacers.

Diurea cross-linked bridged silsesquioxanes (BSs) C(10)C(n)C(10) derived from organosilane precursors, including decylene chains as side spacers and alkylene chains with variable length as central spacers (EtO)(3)Si-(CH(2))(10)-Y-(CH(2))(n)-Y-(CH(2))(10)-Si(OEt)(3) (n = 7, 9-12; Y = urea group and Et = ethyl), have been synthesized through the combination of self-directed assembly and an acid-catalyzed sol-gel route involving the addition of dimethylsulfoxide (DMSO) and a large excess of water. This new family of hybrids has enabled us to conclude that the length of the side spacers plays a unique role in the structuring of alkylene-based BSs, although their morphology remains unaffected. All the samples adopt a lamellar structure.

Optical properties of lanthanide-doped lamellar nanohybrids.

In this article a detailed study of the optical properties of lanthanide doped lamellar nanohybrids synthesized by the "benzyl alcohol route" is presented. The synthetic approach results in the formation of a highly ordered lamellar nanocomposite consisting of yttrium or gadolinium oxide crystalline layers with a confined thickness of about 0.6 nm, separated from each other by organic layers of intercalated benzoate molecules.