Self-assembly of layered organosilicas based on weak intermolecular interactions

New layered hybrid organic-inorganic materials were obtained directly by hydrolysis and polycondensation of monosilylated precursors of type (EtO)(3)Si(CH2)(3)NH(C=O)NHCnH2n-1 (n = 3, 8, 12 and 16) These precursors were easily prepared by reaction between commercially available triethoxysilylpropylisocyanate and primary aminoalkanes The obtained materials were characterized by combining elemental analysis. X-ray powder diffraction, C-13, Si-29 NMR and FT-IR spectroscopes They were found to be well condensed, and stable in water We showed that their formation results from a cooperative effect between hydrogen bonding interactions originating from ureido groups and hydrophobic interactions between the long alkyl chains There is no formation of material when n = 2. or from (EtO)(3)StC(n)H(2n+1) when n = 18, thus proving that both types of weak intermolecular interactions are required The chelating property of these materials towards europium(III) ions was tested