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A layer-by-layer deposition method is presented for the fabrication of compact c-oriented-MCM-22/silica films on aluminum alloys and porous α-alumina discs. The film fabrication procedure combines deposition of platelike MCM-22 crystals on substrates by covalent attachment under reflux and/or by sonication-assisted covalent attachment (using the methods introduced by Yoon and co-workers and recently reviewed [Acc. Chem. Res. 2007, 40 (1), 29−40]) with evaporation-induced-self-assembly (EISA) of surfactant-templated silica. The composite c-oriented MCM-22/silica films exhibited corrosion resistance barrier properties comparable to commercial chromate conversion coatings. Moreover, they exhibited hydrogen ideal selectivities (e.g., H2/N2 ∼ 7) above those expected by Knudsen diffusion indicating molecular sieving potential.

c-Oriented columnar MFI films made by secondary growth of randomly oriented seed monolayers, deposited using sonication-assisted covalent attachment, exhibit n-hexane/2,2-dimethylbutane separation factor of up to 104, n-/i-butane separation factor of up to 50, and p-/o-xylene separation factor of up to 2. A MFI film from a-oriented seed layer shows lower separation factors for the linear vs. branched isomers but higher separation factor for p-/o-xylene.

The preparation of smooth mesoporous silica layers on rough, porous stainless steel supports and the subsequent synthesis of well-intergrown b-oriented MFI films on these intermediate layers were i...

The effect of drying and ageing conditions on both the degree of polycondensation at silicon and the texture connected with the surface properties (BET, porosity) has been investigated in the case of silica and nanostructured hybrid organic–inorganic solids, obtained by hydrolytic sol–gel performed from a molecular precursor. Various molecular geometries and structural features were investigated using acid or nucleophilic catalysts in MeOH or THF. The aim of this work is first to study the effect of the temperature on the surface properties occurring during the ageing alone which was studied independently of gel formation. The second aim was to consider whether the polycondensation at silicon is influenced by the drying step. The main trend that emerges from these results is the drastic influence of ageing temperature on the texture and porosity of the xerogels. Whereas the level of condensation at silicon is not modified, we observed that higher ageing temperatures favor an increase of the specific surface area and an evolution towards a mesoporosity with narrow pore size distribution, whatever is the level of polycondensation at silicon. In contrast, the drying procedure (transformation of gel into xerogel) induces a significant increase of the level of condensation at silicon (10–14%) when the leaving group of the precursor is OEt, whereas in the case of the OMe group no evolution is observed. The same experimental facts have also been observed in the case of SiO2.

The stereochemistry of the cobalt(II) chloride catalysed opening of cinnamoyl epoxides with N-substituted anilines is controlled by the para substituent of the aromatic ring attached to nitrogen atom. Thus the secondary amine having a para methoxy group cleaves the epoxide to afford the corresponding anti amino alcohol as the major product whereas amines containing para chloro, bromo, methyl or hydrogen substituents afford the syn amino alcohols as the major diastereomer.