STRUCTURES SURFACE MODIFIED WITH BIDENTATE SILANES

A functionalized support comprising a substrate having a modified surface, characterised in that the substrate surface is modified with a bidentate silane containing at least two silicon atoms bridged by groups so arranged that an at least seven-membered ring system is formed of the following formula: wherein each of R1 to R4, which may be the same or different, represent alkane, substituted alkane, alkene, substituted alkene, aryl or substituted aryl; Y represents -O-, -CH2-, -CH2CH2-, -(CH2)n, -(CHZ-CHZ)- or -(CH2)nCHZ-, where Z represents alkane, substituted alkane, alkene, substituted alkene, aryl, substituted aryl, halogen, hydroxyl, hydrogen, nitrile, primary, secondary or tertiary or tetralkylamine, carbonyl, carboxyl, amide, sulfonic acid, nitro, nitroso, amide or sulfonamide, and n is 1 to 6; and A represents the atoms on the substrate surface to which the silane is covalently attached, subject to the proviso that when Y is -O- R1 to R4 do not all represent methyl finds use in, for example, chromatographic separations.