The control of nanostructured solids: A challenge for molecular chemistry

Nanostructured hybrid organic-inorganic solids are a class of materials of growing interest because of their great potential in synthesis and possible applications. All organic molecules containing at least two -Si(OR)(3) gro ups can be transformed by hydrolytic polycondensation at silicon into mater ials in which the -Si(OR)(3) groups are changed into -SiO1.5. Moreover, the physical properties of the organic units included in the silica matrix are maintained in the solid. This sol-gel-type transformation leads initially to a viscous sol that allows devices to be made (films, matrices and even f ibres in some cases). Finally, these materials exhibit both short-range and long-range organisation in the solid when the organic units have a rigid g eometry.