Sol-gel materials: Templated macrostructures and mesostructures by self-assembly and molecular dynamics of photo-induced supramolecular machines

The utilization of sol-gel silica materials in structural templating and as solid supports is discussed in this dissertation. Living yeast cells and synthetic vesicles with uniform size are used as micron and sub-micron size templates, respectively, for preparing macrostructured silica films. The ordered array of immobilized living yeast cells has potential use as a genomic library. The vesicle-templated silica films result in macroporous structure in the film.; The sol-gel silica in the form of monoliths or films serves as a solid support for the supramolecular machines, in particular pseudorotaxanes. The pseudorotaxanes are encapsulated in a sol-gel monolith or chemically attached to a silica film while their photoinduced molecular motion is monitored spectroscopically. The threaded pseudorotaxanes undergo dethreading upon chemical or photochemical reduction. By anchoring pseudorotaxanes onto mesoporous silica films, test molecules trapped in the mesopores are expected to be released controllably upon dethreading. Numerous molecules have been tested and the results documented for the support of this ongoing project.; A photoactive electron donor and an electron acceptor are placed deliberately and simultaneously into two different regions in the mesostructured films templated by surfactants. The structure of the films and the locations of the incorporated molecules are characterized by x-ray diffraction, luminescence properties, and luminescence lifetime.