Abstract

This thesis entitled " Design of new hybrid materials: Study of its application in new detection formats and in controlled release applications”, is focused on the development of new functional hybrid organic-inorganic materials based on the combination of Supramolecular Chemistry and Materials Science principles. 

The first part of the thesis is focused on the design and preparation of new materials with the ability to control the access to their surface using concepts of Supramolecular Chemistry. These systems are based on silica supports containing two different groups, one group that act as a reactive center, and it is able to produce a measurable change in color or fluorescence upon reaction with a selected dye. The other group modulates the access of dye to the surface upon a change in the media or after addition of certain target species. Bearing in mind this proposed system, we selected squaraines as reporter molecules and thiols as reactive centers, due to the change in color produced upon reaction between both species. On the other hand, the first host selected was polyamines as binding sites in order to detect anionic species. Coordination of polyamines with anions modulates the access of squaraine to the thiols anchored onto silica surface and, with this, detection of these species in solution is achieved. Using the same recognition protocol, another hybrid material for the colorimetric detection of anionic surfactants in water is prepared, using in this case imidazolium groups as binding sites.

The other part of the thesis is focused on the design, synthesis and characterization of new hybrid materials than acts as molecular gates for the detection of chemical species. Prepared materials can store a dye inside of the pores. Upon application of a stimulus that triggers the release, such as the presence of small molecules, dye can be released to the solution. Using  this concept, in the second chapter is reported the synthesis of a novel probe device for methylmercury detection, using a molecular gated hybrid solid, bearing in mind the strong affinity between methylmercury and thiol moieties. In the third chapter, three hybrid organic-inorganic mesoporous materials that are triggered by antigen-antibody immunological process are showed, allowing the detection of the antigens sulfathiazole (an antibiotic of the sulfonamides family), finasteride (a 5?-reductase inhibitor) and TATP (an explosive). Finally, and bearing in mind DNA hybridisation process, the last chapter presents a material in which the release is triggered by recognition between two oligonucleotides. 

In summary, the new hybrid organic-inorganic solids described in this thesis offers new detection format for chemical species. On the other hand, preparation of hybrid materials for controlled guest release in the presence of  antibodies or oligonucleotides offers the possibility to apply these nanodevicess in analytical chemistry, biotechnology or in clinical diagnostic field.