Ph.D Thesis

Ph.D StudentCanfi Dorit
SubjectPreparation and Characterization of New Models for
Molecular Switches
DepartmentDepartment of Chemistry
Supervisor ASSOCIATE PROF. Yoav Eichen


Molecular switches draw increasing interest because of their potential application in nanoscopic functional. Molecular switches are characterized in their bistability and their ability to be interconverted between to states by an external stimulus. New thiol/disulfide RedOx switches having pyridinium groups were prepared and characterized. The new thiol/disulfide switches show different affinity toward the complexation of xanthene dyes depending on their RedOx state, therefore they act as RedOx molecular switches. In the oxidized disulfide form, the association ability is strong, thus the complex is in its ”On” state, while in the reduced thiol form the association ability is in its “Off” form.

The analysis of post-explosion residues is one of the most technically difficult subjects in forensic science. Post-explosion analysis is usually characterized by traces of residues present in a complex, highly contaminated matrix. Our approach for the separation and identification of  2,4,6-trinitro toluene (TNT) from post-explosion residues is based on the purification of the post-explosion soup using molecularly imprinted stationary phases. Molecular imprinting is a powerful method for preparing synthetic recognition sites with predetermined selectivity for various substances. When molecularly imprinted polymers are used for chromatographic separations, the imprinted molecule will elute after the other substances in the matrix. New stationary phases for HPLC having anthracene groups were prepared and characterized. The use of the new MIP as stationary phase results in separation of TNT from post-explosion residues. The purification and identification of TNT from post explosion residues was improved in comparison to existing methods, giving a more exact and reliable mass spectra of TNT.