טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentHertzog-Ronen Carmit
SubjectPreparation and Characterization of Novel Pi Conjugated
Systems that Respond to the Presence of Alkylating
Reagents
DepartmentDepartment of Chemistry
Supervisor Professor Yoav Eichen
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


Abstract

The present work reports on the preparation and characterization of novel p conjugated oligomers and polymers and the effect of alkylation process on their optical and electrical properties.

Alkylating agents, such as dimethyl sulfate and alkyl halides are commonly used in organic synthesis as reagents and solvents, soil sterilizers, anticancer drugs and unfortunately also as warfare agents. Owing to their ability to react with many nucleophilic species in the body, most of these materials are toxic and/or mutagenic.

Considering the extensive use and high toxicity of alkylating agents and their potential use as terror warfare agents, the need for simple, sensitive, and informative tools for their detection in solution and in the gas phase becomes apparent.

Several of new p conjugated systems have been prepared. Their properties were characterized using different techniques such as UV-VIS spectroscopy, fluorescence, X-ray diffraction, electronic energy calculations, cyclic voltammetry and differential pulse voltammetry. All of the systems, are composed of bipyridine and pyridine ,as p- acceptor groups and p donor groups, like alkoxy phenyl and thiophene derivatives. After alkylation, charge transfer interaction is occurred as a result of effective and stronger p-acceptor groups which leads to a bathochromic shift in absorbance and fluorescence spectra. These phenomenon of charge transfer interaction was shown in electronic energy calculations of new class of oligomers.

These systems react efficiently with most alkylators, providing sensitivity but only little informative. In order to achieve informatively we have constructed an "artificial nose", includes different sensing materials into an artificial olfactory matrix. This matrix not only reports the presence of alkylating agents in the atmosphere but is capable also of recognizing the specific alkylator that is present in the gas phase.

Polymers based poly(3-hexylthiophene) used as semiconductors in a FET structure. The polymers have shown an OFET behavior with dependence in gate voltage and was typical as hole transport .After the OFET device was exposed to alkylating agent, there was a significant increase in the current with a respective decrease in the voltage effect. This behavior was observed due to changes in the energy levels in the polymers that allowed thermal population and caused doped polymers without dependence in the gate voltage.