Solid State Reactivity of Dialkyne Dosimeters

Radiation dosing is conveniently and easily measured by means of a solid state dosimeter that undergoes a chemical reaction stimulated by the incident radiation. An example in extensive commercial use is Pentacosadiynoic Acid (PCDA) which undergoes a readily visualized colour change from colourless to blue upon exposure to gamma radiation. This compound is used in sensors for blood irradiation and in radiotherapeutic films such as Gafchromic. The chemical change involved carbon-carbon bond formation in the solid crystals. The sensitivity of dialkyne compounds such as this to radiation-induced reactivity is highly dependent on the arrangement of the molecules in the crystal structure. This project seeks to understand the relationship between radiation sensitivity and crystal structure in various solid state forms and salts of PCDA and to use a cocrystallization strategy to explicitly tailor the solid state placement of radiation-sensitive dialkynes in order to optimize radiation sensitivity as well as expand this technology to other dosimetry fields. In particular the project will use topochemical and crystal engineering principles to systematically design crystal structure for tailored conversion characteristics upon exposure to different radiation sources.