Alkali Metal Salts of 10,12-Pentacosadiynoic Acid and Their Dosimetry Applications

Hall, Amy V.; Musa, Osama M.; Hood, David K.; Apperley, David C.; Yufit, Dmitry S.; Steed, Jonathan W.

Abstract

Wide-dose-range 2D radiochromic films for radiotherapy, such as GAFchromic EBT, are based on the lithium salt of 10,12-pentacosadiynoic acid (Li-PCDA) as the photosensitive component. We show that there are two solid forms of Li-PCDA—a monohydrated form A and an anhydrous form B. The form used in commercial GAFchromic films is form A due to its short needle-shaped crystals, which provide favorable coating properties. Form B provides an enhanced photoresponse compared to that of form A, but adopts a long needle crystal morphology, which is difficult to process. The two forms were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, CP-MAS 13C solid-state NMR spectroscopy, and thermogravimetric analysis. In sum, these data suggest a chelating bridging bidentate coordination mode for the lithium ions. The sodium salt of PCDA (Na-PCDA) is also reported, which is an ionic cocrystal with a formula of Na+PCDA–·3PCDA. The PCDA and PCDA– ligands display monodentate and bridging bidentate coordination to the sodium ion in contrast to the coordination sphere of the Li-PCDA forms. In contrast to its lithium analogues, Na-PCDA is photostable.

Citation

Hall, A. V., Musa, O. M., Hood, D. K., Apperley, D. C., Yufit, D. S., & Steed, J. W. (2021). Alkali Metal Salts of 10,12-Pentacosadiynoic Acid and Their Dosimetry Applications. Crystal Growth and Design, 21(4), 2416-2422. https://doi.org/10.1021/acs.cgd.1c00031

• Journal Article Type: Article
• Online Publication Date: Mar 25, 2021
• Publication Date: Apr 7, 2021
• Deposit Date: Oct 27, 2021
• Publicly Available Date: Mar 25, 2022
• Journal: Crystal Growth and Design
• Print ISSN: 1528-7483
• Electronic ISSN: 1528-7505
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 21
• Issue: 4
• Pages: 2416-2422
• DOI: https://doi.org/10.1021/acs.cgd.1c00031
• Public URL: https://durham-repository.worktribe.com/output/1230066