Open AccessAlkali Metal Salts of 10,12-Pentacosadiynoic Acid and Their Dosimetry Applications
Author(s) -
Amy V. Hall,
Osama M. Musa,
David K. Hood,
David C. Apperley,
Dmitry S. Yufit,
Jonathan W. Steed
Publication year - 2021
Publication title -
crystal growth and design
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.966
H-Index - 155
eISSN - 1528-7505
pISSN - 1528-7483
DOI - 10.1021/acs.cgd.1c00031
Subject(s) - californium , lithium (medication) , denticity , materials science , crystallography , lithium fluoride , inorganic chemistry , chemistry , crystal structure , medicine , physics , quantum mechanics , neutron , endocrinology
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 13 C 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.