Alkali metal salts of 10,12-pentacosadiynoic acid and their dosimetry applications

DOI: 10.1021/acs.cgd.1c00031

Authors: Amy V. Hall (Durham University) , Osama M. Musa (Ashland LLC) , David K. Hood (Ashland LLC) , David C. Apperley (Durham University) , Dmitry Yufit (Durham University) , Jonathan W. Steed (Durham University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Crystal Growth & Design , VOL 21 , PAGES 2416-2422

State: Published (Approved)
Published: March 2021
Diamond Proposal Number(s): 22240

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.

Subject Areas: Chemistry, Materials


Instruments: I19-Small Molecule Single Crystal Diffraction

Added On: 29/03/2021 11:21

Documents:
acs.cgd.1c00031.pdf

Discipline Tags:

Chemistry

Technical Tags:

Diffraction Small Molecule Diffraction