Unprecedented Radiation Resistant Thorium–Binaphthol Metal–Organic Framework
Sara E. Gilson, Melissa Fairley, Patrick Julien, Allen G. Oliver, Sylvia L. Hanna, Grace Arntz, Omar K. Farha, Jay A. LaVerne, Peter C. Burns
Abstract
A thorium–organic framework (TOF-16) containing hexameric secondary building units connected by functionalized binaphthol linkers was synthesized, characterized, and irradiated to probe its radiation resistance. Radiation stability was examined using γ-rays and 5 MeV He2+ ions to simulate α particles. γ-irradiation of TOF-16 to an unprecedented 4 MGy dose resulted in no apparent bulk structural damage visible by X-ray diffraction. To further probe radiation stability, we conducted the first He2+ ion irradiation study of a metal–organic framework (MOF). Diffraction data indicate onset of crystallinity loss upon approximately 15 MGy of irradiation and total loss of crystallinity upon exposure to approximately 25 MGy of He2+ ion irradiation. The high radiation resistance observed suggests MOFs can withstand radiation exposure at doses found in nuclear waste streams and highlights the need for a systematic approach to understand and eventually design frameworks with exceptional radiation resistance.