Vibrational spectroscopy investigation of defects in Zr- and Hf-UiO-66
Brandon T. Yost, Bradley Gibbons, Addison Wilson, Amanda J. Morris, L. E. McNeil
Abstract
topology in four defective samples. A monotonic red-shift of the Raman-active Hf-O coordination bond vibration is interpreted as a signature of missing cluster defects, resulting from less-rigid charge-balancing monocarboxylate formate ions replacing the dicarboxylate linker molecule. This signature is hypothesized to be independent of the topology in which the defects appear. Missing linker defects in Zr-UiO-66 are characterized by infrared absorption spectroscopy by the quenching of C-C and C-H vibrational modes confined to the linker molecule. Together, Raman and infrared vibrational spectroscopies coupled with standard characterization techniques are employed to directly probe the nature of defects as well as offer new characterization tools for missing cluster defects in UiO-66.