Multifunctional Uranyl Hybrid Materials: Structural Diversities as a Function of pH, Luminescence with Potential Nitrobenzene Sensing, and Photoelectric Behavior as p-type Semiconductors

A series of uranyl organic frameworks (UOFs), {[(UO2)(2)(H(2)TTHA)(H2O)]center dot 4,4'-bipy center dot 2H(2)O}(n) (1), {[(UO2)(3)(TTHA)(H2O)(3)]}(n) (2), and {[(UO2)(5)(TTHA) (HTTHA)(H2O)(3)]center dot H3O}(n), (3), have been obtained by the hydrothermal reaction of uranyl acetate with a flexible hexapodal ligand (1,3,5-triazine-2,4,6-triamine hexaacetic acid, H(6)TTHA). These compounds exhibited three distinct 3D self-assembly architectures as a function of pH by single-crystal structural analysis, although the used ligand was the same in each reaction. Surprisingly, all of the coordination modes of the H(6)TTHA ligand in this work are first discovered. Furthermore, the photoluminescent results showed that these compounds displayed high-sensitivity luminescent sensing functions for nitrobenzene. Additionally, the surface photovoltage spectroscopy and electric-field-induced surface photovoltage spectroscopy showed that compounds 1-3 could behave as p-type semiconductors.