Uranium(VI) hybrid materials with [(UO2)3(µ3-O)(µ2-OH)3]+ as the sub-building unit via uranyl-cation interactions

The hydrothermal reaction of uranyl nitrate with 1,4-benzenedicarboxylic acid (H 2bdc) in the presence of strontium or potassium hydroxides and nitrates afford the formation of two new uranyl hybrid materials featuring extensive uranyl-strontium or uranyl-potassium interactions with [(UO 2) 3(µ 3-O)(µ 2-OH) 3] + as the sub-building unit. Sr 1.5[(UO 2) 12(O) 3(OH) 13(bdc) 4]⋅6H 2O (1) contains one-dimensional (1D) uranyl oxohydroxyl ribbons made of trinuclear pentagonal bipyramidal uranyl units. The ribbons are linked together via uranyl-strontium interactions to form 2D inorganic domains which are further connected through µ 4-bdc anions forming a 3D hybrid structure. This is the first reported uranyl-strontium interaction in extended hybrid solid with the shortest Sr-O −yl bond length of 2.596 (8) Å. K 3[(UO 2) 12(O) 3(OH) 13(bdc) 4]⋅8H 2O (2) has a similar 3D hybrid structure built up through extensive K-O −yl interactions with the shortest K-O −yl bond length of 2.620 (6) Å. Raman spectroscopy has confirmed the presence of oxo-bridging (U−O−U) vibrations. Thermal stabilities and photoluminescent properties are reported.