A Family of Uranyl Coordination Polymers Containing O‑Donor Dicarboxylates and Trispyridyltriazine Guests

Four uranyl coordination polymers [UO₂(C₆H₈O₄)­(H₂O)₂]­(C₁₈H₁₂N₆)₂ (<b>1</b>), [UO₂(C₈H₄O₄)­(H₂O)₂]­(C₁₈H₁₂N₆)₂ (<b>2</b>), Na­[(UO₂)­(C₁₂H₆O₄)₂]­(C₁₈H₁₃N₆)­·H₂O (<b>3</b>), and Na­[(UO₂)­(C₁₆H₈O₄)­(C₆H₃NO₂)]­(C₁₈H₁₂N₆)­·H₂O (<b>4</b>) containing aliphatic (adipic acid) or aromatic linkers (1,4-benzene dicarboxylic acid (BDC), 1,4-napthalene dicarboxylic acid (NDC), anthracene 9,10-dicarboxylic acid (ADC)) were synthesized and characterized using single crystal X-ray diffraction, powder X-ray diffraction, and luminescence spectroscopy. The π-stacking distances or the number of π–π interactions present between trispyridyltriazine (TPTZ) guests or the host framework in <b>1</b>–<b>4</b> may be affected by the size of the O-donor linker (adipic acid < BDC < NDC < ADC). Luminescence studies show that substitution between adipic acid and BDC influences the emission of <b>1</b> and <b>2</b>, in which the emission of <b>1</b> shows a red shift relative to that of <b>2</b>. Uranyl emission was not observed in <b>3</b> and <b>4</b>, and may be attributed to the position of the NDC and ADC triplet state relative to the emissive uranyl species