Four new dinuclear uranyl complexes based on p- and m-toluic acid: Syntheses, structures, luminescent and photocatalytic properties

•Four uranyl complexes feature a similar dinuclear structure.•Compounds 1 and 2 display promising photocatalytic properties.•2 Proves high catalytic activity under the irradiation of natural sunlight.

Four new uranyl complexes, [(UO2)(DMSO)(p-MBA)2]2 (1), [(UO2)(DMSO)(p-MBA)2]2 (2), [(UO2)(DMSO)(m-MBA)2]2 (3) and [(UO2)(Hm-MBA)(m-MBA)2]2 (4) (Hp-MBA = p-toluylic acid, Hm-MBA = m-toluylic acid, DMSO = Dimethyl sulfoxide), were synthesized. Structural analyses reveal that four complexes have similar structures of which two penta-coordinated ((UO2)(ODMSO)(OL)2 in 1–3 and (UO2)(OHL)(OL)2 in 4) uranyl units bridged by two benzoic acid ligands forming dinuclear units. Compounds 1 and 2 belong to two kinds of polymorph forms, C2/c and P  1¯ space groups, respectively. The supramolecular structures of 1–4 are assembled into 3D network by hydrogen bond interactions and π⋯π stacking interactions. Furthermore, the photocatalysis properties of 1 and 2 for degradation of the rhodamine-B (RhB) upon 500 W xenon lamp irradiation have been examined. Elemental analysis, infrared spectroscopy, thermogravimetric analysis, DRS and luminescence properties were also discussed.

Graphical abstractFour new uranyl dinuclear complexes based on p- and m-toluic acid have been synthesized. As polymorph, 1 and 2 prove useful to degrade RhB under the irradiation of simulate daylight by 500 W xenon lamps. It is notable that high activity is achieved under the natural sunlight irradiation for 2. Elemental analyses, infrared spectrum, thermogravimetric analyses, DRS and luminescence properties were also discussed.Figure optionsDownload full-size imageDownload as PowerPoint slide