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

Abstract Four new uranyl complexes, [(UO 2 )(DMSO)( p -MBA) 2 ] 2 ( 1 ), [(UO 2 )(DMSO)( p -MBA) 2 ] 2 ( 2 ), [(UO 2 )(DMSO)( m -MBA) 2 ] 2 ( 3 ) and [(UO 2 )(H m -MBA)( m -MBA) 2 ] 2 ( 4 ) (H p -MBA =  p -toluylic acid, H m -MBA =  m -toluylic acid, DMSO = Dimethyl sulfoxide), were synthesized. Structural analyses reveal that four complexes have similar structures of which two penta-coordinated ((UO 2 )(O DMSO )(O L ) 2 in 1 – 3 and (UO 2 )(O HL )(O L ) 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, C 2/ 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.