Uranyl nitrate complexes with diphenylsulfoxide and dibenzylsulfoxide: characterization, luminescence and structures

Abstract

Uranyl nitrate complexes with diphenylsulfoxide (DPSO) and dibenzylsulfoxide (DBSO) were synthesized and characterized by CHN elemental analyses, infrared absorption spectra, X-ray powder diffraction, visible luminescence spectra and thermal analyses (TG and DTG). The complexes present the compositions UO2(NO3)2(DPSO)2 and UO2(NO3)2(DBSO)2. Infrared spectra show a shift of νSO to lower frequencies, indicating bonding through the sulfoxide oxygen. The nitrate bands indicate that they are coordinated as bidentate ligands. In both complexes thermal decomposition yields U3O8 as final product. Both complexes present a strong green luminescence, both at room temperature and 77K, presenting four bands with vibronic structures partially resolved at low temperature.The X-ray powder patterns of these complexes are different, therefore, both structures were determined by single-crystal X-ray diffraction. In both complexes the U(VI) occupies a symmetry center. Uranyl oxygen atoms, nitrate ions and neutral ligands are perpendicular with respect to each other.