The asymmetric ONNO complexes of dioxouranium(VI) with N1,N4-diarylidene-S-propyl-thiosemicarbazones derived from 3,5-dichlorosalicylaldehyde: Synthesis, spectroscopic and structural studies

Two uranyl complexes having the composition [UO2(L)DMSO] were synthesized using salicyl- and 3,5-dichlorosalicylaldehyde-S-propyl-thiosemicarbazones as starting materials. The S-propyl-thiosemicarbazidato structures in the complexes are N1-3,5-dichlorosalicylidene-N4-salicylidene and N1-salicylidene-N4-3,5-dichlorosalicylidene. The stable solid complexes were characterized by means of elemental analysis, IR and 1H NMR spectroscopies, and the single crystal X-ray diffraction technique. The two complexes, with the same formula, crystallize in different space groups. In the title complexes, the uranium atom is seven-coordinated in a distorted pentagonal-bipyramidal geometry involving an ONNO donor set of the thiosemicarbazidato ligand and an oxygen atom of a DMSO molecule. The two apical positions of the pentagonal bipyramid are occupied by the two oxygen atoms of the trans-dioxouranium group. The relative orientations of the DMSO and S-propyl groups in both complexes are somewhat different due to different crystal packing.

Two isomeric uranyl complexes possessing a composition of [UO2(L)DMSO] have been synthesized and characterized by means of elemental analysis, IR and 1H NMR spectroscopies. The crystal structures of the complexes have been determined by the single crystal X-ray diffraction technique, and structural differences between them have been investigated.Figure optionsDownload as PowerPoint slideResearch highlights
► The complexes are stable in air, soluble in alcohols and chlorinated hydrocarbons.
► The complexes are non-electrolytes in DMSO with low conductance values.
► The orientations of the DMSO and S-propyl groups are affected by crystal packing.