Synthesis and Structural Characterization of the Monodentate 12-Crown-4 And Hexaethylene Glycol Complexes of Uranium(VI): [UO2Cl2(OH2)2(12-CROWN-4)].12-Crown-4 And UO2Cl2(OH2)2(Hexaethylene Glycol)

The reaction of anhydrous UO 2 Cl 2 with 12-crown-4 or hexaethylene glycol (EO6) in THF with low water content resulted in the crystallization of [UO 2 Cl 2 (OH 2 ) 2 (12-crown-4)]. 12-crown-4 and UO 2 Cl 2 (OH 2 ) 2 (EO6). The crystal structures of both complexes were determined. Each complex consists of a uranyl ion coordinated to two chloride anions, two water molecules, and one oxygen of the polyether. Most of the uncoordinated ether oxygen atoms participate in hydrogen bonding. The hydrogen bonding in the 12-crown-4 complex produces a dimer, while the hydrogen bonding in the EO6 complex is polymeric. The etheric U-O separation of 2.546(4) Å in the 12-crown-4 complex is the longest U-O contact in either complex, while the alcoholic U-O distance in the EO6 complex is a much shorter 2.433(5) Å.