Synthesis and crystal structure of UO2Cl2(THF)3: A simple preparation of an anhydrous uranyl reagent

Solid state Structures of molecular uranyl compounds are commonly described in the literature. The vast majority of these species have been isolated from aqueous media, and the presence of water often influences the resulting structures through hydrogen bonding and/or inner-sphere water coordination. The development of nonaqueous uranyl chemistry has demonstrated the existence of novel coordination geometries in the absence of these effects. Further studies are required to examine the potentially unique electrochemical and spectroscopic properties of these products. Until recently, the development of nonaqueous uranyl chemistry has been inhibited by a lack of appropriate starting materials. Several thermal routes for the synthesis of anhydrous UO2Cl2 have been reported. However, they are generally unsuitable for the generation of reagents because of difficulties encountered separating precursors and/or side products from UO2Cl2, the unavailability of a commercial source for starting materials, e.g., UCl4, or the limited scale of preparation. The authors have been interested in the development of nonaqueous uranyl chemistry in order to examine physical properties of uranyl species unstable to hydrolysis. The expansion of this chemistry has been facilitated by the development of a simple one-pot dehydration of UO2Cl2·x(H2O) (x = 1,3) for the preparation of UO2Cl2(THF)3 (1). The previously reported dimeric derivative, [UO2Cl2(THF)2]2 (2), may be isolated upon desolvation of 1. Compound 2 is an excellent starting material for the further synthesis of uranyl alkoxides and uranyl amides