The solid-state structures of CF3(CF2)5CH2CO2H and a fluorous triazole are reported, both of which display a wide variety and large number of noncovalent interactions in their packing. The solid-state structure of CF3(CF2)5CH2CO2H is stabilized by multiple F···F contacts but only one C–H···F–C interaction, as well as O–H···O and C–H···O hydrogen bonds. In contrast to other reported structures, the torsion angles in the fluorous chain are close to 180°, which means that the fluorine atoms are eclipsed. A DFT study of the interactions in both compounds show that F···F interactions, along with stacking and C–H···F and C–H···O contacts, are individually weakly energetically stabilizing, but collectively, they can give rise to interaction energies of up to 13 kcal mol–1. A topological approach to the interactions using atoms-in-molecules (AIM) theory reveals that there are bond critical points between the C–F···F–C interactions as well as C–F···H–C interactions that are not recognized when using only the van der Waals distances.

aWe report that U 3 O 8 , UO 2 (NO 3 ) 2 Á6H 2 O, and UO 2 Cl 2 react with hexachloropropene (HCP) to give UCl 4 in 60, 100, and 92% yields, respectively, and report a protocol to recycle the HCP. This renders the preparation of UCl 4 more accessible and sustainable. 2,5-Dichlorohexachlorofulvene has been identified as a significant by-product from these reactions.In recent years there has been a resurgence of non-aqueous uranium chemistry.1 Such advances rely on the straightforward availability of robust halide starting materials, which are the reagents of choice for introducing new ligand-sets to uranium. For non-aqueous uranium chemistry, straightforward routes to halide starting materials are important because these reagents are not commonly commerically available and must be produced 'in-house'. Apart from uranium(III) triiodide 2 and uranyl(VI) dichloride, 3 perhaps the most commonly used uranium halide starting material is uranium(IV) tetrachloride (UCl 4 ), or solvated derivatives. 4 The latter of these three key starting materials is nowadays prepared by the action of hexachloropropene (HCP) on uranium(VI) trioxide (UO 3 ), since the reaction of carbon tetrachloride on uranium oxides is inconvenient and challenging to undertake on a regular basis. This produces emerald green, solvent-free UCl 4 in high yield. The uranium oxide U 3 O 8 has sometimes been mentioned in the literature as being a suitable starting material for the reaction with HCP. 5 One of us routinely makes UCl 4 by this route in yields of typically 60%. The UCl 4 produced by the UO 3 /HCP route is easily isolated by filtration/washing and is an attractive reagent because the chlorides tend to stabilise the tetravalent state of uranium during reactions, thus suppressing undesirable redox side-reactions. However, the production of UCl 4 from HCP is not without its problems. The reaction initiates via a vigorous radical reaction that produces an exotherm in an already very hot (ca. 200 1C) HCP solution that requires a very long path length condenser to contain, along with brief removal from heat, which in itself requires extra manipulation that may precipitate an accident. In response to this, various variations have been devised, including the portion-wise addition of UO 3 to hot HCP. 4d In principle this circumvents the violent exotherm via a series of much smaller reaction events and can be very effective. However, we note the efficacy of the latter depends on the quality of the UO 3 , and we have found on occasion that particularly wet samples of UO 3 have an induction period. This can risk the build up of unreacted UO 3 , which then suddenly reacts producing an exotherm that might immediately escape out of the flask side arm from which the UO 3 is being introduced. Thus, a safer method can occasionally be turned into a more dangerous one in an unpredictable manner. Increasingly, the use of the UO 3 /HCP reaction is also becoming problematic simply because of the difficulties of obtaining UO 3 , and HCP is becoming increasingly expens...

Three hosts for the encapsulation of perfluorooctanoic acid have been synthesized. The host:guest complexes have been characterized by multinuclear NMR spectroscopy in solution and the solid state.