Intrigued by the reactivity of 3 towards electrophiles, we examined the reactivity of 2 towards CO2 and silyl electrophiles. The reactivity of 2 was investigated towards silylating agents to evaluate the possibility of decoordination and liberation of the anionic oxocarbon ligand. It should be noted that decoordination of CO reduction products from oxophilic U(IV) metal centers has been successfully achieved upon treatment with silyl electrophiles. No reaction occurred upon addition of excess Me3SiCl to 2, even upon heating to 80 °C. In contrast, the addition of Me3SiOTf to a solution of 2 in toluene-d8 led to a complete conversion after 15 h at room temperature (Scheme 4). Analysis of the crude product by The bond distances within the oxygen heterocycle are consistent with a conjugated system and delocalization of one negative charge over O2 and O4, similar to the case in b-diketonate ligands. As a result, the C1-C2 and C2-C3 bond distances are almost identical (1.397(3) and 1.396(3) Å, respectively), as are the O2-C1 and O4-C3 bond distances (1.280(3) and 1.290(3) Å, respectively). In contrast, the unconjugated O3-C2 bond is longer with a distance of 1.339(3) Å. The Tm-O bond distances are lying in the range 2.200(2)-2.333(2) Å. The paramagnetic 1 H NMR spectrum of 7 features a complex baseline over the temperature range 20-80 °C (see Figure ), which results from the low symmetry of the complex in solution. In the IR spectrum, the coordinated b-diketonate group gives rise to an intense absorption band at 1639 cm -1 .