Intrinsic reactivity of [OUCH]+ : Apparent synthesis of [OUS]+ by reaction with CS2

RATIONALE

Building on our report that collision-induced dissociation (CID) can be used to create the highly reactive U-alkylidyne species [O=U≡CH]⁺ , our goal was to determine whether the species could be as an intermediate for synthesis of [OUS]⁺ by reaction with carbon disulfide (CS₂ ).

METHODS

Cationic uranyl-propiolate precursor ions were generated by electrospray ionization, and multiple-stage CID in a linear trap instrument was used to prepare [O=U≡CH]⁺ . Neutral CS₂ was admitted into the trap through a modified He inlet and precision leak valves.

RESULTS

The [O=U≡CH]⁺ ion reacts with CS₂ to generate [OUS]⁺ . CID of [OUS]⁺ causes elimination of the axial sulfide ligand to generate [OU]⁺ . Using isotopically labeled reagent, we found that [OUS]⁺ reacts with O₂ to create [UO₂ ]⁺ .

CONCLUSIONS

[O=U≡CH]⁺ proves to be a useful reagent ion for synthesis of [OUS]⁺ , a species that to date has only been created by gas-phase reactions of U⁺ and U²⁺ . Dissociation of [OUS]⁺ to create [OU]⁺ , but not [US]⁺ , and the efficient conversion of the species into [UO₂ ]⁺ , is consistent with the relative differences in U-O and U-S bond energies.

Intrinsic chemistry of [OUCH]+: reactions with H2O, CH3C[triple bond, length as m-dash]N and O2

We report the first experimental study of the intrinsic chemistry of a U-methylidyne species, focusing on reaction of [OUCH]+ with H2O, O2 and CH3C[triple bond, length as m-dash]N in the gas phase. DFT was also used to determine reaction pathways, and establish the mechanism by which [OUCH]+ is formed through collision-induced dissociation of [UO2(C[triple bond, length as m-dash]CH)]+.