Gas-phase synthesis of [OU-X] + (X = Cl, Br and I) from a UO 2 2+ precursor using ion-molecule reactions and an [OUCH] + intermediate.

Difficulty in the preparation of gas-phase ions that include U in middle oxidation states(III,IV) have hampered efforts to investigate intrinsic structure, bonding and reactivity of model species. Our group has used preparative tandem mass spectrometry (PTMS) to synthesize a gas-phase U-methylidyne species, [OUCH] + , by elimination of CO from [UO 2 (CCH)] + [M. J. van Stipdonk, I. J. Tatosian, A. C. Iacovino, A. R. Bubas, L. Metzler, M. C. Sherman and A. Somogyi, J. Am. Soc. Mass Spectrom. , 2019, 30 , 796-805], which has been used as an intermediate to create products such as [OUN] + and [OUS] + by ion-molecule reactions. Here, we investigated the reactions of [OUCH] + with a range of alkyl halides to determine whether the methylidyne is a also a useful intermediate for production and study of the oxy-halide ions [OUX] + , where X = Cl, Br and I, formally U(IV) species for which intrinsic reactivity data is relatively scarce. Our experiments demonstrate that [OUX] + is the dominant product ion generated by reaction [OUCH] + with neutral regents such as CH 3 Cl, CH 3 CH 2 Br and CH 2 CHCH 2 I.