Gas-Phase Actinide Ion Chemistry:  FT-ICR/MS Study of the Reactions of Thorium and Uranium Metal and Oxide Ions with Arenes

Abstract

Gas-phase reactions of M+, M2+, MO+ (M = Th and U), and UO2 + with several arenes (benzene, naphthalene, toluene, mesitylene, hexamethylbenzene, and 1,3,5-tri-tert-butylbenzene) have been studied by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR/MS). For M+ ions C−H and/or C−C bond activation was observed in the primary reactions for all of the arenes studied. MO+ and UO2 + ions yielded the adduct species, with the exceptions of the reactions of MO+ with hexamethylbenzene and 1,3,5-tri-tert-butylbenzene, for which bond activation products also formed. In the M2+ reactions charge-transfer products dominated, but formation of doubly charged bond activation products was also observed with all the arenes. Product distributions and reaction rate constants are reported and related to the electronic configurations of the reacting ions, the polarizabilities of the arenes, and the energetics of the different reactions.

Preparation and Reactions of Base-Free Bis(1,2,4-tri-tert-butylcyclopentadienyl)uranium Oxide, Cp‘2UO

“…[6][7][8][9] In addition to providing reactivity patterns, these gas phase studies yield useful thermodynamic bond disruption enthalpies for the U-O bonds which lie in the range of 120-190 kcal mol -1 . [6][7][8][9] This paper describes the synthesis of base-free [η 5 -1,2,4-(Me 3 C) 3 C 5 H 2 ] 2 UO (10), Cp' 2 UO, and some of its reactions with silyl-and alkylhalides. These reactions provide a molecular model for the heterogeneous reaction of solid U 3 O 8 and chlorocarbons that results in complete destruction of the latter to CO x and HCl.…”

“…reaction of Cp' 2 UO(py) (8) and Me 3 SiCl in toluene followed by crystallization from pentane, or reaction of Cp' 2 UCl 2 (1) with one equiv of LiOSiMe 3 in diethyl ether followed by crystallization from pentane. Synthesis and characterization details for this and the other metallocenes described in this section are given in the Experimental Section, and some physical properties are listed in Table 1.…”

Reactions of actinide ions with ethylene oxide

“…However, among the actinides, even the relatively weak Am—O bond has an estimated dissociation energy of ∼550 kJ mol −1 ,13 which precludes oxidation of most organics 11c. Accordingly, the effects of oxo ligation on actinide ion reactivities towards organics is expected to generally result in non‐insertion mechanisms such as have been identified for LnO + (Ln = lanthanide) and AnO + 1, 11, 14, 15…”

Ions generated from uranyl nitrate solutions by electrospray ionization (ESI) and detected with fourier transform ion-cyclotron resonance (FT-ICR) mass spectrometry

“…Many of these studies have focused on the reactions of U ϩ and UO ϩ with alkanes [6,7], alkenes [8], alcohols, thiols and ethers [9], arenes [10], and other small molecules [11][12][13][14][15][16]. Recently, the hydration reactivities of UO ϩ , UO 2 ϩ , and UO 2 2ϩ were examined using secondary ion mass spectrometry [17].…”