Inorganic Chemistry, Vol.38, No.1, 165-173, 1999
Actinide gas-phase chemistry: Reactions of An(+) and AnO(+) [An = Th, U, Np, Pu, Am] with nitriles and butylamine
Laser ablation with prompt reaction and detection was applied to study gas-phase reactions of actinide ions, An(+) and AnO(+) [An = Th, U, Pu, Np, Am], with nitriles and butylamine; Tb and Tm were included for comparison. Particular emphasis was on Np and Am as this is the region of the An series where a transition to Ln-like character is manifested. A goal was to assess the role of the coordinating N: site on actinide ion-molecule interactions. The results for the nitriles were generally reminiscent of those for reactions with alkenes and the inert character of Pu+ and Am+ with regard to dehydrogenation, despite adduct formation, indicated that C-H activation requires two non-5f electrons to produce a C-Anf-H complex. With the butyronitriles and valeronitrile, Am+ produced AmC2H4+, possibly via an "ion/dipole" interaction. Most MO+ exhibited only adduct formation with the nitriles although ThO+ was distinctively reactive, consistent with a description of Th as a quasi-d-block element. Both Np+ and Tb+ were substantially effective at dehydrogenating butylamine and Am+ exhibited a lesser degree of reactivity. Reactions of the MO+, TbO+, NpO+, and AmO+ with butylamine revealed a dramatic effect of oxoligation: AmO+ was at least as reactive as TbO+ and NpO+. It is postulated that the MO+ reactions proceeded via a multicentered intermediate without insertion into a C-H bond. Bis-complexes were produced with nitriles and butylamine, attesting to strong complexation with the :N functionality. An ancillary discovery was Am-2(+)-An dimers/clusters should elucidate the nature of actinide intermetallic bonding, including the role of 5f electrons.
Keywords:TRANSITION-METAL IONS;H BOND ACTIVATION;C-C BONDS;LANTHANIDECATIONS;ORGANOMETALLIC CHEMISTRY;HYDROCARBON ACTIVATION;CYCLIC HYDROCARBONS;OXIDATIVE ADDITION;MASS-SPECTROMETRY;OXO-LIGAND