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. Par ticular emphasis was on Np and Am as this is the region of the An series wh ere a transition to Ln-like character is manifested. A goal was to assess t he role of the coordinating N: site on actinide ion-molecule interactions. The results for the nitriles were generally reminiscent of those for reacti ons with alkenes and the inert character of Pu+ and Am+ with regard to dehy drogenation, despite adduct formation, indicated that C-H activation requir es two non-5f electrons to produce a C-Anf-H complex. With the butyronitril es and valeronitrile, Am+ produced AmC2H4+, possibly via an "ion/dipole" in teraction. Most MO+ exhibited only adduct formation with the nitriles altho ugh 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 dram atic effect of oxoligation: AmO+ was at least as reactive as TbO+ and NpO+. It is postulated that the MO+ reactions proceeded via a multicentered inte rmediate without insertion into a C-H bond. Bis-complexes were produced wit h nitriles and butylamine, attesting to strong complexation with the :N fun ctionality. An ancillary discovery was Am-2(+)-An dimers/clusters should el ucidate the nature of actinide intermetallic bonding, including the role of 5f electrons.