Gas-phase organolanthanide (Ln) chemistry: Formation of Ln{sup +}-[benzene] and Ln{sup +}-[benzyne] complexes by reactions of laser-ablated Ln{sup +} with cyclic hydrocarbons
- Oak Ridge National Lab., TN (United States)
Nascent laser-ablated lanthanide metal ions, Ln{sup +}, were reacted with cyclohexacarbons. C{sub 6}H{sub 6+2n} (n = 0, 1, 2, or 3), and the resulting organometallic complex ions, [Ln{sup +}] - [C{sub p}H{sub q}], were identified by time-of-flight mass spectrometry. Cyclohexane and cyclohexadiene were especially reactive, primarily undergoing one or more dehydrogenations to produce adduct ions. Also identified as minor products were the `sandwich` complexes. Carbon-carbon bond activation was generally an unimportant reaction channel. Significant differences were observed in product yields and distributions, between the several Ln{sup +} studied, providing the following comparative reactivities: Ce{sup +} >= Tb{sup +} >= Gd{sup +} = Pr{sup +} >= Ho{sup +} >= Dy{sup +} >= Lu{sup +} >= [Sm{sup +}/Tm{sup +}/Eu{sup +}/Yb{sup +} unreactive]. These differences are explained by the metal ion ground state electronic configurations and promotion energies (PE) for excitation of a (nonbonding) 4f electron to a valence 5d orbital. The distinctive Ln{sup +} reactivities indicate that most ablated Ln{sup +} were in the ground or a low-lying electronic state. Contrasting the reactivities of two or more Ln{sup +} co-ablated from a multicomponent target circumvented effects of experimental variables and provided especially reliable comparative reactivities. 52 refs., 4 figs., 5 tabs.
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 405306
- Journal Information:
- Journal of Physical Chemistry, Vol. 100, Issue 39; Other Information: PBD: 26 Sep 1996
- Country of Publication:
- United States
- Language:
- English
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