Gas-phase reactions of yttrium and lanthanum ions with alkanes by Fourier transform mass spectrometry

Abstract

The gas-phase reactions of Y+ and La+ with linear, branched, and cyclic alkanes are reported. Dehydrogenation is predominant for ethane and propane while dehydrogenation and carbon-carbon bond cleavage occur for linear and branched alkanes larger than C3. As was observed for the other group 3 metal ion, Sc+, both Y+ and La+ form characteristic dialkyl ions. Evidence is given for two different YC4H6+ and LaC4H6+ isomeric structures. Reaction with cyclopropane gives predominant dehydrogenation products. The observation of LaCH2+ from cyclopropane implies D°(La+-CH2) > 93 kcal/mol. Only dehydrogenation products are observed for cyclopentane and cyclohexane. In general, the primary reactions of Y+ and La+ are found to be similar to those of Sc+. The secondary reactions of La+, however, are found to be considerably slower than those for Sc+ and Y+.

Determination of CaOH and CaOCH3 vibrational branching ratios for direct laser cooling and trapping

“…Internal state cooling and control of polyatomic molecular ions can significantly benefit from laser-induced optical cycling. Polyatomic molecular ions ScOH + , YOH + , as well as ScOCH 3 + and YOCH 3 + , are isoelectronic to the corresponding calcium and strontium compounds [79,80] and should be highly suitable for direct optical manipulation and internal state cooling using methods previously demonstrated with diatomic ions [81]. A few particularly interesting candidates to consider are AcOH + and AcOCH 3 + , which should be similar in electronic structure to RaOH and RaOCH 3 and are sensitive to new physics beyond the standard model [22], but with a significantly longer half-life of the actinium-227 nucleus compared to radium-227 [82].…”

Rare Earth Arene-Bridged Complexes Obtained by Reduction of Organometallic Precursors

“…The synthesis of scandium arene complexes had been limited to the co-condensation of scandium metal vapors and benzene derivatives with bulky substituents (1,3,5-t-Bu3C6H3) (Cloke et al, 1991) or heteroaromatic hydrocarbons (2,4,6-t-Bu3C5H2N and 2,4,6-tBu3C3P3) to give sandwich, formally zero-valent and sub-valent scandium arene complexes (Chart 20) Arnold et al, 1998;Cloke, 1993). The gas-phase reaction of scandium ion with benzene and its derivatives led to products that could only be characterized by mass spectrometry (Huang et al, 1987). Neutral arene scandium(III) complexes supported by -46 diketiminato ligands were isolated and structurally characterized by Piers's group (Chart 21) (Hayes et al, 2003;Hayes et al, 2007).…”

Gas-phase reactions of atomic lanthanide cations with methyl chloride — Periodicities in reactivity

“…Figure 5 demonstrates, in an Arrhenius-like plot, that the reaction efficiency of the Ln + reactions with CH 3 Cl, here measured at constant temperature (295 K), exhibits an exponential dependence on the promotion energy according to eq. [5]. [5] k/k c = exp(-XE p )…”

“…A plethora of investigations into lanthanide ion chemistry followed, in part to further characterize this requirement, but also motivated by general interests in the gas-phase and solution chemistry of lanthanides (2). Reactions of Ln + cations now have been investigated systematically with various inorganic and organic molecules, including hydrogen (3), oxygen (4), nitrous oxide (4), alkanes and cycloalkanes, alkenes (1,5,6), alcohol (7)(8)(9), benzene and substituted benzenes (10,11), phenol (12), orthoformates (10,13), ferrocene, and iron pentacarbonyl (14). Generally these studies show that the reactivity of Ln + varies along the 4f series often in a manner that appears to be determined by the accessibility, through electron promotion, of excited electronic configurations of the Ln + cations with two unpaired non-f electrons.…”