Cation-ether complexes in the gas phase: Bond dissociation energies and equilibrium structures of Li{sup +} (1,2-dimethoxyethane){sub x}, x= 1 and 2, and Li{sup +}(12-crown-4)
- Pacific Northwest National LAb., Richland, WA (United States)
- Univ. of Utah, Salt Lake City, UT (United States)
Bond dissociation energies, equilibrium structures, and harmonic vibrational frequencies are reported for Li{sup +}(DXE), where DXE= CH{sub 3}O(CH{sub 2}){sub 2}OCH{sub 3}, Li{sup +}(DXE){sub 2}, and Li{sup +}(12-crown-4). The bond dissociation energies are determined experimentally by analysis of the thresholds for collision-induced dissociation of the cation-ether complexes by xenon (measured using guided ion beam mass spectroscopy) and computationally by ab initio electronic structure calculations. For Li{sup +}(DXE){sub x}, x= 1 and 2, the primary and lowest energy dissociation channel observed experimentally is endothermic loss of one dimethoxyethane molecule. For Li{sup +}(12-crown-4), the primary dissociation channel is endothermic loss of the intact crown ether, although ligand fragmentation is also observed. The cross section thresholds are interpreted to yield 0 and 298 K bond energies after accounting for the effects of multiple ion-molecule collisions, internal energy of the complexes, and unimolecular decay rates. The calculated and experimentally-derived bond energies are in good agreement for Li{sup +}(DXE), are in reasonable agreement for Li{sup +}(12-crown-4), and differ by 32{+-}12 kJ/mol for Li{sup +}(DXE){sub 2}. The equilibrium structures are determined primarily by strong electrostatic and polarization interactions between Li{sup +} and the ligands. 65 refs., 7 figs., 5 tabs.
- DOE Contract Number:
- AC06-76RL01830; FG06-89ER75522
- OSTI ID:
- 420878
- Journal Information:
- Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 40 Vol. 100; ISSN JPCHAX; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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