Gas-phase ion-molecule reactions of lanthanides with crown ethers

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:210647

White, F M; Xin, Tianpei; Marshall, A G ^[1]

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1. Florida State Univ., Tallahassee, FL (United States)

The authors report gas-phase ion-molecule reactions of lanthanide ions, M{sup +} (e.g La, Ho, Pr, Sm, and Gd) with neutral 18-crown-6 ether. Previously, the lanthanide ion electronic configuration was found to control the reaction pathways and distribution of the product ions for reactions of lanthanide ions with tri-t-butylbenzene. Here, FT-ICR mass spectra were acquired in the source compartment of a dual-trap 3.0 tesla Extrel FTMS-2000 (Extrel FTMS/Waters, Madison, WI) equipped with an automatic solids insertion probe. Metal ions were generated by laser desorption with a Nd:YAG laser (Surelite II, Continuum Inc., Santa Clara, CA) operating at 1064 nm with a pulse width of 7 ns. A constant pressure of crown ether in the source-side ion trap was generated by dissolving the 18-crown-6 in acetone and applying it to the back side of a standard Extrel probe tip. After allowing the acetone to evaporate, praseodymium metal was applied to the front of the probe tip with double-sided adhesive tape. This configuration gave a fairly constant pressure of {approximately}5x10{sup -8} torr (background pressure {approximately}2xl0{sup -8} torr) for {approximately}1 h. After desorption of the metal ions, a variable length time delay allowed for reactions of the metal ion with crown ether neutrals. Following formation of metal:crown ether fragment complexes, collision-activiated dissociation yielded metal oxide ions which could subsequently be isolated and allowed to react again with crown ether neutrals. In this way, {open_quotes}hot{close_quotes} (reactions within several milliseconds after desorption) metal oxide ions with crown ether neutrals and {open_quotes}cold{close_quotes} (reaction at least 5 seconds after desorption) metal oxide ions reactions with crown ether neutrals could be compared.

• OSTI ID: 210647
• Report Number(s): CONF-9505261--
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
CHEMICAL REACTIONS
CROWN ETHERS
ION-MOLECULE COLLISIONS
MASS SPECTROSCOPY
PRASEODYMIUM