Formation of thermodynamically stable dications in the gas phase by thermal ion--molecule reactions: Nb sup 2+ with small alkanes

Journal Article · Fri Dec 15 04:00:00 EST 1989 · Journal of Chemical Physics; (USA)

DOI:https://doi.org/10.1063/1.457276· OSTI ID:5040626

Gord, J R; Freiser, B S ^[1]; Buckner, S W ^[2]

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1. Herbert C. Brown Laboratory of Chemistry, Purdue University, West Lafayette, Indiana 47907 (US)
2. Department of Chemistry, University of Arizona, Tucson, Arizona 85710 (US)

The gas-phase reactions of Nb{sup 2+} with small alkanes at thermal energies are reported. For methane and ethane, dehydrogenation is a prominent reaction pathway. For propane and butane, charge transfer is virtually the only reaction pathway observed ({gt}99%). NbCH{sup 2+}{sub 2} and NbC{sub 2}H{sup 2+}{sub 2} formed in the reactions of Nb{sup 2+} with methane and ethane are thermodynamically stable with {ital D}(Nb{sup 2+}--CH{sub 2})=197{plus minus}10 kcal/mol, {ital D}(Nb{sup +}--CH{sup +}{sub 2})=107{plus minus}10 kcal/mol, {ital D}(Nb{sup 2+}--C{sub 2}H{sub 2}){ge}74 kcal/mol, and {ital D}(Nb{sup +}--C{sub 2}H{sup +}{sub 2}){ge}7 kcal/mol. The stability of these ions is most likely due to the charge-stabilizing effect of the metal center. Collision-induced dissociation of these ions results in charge-splitting reactions as well as reactions in which both charges remain on the metal center. Hydride transfer is observed to be competitive in the primary reactions of Nb{sup 2+} with alkanes. The hydride- and charge-transfer results are in qualitative agreement with a simple curve-crossing model.

• OSTI ID: 5040626
• Journal Information: Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Vol. 91:12; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKANES
BUTANE
CHARGE EXCHANGE
CHARGED PARTICLES
CHEMICAL REACTIONS
DEHYDROGENATION
ENTHALPY
ETHANE
FORMATION HEAT
HYDROCARBONS
IONS
MASS SPECTROSCOPY
METHANE
NIOBIUM IONS
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
PROPANE
REACTION HEAT
SPECTROSCOPY
THERMODYNAMIC PROPERTIES