Isotopic labeling as a tool to establish intramolecular vibrational coupling: The reaction of 2-propanol on Mo(110)

Journal Article · Tue Dec 01 04:00:00 EST 1992 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.463392· OSTI ID:7037712

Uvdal, P; Wiegand, B C; Serafin, J G; Friend, C M ^[1]

---

1. Department of Chemistry, Harvard University, Cambridge, Massachusetts 02138 (United States)

The reactions of 2-propanol on Mo(110) were investigated using temperature programmed reaction, high resolution electron energy loss, and x-ray photoelectron spectroscopies. 2-Propanol forms 2-propoxide upon adsorption at 120 K on Mo(110). The 2-propoxide intermediate deoxygenates via selective {gamma} C--H bond scission to eliminate propene as well as C--O bond hydrogenolysis to form trace amounts of propane. The C--O bond of 2-propoxide is estimated to be nearly perpendicular to the surface. Selective isotopic labeling was used to establish the coupling between the C--O stretch and modes associated with the hydrocarbon framework. The degree of coupling was strongly affected by bonding to the surface, primarily due to weakening of the C--O bond when 2-propoxide is bound to Mo(110). Selective isotopic labeling was, therefore, essential in making vibrational assignments and in identifying key reaction steps. Only a small kinetic isotope effect was observed during reaction of (CD{sub 3})(CH{sub 3})CHOH, consistent with a substantial component of C--O bond breaking in the transition state for propene elimination. Coupling of the C--O stretch to motion of the methyl group is also suggested to be important in the transition state for propene elimination.

• DOE Contract Number: FG02-84ER13289
• OSTI ID: 7037712
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 97:11; 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
ADSORPTION
ALCOHOLS
CHEMICAL BONDS
CHEMICAL REACTIONS
DEUTERIUM
ELECTRON SPECTROSCOPY
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
ENERGY LEVELS
ENERGY LOSSES
EXCITED STATES
FERMIONS
HYDROGEN ISOTOPES
HYDROXY COMPOUNDS
INTERATOMIC FORCES
ISOTOPE EFFECTS
ISOTOPES
LEPTONS
LIGHT NUCLEI
LOSSES
METALS
MOLYBDENUM
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
PROPANOLS
RESOLUTION
SORPTION
SPECTROSCOPY
STABLE ISOTOPES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0065-0273 K
TRANSITION ELEMENTS
ULTRAHIGH VACUUM
VIBRATIONAL STATES