Photofragmentation of thecloso-Carboranes Part II: VUV Assisted Dehydrogenation in thecloso-Carboranes and Semiconducting B10C2HxFilms

Rühl, E; Riehs, NF; Behera, S; Wilks, J; Liu, J; Jochims, HW; Caruso, AN; Boag, NM; Kelber, J A; Dowben, P A

Abstract

The dehydrogenation of semiconducting boron carbide (B10C2
Hx) films as well as the three closo-carborane isomers
of dicarbadodecaborane (C2
B10H12) and two isomers of the corresponding closo-phosphacarborane (PCB10H11) all
appear to be very similar. Photoionization mass spectrometry studies at near-threshold gas phase photoionization
indicate that the preferred pathway for dissociation of the parent cation species (C2
B10H10
+ or PCB10H9
+) is, in all
cases, the loss of H2. Ab initio density functional theory (DFT) calculations indicate that energetically preferred
sites for exopolyhedral hydrogen (B-H) bond dissociation are in all cases at B atoms opposite the C atoms in the
parent cage molecule. The site of photodissociation of hydrogen from semiconducting boron carbide (B10C2
Hx)
films, fabricated by plasma-enhanced chemical vapor deposition, is a cage boron atom that can bond to nitrogen
upon exposure to VUV light in the presence of NH3. Shifts in core level binding energies due to nitrogen bond
formation indicate that B-N bond formation occurs only at B atoms bound to other boron atoms (B-B sites) and
not at B-C sites or at C sites, in agreement with gas phase results.

Citation

Rühl, E., Riehs, N., Behera, S., Wilks, J., Liu, J., Jochims, H., …Dowben, P. A. (2010). Photofragmentation of thecloso-Carboranes Part II: VUV Assisted Dehydrogenation in thecloso-Carboranes and Semiconducting B10C2HxFilms. Journal of Physical Chemistry A, 114(27), 7284-7291. https://doi.org/10.1021/jp103805r

• Journal Article Type: Article
• Publication Date: Jan 1, 2010
• Deposit Date: Nov 7, 2014
• Journal: The Journal of Physical Chemistry A
• Print ISSN: 1089-5639
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 114
• Issue: 27
• Pages: 7284-7291
• DOI: https://doi.org/10.1021/jp103805r
• Publisher URL: http://dx.doi.org/10.1021/jp103805r
• Additional Information: Funders : Funder not known