Effect of fluorination on thiol reactivity: Reaction of 4,4,4-trifluorobutanethiol on Mo(110)

Langmuir

Volumn 12, Issue 7, 1996, Pages 1800-1806

  Napier, M E ^a   Friend, C M ^a  

^a HARVARD UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

CATALYSIS; CHEMICAL BONDS; CHEMICAL REACTIONS; DECOMPOSITION; FLUORINE COMPOUNDS; MOLYBDENUM; ORGANIC COMPOUNDS; SURFACE PHENOMENA;

BOND STRENGTH; FLUORINATION; REACTION PATHWAYS; REACTIVITY; THIOLS; TRIFLUOROBUTANETHIOLS;

SULFUR COMPOUNDS;

EID: 0030567308     PISSN: 07437463     EISSN: None     Source Type: Journal    
DOI: 10.1021/la950363q     Document Type: Article

References (30)

1. Parker, B.; Gellman, A. J. Surf. Sci. 1993, 292, 223.
2. Jaffey, D. M.; Madix, R. M. Surf. Sci. 1994, 311, 159.
3. Dubois, L. H.; Zegarski, B. R.; Nuzzo, R. G. J. Chem. Phys. 1993, 98, 678.
4. Nuzzo, R. G.; Zegarski, B. R.; Dubois, L. H. J. Am. Chem. Soc. 1987, 109, 733.
5. Albert, M. R.; Lu, J. P.; Bernasek, S. L.; Cameron, S. D.; Gland, J. L. Surf. Sci. 1988, 206, 348.
6. Roberts, J. T.; Friend, C. M. J. Am. Chem. Soc. 1986, 108, 7204.
7. Roberts, J. T.; Friend, C. M. J. Phys. Chem. 1988, 92, 5205.
8. Huntley, D. R. J. Phys. Chem. 1989, 93, 6156.
9. Friend, C. M.; Roberts, J. T. Acct. Chem. Res. 1988, 21, 394.
10. Castro, M. E.; Ahkter, S.; Golchet, A.; White, J. M.; Sahin, T. Langmuir 1991, 7, 126.
11. Napier, M. E.; Friend, C. M. J. Phys. Chem. 1996, 99, 8750.
12. 6 no low-temperature (265 K) butene was observed. The absence of the low-temperature butene state was due to a high hydrogen background in the chamber used for the initial experiments and consequently a high surface hydrogen concentration. The initial results could be replicated in the current system by preadsorbing hydrogen or deuterium prior to the adsorption of butanethiol. As discussed in the text, preadsorption of hydrogen alters the product distribution, such that the hydrogenolysis product, butane, is favored.
13. Weldon, M. K.; Friend, C. M. Rev. Sci. Instrum. 1996, 66 (11), 5192.
14. Napier, M. E.; Friend, C. M. Unpublished results.
15. Weldon, M. K.; Friend, C. M. Surf. Sci. 1994, 310, 95.
16. Bain, C. D.; Troughton, E. B.; Tao, Y.; Evall, J.; Whitesides, G. M.; Nuzzo, R. G. J. Am. Chem. Soc. 1989, 111, 321.
17. Identification of 1,1,1-rifluorobutane was made by comparison to the mass fragmentation pattern obtained for trifluorobutane evolving from a hydrogen-presaturated surface (Table 1).
18. Roberts, J. T.; Friend, C. M. Surf. Sci. 1987, 186, 201.
19. Weldon, M. K.; Napier, M. E.; Wiegend, B. C.; Friend, C. M.; Uvdal, P. J. Am. Chem. Soc. 1994, 116, 8328.
20. Shown in Figure 3 are the relative yields of the three fluorocarbon products and hydrogen fluoride versus sulfur or thiolate coverage. The relative yields were calculated by dividing the peak height at each coverage by the maximum peak height observed for each species, giving a maximum relative yield of 1. The masses used to calculate the yields are as follows: mass 29 for trifluorobutane, mass 110 for trifluorobutene, mass 64 for difluoroethylene, and mass 20 for hydrogen fluoride. The error for each measurement is based on the calculation of one standard deviation for a minimum of five experiments.
21. Kuramshina, G. M.; Pentin, Y. A. J. Chem. Thermodyn. 1979, 11, 1115.
22. Forbes, J. G.; Gellman, A. J. J. Am. Chem. Soc. 1993, 115, 6277.
23. Orientation effects could, in principle, make the v(S-H) mode dipole forbidden and thus not observable in the IR. No other S-H modes were observed in the IR and the v(S-H) was not observed for any coverage up to saturation, even though the molecule reorients in this range. This suggests that the lack of a v(S-H) is not due to orientation.
24. CRC Handbook of Chemistry and Physics, 70th ed.; CRC Press, Iac.: Boca Raton, FL, 1990.
25. Lin, J. L.; Yates, J. T., Jr. J. Vac. Sci. Technol. A 1995, 13, 178.
26. Paul, A.; Gellman, A. J. Submitted for publication in Langmuir.
27. Street, S. C.; Gellman, A. J. Submitted for publication in J. Chem. Phys.
28. The difference in the irreversible decomposition pathways is based on a comparison of carbon Auger signals for ethane, butane, trifluoroethane, and trifluorobutanethiolate after reaction at equivalent coverages.
29. The heats of formation for the fluorinated thiol compounds are not available in the literature, so the bond additivity method was used to estimate these values.
30. JANAF Thermochemical Tables, 2nd ed.; Nat. Bur. Stand.: Gaithersburg, 1971.