Impact of molecular order in Langmuir-Blodgett films on catalysis

Science

Volumn 278, Issue 5346, 1997, Pages 2100-2102

  Töllner, Karl ^a   Popovitz Biro, Ronit ^a   Lahav, Meir ^a   Milstein, David ^a  

^a WEIZMANN INSTITUTE OF SCIENCE   (Israel)

Author keywords

[No Author keywords available]

Indexed keywords

METAL COMPLEX; RHODIUM COMPLEX;

ARTICLE; CATALYSIS; COMPLEX FORMATION; HYDROGENATION; MOLECULAR INTERACTION; MOLECULAR RECOGNITION; PRIORITY JOURNAL;

EID: 0037973227     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.278.5346.2100     Document Type: Article

References (19)

1. G. W. Parshall and S. D. Ittel, Homogeneous Catalysis (Wiley, New York, ed. 2, 1992).
2. For an overview, see A. Ulman, Thin Films, Organic Thin Films and Surfaces: Directions for the Nineties (Academic Press, New York, 1995), vol. 20;
3. and J. L. Atwood, J. E. D. Davies, D. D. MacNicol, F. Vögtle, Comprehensive Supramolecular Chemistry Templating Self-Assembly and Self-Organisation (Pergamon, New York, 1996), vol. 9.
4. M. G. L. Petrucci and A. K. Kakkar, Adv. Mater. 8, 251 (1996);
5. J. Chem. Soc. Chem. Commun. 1995, 1577 (1995).
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7. The ligand 4,4′-diheptadecyl-2,2′-bipyridine was prepared by double lithiation of 4,4′-dimethyl-2,2′-bipyridine, followed by reaction with 1-bromohexadecane [D. K. Ellison and R. T. Iwamato, Tetrahedron Lett. 24, 31 (1983)].
8. The tail-to-glass oriented layers are stable only under water. When the slide is taken out through a compressed monolayer on the water surface, an additional layer is deposited, whereas without a monolayer (or with an uncompressed one) the transferred layer peels off. We solved this problem by handling the tail-to-glass loaded slides permanently under water. After the last layer transfer the slides were lowered into a prearranged vial, which served as the reaction container.
9. -1 [R. A. Deuhy and D. G. Cornell, in Fourier Transform Spectroscopy in Colloid and Interface Science, D. R. Scheiung, Ed. (ACS Symposium Series, Washington, DC, 1990), vol. 447, p. 192].
10. 2) glass slide. This vial was then transferred to a 90-ml Fisher-Porter type pressure flask. The flask was pressurized with 72 psi of hydrogen and allowed to react at room temperature for 48 hours without stirring. The solution was analyzed by GC and GC-MS.
11. 2), the area on the slides covered with catalyst (measured for each transfer), and the amount of isopropanol formed (as detected by GC).
12. Complex 1 was inactive in both normal (hydrophilic) as well as hydrophobized reaction vessels. Hydrophobized reaction vessels were used to eliminate the possibility of the complex forming a head-to-glass layer on the walls of the vessel.
13. R. Popovitz-Biro et al., J. Am. Chem. Soc. 116, 1179 (1994).
14. 2; total volume, 35 ml) that were filled with 2 ml of a 100 mM aqueous acetone solution. The monolayer was spread on the water surface by applying with a syringe 2.6 μl from a 615 mM solution of complex 1 in methylene chloride. This amount was calculated to form a dense but uncompressed monolayer on the surface.
15. The turnover numbers after 48 hours (500 for acetone, 300 for butanone) are in accord with the different reactivity of the two ketones as reported in (4).
16. In addition to ethanol, the cyclic aldehyde trimer and acetic acid were also detected.
17. D. Jacquemain et al., Angew. Chem. Int. Ed. Engl. 1,130 (1992), and references therein.
18. xy range of the Bragg peak. For further information, see J. Als-Nielsen et al., Phys. Rep. 246, 251 (1994).
19. We thank I. Weissbuch for discussions and the grazing incidence x-ray diffraction measurements performed at Deutschen Electronen-Synchrotron at Hamburger Synchrotronstrahlungslabor. K.T. thanks the Minerva Foundation, Munich, Germany, for a fellowship. K.T. and D.M. thank the Israel Science Foundation, Jerusalem, Israel, for financial support. M.L. thanks the German-Israeli Foundation for financial support.