Studies on the Nature of Catalysis: Suppression of the Catalytic Activity of Leached Pd by Supported Pd Particles during the Heck Reaction
Source abstract
Abstract
In the Heck coupling of bromobenzene and styrene over conventionally prepared Pd particles supported on SiO 2 at 135 °C under Ar with Na 2 CO 3 as the base, the catalysis of 2−4 ppm of leached Pd in solution is considerably affected by the supported Pd particles. Although such low concentration leached Pd alone is very active for the Heck reaction, its catalytic activity is suppressed in the presence of the supported Pd particles. Despite this, the variation of TON with leached Pd concentration follows the same trend of a homogeneous Pd catalyst. Homogeneous catalysis in nature is suggested based on the fact that the solid−liquid reaction rate is dependent on the leached Pd concentration rather than the supported Pd loading. The change of homogeneous catalysis relating to the variation of active Pd fraction in the presence and absence of the supported Pd particles is discussed.
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Research context
OpenAlex topics: Catalytic Cross-Coupling Reactions · Nanomaterials for catalytic reactions · Ammonia Synthesis and Nitrogen Reduction
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research, 1 Pesek Road, Jurong Island, Singapore 627833, Singapore
References (29)
Show source-provided references
1. Beletskaya I. P. · Chem. Rev. · 2000 · 100 · 300910.1021/cr9903048 ↗
2. Littke A. F. · Angew. Chem., Int. Ed. · 2002 · 41 · 417610.1002/1521-3773(20021115)41:22<4176::AID-ANIE4176>3.0.CO;2-U ↗
3. Bräse, S.; de Meijere, A.InMetal-Catalyzed Cross-Coupling Reactions, 2nd ed.de Meijere, A.; Diederich, F., Eds.Wiley-VCH:Weinheim, Germany, 2004; p217.10.1002/9783527619535 ↗
4. Trzeciak A. M. · Coord. Chem. Rev. · 2007 · 251 · 128110.1016/j.ccr.2006.11.013 ↗
5. Polshettiwar V. · Tetrahedron · 2007 · 63 · 694910.1016/j.tet.2007.04.023 ↗
6. Reetz M. T. · Chem. Commun. · 2004 · 155910.1039/b406719n ↗
7. Farina V. · Adv. Synth. Catal. · 2004 · 346 · 155310.1002/adsc.200404178 ↗
8. Yin L. · Chem. Rev. · 2007 · 107 · 13310.1021/cr0505674 ↗
9. Biffis A. · J. Mol. Catal. A · 2001 · 173 · 24910.1016/S1381-1169(01)00153-4 ↗
10. Phan N. T. S. · Adv. Synth. Catal. · 2006 · 348 · 60910.1002/adsc.200505473 ↗
11. Huang L. · Catal. Lett. · 2006 · 112 · 21910.1007/s10562-006-0206-8 ↗
12. Demel J. · J. Mol. Catal. A · 2007 · 274 · 12710.1016/j.molcata.2007.05.001 ↗
13. Barau A. · Catal. Lett. · 2008 · 124 · 20410.1007/s10562-008-9465-x ↗
14. Wang P. · Microporous Mesoporous Mater. · 2008 · 116 · 40010.1016/j.micromeso.2008.04.029 ↗
15. Jana S. · Inorg. Chem. · 2008 · 47 · 551210.1021/ic8004294 ↗
16. Davies I. W. · J. Am. Chem. Soc. · 2001 · 123 · 1013910.1021/ja016877v ↗
17. Dams M. · J. Catal. · 2002 · 209 · 22510.1006/jcat.2002.3630 ↗
18. Caporusso A. M. · J. Catal. · 2005 · 234 · 110.1016/j.jcat.2005.05.008 ↗
19. Richardson J. M. · Adv. Synth. Catal. · 2006 · 348 · 120710.1002/adsc.200606021 ↗
20. Zhao F. · Chem.—Eur. J. · 2000 · 6 · 84310.1002/(SICI)1521-3765(20000303)6:5<843::AID-CHEM843>3.0.CO;2-G ↗
21. Biffis A. · Eur. J. Inorg. Chem. · 2001 · 113110.1002/1099-0682(200105)2001:5<1131::AID-EJIC1131>3.0.CO;2-3 ↗
22. Köhler K. · Chem.—Eur. J. · 2002 · 8 · 62210.1002/1521-3765(20020201)8:3<622::AID-CHEM622>3.0.CO;2-0 ↗
23. Pröckl S. S. · Tetrahedron · 2005 · 61 · 985510.1016/j.tet.2005.06.111 ↗
24. Thathagar M. B. · Angew. Chem., Int. Ed. · 2006 · 45 · 288610.1002/anie.200504321 ↗
25. We attempted to test the catalysis homogeneity or heterogeneity in the Heck coupling of PhBr and styrene over Pd0/SiO2at 135 °C under Ar, using efficient metal scavengers as selective poisons for leached homogeneous Pd. Although the catalysis can be effectively quenched by adding these metal scavengers during the Heck reaction, our catalytic tests and elemental analysis demonstrate thatsignificant amounts of thiol groups are dissociated from the scavengers under operating reaction conditions so as to interact with Pd particles supported on SiO2as well as forming thiol-coordinated Pd (see theSupporting Information). In these circumstances, both the supported Pd particles and the leached homogeneous Pd are poisoned by thiol ligands after addition of the scavengers, which indicates the inappropriateness of catalyst poisoning with such scavengers under such reaction conditions for identifying the nature of catalysis.
26. Zhan F. · J. Mol. Catal. A · 2002 · 180 · 21110.1016/S1381-1169(01)00436-8 ↗
27. De Vries A. H. M. · Org. Lett. · 2003 · 5 · 328510.1021/ol035184b ↗
28. De Vries J. G. · Dalton Trans. · 2006 · 42110.1039/B506276B ↗
29. Zhao F. · J. Catal. · 2000 · 194 · 47910.1006/jcat.2000.2934 ↗