Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols...
Transcript of Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols...
![Page 1: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/1.jpg)
Discovery of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and
Amido Rh Complexes
Chathurika Ruwanthi Jayasundara Michigan State University
Chemistry Department 1
![Page 2: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/2.jpg)
Dehydrogenation/Oxidation by Conventional Oxidants
Gunanathan, C.; Milstein, D. Science 2013, 341 , 249-260. 2
Jones Oxidation
Classes of Dehydrogenation Reaction
![Page 3: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/3.jpg)
Hydrogen Transfer Reaction
Gunanathan, C.; Milstein, D. Science 2013, 341, 249-260. 3
Oppenauer Oxidation (Meerwein-Ponndorf-Verley reduction)
Classes of Dehydrogenation Reaction
![Page 4: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/4.jpg)
Classes of Dehydrogenation Reaction
Gunanathan, C.; Milstein, D. Science 2013, 341, 249-260. 4
Hydrogen transfer reaction
![Page 5: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/5.jpg)
5
Dehydrogenation Reactions Catalyzed by Rh(I) Amido Complex
Zweifel, T.; Naubron, J. V.; Grutzmacher, H. Angew Chem Int Edit 2009, 48 , 559-563.
Grützmacher and Co-workers
catalyst MTCA+Cl- = methyltricapryl ammonium chloride
![Page 6: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/6.jpg)
Rhodium(I) Amido Complex
Zweifel, T.; Naubron, J. V.; Buttner, T.; Ott, T.; Grutzmacher, H. Angew Chem Int Edit 2008, 47 , 3245-3249. Trincado, M.; Grutzmacher, H.; Vizza, F.; Bianchini, C., Chem-Eur J 2010, 16 , 2751-2757. Buttner, T.; Breher, F.; Grutzmacher, H., Chem Commun 2004, , 2820-2821.
6
No heterolytical H2 splitting
![Page 7: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/7.jpg)
Rhodium(I) Amido Complex
Zweifel, T.; Naubron, J. V.; Buttner, T.; Ott, T.; Grutzmacher, H. Angew Chem Int Edit 2008, 47 , 3245-3249. Trincado, M.; Grutzmacher, H.; Vizza, F.; Bianchini, C., Chem-Eur J 2010, 16, 2751-2757. Buttner, T.; Breher, F.; Grutzmacher, H., Chem Commun 2004, 2820-2821.
7
Unstable but split H2 heterolytically
Pre-catalyst
![Page 8: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/8.jpg)
Maire, P.; Buttner, T.; Breher, F.; Le Floch, P.; Grutzmacher, H. Angew Chem Int Edit 2005, 44, 6318-6323. Zweifel, T.; Naubron, J. V.; Buttner, T.; Ott, T.; Grutzmacher, H., Angew Chem Int Edit 2008, 47, 3245-3249.
8
Hydrogenation Catalyzed by Rh(I) Amide Complex
![Page 9: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/9.jpg)
Heterolytic and Oxidative Addition of H2 with Rh(I) Amide Complex
Maire, P.; Buttner, T.; Breher, F.; Le Floch, P.; Grutzmacher, H. Angew Chem Int Edit 2005, 44, 6318-6323.
9
[Rh(Cht2N)PH3] cht = cycloheptatrienyl
![Page 10: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/10.jpg)
Computed Frontier Orbital Diagram
Maire, P.; Buttner, T.; Breher, F.; Le Floch, P.; Grutzmacher, H. Angew Chem Int Edit 2005, 44, 6318-6323.
10
[Rh(Cht2N)PH3] cht = cycloheptatrienyl
![Page 11: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/11.jpg)
Maire, P.; Buttner, T.; Breher, F.; Le Floch, P.; Grutzmacher, H. Angew Chem Int Edit 2005, 44, 6318-6323. Zweifel, T.; Naubron, J. V.; Buttner, T.; Ott, T.; Grutzmacher, H. Angew Chem Int Edit 2008, 47, 3245-3249.
11
Hydrogenation Catalyzed by Rh(I) Amide Complex
![Page 12: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/12.jpg)
12
Dehydrogenation Reactions Catalyzed by Rh(I) Amido Complex
Zweifel, T.; Naubron, J. V.; Grutzmacher, H.,Angew Chem Int Edit 2009, 48 (3), 559-563.
Grützmacher and Co-workers
catalyst
![Page 13: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/13.jpg)
Zweifel, T.; Naubron, J. V.; Grutzmacher, H.,Angew Chem Int Edit 2009, 48 (3), 559-563.
13
Dehydrogenative coupling of primary alcohols
![Page 14: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/14.jpg)
Zweifel, T.; Naubron, J. V.; Grutzmacher, H.,Angew Chem Int Edit 2009, 48 (3), 559-563.
14
Simplified Catalytic Cycle
![Page 15: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/15.jpg)
15 Zweifel, T.; Naubron, J. V.; Grutzmacher, H. Angew Chem Int Edit 2009, 48 , 559-563.
Conversion of Ethanol and Water to Acetic Acid
![Page 16: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/16.jpg)
16 Zweifel, T.; Naubron, J. V.; Grutzmacher, H. Angew Chem Int Edit 2009, 48, 559-563.
Conversion of Ethanol and Water
to Acetic Acid
![Page 17: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/17.jpg)
17 Zweifel, T.; Naubron, J. V.; Grutzmacher, H.Angew Chem Int Edit 2009, 48, 559-563.
Conversion of Ethanol and Water
to Acetic Acid
![Page 18: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/18.jpg)
Zweifel, T.; Naubron, J. V.; Grutzmacher, H.,Angew Chem Int Edit 2009, 48 (3), 559-563.
18
Dehydrogenative coupling of primary alcohols
![Page 19: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/19.jpg)
Pros and Cons
19
Pros :
• Mild reaction conditions.
• Low catalytic loading(0.1 mol%)
• Functional group tolerance.
• Chemeoselectivity.
Cons : • Rh is an expensive metal.
• Formation of salt.
• Using a hydrogen acceptor.
Zweifel, T.; Naubron, J. V.; Grutzmacher, H.,Angew Chem Int Edit 2009, 48 (3), 559-563.
![Page 20: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/20.jpg)
Classes of Dehydrogenation Reaction
Gunanathan, C.; Milstein, D., Science 2013, 341 (6143), 249-260. 20
Dehydrogenation/Oxidation by Conventional Oxidants
Hydrogen Transfer Reaction
Acceptorless Dehydrogenation Leads to Liberation of H2
![Page 21: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/21.jpg)
21 Dobson, A.; Robinson, S. D., J Organomet Chem 1975, 87 , C52-C53. Blum, Y.; Shvo, Y., J Organomet Chem 1985, 282 , C7-C10. Inorganic Chemistry, Vol. 16, No. I , I977
1975 Robinson catalyst
1985 Shvo catalyst
Dehydrogenation of Primary and Secondary Alcohols
![Page 22: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/22.jpg)
Dehydrogenation of Primary and Secondary Alcohols
22
2005-2013
• Low catalytic loading
• H2 as the only byproduct
• Higher yields and turnover numbers
• Broad substrate scopes and mild reaction conditions
• Atom economy
• Mechanistic studies
“After initial studies more than 30 years ago this method remains strongly neglected” -Friedrich, A.; Schneider, S., Chemcatchem 2009, 1 (1), 72-73.
Milstein and coworkers: - reported unprecedented dehydrocoupling of alcohols to acetals in high yield This lead to finding of environmentally benign reactions.
Zhang, J.; Leitus, G.; Ben-David, Y.; Milstein, D., J Am Chem Soc 2005, 127 , 12429-12429. Friedrich, A.; Schneider, S., Chemcatchem 2009, 1, 72-73.
![Page 23: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/23.jpg)
Acceptorless Reactions Catalyzed by Ru Pincer Complexes
Balaraman, E.; Khaskin, E.; Leitus, G.; Milstein, D., Nat Chem 2013, 5, 122-125. Gunanathan, C.; Milstein, D. Science 2013, 341, 249-260.
23
![Page 24: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/24.jpg)
• Is a type of chelating ligand that binds tightly on a transition metal using three adjacent sites.
• Properties:
• Extraordinary thermal stability. • high melting points. • Hemi labile property.
Pincer Ligands
Morales-Morales, D. Mini-Rev Org Chem 2008, 5, 141-152. 24
![Page 25: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/25.jpg)
Dehydrogenative Coupling of Alcohols to Esters
Zhang, J.; Leitus, G.; Ben-David, Y.; Milstein, D. J Am Chem Soc 2005, 127, 10840-10841. 25
![Page 26: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/26.jpg)
Dehydrogenative Coupling of Alcohols to Esters
26 Zhang, J.; Leitus, G.; Ben-David, Y.; Milstein, D. J Am Chem Soc 2005, 127, 10840-10841.
![Page 27: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/27.jpg)
Alcohols to Esters Without KOH
Zhang, J.; Leitus, G.; Ben-David, Y.; Milstein, D. J Am Chem Soc 2005, 127 , 10840-10841. 27
![Page 28: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/28.jpg)
Dehydrogenative Coupling of Alcohols to Esters
28 Zhang, J.; Leitus, G.; Ben-David, Y.; Milstein, D., J Am Chem Soc 2005, 127 (35), 10840-10841.
Overall reaction scheme
![Page 29: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/29.jpg)
Plausible Mechanism for Ester Synthesis
29 Zhang, J.; Leitus, G.; Ben-David, Y.; Milstein, D., J Am Chem Soc 2005, 127, 10840-10841. Milstein, D., Top Catal 2010, 53 , 915-923
![Page 30: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/30.jpg)
Hemilabile Ligands
30 Braunstein, P.; Naud, F. Angew Chem Int Edit 2001, 40 (4), 680-699.
• Hybrid ligands contain at least two different types of chemical functionality capable of binding to metal centers.
• Functionalities are chosen to be very different from each other to increase the differentiation between their resulting interactions with the metal center.
• Achieved by combining hard and soft donors in the same ligand.
• Hemilabile ligands have at least one labile donor function Z while the other donor group(s) D remain firmly bound to the metal center.
![Page 31: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/31.jpg)
Aromatization and Dearomatization of The PNN Ligand
Yang, X. Z.; Hall, M. B. J Am Chem Soc 2010, 132 , 120-130. Sacco, A.; Vasapollo, G.; Nobile, C. F.; Piergiovanni, A.; Pellinghelli, M. A.; Lanfranchi, M. J Organomet Chem 1988, 356 , 397-409.
31
Calculated relative gas-phase electronic energies (kcal/mol)
![Page 32: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/32.jpg)
Proposed Mechanism for The Direct Acylation of Amines
32 . Gunanathan, C.; Ben-David, Y.; Milstein, D. Science 2007, 317, 790-792.
![Page 33: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/33.jpg)
Dehydrogenative Coupling of Alcohols to Amides
33
b= The remaining alcohol was converted into corresponding ester.
Gunanathan, C.; Ben-David, Y.; Milstein, D. Science 2007, 317, 790-792.
![Page 34: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/34.jpg)
Proposed Mechanism for The Direct Acylation of Amines
34 . Gunanathan, C.; Ben-David, Y.; Milstein, D. Science 2007, 317, 790-792.
![Page 35: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/35.jpg)
Different Mechanism for Amide Synthesis
35 . Gunanathan, C.; Ben-David, Y.; Milstein, D. Science 2007, 317, 790-792.
![Page 36: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/36.jpg)
36 Balaraman, E.; Khaskin, E.; Leitus, G.; Milstein, D. Nat Chem 2013, 5, 122-125.
Catalytic Transformation of Alcohols to Carboxylic Acid Salts and H2
![Page 37: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/37.jpg)
37 Balaraman, E.; Khaskin, E.; Leitus, G.; Milstein, D., Nat Chem 2013, 5 (2), 122-125.
?
“The PNN complex also catalyzes this reaction, but less efficiently. The reason for that is not clear at this stage” - Prof. David Milstein
Catalytic Transformation of Alcohols to Carboxylic Acid Salts and H2
![Page 38: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/38.jpg)
Hydrogenation of Double Bonds
38 Balaraman, E.; Khaskin, E.; Leitus, G.; Milstein, D. Nat Chem 2013, 5, 122-125.
![Page 39: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/39.jpg)
Proposed Mechanism for Formation of Carboxylate From Alcohol
Balaraman, E.; Khaskin, E.; Leitus, G.; Milstein, D., Nat Chem 2013, 5 (2), 122-125.
39
![Page 40: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/40.jpg)
40
Relative Enthalpies for Alcohol to Carboxylic Acid Transformation
Balaraman, E.; Khaskin, E.; Leitus, G.; Milstein, D., Nat Chem 2013, 5 (2), 122-125.
![Page 41: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/41.jpg)
Balaraman, E.; Khaskin, E.; Leitus, G.; Milstein, D., Nat Chem 2013, 5 (2), 122-125.
41
Carboxylic Acid-Addition Complex
![Page 42: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/42.jpg)
Pros and Cons
42
Pyridine based Ru pincer complexes • Acceptorless dehydrogenation of
alcohol • Higher atom economy • Low catalytic loading (0.1-0.3 mol%) • H2 gas as the only byproduct • Chemeoselectivity • Good yields and turnover numbers • At high pH no aldol products Cons • Salt production • Metal and ligand are expensive
Conventional methods • Stoichiometric amount of
oxidant • Give rise to stoichiometric
amount of waste, with toxic metals
• Less atom economy
Previous catalytic systems • High catalytic loading (1-
5 mol%) • Strong acid or base
conditions • Less turnover numbers
Balaraman, E.; Khaskin, E.; Leitus, G.; Milstein, D., Nat Chem 2013, 5 (2), 122-125. Gunanathan, C.; Ben-David, Y.; Milstein, D., Science 2007
![Page 43: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/43.jpg)
Advancing From Py Based Ru Pincer Complexes to Iron Pincer Complexes
43 Langer, R.; Leitus, G.; Ben-David, Y.; Milstein, D., Angew Chem Int Edit 2011, 50 (9), 2120-2124.
![Page 44: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/44.jpg)
Advancing From Py Based Ru Pincer Complexes to Iron Pincer Complexes
44 Langer, R.; Leitus, G.; Ben-David, Y.; Milstein, D. Angew Chem Int Edit 2011, 50, 2120-2124.
![Page 45: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/45.jpg)
Hydrogenation of Ketones by Iron Pincer Complex
45 Langer, R.; Leitus, G.; Ben-David, Y.; Milstein, D. Angew Chem Int Edit 2011, 50 , 2120-2124.
![Page 46: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/46.jpg)
“An important goal yet to be achieved”
46
-Zweifel, T.; Naubron, J. V.; Grutzmacher, H.,Angew Chem Int Edit 2009, 48 (3), 559-563.
![Page 47: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/47.jpg)
47
Acknowledgement
• Dr. Maleczka
• Dr. Huang
• Dr Jackson, Dr. Mitch
• Salinda and Dilini
• All my group members
• Behnaz, Dmitrijs, Souful, Tayeb, Yu-Ling, Tim, Buddhadeb
• All my friends
![Page 48: Discovery of Environmentally Benign Reactions of … of Environmentally Benign Reactions of Alcohols Catalyzed by Pyridine-Based Pincer Ru and Amido Rh Complexes Chathurika Ruwanthi](https://reader035.fdocuments.net/reader035/viewer/2022062413/5adc908a7f8b9a1a088c236c/html5/thumbnails/48.jpg)
48