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Reporter: Zhang Lei Supervisor: Prof. Mo Prof. Wang and Prof. Zhang Date: 2016-3-11. Outline. Introduction Recent Developments in CO2 Hydrogenation to Formate Formic Acid Dehydrogenation with Various Metal Complexes
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Reporter: Zhang Lei Supervisor: Prof. Mo Prof. Wang and Prof. Zhang Date: 2016-3-11
Outline • Introduction • Recent Developments in CO2 Hydrogenation to Formate • Formic Acid Dehydrogenation with Various Metal Complexes • Interconversion of CO2 and Formic Acid • Recent Developments in CO2 Hydrogenation to Methanol • Summary and Future Outlook
Outline • Introduction • Recent Developments in CO2 Hydrogenation to Formate • Formic Acid Dehydrogenation with Various Metal Complexes • Interconversion of CO2 and Formic Acid • Recent Developments in CO2 Hydrogenation to Methanol • Summary and Future Outlook
1.Introduction Climate change Rising sea levels High concentration of CO2 Utilization of CO2 Methods Photochemical CO2 reduction Electrochemical CO2 reduction CO2 hydrogenation Artificial photosynthesis Bulk electrolysis Using solar-produced H2 Reaction of metal oxides at extremely high temperature
1.Introduction • Photochemical CO2 reduction
1.Introduction • Photochemical CO2 reduction TON 17(24h) Sato, S. et al., J. Am. Chem. Soc. 2011, 133, 15240−15243.
1.Introduction • Photochemical CO2 reduction TON 41(9h) Sekizawa, K.; Ishitani, O. et al., J. Am. Chem. Soc. 2013, 135, 4596−4599.
1.Introduction • Limitations including: (i) low turnover numbers and low turnover frequencies (ii) product selectivity (i.e., CO, formate, H2,and other minor products); (iii) use of precious metal catalysts; (iv) use of organic solvents and sacrificial reagents; (v) controlling the pH; (vi) the requirement of coupling oxidative and reductivehalf-reactions. • Photochemical CO2 reduction
1.Introduction • Electrochemical CO2 reduction Main production is CO • CO2 hydrogenation Main aim: hydrogen storage Main production: HCOOH,CH3OH Thermal data:
1.Introduction • CO2 hydrogenation The thermal reduction
1.Introduction • CO2 hydrogenation to formate; • (2) Formic acid (FA) dehydrogenation; • (3) interconversion of CO2 and formic acid; • (4) CO2 hydrogenation to methanol.
2.CO2 Hydrogenation to Formate • 2.1. Catalysts with Phosphine Ligands • 2.2. Catalysts with Pincer Ligands • 2.3. Catalysts with N-Heterocyclic Carbene Ligands • 2.4. Half-Sandwich Catalysts with/without Proton-Responsive Ligands 2.4.1. Electronic Effects 2.4.2. Second-Coordination-Sphere Effects 2.4.3. Mechanistic Investigations 2.4.4. pH-Dependent Solubility and Catalyst Recovery
2.1. Catalysts with Phosphine Ligands • Pioneering work Inoue, Y. et al., Chem. Lett. 1976, 863−864. • Solvent effect Ezhova, N. N. et al., Russ. Chem. Bull. 2002, 51, 2165−2169.
2.1. Catalysts with Phosphine Ligands • The role of water NBD Tsai, J. C.; Nicholas, K. M. J. Am. Chem. Soc. 1992, 114,5117−5124.
2.1. Catalysts with Phosphine Ligands • Water-soluble catalysts Gassner, F.; Leitner, W. J. Chem. Soc.,Chem. Commun.1993, 1465−1466. • Mechanism 156 Horvath, H.; Laurenczy, G.; Katho, A. J. Organomet.Chem. 2004, 689, 1036−1045.
2.1. Catalysts with Phosphine Ligands • Nonprecious-metal catalysts Federsel, C.; Beller, M. et al., Chem. - Eur. J. 2012, 18, 72−75.
2.1. Catalysts with Phosphine Ligands • Combination of scCO2 and ionic liquid (IL) TON 1970, TOF 295/h Wesselbaum, S.; Hintermair, U.; Leitner, W. Angew. Chem., Int. Ed.2012, 51, 8585−8588.
2.1. Catalysts with Phosphine Ligands • Novel protocols TON 2800(20h) Xu, Z.; Hicks, J. C. et al., ChemCatChem2013, 5, 1769−1771.
2.2. Catalysts with Pincer Ligands Tanaka, R.; Nozaki, K. et al., J. Am. Chem. Soc. 2009, 131, 14168−14169.Tanaka, R.; Nozaki, K. et al., Organometallics. 2011, 30, 6742−6750.
2.2. Catalysts with Pincer Ligands Tanaka, R.; Nozaki, K. et al., Organometallics. 2011, 30, 6742−6750.
2.2. Catalysts with Pincer Ligands • Secondary coordination sphere interaction • proton-responsive ligands; (2) electro-responsive ligands; (3) ligands that can provide a hydrogen bonding functionality; (4) photoresponsive ligands that exhibit a useful change in properties upon irradiation; (5)NADH-type ligands that can work as a hydride source; (6)hemilabile ligands that provide a vacant coordination site.
2.2. Catalysts with Pincer Ligands • Hydrogen bonding functionality Schmeier, T. J.; Hazari, N. et al., J. Am. Chem. Soc. 2011, 133, 9274−9277.
2.2. Catalysts with Pincer Ligands • Nonprecious metals Langer, R.; Milstein, D. et al., Angew. Chem., Int. Ed.2011, 50, 9948−9952.
2.2. Catalysts with Pincer Ligands Filonenko, G. A.; Pidko, E. A. et al., ChemCatChem2014, 6, 1526−1530.
2.3. N-Heterocyclic Carbene Ligands Azua, A.; Sanz, S.; Peris, E. Chem. - Eur. J.2011, 17, 3963−3967. Sanz, S.; Benitez, M.; Peris, E. Organometallics2010, 29, 275−277.
2.4. Half-Sandwich Catalysts • Discovery [Cp*Rh(bpy)Cl]Cl transfer hydrogenation of ketones Himeda, Y. et al., J. Mol. Catal. A: Chem. 2003, 195, 95−100. • Electronic Effects
2.4. Half-Sandwich Catalysts • Electronic Effects Hammett constants (σp+): the more negative their σp+ value, the stronger is their ability to donate electrons.
2.4. Half-Sandwich Catalysts • Electronic Effects Himeda, Y. et al. Organometallics2007, 26, 702−712. Maenaka, Y.; Suenobu, T.; Fukuzumi, S. Energy Environ. Sci.2012, 5,7360−7367.
2.4. Half-Sandwich Catalysts • Second-Coordination-Sphere Effects
2.4. Half-Sandwich Catalysts • Second-Coordination-Sphere Effects
2.4. Half-Sandwich Catalysts • Second-Coordination-Sphere Effects Wang, W.-H.; Himeda, Y. et al., Energy Environ. Sci. 2012, 5, 7923−7926.
2.4. Half-Sandwich Catalysts • Mechanistic Investigations
2.4. Half-Sandwich Catalysts • Kinetic isotope effect (KIE) study [Cp*Ir(4DHBP)(OH2)]2+ D2 in KHCO3/H2O (KIE: 1.19) and in KDCO3/D2O (KIE: 1.20)solution. D2O in H2/KDCO3 (KIE: 0.98). [Cp*Ir(6DHBP)(OH2)]2+ D2O resulted in a larger rate decrease than with D2 (bearing pendant OH groups). RDS
2.4. Half-Sandwich Catalysts • pH-Dependent Solubility and Catalyst Recovery Himeda, Y. et al., Organometallics2007, 26, 702−712.
2.4. Half-Sandwich Catalysts • pH-Dependent Solubility and Catalyst Recovery
3. Formic Acid Dehydrogenation • 3.1. Catalysts with Phosphine Ligands 3.1.1. Organic Solvent Systems 3.1.2. Aqueous Solvent Systems • 3.2. Catalysts with Pincer-Type Ligands • 3.3. Catalysts with Bidentate C,N-/N,N-Ligands • 3.4. Half-Sandwich Catalysts with/without Proton-Responsive Ligands 3.4.1. Electronic Effects 3.4.2. Pendant-Base Effect Changing RDS of Formic Acid Dehydrogenation 3.4.3. Solution pH Changing RDS of Formic Acid Dehydrogenation • 3.5. Nonprecious Metals
3. Formic Acid Dehydrogenation • Thermal data:
3.1. Phosphine Ligands • Pioneering work Coffey, R. S. Chem. Commun. 1967, 923b. • The role of base Boddien, A.; Beller, M. et al., Adv. Synth. Catal. 2009, 351, 2517−2520.
3.1. Phosphine Ligands • Facially capping ligand Manca, G.; Beller, M.et al., Organometallics2013, 32, 7053−7064.
3.1. Phosphine Ligands • Facially capping ligand
3.1. Phosphine Ligands • Base-free FA dehydrogenation
3.1. Phosphine Ligands • Base-free FA dehydrogenation Oldenhof, S.; Reek, J. N. et al., Chem. - Eur. J. 2013, 19, 11507−11511.
3.1. Phosphine Ligands • Aqueous Solvent Systems Fellay, C.; Dyson, P. J.; Laurenczy, G. Angew. Chem., Int. Ed.2008, 47, 3966−3968.
3.2. Catalysts with Pincer-Type Ligands • Mechanism Vogt, M.; Milstein, D. Chem. Sci.2014, 5, 2043−2051.
3.3. Half-Sandwich Catalysts Barnard, J. H.; Xiao, J. Chem. Sci.2013, 4, 1234−1244.
3.4. Proton-Responsive Ligands • Electronic Effects
3.4. Proton-Responsive Ligands • Pendant-Base Effect Changing RDS of Formic Acid Dehydrogenation
3.4. Proton-Responsive Ligands • KIE studies With Proton-Responsive Ligands DCO2D replaces HCO2H--2, D2O replaces H2O--1 Without Proton-Responsive Ligands D2O in place of H2O—2.1 DCO2D instead of HCO2H --1.4 proton relay incorporating a H2O molecule proton relay incorporating a H2O molecule
3.4. Proton-Responsive Ligands • Solution pH Changing RDS of Formic Acid Dehydrogenation • KIE studies • pH 1.7 • DCO2D (KIE: 2.04) • D2O (KIE: 1.46) • pH 3.5 • D2O(KIE: 2.70) • DCO2D/DCO2Na(KIE: 1.48)
3.4. Proton-Responsive Ligands Wang, W.-H.; Himeda, Y. ACS Catal.2015, 5, 5496−5504.