51
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Steinlechner C, Junge H. Renewable Methane Generation from Carbon Dioxide and Sunlight. Angew Chem Int Ed Engl 2017; 57:44-45. [DOI: 10.1002/anie.201709032] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Indexed: 11/09/2022]
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52
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Steinlechner C, Junge H. Nachhaltige Produktion von Methan aus CO2
mithilfe von Sonnenlicht. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201709032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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53
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Giereth R, Frey W, Junge H, Tschierlei S, Karnahl M. Copper Photosensitizers Containing P^N Ligands and Their Influence on Photoactivity and Stability. Chemistry 2017; 23:17432-17437. [PMID: 29024115 DOI: 10.1002/chem.201703672] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Indexed: 11/09/2022]
Abstract
Driven by the intention to improve classic heteroleptic copper photosensitizers two novel Cu(I) complexes applying a hetero-bidentate P^N ligand were prepared. A combined photophysical, electrochemical, and theoretical study gives insights into structure-activity relationships and revealed an increased absorptivity. Both complexes were tested for the light-driven production of H2 .
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54
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Sordakis K, Tang C, Vogt LK, Junge H, Dyson PJ, Beller M, Laurenczy G. Homogeneous Catalysis for Sustainable Hydrogen Storage in Formic Acid and Alcohols. Chem Rev 2017; 118:372-433. [DOI: 10.1021/acs.chemrev.7b00182] [Citation(s) in RCA: 608] [Impact Index Per Article: 86.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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55
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Prichatz C, Alberico E, Baumann W, Junge H, Beller M. Iridium-PNP Pincer Complexes for Methanol Dehydrogenation at Low Base Concentration. ChemCatChem 2017. [DOI: 10.1002/cctc.201700015] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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56
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Papa V, Cabrero-Antonino JR, Alberico E, Spanneberg A, Junge K, Junge H, Beller M. Efficient and selective hydrogenation of amides to alcohols and amines using a well-defined manganese-PNN pincer complex. Chem Sci 2017; 8:3576-3585. [PMID: 30155202 PMCID: PMC6092716 DOI: 10.1039/c7sc00138j] [Citation(s) in RCA: 144] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 02/24/2017] [Indexed: 12/23/2022] Open
Abstract
Novel well-defined NNP and PNP manganese pincer complexes have been synthetized and fully characterized. The catalyst Mn-2 containing an imidazolyaminolphosphino ligand shows high activity and selectivity in the hydrogenation of a wide range of secondary and tertiary amides to the corresponding alcohols and amines, under relatively mild conditions. For the first time, more challenging substrates like primary aromatic amides including an actual herbicide can also be hydrogenated using this earth-abundant metal-based pincer catalyst.
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57
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Chen NY, Xia LM, Lennox AJJ, Sun YY, Chen H, Jin HM, Junge H, Wu QA, Jia JH, Beller M, Luo SP. Structure-Activated Copper Photosensitisers for Photocatalytic Water Reduction. Chemistry 2017; 23:3631-3636. [DOI: 10.1002/chem.201602598] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 11/27/2016] [Indexed: 11/08/2022]
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58
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Priebe JB, Radnik J, Kreyenschulte C, Lennox AJJ, Junge H, Beller M, Brückner A. H2Generation with (Mixed) Plasmonic Cu/Au-TiO2Photocatalysts: Structure-Reactivity Relationships Assessed by in situ Spectroscopy. ChemCatChem 2017. [DOI: 10.1002/cctc.201601361] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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59
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Tschierlei S, Neubauer A, Rockstroh N, Karnahl M, Schwarzbach P, Junge H, Beller M, Lochbrunner S. Ultrafast excited state dynamics of iridium(III) complexes and their changes upon immobilisation onto titanium dioxide layers. Phys Chem Chem Phys 2017; 18:10682-7. [PMID: 27006105 DOI: 10.1039/c6cp00343e] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Time-resolved spectroscopy was applied to investigate the excited state dynamics of two heteroleptic Ir(III) complexes with the general formula [Ir(C^N)2(N^N)](+), where C^N and N^N represent different cyclometalating and diimine ligands, respectively. The excited state relaxation is influenced by the ligand substitution as well as the light polarisation. Vibrational relaxation occurs in the sub-ps timescale and interligand charge transfer results in polarisation dependent signal dynamics with a time constant of about 30 ps. Electron injection from the iridium dye to TiO2 is analysed with respect to potential applications in solar energy conversion.
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60
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Heberle M, Tschierlei S, Rockstroh N, Ringenberg M, Frey W, Junge H, Beller M, Lochbrunner S, Karnahl M. Inside Cover: Heteroleptic Copper Photosensitizers: Why an Extended π-System Does Not Automatically Lead to Enhanced Hydrogen Production (Chem. Eur. J. 2/2017). Chemistry 2017. [DOI: 10.1002/chem.201605126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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61
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Strobel V, Schuster JJ, Braeuer AS, Vogt LK, Junge H, Haumann M. Shining light on low-temperature methanol aqueous-phase reforming using homogeneous Ru-pincer complexes – operando Raman-GC studies. REACT CHEM ENG 2017. [DOI: 10.1039/c6re00228e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A combination of operando Raman spectroscopy with online GC and volume-flow monitoring allows rapid insight into low-temperature methanol reforming.
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62
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Rosas-Hernández A, Junge H, Beller M, Roemelt M, Francke R. Cyclopentadienone iron complexes as efficient and selective catalysts for the electroreduction of CO2 to CO. Catal Sci Technol 2017. [DOI: 10.1039/c6cy02352e] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Robust and easy-to-synthesize cyclopentadienone iron(0) complexes selectively catalyze the electrochemical conversion of CO2 to CO. Cooperation between the metal center and the coordinated organic ligand is a key factor for activity of these novel electrocatalysts.
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63
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Uddin MT, Nicolas Y, Olivier C, Jaegermann W, Rockstroh N, Junge H, Toupance T. Band alignment investigations of heterostructure NiO/TiO2 nanomaterials used as efficient heterojunction earth-abundant metal oxide photocatalysts for hydrogen production. Phys Chem Chem Phys 2017; 19:19279-19288. [DOI: 10.1039/c7cp01300k] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Earth-abundant NiO/TiO2 heterostructures lead to enhanced H2 production by methanol photoreforming due to favorable band bending at the interface of the NiO/anatase TiO2 p–n heterojunction.
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64
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Andérez-Fernández M, Vogt LK, Fischer S, Zhou W, Jiao H, Garbe M, Elangovan S, Junge K, Junge H, Ludwig R, Beller M. A Stable Manganese Pincer Catalyst for the Selective Dehydrogenation of Methanol. Angew Chem Int Ed Engl 2016; 56:559-562. [PMID: 27910197 PMCID: PMC6586016 DOI: 10.1002/anie.201610182] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Indexed: 12/14/2022]
Abstract
For the first time, structurally defined manganese pincer complexes catalyze the dehydrogenation of aqueous methanol to hydrogen and carbon dioxide, which is a transformation of interest with regard to the implementation of a hydrogen and methanol economy. Excellent long-term stability was demonstrated for the Mn-PNPiPr catalyst, as a turnover of more than 20 000 was reached. In addition to methanol, other important hydrogen carriers were also successfully dehydrogenated.
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65
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Andérez-Fernández M, Vogt LK, Fischer S, Zhou W, Jiao H, Garbe M, Elangovan S, Junge K, Junge H, Ludwig R, Beller M. A Stable Manganese Pincer Catalyst for the Selective Dehydrogenation of Methanol. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201610182] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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66
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Heberle M, Tschierlei S, Rockstroh N, Ringenberg M, Frey W, Junge H, Beller M, Lochbrunner S, Karnahl M. Heteroleptic Copper Photosensitizers: Why an Extended π-System Does Not Automatically Lead to Enhanced Hydrogen Production. Chemistry 2016; 23:312-319. [DOI: 10.1002/chem.201604005] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Indexed: 11/10/2022]
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67
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Alberico E, Lennox AJJ, Vogt LK, Jiao H, Baumann W, Drexler HJ, Nielsen M, Spannenberg A, Checinski MP, Junge H, Beller M. Unravelling the Mechanism of Basic Aqueous Methanol Dehydrogenation Catalyzed by Ru-PNP Pincer Complexes. J Am Chem Soc 2016; 138:14890-14904. [PMID: 27759392 DOI: 10.1021/jacs.6b05692] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Ruthenium PNP complex 1a (RuH(CO)Cl(HN(C2H4Pi-Pr2)2)) represents a state-of-the-art catalyst for low-temperature (<100 °C) aqueous methanol dehydrogenation to H2 and CO2. Herein, we describe an investigation that combines experiment, spectroscopy, and theory to provide a mechanistic rationale for this process. During catalysis, the presence of two anionic resting states was revealed, Ru-dihydride (3-) and Ru-monohydride (4-) that are deprotonated at nitrogen in the pincer ligand backbone. DFT calculations showed that O- and CH- coordination modes of methoxide to ruthenium compete, and form complexes 4- and 3-, respectively. Not only does the reaction rate increase with increasing KOH, but the ratio of 3-/4- increases, demonstrating that the "inner-sphere" C-H cleavage, via C-H coordination of methoxide to Ru, is promoted by base. Protonation of 3- liberates H2 gas and formaldehyde, the latter of which is rapidly consumed by KOH to give the corresponding gem-diolate and provides the overall driving force for the reaction. Full MeOH reforming is achieved through the corresponding steps that start from the gem-diolate and formate. Theoretical studies into the mechanism of the catalyst Me-1a (N-methylated 1a) revealed that C-H coordination to Ru sets-up C-H cleavage and hydride delivery; a process that is also promoted by base, as observed experimentally. However, in this case, Ru-dihydride Me-3 is much more stable to protonation and can even be observed under neutral conditions. The greater stability of Me-3 rationalizes the lower rates of Me-1a compared to 1a, and also explains why the reaction rate then drops with increasing KOH concentration.
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68
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Sun YY, Wang H, Chen NY, Lennox AJJ, Friedrich A, Xia LM, Lochbrunner S, Junge H, Beller M, Zhou S, Luo SP. Efficient Photocatalytic Water Reduction Using In Situ Generated Knölker's Iron Complexes. ChemCatChem 2016. [DOI: 10.1002/cctc.201600186] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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69
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Cabrero-Antonino JR, Alberico E, Junge K, Junge H, Beller M. Towards a general ruthenium-catalyzed hydrogenation of secondary and tertiary amides to amines. Chem Sci 2016; 7:3432-3442. [PMID: 29997838 PMCID: PMC6006866 DOI: 10.1039/c5sc04671h] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 02/08/2016] [Indexed: 11/21/2022] Open
Abstract
A broad range of secondary and tertiary amides has been hydrogenated to the corresponding amines under mild conditions using an in situ catalyst generated by combining [Ru(acac)3], 1,1,1-tris(diphenylphosphinomethyl)ethane (Triphos) and Yb(OTf)3. The presence of the metal triflate allows to mitigate reaction conditions compared to previous reports thus improving yields and selectivities in the desired amines. The excellent isolated yields of two scale-up experiments corroborate the feasibility of the reaction protocol. Control experiments indicate that, after the initial reduction of the amide carbonyl group, the reaction proceeds through the reductive amination of the alcohol with the amine arising from collapse of the intermediate hemiaminal.
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70
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Adam R, Alberico E, Baumann W, Drexler HJ, Jackstell R, Junge H, Beller M. NNP-Type Pincer Imidazolylphosphine Ruthenium Complexes: Efficient Base-Free Hydrogenation of Aromatic and Aliphatic Nitriles under Mild Conditions. Chemistry 2016; 22:4991-5002. [DOI: 10.1002/chem.201504709] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Indexed: 01/05/2023]
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71
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Alsabeh PG, Rosas-Hernández A, Barsch E, Junge H, Ludwig R, Beller M. Iron-catalyzed photoreduction of carbon dioxide to synthesis gas. Catal Sci Technol 2016. [DOI: 10.1039/c5cy01129a] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photocatalytic processes to convert CO2 to useful products including CO and HCOOH are of particular interest as a means to harvest the power of the sun for sustainable energy applications. Herein, we report the photocatalytic reduction of CO2 using iron-based catalysts and visible light generating varying ratios of synthesis gas.
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72
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Mellmann D, Sponholz P, Junge H, Beller M. Formic acid as a hydrogen storage material – development of homogeneous catalysts for selective hydrogen release. Chem Soc Rev 2016; 45:3954-88. [DOI: 10.1039/c5cs00618j] [Citation(s) in RCA: 514] [Impact Index Per Article: 64.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Liquid energy: formic acid is an ideal candidate for catalytic release and storage of hydrogen.
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73
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Lange S, Elangovan S, Cordes C, Spannenberg A, Jiao H, Junge H, Bachmann S, Scalone M, Topf C, Junge K, Beller M. Selective catalytic hydrogenation of nitriles to primary amines using iron pincer complexes. Catal Sci Technol 2016. [DOI: 10.1039/c6cy00834h] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The selective catalytic hydrogenation of nitriles to primary amines with the well-defined Fe(PNPCy) pincer complex 2 is reported.
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74
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Lennox AJJ, Fischer S, Jurrat M, Luo SP, Rockstroh N, Junge H, Ludwig R, Beller M. Copper-Based Photosensitisers in Water Reduction: A More Efficient In Situ Formed System and Improved Mechanistic Understanding. Chemistry 2015; 22:1233-8. [DOI: 10.1002/chem.201503812] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Indexed: 11/05/2022]
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75
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Cabrero-Antonino JR, Alberico E, Drexler HJ, Baumann W, Junge K, Junge H, Beller M. Efficient Base-Free Hydrogenation of Amides to Alcohols and Amines Catalyzed by Well-Defined Pincer Imidazolyl–Ruthenium Complexes. ACS Catal 2015. [DOI: 10.1021/acscatal.5b01955] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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