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Shillito GE, Preston D, Crowley JD, Wagner P, Harris SJ, Gordon KC, Kupfer S. Controlling Excited State Localization in Bichromophoric Photosensitizers via the Bridging Group. Inorg Chem 2024; 63:4947-4956. [PMID: 38437618 PMCID: PMC10951951 DOI: 10.1021/acs.inorgchem.3c04110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 01/18/2024] [Accepted: 01/30/2024] [Indexed: 03/06/2024]
Abstract
A series of photosensitizers comprised of both an inorganic and an organic chromophore are investigated in a joint synthetic, spectroscopic, and theoretical study. This bichromophoric design strategy provides a means by which to significantly increase the excited state lifetime by isolating the excited state away from the metal center following intersystem crossing. A variable bridging group is incorporated between the donor and acceptor units of the organic chromophore, and its influence on the excited state properties is explored. The Franck-Condon (FC) photophysics and subsequent excited state relaxation pathways are investigated with a suite of steady-state and time-resolved spectroscopic techniques in combination with scalar-relativistic quantum chemical calculations. It is demonstrated that the presence of an electronically conducting bridge that facilitates donor-acceptor communication is vital to generate long-lived (32 to 45 μs), charge-separated states with organic character. In contrast, when an insulating 1,2,3-triazole bridge is used, the excited state properties are dominated by the inorganic chromophore, with a notably shorter lifetime of 60 ns. This method of extending the lifetime of a molecular photosensitizer is, therefore, of interest for a range of molecular electronic devices and photophysical applications.
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Affiliation(s)
- Georgina E. Shillito
- Institute
of Physical Chemistry, Friedrich Schiller
University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Dan Preston
- Research
School of Chemistry, Australian National
University, Canberra, ACT 2600, Australia
| | - James D. Crowley
- Department
of Chemistry, University of Otago, 362 Leith Street, Dunedin 9016, New Zealand
- MacDiarmid
Institute for Advanced Materials and Nanotechnology, Wellington, 6012, New Zealand
| | - Pawel Wagner
- University
of Wollongong, Northfields Avenue, Wollongong, NSW 2522, Australia
| | - Samuel J. Harris
- Department
of Chemistry, University of Otago, 362 Leith Street, Dunedin 9016, New Zealand
- MacDiarmid
Institute for Advanced Materials and Nanotechnology, Wellington, 6012, New Zealand
| | - Keith C. Gordon
- Department
of Chemistry, University of Otago, 362 Leith Street, Dunedin 9016, New Zealand
- MacDiarmid
Institute for Advanced Materials and Nanotechnology, Wellington, 6012, New Zealand
| | - Stephan Kupfer
- Institute
of Physical Chemistry, Friedrich Schiller
University Jena, Helmholtzweg 4, 07743 Jena, Germany
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Camara F, Gavaggio T, Dautreppe B, Chauvin J, Pécaut J, Aldakov D, Collomb MN, Fortage J. Electrochemical Properties of a Rhodium(III) Mono-Terpyridyl Complex and Use as a Catalyst for Light-Driven Hydrogen Evolution in Water. Molecules 2022; 27:molecules27196614. [PMID: 36235152 PMCID: PMC9571878 DOI: 10.3390/molecules27196614] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/23/2022] [Accepted: 09/30/2022] [Indexed: 11/16/2022] Open
Abstract
Molecular hydrogen (H2) is considered one of the most promising fuels to decarbonize the industrial and transportation sectors, and its photocatalytic production from molecular catalysts is a research field that is still abounding. The search for new molecular catalysts for H2 production with simple and easily synthesized ligands is still ongoing, and the terpyridine ligand with its particular electronic and coordination properties, is a good candidate to design new catalysts meeting these requirements. Herein, we have isolated the new mono-terpyridyl rhodium complex, [RhIII(tpy)(CH3CN)Cl2](CF3SO3) (Rh-tpy), and shown that it can act as a catalyst for the light-induced proton reduction into H2 in water in the presence of the [Ru(bpy)3]Cl2 (Ru) photosensitizer and ascorbate as sacrificial electron donor. Under photocatalytic conditions, in acetate buffer at pH 4.5 with 0.1 M of ascorbate and 530 μM of Ru, the Rh-tpy catalyst produces H2 with turnover number versus catalyst (TONCat*) of 300 at a Rh concentration of 10 μM, and up to 1000 at a concentration of 1 μM. The photocatalytic performance of Ru/Rh-tpy/HA-/H2A has been also compared with that obtained with the bis-dimethyl-bipyridyl complex [RhIII(dmbpy)2Cl2]+ (Rh2) as a catalyst in the same experimental conditions. The investigation of the electrochemical properties of Rh-tpy in DMF solvent reveals that the two-electrons reduced state of the complex, the square-planar [RhI(tpy)Cl] (RhI-tpy), is quantitatively electrogenerated by bulk electrolysis. This complex is stable for hours under an inert atmosphere owing to the π-acceptor property of the terpyridine ligand that stabilizes the low oxidation states of the rhodium, making this catalyst less prone to degrade during photocatalysis. The π-acceptor property of terpyridine also confers to the Rh-tpy catalyst a moderately negative reduction potential (Epc(RhIII/RhI) = -0.83 V vs. SCE in DMF), making possible its reduction by the reduced state of Ru, [RuII(bpy)(bpy•-)]+ (Ru-) (E1/2(RuII/Ru-) = -1.50 V vs. SCE) generated by a reductive quenching of the Ru excited state (*Ru) by ascorbate during photocatalysis. A Stern-Volmer plot and transient absorption spectroscopy confirmed that the first step of the photocatalytic process is the reductive quenching of *Ru by ascorbate. The resulting reduced Ru species (Ru-) were then able to activate the RhIII-tpy H2-evolving catalyst by reduction generating RhI-tpy, which can react with a proton on a sub-nanosecond time scale to form a RhIII(H)-tpy hydride, the key intermediate for H2 evolution.
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Affiliation(s)
- Fakourou Camara
- DCM, CNRS, Université Grenoble Alpes, 38000 Grenoble, France
- SyMMES, IRIG, CEA, CNRS, Université Grenoble Alpes, 38000 Grenoble, France
| | - Thomas Gavaggio
- DCM, CNRS, Université Grenoble Alpes, 38000 Grenoble, France
| | | | - Jérôme Chauvin
- DCM, CNRS, Université Grenoble Alpes, 38000 Grenoble, France
| | - Jacques Pécaut
- SyMMES, IRIG, CEA, CNRS, Université Grenoble Alpes, 38000 Grenoble, France
| | - Dmitry Aldakov
- SyMMES, IRIG, CEA, CNRS, Université Grenoble Alpes, 38000 Grenoble, France
| | - Marie-Noëlle Collomb
- DCM, CNRS, Université Grenoble Alpes, 38000 Grenoble, France
- Correspondence: (M.-N.C.); (J.F.)
| | - Jérôme Fortage
- DCM, CNRS, Université Grenoble Alpes, 38000 Grenoble, France
- Correspondence: (M.-N.C.); (J.F.)
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Manbeck GF, Fujita E, Brewer KJ. Tetra- and Heptametallic Ru(II),Rh(III) Supramolecular Hydrogen Production Photocatalysts. J Am Chem Soc 2017; 139:7843-7854. [DOI: 10.1021/jacs.7b02142] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Gerald F. Manbeck
- Chemistry
Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Etsuko Fujita
- Chemistry
Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Karen J. Brewer
- Department
of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
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Wang L, Xie Z, Dang S, Sun ZM. Self-Assembly of Tunable Heterometallic Ln-Ru Coordination Polymers with Near-Infrared Luminescence and Magnetocaloric Effect. Chemistry 2017; 23:2852-2857. [DOI: 10.1002/chem.201604869] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Indexed: 01/01/2023]
Affiliation(s)
- Lei Wang
- State Key Laboratory of Polymer Physics and Chemistry; Changchun Institute of Applied Chemistry; Chinese Academy of Sciences; Changchun 130022 P.R. China), Fax: (+86) 431 85262775
| | - Zhigang Xie
- State Key Laboratory of Polymer Physics and Chemistry; Changchun Institute of Applied Chemistry; Chinese Academy of Sciences; Changchun 130022 P.R. China), Fax: (+86) 431 85262775
| | - Song Dang
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry; Chinese Academy of Sciences; Changchun 130022 P.R. China
| | - Zhong-Ming Sun
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry; Chinese Academy of Sciences; Changchun 130022 P.R. China
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