1
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Shahid N, Singh AK. Unravelling the kinetics of electro- and photochemical S → O linkage isomerization in Ru(II)-NHC-DMSO complexes utilised for photoinduced substitution reactions. Dalton Trans 2024; 53:12662-12675. [PMID: 39012321 DOI: 10.1039/d4dt01200c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
Our recently reported Ru(III)-NHC complexes 1a and 1b were utilized as suitable precursors to prepare new Ru(II)-NHC-(DMSO)2 complexes 2a and 2b. Complexes 2a and 2b reacted with 2,2'-bipyridine to give complexes 3a and 3b, respectively, with substitution of only one of the DMSO ligands. All new complexes were characterized using various spectroscopic techniques and the molecular structures of 2a and 3a were determined using single-crystal X-ray diffraction technique. Complexes 2a, 2b, 3a, and 3b showed the S → O linkage isomerization of the DMSO ligand upon oxidation of the Ru centre from +II to +III, as confirmed by the thermodynamic and kinetic data obtained from cyclic voltammetry experiments. It was observed that in the bisdimethylsulfoxide complexes 2a and 2b, only one DMSO ligand isomerized, which was further corroborated by the computational studies performed to optimize the geometry of the possible linkage isomers of complexes 2a and 3a in +2 and +3 oxidation states, whereas complexes 3a and 3b showed a high preference for the O-bound isomer in the Ru(III) redox state. The role of NHC in stabilizing the mixed isomer in complexes 2a and 2b and preventing the isomerization of both DMSO ligands coordinated to the Ru centre was studied; moreover, NHC provided good solvent compatibility for photochemical S → O isomerization in all the complexes. Taking advantages of the photoinduced linkage isomerization in 2a and 2b, the synthesis of 3a and 3b was revisited and performed using 2a and 2b, respectively, following a photoinduced substitution reaction in the presence of 2,2'-bipyridine. The kinetics of the reversion from the O-bound to S-bound isomer was found to follow the DMSO-assisted intermolecular S → O isomerization pathway.
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Affiliation(s)
- Nida Shahid
- Department of Chemistry, Indian Institute of Technology-Indore, Simrol, Khandwa Road, 433552, India.
| | - Amrendra K Singh
- Department of Chemistry, Indian Institute of Technology-Indore, Simrol, Khandwa Road, 433552, India.
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2
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Sinha N, Wellauer J, Maisuradze T, Prescimone A, Kupfer S, Wenger OS. Reversible Photoinduced Ligand Substitution in a Luminescent Chromium(0) Complex. J Am Chem Soc 2024; 146:10418-10431. [PMID: 38588581 PMCID: PMC11027151 DOI: 10.1021/jacs.3c13925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 03/13/2024] [Accepted: 03/19/2024] [Indexed: 04/10/2024]
Abstract
Light-triggered dissociation of ligands forms the basis for many compounds of interest for photoactivated chemotherapy (PACT), in which medicinally active substances are released or "uncaged" from metal complexes upon illumination. Photoinduced ligand dissociation is usually irreversible, and many recent studies performed in the context of PACT focused on ruthenium(II) polypyridines and related heavy metal complexes. Herein, we report a first-row transition metal complex, in which photoinduced dissociation and spontaneous recoordination of a ligand unit occurs. Two scorpionate-type tridentate chelates provide an overall six-coordinate arylisocyanide environment for chromium(0). Photoexcitation causes decoordination of one of these six ligating units and coordination of a solvent molecule, at least in tetrahydrofuran and 1,4-dioxane solvents, but far less in toluene, and below detection limit in cyclohexane. Transient UV-vis absorption spectroscopy and quantum chemical simulations point to photoinduced ligand dissociation directly from an excited metal-to-ligand charge-transfer state. Owing to the tridentate chelate design and the substitution lability of the first-row transition metal, recoordination of the photodissociated arylisocyanide ligand unit can occur spontaneously on a millisecond time scale. This work provides insight into possible self-healing mechanisms counteracting unwanted photodegradation processes and seems furthermore relevant in the contexts of photoswitching and (photo)chemical information storage.
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Affiliation(s)
- Narayan Sinha
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
- School
of Chemical Sciences, Indian Institute of
Technology Mandi, Mandi 175075, Himachal Pradesh, India
| | - Joël Wellauer
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Tamar Maisuradze
- Institute
of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Alessandro Prescimone
- Department
of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, 4058 Basel, Switzerland
| | - Stephan Kupfer
- Institute
of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Oliver S. Wenger
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
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3
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Mandal S, Garu P, Chowdhury J, Saha R, Chattopadhyay S. Spectroscopic, structural and computational studies of thiophenolato bridged dirhenium(III,III) complexes. J COORD CHEM 2022. [DOI: 10.1080/00958972.2022.2144266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Suman Mandal
- Department of Chemistry, University of Kalyani, Kalyani, India
| | - Purnananda Garu
- Department of Chemistry, University of Kalyani, Kalyani, India
| | | | - Rajat Saha
- Department of Chemistry, Kazi Nazrul University, Asansol, India
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4
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Vittardi SB, Thapa Magar R, Breen DJ, Rack JJ. A Future Perspective on Phototriggered Isomerizations of Transition Metal Sulfoxides and Related Complexes. J Am Chem Soc 2021; 143:526-537. [PMID: 33400512 DOI: 10.1021/jacs.0c08820] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Photochromic molecules are examples of light-activated bistable molecules. We highlight the design criteria for a class of ruthenium and osmium sulfoxide complexes that undergo phototriggered isomerization of the bound sulfoxide. The mode of action in these complexes is an excited-state isomerization of the sulfoxide from S-bonded to O-bonded. We discuss the basic mechanism for this transformation and highlight specific examples that demonstrate the effectiveness and efficiency of the isomerization. We subsequently discuss future research directions within the field of phototriggered sulfoxide isomerizations on transition metal polypyridine complexes. These efforts involve new synthetic directions, including the choice of metal as well as new ambidentate ligands for isomerization.
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Affiliation(s)
- Sebastian B Vittardi
- Department of Chemistry and Chemical Biology, 300 Terrace Street NE, University of New Mexico, Albuquerque, New Mexico 87131-001 United States
| | - Rajani Thapa Magar
- Department of Chemistry and Chemical Biology, 300 Terrace Street NE, University of New Mexico, Albuquerque, New Mexico 87131-001 United States
| | - Douglas J Breen
- Department of Chemistry and Chemical Biology, 300 Terrace Street NE, University of New Mexico, Albuquerque, New Mexico 87131-001 United States
| | - Jeffrey J Rack
- Department of Chemistry and Chemical Biology, 300 Terrace Street NE, University of New Mexico, Albuquerque, New Mexico 87131-001 United States
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5
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Livshits MY, Wang L, Vittardi SB, Ruetzel S, King A, Brixner T, Rack JJ. An excited state dynamics driven reaction: wavelength-dependent photoisomerization quantum yields in [Ru(bpy) 2(dmso) 2] 2. Chem Sci 2020; 11:5797-5807. [PMID: 34094082 PMCID: PMC8159332 DOI: 10.1039/d0sc00551g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 05/17/2020] [Indexed: 12/21/2022] Open
Abstract
We report the excited-state behavior of a structurally simple bis-sulfoxide complex, cis-S,S-[Ru(bpy)2(dmso)2]2+, as investigated by femtosecond pump-probe spectroscopy. The results reveal that a single photon prompts phototriggered isomerization of one or both dmso ligands to yield a mixture of cis-S,O-[Ru(bpy)2(dmso)2]2+ and cis-O,O-[Ru(bpy)2(dmso)2]2+. The quantum yields of isomerization of each product and relative product distribution are dependent upon the excitation wavelength, with longer wavelengths favoring the double isomerization product, cis-O,O-[Ru(bpy)2(dmso)2]2+. Transient absorption measurements on cis-O,O-[Ru(bpy)2(dmso)2]2+ do not reveal an excited-state isomerization pathway to produce either the S,O or S,S isomers. Femtosecond pulse shaping experiments reveal no change in the product distribution. Pump-repump-probe transient absorption spectroscopy of cis-S,S-[Ru(bpy)2(dmso)2]2+ shows that a pump-repump time delay of 3 ps dramatically alters the S,O : O,O product ratio; pump-repump-probe transient absorption spectroscopy of cis-O,O-[Ru(bpy)2(dmso)2]2+ with a time delay of 3 ps uncovers an excited-state isomerization pathway to produce the S,O isomer. In conjunction with low-temperature steady-state emission spectroscopy, these results are interpreted in the context of an excited-state bifurcating pathway, in which the isomerization product distribution is determined not by thermodynamics, but rather as a dynamics driven reaction.
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Affiliation(s)
- Maksim Y Livshits
- Department of Chemistry and Chemical Biology, University of New Mexico Albuquerque NM 87131 USA
- Department of Chemistry and Biochemistry, Ohio University Athens OH 45701 USA
| | - Lei Wang
- Department of Chemistry and Biochemistry, Ohio University Athens OH 45701 USA
| | - Sebastian B Vittardi
- Department of Chemistry and Chemical Biology, University of New Mexico Albuquerque NM 87131 USA
| | - Stefan Ruetzel
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Albert King
- Department of Chemistry and Chemical Biology, University of New Mexico Albuquerque NM 87131 USA
| | - Tobias Brixner
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Jeffrey J Rack
- Department of Chemistry and Chemical Biology, University of New Mexico Albuquerque NM 87131 USA
- Department of Chemistry and Biochemistry, Ohio University Athens OH 45701 USA
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6
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Li LP, Peng HL, Ye BH. Thermodynamic Resolution and Enantioselective Synthesis of C2-Symmetric Bis-sulfoxides Based on Chiral Iridium(III) Complexes. Inorg Chem 2019; 58:12245-12253. [PMID: 31483628 DOI: 10.1021/acs.inorgchem.9b01682] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Enantiopure Λ-[Ir(dfppy)2(MeCN)2](PF6) and Δ-[Ir(dfppy)2(MeCN)2](PF6) (where dfppy is (4,6-difluoropheny)pyridine) were demonstrated to preferentially react with (S,S)-1,2-bis(arylsulfinyl)ethane and (R,R)-1,2-bis(arylsulfinyl)ethane, respectively, under thermodynamic equilibrium. Sequential treatment of Λ-[Ir(dfppy)2(MeCN)2](PF6) and Δ-[Ir(dfppy)2(MeCN)2](PF6) with C2-symmetric bis-sulfoxides led to diastereoselective formation of the corresponding diastereomers Λ-[Ir(dfppy)2(R,R)-bis-sulfoxide)](PF6) in 90-92% and Δ-[Ir(dfppy)2(S,S)-bis-sulfoxide)](PF6) in 88-90%, respectively. The uncoordinated (R,S)-bis-sulfoxides were afforded in 45% with >97% de values. Enantiopure (S,S)-bis-sulfoxides and (R,R)-bis-sulfoxides were respectively obtained by the release of sulfoxide ligands from the corresponding complexes in the presence of glycine in yields of 20-21% with 97-99% ee values. The enantioreceptors Λ-[Ir(dfppy)2(MeCN)2](PF6) and Δ-[Ir(dfppy)2(MeCN)2](PF6) can be recycled and reused in the next reaction cycle. Moreover, a protocol for asymmetric oxidation of prochiral bis-sulfide into enantiopure C2 symmetric bis-sulfoxide was also developed in a high enantioselectivity. The absolute configurations at the metal centers and sulfur atoms were determined by X-ray crystallography.
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Affiliation(s)
- Li-Ping Li
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry , Sun Yat-sen University , Guangzhou 510275 , China
| | - He-Long Peng
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry , Sun Yat-sen University , Guangzhou 510275 , China
| | - Bao-Hui Ye
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry , Sun Yat-sen University , Guangzhou 510275 , China
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7
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Choi CM, MacAleese L, Dugourd P, Choi MC, Chirot F. Photo-induced linkage isomerization in the gas phase probed by tandem ion mobility and laser spectroscopy. Phys Chem Chem Phys 2018; 20:12223-12228. [PMID: 29687123 DOI: 10.1039/c8cp01833b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Ruthenium complexes involving sulfoxide ligands can undergo linkage isomerization upon light absorption, accompanied by dramatic changes in their optical properties. These remarkable photochromic properties are sensitive to the nature of the ligand as well as to that of the solvent. We used tandem ion mobility spectrometry coupled to mass spectrometry to gain direct experimental insight into the isomerization pathways connecting the different linkage isomers of an isolated ruthenium complex with two dimethyl-sulfoxide ligands. We find that the isomerization behavior of the solvent-free complex differs from that previously reported in the solution-phase, which is in line with recent theoretical predictions.
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Affiliation(s)
- Chang Min Choi
- Mass Spectrometry and Advanced Instrumentation Research Group, Div. of Scientific Instrumentation, Korea Basic Science Institute, Cheongju, Republic of Korea
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8
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Scholz MS, Bull JN, Carrascosa E, Adamson BD, Kosgei GK, Rack JJ, Bieske EJ. Linkage Photoisomerization of an Isolated Ruthenium Sulfoxide Complex: Sequential versus Concerted Rearrangement. Inorg Chem 2018; 57:5701-5706. [PMID: 29663799 DOI: 10.1021/acs.inorgchem.8b00871] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ruthenium sulfoxide complexes undergo thermally reversible linkage isomerization of sulfoxide ligands from S- to O-bound in response to light. Here, we report photoisomerization action spectra for a ruthenium bis-sulfoxide molecular photoswitch, [Ru(bpy)2(bpSO)]2+, providing the first direct evidence for photoisomerization of a transition metal complex in the gas phase. The linkage isomers are separated and isolated in a tandem drift tube ion mobility spectrometer and exposed to tunable laser radiation provoking photoisomerization. Direct switching of the S,S-isomer to the O,O-isomer following absorption of a single photon is the predominant isomerization pathway in the gas phase, unlike in solution, where stepwise isomerization is observed with each sulfoxide ligand switching in turn. The change in isomerization dynamics is attributed to rapid vibrational quenching that suppresses isomerization in solution. Supporting electronic structure calculations predict the wavelengths and intensities of the peaks in the photoisomerization action spectra of the S,S- and S,O-isomers, indicating that they correspond to metal-to-ligand charge transfer (MLCT) and ligand-centered ππ* transitions.
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Affiliation(s)
- Michael S Scholz
- School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
| | - James N Bull
- School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Eduardo Carrascosa
- School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Brian D Adamson
- School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia.,Sandia National Laboratories, Livermore , California 94550 , United States
| | - Gilbert K Kosgei
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Jeffrey J Rack
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Evan J Bieske
- School of Chemistry , University of Melbourne , Parkville , Victoria 3010 , Australia
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9
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Ghosh MK, Mandal S, Islam A, Mohapatra S, Chattopadhyay S. Ruthenium-Carbon(Aryl) Bond Cleavage and Change in the Ligand Coordination Mode in a Four-Membered Ortho-Metalated Ruthenium(II) Organometallics Promoted by Thiolato Ligands. ChemistrySelect 2017. [DOI: 10.1002/slct.201701046] [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]
Affiliation(s)
- Mrinal K. Ghosh
- Department of Chemistry; University of Kalyani; Kalyani, Nadia 741235, WB India
| | - Suman Mandal
- Department of Chemistry; University of Kalyani; Kalyani, Nadia 741235, WB India
| | - Anikul Islam
- Department of Chemistry; University of Kalyani; Kalyani, Nadia 741235, WB India
| | - Sudip Mohapatra
- Department of Chemistry; Missouri University of S & T; Rolla, MO 65409 USA
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10
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Romero MJ, Suárez V, Fernández-Fariña S, Maneiro M, Martínez-Núñez E, Zaragoza G, González-Noya AM, Pedrido R. Effect of the Metal Ion on the Enantioselectivity and Linkage Isomerization of Thiosemicarbazone Helicates. Chemistry 2017; 23:4884-4892. [PMID: 28207181 DOI: 10.1002/chem.201700195] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Indexed: 11/11/2022]
Abstract
The effect of the metal ion and ligand design on the enantioselectivity and linkage isomerization of neutral cobalt and zinc bisthiosemicarbazone metallohelicates has been investigated in this work. The electrochemical synthesis has afforded the enantioselective formation of chirally pure cobalt helicates, and the ΛΛ isomer of a single enantiomer has been crystallized as only product for the cobalt methyl-substituted thiosemicarbazone helicate. Interestingly linkage isomers have been formed from zinc ethyl-substituted thiosemicarbazone helicate enantiomers for the first time. The co-existence of these isomers has been evaluated from the point of view of both experimental results and computational calculations.
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Affiliation(s)
- María J Romero
- Departamento de Química Inorgánica, Facultade de Química, Campus Vida, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, 15782, Spain
| | - Vanesa Suárez
- Departamento de Química Inorgánica, Facultade de Química, Campus Vida, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, 15782, Spain
| | - Sandra Fernández-Fariña
- Departamento de Química Inorgánica, Facultade de Química, Campus Vida, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, 15782, Spain
| | - Marcelino Maneiro
- Departamento de Química Inorgánica, Facultade de Ciencias, Universidade de Santiago de Compostela, 27002, Lugo, Spain
| | - Emilio Martínez-Núñez
- Departamento de Química Física, Facultade de Química, Campus Vida, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, 15782, Spain
| | - Guillermo Zaragoza
- Unidade de Difracción de Raios X, Edificio CACTUS, Universidade de Santiago de Compostela, Campus Sur, Santiago de Compostela, Galicia, 15782, Spain
| | - Ana M González-Noya
- Departamento de Química Inorgánica, Facultade de Química, Campus Vida, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, 15782, Spain
| | - Rosa Pedrido
- Departamento de Química Inorgánica, Facultade de Química, Campus Vida, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, 15782, Spain
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11
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Li H, Zhang L, Zheng L, Li X, Fan X, Zhao Y. Photoisomerization Mechanism of Ruthenium Sulfoxide Complexes: Role of the Metal-Centered Excited State in the Bond Rupture and Bond Construction Processes. Chemistry 2016; 22:14285-92. [DOI: 10.1002/chem.201602441] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Huifang Li
- Key Laboratory of Organo-Pharmaceutical Chemistry; Gannan Normal University; Ganzhou 341000 P. R. China
| | - Lisheng Zhang
- Key Laboratory of Organo-Pharmaceutical Chemistry; Gannan Normal University; Ganzhou 341000 P. R. China
| | - lvyin Zheng
- Key Laboratory of Organo-Pharmaceutical Chemistry; Gannan Normal University; Ganzhou 341000 P. R. China
| | - Xun Li
- Key Laboratory of Organo-Pharmaceutical Chemistry; Gannan Normal University; Ganzhou 341000 P. R. China
| | - Xiaolin Fan
- Key Laboratory of Organo-Pharmaceutical Chemistry; Gannan Normal University; Ganzhou 341000 P. R. China
| | - Yi Zhao
- State Key Laboratory of Physical Chemistry of Solid Surfaces; Xiamen University; Xiamen 361005 P. R. China
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12
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Ligand modification effects on the electrochromic character of ruthenium sulfoxide complexes: a theoretical perspective. Theor Chem Acc 2016. [DOI: 10.1007/s00214-016-1947-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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13
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Swaminathan S, Garcia-Amorós J, Thapaliya ER, Nonell S, Captain B, Raymo FM. Tuning the Activation Wavelength of Photochromic Oxazines. Chemphyschem 2016; 17:1852-9. [DOI: 10.1002/cphc.201600141] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Subramani Swaminathan
- Laboratory for Molecular Photonics, Department of Chemistry; University of Miami; 1301 Memorial Drive Florida 33146-0431 USA
| | - Jaume Garcia-Amorós
- Laboratory for Molecular Photonics, Department of Chemistry; University of Miami; 1301 Memorial Drive Florida 33146-0431 USA
- Grup de Materials Orgànics; Institut de Nanociència i Nanotecnologia (IN2UB); Departament de Química Orgànica; Universitat de Barcelona; Martí i Franqués 1 E-08028 Barcelona Spain
| | - Ek Raj Thapaliya
- Laboratory for Molecular Photonics, Department of Chemistry; University of Miami; 1301 Memorial Drive Florida 33146-0431 USA
| | - Santi Nonell
- Grup O'Enginyeria Molecular; Institut Químic de Sarrià; Universitat Ramón Llull; Via Augusta 390 E-08017 Barcelona Spain
| | - Burjor Captain
- Laboratory for Molecular Photonics, Department of Chemistry; University of Miami; 1301 Memorial Drive Florida 33146-0431 USA
| | - Françisco M. Raymo
- Laboratory for Molecular Photonics, Department of Chemistry; University of Miami; 1301 Memorial Drive Florida 33146-0431 USA
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14
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Li H, Zhang L, Ye M, Fan X. A Comparative Study of the Redox‐Induced Linkage Isomerization of Ruthenium and Osmium Complexes. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201500666] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Huifang Li
- Key Laboratory of Organo‐Pharmaceutical Chemistry, Gannan Normal University, Ganzhou 341000, P. R. China, http://www.gnnu.cn/
| | - Lisheng Zhang
- Key Laboratory of Organo‐Pharmaceutical Chemistry, Gannan Normal University, Ganzhou 341000, P. R. China, http://www.gnnu.cn/
| | - Min Ye
- Key Laboratory of Organo‐Pharmaceutical Chemistry, Gannan Normal University, Ganzhou 341000, P. R. China, http://www.gnnu.cn/
| | - Xiaolin Fan
- Key Laboratory of Organo‐Pharmaceutical Chemistry, Gannan Normal University, Ganzhou 341000, P. R. China, http://www.gnnu.cn/
- Material and Chemical Engineering Department, Pingxiang University, Pingxiang 337055, P. R. China
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15
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Sanz García J, Alary F, Boggio-Pasqua M, Dixon IM, Malfant I, Heully JL. Establishing the Two-Photon Linkage Isomerization Mechanism in the Nitrosyl Complex trans-[RuCl(NO)(py)4]2+ by DFT and TDDFT. Inorg Chem 2015; 54:8310-8. [DOI: 10.1021/acs.inorgchem.5b00998] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Juan Sanz García
- Laboratoire
de Chimie et Physique Quantiques, UMR 5626, IRSAMC, CNRS et Université de Toulouse, 118 route de Narbonne, 31062 Toulouse, France
| | - Fabienne Alary
- Laboratoire
de Chimie et Physique Quantiques, UMR 5626, IRSAMC, CNRS et Université de Toulouse, 118 route de Narbonne, 31062 Toulouse, France
| | - Martial Boggio-Pasqua
- Laboratoire
de Chimie et Physique Quantiques, UMR 5626, IRSAMC, CNRS et Université de Toulouse, 118 route de Narbonne, 31062 Toulouse, France
| | - Isabelle M. Dixon
- Laboratoire
de Chimie et Physique Quantiques, UMR 5626, IRSAMC, CNRS et Université de Toulouse, 118 route de Narbonne, 31062 Toulouse, France
| | - Isabelle Malfant
- Laboratoire
de Chimie de Coordination, CNRS UPR 8241, 205 route de Narbonne, 31077 Toulouse, France
| | - Jean-Louis Heully
- Laboratoire
de Chimie et Physique Quantiques, UMR 5626, IRSAMC, CNRS et Université de Toulouse, 118 route de Narbonne, 31062 Toulouse, France
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16
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King AW, Malizia JP, Engle JT, Ziegler CJ, Rack JJ. Ultrafast spectroscopy and structural characterization of a photochromic isomerizing ruthenium bis-sulfoxide complex. Dalton Trans 2015; 43:17847-55. [PMID: 25273577 DOI: 10.1039/c4dt01402b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Irradiation of [Ru(bpy)2(bpSOp)](PF6)2 (where bpy is 2,2'-bipyridine and bpSOp is 1,3-bis(phenylsulfinyl)propane) results in the formation of two new isomers, namely the S,O- and O,O-bonded species. The crystal structure of the bis-thioether and bis-sulfoxide complexes are reported. NMR spectroscopy of the bis-thioether complex in solution is consistent with the molecular structure determined by diffraction methods. Further, NMR spectroscopy of the bis-sulfoxide complex reveals two conformers in solution, one that is consistent with the solid state structure and a second conformer showing distortion in the aliphatic portion of the chelate ring. Time-resolved visible absorption spectroscopy reveals isomerization time constants of 91 ps in dichloroethane (DCE) and 229 ps in propylene carbonate (PC). Aggregate isomerization quantum yields of 0.57 and 0.42 have been determined in DCE and in PC, respectively. The kinetics of the thermal reversion from the O,O- to S,O-bonded isomer are strongly solvent dependent, occurring with rates of 2.41 × 10(-3) and 4.39 × 10(-5) s(-1) in DCE, and 4.68 × 10(-4) and 9.79 × 10(-6) s(-1) in PC. The two kinetic components are assigned to the two isomers identified in solution.
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Affiliation(s)
- Albert W King
- Department of Chemistry and Biochemistry, Nanoscale and Quantum Phenomena Institute, Ohio University, Clippinger Laboratories, Athens, OH 45701, USA.
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Li H, Zhang L, Fan X, Zhao Y. Theoretical studies on the redox-stimulated isomerization in electrochromic osmium sulfoxide complexes. J Phys Chem A 2015; 119:4244-51. [PMID: 25856566 DOI: 10.1021/acs.jpca.5b02134] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Redox-stimulated intramolecular isomerization of the DMSO ligand in [Os(bpy)2(DMSO)2](2+) (bpy = 2,2'-bipyridine; DMSO = dimethyl sulfoxide) was explored theoretically for better understanding the electrochromic properties of osmium sulfoxide complexes. It is found that the HOMO-LUMO gap is decreased because the electron transfer amount from DMSO1 ligand to Os center using Os-S1 linkage is larger than that using Os-O1 linkage, which makes the absorption of such electrochromic Os(II) sulfoxide complexes red-shifted. Moreover, it is observed that Os-O linkage is preferred by the "hard" Os(III) metal and the "soft" Os(I) metal prefers Os-S linkage, compared with Os(II). Intrinsic reaction pathway calculation results demonstrate that Os-S1 → Os-O1 isomerization is favored by Os(II) oxidation, while Os-O1 → Os-S1 isomerization is much easier to be triggered by reduction of Os(III) or Os(II). In addition, DMSO2 linkage isomerization becomes much harder to proceed attributed to the increased bond-strength between DMSO2 and Os center upon Os(II)-O1 → Os(II)-S1 rearrangement, which makes only one DMSO ligand isomerized observed experimentally.
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Affiliation(s)
- Huifang Li
- †Key Laboratory of Organo-Pharmaceutical Chemistry, Gannan Normal University, Ganzhou 341000, R. R. China
| | - Lisheng Zhang
- †Key Laboratory of Organo-Pharmaceutical Chemistry, Gannan Normal University, Ganzhou 341000, R. R. China
| | - Xiaolin Fan
- †Key Laboratory of Organo-Pharmaceutical Chemistry, Gannan Normal University, Ganzhou 341000, R. R. China
| | - Yi Zhao
- ‡State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, P.R. China
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DeWitt KM, To TT, Heilweil EJ, Burkey TJ. Linkage Isomerization via Geminate Cage or Bimolecular Mechanisms: Time-Resolved Investigations of an Organometallic Photochrome. J Phys Chem B 2015; 119:5531-6. [PMID: 25806597 DOI: 10.1021/jp513033j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The extent of the photoinitiated linkage isomerization of dicarbonyl(3-cyanomethylpyridine-κN)(η(5)-methylcyclopentadienyl)manganese (4) to dicarbonyl(3-cyano-κN-methylpyridine)(η(5)-methylcyclopentadienyl)manganese (5) was examined by time-resolved infrared spectroscopy on picosecond to microsecond time scales in room temperature isooctane to determine the extent the isomerization occurs as a geminate cage rearrangement. We previously reported that a substantial part of the conversion between 4 and 5 must be a bimolecular reaction between a solvent coordinated dicarbonyl(η(5)-methylcyclopentadienyl)manganese (3) and uncoordinated 3-cyanomethylpyridine. For the purpose of designing a molecular device, it would be desirable for the photoisomerization to occur in a geminate cage reaction, because the faster the isomerization, the less opportunity for side reactions to occur. In this study, assignments of transients are identified by comparison with transients observed for model reactions. Within 100 μs after photolysis of 4 in isooctane, no 5 is observed. Instead, the solvent coordinated 3 is observed within 25 ps after irradiation. The formation of 5 is observed only in the presence of 9 mM 3-cyanomethylpyridine but not until 10-50 μs after irradiation of 4. Within the limits of detection, these results indicate the conversion of 4 to 5 occurs exclusively via a bimolecular reaction of 3-cyanomethylpyridine with solvent coordinated 3 and not a geminate cage reaction between 3-cyanomethylpyridine and the dicarbonyl(η(5)-methylcyclopentadienyl)manganese fragment.
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Affiliation(s)
- Kristy M DeWitt
- †Radiation Physics Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8443, United States
| | - Tung T To
- †Radiation Physics Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8443, United States
| | - Edwin J Heilweil
- †Radiation Physics Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8443, United States
| | - Theodore J Burkey
- ‡Department of Chemistry, The University of Memphis, Memphis, Tennessee 38152-3550, United States
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King AW, Wang L, Rack JJ. Excited state dynamics and isomerization in ruthenium sulfoxide complexes. Acc Chem Res 2015; 48:1115-22. [PMID: 25761274 DOI: 10.1021/ar500396a] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Molecular photochromic compounds are those that interconvert between two isomeric forms with light. The two isomeric forms display distinct electronic and molecular structures and must not be in equilibrium with one another. These light-activated molecular switch compounds have found wide application in areas of study ranging from chemical biology to materials science, where conversion from one isomeric form to another by light prompts a response in the environment (e.g., protein or polymeric material). Certain ruthenium and osmium polypyridine sulfoxide complexes are photochromic. The mode of action is a phototriggered isomerization of the sulfoxide from S- to O-bonded. The change in ligation drastically alters both the spectroscopic and electrochemical properties of the metal complex. Our laboratory has pioneered the preparation and study of these complexes. In particular, we have applied femtosecond pump-probe spectroscopy to reveal excited state details of the isomerization mechanism. The data from numerous complexes allowed us to predict that the isomerization was nonadiabatic in nature, defined as occurring from a S-bonded triplet excited state (primarily metal-to-ligand charge transfer in character) to an O-bonded singlet ground state potential energy surface. This prediction was corroborated by high-level density functional theory calculations. An intriguing aspect of this reactivity is the coupling of nuclear motion to the electronic wave function and how this coupling affects motions productive for isomerization. In an effort to learn more about this coupling, we designed a project to examine phototriggered isomerization in bis-sulfoxide complexes. The goal of these studies was to determine whether certain complexes could be designed in which a single photon excitation event would prompt two sulfoxide isomerizations. We employed chelating sulfoxides in this study and found that both the nature of the chelate ring and the R group on the sulfoxide affect the photochemical reactivity. For example, this reactivity may be tuned such that two sulfoxide ligands isomerize sequentially following two successive excitations or that two sulfoxide ligands isomerize following a single excitation. This Account explains our understanding to date of this photochemistry.
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Affiliation(s)
- Albert W. King
- Nanoscale and Quantum Phenomena
Institute, Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, United States
| | - Lei Wang
- Nanoscale and Quantum Phenomena
Institute, Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, United States
| | - Jeffrey J. Rack
- Nanoscale and Quantum Phenomena
Institute, Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, United States
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Li H, Zhang L, Wang Y, Fan X. Theoretical studies on the photoisomerization mechanism of osmium(ii) sulfoxide complexes. RSC Adv 2015. [DOI: 10.1039/c5ra06723e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Role of 3LF state in the photoisomerization mechanism of photochromic osmium sulfoxide complex, [Os(bpy)2(DMSO)2]2+, is examined theoretically.
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Affiliation(s)
- Huifang Li
- Key Laboratory of Organo-Pharmaceutical Chemistry
- Gannan Normal University
- Ganzhou 341000
- P. R. China
| | - Lisheng Zhang
- Key Laboratory of Organo-Pharmaceutical Chemistry
- Gannan Normal University
- Ganzhou 341000
- P. R. China
| | - Yanfei Wang
- Key Laboratory of Organo-Pharmaceutical Chemistry
- Gannan Normal University
- Ganzhou 341000
- P. R. China
| | - Xiaolin Fan
- Key Laboratory of Organo-Pharmaceutical Chemistry
- Gannan Normal University
- Ganzhou 341000
- P. R. China
- Material and Chemical Engineering Department
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Li H, Zhang L, Lin H, Fan X. A DFT-D study on the electrochromic mechanism of ruthenium sulfoxide complexes. RSC Adv 2014. [DOI: 10.1039/c4ra06047d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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King AW, McClure BA, Jin Y, Rack JJ. Investigating the effects of solvent on the ultrafast dynamics of a photoreversible ruthenium sulfoxide complex. J Phys Chem A 2014; 118:10425-32. [PMID: 25137451 DOI: 10.1021/jp504078g] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The photochromic complex [Ru(bpy)2(pySO)](2+) [pySO is 2-(isopropylsulfinylmethyl)pyridine] undergoes wavelength specific, photoreversible S → O and O → S linkage isomerizations. Irradiation of the ground state S-bonded complex with blue light produces the O-bonded isomer, while irradiation of the O-bonded isomer with green light produces the S-bonded isomer. Furthermore, isomerization time constants are solvent-dependent. Ultrafast transient absorption spectroscopy has been employed to investigate the relaxation processes that lead to S → O isomerization in 1,2-dichloroethane, propylene carbonate, and ethylene glycol. The isomerization is most rapid in 1,2-dichloroethane and slowest in ethylene glycol. Photochemical reversion of the O-bonded isomer in propylene carbonate has further been investigated and indicates similar relaxation or isomerization kinetics, though the excited states that lead to isomerization are distinct between the S- and O-bonded isomers.
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Affiliation(s)
- Albert W King
- Nanoscale and Quantum Phenomena Institute, Department of Chemistry and Biochemistry, Ohio University , Athens, Ohio 45701, United States
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Göttle AJ, Alary F, Dixon IM, Heully JL, Boggio-Pasqua M. Unravelling the S → O linkage photoisomerization mechanisms in cis- and trans-[Ru(bpy)2(DMSO)2](2+) using density functional theory. Inorg Chem 2014; 53:6752-60. [PMID: 24932513 DOI: 10.1021/ic500546q] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A mechanistic study of the intramolecular S → O linkage photoisomerization in the cis and trans isomers of [Ru(bpy)2(DMSO)2](2+) was performed using density functional theory. This study reveals that for the cis isomer the linkage photoisomerization of the two DMSO ligands occurs sequentially in the lowest triplet excited state and can either be achieved by a one-photon or by a two-photon mechanism. A mechanistic picture of the S → O photoisomerization of the trans isomer is also proposed. This work especially highlights that both adiabatic and nonadiabatic processes are involved in these mechanisms and that their coexistence is responsible for the rich photophysics and photochemical properties observed experimentally for the studied complexes. The different luminescent behavior experimentally observed at low temperature between the cis and trans isomers is rationalized based on the peculiarity of the topology of the triplet excited-state potential energy surfaces.
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Affiliation(s)
- Adrien J Göttle
- Laboratoire de Chimie et Physique Quantiques, UMR 5626 CNRS/Université Paul Sabatier-Toulouse III , 118 route de Narbonne, 31062 Toulouse, France
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Li H, Zhang L, Lin H, Fan X. A DFT-D study on the electronic and photophysical properties of ruthenium (II) complex with a chelating sulfoxide group. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.04.048] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Garg K, King AW, Rack JJ. One photon yields two isomerizations: large atomic displacements during electronic excited-state dynamics in ruthenium sulfoxide complexes. J Am Chem Soc 2014; 136:1856-63. [PMID: 24438000 DOI: 10.1021/ja409262r] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Photochromic compounds efficiently transduce photonic energy to potential energy for excited-state bond-breaking and bond-forming reactions. A critical feature of this reaction is the nature of the electronic excited-state potential energy surface and how this surface facilitates large nuclear displacements and rearrangements. We have prepared two photochromic ruthenium sulfoxide complexes that feature two isomerization reactions following absorption of a single photon. We show by femtosecond transient absorption spectroscopy that this reaction is complete within a few hundred picoseconds and suggest that isomerization occurs along a conical intersection seam formed by the ground-state and excited-state potential energy surfaces.
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Affiliation(s)
- Komal Garg
- Nanoscale and Quantum Phenomena Institute, Department of Chemistry and Biochemistry, Ohio University , Athens, Ohio 45701, United States
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Li Z, Leed NA, Dickson-Karn NM, Dunbar KR, Turro C. Directional charge transfer and highly reducing and oxidizing excited states of new dirhodium(ii,ii) complexes: potential applications in solar energy conversion. Chem Sci 2014. [DOI: 10.1039/c3sc52366g] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Kato M, Unoura K, Takayanagi T, Ikeda Y, Fujihara T, Nagasawa A. Preferential behavior on donating atoms of an ambidentate ligand 2-methylisothiazol-3(2H)-one in its metal complexes. Inorg Chem 2013; 52:13375-83. [PMID: 24205862 DOI: 10.1021/ic401673z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Five metal complexes of 2-methylisothiazol-3(2H)-one (MIO), [Co(III)(NH3)5(MIO)](3+), [Ru(II)(NH3)5(MIO)](2+), [Ru(III)(NH3)5(MIO)](3+), [Pt(II)Cl3(MIO)](-), and trans-[U(VI)O2(NO3)2(MIO)2], were synthesized, and their structures were determined by single-crystal X-ray crystallography. MIO is an ambidentate ligand and coordinates to metal centers through its oxygen atom in the cobalt(III), ruthenium(III), and uranium(VI) complexes and through its sulfur atom in the ruthenium(II) and platinum(III) complexes. This result suggests that MIO shows preferential behavior on its donating atoms. We also studied the electron-donor abilities of the oxygen and sulfur atoms of MIO. Various physical measurements on the conjugate acid of MIO and the MIO complexes allowed us to determine an acid dissociation constant (pKa) and donor number (DN) for the oxygen atom of MIO and Lever's electrochemical parameter (EL) and a relative covalency parameter (kL) for the sulfur atom.
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Affiliation(s)
- Masaru Kato
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University , 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570, Japan
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Choudhuri MMR, Crutchley RJ. Phenylcyanamide Ligand Control of Photo-Induced Linkage Isomerism. Inorg Chem 2013; 52:14404-10. [DOI: 10.1021/ic402600h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Garg K, Engle JT, Ziegler CJ, Rack JJ. Tuning excited state isomerization dynamics through ground state structural changes in analogous ruthenium and osmium sulfoxide complexes. Chemistry 2013; 19:11686-95. [PMID: 23861290 DOI: 10.1002/chem.201301553] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Indexed: 11/07/2022]
Abstract
The complexes [Ru(bpy)2(pyESO)](PF6)2 and [Os(bpy)2(pyESO)](PF6)2, in which bpy is 2,2'-bipyridine and pyESO is 2-((isopropylsulfinyl)ethyl)pyridine, were prepared and studied by (1)H NMR, UV-visible and ultrafast transient absorption spectroscopy, as well as by electrochemical methods. Crystals suitable for X-ray structural analysis were grown for [Ru(bpy)2(pyESO)](PF6)2. Cyclic voltammograms of both complexes provide evidence for S→O and O→S isomerization as these voltammograms are described by an ECEC (electrochemical-chemical electrochemical-chemical) mechanism in which isomerization follows Ru(2+) oxidation and Ru(3+) reduction. The S- and O-bonded Ru(3+/2+) couples appear at 1.30 and 0.76 V versus Ag/AgCl in propylene carbonate. For [Os(bpy)2(pyESO)](PF6)2, these couples appear at 0.97 and 0.32 V versus Ag/AgCl in acetonitrile, respectively. Charge-transfer excitation of [Ru(bpy)2(pyESO)](PF6)2 results in a significant change in the absorption spectrum. The S-bonded isomer of [Ru(bpy)2(pyESO)](2+) features a lowest energy absorption maximum at 390 nm and the O-bonded isomer absorbs at 480 nm. The quantum yield of isomerization in [Ru(bpy)2(pyESO)](2+) was found to be 0.58 in propylene carbonate and 0.86 in dichloroethane solution. Femtosecond transient absorption spectroscopic measurements were collected for both complexes, revealing time constants of isomerizations of 81 ps (propylene carbonate) and 47 ps (dichloroethane) in [Ru(bpy)2(pyESO)](2+). These data and a model for the isomerizing complex are presented. A striking conclusion from this analysis is that expansion of the chelate ring by a single methylene leads to an increase in the isomerization time constant by nearly two orders of magnitude.
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Affiliation(s)
- Komal Garg
- Department of Chemistry and Biochemistry, Nanoscale and Quantum Phenomena Institute, Clippinger Laboratories, Ohio University, Athens, OH 45701, USA
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