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Shi Y, Li J, Cui C, Wu G, Cheng T. Influence of ligand variation on the deactivation process of metal-to-ligand charge transfer excited states in quadruply bonded dimolybdenum complexes. Phys Chem Chem Phys 2023; 25:32364-32371. [PMID: 37990808 DOI: 10.1039/d3cp03679k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
To explore the dynamics of metal-to-ligand charge transfer (MLCT) excited states involving covalently bonded dimetal units, a series of quadruply bonded dimolybdenum (Mo2) complexes, namely, [Mo2]-ph, [Mo2]-naph, and [Mo2]-anth, were synthesized and characterized. Our investigations reveal a non-radiative process associated with the deactivation of the MLCT state into a low-lying dimetal-centered triplet state (3Mo2-δδ*), resulting in the populated MLCT states in these molecular systems exhibiting either extremely weak emission or being non-emissive. The influence of ligand variation on the dynamics of MLCT states was examined using femtosecond transient absorption spectroscopy, with deactivation time constants determined to be 1.9 ps for [Mo2]-ph, 6.5 ps for [Mo2]-naph, and 49 ps for [Mo2]-anth. This electron transfer behaviour follows an inverse energy-gap law, contrary to the general guideline that applies to the decay of the MLCT state back to the electronic ground state. This result offers valuable insights into understanding the photochemical and photophysical properties of covalently bonded dimetal complexes.
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Affiliation(s)
- Yuqing Shi
- School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, P. R. China.
| | - Juanjuan Li
- School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, P. R. China.
| | - Can Cui
- School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, P. R. China.
| | - Guanzhi Wu
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK
| | - Tao Cheng
- School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, P. R. China.
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Chu C, Yan Y, Ma J, Jin S, Spinney R, Dionysiou DD, Zhang H, Xiao R. Implementation of laser flash photolysis for radical-induced reactions and environmental implications. WATER RESEARCH 2023; 244:120526. [PMID: 37672949 DOI: 10.1016/j.watres.2023.120526] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 08/06/2023] [Accepted: 08/24/2023] [Indexed: 09/08/2023]
Abstract
Confronted with the imperative crisis of water quality deterioration, the pursuit of state-of-the-art decontamination technologies for a sustainable future never stops. Fitting into the framework of suitability, advanced oxidation processes have been demonstrated as powerful technologies to produce highly reactive radicals for the degradation of toxic and refractory contaminants. Therefore, investigations on their radical-induced degradation have been the subject of scientistic and engineering interests for decades. To better understand the transient nature of these radical species and rapid degradation processes, laser flash photolysis (LFP) has been considered as a viable and powerful technique due to its high temporal resolution and rapid response. Although a number of studies exploited LFP for one (or one class of) specific reaction(s), reactions of many possible contaminants with radicals are largely unknown. Therefore, there is a pressing need to critically review its implementation for kinetic quantification and mechanism elucidation. Within this context, we introduce the development process and milestones of LFP with emphasis on compositions and operation principles. We then compare the specificity and suitability of different spectral modes for monitoring radicals and their decay kinetics. Radicals with high environmental relevance, namely hydroxyl radical, sulfate radical, and reactive chlorine species, are selected, and we discuss their generation, detection, and implications within the frame of LFP. Finally, we highlight remaining challenges and future perspectives. This review aims to advance our understandings of the implementation of LFP in radical-induced transient processes, and yield new insights for extrapolating this pump-probe technique to make significant strides in environmental implications.
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Affiliation(s)
- Chu Chu
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Yiqi Yan
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Junye Ma
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Shengye Jin
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Richard Spinney
- Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, Ohio, 45221, USA
| | - Dionysios D Dionysiou
- Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, Ohio, 45221, USA; Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Haijun Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
| | - Ruiyang Xiao
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China.
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Nuin E, Sastre G, Pischel U, Andreu I, Miranda MA. Configuration-Dependent Photoinduced Electron Transfer in Diastereomeric Naphthalene-Amino-Naphthalene Triads. Chemistry 2015. [PMID: 26215923 DOI: 10.1002/chem.201501008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Novel diastereomeric triads containing two naphthalene chromophores have been designed in which an electron-donating amine moiety is covalently integrated into the connecting bridge. Photophysical studies (steady-state and time-resolved fluorescence) in solvents of different polarity have been performed. A remarkable stereodifferentiation in the intramolecular fluorescence quenching was found in acetonitrile. Laser flash photolysis gave rise to naphthalene-derived radical cations, which were also quenched by the amine with an even higher degree of stereodifferentiation. The results are in agreement with thermodynamic estimations and indicate that photoinduced electron transfer (PET) is the main quenching pathway. Furthermore, theoretical calculations have allowed us to explain the experimentally observed stereodifferentiation in PET quenching.
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Affiliation(s)
- Edurne Nuin
- Instituto de Tecnología Química UPV-CSIC, Universitat Politècnica de València, Avenida de los Naranjos s/n, 46022 Valencia (Spain), Fax: (+34) 96-387-9444
| | - German Sastre
- Instituto de Tecnología Química UPV-CSIC, Universitat Politècnica de València, Avenida de los Naranjos s/n, 46022 Valencia (Spain), Fax: (+34) 96-387-9444
| | - Uwe Pischel
- CIQSO-Centro de Investigación en Química Sostenible y Departamento de Ingeniería Química, Química Física y Química Orgánica, Universidad de Huelva, Campus de El Carmen s/n, 21071 Huelva (Spain)
| | - Inmaculada Andreu
- Unidad Mixta de Investigación IIS La Fe-UPV, Hospital Universitari i Politècnic La Fe, Avenida de Fernando Abril Martorell 106, 46026 Valencia (Spain), Fax: (+34) 96-349-4420.
| | - Miguel A Miranda
- Instituto de Tecnología Química UPV-CSIC, Universitat Politècnica de València, Avenida de los Naranjos s/n, 46022 Valencia (Spain), Fax: (+34) 96-387-9444.
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Bonancía P, Vigara L, Galindo F, Luis SV, Jiménez MC, Miranda MA. Triplet excited state behavior of naphthalene-based pseudopeptides in the presence of energy donors. J Phys Chem B 2012; 116:9957-62. [PMID: 22860895 DOI: 10.1021/jp304883u] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In this work, the triplet state behavior of naphthalene-based pseudopeptides with amide-based macrocyclic or lateral chain substructures has been investigated in the presence of benzophenone and/or biphenyl, as suitable energy-donating chromophores. Their behavior has been compared with that of 1,4-dimethylnaphthalene as model compound. In all the cases, the triplet-triplet absorption of naphthalene is detected by transient absorption spectroscopy, upon selective excitation of benzophenone at 355 nm. The kinetics of formation and decay of this species is markedly slower in the pseudopeptides, due to retardation of triplet-triplet energy transfer and exciplex formation. Finally, the delayed fluorescence detected in the model naphthalene is absent in the pseudopeptides. The concept can, in principle, be exploited for the study of excited-state interactions in supramolecular systems.
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Affiliation(s)
- Paula Bonancía
- Departamento de Química/Instituto de Tecnología Química UPV-CSIC, Universitat Politécnica de Valencia, Camino de Vera s/n, 46071 Valencia, Spain
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