1
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Towards Optimized Photoluminescent Copper(I) Phenanthroline-Functionalized Complexes: Control of the Photophysics by Symmetry-Breaking and Spin–Orbit Coupling. MATERIALS 2022; 15:ma15155222. [PMID: 35955157 PMCID: PMC9369739 DOI: 10.3390/ma15155222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/19/2022] [Accepted: 07/21/2022] [Indexed: 11/17/2022]
Abstract
The electronic and structural alterations induced by the functionalization of the 1,10-phenanthroline (phen) ligand in [Cu(I) (phen-R2)2]+ complexes (R=H, CH3, tertio-butyl, alkyl-linkers) and their consequences on the luminescence properties and thermally activated delay fluorescence (TADF) activity are investigated using the density functional theory (DFT) and its time-dependent (TD) extension. It is shown that highly symmetric molecules with several potentially emissive nearly-degenerate conformers are not promising because of low S1/S0 oscillator strengths together with limited or no S1/T1 spin–orbit coupling (SOC). Furthermore, steric hindrance, which prevents the flattening of the complex upon irradiation, is a factor of instability. Alternatively, linking the phenanthroline ligands offers the possibility to block the flattening while maintaining remarkable photophysical properties. We propose here two promising complexes, with appropriate symmetry and enough rigidity to warrant stability in standard solvents. This original study paves the way for the supramolecular design of new emissive devices.
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2
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Tran JH, Traber P, Seidler B, Görls H, Gräfe S, Schulz M. Ligand‐Induced Donor State Destabilisation – A New Route to Panchromatically Absorbing Cu(I) Complexes. Chemistry 2022; 28:e202200121. [PMID: 35263478 PMCID: PMC9315043 DOI: 10.1002/chem.202200121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Indexed: 11/16/2022]
Abstract
The intense absorption of light to covering a large part of the visible spectrum is highly desirable for solar energy conversion schemes. To this end, we have developed novel anionic bis(4H‐imidazolato)Cu(I) complexes (cuprates), which feature intense, panchromatic light absorption properties throughout the visible spectrum and into the NIR region with extinction coefficients up to 28,000 M−1 cm−1. Steady‐state absorption, (spectro)electrochemical and theoretical investigations reveal low energy (Vis to NIR) metal‐to‐ligand charge‐transfer absorption bands, which are a consequence of destabilized copper‐based donor states. These high‐lying copper‐based states are induced by the σ‐donation of the chelating anionic ligands, which also feature low energy acceptor states. The optical properties are reflected in very low, copper‐based oxidation potentials and three ligand‐based reduction events. These electronic features reveal a new route to panchromatically absorbing Cu(I) complexes.
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Affiliation(s)
- Jens H. Tran
- Institute of Physical Chemistry Friedrich Schiller University Jena Helmholtzweg 4 07743 Jena Germany
| | - Philipp Traber
- Institute of Physical Chemistry Friedrich Schiller University Jena Helmholtzweg 4 07743 Jena Germany
| | - Bianca Seidler
- Institute of Physical Chemistry Friedrich Schiller University Jena Helmholtzweg 4 07743 Jena Germany
| | - Helmar Görls
- Institute of Inorganic and Analytical Chemistry Friedrich Schiller University Jena Humboldtstr. 8 07743 Jena Germany
| | - Stefanie Gräfe
- Institute of Physical Chemistry Friedrich Schiller University Jena Helmholtzweg 4 07743 Jena Germany
- Fraunhofer Institute for Applied Optics and Precision Engineering (Fraunhofer IOF) Albert-Einstein-Str.7 07745 Jena Germany
| | - Martin Schulz
- Institute of Physical Chemistry Friedrich Schiller University Jena Helmholtzweg 4 07743 Jena Germany
- Department Functional Interfaces Leibniz Institute of Photonic Technology Jena (Leibniz-IPHT) Albert-Einstein-Str. 9 07745 Jena Germany
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3
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Nadurata VL, Hay MA, Janetzki JT, Gransbury GK, Boskovic C. Rich redox-activity and solvatochromism in a family of heteroleptic cobalt complexes. Dalton Trans 2021; 50:16631-16646. [PMID: 34752591 DOI: 10.1039/d1dt03327a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The combination of redox-active metals with redox-active ligands can lead to interesting charge transfer behaviours, including valence tautomerism and solvatochromism. With the aim of investigating a relatively underexplored redox-active metal/redox-active ligand combination, complexes [CoII(acac)2(X-BIAN)] (acac- = acetylacetonate; X-BIAN = bis(4-X-phenyl)iminoacenaphthene; 1: X = -CF3, 2: X = -Cl, 3: X = -H, 4: X = -Me) and [CoIII(acac)2(Me-BIAN)]+ (5+) have been synthesised and characterised. At all temperatures investigated, and in both the solid and solution state, complexes 1-4 exist in a CoII-BIAN0 charge distribution, while 5+ adopts a CoIII-BIAN0 charge distribution. In the case of 1-4, the potential CoIII-BIAN˙- valence tautomer is inaccesible; the energy ordering between the ground CoII-BIAN0 state and the excited CoIII-BIAN˙- state must be reversed in order for an entropically driven interconversion to be possible. The energy gap between the states can be monitored via metal-to-ligand charge transfer bands in the visible region. We demonstrate tuning of this energy gap by varying the electronic properties of the BIAN ligand, as well as by controlling the molecular environment through solvent choice. Solvatochromic analysis, in combination with crystallographic evidence, allows elucidation of the specific solvent-solute interactions that govern the molecular behaviour of 1-4, affording insights that can inform potential future applications in sensing and switching.
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Affiliation(s)
- Vincent L Nadurata
- School of Chemistry, University of Melbourne, Melbourne, 3010 Victoria, Australia.
| | - Moya A Hay
- School of Chemistry, University of Melbourne, Melbourne, 3010 Victoria, Australia.
| | - Jett T Janetzki
- School of Chemistry, University of Melbourne, Melbourne, 3010 Victoria, Australia.
| | - Gemma K Gransbury
- School of Chemistry, University of Melbourne, Melbourne, 3010 Victoria, Australia.
| | - Colette Boskovic
- School of Chemistry, University of Melbourne, Melbourne, 3010 Victoria, Australia.
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4
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Grupe M, Boden P, Di Martino‐Fumo P, Gui X, Bruschi C, Israil R, Schmitt M, Nieger M, Gerhards M, Klopper W, Riehn C, Bizzarri C, Diller R. Time-Resolved Spectroscopy and Electronic Structure of Mono-and Dinuclear Pyridyl-Triazole/DPEPhos-Based Cu(I) Complexes. Chemistry 2021; 27:15251-15270. [PMID: 34550622 PMCID: PMC8597052 DOI: 10.1002/chem.202102760] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Indexed: 12/20/2022]
Abstract
Chemical and spectroscopic characterization of the mononuclear photosensitizers [(DPEPhos)Cu(I)(MPyrT)]0/+ (CuL, CuLH) and their dinuclear analogues (Cu2 L', Cu2 L'H2 ), backed by (TD)DFT and high-level GW-Bethe-Salpeter equation calculations, exemplifies the complex influence of charge, nuclearity and structural flexibility on UV-induced photophysical pathways. Ultrafast transient absorption and step-scan FTIR spectroscopy reveal flattening distortion in the triplet state of CuLH as controlled by charge, which also appears to have a large impact on the symmetry of the long-lived triplet states in Cu2 L' and Cu2 L'H2 . Time-resolved luminescence spectroscopy (solid state), supported by transient photodissociation spectroscopy (gas phase), confirm a lifetime of some tens of μs for the respective triplet states, as well as the energetics of thermally activated delayed luminescence, both being essential parameters for application of these materials based on earth-abundant copper in photocatalysis and luminescent devices.
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Affiliation(s)
- Merten Grupe
- Department of PhysicsTU KaiserslauternErwin-Schrödinger-Straße 4667663KaiserslauternGermany
| | - Pit Boden
- Department of ChemistryTU KaiserslauternErwin-Schrödinger-Straße 5267663KaiserslauternGermany
| | - Patrick Di Martino‐Fumo
- Department of ChemistryTU KaiserslauternErwin-Schrödinger-Straße 5267663KaiserslauternGermany
| | - Xin Gui
- Institute of Physical ChemistryKarlsruhe Institute of Technology (KIT)Fritz-Haber-Weg 276131KarlsruheGermany
| | - Cecilia Bruschi
- Institute of Organic Chemistry (IOC)Karlsruhe Institute of Technology (KIT)Fritz-Haber-Weg 676131KarlsruheGermany
| | - Roumany Israil
- Department of ChemistryTU KaiserslauternErwin-Schrödinger-Straße 5267663KaiserslauternGermany
| | - Marcel Schmitt
- Department of ChemistryTU KaiserslauternErwin-Schrödinger-Straße 5267663KaiserslauternGermany
| | - Martin Nieger
- Department of ChemistryUniversity of HelsinkiA.I. Virtasen aukio 100014HelsinkiFinland
| | - Markus Gerhards
- Department of ChemistryTU KaiserslauternErwin-Schrödinger-Straße 5267663KaiserslauternGermany
- Research Center OPTIMASErwin-Schrödinger-Straße 4667663KaiserslauternGermany
| | - Wim Klopper
- Institute of Physical ChemistryKarlsruhe Institute of Technology (KIT)Fritz-Haber-Weg 276131KarlsruheGermany
| | - Christoph Riehn
- Department of ChemistryTU KaiserslauternErwin-Schrödinger-Straße 5267663KaiserslauternGermany
- Research Center OPTIMASErwin-Schrödinger-Straße 4667663KaiserslauternGermany
| | - Claudia Bizzarri
- Institute of Organic Chemistry (IOC)Karlsruhe Institute of Technology (KIT)Fritz-Haber-Weg 676131KarlsruheGermany
| | - Rolf Diller
- Department of PhysicsTU KaiserslauternErwin-Schrödinger-Straße 4667663KaiserslauternGermany
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5
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Müller C, Schulz M, Obst M, Zedler L, Gräfe S, Kupfer S, Dietzek B. Role of MLCT States in the Franck-Condon Region of Neutral, Heteroleptic Cu(I)-4 H-imidazolate Complexes: A Spectroscopic and Theoretical Study. J Phys Chem A 2020; 124:6607-6616. [PMID: 32701275 DOI: 10.1021/acs.jpca.0c04351] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The impact of the electronic structure of a series of 4H-imidazolate ligands in neutral, heteroleptic Cu(I) complexes is investigated. Remarkable broad and strong ligand-dependent absorption in the visible range of the electromagnetic spectrum renders the studied complexes promising photosensitizers for photocatalytic applications. The electronic structure of the Cu(I) complexes and the localization of photoexcited states in the Franck-Condon region are unraveled by means of UV-vis absorption and resonance Raman (rR) spectroscopy supported by time-dependent density functional theory (TD-DFT) calculations. The visible absorption bands stem from a superposition of bright metal-to-ligand charge-transfer (MLCT) and π-π* as well as weakly absorbing MLCT states. Additionally, the analysis of involved molecular orbitals and rR spectra upon excitation of MLCT and π-π* states highlights the impact of the electronic structure of the 4H-imidazolate ligands on the properties of the corresponding Cu(I) complexes to avail a toolbox for predictive studies and efficient complex design.
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Affiliation(s)
- Carolin Müller
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany.,Leibniz Institute of Photonic Technology, Albert-Einstein-Straße 9, 07745 Jena, Germany
| | - Martin Schulz
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Marc Obst
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Linda Zedler
- Leibniz Institute of Photonic Technology, Albert-Einstein-Straße 9, 07745 Jena, Germany
| | - Stefanie Gräfe
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Stephan Kupfer
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Benjamin Dietzek
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany.,Leibniz Institute of Photonic Technology, Albert-Einstein-Straße 9, 07745 Jena, Germany.,Center for Energy and Environmental Chemistry Jena (CEEC Jena), Friedrich Schiller University Jena, Lessingstraße 8, 07743 Jena, Germany
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6
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Outis M, Rosa V, Laia CAT, Lima JC, Barroso S, Carvalho AL, Calhorda MJ, Avilés T. Synthesis, Crystal Structure, and DFT Study of Two New Dinuclear Copper(I) Complexes Bearing Ar‐BIAN Ligands Functionalized with NO
2
Groups. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Mani Outis
- LAQV REQUIMTE Universidade Nova de Lisboa 2829–516 Caparica Portugal
| | - Vitor Rosa
- LAQV REQUIMTE Universidade Nova de Lisboa 2829–516 Caparica Portugal
| | - César A. T. Laia
- LAQV REQUIMTE Universidade Nova de Lisboa 2829–516 Caparica Portugal
| | - João Carlos Lima
- LAQV REQUIMTE Universidade Nova de Lisboa 2829–516 Caparica Portugal
| | - Sónia Barroso
- UCIBIO REQUIMTE Universidade Nova de Lisboa 2829–516 Caparica Portugal
| | | | - Maria José Calhorda
- BioISI ‐ Biosystems & Integrative Sciences Institute Departamento de Química e Bioquímica Universidade de Lisboa 1749–016 Lisboa Portugal
| | - Teresa Avilés
- LAQV REQUIMTE Universidade Nova de Lisboa 2829–516 Caparica Portugal
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7
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Maier TM, Coburger P, van Leest NP, Hey-Hawkins E, Wolf R. Direct synthesis of an anionic 13-vertex closo-cobaltacarborane cluster. Dalton Trans 2019; 48:15772-15777. [PMID: 31612881 DOI: 10.1039/c9dt03111a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Reaction of 1,2-bis(diphenylphosphino)-ortho-carborane (L) with [K(thf){(MesBIAN)Co(η4-cod)}] (1, MesBIAN = bis(mesityliminoace-naphthene)diimine, cod = 1,5-cyclooctadiene) affords an anionic 13-vertex closo-cobaltacarborane cluster (2) in one step. The mechanism of this transformation has been studied by experimental and quantum chemical techniques, which suggest that a series of outer-sphere electron transfer and isomerisation processes occurs. This work shows that low-valent metalate anions are promising reagents for the synthesis of anionic metallacarborane clusters.
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Affiliation(s)
- Thomas M Maier
- University of Regensburg, Institute of Inorganic Chemistry, 93040 Regensburg, Germany.
| | - Peter Coburger
- University of Regensburg, Institute of Inorganic Chemistry, 93040 Regensburg, Germany. and Leipzig University, Institute of Inorganic Chemistry, Johannisallee 29, 04103 Leipzig, Germany.
| | - Nicolaas P van Leest
- Van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam (UvA) Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Evamarie Hey-Hawkins
- Leipzig University, Institute of Inorganic Chemistry, Johannisallee 29, 04103 Leipzig, Germany.
| | - Robert Wolf
- University of Regensburg, Institute of Inorganic Chemistry, 93040 Regensburg, Germany.
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8
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Ng YY, Tan LJ, Ng SM, Chai YT, Ganguly R, Du Y, Yeow EKL, Soo HS. Spectroscopic Characterization and Mechanistic Studies on Visible Light Photoredox Carbon–Carbon Bond Formation by Bis(arylimino)acenaphthene Copper Photosensitizers. ACS Catal 2018. [DOI: 10.1021/acscatal.8b02502] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yik Yie Ng
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Lisa Jiaying Tan
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Shue Mei Ng
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Yoke Tin Chai
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Rakesh Ganguly
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Yonghua Du
- Institute of Chemical and Engineering Sciences A*STAR, 1 Pesek Road, Singapore 627833
| | - Edwin Kok Lee Yeow
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Han Sen Soo
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
- Solar Fuels Laboratory, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
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9
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Liu B, Monro S, Lystrom L, Cameron CG, Colon K, Yin H, Kilina S, McFarland SA, Sun W. Photophysical and Photobiological Properties of Dinuclear Iridium(III) Bis-tridentate Complexes. Inorg Chem 2018; 57:9859-9872. [PMID: 30091916 PMCID: PMC6337720 DOI: 10.1021/acs.inorgchem.8b00789] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A series of cationic dinuclear iridium(III) complexes (Ir1-Ir5) bearing terpyridine-capped fluorenyl bridging ligands and different polypyridyl or cyclometalating terminal tridentate ligands were synthesized, characterized, and evaluated for their photophysical and photobiological activities. The influence of the bridging and terminal ligands on the photophysical properties of the complexes was investigated by UV-vis absorption, emission, and transient absorption spectroscopy and simulated by TDDFT calculations. All of the complexes displayed strong bridging-ligand localized visible 1π,π* absorption and red- or near-infrared phosphorescence as well as broad triplet excited-state absorption across both visible and NIR wavelengths. These triplet states were assigned as predominantly 3π,π* for Ir1 (τ = 3.1 μs) and Ir4 (τ = 48 μs) and 3CT (charge transfer) for Ir2, Ir3, and Ir5 (τ = 1.7-2.7 μs). Complexes Ir1-Ir5 acted as in vitro photodynamic therapy (PDT) agents toward human SK-MEL-28 melanoma cells when activated with visible light, with submicromolar photocytotoxicity and phototherapeutic indices ranging from 20 to almost 300. The in vitro PDT effects with visible light did not correlate with singlet oxygen (1O2) quantum yields or DNA photocleaving capacity probed under cell-free conditions. All of the Ir(III) complexes phosphoresced brightly when associated with compromised cells (with or without light treatment) and exhibited photoactivated cellular uptake, highlighting the theranostic potential of this new class of Ir(III) complex photosensitizers.
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Affiliation(s)
- Bingqing Liu
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58108-6050, USA
| | - Susan Monro
- Department of Chemistry, Acadia University, 6 University Avenue, Wolfville, NS B4P 2R6, Canada
| | - Levi Lystrom
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58108-6050, USA
| | - Colin G. Cameron
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402-6170, USA
| | - Katsuya Colon
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402-6170, USA
| | - Huimin Yin
- Department of Chemistry, Acadia University, 6 University Avenue, Wolfville, NS B4P 2R6, Canada
| | - Svetlana Kilina
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58108-6050, USA
| | - Sherri A. McFarland
- Department of Chemistry, Acadia University, 6 University Avenue, Wolfville, NS B4P 2R6, Canada
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402-6170, USA
| | - Wenfang Sun
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58108-6050, USA
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10
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Đokić M, Soo HS. Artificial photosynthesis by light absorption, charge separation, and multielectron catalysis. Chem Commun (Camb) 2018; 54:6554-6572. [DOI: 10.1039/c8cc02156b] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We highlight recent novel approaches in the field of artificial photosynthesis. We emphasize the potential of a highly modular plug-and-play concept that we hope will persuade the community to explore a more inclusive variety of multielectron redox catalysis to complement the proton reduction and water oxidation half-reactions in traditional solar water splitting systems.
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Affiliation(s)
- Miloš Đokić
- Division of Chemistry and Biological Chemistry
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore 637371
- Singapore
| | - Han Sen Soo
- Division of Chemistry and Biological Chemistry
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore 637371
- Singapore
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11
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Yersin H, Czerwieniec R, Shafikov MZ, Suleymanova AF. TADF Material Design: Photophysical Background and Case Studies Focusing on Cu I and Ag I Complexes. Chemphyschem 2017; 18:3508-3535. [PMID: 29083512 DOI: 10.1002/cphc.201700872] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Revised: 10/24/2017] [Indexed: 12/21/2022]
Abstract
The development of organic light emitting diodes (OLEDs) and the use of emitting molecules have strongly stimulated scientific research of emitting compounds. In particular, for OLEDs it is required to harvest all singlet and triplet excitons that are generated in the emission layer. This can be achieved using the so-called triplet harvesting mechanism. However, the materials to be applied are based on high-cost rare metals and therefore, it has been proposed already more than one decade ago by our group to use the effect of thermally activated delayed fluorescence (TADF) to harvest all generated excitons in the lowest excited singlet state S1 . In this situation, the resulting emission is an S1 →S0 fluorescence, though a delayed one. Hence, this mechanism represents the singlet harvesting mechanism. Using this effect, high-cost and strong SOC-carrying rare metals are not required. This mechanism can very effectively be realized by use of CuI or AgI complexes and even by purely organic molecules. In this investigation, we focus on photoluminescence properties and on crucial requirements for designing CuI and AgI materials that exhibit short TADF decay times at high emission quantum yields. The decay times should be as short as possible to minimize non-radiative quenching and, in particular, chemical reactions that frequently occur in the excited state. Thus, a short TADF decay time can strongly increase the material's long-term stability. Here, we study crucial parameters and analyze their impact on the TADF decay time. For example, the energy separation ΔE(S1 -T1 ) between the lowest excited singlet state S1 and the triplet state T1 should be small. Accordingly, we present detailed photophysical properties of two case-study materials designed to exhibit a large ΔE(S1 -T1 ) value of 1000 cm-1 (120 meV) and, for comparison, a small one of 370 cm-1 (46 meV). From these studies-extended by investigations of many other CuI TADF compounds-we can conclude that just small ΔE(S1 -T1 ) is not a sufficient requirement for short TADF decay times. High allowedness of the transition from the emitting S1 state to the electronic ground state S0 , expressed by the radiative rate kr (S1 →S0 ) or the oscillator strength f(S1 →S0 ), is also very important. However, mostly small ΔE(S1 -T1 ) is related to small kr (S1 →S0 ). This relation results from an experimental investigation of a large number of CuI complexes and basic quantum mechanical considerations. As a consequence, a reduction of τ(TADF) to below a few μs might be problematic. However, new materials can be designed for which this disadvantage is not prevailing. A new TADF compound, Ag(dbp)(P2 -nCB) (with dbp=2,9-di-n-butyl-1,10-phenanthroline and P2 -nCB=bis-(diphenylphosphine)-nido-carborane) seems to represent such an example. Accordingly, this material shows TADF record properties, such as short TADF decay time at high emission quantum yield. These properties are based (i) on geometry optimizations of the AgI complex for a fast radiative S1 →S0 rate and (ii) on restricting the extent of geometry reorganizations after excitation for reducing non-radiative relaxation and emission quenching. Indeed, we could design a TADF material with breakthrough properties showing τ(TADF)=1.4 μs at 100 % emission quantum yield.
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Affiliation(s)
- Hartmut Yersin
- University of Regensburg, Institute of Physical Chemistry, Universitätsstr. 31, 93053, Regensburg, Germany
| | - Rafal Czerwieniec
- University of Regensburg, Institute of Physical Chemistry, Universitätsstr. 31, 93053, Regensburg, Germany
| | - Marsel Z Shafikov
- University of Regensburg, Institute of Physical Chemistry, Universitätsstr. 31, 93053, Regensburg, Germany.,Ural Federal University, Mira 19, Ekaterinburg, 620002, Russia
| | - Alfiya F Suleymanova
- University of Regensburg, Institute of Physical Chemistry, Universitätsstr. 31, 93053, Regensburg, Germany.,I. Postovsky Institute of Organic Synthesis, Ekaterinburg, 620990, Russia
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12
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Hasan K, Wang J, Pal AK, Hierlinger C, Guerchais V, Sen Soo H, García F, Zysman-Colman E. Bay-Region Functionalisation of Ar-BIAN Ligands and Their Use Within Highly Absorptive Cationic Iridium(III) Dyes. Sci Rep 2017; 7:15520. [PMID: 29138392 PMCID: PMC5686200 DOI: 10.1038/s41598-017-14996-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 10/20/2017] [Indexed: 12/21/2022] Open
Abstract
We report the synthesis, UV-vis absorption, electrochemical characterisation, and DFT studies of five panchromatic, heteroleptic iridium complexes (four of which are new) supported by Ar-BIAN ligands. In particular, the synthesis of an ester-functionalised Ar-BIAN ligand was carried out by a mechanochemical milling approach, which was advantageous over conventional metal templating solution methods in terms of reaction time and product purity. The introduction of ester and carboxylate functionalities at the bay region of the acenaphthene motif increases each ligand’s π-accepting capacity and imparts grafting capabilities to the iridium complexes. These complexes have absorption profiles that surpass the renowned N3 dye [Ru(dcbpy)2(NCS)2] (dcbpy = 4,4′-dicarboxy-2,2′-bipyridine), making them of interest for solar-energy-harvesting applications.
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Affiliation(s)
- Kamrul Hasan
- Département de Chimie, Université de Sherbrooke, 2500 Boul. de l'Université, Sherbrooke, QC, J1K 2R1, Canada.,Department of Chemistry, College of Sciences, University of Sharjah, Sharjah, P. O. Box 27272, UAE
| | - Jingyi Wang
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Amlan K Pal
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK
| | - Claus Hierlinger
- Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK.,Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes 1, Campus de Beaulieu, 35042, Rennes Cedex, France
| | - Véronique Guerchais
- Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes 1, Campus de Beaulieu, 35042, Rennes Cedex, France
| | - Han Sen Soo
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore.,Solar Fuels Laboratory, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Felipe García
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Eli Zysman-Colman
- Département de Chimie, Université de Sherbrooke, 2500 Boul. de l'Université, Sherbrooke, QC, J1K 2R1, Canada. .,Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK.
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13
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Báez-Castro A, Baldenebro-López J, Cruz-Enríquez A, Höpfl H, Glossman-Mitnik D, Miranda-Soto V, Parra-Hake M, Reynoso-Soto E, Campos-Gaxiola JJ. Heteroleptic Cu(I) complexes containing polypyridyl ligands and triphenylphosphine: Synthesis, structure, photophysical properties, DFT studies and applications in co-sensitized solar cells. Inorganica Chim Acta 2017. [DOI: 10.1016/j.ica.2017.07.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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14
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Wang J, Ganguly R, Yongxin L, Díaz J, Soo HS, García F. Synthesis and the Optical and Electrochemical Properties of Indium(III) Bis(arylimino)acenaphthene Complexes. Inorg Chem 2017; 56:7811-7820. [DOI: 10.1021/acs.inorgchem.7b00539] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Jingyi Wang
- Division of Chemistry
and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Rakesh Ganguly
- Division of Chemistry
and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Li Yongxin
- Division of Chemistry
and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Jesus Díaz
- Departamento de
Química Orgánica e Inorgánica, Facultad de Veterinaria, Universidad de Extremadura, Cáceres 10071, Spain
| | - Han Sen Soo
- Division of Chemistry
and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
- Singapore-Berkeley Research Initiative for Sustainable Energy (SinBeRISE), 1
Create Way, 138602 Singapore
- Solar Fuels Laboratory, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
| | - Felipe García
- Division of Chemistry
and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
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15
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Báez-Castro A, Baldenebro-López J, Ceballos-Mendivil L, Román-Bravo PP, Höpfl H, Miranda-Soto V, Glossman-Mitnik D, Cruz-Enríquez A, Campos-Gaxiola JJ. Synthesis, crystal structure, DFT studies and photophysical properties of a copper(I)–triphenylphosphane complex based on trans-(±)-2,4,5-tris(pyridin-2-yl)-2-imidazoline. ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY 2017; 73:280-286. [DOI: 10.1107/s2053229617002522] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 02/14/2017] [Indexed: 11/10/2022]
Abstract
The possibility of using less expensive and nontoxic metals, such as copper, as substitutes for more expensive heavy metals in the synthesis of new transition-metal complexes to be used as sensitizers in dye-sensitized solar cells (DSSCs) has stimulated research in this field. The novel photoluminescent copper(I) complex bis(triphenylphosphane-κP)[trans-(±)-2,4,5-tris(pyridin-2-yl)-2-imidazoline-κ2
N
2,N
3]copper(I) hexafluorophosphate, [CuI(C18H15N5)(C18H15P)2]PF6, has been successfully synthesized and characterized by IR and 1H NMR spectroscopy, as well as by single-crystal X-ray diffraction and thermogravimetric analysis. The complex showed interesting photophysical properties, which were studied experimentally in solution and in the solid state by UV–Vis and fluorescence spectroscopy. Density functional theory (DFT) calculations with dichloromethane as solvent reproduced reasonably well the HOMO and LUMO orbitals of the title compound.
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16
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Czerwieniec R, Leitl MJ, Homeier HH, Yersin H. Cu(I) complexes – Thermally activated delayed fluorescence. Photophysical approach and material design. Coord Chem Rev 2016. [DOI: 10.1016/j.ccr.2016.06.016] [Citation(s) in RCA: 321] [Impact Index Per Article: 40.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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17
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Mei HX, Huang HQ, Zhang T, Huang RB, Zheng LS. Ag coordination compounds of a bifunctional diaminotriazine–imidazole ligand with various anions and solvents: Synthesis, structures, photoluminescence, and thermal properties. J Mol Struct 2016. [DOI: 10.1016/j.molstruc.2015.11.065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Kee JW, Ng YY, Kulkarni SA, Muduli SK, Xu K, Ganguly R, Lu Y, Hirao H, Soo HS. Development of bis(arylimino)acenaphthene (BIAN) copper complexes as visible light harvesters for potential photovoltaic applications. Inorg Chem Front 2016. [DOI: 10.1039/c5qi00221d] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Readily synthesized, new bis(arylimino)acenaphthene copper(i) complexes exhibit panchromatic light absorption to the NIR region and function in dye-sensitized solar cells.
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Affiliation(s)
- J. W. Kee
- Division of Chemistry and Biological Chemistry
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore 637371
| | - Y. Y. Ng
- Division of Chemistry and Biological Chemistry
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore 637371
| | - S. A. Kulkarni
- Energy Research Institute@NTU (ERI@N)
- Nanyang Technological University
- Singapore 637553
| | - S. K. Muduli
- Division of Chemistry and Biological Chemistry
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore 637371
- Energy Research Institute@NTU (ERI@N)
| | - K. Xu
- Division of Chemistry and Biological Chemistry
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore 637371
| | - R. Ganguly
- Division of Chemistry and Biological Chemistry
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore 637371
| | - Y. Lu
- Division of Chemistry and Biological Chemistry
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore 637371
| | - H. Hirao
- Division of Chemistry and Biological Chemistry
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore 637371
| | - H. S. Soo
- Division of Chemistry and Biological Chemistry
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore 637371
- Singapore-Berkeley Research Initiative for Sustainable Energy (SinBeRISE)
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19
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Czerwieniec R, Yersin H. Diversity of copper(I) complexes showing thermally activated delayed fluorescence: basic photophysical analysis. Inorg Chem 2015; 54:4322-7. [PMID: 25894718 DOI: 10.1021/ic503072u] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A comparison of three copper(I) compounds [1, Cu(dppb)(pz2Bph2); 2, Cu(pop)(pz2Bph2); 3, Cu(dmp)(phanephos)(+)] that show pronounced thermally activated delayed fluorescence (TADF) at ambient temperature demonstrates a wide diversity of emission behavior. In this study, we focus on compound 1. A computational density functional theory (DFT)/time-dependent DFT approach allows us to predict detailed photophysical properties, while experimental emission studies over a wide temperature range down to T = 1.5 K lead to better insight into the electronic structures even with respect to spin-orbit coupling efficiencies, radiative rates, and zero-field splitting of the triplet state. All three compounds, with emission quantum yields higher than ϕPL = 70%, are potentially well suited as emitters for organic light-emitting diodes (OLEDs) based on the singlet-harvesting mechanism. Interestingly, compound 1 is by far the most attractive one because of a very small energy separation between the lowest excited singlet S1 and triplet T1 state of ΔE(S1-T1) = 370 cm(-1) (46 meV). Such a small value has not been reported so far. It is responsible for the very short decay time of τ(TADF, 300 K) = 3.3 μs. Hence, if focused on the requirements of a short TADF decay time for reduction of the saturation effects in OLEDs, copper(I) complexes are well comparable or even slightly better than the best purely organic TADF emitters.
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Affiliation(s)
- Rafał Czerwieniec
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93053 Regensburg, Germany
| | - Hartmut Yersin
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93053 Regensburg, Germany
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20
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21
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Huang TH, Zhang MH. Novel copper(I) complexes with extended π⋯π interactions: Synthesis, structure, characterization and spectroscopic properties. Inorganica Chim Acta 2014. [DOI: 10.1016/j.ica.2014.03.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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22
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Huang TH, Zhang MH. Syntheses, Structures, Characterisation, and Spectroscopic Properties of CuI and AgI Complexes with Extended C–H···π and π···π Interactions. Aust J Chem 2014. [DOI: 10.1071/ch13566] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Based on the ligands N,N′-bis(pyridin-2-ylmethylene)benzene-1,4-diamine (pmb) and N,N′-bis(pyridin-2-ylmethylene)biphenyl-4,4′-diamine (pmbb), the three compounds [Cu2(pmb) (PPh3)2(Cl)2] (1), [Cu2(pmbb)(CH3CN)2(PPh3)2](BF4)2·2DMF (2), and [Ag2(pmbb)(PPh3)2] (ClO4)2 (3) have been synthesised and characterised. Structural analysis reveals that all of these complexes contain 1D supramolecular arrays, with different variations in π-stacking patterns and intermolecular C–H···π interactions. Crystal structures of 1 and 2 contain 1D tape-like arrays formed by C–H···π and π···π interactions, and an ordered-layer-lattice of DMF and BF4– in 2 is located between the one-dimensional array. For 3, π-stacking interactions lead to the construction of 1D supramolecular arrays and a 2D network. The results indicate that C–H···π and π···π interactions play an important role in the construction of the supramolecular structure. In addition, the absorption peaks of complexes 1 and 3 in the solid state at room temperature show intraligand charge transfer and metal-to-ligand charge transfer absorptions. The optical and fluorescent properties of 2 were also studied in acetonitrile solution at room temperature.
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23
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Báez-Castro A, Baldenebro-López J, Cruz-Enríquez A, Höpfl H, Glossman-Mitnik D, Valentín MS, Parra-Hake M, Campos-Gaxiola JJ. Synthesis, structure, characterization and photophysical properties of copper(i) complexes containing polypyridyl ligands. RSC Adv 2014. [DOI: 10.1039/c4ra06512c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Two novel photoluminescent copper(i) complexes have been successfully synthesized and characterized. Both complexes showed interesting photophysical properties.
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Affiliation(s)
- Alberto Báez-Castro
- Facultad de Ingeniería Mochis
- Universidad Autónoma de Sinaloa
- Fuente de Poseidón y Prol. A. Flores S/N
- C.U. Los Mochis, México
| | - Jesús Baldenebro-López
- Facultad de Ingeniería Mochis
- Universidad Autónoma de Sinaloa
- Fuente de Poseidón y Prol. A. Flores S/N
- C.U. Los Mochis, México
| | - Adriana Cruz-Enríquez
- Facultad de Ingeniería Mochis
- Universidad Autónoma de Sinaloa
- Fuente de Poseidón y Prol. A. Flores S/N
- C.U. Los Mochis, México
| | - Herbert Höpfl
- Centro de Investigaciones Químicas
- Universidad Autónoma del Estado de Morelos
- Av. Universidad 1001
- Cuernavaca, México
| | | | | | - Miguel Parra-Hake
- Centro de Graduados e Investigación
- Instituto Tecnológico de Tijuana
- Tijuana, México
| | - José J. Campos-Gaxiola
- Facultad de Ingeniería Mochis
- Universidad Autónoma de Sinaloa
- Fuente de Poseidón y Prol. A. Flores S/N
- C.U. Los Mochis, México
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Papanikolaou PA, Gdaniec M, Wicher B, Akrivos PD, Tkachenko NV. Bis(aryl)acenaphthenequinonediimine Substituent Effect on the Properties and Coordination Environment of Ligands and Their Bis-Chelate AgIComplexes. Eur J Inorg Chem 2013. [DOI: 10.1002/ejic.201300828] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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