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Esteruelas MA, Moreno-Blázquez S, Oliván M, Oñate E. Competition between N, C, N-Pincer and N, N-Chelate Ligands in Platinum(II). Inorg Chem 2023; 62:10152-10170. [PMID: 37343120 PMCID: PMC11003652 DOI: 10.1021/acs.inorgchem.3c00694] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Indexed: 06/23/2023]
Abstract
Replacement of the chloride ligand of PtCl{κ3-N,C,N-[py-C6HR2-py]} (R = H (1), Me (2)) and PtCl{κ3-N,C,N-[py-O-C6H3-O-py]} (3) by hydroxido gives Pt(OH){κ3-N,C,N-[py-C6HR2-py]} (R = H (4), Me (5)) and Pt(OH){κ3-N,C,N-[py-O-C6H3-O-py]} (6). These compounds promote deprotonation of 3-(2-pyridyl)pyrazole, 3-(2-pyridyl)-5-methylpyrazole, 3-(2-pyridyl)-5-trifluoromethylpyrazole, and 2-(2-pyridyl)-3,5-bis(trifluoromethyl)pyrrole. The coordination of the anions generates square-planar derivatives, which in solution exist as a unique species or equilibria between isomers. Reactions of 4 and 5 with 3-(2-pyridyl)pyrazole and 3-(2-pyridyl)-5-methylpyrazole provide Pt{κ3-N,C,N-[py-C6HR2-py]}{κ1-N1-[R'pz-py]} (R = H; R' = H (7), Me (8). R = Me; R' = H (9), Me (10)), displaying κ1-N1-pyridylpyrazolate coordination. A 5-trifluoromethyl substituent causes N1-to-N2 slide. Thus, 3-(2-pyridyl)-5-trifluoromethylpyrazole affords equilibria between Pt{κ3-N,C,N-[py-C6HR2-py]}{κ1-N1-[CF3pz-py]} (R = H (11a), Me (12a)) and Pt{κ3-N,C,N-[py-C6HR2-py]}{κ1-N2-[CF3pz-py]} (R = H (11b), Me (12b)). 1,3-Bis(2-pyridyloxy)phenyl allows the chelating coordination of the incoming anions. Deprotonations of 3-(2-pyridyl)pyrazole and its substituted 5-methyl counterpart promoted by 6 lead to equilibria between Pt{κ3-N,C,N-[pyO-C6H3-Opy]}{κ1-N1-[R'pz-py]} (R' = H (13a), Me (14a)) with a κ-N1-pyridylpyrazolate anion, keeping the pincer coordination of the di(pyridyloxy)aryl ligand, and Pt{κ2-N,C-[pyO-C6H3(Opy)]}{κ2-N,N-[R'pz-py]} (R' = H (13c), Me (14c)) with two chelates. Under the same conditions, 3-(2-pyridyl)-5-trifluoromethylpyrazole generates the three possible isomers: Pt{κ3-N,C,N-[pyO-C6H3-Opy]}{κ1-N1-[CF3pz-py]} (15a), Pt{κ3-N,C,N-[pyO-C6H3-Opy]}{κ1-N2-[CF3pz-py]} (15b), and Pt{κ2-N,C-[pyO-C6H3(Opy)]}{κ2-N,N-[CF3pz-py]} (15c). The N1-pyrazolate atom produces a remote stabilizing effect on the chelating form, pyridylpyrazolates being better chelate ligands than pyridylpyrrolates. Accordingly, reactions of 4-6 with 2-(2-pyridyl)-3,5-bis(trifluoromethyl)pyrrole yield Pt{κ3-N,C,N-[py-C6HR2-py]}{κ1-N1-[(CF3)2C4(py)HN]} (R = H (16), Me (17)) or Pt{κ3-N,C,N-[pyO-C6H3-Opy]}{κ1-N1-[(CF3)2C4(py)HN]} (18), displaying κ1-N1-pyrrolate coordination. Complexes 7-10 are efficient green phosphorescent emitters (488-576 nm). In poly(methyl methacrylate) (PMMA) films and in dichloromethane, they experience self-quenching, due to molecular stacking. Aggregation occurs through aromatic π-π interactions, reinforced by weak platinum-platinum interactions.
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Affiliation(s)
- Miguel A. Esteruelas
- Departamento de Química
Inorgánica, Instituto de Síntesis Química y Catálisis
Homogénea (ISQCH), Centro de Innovación en Química
Avanzada (ORFEO-CINQA), Universidad de Zaragoza—CSIC, 50009 Zaragoza, Spain
| | - Sonia Moreno-Blázquez
- Departamento de Química
Inorgánica, Instituto de Síntesis Química y Catálisis
Homogénea (ISQCH), Centro de Innovación en Química
Avanzada (ORFEO-CINQA), Universidad de Zaragoza—CSIC, 50009 Zaragoza, Spain
| | - Montserrat Oliván
- Departamento de Química
Inorgánica, Instituto de Síntesis Química y Catálisis
Homogénea (ISQCH), Centro de Innovación en Química
Avanzada (ORFEO-CINQA), Universidad de Zaragoza—CSIC, 50009 Zaragoza, Spain
| | - Enrique Oñate
- Departamento de Química
Inorgánica, Instituto de Síntesis Química y Catálisis
Homogénea (ISQCH), Centro de Innovación en Química
Avanzada (ORFEO-CINQA), Universidad de Zaragoza—CSIC, 50009 Zaragoza, Spain
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2
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Biller H, Strassner T. Synthesis and Physical Properties of Tunable Aryl Alkyl Ionic Liquids (TAAILs) Comprising Imidazolium Cations Blocked with Methyl-, Propyl- and Phenyl-Groups at the C2 Position. Chemistry 2023; 29:e202202795. [PMID: 36508719 PMCID: PMC10107658 DOI: 10.1002/chem.202202795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Indexed: 12/14/2022]
Abstract
Imidazolium-based ionic liquids are very popular for different applications because of their low viscosity and melting point. However, the hydrogen atom at the C2 position of the imidazolium cation can easily be deprotonated by a base, resulting in a reactive carbene. If an inert ionic liquid is needed, it is necessary to introduce an unreactive alkyl or aryl group at the C2 position to prevent deprotonation. Tunable aryl alkyl ionic liquids (TAAILs) were first introduced by our group in 2009 and are characterized by a phenyl group at the N1 position, which offers the possibility to fine-tune the physicochemical properties by using different electron-donating or -withdrawing substituents. In this work, we present a new series of TAAILs where the C2 position is blocked by a methyl, propyl or phenyl group. For each of the blocking groups, the phenyl and three different phenyl derivatives (2-Me, 4-OMe, 2,4-F2 ) are compared with respect to melting point, viscosity, conductivity and electrochemical window. In addition, the differences between blocked and unblocked TAAILs with regard to their electrochemical reduction potentials are investigated by quantum chemical methods.
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Affiliation(s)
- Harry Biller
- Physikalische Organische Chemie, Technische Universität Dresden, Bergstrasse 66, 01069, Dresden, Germany
| | - Thomas Strassner
- Physikalische Organische Chemie, Technische Universität Dresden, Bergstrasse 66, 01069, Dresden, Germany
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3
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Strassner NM, Stipurin S, Koželj P, Grin Y, Strassner T. Electronic Structure and Magnetic Properties of a High-Spin Mn III Complex: [Mn(mesacac) 3 ] (mesacac=1,3-Bis(2,4,6-trimethylphenyl)-propane-1,3-dionato). Chemphyschem 2023; 24:e202200652. [PMID: 36515278 PMCID: PMC10107892 DOI: 10.1002/cphc.202200652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 09/22/2022] [Indexed: 12/15/2022]
Abstract
Metal acetylacetonates of the general formula [M(acac)3 ] (MIII =Cr, Mn, Fe, Co) are among the best investigated coordination compounds. Many of these first-row transition metal complexes are known to have unique electronic properties. Independently, photophysical research with different β-diketonate ligands pointed towards the possibility of a special effect of the 2,4,6-trimethylphenyl substituted acetylacetonate (mesacac) on the electron distribution between ligand and metal (MLCT). We therefore synthesized and fully characterized the previously unknown octahedral title complex. Its solid-state structure shows a Jahn-Teller elongation with two Mn-O bonds of 2.12/2.15 Å and four Mn-O bonds of 1.93 Å. Thermogravimetric data show a thermal stability up to 270 °C. High-resolution mass spectroscopy helped to identify the decomposition pathways. The electronic state and spin configuration of manganese were characterized with a focus on its magnetic properties by measurement of the magnetic susceptibility and triple-zeta density functional theory (DFT) calculations. The high-spin state of manganese was confirmed by the determination of an effective magnetic moment of 4.85 μB for the manganese center.
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Affiliation(s)
- Nina M Strassner
- Department of Chemistry and Pharmacy, Friedrich-Alexander-University Erlangen-Nuremberg, 91054, Erlangen, Germany
| | - Sergej Stipurin
- Faculty of Chemistry and Food Chemistry, Physical Organic Chemistry, Technical University Dresden, 01062, Dresden, Germany
| | - Primož Koželj
- Max-Planck-Institute for Chemical Physics of Solids, 01187, Dresden, Germany
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia
| | - Yuri Grin
- Max-Planck-Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - Thomas Strassner
- Faculty of Chemistry and Food Chemistry, Physical Organic Chemistry, Technical University Dresden, 01062, Dresden, Germany
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4
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Vivancos Á, Bautista D, González-Herrero P. Phosphorescent Tris-cyclometalated Pt(IV) Complexes with Mesoionic N-Heterocyclic Carbene and 2-Arylpyridine Ligands. Inorg Chem 2022; 61:12033-12042. [PMID: 35860839 PMCID: PMC9377419 DOI: 10.1021/acs.inorgchem.2c02039] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The synthesis, structure, photophysical properties, and electrochemistry of the first series of Pt(IV) tris-chelates bearing cyclometalated aryl-NHC ligands are reported. The complexes have the general formula [Pt(trz)2(C∧N)]+, combining two units of the cyclometalated, mesoionic aryl-NHC ligand 4-butyl-3-methyl-1-phenyl-1H-1,2,3-triazol-5-ylidene (trz) with a cyclometalated 2-arylpyridine [C∧N = 2-(2,4-difluorophenyl)pyridine (dfppy), 2-phenylpyridine (ppy), 2-(p-tolyl)pyridine (tpy), 2-(2-thienyl)pyridine (thpy), 2-(9,9-dimethylfluoren-2-yl)pyridine (flpy)], and presenting a mer arrangement or metalated aryls. They exhibit a significant photostability under UV irradiation and long-lived phosphorescence in the blue to yellow color range, arising from 3LC excited states involving the C∧N ligands, with quantum yields of up to 0.34 in fluid solution and 0.77 in the rigid matrix at 298 K. The time-dependent density functional theory (TD-DFT) calculations reveal that nonemissive, deactivating excited states of ligand-to-metal charge-transfer (LMCT) character are pushed to high energies as a consequence of the strong σ-donating ability of the carbenic moieties, making the Pt(trz)2 subunit an essential structural component that enables efficient emissions from the chromophoric C∧N ligands, with potential application for the development of different Pt(IV) emitters with tunable properties.
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Affiliation(s)
- Ángela Vivancos
- Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, 19, 30100 Murcia, Spain
| | - Delia Bautista
- Área Científica y Técnica de Investigación, Universidad de Murcia, Campus de Espinardo, 21, 30100 Murcia, Spain
| | - Pablo González-Herrero
- Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, 19, 30100 Murcia, Spain
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Stipurin S, Wurl F, Strassner T. C∧C* Platinum(II) Complexes with PtXPX Metallacycle Forming (X = N and S) Auxiliary Ligands: Synthesis, Crystal Structures, and Properties. Organometallics 2022. [DOI: 10.1021/acs.organomet.1c00655] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sergej Stipurin
- Physikalische Organische Chemie, Technische Universität Dresden, 01069 Dresden, Germany
| | - Felix Wurl
- Physikalische Organische Chemie, Technische Universität Dresden, 01069 Dresden, Germany
| | - Thomas Strassner
- Physikalische Organische Chemie, Technische Universität Dresden, 01069 Dresden, Germany
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6
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Pinter P, Soellner J, Strassner T. Metallophilic Interactions in Bimetallic Cyclometalated Platinum(II) N‐Heterocyclic Carbene Complexes. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100456] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Piermaria Pinter
- Physikalische Organische Chemie Technische Universität Dresden 01069 Dresden Germany
| | - Johannes Soellner
- Physikalische Organische Chemie Technische Universität Dresden 01069 Dresden Germany
| | - Thomas Strassner
- Physikalische Organische Chemie Technische Universität Dresden 01069 Dresden Germany
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7
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Haque A, El Moll H, Alenezi KM, Khan MS, Wong WY. Functional Materials Based on Cyclometalated Platinum(II) β-Diketonate Complexes: A Review of Structure-Property Relationships and Applications. MATERIALS 2021; 14:ma14154236. [PMID: 34361430 PMCID: PMC8347388 DOI: 10.3390/ma14154236] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 07/21/2021] [Accepted: 07/26/2021] [Indexed: 11/24/2022]
Abstract
Square planar organoplatinum(II) complexes have garnered immense interest in the area of materials research. The combination of the Pt(II) fragment with mono-, bi- tri- and tetradentate organic ligands gives rise to a large variety of complexes with intriguing properties, especially cyclometalated Pt(II) complexes in which ligands are connected through covalent bonds demonstrate higher stability, excellent photoluminescence properties, and diverse applications. The properties and applications of the Pt(II)-based materials can be smartly fine-tuned via a judicious selection of the cyclometalating as well as ancillary ligands. In this review, attempts have been made to provide a brief review of the recent developments of neutral Pt(II) organometallic complexes bearing bidentate cyclometalating ligands and β-diketonate ancillary ligands, i.e., (C^N)Pt(O^O) and (C^C)Pt(O^O) derivatives. Both small (monomeric, dimeric) and large (polymeric) materials have been considered. We critically assessed the role of functionalities (ligands) on photophysical properties and their impact on applications.
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Affiliation(s)
- Ashanul Haque
- Department of Chemistry, College of Science, University of Hail, Ha’il 81451, Saudi Arabia; (H.E.M.); (K.M.A.)
- Correspondence: (A.H.); (M.S.K.); (W.-Y.W.)
| | - Hani El Moll
- Department of Chemistry, College of Science, University of Hail, Ha’il 81451, Saudi Arabia; (H.E.M.); (K.M.A.)
| | - Khalaf M. Alenezi
- Department of Chemistry, College of Science, University of Hail, Ha’il 81451, Saudi Arabia; (H.E.M.); (K.M.A.)
| | - Muhammad S. Khan
- Department of Chemistry, Sultan Qaboos University, P.O. Box 36, Al-Khod 123, Oman
- Correspondence: (A.H.); (M.S.K.); (W.-Y.W.)
| | - Wai-Yeung Wong
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
- Correspondence: (A.H.); (M.S.K.); (W.-Y.W.)
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8
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Vivancos Á, Jiménez-García A, Bautista D, González-Herrero P. Strongly Luminescent Pt(IV) Complexes with a Mesoionic N-Heterocyclic Carbene Ligand: Tuning Their Photophysical Properties. Inorg Chem 2021; 60:7900-7913. [PMID: 33970000 PMCID: PMC8893362 DOI: 10.1021/acs.inorgchem.1c00410] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Indexed: 12/18/2022]
Abstract
The synthesis, electrochemistry, and photophysical properties of a series of bis-cyclometalated Pt(IV) complexes that combine the mesoionic aryl-NHC ligand 4-butyl-3-methyl-1-phenyl-1H-1,2,3-triazol-5-ylidene (trz) with either 1-phenylpyrazole or 2-arylpyridine (C∧N) are reported. The complexes (OC-6-54)-[PtCl2(C∧N)(trz)] bearing cyclometalating 2-arylpyridines present phosphorescent emissions in the blue to yellow color range, which essentially arise from 3LC(C∧N) states, and reach quantum yields of ca. 0.3 in fluid solutions and almost unity in poly(methyl methacrylate) (PMMA) matrices at 298 K, thus representing a class of strong emitters with tunable properties. A systematic comparison with the homologous C2-symmetrical species (OC-6-33)-[PtCl2(C∧N)2], which contains two equal 2-arylpyridine ligands, shows that the introduction of a trz ligand leads to significantly lower nonradiative decay rates and higher quantum efficiencies. Computational calculations substantiate the effect of the carbene ligand, which raises the energy of dσ* orbitals in these derivatives and results in the higher energies of nonemissive deactivating 3LMCT states. In contrast, the isomers (OC-6-42)-[PtCl2(C∧N)(trz)] are not luminescent because they present a 3LMCT state as the lowest triplet.
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Affiliation(s)
- Ángela Vivancos
- Departamento
de Química Inorgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo 19, 30100 Murcia, Spain
| | - Adrián Jiménez-García
- Departamento
de Química Inorgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo 19, 30100 Murcia, Spain
| | - Delia Bautista
- Área
Científica y Técnica de Investigación, Universidad de Murcia, Campus de Espinardo, 21, 30100 Murcia, Spain
| | - Pablo González-Herrero
- Departamento
de Química Inorgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo 19, 30100 Murcia, Spain
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9
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Stipurin S, Strassner T. Phosphorescent Cyclometalated Platinum(II) Imidazolinylidene Complexes. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202001077] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Sergej Stipurin
- Physikalische Organische Chemie Technische Universität Dresden 01069 Dresden Germany
| | - Thomas Strassner
- Physikalische Organische Chemie Technische Universität Dresden 01069 Dresden Germany
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10
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Non-covalent intramolecular interactions through ligand-design promoting efficient photoluminescence from transition metal complexes. Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2019.213094] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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11
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Hutchinson SM, Ardón-Muñoz LG, Ratliff ML, Bolliger JL. Catalytic Preparation of 1-Aryl-Substituted 1,2,4-Triazolium Salts. ACS OMEGA 2019; 4:17923-17933. [PMID: 31681902 PMCID: PMC6822220 DOI: 10.1021/acsomega.9b03109] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Accepted: 10/09/2019] [Indexed: 05/10/2023]
Abstract
1,4-Diaryl- and 1-aryl-4-alkyl-substituted 1,2,4-triazolium salts are convenient air-stable precursors to carbenes used both as organocatalysts or as ligands for transition metal complexes. Traditionally, they are prepared via a multistep synthetic pathway with the low-yielding formation of the triazolium ring occurring in the last step. We have developed an alternative two-step synthesis involving the conversion of a primary amine or aniline derivative to the corresponding 4-substituted triazole followed by a copper-catalyzed arylation with diaryliodonium salts. This transition metal-catalyzed arylation can be carried out under mild conditions in acetonitrile and is tolerant toward both water and oxygen. Additionally, the high functional group tolerance of the protocol described here gives easy access to triazolium salts containing heterocyclic substituents or sulfides.
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12
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Pinter P, Strassner T. Prediction of emission wavelengths of phosphorescent NHC based emitters for OLEDs. Tetrahedron 2019. [DOI: 10.1016/j.tet.2019.06.039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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Soellner J, Strassner T. Cyclometalated Platinum(II) Complexes with Mesoionic Dibenzofuranyl‐1,2,3‐triazol‐4‐ylidene Ligands: Synthesis, Characterization and Photophysical Properties. CHEMPHOTOCHEM 2019. [DOI: 10.1002/cptc.201900083] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Johannes Soellner
- Physikalische Organische ChemieTechnische Universität Dresden 01069 Dresden Germany) Fax: (+49)351-463-39679
| | - Thomas Strassner
- Physikalische Organische ChemieTechnische Universität Dresden 01069 Dresden Germany) Fax: (+49)351-463-39679
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