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Chiu WJ, Chu TY, Barve IJ, Sun CM. Parallel Synthesis of Pyrazolone-Fused Cinnolines by the Palladium-Catalyzed [4 + 2] Annulation of Pyrazol-3-ones with Substituted Allenoates. J Org Chem 2024; 89:395-401. [PMID: 38133555 DOI: 10.1021/acs.joc.3c02165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
The synthesis of pyrazolone-fused cinnolines from pyrazol-3-ones and α,γ-substituted allenoates via a palladium-catalyzed C-H activation/annulation cascade was developed. Mechanistic studies revealed the course of the reaction. Initially, N-acyl-valine ligand-assisted ortho-C-H activation gives ortho-alkenylated intermediate. Subsequent cyclopalladation and migratory insertion of allenoate give a seven-membered palladacycle. Reductive elimination finally furnishes pyrazolone-fused cinnolines.
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Affiliation(s)
- Wei-Jung Chiu
- Department of Applied Chemistry, National Yang-Ming Chiao-Tung University, 1001, Ta-Hseuh Road, Hsinchu 300-10, Taiwan
| | - Ting-Yen Chu
- Department of Applied Chemistry, National Yang-Ming Chiao-Tung University, 1001, Ta-Hseuh Road, Hsinchu 300-10, Taiwan
| | - Indrajeet J Barve
- Department of Chemistry, MES Abasaheb Garware College, Pune 411004, Maharashtra, India
| | - Chung-Ming Sun
- Department of Applied Chemistry, National Yang-Ming Chiao-Tung University, 1001, Ta-Hseuh Road, Hsinchu 300-10, Taiwan
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100, Shih-Chuan First Road, Kaohsiung 807-08, Taiwan
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Shekhovtsov NA, Vorob'eva S, Nikolaenkova EB, Ryadun AA, Krivopalov VP, Gourlaouen C, Bushuev MB. Complexes on the Base of a Proton Transfer Capable Pyrimidine Derivative: How Protonation and Deprotonation Switch Emission Mechanisms. Inorg Chem 2023; 62:16734-16751. [PMID: 37781777 DOI: 10.1021/acs.inorgchem.3c02036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
A rare example of pyrimidine-based ESIPT-capable compounds, 2-(2-hydroxyphenyl)-4-(1H-pyrazol-1-yl)-6-methylpyrimidine (HLH), was synthesized (ESIPT─excited state intramolecular proton transfer). Its reactions with zinc(II) salts under basic or acidic conditions afforded a dinuclear [Zn2LH2Cl2] complex and an ionic (H2LH)4[ZnCl4]2·3H2O solid. Another ionic solid, (H2LH)Br, was obtained from the solution of HLH acidified with HBr. In both ionic solids, the H+ ion protonates the same pyrimidinic N atom that accepts the O-H···N intramolecular hydrogen bond in the structure of free HLH, which breaks this hydrogen bond and switches off ESIPT in these compounds. This series of compounds which includes neutral HLH molecules and ionic (LH)- and (H2LH)+ species allowed us to elucidate the impact of protonation and coordination coupled deprotonation of HLH on the photoluminescence response and on altering the emission mechanism. The neutral HLH compound exhibits yellow emission as a result of the coexistence of two radiative decay channels: (i) T1 → S0 phosphorescence of the enol form and (ii) anti-Kasha S2 → S0 fluorescence of the keto form, which if feasible due to the large S2-S1 energy gap. However, owing to the efficient nonradiative decay through an energetically favorable conical intersection, the photoluminescence quantum yield of HLH is low. Protonation or deprotonation of the HLH ligand results in the significant blue-shift of the emission bands by more than 100 nm and boosts the quantum efficiency up to ca. 20% in the case of [Zn2LH2Cl2] and (H2LH)4[ZnCl4]2·3H2O. Despite both (H2LH)4[ZnCl4]2·3H2O and (H2LH)Br have the same (H2LH)+ cation in the structures, their emission properties differ significantly, whereas (H2LH)Br shows dual emission associated with two radiative decay channels: (i) S1 → S0 fluorescence and (ii) T1 → S0 phosphorescence, (H2LH)4[ZnCl4]2·3H2O exhibits only fluorescence. This difference in the emission properties can be associated with the external heavy atom effect in (H2LH)Br, which leads to faster intersystem crossing in this compound. Finally, a huge increase in the intensity of the phosphorescence of (H2LH)Br on cooling leads to pronounced luminescence thermochromism (violet emission at 300 K, sky-blue emission at 77 K).
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Affiliation(s)
- Nikita A Shekhovtsov
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk 630090, Russia
| | - Sofia Vorob'eva
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk 630090, Russia
| | - Elena B Nikolaenkova
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences, 9, Acad. Lavrentiev Ave., Novosibirsk 630090, Russia
| | - Alexey A Ryadun
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk 630090, Russia
| | - Viktor P Krivopalov
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences, 9, Acad. Lavrentiev Ave., Novosibirsk 630090, Russia
| | - Christophe Gourlaouen
- Laboratoire de Chimie Quantique, Institut de Chimie, UMR 7177 CNRS-Université de Strasbourg, 4 rue Blaise Pascal, Strasbourg Cedex 67070, France
| | - Mark B Bushuev
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk 630090, Russia
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Kokina TE, Shekhovtsov NA, Vasilyev ES, Glinskaya LA, Mikheylis AV, Plyusnin VF, Tkachev AV, Bushuev MB. Efficient emission of Zn(II) and Cd(II) complexes with nopinane-annelated 4,5-diazafluorene and 4,5-diazafluoren-9-one ligands: how slight structural modification alters fluorescence mechanism. Dalton Trans 2023. [PMID: 37183960 DOI: 10.1039/d3dt00904a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Zinc(II) and cadmium(II) chlorido complexes with an N,N-chelating nopinane-annelated 4,5-diazafluoren-9-one ligand (LO) were synthesized. While the zinc(II) complex is mononuclear and adopts a tetrahedral ZnN2Cl2 coordination geometry, its cadmium(II) analogue features a 1D polymeric structure due to the bridging coordination of chlorido ligands with Cd2+ ions having an octahedral CdN2Cl4 coordination geometry. The photophysical properties of the oxygen-containing LO ligand and its zinc(II) and cadmium(II) complexes were studied in solution and in the solid state and matched against the properties of its oxygen-free 4,5-diazafluorene congener L and its complexes of the same metal ions. Comprehensive experimental and theoretical studies revealed the impact of the oxygen atom in the ligand core on the luminescence of the ligands and the complexes. For the oxygen-free L ligand and L-based complexes, the structural differences between the S0 and S1 geometries are small, which leads to fluorescence with extraordinarily small Stokes shifts. The emission of these compounds is of locally excited character for L and of mixed locally excited + ligand-to-halide charge transfer character for the L-based complexes. The introduction of the oxygen atom in the ligand core results in a drastic red-shift of the emission band due to short-range charge transfer. The differences between the S0 and S1 geometries are much more pronounced for LO and LO-based compounds than those of their oxygen-free analogues, leading to an order of magnitude larger Stokes shifts. On going from solution to the solid state, LO and its complexes exhibit aggregation-induced emission (AIE) behaviour with photoluminescence quantum yields (PLQYs) reaching tens of percent.
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Affiliation(s)
- Tatyana E Kokina
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk, 630090, Russia.
| | - Nikita A Shekhovtsov
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk, 630090, Russia.
| | - Eugene S Vasilyev
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences, 9, Acad. Lavrentiev Ave., Novosibirsk, 630090, Russia.
| | - Ludmila A Glinskaya
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk, 630090, Russia.
| | - Aleksandr V Mikheylis
- Voevodsky Institute of Chemical Kinetics and Combustion, Siberian Branch of Russian Academy of Sciences, 3, Institutskaya str., Novosibirsk, 630090, Russia.
| | - Victor F Plyusnin
- Voevodsky Institute of Chemical Kinetics and Combustion, Siberian Branch of Russian Academy of Sciences, 3, Institutskaya str., Novosibirsk, 630090, Russia.
| | - Alexey V Tkachev
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences, 9, Acad. Lavrentiev Ave., Novosibirsk, 630090, Russia.
| | - Mark B Bushuev
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, 3, Acad. Lavrentiev Ave., Novosibirsk, 630090, Russia.
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Mustafa G, Zia-ur-Rehman M, Sumrra SH, Ashfaq M, Zafar W, Ashfaq M. A critical review on recent trends on pharmacological applications of pyrazolone endowed derivatives. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133044] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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