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Czernetzki C, Arrowsmith M, Endres L, Krummenacher I, Braunschweig H. Tricoordinate Beryllium Radicals and Their Reactivity. Inorg Chem 2024; 63:2670-2678. [PMID: 38259240 DOI: 10.1021/acs.inorgchem.3c04014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The one-electron reduction of [(CAAC)Be(Dur)Br] (CAAC = cyclic alkyl(amino)carbene, Dur = 2,3,5,6-tetramethylphenyl = duryl) with lithium sand in diethyl ether yields the first neutral, tricoordinate, and moderately stable beryllium radical, [(CAAC)(Et2O)BeDur]• (2-Et2O), which undergoes a facile second one-electron reduction concomitant with the insertion of the beryllium center into the endocyclic C-NCAAC bond and a cyclopropane-forming C-H bond activation of an adjacent methyl group. In situ generation of 2-Et2O and addition of PMe3 yield the stable analogue, [(CAAC)(Me3P)BeDur]• (2-PMe3), which serves as a platform for PMe3-ligand exchange with stronger donors, generating the radicals [(CAAC)LBeDur]• (2-L, L = isocyanides, pyridines, and N-heterocyclic carbenes). X-ray structural analyses show trigonal-planar beryllium centers and strong π backbonding from the metal to the CAAC ligand. The EPR signals of all six isolated [(CAAC)LBeDur]• radicals display significant, albeit small, hyperfine coupling to the 9Be nucleus. DFT calculations show that the spin density is mostly delocalized over the CAAC π framework and, where present, the isocyanide CN moiety, with only a small proportion (3-6%) on the beryllium center. 2-PMe3 proved thermally unstable at 80 °C, first undergoing radical hydrogen abstraction with the solvent, followed by insertion of beryllium into the endocyclic C-NCAAC bond and PMe3 transfer to the former carbene carbon atom. The reactions with diphenyl disulfide and phenyl azide occur at the beryllium center and yield the corresponding Be(II) phenyl sulfide and amino complexes, respectively, the latter concomitant with radical transfer and hydrogen abstraction by the beryllium-bound nitrogen center.
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Affiliation(s)
- Corinna Czernetzki
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
| | - Merle Arrowsmith
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
| | - Lukas Endres
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
| | - Ivo Krummenacher
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
| | - Holger Braunschweig
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, Würzburg 97074, Germany
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Langer D, Wicher B, Tykarska E. Single-crystal-to-single-crystal phase transition of 18β-glycyrrhetinic acid isopropyl ester. ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2022; 78:450-458. [PMID: 35702962 DOI: 10.1107/s2052520622002517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 03/04/2022] [Indexed: 06/15/2023]
Abstract
Due to the destruction of the integrity of the parent crystal, single-crystal-to-single-crystal phase transition in organic compounds is still a relatively rare phenomenon. The phase transition in glycyrrhetinic acid isopropyl ester is triggered by temperature change. The increasing volume of the isopropyl substituent as a result of increasing temperature forces a remodelling of the structural motifs. These changes cause a single-crystal-to-single-crystal phase transition. The low-temperature form is isostructural with glycyrrhetinic acid methanol solvate, while the high-temperature phase is isostructural with the ethyl ester of this acid.
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Affiliation(s)
- Dominik Langer
- Department of Chemical Technology of Drugs, Poznan University of Medical Sciences, Grunwladzka 6, Poznan 60-780, Poland
| | - Barbara Wicher
- Department of Chemical Technology of Drugs, Poznan University of Medical Sciences, Grunwladzka 6, Poznan 60-780, Poland
| | - Ewa Tykarska
- Department of Chemical Technology of Drugs, Poznan University of Medical Sciences, Grunwladzka 6, Poznan 60-780, Poland
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Zhou L, Li RX, Shi PP, Ye Q, Fu DW. Successive Phase Transitions and Dual Dielectric Switching in an Organic-Inorganic Hybrid Perovskite. Inorg Chem 2020; 59:18174-18180. [PMID: 33291874 DOI: 10.1021/acs.inorgchem.0c02649] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular phase transition compounds have become a hot research area in recent years because of their potential as functional materials, such as ferroelectrics, ferroelastics, dielectric switches, etc. However, materials combining switchable dielectric properties and ferroelasticity are still rare. Here, we reported an organic-inorganic hybrid perovskite, [CPtmp][Cd(SCN)3] (1) ([CPtmp]+ is a cyclopentyltrimethylphosphonium cation), with a potential ferroelastic property. This material undergoes three structural phase transitions at 247/226, 335/312, and 349/341 K (upon heating/cooling). The successive phase transitions are mainly caused by the stepwise ordering of [CPtmp]+ cations and the concomitant deformation of [Cd(SCN)3]- anionic chains revealed by structural analyses, which triggers the double-step dielectric switching in 1 as well. These results would inspire further exploration on molecular dielectric switches with ferroelastic properties.
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Affiliation(s)
- Lin Zhou
- Ordered Matter Science Research Center and Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China.,College of Chemistry, Nanchang University, Nanchang 330031, P. R. China
| | - Rui-Xia Li
- Ordered Matter Science Research Center and Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China
| | - Ping-Ping Shi
- Ordered Matter Science Research Center and Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China
| | - Qiong Ye
- Ordered Matter Science Research Center and Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China
| | - Da-Wei Fu
- Ordered Matter Science Research Center and Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China
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Reichel M, Unger C, Dubovnik S, Roidl A, Kornath A, Karaghiosoff K. Synthesis, structural and toxicological investigations of quarternary phosphonium salts containing the P-bonded bioisosteric CH 2F moiety. NEW J CHEM 2020. [DOI: 10.1039/d0nj02310h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Tertiary alkyl, aryl or amino phosphines PR3 (R = Me, nBu, C2H4CN, NEt2) and the bis[(2-diphenylphosphino)phenyl]ether (POP) were allowed to react with fluoroiodomethane to produce fluoromethyl phosphonium salts in yields between 60–99%.
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Affiliation(s)
- Marco Reichel
- Department Chemie
- Ludwig-Maximilian-Universität
- 81377 München
- Germany
| | - Cornelia Unger
- Department Chemie
- Ludwig-Maximilian-Universität
- 81377 München
- Germany
| | | | - Andreas Roidl
- Department Chemie
- Ludwig-Maximilian-Universität
- 81377 München
- Germany
| | - Andreas Kornath
- Department Chemie
- Ludwig-Maximilian-Universität
- 81377 München
- Germany
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