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John Arnold - One of the best experts on this subject based on the ideXlab platform.
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a uranium tri Rhenium triple inverse sandwich compound
Journal of the American Chemical Society, 2019Co-Authors: Trevor D Lohrey, Laurent Maron, John Arnold, Michael A. Boreen, David R. BrittAbstract:Salt metathesis between the anionic Rhenium(I) compound, Na[Re(η5-Cp)(BDI)] (BDI = N,N′-bis(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate), and the uranium(III) salt, UI3(1,4-dioxane)1.5, generated the triple inverse sandwich complex, U[(μ-η5:η5-Cp)Re(BDI)]3, which was isolated and structurally characterized as the Lewis base adducts, (L)U[(μ-η5:η5-Cp)Re(BDI)]3 (1·L, L = THF, 1,4-dioxane, DMAP). The assignment as one uranium(III) and three Rhenium(I) centers was supported by X-ray crystallography, NMR and EPR spectroscopies, and computational studies. An unusual shortening of the Rhenium–Cp bond distances in 1·L relative to Na[Re(η5-Cp)(BDI)] was observed in the solid-state and reproduced in calculated structures of 1·THF and the anionic fragment, [Re(η5-Cp)(BDI)]−. Calculations suggest that the electropositive uranium center pulls electron density away from the electron-rich Rhenium centers, reducing electron–electron repulsions in the Rhenium–Cp moieties and thereby strengthening those interactions...
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heterotetrametallic re zn zn re complex generated by an anionic Rhenium i β diketiminate
Journal of the American Chemical Society, 2019Co-Authors: Trevor D Lohrey, Laurent Maron, Robert G Bergman, John ArnoldAbstract:We report the synthesis of an anionic Rhenium(I) compound, Na[Re(η5-Cp)(BDI)] (1; Cp = cyclopentadienide, BDI = N,N′-bis(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate) and initial investigations of its use as a strong chemical reductant and metalloligand. Chemical oxidation of 1 gives a rare example of a Rhenium(II) compound Re(η5-Cp)(BDI) (2), while protonation of 1 yields the Rhenium(III) hydride complex Re(H)(η5-Cp)(BDI) (3). The reaction of 1 with ZnCl2 generated both 2 and the zinc(I) compound [ZnRe(η5-Cp)(BDI)]2 (4), which features a linear, tetrametallic Re(I)–Zn(I)–Zn(I)–Re(I) core. Computational studies of 4 were performed to characterize the metal–metal bonding interactions; the results indicate a dative interaction from Rhenium to zinc and covalent bonding between the two zinc centers. One-electron oxidation of 4 yielded both 2 and the triflate-bridged zinc(II) complex [(μ-OTf)ZnRe(η5-Cp)(BDI)]2 (5, OTf = trifluoromethanesulfonate).
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A Uranium Tri-Rhenium Triple Inverse Sandwich Compound
2019Co-Authors: Michael A. Boreen, Trevor D Lohrey, Laurent Maron, Guodong Rao, David R. Britt, John ArnoldAbstract:Salt metathesis between the anionic Rhenium(I) compound, Na[Re(η5-Cp)(BDI)] (BDI = N,N′-bis(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate), and the uranium(III) salt, UI3(1,4-dioxane)1.5, generated the triple inverse sandwich complex, U[(μ-η5:η5-Cp)Re(BDI)]3, which was isolated and structurally characterized as the Lewis base adducts, (L)U[(μ-η5:η5-Cp)Re(BDI)]3 (1·L, L = THF, 1,4-dioxane, DMAP). The assignment as one uranium(III) and three Rhenium(I) centers was supported by X-ray crystallography, NMR and EPR spectroscopies, and computational studies. An unusual shortening of the Rhenium–Cp bond distances in 1·L relative to Na[Re(η5-Cp)(BDI)] was observed in the solid-state and reproduced in calculated structures of 1·THF and the anionic fragment, [Re(η5-Cp)(BDI)]−. Calculations suggest that the electropositive uranium center pulls electron density away from the electron-rich Rhenium centers, reducing electron–electron repulsions in the Rhenium–Cp moieties and thereby strengthening those interactions, while also making uranium–Cp bonding more favorable
Giancarlo Pascali - One of the best experts on this subject based on the ideXlab platform.
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Rhenium(I) complexation–dissociation strategy for synthesising fluorine-18 labelled pyridine bidentate radiotracers
RSC Advances, 2020Co-Authors: Mitchell A. Klenner, Massimiliano Massi, Bo Zhang, Gianluca Ciancaleoni, James K. Howard, Helen E. Maynard-casely, Jack K. Clegg, Benjamin H. Fraser, Giancarlo PascaliAbstract:A novel fluorine-18 method employing Rhenium(I) mediation is described herein. The method was found to afford moderate to high radiochemical yields of labelled Rhenium(I) complexes. Subsequent thermal dissociation of the complexes enabled the radiosynthesis of fluorine-18 labelled pyridine bidentate structures which could not be radiofluorinated hitherto. This Rhenium(I) complexation–dissociation strategy was further applied to the radiosynthesis of [18F]CABS13, an Alzheimer's disease imaging agent, alongside other 2,2′-bipyridine, 1,10-phenanthroline and 8-hydroxyquinoline labelled radiotracers. Computational modelling of the reaction mechanism suggests that the efficiency of Rhenium(I) activation may be attributed to both an electron withdrawal effect by the metal center and the formation of an acyl fluoride intermediate which anchors the fluoride subsequent to nucleophilic addition.
Trevor D Lohrey - One of the best experts on this subject based on the ideXlab platform.
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a uranium tri Rhenium triple inverse sandwich compound
Journal of the American Chemical Society, 2019Co-Authors: Trevor D Lohrey, Laurent Maron, John Arnold, Michael A. Boreen, David R. BrittAbstract:Salt metathesis between the anionic Rhenium(I) compound, Na[Re(η5-Cp)(BDI)] (BDI = N,N′-bis(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate), and the uranium(III) salt, UI3(1,4-dioxane)1.5, generated the triple inverse sandwich complex, U[(μ-η5:η5-Cp)Re(BDI)]3, which was isolated and structurally characterized as the Lewis base adducts, (L)U[(μ-η5:η5-Cp)Re(BDI)]3 (1·L, L = THF, 1,4-dioxane, DMAP). The assignment as one uranium(III) and three Rhenium(I) centers was supported by X-ray crystallography, NMR and EPR spectroscopies, and computational studies. An unusual shortening of the Rhenium–Cp bond distances in 1·L relative to Na[Re(η5-Cp)(BDI)] was observed in the solid-state and reproduced in calculated structures of 1·THF and the anionic fragment, [Re(η5-Cp)(BDI)]−. Calculations suggest that the electropositive uranium center pulls electron density away from the electron-rich Rhenium centers, reducing electron–electron repulsions in the Rhenium–Cp moieties and thereby strengthening those interactions...
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heterotetrametallic re zn zn re complex generated by an anionic Rhenium i β diketiminate
Journal of the American Chemical Society, 2019Co-Authors: Trevor D Lohrey, Laurent Maron, Robert G Bergman, John ArnoldAbstract:We report the synthesis of an anionic Rhenium(I) compound, Na[Re(η5-Cp)(BDI)] (1; Cp = cyclopentadienide, BDI = N,N′-bis(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate) and initial investigations of its use as a strong chemical reductant and metalloligand. Chemical oxidation of 1 gives a rare example of a Rhenium(II) compound Re(η5-Cp)(BDI) (2), while protonation of 1 yields the Rhenium(III) hydride complex Re(H)(η5-Cp)(BDI) (3). The reaction of 1 with ZnCl2 generated both 2 and the zinc(I) compound [ZnRe(η5-Cp)(BDI)]2 (4), which features a linear, tetrametallic Re(I)–Zn(I)–Zn(I)–Re(I) core. Computational studies of 4 were performed to characterize the metal–metal bonding interactions; the results indicate a dative interaction from Rhenium to zinc and covalent bonding between the two zinc centers. One-electron oxidation of 4 yielded both 2 and the triflate-bridged zinc(II) complex [(μ-OTf)ZnRe(η5-Cp)(BDI)]2 (5, OTf = trifluoromethanesulfonate).
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A Uranium Tri-Rhenium Triple Inverse Sandwich Compound
2019Co-Authors: Michael A. Boreen, Trevor D Lohrey, Laurent Maron, Guodong Rao, David R. Britt, John ArnoldAbstract:Salt metathesis between the anionic Rhenium(I) compound, Na[Re(η5-Cp)(BDI)] (BDI = N,N′-bis(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate), and the uranium(III) salt, UI3(1,4-dioxane)1.5, generated the triple inverse sandwich complex, U[(μ-η5:η5-Cp)Re(BDI)]3, which was isolated and structurally characterized as the Lewis base adducts, (L)U[(μ-η5:η5-Cp)Re(BDI)]3 (1·L, L = THF, 1,4-dioxane, DMAP). The assignment as one uranium(III) and three Rhenium(I) centers was supported by X-ray crystallography, NMR and EPR spectroscopies, and computational studies. An unusual shortening of the Rhenium–Cp bond distances in 1·L relative to Na[Re(η5-Cp)(BDI)] was observed in the solid-state and reproduced in calculated structures of 1·THF and the anionic fragment, [Re(η5-Cp)(BDI)]−. Calculations suggest that the electropositive uranium center pulls electron density away from the electron-rich Rhenium centers, reducing electron–electron repulsions in the Rhenium–Cp moieties and thereby strengthening those interactions, while also making uranium–Cp bonding more favorable
Michael A. Boreen - One of the best experts on this subject based on the ideXlab platform.
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a uranium tri Rhenium triple inverse sandwich compound
Journal of the American Chemical Society, 2019Co-Authors: Trevor D Lohrey, Laurent Maron, John Arnold, Michael A. Boreen, David R. BrittAbstract:Salt metathesis between the anionic Rhenium(I) compound, Na[Re(η5-Cp)(BDI)] (BDI = N,N′-bis(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate), and the uranium(III) salt, UI3(1,4-dioxane)1.5, generated the triple inverse sandwich complex, U[(μ-η5:η5-Cp)Re(BDI)]3, which was isolated and structurally characterized as the Lewis base adducts, (L)U[(μ-η5:η5-Cp)Re(BDI)]3 (1·L, L = THF, 1,4-dioxane, DMAP). The assignment as one uranium(III) and three Rhenium(I) centers was supported by X-ray crystallography, NMR and EPR spectroscopies, and computational studies. An unusual shortening of the Rhenium–Cp bond distances in 1·L relative to Na[Re(η5-Cp)(BDI)] was observed in the solid-state and reproduced in calculated structures of 1·THF and the anionic fragment, [Re(η5-Cp)(BDI)]−. Calculations suggest that the electropositive uranium center pulls electron density away from the electron-rich Rhenium centers, reducing electron–electron repulsions in the Rhenium–Cp moieties and thereby strengthening those interactions...
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A Uranium Tri-Rhenium Triple Inverse Sandwich Compound
2019Co-Authors: Michael A. Boreen, Trevor D Lohrey, Laurent Maron, Guodong Rao, David R. Britt, John ArnoldAbstract:Salt metathesis between the anionic Rhenium(I) compound, Na[Re(η5-Cp)(BDI)] (BDI = N,N′-bis(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate), and the uranium(III) salt, UI3(1,4-dioxane)1.5, generated the triple inverse sandwich complex, U[(μ-η5:η5-Cp)Re(BDI)]3, which was isolated and structurally characterized as the Lewis base adducts, (L)U[(μ-η5:η5-Cp)Re(BDI)]3 (1·L, L = THF, 1,4-dioxane, DMAP). The assignment as one uranium(III) and three Rhenium(I) centers was supported by X-ray crystallography, NMR and EPR spectroscopies, and computational studies. An unusual shortening of the Rhenium–Cp bond distances in 1·L relative to Na[Re(η5-Cp)(BDI)] was observed in the solid-state and reproduced in calculated structures of 1·THF and the anionic fragment, [Re(η5-Cp)(BDI)]−. Calculations suggest that the electropositive uranium center pulls electron density away from the electron-rich Rhenium centers, reducing electron–electron repulsions in the Rhenium–Cp moieties and thereby strengthening those interactions, while also making uranium–Cp bonding more favorable
Mitchell A. Klenner - One of the best experts on this subject based on the ideXlab platform.
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Rhenium(I) complexation–dissociation strategy for synthesising fluorine-18 labelled pyridine bidentate radiotracers
RSC Advances, 2020Co-Authors: Mitchell A. Klenner, Massimiliano Massi, Bo Zhang, Gianluca Ciancaleoni, James K. Howard, Helen E. Maynard-casely, Jack K. Clegg, Benjamin H. Fraser, Giancarlo PascaliAbstract:A novel fluorine-18 method employing Rhenium(I) mediation is described herein. The method was found to afford moderate to high radiochemical yields of labelled Rhenium(I) complexes. Subsequent thermal dissociation of the complexes enabled the radiosynthesis of fluorine-18 labelled pyridine bidentate structures which could not be radiofluorinated hitherto. This Rhenium(I) complexation–dissociation strategy was further applied to the radiosynthesis of [18F]CABS13, an Alzheimer's disease imaging agent, alongside other 2,2′-bipyridine, 1,10-phenanthroline and 8-hydroxyquinoline labelled radiotracers. Computational modelling of the reaction mechanism suggests that the efficiency of Rhenium(I) activation may be attributed to both an electron withdrawal effect by the metal center and the formation of an acyl fluoride intermediate which anchors the fluoride subsequent to nucleophilic addition.
