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Rosenboom J, Taube F, Teichmeier L, Villinger A, Reinhard M, Demeshko S, Bennati M, Bresien J, Corzilius B, Schulz A. Rational Design of a Phosphorus-Centered Disbiradical. Angew Chem Int Ed Engl 2024; 63:e202318210. [PMID: 38117661 DOI: 10.1002/anie.202318210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 12/19/2023] [Accepted: 12/20/2023] [Indexed: 12/22/2023]
Abstract
Phosphorus-centered disbiradicals, in which the radical sites exist as individual spin doublets with weak spin-spin interaction have not been known so far. Starting from monoradicals of the type [⋅P(μ-NTer)2 P-R], we have now succeeded in linking two such monoradical phosphorus centers by appropriate choice of a linker. To this end, biradical [⋅P(μ-NTer)2 P⋅] (1) was treated with 1,6-dibromohexane, affording the brominated species {Br[P(μ-NTer)]2 }2 C6 H12 (3). Subsequent reduction with KC8 led to the formation of the disbiradical {⋅[P(μ-NTer)]2 }2 C6 H12 (4) featuring a large distance between the radical phosphorus sites in the solid state and formally the highest biradical character observed in a P-centered biradical so far, approaching 100 %. EPR spectroscopy revealed a three-line signal in solution with a considerably larger exchange interaction than would be expected from the molecular structure of the single crystal. Quantum chemical calculations revealed a highly dynamic conformational space; thus, the two radical sites can approach each other with a much smaller distance in solution. Further reduction of 4 resulted in the formation of a potassium salt featuring the first structurally characterized P-centered distonic radical anion (5- ). Moreover, 4 could be used in small molecule activation.
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Affiliation(s)
- Jan Rosenboom
- Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, 18059, Rostock, Germany
| | - Florian Taube
- Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, 18059, Rostock, Germany
| | - Leon Teichmeier
- Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, 18059, Rostock, Germany
| | - Alexander Villinger
- Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, 18059, Rostock, Germany
| | - Maik Reinhard
- Georg-August-Universität Göttingen, Tammannstr. 4/6, 37077, Göttingen, Germany
- MPINAT, Research Group ESR Spectroscopy, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Serhiy Demeshko
- Georg-August-Universität Göttingen, Tammannstr. 4/6, 37077, Göttingen, Germany
| | - Marina Bennati
- Georg-August-Universität Göttingen, Tammannstr. 4/6, 37077, Göttingen, Germany
- MPINAT, Research Group ESR Spectroscopy, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Jonas Bresien
- Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, 18059, Rostock, Germany
| | - Björn Corzilius
- Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, 18059, Rostock, Germany
- Leibniz-Institut für Katalyse e.V., Albert-Einstein-Straße 29a, 18059, Rostock, Germany
- Department Life, Light & Matter, Universität Rostock, Albert-Einstein-Straße 25, 18059, Rostock, Germany
| | - Axel Schulz
- Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, 18059, Rostock, Germany
- Leibniz-Institut für Katalyse e.V., Albert-Einstein-Straße 29a, 18059, Rostock, Germany
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Som A, Wehrenberg-Klee E, Rosenboom J, Chandler A, Ndakwah G, Kim J, Feig V, Marcos-Vidal A, Fintelmann F, Basu A, Langer R, Traverso G, Mahmood U. Abstract No. 4 ▪ FEATURED ABSTRACT Image-Guided Intratumoral Cancer Vaccine to Treat Metastatic Immunotherapy Resistant Cancer with and without Cryoablation. J Vasc Interv Radiol 2023. [DOI: 10.1016/j.jvir.2022.12.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023] Open
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Rosenboom J, Villinger A, Schulz A, Bresien J. Concerted addition of aldehydes to the singlet biradical [P(μ-NTer)] 2. Dalton Trans 2022; 51:13479-13487. [PMID: 35997123 DOI: 10.1039/d2dt02229j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction of the singlet biradical [P(μ-NTer)]2 with various aldehydes selectively yielded the corresponding [2.1.1]-bicyclic addition products in a very fast reaction. All products were fully characterized, including by NMR and vibrational spectroscopy as well as single-crystal X-ray diffraction. The mechanism of the addition was investigated theoretically using high-level ab initio methods (CCSD(T) with triple- and quadruple-zeta basis sets) and corresponds to a concerted cycloaddition reaction with a very low activation barrier. For comparison, the mechanisms of the literature-known cycloadditions of H2, alkenes, and alkynes were also studied, indicating a similar reaction profile for all unsaturated reactants.
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Affiliation(s)
- Jan Rosenboom
- Institute of Chemistry, University of Rostock, Albert-Einstein-Str. 3a, 18059 Rostock, Germany.
| | - Alexander Villinger
- Institute of Chemistry, University of Rostock, Albert-Einstein-Str. 3a, 18059 Rostock, Germany.
| | - Axel Schulz
- Institute of Chemistry, University of Rostock, Albert-Einstein-Str. 3a, 18059 Rostock, Germany. .,Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059 Rostock, Germany
| | - Jonas Bresien
- Institute of Chemistry, University of Rostock, Albert-Einstein-Str. 3a, 18059 Rostock, Germany.
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Rosenboom J, Chojetzki L, Suhrbier T, Rabeah J, Villinger A, Wustrack R, Bresien J, Schulz A. Radical Reactivity of the Biradical [⋅P(μ-NTer) 2 P⋅] and Isolation of a Persistent Phosphorus-Cantered Monoradical [⋅P(μ-NTer) 2 P-Et]. Chemistry 2022; 28:e202200624. [PMID: 35445770 PMCID: PMC9322606 DOI: 10.1002/chem.202200624] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Indexed: 11/06/2022]
Abstract
The activation of C-Br bonds in various bromoalkanes by the biradical [⋅P(μ-NTer)2 P⋅] (1) (Ter=2,6-bis-(2,4,6-trimethylphenyl)-phenyl) is reported, yielding trans-addition products of the type [Br-P(μ-NTer)2 P-R] (2), so-called 1,3-substituted cyclo-1,3-diphospha-2,4-diazanes. This addition reaction, which represents a new easy approach to asymmetrically substituted cyclo-1,3-diphospha-2,4-diazanes, was investigated mechanistically by different spectroscopic methods (NMR, EPR, IR, Raman); the results suggested a stepwise radical reaction mechanism, as evidenced by the in-situ detection of the phosphorus-centered monoradical [⋅P(μ-NTer)2 P-R].< To provide further evidence for the radical mechanism, [⋅P(μ-NTer)2 P-Et] (3Et⋅) was synthesized directly by reduction of the bromoethane addition product [Br-P(μ-NTer)2 P-Et] (2 a) with magnesium, resulting in the formation of the persistent phosphorus-centered monoradical [⋅P(μ-NTer)2 P-Et], which could be isolated and fully characterized, including single-crystal X-ray diffraction. Comparison of the EPR spectrum of the radical intermediate in the addition reaction with that of the synthesized new [⋅P(μ-NTer)2 P-Et] radical clearly proves the existence of radicals over the course of the reaction of biradical [⋅P(μ-NTer)2 P⋅] (1) with bromoethane. Extensive DFT and coupled cluster calculations corroborate the experimental data for a radical mechanism in the reaction of biradical [⋅P(μ-NTer)2 P⋅] with EtBr. In the field of hetero-cyclobutane-1,3-diyls, the demonstration of a stepwise radical reaction represents a new aspect and closes the gap between P-centered biradicals and P-centered monoradicals in terms of radical reactivity.
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Affiliation(s)
- Jan Rosenboom
- Institut für Chemie, Universität, Albert-Einstein-Straße 3a, 18059, Rostock, Germany
| | - Lukas Chojetzki
- Institut für Chemie, Universität, Albert-Einstein-Straße 3a, 18059, Rostock, Germany
| | - Tim Suhrbier
- Institut für Chemie, Universität, Albert-Einstein-Straße 3a, 18059, Rostock, Germany
| | - Jabor Rabeah
- Leibniz-Institut für Katalyse e.V., Albert-Einstein-Straße 29a, 18059, Rostock, Germany
| | - Alexander Villinger
- Institut für Chemie, Universität, Albert-Einstein-Straße 3a, 18059, Rostock, Germany
| | - Ronald Wustrack
- Institut für Chemie, Universität, Albert-Einstein-Straße 3a, 18059, Rostock, Germany
| | - Jonas Bresien
- Institut für Chemie, Universität, Albert-Einstein-Straße 3a, 18059, Rostock, Germany
| | - Axel Schulz
- Institut für Chemie, Universität, Albert-Einstein-Straße 3a, 18059, Rostock, Germany.,Leibniz-Institut für Katalyse e.V., Albert-Einstein-Straße 29a, 18059, Rostock, Germany
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