1
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Ott A, Nagy PR, Benkő Z. Stability of Carbocyclic Phosphinyl Radicals: Effect of Ring Size, Delocalization, and Sterics. Inorg Chem 2022; 61:16266-16281. [PMID: 36197796 PMCID: PMC9583709 DOI: 10.1021/acs.inorgchem.2c01968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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In this computational study, we report on the stability
of cyclic
phosphinyl radicals with an aim for a systematical assessment of stabilization
effects. The radical stabilization energies (RSEs) were calculated
using isodesmic reactions for a large number of carbocyclic radicals
possessing different ring sizes and grades of unsaturation. In general,
the RSE values range from −1.2 to −14.0 kcal·mol–1, and they show practically no correlation with the
spin populations at the P-centers. The RSE values correlate with the
reaction Gibbs free energies calculated for the dimerization of the
studied simple radicals. Therefore, the more easily accessible RSE
values offer a cost-effective estimation of global stability in a
straightforward manner. To explore the effect of unsaturation on the
RSE values, delocalization energies were determined using appropriate
isodesmic reactions. Introducing unsaturations beside the P-center
into the backbone of the rings leads to an additive increase in the
magnitude of the delocalization energy (∼10, 20, and 30 kcal·mol–1, respectively, for radicals with one, two, and three
C=C bonds in the conjugation). Parallelly, the spin populations
at the P-centers also dwindle gradually by ∼0.1 e in the same
order, indicating that the lone electron delocalizes over the π-system.
Radicals containing exocyclic C=C π-bonds were also investigated,
and all of these radicals have rather similar stabilities independently
of the ring size, outlining the primary importance of the two exocyclic
π-bonds in the conjugation. Among the radicals involved in our
study, those with the best electronic stabilization are the unsaturated
three-, five-, six-, and seven-membered rings containing the maximum
number of conjugated vinyl fragments. The largest delocalization energy
of 31.5 kcal·mol–1 and the lowest obtained
spin population of 0.665 e were found for the fully unsaturated seven-membered
radical (phosphepin derivative). Importantly, the electronic stabilization
effects alone are insufficient for stabilizing the radicals in monomeric
forms epitomized by the exothermic dimerization energies (−40
to −58 kcal·mol–1). Therefore, it is
essential to apply sterically demanding bulky substituents on the
α-C-atoms. Tweaking the steric congestion enabled us to propose
radicals that are expected to be stable against dimerization and,
consequently, may be realistic target species for synthetic investigations.
The effects contributing to the stability of radicals having sterically
encumbered substituents have also been explored. To systematically evaluate the stabilization
effects, the
radical stabilization energies of various carbocyclic phosphinyl radicals
having saturated backbones or unsaturation(s) in either endocyclic
or exocyclic manner have been determined and analyzed. As the electronic
stabilization is alone insufficient to hamper the possible dimerization
of these species, the effect of several sterically demanding substituents
has been explored for the congeners with best electronic stabilizations,
thus enabling us to propose synthetically accessible candidates in
the future.
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Affiliation(s)
- Anna Ott
- Department of Inorganic and Analytical Chemistry, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
| | - Péter R Nagy
- Department of Physical Chemistry and Materials Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary.,ELKH-BME Quantum Chemistry Research Group, Műegyetem rkp. 3, H-1111 Budapest, Hungary
| | - Zoltán Benkő
- Department of Inorganic and Analytical Chemistry, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary.,ELKH-BME Computation Driven Chemistry Research Group, Műegyetem rkp. 3, H-1111 Budapest, Hungary
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2
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Volk N, Malik P, Alcaraz AG, Espinosa Ferao A, Streubel R. Chemistry of oxaphosphirane complexes. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.213818] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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3
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García Alcaraz A, Espinosa Ferao A, Streubel R. Azaphosphiridines: challenges and perspectives. Dalton Trans 2021; 50:7324-7336. [PMID: 33956019 DOI: 10.1039/d1dt01174j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
This mini-review describes a broad spectrum of synthetic strategies to access mono- and polycyclic azaphosphiridines; properties and theoretical calculations of free and metal-ligated are discussed. These species are characterized by a highly strained (saturated) CPN ring with three differently polarized endocyclic bonds. The latter causes a high reactivity of aza-phosphiridine complexes towards ring expansion and exchange reactions. Increasing the ring strain leads to masked FLP behaviour, i.e., small molecule activation was observed. New perspectives in homogenous catalysis are also offered, e.g., a pool of novel chiral P-heterocyclic ligands, ready to be explored, if the challenge to unligate them is solved.
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Affiliation(s)
- Antonio García Alcaraz
- Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain.
| | - Arturo Espinosa Ferao
- Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain.
| | - Rainer Streubel
- Institut für Anorganische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhards-Domagk-Str. 1, 53121 Bonn, Germany.
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4
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Espinosa Ferao A, Rey Planells A, Streubel R. Between Oxirane and Phosphirane: The Spring‐loaded Oxaphosphirane Ring. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000881] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Arturo Espinosa Ferao
- Department of Organic Chemistry Faculty of Chemistry University of Murcia Campus de Espinardo 30100 Murcia
| | - Alicia Rey Planells
- Department of Organic Chemistry Faculty of Chemistry University of Murcia Campus de Espinardo 30100 Murcia
| | - Rainer Streubel
- Institute of Inorganic Chemistry Rheinische Friedrich-Wilhelms-Universität Bonn Gerhard-Domagk-Straße 1
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5
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Espinosa Ferao A, García Alcaraz A, Zaragoza Noguera S, Streubel R. Terminal Phosphinidene Complex Adducts with Neutral and Anionic O-Donors and Halides and the Search for a Differentiating Bonding Descriptor. Inorg Chem 2020; 59:12829-12841. [DOI: 10.1021/acs.inorgchem.0c01874] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Arturo Espinosa Ferao
- Departamento de Quı́mica Orgánica, Facultad de Quı́mica, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain
| | - Antonio García Alcaraz
- Departamento de Quı́mica Orgánica, Facultad de Quı́mica, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain
| | - Salvador Zaragoza Noguera
- Departamento de Quı́mica Orgánica, Facultad de Quı́mica, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain
| | - Rainer Streubel
- Institut für Anorganische Chemie, Rheinischen Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
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6
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Espinosa Ferao A, Streubel R. A Computational Study on the Stability of Oxaphosphirane Rings towards Closed-Shell Valence Isomerization. Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201700177] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Arturo Espinosa Ferao
- Departamento de Química Orgánica; Facultad de Química; Universidad de Murcia; Campus de Espinardo 30100 Murcia Spain
| | - Rainer Streubel
- Institut für Anorganische Chemie; Rheinischen Friedrich-Wilhelms-Universität Bonn; Gerhardt-Domagk-Strasse 1 53121 Bonn Germany
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7
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Espinosa Ferao A, Streubel R. Coordination of N2
and Other Small Molecules to the Phosphorus Centre of RPW(CO)5
: A Theoretical Study on the Janus Facets of the Stabilization/Activation Problem. Chemistry 2017; 23:8632-8643. [DOI: 10.1002/chem.201700524] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Indexed: 11/12/2022]
Affiliation(s)
- Arturo Espinosa Ferao
- Departamento de Química Orgánica, Facultad de Química; Universidad de Murcia; Campus de Espinardo 30100 Murcia Spain
| | - Rainer Streubel
- Institut für Anorganische Chemie; Rheinischen Friedrich-Wilhelms-Universität Bonn; Gerhardt-Domagk-Strasse 1 53121 Bonn Germany
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8
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Espinosa Ferao A, Streubel R. Thiaphosphiranes and Their Complexes: Systematic Study on Ring Strain and Ring Cleavage Reactions. Inorg Chem 2016; 55:9611-9619. [PMID: 27618483 DOI: 10.1021/acs.inorgchem.6b01322] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Arturo Espinosa Ferao
- Departamento
de Química Orgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo 30100 Murcia, Spain
| | - Rainer Streubel
- Institut für Anorganische Chemie der Rheinischen Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany
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9
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García CM, Ferao AE, Schnakenburg G, Streubel R. CPh3 as a functional group in P-heterocyclic chemistry: elimination of HCPh3 in the reaction of P-CPh3 substituted Li/Cl phosphinidenoid complexes with Ph2CO. Dalton Trans 2016; 45:2378-85. [DOI: 10.1039/c5dt04595a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Li/Cl phosphinidenoid complexes 2a–c react with benzaldehyde to give 3a–c, but with benzophenone formation of complexes 4 and 5 was observed, the latter revealing the elimination of HCPh3.
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Affiliation(s)
- C. Murcia García
- Institut für Anorganische Chemie
- Rheinische Friedrich-Wilhelms-Universität Bonn
- D-53121 Bonn
- Germany
| | - A. Espinosa Ferao
- Departamento de Química Orgánica
- Facultad de Química
- Universidad de Murcia
- E-30071 Murcia
- Spain
| | - G. Schnakenburg
- Institut für Anorganische Chemie
- Rheinische Friedrich-Wilhelms-Universität Bonn
- D-53121 Bonn
- Germany
| | - R. Streubel
- Institut für Anorganische Chemie
- Rheinische Friedrich-Wilhelms-Universität Bonn
- D-53121 Bonn
- Germany
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10
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Streubel R, Murcia-García C, Schnakenburg G, Espinosa Ferao A. Evidence for Terminal Phosphinidene Oxide Complexes in O,P,C-Cage Complex Formation: Rearrangement of Oxaphosphirane Complexes. Organometallics 2015. [DOI: 10.1021/acs.organomet.5b00029] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rainer Streubel
- Institut
für Anorganische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, D-53121 Bonn, Germany
| | - Cristina Murcia-García
- Institut
für Anorganische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, D-53121 Bonn, Germany
| | - Gregor Schnakenburg
- Institut
für Anorganische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Straße 1, D-53121 Bonn, Germany
| | - Arturo Espinosa Ferao
- Departamento
de Química Orgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, E-30100 Murcia, Spain
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11
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Espinosa A, de las Heras E, Streubel R. Oxaphosphirane-Borane Complexes: Ring Strain and Migratory Insertion/Ring-Opening Reactions. Inorg Chem 2014; 53:6132-40. [PMID: 24902079 DOI: 10.1021/ic500536h] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Arturo Espinosa
- Departamento
de Química Orgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain
| | - Edgar de las Heras
- Departamento
de Química Orgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain
| | - Rainer Streubel
- Institut für Anorganische Chemie der Rheinischen Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Str.
1, 53121 Bonn, Germany
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12
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Garner EB, Arduengo AJ, Streubel R, Dixon DA. Electronic structure predictions of the properties of non-innocent P-ligands in group 6B transition metal complexes. Dalton Trans 2014; 43:2069-78. [PMID: 24285004 DOI: 10.1039/c3dt52056k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Neutral group 6B (Cr, Mo, W) pentacarbonyl complexes M(CO)5-L possessing various P-ligands such as phosphines, phosphaalkenes, and phospha-quinomethanes can form radical cations and anions under redox conditions. There is significant interest in whether the radical site is localized on the metal or on a "non-innocent" ligand. Density functional theory was used to predict whether the radicals of the complexes behave as metal or ligand-centered radicals and whether these compounds could form in solution or as an ion pair with various oxidizing and reducing agents. The quinone-like ligands are predicted to be ligand centered radicals when they are anions and metal centered radicals when they are cations. The predicted reaction energies for single electron transfer (SET) reactions involving the quinone like ligands are negative or near thermoneutral for both radicals in polar solutions and as solid state ion pairs. The energetics of the SET reactions can be controlled by the nature of L, the nature of the oxidizing/reducing agent, and the solvent polarity. Such complexes could be used as flexible catalysts for single electron transfer reactions.
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Affiliation(s)
- Edward B Garner
- Department of Chemistry, The University of Alabama, Shelby Hall, Tuscaloosa, AL 35487-0336, USA.
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13
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Sanchez G, Espinosa A, Curiel D, Tarraga A, Molina P. Bis(carbazolyl)ureas as selective receptors for the recognition of hydrogenpyrophosphate in aqueous media. J Org Chem 2013; 78:9725-37. [PMID: 24025043 DOI: 10.1021/jo401430d] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Recognition properties of the novel bis(carbazole) tris-ureidic-based receptors 1 and 2 toward different anions have been studied by (1)H NMR and absorption and emission spectroscopy, as well as by DFT calculations. Receptor 1, in which the two urea-functionalized arms are decorated with p-nitrophenyl rings, behaves as a highly selective chromogenic molecular probe for hydrogenpyrophosphate anion in a competitive medium (acetonitrile/water, 70/30). Receptor 2, bearing two urea arms decorated with photoactive pyrenyl rings, acts as a highly selective fluorescent molecular probe for hydrogenpyrophosphate anion in either acetonitrile or an aqueous mixture (acetonitrile/water, 85/15). Receptor 2 exhibits a dual monomer-excimer emission spectrum and undergoes a remarked ratiometry in acetonitrile in the presence of hydrogenpyrophosphate: the excimer band disappears, whereas the monomer band is slightly increased. However, in the aqueous mixture, a strong increase of the excimer emission band was observed, while the monomer emission bands remained almost unaffected. The resulting binding modes and spectroscopic features are explained by suitable structures of model complexes for both receptors. In such complexes, a peripheral cooperative effect was found, alleviating the excess of negative charge in the guest toward the outer surface of the host, as well as the required enlargement on its internal cavity.
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Affiliation(s)
- Guzman Sanchez
- Departamento de Quı́mica Orgánica, Facultad de Quı́mica Campus de Espinardo, Universidad de Murcia , E-30100 Murcia, Spain
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14
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Albrecht C, Schneider E, Engeser M, Schnakenburg G, Espinosa A, Streubel R. Synthesis and DFT calculations of spirooxaphosphirane complexes. Dalton Trans 2013; 42:8897-906. [DOI: 10.1039/c3dt50556a] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Nesterov V, Schnakenburg G, Espinosa A, Streubel R. Synthesis and Reactions of the First Room Temperature Stable Li/Cl Phosphinidenoid Complex. Inorg Chem 2012; 51:12343-9. [DOI: 10.1021/ic301652u] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Vitaly Nesterov
- Institut für Anorganische
Chemie, Rheinischen Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany
| | - Gregor Schnakenburg
- Institut für Anorganische
Chemie, Rheinischen Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany
| | - Arturo Espinosa
- Departamento de Química
Orgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain
| | - Rainer Streubel
- Institut für Anorganische
Chemie, Rheinischen Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany
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16
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Schulten C, von Frantzius G, Schnakenburg G, Espinosa A, Streubel R. Deoxygenation of carbon dioxide by electrophilic terminal phosphinidene complexes. Chem Sci 2012. [DOI: 10.1039/c2sc21081a] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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