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Cross MJ, Brodie CN, Crivoi DG, Goodall JC, Ryan DE, Martínez‐Martínez AJ, Johnson A, Weller AS. Dehydropolymerization of Amine-Boranes using Bis(imino)pyridine Rhodium Pre-Catalysis: σ-Amine-Borane Complexes, Nanoparticles, and Low Residual-Metal BN-Polymers that can be Chemically Repurposed. Chemistry 2023; 29:e202302110. [PMID: 37530441 PMCID: PMC10947130 DOI: 10.1002/chem.202302110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 07/31/2023] [Accepted: 08/02/2023] [Indexed: 08/03/2023]
Abstract
The sigma amine-borane complexes [Rh(L1)(η2 :η2 -H3 B⋅NRH2 )][OTf] (L1=2,6-bis-[1-(2,6-diisopropylphenylimino)ethyl]pyridine, R=Me, Et, n Pr) are described, alongside [Rh(L1)(NMeH2 )][OTf]. Using R=Me as a pre-catalyst (1 mol %) the dehydropolymerization of H3 B ⋅ NMeH2 gives [H2 BNMeH]n selectively. Added NMeH2 , or the direct use of [Rh(L1)(NMeH2 )][OTf], is required for initiation of catalysis, which is suggested to operate through the formation of a neutral hydride complex, Rh(L1)H. The formation of small (1-5 nm) nanoparticles is observed at the end of catalysis, but studies are ambiguous as to whether the catalysis is solely nanoparticle promoted or if there is a molecular homogeneous component. [Rh(L1)(NMeH2 )][OTf] is shown to operate at 0.025 mol % loadings on a 2 g scale of H3 B ⋅ NMeH2 to give polyaminoborane [H2 BNMeH]n [Mn =30,900 g/mol, Ð=1.8] that can be purified to a low residual [Rh] (6 μg/g). Addition of Na[N(SiMe3 )2 ] to [H2 BNMeH]n results in selective depolymerization to form the eee-isomer of N,N,N-trimethylcyclotriborazane [H2 BNMeH]3 : the chemical repurposing of a main-group polymer.
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Affiliation(s)
| | | | - Dana G. Crivoi
- Department of ChemistryUniversity of OxfordOxfordOX1 3TAUK
| | | | - David E. Ryan
- Department of ChemistryUniversity of YorkYorkYO10 5DDUK
- Department of ChemistryUniversity of OxfordOxfordOX1 3TAUK
| | - Antonio J. Martínez‐Martínez
- Department of ChemistryUniversity of OxfordOxfordOX1 3TAUK
- Supramolecular Organometallic and Main Group Chemistry Laboratory CIQSO-Center for Research in Sustainable Chemistry and Department of ChemistryUniversity of HuelvaCampus El Carmen21007HuelvaSpain
| | - Alice Johnson
- Department of ChemistryUniversity of OxfordOxfordOX1 3TAUK
- Department of Biosciences and ChemistrySheffield Hallam UniversityHoward StSheffieldS1 1WBUK
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2
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Braese J, Lehnfeld F, Annibale VT, Oswald T, Beckhaus R, Manners I, Scheer M. Titanium-Catalyzed Polymerization of a Lewis Base-Stabilized Phosphinoborane. Chemistry 2023; 29:e202301741. [PMID: 37498679 DOI: 10.1002/chem.202301741] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/21/2023] [Accepted: 07/27/2023] [Indexed: 07/29/2023]
Abstract
The reaction of the Lewis base-stabilized phosphinoborane monomer tBuHPBH2 NMe3 (2 a) with catalytic amounts of bis(η5 :η1 -adamantylidenepentafulvene)titanium (1) provides a convenient new route to the polyphosphinoborane [tBuPH-BH2 ]n (3 a). This method offers access to high molar mass materials under mild conditions and with short reaction times (20 °C, 1 h in toluene). It represents an unprecedented example of a transition metal-mediated polymerization of a Lewis base-stabilized Group 13/15 compound. Preliminary studies of the substrate scope and a potential mechanism are reported.
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Affiliation(s)
- Jens Braese
- Universität Regensburg, Institut für Anorganische Chemie, 94053, Regensburg, Germany
| | - Felix Lehnfeld
- Universität Regensburg, Institut für Anorganische Chemie, 94053, Regensburg, Germany
| | - Vincent T Annibale
- University of Victoria, Department of Chemistry, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada
| | - Tim Oswald
- Carl von Ossietzky Universität Oldenburg, Institut für Chemie Carl-von-Ossietzky, Straße 9-11, 26129, Oldenburg, Germany
| | - Rüdiger Beckhaus
- Carl von Ossietzky Universität Oldenburg, Institut für Chemie Carl-von-Ossietzky, Straße 9-11, 26129, Oldenburg, Germany
| | - Ian Manners
- University of Victoria, Department of Chemistry, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada
| | - Manfred Scheer
- Universität Regensburg, Institut für Anorganische Chemie, 94053, Regensburg, Germany
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3
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Zhang Y, Zhang X, Yan Q. Synthesis, Structure, and Properties of Monodispersed and Highly Luminescent Organoborane Oligomers. J Org Chem 2023. [PMID: 37467361 DOI: 10.1021/acs.joc.3c00629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
Abstract
Organoborane oligomers with well-defined molecular structures and high luminescence are scarce, among which those with boron not used as bridging atoms are even more so. Here, a series of well-defined ethynyl-linked or butadiynyl-linked conjugated organoborane oligomers with high fluorescence quantum yield and extinction coefficient (i.e., high brightness) were prepared by coupling different building blocks featuring dithienooxadiborepine moieties. Single crystal structures of hexyl modified dithienooxadiborepine (1a-hex) and hexyl-modified butadiynyl-linked conjugated dimer (D2-hex) not only verified the identity of the molecular structures but also revealed that the introduction of the hexyl chains distorted the molecular structures due to steric hindrance. Optical measurements showed that the absorption and emission maxima of the six oligomeric molecules bathochromic shifted with increasing numbers of repeating units. Molecules without hexyl chains emit efficient fluorescence upon photoexcitation, and the fluorescence quantum efficiency of the ethynyl-linked conjugated dimer (D1) is close to unity. Theoretical calculation results using density functional theory methods are consistent with the single crystal data, allowing a better understanding of the spectral properties. Such results indicate that the method is efficient for expanding small organoborane molecules into π-conjugated oligomers, which can be used to modulate to emit different colors with high efficiency.
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Affiliation(s)
- Yumei Zhang
- Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Xinnan Zhang
- Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Qifan Yan
- Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
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4
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Moussa ME, Kahoun T, Marquardt C, Ackermann MT, Hegen O, Seidl M, Timoshkin AY, Virovets AV, Bodensteiner M, Scheer M. Three- and Five-Membered Anionic Chains of Pnictogenylboranes. Chemistry 2023; 29:e202203206. [PMID: 36478481 DOI: 10.1002/chem.202203206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/06/2022] [Accepted: 12/07/2022] [Indexed: 12/12/2022]
Abstract
An unprecedented family of three- and five-membered substituted anionic derivatives of parent pnictogenylboranes is herein reported. Reacting various combinations of the pnictogenylboranes H2 E'-BH2 -NMe3 (E'=P, As) with pnictogen-based nucleophiles MER1R2 (E=P, As; R1=H, R2=t Bu; R1=R2=Ph; M=Na, K) allows for the isolation of the unsymmetrical products [Na(18-crown-6)][H2 E'-BH2 -EHt Bu] (3: E=E'=P; 4: E=E'=As; 5: E=As, E'=P) and [M(C)][H2 E'-BH2 -EPh2 ] (7: E=E'=P, M=Na, C=18-crown-6; 8: E=E'=As; M=K, C=[2.2.2]cryptand; 9: E=P, E'=As, M=Na, C=[2.2.2]cryptand; 10: E=As, E'=P, M=K, C=[2.2.2]cryptand). [Na(18-crown-6)][H2 As-BH2 -t BuPH-BH3 ] (6) is only accessible by a different pathway, using t BuPH2 , BH3 ⋅ SMe2 and NaNH2 as starting materials. Additionally, the synthesis of symmetrical diphenyl-substituted compounds [M(18-crown-6)][Ph2 E-BH2 -EPh2 ] (11: E=P, M=Na; 12: E=As, M=K) is reported which can be regarded as isostructural inorganic, negatively charged analogs of dppm (1,1-bis(diphenylphosphino)methane) and dpam (1,1-bis(diphenylarsino)methane). Furthermore, an elongation of the pnictogen boron backbone in compounds 3, 7 and 9' (similar compound to 9, stabilized however by 18-crown-6), is attainable by reacting them with the pnictogenylboranes H2 E'-BH2 -NMe3 leading to corresponding five-membered chain-like compounds [Na(18-crown-6)][H2 E-BH2 -R1R2P-BH2 -E'H2 ] (E=E'=P, R1=H, R2=t Bu (13); E=E'=P, R1=R2=Ph (14); E=E'=As, R1=R2=Ph (15); E=P, E'=As, R1=R2=Ph (16)). Finally, the thermodynamics of the reaction pathways were evaluated by quantum chemical computations.
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Affiliation(s)
- Mehdi Elsayed Moussa
- Institut für Anorganische Chemie der, Universität Regensburg, 93040, Regensburg, Germany
| | - Tobias Kahoun
- Institut für Anorganische Chemie der, Universität Regensburg, 93040, Regensburg, Germany
| | - Christian Marquardt
- Institut für Anorganische Chemie der, Universität Regensburg, 93040, Regensburg, Germany
| | - Matthias T Ackermann
- Institut für Anorganische Chemie der, Universität Regensburg, 93040, Regensburg, Germany
| | - Oliver Hegen
- Institut für Anorganische Chemie der, Universität Regensburg, 93040, Regensburg, Germany
| | - Michael Seidl
- Institut für Anorganische Chemie der, Universität Regensburg, 93040, Regensburg, Germany
| | - Alexey Y Timoshkin
- Institute of Chemistry, St. Petersburg State University, Universitetskaya nab. 7/9, 199034, St. Petersburg, Russia
| | - Alexander V Virovets
- Institut für Anorganische Chemie der, Universität Regensburg, 93040, Regensburg, Germany
| | - Michael Bodensteiner
- Institut für Anorganische Chemie der, Universität Regensburg, 93040, Regensburg, Germany
| | - Manfred Scheer
- Institut für Anorganische Chemie der, Universität Regensburg, 93040, Regensburg, Germany
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5
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Race JJ, Heyam A, Wiebe MA, Diego-Garcia Hernandez J, Ellis CE, Lei S, Manners I, Weller AS. Polyphosphinoborane Block Copolymer Synthesis Using Catalytic Reversible Chain-Transfer Dehydropolymerization. Angew Chem Int Ed Engl 2023; 62:e202216106. [PMID: 36394131 PMCID: PMC10107156 DOI: 10.1002/anie.202216106] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/15/2022] [Accepted: 11/17/2022] [Indexed: 11/19/2022]
Abstract
An amphiphilic block copolymer of polyphosphinoborane has been prepared by a mechanism-led strategy of the sequential catalytic dehydropolymerization of precursor monomers, H3 B ⋅ PRH2 (R=Ph, n-hexyl), using the simple pre-catalyst [Rh(Ph2 PCH2 CH2 PPh2 )2 ]Cl. Speciation, mechanism and polymer chain growth studies support a step-growth process where reversible chain transfer occurs, i.e. H3 B ⋅ PRH2 /oligomer/polymer can all coordinate with, and be activated by, the catalyst. Block copolymer [H2 BPPhH]110 -b-[H2 BP(n-hexyl)H]11 can be synthesized and self-assembles in solution to form either rod-like micelles or vesicles depending on solvent polarity.
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Affiliation(s)
- James J Race
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.,Chemistry Research Laboratories, University of Oxford, Oxford, OX1 3TA, UK
| | - Alex Heyam
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK
| | - Matthew A Wiebe
- Department of Chemistry, University of Victoria, Victoria, BC, V8P 5C2, Canada
| | | | - Charlotte E Ellis
- Department of Chemistry, University of Victoria, Victoria, BC, V8P 5C2, Canada
| | - Shixing Lei
- Department of Chemistry, University of Victoria, Victoria, BC, V8P 5C2, Canada
| | - Ian Manners
- Department of Chemistry, University of Victoria, Victoria, BC, V8P 5C2, Canada.,Centre for Advanced Materials and Related Technology (CAMTEC), University of Victoria, Victoria, BC, V8P 5C2, Canada
| | - Andrew S Weller
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK
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Wiebe MA, Kundu S, LaPierre EA, Patrick BO, Manners I. Transition-Metal-Free Dehydropolymerization of Phosphine-Boranes at Ambient Temperature. Chemistry 2023; 29:e202202897. [PMID: 36196020 DOI: 10.1002/chem.202202897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Indexed: 11/16/2022]
Abstract
Stoichiometric reaction of phosphine-borane adducts RR'PH⋅BH3 (R=Ph, R'=H, Ph, Et, and R=R'=t Bu) with the strong acid HNTf2 (Tf=SO2 CF3 ) leads to H2 elimination and the formation of the triflimido derivatives, RR'PH⋅BH2 (NTf2 ). Subsequent deprotonation by using bases, such as diisopropylethylamine or the carbene IPr (IPr=N,N'-bis(2,6-diisopropylphenyl)imidazol-2-ylidene), led to the formation of P-mono- or -disubstituted polyphosphinoboranes [RR'P-BH2 ]n . Evidence for the intermediacy of transient phosphinoborane monomers, RR'PBH2 , was provided by trapping reactions.
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Affiliation(s)
- Matthew A Wiebe
- Department of Chemistry, University of Victoria, 3800 Finnerty Rd, Victoria, British Columbia, V8P 5 C2, Canada
| | - Subrata Kundu
- Department of Chemistry, University of Victoria, 3800 Finnerty Rd, Victoria, British Columbia, V8P 5 C2, Canada.,Department of Chemistry, Indian Institute of Technology Delhi Hauz Khas, New Delhi, 110016, India
| | - Etienne A LaPierre
- Department of Chemistry, University of Victoria, 3800 Finnerty Rd, Victoria, British Columbia, V8P 5 C2, Canada
| | - Brian O Patrick
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T 1Z1, Canada
| | - Ian Manners
- Department of Chemistry, University of Victoria, 3800 Finnerty Rd, Victoria, British Columbia, V8P 5 C2, Canada
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7
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Knights AW, Nascimento MA, Manners I. An investigation of polyphosphinoboranes as flame-retardant materials. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.124795] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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