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Sturm F, Bühler M, Stapper C, Schneider JS, Helten H, Fischer I, Röhr MIS. Impact of isoelectronic substitution on the excited state processes in polycyclic aromatic hydrocarbons: a joint experimental and theoretical study of 4 a,8 a-azaboranaphthalene. Phys Chem Chem Phys 2024; 26:7363-7370. [PMID: 38375909 DOI: 10.1039/d3cp05508f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
Substituting CC with the isoelectronic BN units is a promising approach to modify the optoelectronic properties of polycyclic aromatic hydrocarbons. While computational studies have already addressed trends in the electronic structure of the various isosteres, experimental data are still scarce. Here, the excited state spectroscopy and dynamics of 4a,8a-azaboranaphthalene were studied by picosecond time-resolved photoionization in a supersonic jet and analyzed with the aid of XMS-CASPT2 and time-dependent DFT calculations. A resonance-enhanced multiphoton ionization spectrum (REMPI) reveals the S1 origin at = 33 830 ± 12 cm-1. Several vibrational bands were resolved and assigned by comparison with the computations. A [1+1] photoelectron spectrum via the S1 origin yielded an adiabatic ionization energy of 8.27 eV. Selected vibrational bands were subsequently investigated by pump-probe photoionization. While the origin as well as several low-lying vibronic states exhibit lifetimes in the ns-range, a monoexponential decay is observed at higher excitation energies, ranging from 400 ps at +1710 cm-1 to 13 ps at +3360 cm-1. The deactivation is attributed to an internal conversion of the optically excited S1 state via a barrier that gives access to a conical intersection (CI) to the S0 state. The doping significantly changes the energetic ordering of CIs and lowers the corresponding energy barrier for the associated deactivation pathway, as revealed by nudged elastic band (NEB) calculations.
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Affiliation(s)
- Floriane Sturm
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Michael Bühler
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Christoph Stapper
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Johannes S Schneider
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB), University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Holger Helten
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB), University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Merle I S Röhr
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
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2
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Lin H, Yang X, Liu SY, Jäkle F. Ring-Opening Metathesis Polymerization of the Dewar Isomer of 1,2-Azaborinine, a B-N Isostere of Benzene. ACS Macro Lett 2024; 13:21-27. [PMID: 38095183 PMCID: PMC10842419 DOI: 10.1021/acsmacrolett.3c00601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
The successful polymerization of the Dewar isomer of an azaborinine heterocycle is reported. Controlled ring-opening metathesis polymerization was accomplished with Grubbs and Hoveya-Grubbs second generation catalysts (G2, HG2), as well as a Z-selective Ru catalyst (HGM2001). The structure of the polymers containing 4-membered B-N heterocycles was verified by GPC and multinuclear and 2D NMR. Differences in stereochemistry of polymers derived from G2/HG2 versus the Z-selective catalyst HGM2001 were substantiated by 2D NOESY, FT-IR, and Raman analyses. The incorporation of B-N heterocycles into these polymer structures is promising as a route to functional polymers that contain polar side groups.
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Affiliation(s)
- Huina Lin
- Department of Chemistry, Rutgers University - Newark, Newark, New Jersey 07102, United States
| | - Xinyu Yang
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02135, United States
| | - Shih-Yuan Liu
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02135, United States
| | - Frieder Jäkle
- Department of Chemistry, Rutgers University - Newark, Newark, New Jersey 07102, United States
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3
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Ji Y, Catazaro J, Jiang Q, Melvin SJ, Jiang J, Klausen RS. Characterization of Styrene–Vinyl Alcohol Copolymers by CP-MAS NMR Spectroscopy. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c01009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yuyang Ji
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218, United States
| | - Jonathan Catazaro
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218, United States
| | - Qifeng Jiang
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218, United States
| | - Sophia J. Melvin
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218, United States
| | - Jennifer Jiang
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218, United States
| | - Rebekka S. Klausen
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218, United States
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4
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Abstract
Dative bonding or Lewis acid-base chemistry underpins a large number of chemical phenomena in a variety of fields, such as catalysis, metal-ligand interactions, and surface chemistry. Developing light-controlled Lewis acid-base interactions could offer a new way of controlling and understanding such phenomena. Photoinduced proton transfer, that is, excited-state Brønsted acidity and basicity, has been extensively studied and applied. Here, in direct analogy to excited-state Brønsted basicity, we show that exciting a photobasic molecule with light generates a thermodynamic drive for the transfer of a Lewis acid from a donor to a photobasic molecule. We have used the archetypal BF3 as our Lewis acid and our photoactive Lewis bases are a family of quinolines, which are known Brønsted photobases as well. We have constructed the experimental Förster cycle for this system and have verified it computationally to demonstrate that a significant drive (0.2-0.7 eV) exists for the transfer of BF3 to a photoexcited quinoline. The magnitude of this drive is similar to those reported for Brønsted photobasicity in quinolines. Computational results from TDDFT and energy decomposition analysis show that the origin of such an effect is similar to the Brønsted photoactivity of these molecules, in that they follow the Hammett parameter of substituent groups. These results suggest that photobases may be capable of controlling the chemical phenomena beyond proton transfer and may open opportunities for a new handle in photocatalysis.
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Affiliation(s)
- Matthew J Voegtle
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Jahan M Dawlaty
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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5
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Wakefield IV H, Jiang Q, Klausen RS. Azaborine Isomer Effects on Benzylic Ion Stability and Reactivity: Consequences for BN2VN Ionic Polymerization. Org Biomol Chem 2022; 20:1407-1414. [DOI: 10.1039/d1ob02467a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Benzylic cations and anions are implicated in the mechanism of critical organic transformations, such as styrene polymerization. We investigate the influence of BN for CC bond substitution on the reactivity...
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6
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Ji Y, Klausen RS. Chain transfer to solvent in
BN 2‐vinylnaphthalene
radical polymerization. JOURNAL OF POLYMER SCIENCE 2021. [DOI: 10.1002/pol.20210362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Yuyang Ji
- Department of Chemistry Johns Hopkins University Baltimore Maryland USA
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7
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Mono- and Dinitro-BN-Naphthalenes: Formation and Characterization. Molecules 2021; 26:molecules26144209. [PMID: 34299484 PMCID: PMC8303104 DOI: 10.3390/molecules26144209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/03/2021] [Accepted: 07/06/2021] [Indexed: 12/01/2022] Open
Abstract
Mono- and dinitro-BN-naphthalenes, i.e., 1-nitro-, 3-nitro-, 1,6-dinitro-, 3,6-dinitro-, and 1,8-dinitro-BNN, were generated in the nitration of 9,10-BN-naphthalene (BNN), a boron–nitrogen (BN) bond-embedded naphthalene, with AcONO2 and NO2BF4 in acetonitrile. The nitrated products were isolated and characterized by NMR, GC-MS, IR, and X-ray single crystallography. The effects of the nitration on the electron density and aromaticity of BNN were evaluated by B-11 NMR analysis and HOMA calculations.
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Appiarius Y, Stauch T, Lork E, Rusch P, Bigall NC, Staubitz A. From a 1,2-azaborinine to large BN-PAHs via electrophilic cyclization: synthesis, characterization and promising optical properties. Org Chem Front 2021. [DOI: 10.1039/d0qo00723d] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A synthetic approach towards boron-nitrogen substituted polycyclic aromatic hydrocarbons (BN-PAHs) via electrophilic cyclization is described and it is shown that the variation of the rings' connectivity may tune the emission wavelengths effectively.
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Affiliation(s)
- Yannik Appiarius
- University of Bremen
- Institute for Analytical and Organic Chemistry
- D-28359 Bremen
- Germany
- MAPEX Center for Materials and Processes
| | - Tim Stauch
- MAPEX Center for Materials and Processes
- D-28359 Bremen
- Germany
- University of Bremen
- Institute for Physical and Theoretical Chemistry
| | - Enno Lork
- University of Bremen
- Institute for Physical and Theoretical Chemistry
- D-28359 Bremen
- Germany
- University of Bremen
| | - Pascal Rusch
- Bremen Center for Computational Materials Science
- D-28359 Bremen
- Germany
- Leibniz University Hannover
- Institute for Physical Chemistry and Electrochemistry
| | - Nadja C. Bigall
- Bremen Center for Computational Materials Science
- D-28359 Bremen
- Germany
- Leibniz University Hannover
- Institute for Physical Chemistry and Electrochemistry
| | - Anne Staubitz
- University of Bremen
- Institute for Analytical and Organic Chemistry
- D-28359 Bremen
- Germany
- MAPEX Center for Materials and Processes
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9
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Resendiz-Lara DA, Annibale VT, Knights AW, Chitnis SS, Manners I. High Molar Mass Poly(alkylphosphinoboranes) via Iron-Catalyzed Dehydropolymerization. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c02082] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Vincent T. Annibale
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
- Department of Chemistry, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia V8P 5C2, Canada
| | - Alastair W. Knights
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| | - Saurabh S. Chitnis
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| | - Ian Manners
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
- Department of Chemistry, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia V8P 5C2, Canada
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10
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Anderson KP, Waddington MA, Balaich GJ, Stauber JM, Bernier NA, Caram JR, Djurovich PI, Spokoyny AM. A molecular boron cluster-based chromophore with dual emission. Dalton Trans 2020; 49:16245-16251. [PMID: 32379258 DOI: 10.1039/d0dt00826e] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Bromination of the luminescent borane, anti-B18H22, via electrophilic substitution using AlCl3 and Br2, yields the monosubstituted derivative 4-Br-anti-B18H21 as an air-stable crystalline solid. In contrast to the unsubstituted parent compound, 4-Br-anti-B18H21 possesses dual emission upon excitation with UV light and exhibits fluorescence at 410 nm and phosphorescence at 503 nm, with Φtotal = 0.07 in oxygen-free cyclohexane. Increased oxygen content in cyclohexane solution quenches the phosphorescence signal. The fluorescent signal intensity remains unaffected by oxygen, suggesting that this molecule could be used as a ratiometric oxygen probe.
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Affiliation(s)
- Kierstyn P Anderson
- Department of Chemistry and Biochemistry and California NanoSystems Institute (CNSI), University of California, Los Angeles, California 90095, USA.
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11
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Makino H, Nishikawa T, Ouchi M. Elucidating Monomer Character of an Alkenyl Boronate through Radical Copolymerization Leads to Copolymer Synthesis beyond the Limitation of Copolymerizability by Side-Chain Replacement. ACS Macro Lett 2020; 9:788-793. [PMID: 35648527 DOI: 10.1021/acsmacrolett.0c00287] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Isopropenyl boronic acid pinacol ester (IPBpin) was used as a comonomer in radical polymerization with a wide range of common vinyl monomers for elucidation of the monomer character and syntheses of conventionally inaccessible copolymers via the replacement of the boron pendant. The study revealed that the boron-containing monomer is categorized into an electron-rich conjugated monomer, which was well consistent with the results of density functional theory (DFT)-based investigation. One of the thus obtained copolymers, the IPBpin-styrene copolymer, was successfully transformed into an α-methyl vinyl alcohol (MVA)-styrene counterpart via oxidation of the boron pendant. The copolymer cannot be synthesized even with the acetyl-protected monomer instead of IPBpin due to poor copolymerization ability based on the nonconjugated character.
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Affiliation(s)
- Hiroshi Makino
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 606-8501, Japan
| | - Tsuyoshi Nishikawa
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 606-8501, Japan
| | - Makoto Ouchi
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 606-8501, Japan
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12
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Ji Y, Zhou T, van de Wouw HL, Klausen RS. Organoborane Strategy for Polymers Bearing Lactone, Ester, and Alcohol Functionality. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b02201] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Yuyang Ji
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St, Baltimore, Maryland 21218, United States
| | - Tiffany Zhou
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St, Baltimore, Maryland 21218, United States
| | - Heidi L. van de Wouw
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St, Baltimore, Maryland 21218, United States
| | - Rebekka S. Klausen
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St, Baltimore, Maryland 21218, United States
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13
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Lin H, McConnell CR, Jilus B, Liu SY, Jäkle F. Changing up BN-Polystyrene: Effect of Substitution Pattern on the Free-Radical Polymerization and Polymer Properties. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00466] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Huina Lin
- Department of Chemistry, Rutgers University—Newark, Newark, New Jersey 07102, United States
| | - Cameron R. McConnell
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02135, United States
| | - Berothy Jilus
- Department of Chemistry, Rutgers University—Newark, Newark, New Jersey 07102, United States
| | - Shih-Yuan Liu
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02135, United States
| | - Frieder Jäkle
- Department of Chemistry, Rutgers University—Newark, Newark, New Jersey 07102, United States
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